Saturn-Apollo Applications: Combining Missions to Save Rockets, Spacecraft, and Money (1966)

This cutaway illustration of the Saturn V rocket configured for Apollo lunar missions needs some explanation. "Apollo Capsule" is a label almost never applied to the Apollo Command and Service Module (CSM) spacecraft. "LOX" is liquid oxygen. In the top two stages of the three-stage rocket, fuel tanks hold liquid hydrogen; the first stage fuel tank contains RP-1 aviation fuel similar to kerosene. Image credit: NASA.

Long before NASA reached the Moon, the U.S. civilian space agency's managers and engineers began to look at ways of using Apollo lunar hardware in non-lunar and advanced lunar missions. In April 1963, for example, the Manned Spacecraft Center (MSC) in Houston awarded North American Aviation (NAA), prime contractor for the three-man Apollo Command and Service Module (CSM) spacecraft, a contract to study modifying the CSM to serve as a six-man crew transport and logistics resupply vehicle for a 24-man Earth-orbiting space station.

In early 1964, President Lyndon Baines Johnson asked NASA Administrator James Webb to plan a future space program based on Apollo hardware. The primary goal was to squeeze the Apollo investment for all it was worth. NASA began to study options for using Apollo hardware for new missions. Progress in 1964 was minimal in part because the space agency was oversubscribed. In addition to creating Apollo spacecraft, launchers, and infrastructure, NASA was preparing Project Gemini, a series of 10 piloted missions meant to teach American astronauts rendezvous and docking and spacewalk techniques required for Apollo Moon flights and to confirm that astronauts could live in space long enough (up to two weeks) to accomplish a lunar mission.

On 18 February 1965, George Mueller, NASA Associate Administrator for Manned Space Flight, told the U.S. House of Representatives Committee on Science and Astronautics that repurposing Apollo hardware would enable NASA "to perform a number of useful missions. . .in an earlier time-frame than might otherwise be expected" and at a fraction of the cost of developing wholly new spacecraft. He explained that NASA's program for applying Apollo hardware to new missions "would follow the basic Apollo manned lunar landing program and would represent an intermediate step between this important national goal and future manned space flight programs." At the time he testified, the first manned lunar landing attempt was slated for late 1967 or early 1968.

Six months later, in August 1965, Mueller established the Saturn-Apollo Applications (SAA) Office at NASA Headquarters. The new organization quickly began efforts to define the SAA Program's hardware requirements and mission manifest. At about the same time, SAA began to be referred to as the Apollo Applications Program (AAP), the name by which it is best known today.

In late January 1966, Mueller wrote to the directors of the three main NASA facilities dedicated to piloted spaceflight — MSC, the Marshall Space Flight Center (MSFC) in Huntsville, Alabama, and Kennedy Space Center (KSC), Florida — to sum up SAA's evolving objectives. He told Robert Gilruth (MSC), Wernher von Braun (MSFC), and Kurt Debus (KSC) that, in addition to readying NASA for its next Apollo-scale space goal — no one knew what that would be in early 1966, though a large Earth-orbiting space station stood near the top of the list — SAA should provide immediate benefits to the American public in areas as diverse as air pollution control, Earth-resources remote sensing, improved weather forecasting, materials science, and communications satellite repair.

Apollo spacecraft and rockets in 1966. The "Uprated Saturn I" rocket at lower right, used for Earth-orbital missions, would soon be renamed the Saturn IB. Image credit: NASA.

By March 1966, the SAA Program Office had compiled a list of potential new missions for Apollo hardware. From MSC and NAA came proposals for CSM missions in low-Earth orbit (LEO), geosynchronous orbit, and lunar orbit. MSFC proposed that the spent S-IVB second stages of Saturn IB rockets be outfitted in LEO to serve double-duty as pressurized "workshops."

Apollo Lunar Module (LM) prime contractor Grumman suggested that LMs without legs or ascent engines might serve as Earth-orbital and lunar-orbital scientific instrument carriers and mini-laboratories. The company also proposed manned and unmanned LM variants — respectively the LM Taxi and the LM Shelter — for 14-day lunar surface stays. The LM Shelter design took several forms; most carried surface transportation systems (rovers or flyers).

All of these spacecraft would reach space atop Apollo Saturn IB and Saturn V rockets, some of which might be uprated for increased payload capacity. In its early SAA planning, NASA referred to missions by their launch vehicle designations. The second, third, and fourth Saturn V-launched SAA missions were thus called AS-511, AS-512, and AS-513 because they would use the 11th, 12th, and 13th of 15 Saturn V rockets purchased for Apollo. SAA planners assumed that, the moment Apollo achieved its goal of a man on the Moon, all remaining Apollo hardware would be released to the SAA Program.

The image above shows an Apollo Command and Service Module (CSM) spacecraft docked with a proposed Lunar Module (LM) variant meant to serve as a telescope mount for an SAA Workshop in Earth orbit. The AS-511 LM Lab would have shared many features with this design. Image credit: Grumman/NASA.

The SAA Program Office envisioned AS-511 as a CSM-LM Lab mission that would map the Moon from lunar polar orbit. Its three-man crew would operate mapping cameras and sensors mounted on the LM Lab as the Moon revolved beneath their spacecraft, then would cast off the LM Lab and ignite their CSM's single Service Propulsion System (SPS) main engine to leave lunar orbit and return to Earth.

AS-512 would see a three-man CSM deliver an uncrewed LM Shelter to near-equatorial lunar orbit. The LM Shelter would undock and descend automatically to a preselected landing site. The three astronauts would then return to Earth.

AS-513, the first SAA piloted lunar landing mission, would launch less than three months after AS-512. Two astronauts would land near the LM Shelter in an LM Taxi while a third astronaut remained in lunar orbit on board an Extended Capability CSM (XCSM) with an independent space endurance of 45 days. The surface astronauts would place their LM Taxi in "hibernation" and use the LM Shelter as their base of operations for 14 days of exploration. A lunar day-night period lasts about 28 days at most sites, so if they landed at local dawn they would leave the lunar surface at local dusk.

The SAA Program Office solicited comment on its plans from Bellcomm, NASA Headquarters' Washington, DC-based Apollo planning contractor. On 4 April 1966, Bellcomm engineer P. W. Conrad (not to be confused with astronaut Charles "Pete" Conrad) wrote a brief memorandum in which he proposed that the AS-511 and AS-512 missions be merged.

Conrad wrote that AS-511 did not need an LM Lab: its CSM could carry the cameras, film, sensors, and magnetic tape it would need for lunar-orbital mapping. He noted also that, in the SAA Program plan, the AS-512 CSM would be a mere "escort" for the LM Shelter, leaving its crew with relatively few meaningful duties. A mission in which a CSM bearing mapping instrumentation carried the LM Shelter to the Moon would keep its crew productively occupied, Conrad argued, and would free up a Saturn V, a CSM, and an LM Lab for other SAA missions.

He examined two possible profiles for the combined mission. In the first, which Conrad called "direct descent," the CSM would release the unmanned LM Shelter immediately following the last SPS course-correction burn en route to the Moon. The LM Shelter would fall toward the Moon's Nearside without entering orbit. Fifty thousand feet above its target landing area, it would automatically ignite its Descent Propulsion System (DPS) engine to decelerate, hover until it found a safe spot, and land.

The piloted CSM, meanwhile, would pass over one of the lunar poles and fire its SPS behind the Moon to perform Lunar Orbit Insertion (LOI); that is, it would slow down so that the Moon's gravity could capture it into polar mapping orbit.

As the CSM orbited, the Moon would revolve beneath it. If it were a Block II CSM with 14-day endurance, it would orbit the Moon for from five to eight days. After about seven days, the CSM would pass over half the Moon's surface and map about one quarter in daylight.

If it were an XCSM, it would orbit for about 28 days. After 14 days, it would pass over the entire lunar surface and map half in daylight. At the end of 28 days, it would pass over the entire lunar surface twice and map the entire surface in daylight. At the planned end of its time in lunar polar orbit — or sooner, if some fault developed that required an early Earth return — the XCSM would ignite its SPS behind the Moon to depart lunar polar orbit for Earth.

Conrad's second combined mission profile would see the LM Shelter remain docked to the CSM until some time after LOI. The CSM would ignite its SPS to slow itself and the LM Shelter so that the Moon's gravity could capture the docked spacecraft into polar orbit, then the crew would turn CSM-mounted cameras and sensors toward the moon.

As the CSM and LM Shelter orbited over the lunar poles, the Moon would revolve beneath them, so that within a few days of LOI the LM Shelter's Nearside target landing site would move into position for descent and landing. The LM Shelter would then undock from the CSM and automatically ignite its DPS to begin descent over the Moon's Farside hemisphere about 180° of longitude from its landing site. It would fire the DPS again close to the landing site to carry out powered descent, hover, and landing. The CSM astronauts, meanwhile, would continue their lunar-orbital mapping mission.

Conrad acknowledged that both scenarios had their advantages and disadvantages. Direct descent would require that the LM Shelter carry extra landing propellants, which might limit the mass of exploration equipment and life support consumables it could place on the Moon. This might in turn limit the scope of the two-week exploration it was meant to support. In addition, the LM Shelter's DPS would not be available as an SPS backup or supplement if an abort were declared before LOI or in lunar orbit.

On the plus side, relieving the CSM of the LM Shelter's mass ahead of LOI would reduce the quantity of propellants the SPS would need to expend to accomplish LOI. The mass freed up by reducing the CSM's propellant load could be applied to additional CSM cameras, film, sensors, magnetic tape, and life support consumables.

