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

Safeguarding the Earth from Martians: The Antaeus Report (1978-1981)

The Viking 2 landing site in Utopia Planitia, a northern plain where water frost is seen on winter mornings. The lander touched down on 3 September 1976. A three-meter arm with a scoop on the end dug into the martian surface near the lander, collecting dirt to feed into its three biology experiments. The arm was also used to push rocks and dig trenches that enabled scientists on Earth to study the top 20 centimeters or so of the martian surface. Had the arm been able to dig down deeper — perhaps as little as 30 centimeters deeper — it would have encountered water ice and the history of Mars exploration could have been very different. Image credit: NASA.

In the summer of 1978, 16 university professors from around the United States gathered at NASA's Ames Research Center near San Francisco to spend 10 weeks designing an Earth-orbiting Mars sample quarantine facility. It was one of a series of similar Ames-hosted Summer Faculty Design Studies conducted since the 1960s.

At the time, NASA actively considered Mars Sample Return (MSR) as a post-Viking mission. Agency interest flagged as it became clear that no such mission would receive funding, so publication of the 1978 design study, titled Orbiting Quarantine Facility: The Antaeus Report, was delayed until 1981.

The Summer Fellows noted that the three biology experiments on the Viking landers had found neither organic carbon nor clear evidence of ongoing metabolic processes in the soil they tested on Mars. Furthermore, the Viking cameras had observed no obvious signs of life at the two rather dull Viking landing sites.

Nevertheless, the Summer Fellows argued, "the limitations of automated analysis" and the fact that "the landers sampled visually only a small fraction of one percent of the planet's surface" meant that there could be "no real certainty" about whether Mars was lifeless. This, they argued, meant that, "in the event that samples of Martian soil are returned to Earth for study, special precautions ought to be taken. . .the samples should be considered to be potentially hazardous to terrestrial organisms until it has been conclusively shown that they are not."

Their report listed three options for attempting to ensure that samples would not accidentally release martian organisms on Earth. The MSR spacecraft might sterilize the sample en route from Mars to Earth, perhaps by heating it. Alternately, the unsterilized sample might be quarantined in a "maximum containment" facility on Earth or in Earth orbit, outside our planet's biosphere.

The Summer Fellows noted that each of these three options would have advantages and disadvantages; sterilizing the sample, for example, might ensure that no martian organisms could reach Earth, but would likely also damage the sample, diminishing its scientific utility. The scientists explained that the Antaeus study emphasized the third option because it had not been studied in detail previously.

The Summer Fellows explained the significance of the name they had selected for their Orbiting Quarantine Facility (OQF) project. Antaeus was a giant in Greek mythology who forced passing travelers to wrestle with him and killed them when he won. The Earth was the source of Antaeus's power, so the hero Hercules was able to defeat the murderous giant by holding him above the ground. "Like Antaeus," they explained, a martian organism "might thrive on contact with the terrestrial biosphere. By keeping the pathogen contained and distant, the proposed [OQF] would safeguard the Earth from possible contamination."

Five 4.1-meter-diameter cylindrical modules based on European Space Agency Spacelab module hardware would form the Antaeus OQF. The Summer Fellows assumed that the modules and many of the other components needed to assemble and operate the OQF would become available during the 1980s as the Space Shuttle Program evolved into a Space Station Program.

OQF assembly in 296-kilometer-high circular Earth orbit would need two years. It would begin with the launch of drum-shaped Docking and Logistics Modules together in a Space Shuttle Orbiter's payload bay.

The 2.3-ton Docking Module, the OQF's core, would measure 4.3 meters long. It would include six 1.3-meter-diameter ports with docking units derived from the U.S. version of the 1975 Apollo-Soyuz "neuter" design. Outward-splayed guide "petals" and a system of shock absorbers and latches would enable identical docking units to link together.

The Antaeus Orbital Quarantine Facility. Image credit: NASA.

In addition to the Logistics Module, Power, Habitation, and Laboratory Modules would link up with Docking Module ports. When completed, they would form what the Fellows called a "pinwheel" design. The remaining two Docking Module ports would enable Shuttle dockings, spacewalks outside the OQF with the Docking Module serving as an airlock, and attachment of additional modules if necessary.