Retaining the LM Shelter until after LOI would maximize its payload mass, but would also require that the CSM carry more LOI propellants. This might lead to a reduction in the mass that could be devoted to cameras, film, sensors, tape, and life support consumables on board the CSM. On the other hand, the LM Shelter DPS would remain available as a backup or supplement to the SPS at least through LOI and, in almost all cases, for several days thereafter.

The SAA Program evolved rapidly. Conrad's proposal appears, however, not to have exerted much influence on SAA planners.

More consequential by far was the AS-204/Apollo 1 fire (27 January 1967), which killed astronauts Gus Grissom, Ed White, and Roger Chaffee. The fire, which revealed fundamental flaws in Apollo Program quality-control and contractor oversight, undermined support in Congress for NASA and, along with LM development delays, put off the first piloted lunar landing until July 1969. All six piloted Moon landings took place within the Apollo Program, and neither an Apollo lunar polar orbit mission nor a lunar surface stay longer than about three days was accomplished.

The Saturn V rocket designated AS-511 in Conrad's memo launched the Apollo 16 lunar landing mission in April 1972. By then, NASA had changed its designation to SA-511. The SA-512 Saturn V launched Apollo 17, the final lunar landing mission, in December 1972, and SA-513 launched the Earth-orbital Skylab Orbital Workshop, the sole surviving remnant of what had been the SAA Program, in May 1973.

A lunar polar orbiter would have to wait until 1994, when the Ballistic Missile Defense Organization launched the 424-kilogram Clementine spacecraft (25 January 1994). The U.S. Department of Defense spacecraft followed a circuitous route to the Moon, at last arriving in mapping orbit on 19 February 1994. Though it accomplished a science mission, Clementine was conceived as a test of sensors and other technologies that would be used to detect and intercept nuclear-tipped missiles launched against the United States.

In an experiment using Earth-based radar, Clementine found the first indications of hydrogen concentrations in permanently shadowed craters near the Moon's poles. These were widely interpreted as signs of water ice, though the quantity of ice and its exact location could not be reliably determined. Clementine mapped the Moon until 3 May 1994, when it left lunar polar orbit bound for the near-Earth asteroid 1620 Geographos. A malfunction on 7 May 1994 caused Clementine to expend its propellant, however, scrubbing the asteroid flyby.

Japan's SELENE/Kaguya lunar polar orbiter with one of its two sub-satellites (center right). The spacecraft orbited the Moon from 3 October 2007 through 10 June 2009. Image credit: JAXA.

NASA had sought to launch a robotic lunar polar orbiter since the 1960s. Not until 7 January 1998, however, did the Lunar Prospector mission begin. Lunar Prospector reached lunar polar orbit on 11 January 1998 and mapped the Moon until it was intentionally deorbited on 31 January 1999. The spacecraft crashed near the Moon's south pole, where it had detected more signs of water ice in permanently shadowed craters.

Since Lunar Prospector, the United States, Europe, Japan, China, and India have all launched automated spacecraft into lunar polar orbit. As of May 2018, however, only one (NASA's Lunar Reconnaissance Orbiter, launched 18 June 2009) still operates. New lunar polar orbiters are, however, in the planning and development stages: for example, the Republic of Korea (South Korea) plans to launch the Korean Pathfinder Lunar Orbiter in 2020.

Sources

"Combining Lunar Polar Orbit Mission with an Unmanned Landing, Case 218," P. W. Conrad, Bellcomm, 4 April 1966.

Living and Working in Space: A History of Skylab, NASA SP-4298, W. David Compton and Charles Benson, NASA, 1983.

Korea Aerospace Research Institute: Lunar Exploration (https://www.kari.re.kr/eng/sub03_04.do - accessed 5 May 2018)

Related Posts

Space Station Resupply: The 1963 Plan to Turn the Apollo Spacecraft into a Space Freighter

"Assuming That Everything Goes Perfectly Well in the Apollo Program. . ." (1967)

"A True Gateway": Robert Gilruth's June 1968 Space Station Presentation

Log of a Moon Expedition (1969)

Luděk Pešek's lunar expedition was intended to alight in Sinus Medii, a relatively flat region NASA would in fact select as an alternate landing site for early Apollo missions. In his book, Pešek generated drama by landing his eight-man crew off-course in rugged, unstable terrain between Reaumur and Flammarion. Image credit: Defense Mapping Agency/U.S. Geological Survey.

In the 1969-1973 period, the post-Apollo era of robotic planetary reconnaissance was only beginning. The National Geographic Society wanted to give its members a preview, so it turned to Luděk Pešek. Born in Czechoslovakia in 1919, Pešek was out of his home country when Warsaw Pact tanks crushed the 1968 Prague Spring. Rather than return home to tyranny, he took up residence in Switzerland and became a Swiss citizen.

Luděk Pešek's photorealistic paintings of planets and moons dominated the August 1970 and February 1973 issues of National Geographic magazine. The 1970 magazine took in the entire Solar System. It bore on its cover Pešek's painting of Saturn as seen from the moon Titan. The 1973 issue celebrated the discoveries scientists had made using cameras on the Mars probe Mariner 9, the first spacecraft to orbit another planet. The magazine included as a supplement an airbrushed map of Mars based on images from Mariner 9 and Earth-based telescopes. The map's reverse side featured Pešek's impression of the surface of Mars during a dust storm. It was probably the last great artistic rendering of the martian surface before Viking 1, the first successful Mars lander, touched down in Chryse Planitia on 20 July 1976.

Though remembered mainly as an artist, Pešek was also a writer. In 1964, as the real-life Moon Race between the Soviet Union and the United States gathered pace, Pešek penned a short novel about a lunar expedition. It was published first in the Federal Republic of Germany (West Germany) in 1967, then in the United States as Log of a Moon Expedition in 1969, a few months before the Apollo 11 Lunar Module Eagle became the first piloted spacecraft to land on the Moon.

Pešek's account now reads like alternate history. Although billed in the U.S. at the time of its publication as a book for children, it is hard to believe that Log of a Moon Expedition earned much affection from that hard-to-please audience. This might account for the fact that it is not well known today. Pešek's tale reads like a technical paper told through a first-person narrator. Though fiction, its many technical details make it fair game for discussion in this blog.

Pešek described a lunar program that began with several years of hardware development, testing in Earth orbit, and at least four precursor lunar flights. An automated sample-returner collected rocks at the proposed landing site and returned them to Earth for engineering analysis. Meanwhile, at least one automated spacecraft and at least two piloted expeditions (designated KM I and KM II) imaged the Moon's surface from lunar orbit.

Pešek considered the first piloted Moon landing to be the first step in Project Alpha, the intensive exploration of the entire Solar System by astronauts. He did not specify which country or consortium would carry out Project Alpha, nor did he provide a location for "Earth Control," the equivalent of NASA's Mission Control Center in Houston, ESA's European Space Operations Centre in Darmstadt, or the Flight Control Center near Moscow.

Spacecraft KM III. Image credit: Luděk Pešek/Alfred A. Knopf, Jr.

Pešek dispatched his lunar spacecraft, which he dubbed KM III, to Sinus Medii (Central Bay), a patch of relatively smooth, relatively flat mare ("sea") terrain at the center of the Moon's Earth-facing Nearside hemisphere. KM III was streamlined, with tail fins, short wings, a pointed nose, and at least one tail-mounted chemical-propellant rocket engine. It was designed to land upright, with its nose pointed at the black lunar sky, on "stilts" that extended from its tail fins. Each stilt ended in a large rectangular footpad.

Its pressurized cabin housed padded "anti-gravity" (acceleration) couches for eight men, a communications and meteoroid-monitoring radio/radar station, and an impressive array of stores and equipment, including at least 16 180-pound steel-shelled space suits (two for each expedition member). An airlock led from the cabin to the lunar surface.

Before KM III left Earth, three automated cargo landers landed in Sinus Medii. Designated S 1, S 2, and S 3, they set down in a triangular pattern about 15 miles wide. Fat drums about 50 feet tall with silver-and-gray dome-shaped tops, the cargo landers each contained scientific equipment, tools, sturdy electricity-powered tractors with unpressurized cabins for lunar surface transport, construction materials, a pressurized living volume stocked with air, water, and food, and, most important, 40 tons of Earth-return propellant for KM III, which would land on the Moon with nearly dry tanks. Forty tons of propellant were sufficient to launch KM III off the Moon and place it on course for Earth.

Cargo lander S2 with astronaut in open doorway for scale. Image credit: Luděk Pešek/Alfred A. Knopf, Jr.

The expedition was planned to last eight Earth days. KM III was meant to land on level ground at the center of the S 1-S 2-S 3 triangle just after lunar dawn. Pešek wrote that the expedition included enough supplies to remain on the Moon for 14 Earth days (about one lunar daylight period), but that it could not stay past lunar sunset.

This was because the landers and tractors drew electricity from batteries kept charged by dish-shaped solar concentrators. Silver dishes would focus sunlight onto a boiler containing a working fluid that would turn to gas, move through pipes to a turbine generator which would make electricity, pass through radiators to shed heat and return to liquid form, and then return to the boiler to begin the cycle again.

Pešek did not give his intrepid lunar explorers names. Instead, they had three-letter "shortwave radio" designations. CAP was the calm, stoic leader of the expedition, while DOC, the narrator, was the "documenter" and photographer. MEC was the wise-cracking mechanic and navigator, PHY the expedition doctor, and RNT the radio and TV engineer. The expedition included three scientists: GEO, a geologist; AST, an astrophysicist specializing in radiation; and SEL, a selenologist ("Moon scientist").

A lunar expedition crewmember in a Moon suit. The numeral "5" on this suit's backpack identifies its wearer as MEC. Image credit: Luděk Pešek/Alfred A. Knopf, Jr.

Murphy's Law ruled Pešek's lunar expedition. Trouble began even before KM III left Earth. The S 1, S 2, and S 3 landers landed in a triangle as planned, but its center was about 20 miles south of the intended target zone. This placed it uncomfortably close to rocky, rifted terrain between the craters Reaumur and Flammarion. Despite this inexplicable navigational error, Earth Control decided to launch KM III on schedule.

The explorers did not pilot their spacecraft during descent to the Moon. Instead, they strapped into their couches so that they could withstand KM III's rapid deceleration. The spacecraft's guidance system locked automatically onto the cargo lander homing beacons and steered it to a landing.

At touchdown, KM III automatically released a "natrium" (sodium) cloud that fluoresced in lunar dawn light, permitting Earth-based telescopic observers to confirm its location on the lunar surface.

As they waited for the sodium cloud to disperse so that they could see outside, the explorers worried that they had landed off target. Only S 1's homing beacon came in loud and clear. Their radio could not pick up a signal from S 2 and S 3's signal was very weak. In addition, the ground was less stable than anticipated: KM III had an alarming tendency to list to one side. The crew extended the landing stilt on that side to keep their spacecraft level.

When the shadowy landscape around KM III became visible outside the viewports, it was unfamiliar. No elevated surface features should have been visible, yet there was a 190-foot-tall hill a few hundred yards to the north and a taller ridge beyond that. They named the former Revelation Hill. As the gravity of their predicament became clear, they dubbed the latter Disappointment Ridge.

First, however, CAP and DOC donned their cumbersome armored Moon suits and took humankind's first small steps on another world. Pešek wrote that, when they shook hands outside KM III, they felt as though they were "congratulating mankind." They then inspected KM III's landing stilts. All were sunk into the rock deeper than expected. On the side toward which their spacecraft listed, the stilt was extended to half its total length.

Soon after CAP and DOC climbed back inside KM III, Earth Control confirmed that the same navigational error that had affected the cargo landers had caused their spacecraft to land at least 20 miles southwest of its target. This placed KM III entirely outside the triangle formed by the cargo landers. S 3, most northerly of the three, was out of reach at a distance of at least 35 miles.

The expedition got to work. They injected "oxycrete," a specially constituted lunar concrete, under the deeply sunken landing stilt to shore up KM III. Next, they set up a 15-foot-diameter solar concentrator near KM III to charge its batteries. They also erected a 130-foot-tall radio-relay tower atop Revelation Hill to extend their radio range. When they did, they picked up S 2's signal.

The cargo lander was just five miles away and apparently in good condition, but it was beyond Disappointment Ridge, on the far side of a jagged rift up to 65 feet wide and 150 feet deep. The rift, which began close to Reaumur crater, ran for many miles, often through rugged terrain, so could not be circumvented.

The path to S 1, on the other hand, appeared mostly clear, though the lander was about 17 miles away from KM III. A three-man sortie party consisting of DOC, RNT, and AST set out on foot to retrieve S 1's tractor so that the expedition could begin to transfer Earth-return propellant stored in tanks inside the lander to KM III.

Unfortunately, the terrain was not as easily navigated as expected. The sortie party became trapped in a labyrinth of small craters and rifts. After hiking at least 20 miles, they were still more than five miles from S 1. Uncertain that they could reach S 1 in time to refill their Moon suit oxygen tanks, they reluctantly turned back toward KM III.

On the way home, the radio signal from KM III abruptly stopped. The party feared the worst — that the spacecraft had fallen over or suffered some other sudden calamity.

AST's Moon suit oxygen system then malfunctioned, so that he became exhausted and had to be carried. The trio abandoned a large camera and other equipment. Fearing for the lives of his companions, AST begged to be left behind, too.

Fortunately, DOC spotted a signal flare on the horizon. Shortly after that, the sortie party resumed radio contact with KM III. The main radio transmitter had been down for four hours; repair had been slowed by RNT's absence.

Soon after the exhausted sortie party returned to KM III, the expedition abandoned all thought of scientific research so that its members could concentrate on saving themselves. This was discouraging to all the expedition members, not only the three scientists.

Pešek displayed his artistic bent when he described the shadows the glaring Sun cast on the lunar surface as it climbed toward the zenith, then began its slow fall toward the horizon and eventual nightfall at the KM III landing site. He described the effect the lengthening shadows had on the crew's morale as their expedition became a desperate race against time.

To help ensure that the KM III crew could reach at least one cargo lander, Earth Control hurriedly dispatched two backups designated S 4 and S 5. After flights lasting 70 hours, they alighted south of KM III on the same side of the rift and ridges as the piloted lander. This should have made them easy to reach; however, they landed in terrain even more treacherous than that separating KM III from S 1 and S 2.

Meanwhile, Pešek's brave crew climbed and found a pass through Disappointment Ridge, then found places where they could enter the long rift and, after hiking some distance along its rocky, shadowed floor, climb out on its far side using ropes. They marked their way with red metal disks mounted on rods. At last reaching S 2, they activated its living quarters and unloaded tractor TK 2.

They were plagued by Moon suit oxygen regulators that had functioned flawlessly during tests on Earth and in Earth orbit, but which failed inexplicably whenever they passed into cold shadow on the Moon. The curious malfunction was at first life-threatening — it allowed exhaled carbon dioxide to build up in the suits, which probably accounted for AST's difficulties during the unsuccessful hike to S 1 — but through trial-and-error the crew made the oxygen regulator problem a mere persistent annoyance.

AST and CAP suffered injuries that left them unfit for heavy work, and all the men suffered rashes and sores from wearing their Moon suits for far longer than originally planned. As they hiked and labored for long hours, they were obliged to try to sleep in their suits on the lunar surface.

DOC was part of the three-man team that reached S 5 after a grueling hike through 10 miles of boulders and steep hillocks. They barely managed to unload tractor TK 5 before S 5 tilted on unsteady ground and toppled into an "abyss" beneath the lunar surface. Soon after their close brush with catastrophe, DOC called the Moon "a world of death" that could "not be underestimated for a minute."

Nevertheless, retrieval of TK 5 marked a turning point for the Moon explorers. Availability of TK 5 on the same side of the rift as KM III permitted the crew at last to devise a plan for refueling their spacecraft.

They would load 650-pound, six-foot-long propellant tanks from S 2 onto TK 2 by hand and transport them to the rift, then transfer the tanks to buckets hanging from an aerial tramway intended originally for unspecified selenological studies. After the tramway carried the propellant tanks over the rift, they would load them onto TK 5 for the slow, slippery climb over Disappointment Ridge to KM III.

TK 2 and TK 5 could each carry up to 20 propellant tanks at a time, and the tramway buckets could move 20 tanks across the rift in one hour. Twenty tanks had a mass of about 6.5 tons, so about six trips were required to transfer from S 2 the 40 tons of propellants KM III needed for return to Earth.

The challenges did not end - TK 2 became stuck, a rain of meteoroids damaged KM III's solar concentrator, the aerial tramway nearly collapsed into the rift and had to be moved, and KM III began again to list to one side as propellants filled its tanks - yet Pešek's intrepid lunar explorers won through. With the glaring Sun touching the horizon and small features of the landscape casting long shadows, KM III lifted off with just hours to spare.

It is worth noting that, in some respects, Pešek's lunar expedition plan in Log of a Moon Expedition resembles the Lunar Surface Rendezvous (LSR) Apollo mission mode the Jet Propulsion Laboratory (JPL) proposed in 1961-1962. Pešek's plan was, however, on a much larger scale. LSR aimed to accomplish Apollo lunar landings using technology derived from JPL's automated Surveyor soft-lander, which was under development at the time.

A robot lander transfers the last of three solid-propellant rocket motors to the Earth-return crew capsule lander using the extendible bridge truss method. The first lander to reach the site, equipped with a homing beacon and a TV camera, sits in the background at upper right. The cargo lander at lower left has transferred its rocket motor and withdrawn its extendible bridge truss, as has another cargo lander out of view to the right. Image credit: Jet Propulsion Laboratory/NASA.

In the LSR mode, several automated landers would touch down on the Moon tens of feet apart before any humans arrived. The first lander to reach the chosen landing site would carry science instruments, a TV camera, and a homing beacon.

After engineers and scientists used its data to certify the site as safe for further landings, a series of Surveyor-derived cargo landers would arrive. Three or four would each carry as cargo a solid-propellant rocket motor. After the last landed successfully, another lander, this time carrying an unmanned pressurized Earth-return crew capsule, would touch down at the site. The capsule would include seating for up to three astronauts, an Earth-atmosphere reentry heat shield, and parachutes.

Controllers on Earth would guide a small rover as it collected each solid-propellant rocket motor in turn and attached it to the lander bearing the crew capsule. Alternately, they would extend a bridge truss from each cargo lander in turn to transfer the solid-propellant motors. The rover method was considered more likely to succeed.

After JPL's lander/crew capsule combination was ready, an identical crew capsule on a Surveyor-derived lander would depart Earth bearing up to three astronauts. It would slow its descent by firing solid-propellant rocket motors identical to those attached to the lander/crew capsule on the Moon. With help from homing beacons, it would then use chemical-propellant vernier rockets to land near the waiting lander/crew capsule.