The 4.3-meter-long Logistics Module would weigh 4.5 tons loaded with a one-month supply of air, water, food, and other supplies. After a crew took up residence on board the OQF, a Shuttle Orbiter would arrive each month with a fresh Logistics Module. Using twin robot arms mounted in the Orbiter payload bay, the Shuttle crew would remove the spent Logistics Module for return to Earth and berth the fresh one in its place.

The second OQF assembly flight would see the Shuttle crew link the 13.6-ton Power Module to the Docking Module's aft port. The Power Module would then deploy two steerable solar arrays capable of generating between 25 and 35 kilowatts of electricity. Spinning momentum wheels would provide OQF attitude control and small thrusters would fire periodically to counter atmospheric drag, which would otherwise over time cause the quarantine station to reenter. The Power Module would also provide OQF thermal control and communications.

The OQF's five-person crew would live in the 12.4-meter-long, 13.6-ton Habitation Module, which would arrive on the third assembly flight. The OQF's "command console," five crew sleep compartments, and workshop, sickbay, galley, exercise, and waste management/hygiene compartments would be arranged on either side of a central aisle. The Hab Module would provide life support for all the OQF's modules except the Laboratory Module.

The Lab Module, delivered during the fourth and final OQF assembly flight, would measure 6.9 meters long and, like the Hab and Power Modules, would weigh 13.6 tons. Not surprisingly, the Ames Faculty Fellows devoted an entire chapter of the Antaeus report to the Lab.

Spacelab pressurized modules included a central corridor running their entire length. Experiment equipment lined their walls. The Spacelab-based OQF Lab Module, on the other hand, would have a central experiment area running most of its length with corridors along its walls. Most of the experiment area would be located within glass-walled "high-hazard" "Class III" biological containment cabinets similar to those at the Centers for Disease Control in Atlanta, Georgia.

The Antaeus OQF Lab Module included an independent life support system to help prevent contamination of adjoining modules. Grills in the floor and ceiling lead to air filters. The Mars Sample Return sample canister would enter the central experiment area from above. Visible are at least three microscopes. Image credit: NASA.

Analysis equipment within the cabinets would include a refrigerator, a freezer, a centrifuge, an autoclave, a gas chromatograph, a mass spectrometer, incubation and metabolic chambers, scanning electron and compound light microscopes, and challenge culture plates. The crew would operate the equipment from outside the cabinets using sleeve-like arms with mechanical grippers.

The Summer Fellows provided no obvious aids for crew positioning. In the illustration of the Lab module above, scientists are shown floating without hand-grips or feet or body restraints. Given the delicate and sensitive nature of the work they were meant to perform, this would probably turn out to be a significant omission.

The Lab Module would include an independent life support system with "high efficiency particle accumulator" (HEPA) filters. Experimenters would enter and exit the Lab Module through a decontamination area, where they would don and doff respirator masks and protective clothing. If a mishap contaminated the Lab Module, the module could be detached from the OQF and boosted to a long-lived 8000-kilometer circular orbit using a Laboratory Abort Propulsion Kit delivered by a Shuttle Orbiter.

Following the two-year assembly period, a rehearsal crew would board the OQF to test its systems and try out the Mars sample analysis protocol using biological samples from Earth. The Summer Fellows set aside up to two years for these practice activities. At about the time the rehearsal crew boarded the OQF, a robotic MSR spacecraft would depart Earth on a one-year journey to Mars.

Two years later and four years after the start of OQF assembly, a small Mars Sample Return Vehicle (MSRV) containing one kilogram of martian surface material and atmosphere samples would fire rocket motors to enable Earth's gravity to capture it into a high orbit. The sample would ride within a sample canister, the exterior of which would have been sterilized during Mars-Earth transfer.

Meanwhile, a Shuttle Orbiter would deliver to the OQF the first five-person sample-analysis crew. It would comprise a commander (a career astronaut with engineering training) and four scientists with clinical research experience (a medical doctor, a geobiologist, a biochemist, and a biologist).

A Shuttle-launched remote-controlled Space Tug would collect the sample canister from high-Earth orbit and deliver it to a special "docking cone" on top of the Lab Module. This is not shown in the illustration of the completed OQF; in its place, one finds a cylindrical "Sample Acquisition Port." The canister would then enter the experiment area through a small airlock.