Following touchdown, the astronauts would transfer to their ride home and ignite its solid-propellant rocket motors to begin their return to Earth. Nearing Earth, they would cast off the lander and spent rocket motors and position their capsule for reentry.

Sources

Log of a Moon Expedition, Luděk Pešek, Alfred A. Knopf Publishers, 1969.

Man-to-the-Moon and Return Mission Utilizing Lunar-Surface Rendezvous, Technical Memorandum No. 33-53, P. Buwalda, W. Downhower, P. Eckman, E. Pounder, R. Rieder, and F. Sola, Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California, 3 August 1961.

"Man-on-the-Moon and Return Mission Utilizing Lunar-Surface Rendezvous," J. Small & W. Downhower, Jet Propulsion Laboratory; paper presented at the American Rocket Society Lunar Missions Meeting Held in Cleveland, Ohio, 17-19 July 1962.

Ludek Pesek: Space Artist (http://www.ludekpesek.ch/index.php - accessed 10 April 2018).

More Information

Space Race: The Notorious 1962 Proposal to Launch an Astronaut on a One-Way Trip to the Moon

Plush Bug, Economy Bug, Shoestring Bug (1961)

Around the Moon in 80 Hours (1958)

Around the Moon in 80 Hours (1958)

The Earth-Moon binary as imaged by the Near Earth Asteroid Rendezvous (NEAR) Shoemaker Discovery mission during its Earth gravity-assist flyby on 23 January 1998. Image credit: NASA.

On 29 July 1958, President Dwight Eisenhower signed into law the National Aeronautics and Space Act, which created the civilian National Aeronautics and Space Administration (NASA). Eisenhower saw NASA as a way of separating the serious military business of spy satellite and nuclear missile development from "stunts" aimed at responding to Soviet prestige victories in space. In the old General's view, such stunts included launching a man into Earth orbit.

In a presentation given the following month to the American Astronautical Society at Stanford University, Dandridge Cole and Donald Muir, engineers with The Martin Company in Denver, Colorado, detailed how NASA might launch humans around Earth's moon. First, however, they warned that the "Russians may have such a long lead. . .that they will have made landings on the [M]oon before. . .our first circumlunar flight." They predicted that the Soviet Union would be capable of a piloted circumlunar flight in 1963, four years before the United States. In a dig at President Eisenhower, Cole and Muir added that "on the technical side, at least, there seems to be no reason why this goal could not be accomplished [by the U.S.] by 1963."

They outlined a general plan of piloted spaceflight development. Within four years, Cole and Muir wrote, the first American would be launched into Earth orbit using a missile already under development. The same missile might then be used to launch components for a circumlunar spacecraft into Earth orbit. Alternately — and this was their preferred method — missiles might be clustered to form a single large rocket capable of launching the circumlunar spacecraft from Earth's surface on a direct path around the Moon.

The four-stage "Missile B" rocket would launch the circumlunar astronaut around the Moon. Image credit: The Martin Company.

The Martin engineers estimated that a 160,000-pound-thrust U.S. launch vehicle ("Missile A") could become available by 1963; to create their circumlunar launcher ("Missile B"), they proposed clustering four Missile A's to create a first stage capable of generating 610,000 pounds of thrust. Missile B's second stage would comprise a single Missile A, and its third and fourth stages would, respectively, comprise a 40,000-pound-thrust rocket and a 10,000-pound-thrust rocket.

Though a two-week circumlunar trip would require the least energy — and thus the smallest launch vehicle — Cole and Muir opted for a trip lasting three or four days. They did this to protect the astronaut's psychological health. "For one man alone in a tiny sealed capsule on a journey of 250,000 miles from the [E]arth," they explained, "the difference between three or four days and two weeks might approach infinity."

Reduced trip time also would slash the quantity of life-support consumables the pilot would need. The amount of energy required to reduce the trip time from two weeks to three or four days would be modest, they estimated, though reducing it still further would demand a prohibitive amount of energy — and thus an undesirably large launch vehicle.

The bucket-shaped circumlunar capsule would weigh 9000 pounds. Cole and Muir may have based its shape on nuclear warhead delivery systems under development at the time they wrote their paper.

The capsule's circumlunar path would have three parts. The outbound leg would require 35.4 hours. It would be followed by a 9.3-hour "hyperbola" past the Moon. The capsule would pass just 10 miles over the unknown farside hemisphere, where the "synthesizing power of the human brain [would] permit collection of more accurate and more meaningful data than could be obtained by photographic techniques alone."

The third leg of the mission, the 35.4-hour fall back to Earth, would mirror the outbound leg. The circumlunar voyager would be treated to a magnificent view of Earth rising over the lunar horizon as he began his journey home.

Cutaway of Cole and Muir's circumlunar capsule showing the water-filled "tub" for protecting the astronaut from high deceleration during Earth-atmosphere reentry. A variant of the circumlunar capsule would serve as the first lunar lander. Image credit: The Martin Company.

The heat shield for high-speed Earth-atmosphere reentry would weigh just 500 pounds, Cole and Muir estimated. As Earth filled the capsule's view ports, the pilot's "bathtub-type" couch would fill with water to cushion him from reentry deceleration. A lid with a window would prevent the water from escaping in zero-G before deceleration commenced. Cole and Muir wrote that, because "the water would be needed only in the last phase of the trip, it could be reserve drinking or washing water." Despite the potential weight savings, they hesitated "to suggest that it might be water. . .already used for drinking or washing."

The capsule would enter Earth's atmosphere blunt nose first. As deceleration began, the bathtub couch would pivot so that the pilot faced the capsule's flat aft end. This would cause him to feel capsule deceleration through his back, enabling him to withstand greater sustained deceleration loads.

After a fiery atmosphere reentry, the capsule would deploy fins for steering. Landing would be by parachute at sea or on U.S. soil near a waiting recovery crew.

Cole and Muir expected that the piloted circumlunar journey would merely open the door to lunar exploration. A series of automated lunar landings would soon follow it. Some would deliver automated scientific instruments that would explore the lunar environment, while others would stockpile propellants and supplies on the surface.

Toward the end of the 1960s decade, the same multi-part "Missile B" rocket design that launched the circumlunar flight would launch a piloted lunar lander. The pre-landed supplies and propellants would, Cole and Muir wrote, enable use of a variant of the circumlunar spacecraft as a small, low-cost lunar lander. Landers would set down on the Moon with nearly empty propellant tanks, refuel using the pre-landed propellants, and draw on pre-landed supplies to enable ever-longer surface stays. A temporary lunar base would be established by 1970, and permanent bases permitting "extensive exploration of the major areas of the [M]oon's surface" would follow soon after.

Cole and Muir ended their paper with rousing words. "Time may well prove," they wrote, "that the man who climbs out of [the circumlunar] capsule to receive the cheers of the recovery crew. . .made a voyage of greater importance to the human race than that of Columbus."

Source

"Around the Moon in 80 Hours," D. Cole and D. Muir, Advances in Astronautical Sciences, Volume 3, Proceedings of the Western Regional Meeting of the American Astronautical Society, 18-19 August 1958, pp. 27-1 through 27-30, 1958.

More Information

"He Who Controls the Moon Controls the Earth" (1958)

Plush Bug, Economy Bug, Shoestring Bug, (1961)

Harold Urey and the Moon (1961)

Space Race: The Notorious 1962 Proposal to Launch an Astronaut on a One-Way Trip to the Moon (1962)

Creation of an Artificial Lunar Atmosphere (1974)

The Lunar Module included a descent stage for descent from lunar orbit and lunar surface landing and an ascent stage for return to lunar orbit. This image, captured from television transmitted to Earth by the parked Apollo 16 Lunar Roving Vehicle, shows the moment the ascent stage engine of the Lunar Module Orion ignited. Hot gas from the engine plume blasted pieces of thermal insulation for kilometers in all directions. Image credit: NASA.

On the Moon, nothing is a valuable resource. At the lunar surface, where astronauts hop and rovers rove, the environment is a nearly pure vacuum. The total amount of gas spread over the Moon's entire surface — which has an area greater than that of Africa — is less than 50 metric tons. This makes the Moon a potentially important site for high-tech industrial processes.

The Moon owes its lack of atmosphere to the Sun. Solar wind and ultraviolet light ionize gas atoms, making them susceptible to transport by the interplanetary magnetic field. Half the atoms escape into space and the rest are driven into the lunar surface material.

In 1974, in the pages of the prestigious publication Nature, Richard Vondrak of NASA's Goddard Research Center in Greenbelt, Maryland, pointed out that lunar vacuum "is a fragile state that could be modified by human activity." He urged that it be "treated carefully if it is to be preserved."

At the time Vondrak wrote, his concern was not wholly academic. In the early 1970s, not a few engineers within NASA expected that the Space Shuttle would lead to a return to the Moon in the 1980s. A lunar outpost where astronauts would conduct resource extraction and beneficiation experiments and test prototype high-vacuum industrial processes would follow soon after.

Vondrak estimated that each of the six Apollo landing missions had doubled the mass of the Moon's atmosphere. He cited two main sources of Moon pollution: life support gases released from Apollo space suits and the Apollo Lunar Module (LM) cabin and rocket exhaust from the Apollo LM rocket motors. The lunar atmosphere returned to normal after a month, however, leading Vondrak to assert that "small lunar colonies" and modest mining would pose "no lasting hazard to the lunar environment."

If, however, more "vigorous" human activity pumped up the lunar atmosphere to a mass of one billion metric tons, solar wind and ultraviolet light would be unable to ionize more than its outermost fringe. The thin lunar atmosphere would then persist for centuries even if no more gas were added, Vondrak wrote.

Vondrak looked briefly at the far-out prospect of creating an Earth-density atmosphere on the Moon by vaporizing oxygen-rich lunar dirt using nuclear blasts. At the time he wrote, the U.S. nuclear arsenal numbered about 28,000 warheads. He estimated that generating an Earth-density atmosphere would require roughly 10,000 times more warheads than the U.S. possessed. Not surprisingly, Vondrak judged this approach to be impractical.

Source

"Creation of an Artificial Lunar Atmosphere," Richard R. Vondrak, Nature, Vol. 248, 19 April 1974, pp. 657-659.

More Information

Rocket Belts and Rocket Chairs: Lunar Flying Units

"A Continuing Aspect of Human Endeavor": Bellcomm's January 1968 Lunar Exploration Plan

Chronology: Failure Was an Option 1.0

Image credit: NASA.

Periodically, I write a post in which I list in chronological order links to posts in this blog which I originally presented in no particular order. History is, after all, in large measure about chronology, so these omnibus posts are meant to aid understanding. This post brings together posts with the label "failure was an option" and is offered as a memorial to the 17 persons who have died on board NASA spacecraft.

The end of January and beginning of February is a time of remembrance for NASA piloted spaceflight. On 27 January 1967, astronauts Gus Grissom, Edward White, and Roger Chaffee lost their lives in the Apollo 1 fire. On 28 January 1986, the crew of Space Shuttle mission STS-51L (Dick Scobee, Michael Smith, Ellison Onizuka, Judith Resnik, Ron McNair, Gregory Jarvis, and Christa McAuliffe) perished after the Orbiter Challenger disintegrated 73 seconds after launch. On 1 February 2003, the STS-107 crew (Rick Husband, William McCool, Michael Anderson, Kalpana Chawla, David Brown, Laurel Clark, and Ilan Ramon) died when the Orbiter Columbia broke up during reentry after a nearly 16-day mission in Earth orbit.

Piloted spaceflight has never been routine, though sometimes, for reasons that have little to do with best practices in space engineering, it has been unwisely treated as such. Throughout the history of U.S. piloted spaceflight, however, NASA and its contractors typically have tried to anticipate possible malfunctions and, where possible, develop procedures for dealing with them.

What If an Apollo Saturn Rocket Exploded on the Launch Pad? (1965)

What If Apollo Astronauts Could Not Ride the Saturn V Rocket? (1965)

North American Aviation's 1965 Plan to Rescue Apollo Astronauts Stranded in Lunar Orbit

What If an Apollo Lunar Module Ran Low on Fuel and Aborted Its Moon Landing? (1966)

If an Apollo Lunar Module Crashed on the Moon, Could NASA Investigate the Cause? (1967)

What If Apollo Astronauts Became Marooned in Lunar Orbit? (1968)

A CSM-Only Back-Up Plan for the Apollo 13 Mission to the Moon (1970)

What If a Crew Became Stranded On Board the Skylab Space Station? (1972)

What If a Space Shuttle Orbiter Had to Ditch? (1975)

George Landwehr von Pragenau's Quest for a Stronger, Safer Space Shuttle (1984)

What If a Shuttle Orbiter Struck a Bird? (1988)

NASA's 1992 Plan to Land Soyuz Space Station Lifeboats in Australia

Alternate History of the Space Age 1.0

Lunar Truck. Image credit: Grumman.

As long-time readers of this blog know, occasionally I get creative and change history. Not in my history posts, if I can help it, but through alternate history posts. Some are silly, some not, and some (most?) are brazen exercises in wishful thinking. All, however, are entertaining to a greater or lesser degree (or so my readers seem to think) and maybe even a bit instructive, since I try to make them as realistic as possible.

Below is a list of my spaceflight alternate history posts so far. Have fun.

Dreaming a Different Apollo, Part One: Shameless Wishful Thinking

Dreaming a Different Apollo, Part Two: Naming Names

Jimmy Carter's Space Shuttle

Victory Lap

Mirror Universe: Star Trek as an Exemplar of Space Age Popular Culture

Pluto: An Alternate History

What If a Shuttle Orbiter Struck a Bird? (1988)

Final approach: the Shuttle Orbiter Discovery lands on the Shuttle Landing Facility at Kennedy Space Center, Florida, at the end of its longest mission (STS-131, 5-20 April 2010). Image credit: NASA.

The first NASA astronaut to die in the line of duty was U. S. Air Force Captain Theodore Freeman. Little known today, Freeman was a member of the third astronaut selection group, which NASA introduced to the world on 18 October 1963. The group included 10 astronauts who would become famous — Michael Collins, Edwin Aldrin, Alan Bean, David Scott, Russell Schweickart, William Anders, Eugene Cernan, Walter Cunningham, Donn Eisele, and Richard Gordon — and three besides Freeman who would perish before reaching orbit — Clifton Williams, Roger Chaffee, and Charles Bassett. Of the seven pre-Shuttle NASA astronaut groups, Group 3 experienced more pre-flight astronaut deaths than any other.

The astronauts had at their disposal Northrop T-38 Talon supersonic training aircraft. They used them in two basic ways: for training sorties to accumulate flight time so that they could keep their piloting skills well honed and retain their flight status, and as readily available, speedy transportation to NASA and contractor facilities and training sites across the United States. Transportation flights also contributed to the flight time requirement.

On 31 October 1964, 34-year-old Freeman took off alone in a T-38 from Ellington Air Force Base, located between downtown Houston, Texas, and NASA's Manned Spacecraft Center (MSC). He began his training sortie by flying over MSC, then out over Clear Lake and Galveston Bay.

NASA's Third Astronaut Group. Theodore Freeman is in the back row, fourth from left. Image credit: NASA.

As he returned to Ellington, a flock of Canadian geese took wing to one side of his flight path. As he made a turn, the flock rose up around his T-38, and one bird struck and shattered the plane's plexiglass forward canopy. Plexiglass shards entered the jet's twin engines through their air intakes. Moments later, the engines began to fail.

The eight-pound goose did not enter the T-38's intakes, though some sources report that it did. In fact, after striking the canopy, it struck the plane's rear seat, then spun away along the jet's upper fuselage.

Freeman tried to line up with an Ellington runway, but the engines flamed out and his plane began a steep dive at low altitude. He ejected, but before his parachute had time to open he struck the ground and was killed.

In October 1983, nearly 20 years after Freeman's untimely death, The Christian Science Monitor published a puff piece on NASA's efforts to keep wild pigs and alligators off the 15,000-foot-long, 300-foot-wide Shuttle Landing Facility (SLF) runway at Kennedy Space Center (KSC) in Florida. The story was timely because NASA aimed to achieve its first Orbiter landing at the SLF in January 1984. The space agency had planned to land Challenger at the SLF at the end of mission STS-7 on 24 June 1983, but had to divert it to Edwards Air Force Base (EAFB) in California after KSC became fogged in.

The north end of the SLF is about a mile from the Visitor Center for the Merritt Island National Wildlife Refuge (MINWR). MINWR and KSC both owe their origin to President John F. Kennedy's 25 May 1961 "Moon Speech." In 1962-1963, NASA acquired more than 140,000 acres of orange groves, swamp, and beaches to create a safety buffer around its Apollo Saturn V launch pads and other facilities. As landowners moved out, sometimes grudgingly, wildlife moved in.

On 28 August 1963, the space agency and the U.S. Fish and Wildlife Service agreed that the latter would manage the roughly 90% of KSC that NASA did not actively use. The interagency agreement assumed that KSC activities would increase over the course of the 1960s and 1970s and that its facilities would steadily expand. Apollo-era construction leveled off in 1966-1967, however.

Major facilities expansion did not begin again at KSC until April 1974, when the Morrison-Knudsen Company began work on the $22-million-dollar SLF. The facility, modeled on flight research runways at EAFB, was completed in 1976. It became KSC's airport, supporting astronaut T-38s, Gulfstream II Shuttle Training Aircraft, and other planes and helicopters. The first space-worthy Orbiter, Columbia, arrived at the SLF atop a 747 carrier aircraft in March 1979.

The Shuttle Landing Facility. Image credit: NASA.

A NASA spokesman told The Christian Science Monitor's reporter that KSC and MINWR played host to "all kinds of bald eagles, vultures, lots of brown pelicans, and ducks in winter." This was, however, not of great concern; the Shuttle Orbiter was a glider, he explained, so lacked air intakes that might ingest birds.

The Christian Science Monitor reporter wrote that the Orbiter had "triple-strength windows." This was a reference to the design of the six windows making up the flight deck windshield; each was three panes thick, with empty spaces between the panes. The outermost pane, the "thermal" pane, was attached to the fuselage structure; the innermost pane, the "pressure" pane, was attached to the crew cabin structure. Between these, also attached to the crew cabin structure, was a thick "redundant" pane.

The article affected an almost humorous tone as it described measures aimed at keeping alligators and wild pigs off the SLF. It seemed impossible that the Space Shuttle, a pinnacle of U.S. technological know-how, could ever be harmed by mere animals. Its author did suggest, however, that running over alligators basking in the Sun on the SLF runway might damage the Orbiter's "delicate landing gear."

On its second try, at the end of mission STS 41-B in February 1984, Challenger glided to a safe landing on the SLF runway. NASA hailed the landing, little more than five miles from the launch pad Challenger had left just eight days before, as a major step toward routine Shuttle flights and Shuttle launch rates of up to 25 per year.