The first sample analysis crew would cut open the canister using "a mechanism similar to a can opener." They would immediately place 900 grams of the sample into "pristine storage." Over the next 60 days, they would execute an analysis protocol that would expend 100 grams of the sample. Twelve grams each would be devoted to microbiological culturing and challenge cultures containing living cells from more than 100 Earth species; six grams each to metabolic tests and microscopic inspection for living cells and fossils; 10 grams to chemical analysis; and 54 grams to "second-order" follow-up tests.

If the 60-day analysis protocol yielded no signs of life in the test sample, a Shuttle Orbiter would carry the 900-gram pristine sample from the OQF to Earth's surface for distribution to laboratories around the world. Based on highly optimistic 1970s NASA estimates of Shuttle, Spacelab, and Station costs, the Summer Fellows placed the total cost of OQF assembly and operations for this "minimum scenario" at only $1.66 billion.

If, on the other hand, OQF scientists detected life in the Mars sample, then analysis on board the OQF could be extended for up to six and a half years. Throughout that period, Shuttle Orbiters would continue to deliver a steady stream of monthly Logistics Modules; they would also change out OQF crews at unspecified intervals. In all, about 80 Logistics Modules would reach the OQF by the time its mission ended. The cost of this "maximum scenario" might total $2.2 billion, the Ames Summer Faculty Fellows optimistically estimated.

Source

Orbiting Quarantine Facility: The Antaeus Report, D. DeVincenzi and J. Bagby, editors, NASA, 1981.

More Information

Clyde Tombaugh's Vision of Mars (1959)

Peeling Away the Layers of Mars (1966)

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

NASA Johnson's Plan to PEP Up Shuttle/Spacelab (1981)

Early artist concept of a Space Shuttle Orbiter with a "Sortie Lab" at the front of its Payload Bay. The Sortie Lab pressurized module is shown as a cutaway illustration. At this point in its history, the Sortie Lab was expected to be manufactured by a U.S. aerospace contractor. The Sortie Lab depicted is dedicated at least partly to astronomy, as evidenced by the large telescope attached to the aft end of its pressurized module. Image credit: NASA.

On 29 November 1972, NASA Administrator James Fletcher abolished the Space Station Task Force formed in early 1969 by his predecessor, Thomas Paine, and formed the Sortie Lab Task Force. The "Sortie Lab," a concept that emerged during Phase B Space Station planning in 1970, was envisioned as a pressurized laboratory module which would be carried in the Shuttle Orbiter's Payload Bay.

Fletcher's move acknowledged that the Space Shuttle, conceived originally as a vehicle for transporting crews and cargoes between Earth and an Earth-orbiting Space Station at low cost, would need to become a Space Station — or, at least, an interim space laboratory that could demonstrate that a Space Station would be a desirable new NASA goal after the Space Shuttle became operational.

Strapped for funds and encouraged by President Richard Nixon to use spaceflight as a vehicle for international cooperation, NASA asked the European Space Research Organization (ESRO), a predecessor of the European Space Agency (ESA), to provide the Sortie Lab in exchange for European astronaut flights on board the Shuttle. In August 1973, ESRO and European aerospace contractors agreed to build the Sortie Lab, which became known as Spacelab.

Cutaway illustration of a drum-shaped, ESA-built Spacelab module (center) with a pair of U-shaped Spacelab pallets (left). A bent tunnel with an airlock on top for spacewalks (note space-suited astronaut atop pallet at left) links Spacelab with the Shuttle Orbiter Mid-Deck, the main living space for the crew. Above that is the Flight Deck, the Orbiter cockpit. Image credit: NASA.

Spacelab would provide scientists with ample pressurized volume in which to conduct research, but it would rely on limited resources — for example, electricity — provided by the Shuttle Orbiter. Orbiter electricity came from a trio of liquid oxygen/liquid hydrogen fuel cells that in early 1981 were expected to generate 21 kilowatts continuously for just seven days. Of this, 14 kilowatts were required for Orbiter systems. The Orbiter could thus supply only seven kilowatts to Spacelab. Of those seven kilowatts, between two and five kilowatts would be needed for basic Spacelab systems, leaving a paltry two to five kilowatts for Spacelab experiments.

In 1978, NASA Johnson Space Center (JSC) in Houston, Texas, launched the Orbital Service Module Systems Analysis Study, which looked into ways that the Space Shuttle Orbiter could be augmented to enable it to better support Spacelab research. An early product of the study was the Power Extension Package (PEP) concept.

Stowed PEP components in the Space Shuttle Orbiter Payload Bay, between the front of a Spacelab module (right) and the rear of the Orbiter crew cabin. Image credit: NASA.

The PEP deployed in orbit. PEP displays and controls were meant to be located on the Shuttle Orbiter Flight Deck. Image credit: NASA.

The PEP concept was linked with NASA's extensive efforts in cooperation with the U.S. Department of Energy to justify the construction of enormous Earth-orbiting Solar Power Satellites (SPSs). It was portrayed as an experience-building experimental test-bed for SPS technology in the Von Karman Lecture JSC director Christopher Kraft presented to the 15th meeting of the American Institute of Aeronautics and Astronautics in July 1979. The PEP may also have been conceived as a rival for NASA Marshall Space Flight Center's Power Module (see "More Information" below).

The PEP Project Office (PEPPO) at JSC pitched the PEP in a brief report published one month before the first Space Shuttle flight (STS-1, 12-14 April 1981). The PEPPO envisioned the PEP as a "kit" that could be installed easily in the Shuttle Orbiter Payload Bay over the tunnel that would link the Orbiter Mid-Deck with the Spacelab pressurized module.

One hour after launch from Earth, an astronaut on the Orbiter Flight Deck would use the Canada-built Remote Manipulator System (RMS) robot arm to grapple the PEP's Array Deployment Assembly (ADA) and extend it out over the Orbiter's side. The ADA would then unroll a pair of lightweight solar array wings that together would measure more than 100 feet wide. PEP deployment would require about 30 minutes.

The PEP arrays would track the Sun automatically no matter how the Orbiter became oriented, so almost no astronaut intervention would be needed after they were deployed. The RMS and arrays would be sufficiently sturdy to remain deployed during Orbiter attitude-control maneuvers, but the crew would need to stow them before Orbital Maneuvering System burns lest the acceleration cause damage.

The twin arrays would generate a total of 26 kilowatts of electricity. A cable built into the RMS would carry the electricity from the ADA to the PEP's Power Regulation and Control Assembly (PRCA) in the Payload Bay. The PRCA would then distribute it to the Orbiter's electrical system.

The three Orbiter fuel cells would "idle" while the PEP arrays were in sunlight. Each would generate one kilowatt of electricity, bringing the total available on board to 29 kilowatts. Fifteen kilowatts would be available for Spacelab, of which between 10 and 13 kilowatts could be devoted to experiments.

Keeping the Spacelab electricity supply constant throughout each 90-minute orbit of the Earth would require that Orbiter fuel cell output ramp up rapidly from three to 29 kilowatts as the PEP arrays passed into darkness over Earth's night side. To achieve this output, each fuel cell would need to exceed its normal maximum by nearly three kilowatts. The fuel cells would then return to their idle state as the PEP arrays passed again into sunlight. Although it would almost certainly place unusual demands on the Orbiter fuel cells, the PEPPO judged this approach to be "feasible."

The PEPPO estimated that a PEP could extend Shuttle/Spacelab endurance in Earth orbit by four days (that is, to a total of 11 days). If other Orbiter resources (for example, life support consumables) could be augmented, then mission duration might be stretched to 45 days.

The PEPPO explained that it jointly managed PEP solar cell development with NASA's Lewis Research Center. Industry involvement in the PEP project was, it added, already "extensive," with several companies working on small NASA contracts or funding PEP-related work themselves. It estimated that the PEP could power a Spacelab module in Earth orbit as early as 1985 for a total development cost of only $150 million.

Spacelab 1 in Columbia's Payload Bay during STS-9 as viewed from the Flight Deck windows. Cables linking the Orbiter to Spacelab 1 are visible at lower right. Image credit: NASA.