A little less than two years later, on 28 January 1986, Challenger disintegrated 73 seconds after liftoff from KSC's Pad 39B, killing its seven-person crew. The disaster revealed that the Shuttle stack — twin reusable Solid Rocket Boosters, expendable External Tank, and reusable delta-winged Shuttle Orbiter — was much less robust than many had assumed.

Under intense scrutiny, NASA commenced a wide-ranging examination of Space Shuttle systems and operations. The U.S. civilian space agency soon found that many of its comfortable assumptions were incorrect.

Shuttle windshield: the Orbiter Endeavour during mission STS-123 (11-27 March 2008). Image credit: NASA.

Karen Edelstein, with NASA's Johnson Space Center, and Robert McCarty of the Wright Aeronautical Laboratories at Wright-Patterson Air Force Base in Ohio, reported on results of their study of bird impacts on the Orbiter windshield. They determined that, far from being triple-strength, it was "a poor barrier to bird impacts."

In fact, computer modeling using a refined version of the U. S. Air Force Material and Geometrically Nonlinear Analysis (MAGNA) program showed that, in every case, a four-pound bird — for example, a typical turkey vulture — would penetrate all three windshield panes in less than a second and enter the flight deck if the Orbiter were moving above an indeterminate speed between 150 knots (172 miles per hour) and 175 knots (201 miles per hour). They noted that the Orbiter traveled at up to 355 knots (408 miles per hour) as it fell past 10,000 feet and 195 knots (224 miles per hour) as its rear wheels touched the SLF runway.

This meant that at no time during descent through altitudes where birds fly did the Orbiter's windshield provide protection from bird strikes. In fact, the crew on the flight deck remained vulnerable until about the time the Orbiter's nose gear touched concrete.

Edelstein and McCarty did not examine in detail a bird impact leading to a partial window failure; for example, broken thermal and redundant panes and an intact pressure pane. This scenario was expected to occur at speeds as low as 150 knots. One may speculate that at the very least a partial failure would make the affected window essentially opaque; it might also create extra drag, altering the handling characteristics of the Orbiter.

A turkey vulture. Its wingspan is about six feet. Image credit: Wikipedia.

They noted that, short of a major redesign, there was little NASA could do to beef up the Orbiter windows. They urged designers of future space planes to seek materials more sturdy than glass when designing their windshields.

The Edelstein and McCarty paper did not lead to a major Orbiter redesign or new Orbiter window materials; NASA's allotted budget would not extend that far. Instead, the space agency redoubled its efforts to scare birds away from the SLF. Mostly it relied on loud noises.

For a time in the mid-1990s, however, KSC seriously considered putting falconers on its payroll. A June 1994 study noted that falcons had been used intermittently since the 1940s to kill or scare away birds at airfields in the U.K., the Netherlands, Spain, France, Canada, and the United States.

The study determined, however, that most of the more than 300 bird species that spent at least part of the year in MINWR had little experience with falcons, so were unlikely to be frightened by them. Falcons, for their part, were likely to be confused by wading birds such as herons and egrets.

The birds most threatening to Orbiters and other aircraft at the SLF, the 1994 study found, were various species of vulture. These were too large and numerous for falcons to tackle. It noted that groups of up to 30 individuals were frequently found around a single roadkill and that a "roost" of about 300 vultures had become established on the SLF runway's southern approach path.

The vultures, which weighed up to five pounds, took to the skies to ride thermals over KSC beginning in mid-morning. Mostly they glided lazily between 150 and 1800 feet above the ground. The air currents rising off the 526-foot-tall Vehicle Assembly Building were especially attractive to them. If the birds smelled a carrion buffet, however, they could fly rapidly, thwarting efforts to track and deter them. Loud noises, effective in driving away most other birds, were of little concern to vultures.

During the mid-morning launch of the Orbiter Discovery at the start of mission STS-114 on 26 July 2005, a vulture collided with the External Tank before the Shuttle stack cleared the Pad 39A launch tower. The bird probably weighed more than twice as much as the 1.7-pound chunk of External Tank foam insulation that had struck and breached Columbia's left wing leading edge on 16 January 2003, 82 seconds into mission STS-107. The foam chunk was estimated to have been moving at about 525 miles per hour when it hit the wing.

During Earth-atmosphere reentry on 1 February 2003, hot gases entered Columbia's left wing through the breach and rapidly destroyed its aluminum internal structure. NASA's oldest Orbiter broke up, killing the seven-member STS-107 crew.

Though the low-speed bird impact caused no obvious damage to the External Tank, NASA took notice because it occurred during launch of the first Shuttle mission since STS-107. The vulture might easily have struck a more vulnerable part of the Shuttle stack, or have struck it at a higher altitude, after the Shuttle had gained speed. KSC managers decided to apply SLF bird control techniques to the twin Shuttle launch pads. They also adopted a launch-day vulture "trap-and-release" policy.

By 2009, KSC's Bird Abatement Program relied on quick removal of roadkill to eliminate a major scavenger food source and pare down vulture numbers, bird detection radar and cameras, sirens, shotguns firing blanks and whistlers, and 25 liquid-propane-fueled "cannons." Installed along the SLF in 2007, the noise-producing cannons could be set off from the SLF runway control tower or by bird observers on the ground. They could also be set to fire automatically at random times and in random directions. Despite these measures, the risk to the Shuttle from bird strikes persisted until the Orbiter Atlantis rolled to a stop on the SLF runway at the end of STS-135, the final Shuttle mission, in July 2011.

Sources

"Space Shuttle Orbiter Windshield Bird Impact Analysis," ICAS-88-5.8.3, K. Edelstein and R. McCarty, Proceedings of the 16th International Council on Aeronautical Sciences Congress held in Jerusalem, Israel, 28 August-2 September 1988, Volume 2, pp. 1267-1274.

A Review of Falconry as a Bird Control Technique With Recommendations for Use at the Shuttle Landing Facility, John F. Kennedy Space Center, Florida, U.S.A., NASA Technical Memorandum 110142, V. Larson, S. Rowe, D. Breininger, and R. Yosef, June 1994.

"History of the Shuttle Landing Facility at Kennedy Space Center," E. Liston and D. Elliot; paper presented at The (40th) Space Congress in Cocoa Beach, Florida, 28 April-2 May 2003.

Fallen Astronauts: Heroes Who Died Reaching for the Moon, Revised Edition, C. Burgess and K. Doolan with B. Vis, University of Nebraska Press, 2016, pp. 1-45.

"NASA Tries To Keep The Hogs and 'Gators Off the Shuttle's Runway," G. Klein, The Christian Science Monitor, 12 October 1983 (https://www.csmonitor.com/1983/1012/101225.html - accessed 17 December 2017).

"It's a Jungle Out There!" L. Herridge, 26 June 2006 (https://www.nasa.gov/mission_pages/shuttle/behindscenes/roadkill.html - accessed 14 December 2017).

"Bye, Bye, Birdies," C. Mansfield, 30 June 2006 (https://www.nasa.gov/mission_pages/shuttle/behindscenes/avian_radar.html - accessed 16 December 2017).

"Bird Team Clears Path for Space Shuttles," L. Herridge, 12 August 2009 (https://www.nasa.gov/mission_pages/shuttle/behindscenes/clearbirds.html - accessed 14 December 2017).

More Information

Where to Launch and Land the Space Shuttle? (1971-1972)

What If a Shuttle Orbiter Had to Ditch? (1975)

What Shuttle Should Have Been: NASA's October 1977 Space Shuttle Flight Manifest

X-15: Lessons for Reusable Winged Spaceflight (1966)

An X-15 rocket plane separates from its B-52 carrier aircraft. During this 9 November 1961 flight, the 45th in the X-15 series, U.S. Air Force Major Robert White piloted X-15 No. 2 to a world-record speed of Mach 6.04 (4093 miles per hour). It was the first time a piloted aircraft exceeded Mach 6. Image credit: NASA.

The X-15 is a strong contender for the title of "Everyone's Favorite X-plane." Conceived in the 1952-1954 period, before Sputnik (4 October 1957) and the birth of NASA (1 October 1958), the North American Aviation-built rocket plane was intended to pioneer the technologies and techniques of piloted hypersonic flight — that is, of flight faster than Mach 5 (five times the speed of sound).

Between 1959 and 1968, three X-15 rocket planes, two modified B-52 bombers, and a dozen pilots took part in joint U.S. Air Force/NASA X-15 research missions. Before the start of each mission, an X-15 was mounted on a pylon attached to the underside of a wing of a B-52 carrier aircraft at Edwards Air Force Base, California. Wearing a silver pressure suit, a single pilot boarded the 50-foot-long X-15 as it hung from the pylon, then the B-52 taxied and took off from a runway.

Early X-15 missions were "captive" flights, meaning that the rocket plane stayed attached to the B-52, or gliding flights, meaning that it carried no propellants and relied on its wings, which spanned only 22 feet, to make a controlled — though fast and steep — descent to a landing. Early powered flights used stand-in rocket engines taken from earlier X-planes. By late 1960, however, the X-15's throttleable 600,000-horsepower XLR99 rocket engine was ready. The engine was designed to burn the nine tons of anhydrous ammonia fuel and liquid oxygen oxidizer in the X-15's tanks in about 90 seconds at full throttle.

During high-speed flight and Earth atmosphere reentry, the X-15 compressed the air in front of it, generating temperatures as high as 1300° Fahrenheit on its nose and wing leading edges. The rocket plane's designers opted for a "hot structure" approach to protecting it from aerodynamic heating through most of its career. An outer skin made of Inconel X, a heat-resistant nickel-chromium alloy, covered an inner skin of aluminum and spun glass, which in turn covered a titanium structure with a few Inconel X parts. Heat caused the skin and structure to expand, warp, and flex, but they would return to their original shapes as they cooled. The X-15's cockpit temperature could reach 150° Fahrenheit, but the pilot usually remained cool in his pressure suit.

Most missions followed two basic profiles. "Speed" missions saw the rocket plane level off at about 101,000 feet and push for ever-higher Mach numbers. The X-15 reached its top speed — Mach 6.72, or about 4520 miles per hour — during the 188th flight of the series on 3 October 1967 with Air Force Major William "Pete" Knight at the controls.

Knight flew X-15A-2, the former X-15 No. 2, which had rolled over during an abort landing on 9 November 1962, seriously injuring its pilot, John McKay. When NASA and the Air Force rebuilt X-15 No. 2, they modified its design to enable faster flights. One modification was the addition of a replaceable ablative heat shield so that it could withstand the higher temperatures that came with faster speeds. Ablative heat shields are designed to char and break away, carrying away heat.

For "altitude" missions, the X-15 climbed steeply until it exhausted its propellants, then arced upward, unpowered. X-15 reached its peak altitude — 354,200 feet (almost 67 miles) above the Earth's surface — on 22 August 1963, with NASA pilot Joseph Walker in the cockpit.

During altitude missions, the pilot experienced several minutes of weightlessness as the X-15 climbed toward the high point of its trajectory, above 99% of the atmosphere, then fell back toward Earth. Aerodynamic control surfaces (for example, ailerons) could not work while the X-15 soared in near-vacuum, so the space plane included hydrogen peroxide-fueled attitude-control thrusters so that the pilot could orient it for reentry.

It was during an altitude mission that the X-15 program suffered its only pilot fatality. On 15 November 1967, Major Michael Adams piloted X-15 No. 3 to 266,000 feet despite an electrical problem that made control difficult. During descent, Adams lost control of the space plane, which went into a flat spin at Mach 5, then an upside-down dive at Mach 4.7. Adams might have recovered control at that point, but then an "adaptive" flight control system malfunctioned, thwarting maneuvers that might have damped out excessive pitch oscillations and compensated for increasing atmospheric density. The X-15 broke apart at about 65,000 feet.

Flights of early rocket-powered X planes, such as the first aircraft to break the sound barrier, the Bell X-1, took place over Edwards Air Force Base, but the X-15 needed more room for its speed and altitude flights. In both powered X-15 mission profiles, the B-52 released the X-15 about 45,000 feet above northern Nevada with its nose pointed southwest toward its landing site on Edwards dry lake bed. Two radio relay stations and six emergency landing sites on dry lake beds were established along the X-15 flight path. Adams might have landed on Cuddeback dry lake bed, 37 miles northeast of Edwards, had he regained control of X-15 No. 3.

This NASA cutaway of the X-15 displays the aircraft's XLR99 engine, weight-saving aft skids, propellant tanks, wing, fin, and fuselage structure, cockpit, and forward landing gear. The lower tail fin was necessary for flight stability, but got in the way during landing, so was designed to drop away during approach.

NASA's Project Mercury, which began officially on 6 October 1958, opted for a different approach to aerodynamic heat management: a bowl-shaped single-use ablative heat shield. As piloted Mercury capsule flights commenced (5 May 1961) and President John F. Kennedy put NASA on course for the Moon (25 May 1961), public attention shifted away from the X-15 and Edwards Air Force Base and toward Mercury, Apollo, and Cape Canaveral, Florida. X-15 research planes continued to fly, however, pushing the hypersonic flight envelope well past their original design limits.

In the same period, some within NASA planned Earth-orbiting space stations. Before Kennedy's Moon speech, a space station was seen as the necessary first step toward more advanced space activities. It would serve as a laboratory for exploring the effects of space conditions on astronauts and equipment and as a jumping-off place for lunar and interplanetary voyages. 

Station supporters often envisioned that it would reach orbit atop a two-stage Saturn V rocket, and that reusable spacecraft for logistics resupply and crew rotation would make operating it affordable. After the Moon speech, station proponents hoped that, once Kennedy's politically motivated Moon goal was reached, piloted spaceflight could resume its "proper" course by shifting back to space station development.

In November 1966, James Love and William Young, engineers at the NASA Flight Research Center at Edwards Air Force Base, completed a brief report in which they noted that the reusable suborbital booster for a reusable orbital spacecraft would undergo pressures, heating rates, and accelerations very similar to those the X-15 experienced. They acknowledged that the X-15, with a fully fueled mass of just 17 tons, might weigh just one-fiftieth as much as a typical reusable booster. They nevertheless maintained that X-15 experience contained lessons applicable to reusable booster planning.

Love and Young wrote that some space station planners expected that a reusable booster could be launched, recovered, refurbished, and launched again in from three to seven days. The X-15, they argued, had shown that such estimates were wildly optimistic. The average X-15 refurbishment time was 30 days, a period which had, they noted, hardly changed in four years. Even with identifiable procedural and technological improvements, they doubted that an X-15 could be refurbished in fewer than 20 days.

At the same time, Love and Young argued that the X-15 program had demonstrated the benefits of reusability. They estimated that refurbishing an X-15 in 1964 had cost about $270,000 per mission. NASA and the Air Force had accomplished 27 successful X-15 flights in 1964. The cost of refurbishing the three X-15s had thus totaled $7.3 million.

Love and Young cited North American Aviation estimates when they placed the cost of a new X-15 at about $9 million. They then calculated that 27 missions using expendable X-15s would have cost a total of $243 million. This meant, they wrote, that the cost of the reusable X-15 program in 1964 had amounted to just 3% of the cost of building 27 X-15s and throwing each one away after a single flight.

NASA test pilot Neil Armstrong flew the X-15 seven times in 1960-1962. Armstrong became a member of NASA Astronaut Group 2 ("The New Nine") in September 1962. He orbited the Earth as commander of Gemini 8 (March 1966) and became the first man to set foot on the Moon during Apollo 11 (July 1969). Another X-15 pilot, Joseph Engle, became a member of NASA Astronaut Group 5 in April 1966. Engle flew the Orbiter Enterprise during Space Shuttle Approach and Landing Test (ALT) flights in 1977, commanded Columbia for mission STS-2 in November 1981, and commanded Discovery for mission STS 51-I in August-September 1985. Image credit: NASA.

The last X-15 flight, the 199th in the series, took place on 24 October 1968. Flight experience gained and hypersonic flight data collected during the nine-year program contributed to the development of the U.S. Space Shuttle, though not exactly as Love and Young had envisioned.

When, in 1968, NASA Headquarters management first floated Space Station/Space Shuttle as the space agency's main post-Apollo piloted program, the Shuttle was conceived as a reusable piloted orbiter vehicle with a reusable piloted suborbital booster — that is, the design that Love and Young had assumed. By late 1971, however, funding limitations forced NASA to opt instead for a semi-reusable booster stack comprising an expendable External Tank and twin reusable solid-propellant Solid Rocket Boosters.

The space agency was also obliged to postpone its Space Station plans at least until after the Space Shuttle became operational. Saturn V was on the chopping block, so the semi-reusable Shuttle would be used to launch the Station as well as to resupply it and rotate its crews.

Shuttle Orbiter Columbia first reached Earth orbit on 12 April 1981, but no Orbiter visited a space station until Discovery rendezvoused with the Russian Mir station on 6 February 1995 during mission STS-63. The first Shuttle Orbiter to dock with a station — again, Russia's Mir — was Atlantis during mission STS-71 (27 June-7 July 1995).

Sources

Survey of Operation and Cost Experience of the X-15 Airplane as a Reusable Space Vehicle, NASA Technical Note D-3732, James Love and William Young, November 1966.

"I Fly the X-15," Joseph Walker and Dean Conger, National Geographic, Volume 122, Number 3, September 1962, pp. 428-450.

Hypersonics Before the Shuttle: A Concise History of the X-15 Research Airplane, Monographs in Aerospace History No. 18, Dennis R. Jenkins, NASA, June 2000.

More Information

Space Station Resupply: The 1963 Plan to Turn the Apollo Spacecraft Into a Space Freighter

McDonnell Douglas Phase B Space Station (1970)

From Monolithic to Modular: NASA Establishes a Baseline Configuration for the Shuttle-Launched Space Station (1970)

Where to Launch and Land the Space Shuttle? (1971-1972)

After Venus: Pioneer Mars Orbiter with Penetrators (1974)

Pioneer Venus Orbiter (PVO) in Venus Orbit. The Pioneer Mars Orbiter (PMO) would have been based on this design. Image credit: NASA.

The name "Pioneer" was applied to several different spacecraft designs, all of which were meant to spin to create gyroscopic stability. The first U.S. Moon probe, launched by the Air Force in August 1958, bore the name. Though Pioneers 0 through 3 failed, Pioneer 4 flew by the moon at a distance of about 58,000 kilometers in March 1959. It became the first U.S. spacecraft to escape Earth's gravity and enter orbit around the Sun.

Pioneer 5 (March 1960), a unique design, was a pathfinder for future NASA interplanetary missions. Managed by NASA's Ames Research Center (ARC), it set a new record by transmitting until it was 36.2 million kilometers from Earth.