The first Spacelab, appropriately designated Spacelab 1, reached orbit in the Payload Bay of the Orbiter Columbia on 28 November 1983, as part of the ninth Shuttle mission. Columbia's crew for mission STS-9 included ESA's Ulf Merbold, the first non-U.S. astronaut to reach space on board a U.S. spacecraft. Merbold was part of a six-man crew that also included Gemini, Apollo, and Shuttle veteran John Young, Skylab 3 veteran Owen Garriott, and spaceflight rookies Brewster Shaw, Robert Parker, and Byron Lichtenberg. Columbia landed at Edwards Air Force Base, California, on 8 December, ending a busy 10-day mission.

Columbia's fuel cells powered Spacelab 1, and all of the 27 Spacelab missions that followed relied on Orbiter fuel cells for their electricity. PEP work had ended in late 1981 as NASA Headquarters took charge of and terminated Shuttle augmentation and Space Station development efforts across the agency. It did this in part to clear the decks as it began formally to seek approval for a Space Station, which it billed as the "next logical step" after the Space Shuttle. President Ronald Reagan called on Congress to approve new-start funding for a Space Station during his annual State of the Union address in January 1984, less than two months after STS-9. 

Sources

Power Extension Package (PEP) Concept Summary, JSC-AT4-81-081, NASA Johnson Space Center, PEP Project Office, March 1981.

The Solar Power Satellite Concept, NASA JSC 14898, Christopher C. Kraft; Von Karman Lecture, 15th Annual Meeting of the American Institute of Astronautics and Aeronautics, July 1979.

"Spacelab joined diverse scientists and disciplines on 28 Shuttle missions," Science@NASA, 15 March 1999 (https://science.nasa.gov/science-news/science-at-nasa/1999/msad15mar99_1/ - accessed 25 March 2017).

More Information

Electricity from Space: The 1970s DOE/NASA Solar Power Satellite Studies

Evolution vs. Revolution: The 1970s Battle for NASA's Future

Lunar GAS (1987)

During the STS-91 (2-12 June 1998) mission to the Russian Mir space station, the Space Shuttle Orbiter Discovery carried four pairs of GAS canisters along its Payload Bay walls. The red arrow points to one pair. Image credit: NASA.

NASA's Get Away Special (GAS) Program (officially the Small Self-Contained Payloads Program) was conceived in 1976 as a way of providing researchers with low-cost opportunities to fly experiments in the Space Shuttle Orbiter's 15-foot-by-60-foot payload bay. The first operational GAS canister, with a suite of 10 experiments developed by students at Utah State University, Weber State University, and the University of California at Davis, reached low-Earth orbit (LEO) during mission STS-4 (27 June-4 July 1982) on board the Orbiter Columbia. By 17 March 2005, when NASA terminated the GAS Program in the aftermath of the 1 February 2003 Columbia disaster, nearly 170 GAS canisters had flown in low-Earth orbit (LEO).

If four engineers at the Jet Propulsion Laboratory (JPL) in Pasadena, California, had had their way, a GAS payload might have traveled far beyond LEO. In May 1987, the team proposed that an advanced-design small spacecraft be launched on board a Space Shuttle inside an Extended GAS canister and ejected into Earth orbit. The spacecraft, called Lunar GAS (LGAS), would then use electric-propulsion thrusters to spiral outward to the moon.

Close-up of two of the STS-91 GAS canisters in Discovery's Payload Bay. Image credit: NASA.

LGAS anticipated the small, relatively cheap spacecraft of NASA's 1990s Discovery Program, the first mission of which, Near Earth Asteroid Rendezvous (NEAR), departed Earth in 1995. The Discovery Program, a significant break from the large-spacecraft paradigm that characterized much U.S. planetary mission development in the 1970s and 1980s, got its start in 1991-1992 as Defense Department space technology developed for President Ronald Reagan's Strategic Defense Initiative "missile shield" trickled into the civilian space sector. The Discovery Program would become an intermediate evolutionary step leading toward the present-day Cubesat revolution.

The LGAS mission would begin up to three months before planned Space Shuttle launch with the insertion of the 149-kilogram spacecraft into its Extended GAS canister. The spacecraft would at that point enter the routine GAS payload processing flow and no one would see it again until it left its canister in LEO.