The Pioneer series seemed to draw to a close. In 1965, however, NASA ARC applied the name to its drum-shaped interplanetary "weather stations." The first, Pioneer 6, entered solar orbit between Earth and Venus in December 1965, where it monitored magnetic fields and radiation. Pioneers 7, 8, and 9 performed similarly prosaic (and generally little noticed) missions.

The first Pioneer design included a solid-propellant rocket motor on top; this was intended to slow the spacecraft so that the moon's gravity could capture it into lunar orbit. Pioneer 0, launched under U.S. Air Force auspices, was lost when its Thor-Able booster exploded 77 seconds after launch. Pioneers 1 and 2, launched under NASA auspices, also failed to reach lunar orbit, though the former attained a record altitude of 113,781 kilometers and returned useful data before falling back to Earth (October 1958). Image credit: NASA.

NASA's Pioneer 3 and 4 lunar flyby spacecraft were launched on Redstone-derived Juno II rockets. Booster failure doomed Pioneer 3, but Pioneer 4, shown here attached to its small solid-propellant upper stage, performed a distant lunar flyby. Image credit: NASA.

Pioneer 5, intended originally as a Venus probe set for launch in June 1959, was launched instead in March 1960 as a pathfinder for subsequent NASA planetary missions. Image credit: NASA.

Pioneers 6 through 9 were drum-shaped spacecraft that measured "space weather" conditions in interplanetary space near Earth's orbit. Image credit: NASA.

The name regained star status when Pioneer 10 left Earth in March 1972. It became the first spacecraft to brave the Asteroid Belt and fly past Jupiter. Pioneer 11 launched in April 1973, bound for Jupiter and Saturn. It went silent in 1995. Pioneer 10 sent its last signal from beyond Pluto in 2003.

The final Pioneer launches occurred in 1978. The Pioneer Venus Multiprobe spacecraft dropped four instrumented capsules on Venus, while Pioneer Venus Orbiter (PVO) surveyed the planet until 1992. The latter was informally designated Pioneer 12 and the former Pioneer 13.

Pioneer 10 and Pioneer 11, the only nuclear Pioneers, were Earth's first probes to traverse the Asteroid Belt and voyage through the outer Solar System. Image credit: NASA.

Pioneer Venus Multiprobe deploys its one large and three small atmosphere probes. Against expectations, two probes survived landing and return data from the surface of Venus. No other U.S. spacecraft has landed intact on Venus. Image credit: NASA.

If NASA ARC, the Planetary Programs Division of the NASA Office of Space Science, and Hughes Aircraft had had their way, the Pioneer name might also have been applied to a Mars spacecraft. In a 1974 report prepared on contract to NASA ARC, Hughes described a Pioneer Mars Orbiter (PMO) derived from the Hughes PVO spacecraft design. The PMO mission, set for launch in 1979, was intended as a follow-on to the twin Viking missions, which were scheduled to leave Earth in 1975 and seek life on Mars in 1976.

Hughes described the PVO upon which the PMO would be based as drum 2.5 meters in diameter and 1.2 meters tall with a 3.3-meter antenna mast on top and a solid-propellant Venus orbit insertion motor on the bottom. The company then cited differences between the PMO and PVO designs: for example, PMO's orbit insertion motor would need to be larger since it would arrive at Mars traveling faster than PVO would at Venus. In addition, PMO would operate in Mars orbit, about twice as far from the Sun as Venus, so solar cells would entirely cover its sides so that they could make enough electricity to operate the spacecraft's systems. PVO would operate in Venus orbit, so it would need to be only partly covered with solar cells.

The most obvious difference between the PVO and PMO designs were the Mars spacecraft's six 2.3-meter-long, 0.3-meter-diameter penetrator launch tubes. These would replace PVO's science instruments; apart from unspecified instruments in the penetrators, PMO would carry no science payload.

PMO, like PVO, would leave Earth on an two-stage Atlas-Centaur rocket. Because PMO would weigh more than PVO (1091 kilograms versus 523 kilograms), however, it would need a solid-propellant third stage to complete Earth escape. To make room for the third stage and penetrators, PMO's conical launch shroud would be 0.8 meters longer than its PVO counterpart.

PMO would need to reach Mars on 7 September 1980 so that its Mars orbit insertion motor could place it in its planned Mars orbit. To reach the planet on that date, PMO would need to depart Earth during one of 10 consecutive daily launch opportunities starting on 28 October 1979. 2 November 1979 would be the nominal launch date. The launch opportunities would only last from 10 to 15 minutes each.

The Centaur second stage would place PMO into a low-Earth orbit, then would ignite again 30 minutes later to begin pushing the spacecraft out of Earth orbit. The third-stage motor would then ignite to place PMO on course for Mars. PMO would weigh 1069 kilograms after third-stage separation. Launch on 2 November 1979 would yield a 310-day Earth-Mars transfer.

Following third-stage separation, PMO would use hydrazine thrusters to set itself spinning at 15 revolutions per minute (RPM) for stabilization. The antenna mast bearing the high-gain, low-gain, and two penetrator data reception antennas  would revolve in the opposite direction at the same rate, so would appear to stand still. Controllers on Earth would use the thrusters to carefully target PMO so that it would not accidentally hit Mars and introduce terrestrial microbes. They would perform a final course correction 30 days before Mars arrival.

One day out from Mars, on 6 September 1980, PMO would orient itself for its Mars orbit insertion burn and increase its spin rate to 30 RPM. The spacecraft's high-gain antenna would not point at Earth during the insertion burn. Controllers on Earth could, however, send PMO commands through the low-gain antenna.

Candidate PMO orbits. Image credit: Hughes Aircraft Company.

PMO would reach Mars late in northern hemisphere summer, when the planet's south polar cap would be near its maximum extent. Hughes Aircraft proposed two possible elliptical Mars orbits — south polar and north polar — each with a period of 24.6 hours (one martian day) and a periapsis (low point) of 1000 kilometers. South polar orbit periapsis would occur above a point on Mars's surface 72° south of the equator, while north polar orbit periapsis would occur above a point at 37° north latitude. The spacecraft's high periapsis altitude would serve to forestall orbital decay, helping to ensure that PMO would not drop living terrestrial microbes on Mars. PMO would have a mass of 741 kilograms after orbit insertion.

The PMO mission's Mars orbit phase would last one martian year (686 terrestrial days). During this mission phase, PMO would deploy its six 45-kilogram penetrators singly and in pairs using a penetrator deployment system based on the Hughes-built TOW missile launcher. Before Earth departure the penetrators would be sealed inside their launch tubes and heated to kill hitchhiking microbes.

PMO deploys its first penetrator. The departing penetrator is at center right, while the exhaust plume from its small solid-propellant rocket motor gushes from the bottom end of the penetrator launch tube at lower left. On the bottom (left) side of the spacecraft, the Mars orbit-insertion engine bell is visible, as are the bottom ends of the six penetrator tubes. One tube is partly obscured by the exhaust plume, one by the orbit-insertion engine bell, and another by a neighboring penetrator tube. The top ends of three tubes are visible; one obscures the base of the counter-spun antenna mast mounted at the center of PMO's top (right) side. The high-gain dish antenna (center), two penetrator antennas, and the low-gain antenna are attached to the mast. Image credit: Hughes Aircraft Company/DSFPortree.

Penetrator deployment would occur near apoapsis (orbit high point), when the spacecraft's orbital velocity would be at its slowest. Hinged covers would open at both ends of the launch tube, then the penetrator's solid-propellant deployment rocket motor would ignite to launch it from the tube. Launching the penetrator in the direction opposite PMO's orbital motion would cancel out its orbital velocity and cause it to fall toward Mars. The dome-nosed penetrator, a Sandia Corporation design, would drop through the martian atmosphere and implant itself in the surface up to 15 meters deep.

After impact, the penetrator would extend its antenna and begin transmitting data from its science instruments. PMO would record the penetrator data for relay to Earth through its high-gain dish. Chemical batteries in the penetrators would enable each to collect and transmit data from Mars for about eight days.

For their weak signals to be received, the penetrators would need to impact the surface not far from PMO's periapsis point. The orbiter could maintain radio contact with a given penetrator for at least eight minutes at a time. A PMO in south polar orbit would initially place its penetrators between 63° and 87° south; a north-polar-orbiting PMO would place them between 56° and 80° north. Periapsis would gradually shift north or south, however, permitting placement at other latitudes. With all six penetrators deployed, PMO would have a mass of 412 kilograms.

Viking 1 and Viking 2, each of which comprised a three-legged lander and an orbiter bearing cameras, were designed with certain assumptions in mind; for example, that microbial life on Mars would be ubiquitous, so that a scoop of surface dust and a jury of three biological experiments would readily reveal its presence. Unfortunately for the proposed 1979 PMO mission and NASA Mars exploration planning in general, the Viking biology experiments yielded equivocal results that were generally interpreted as indicative of a lifeless world. This, combined with the loss of the Mars Observer spacecraft as it attempted capture into Mars orbit in 1993, helped to create a two-decade gap during which no new U.S. spacecraft explored Mars.

Sources

Pioneer Mars Surface Penetrator Mission: Mission Analysis and Orbiter Design, Hughes Aircraft Company, August 1974.

Pioneer Mars 1979 Mission Options, A. Friedlander, W. Hartmann, and J. Niehoff, Science Applications, Inc., 29 January 1974, pp. 61-99.

Solar System Log, Andrew Wilson, Jane's, 1986, pp. 12-13, 16-17, 21.

More Information

The Russians are Roving! The Russians are Roving! A 1970 JPL Plan for a 1979 Mars Rover 

Prelude to Mars Sample Return: the Mars 1984 Mission (1977)