The Shuttle Orbiter bearing the LGAS spacecraft would lift off from Kennedy Space Center in Florida and enter an orbit inclined 28.5° relative to Earth's equator. The astronauts would then open its payload bay doors, exposing the closed Extended GAS canister bearing LGAS to space.

NASA required that GAS experiments place minimal demands on Shuttle expendables and astronaut time. The JPL team insisted that, despite its complexity, the LGAS mission could meet this requirement. A few hours after launch, one astronaut would flip a single switch on the Shuttle flight deck to open the motorized Extended GAS canister lid, then would flip two more to release a latch and activate a spring ejection mechanism.

Simplified schematic of the LGAS spacecraft following deployment from its GAS canister. Image credit: JPL/NASA.

The barrel-shaped LGAS spacecraft would leave the Extended GAS canister moving at one meter per second; then, as it moved away from the Shuttle Orbiter, it would automatically extend its twin accordion-fold solar-array wings and its science boom. The slender advanced-design rectangular solar arrays would each have a mass of about 15 kilograms. Their combined 7.25 square meters of collecting area would generate 1.467 kilowatts of electricity at mission start.

Two small chemical-propellant thrusters would turn the spacecraft to point its solar arrays and spin axis toward the Sun, then would spin its barrel-shaped body end over end at up to five revolutions per minute to create gyroscopic stability. After it had moved a safe distance away from the Shuttle, the LGAS spacecraft would switch on one of its twin electric thrusters. Mounted on opposite sides of the spacecraft body, these would take turns thrusting parallel to its spin axis. Fueled from a round tank containing 36 kilograms of compressed xenon gas, the thrusters would each be designed to withstand 3500 start/stop cycles and to operate for a total of 4500 hours (187.5 days).

LGAS spacecraft electric-propulsion thrust and coast arcs during escape from Earth orbit. Image: JPL/NASA.

The LGAS spacecraft's orbit about the Earth would for mission operations purposes be divided into four 90° arcs, the JPL engineers explained. In the first arc, one thruster would point opposite the LGAS spacecraft's direction of motion so that when it operated it would accelerate the spacecraft. In the second arc, which would occur in Earth's shadow, both thrusters would point perpendicular to the spacecraft's direction of motion; this would mean that they could not contribute to accelerating the spacecraft, so they would not operate.

In the third arc, the second thruster would point opposite the LGAS spacecraft's direction of motion, so it would switch on to take its turn accelerating the spacecraft. In the fourth arc, which would see the spacecraft pass between the Earth and the Sun, the thrusters would again point perpendicular to its direction of motion, so would not operate.

Overcoming drag from Earth's atmosphere would require about one-third of the LGAS spacecraft's thrust early in the departure spiral, the team calculated, but drag would taper off quickly as the spacecraft raised its orbital altitude by up to 20 kilometers per day. Starting about three months after launch from the Shuttle, the LGAS spacecraft would spend between 100 and 150 days inside the Earth-girdling Van Allen Belts. High-energy particles in the Belts would gradually degrade the twin wing arrays, reducing their electricity output.

Image credit: JPL/NASA.

About 600 days after launch, the LGAS spacecraft would reach a point about 130,000 kilometers away from the Earth. It would then turn off its thrusters and coast in a lazy 15-day "linking orbit" that would deposit it into a loosely bound 40,000-kilometer circular lunar polar orbit.

The xenon-fueled thrusters would then resume alternating operation with their 90° thrust arcs centered over the moon's polar regions; this time, however, the thrusters would point in the spacecraft’s direction of motion when they operated, gradually slowing the LGAS spacecraft so that it would spiral in toward the moon.

The spacecraft would achieve a 100-kilometer-high, two-hour lunar polar orbit about two years after it departed its Extended GAS canister. In its orbit over the moon's poles, the moon would rotate beneath it about once per month, enabling it to eventually overfly the entire lunar surface. Irregularities in the moon's gravity field would mean that the electric thrusters would need to adjust the spacecraft's orbit about every 60 days.

The LGAS spacecraft would have room for only one science instrument: a 15-kilogram gamma-ray spectrometer (GRS) for charting the composition of the moon's crust. The JPL engineers proposed that the unflown Apollo 18 GRS be mounted on the LGAS science boom. Lunar-orbital science operations would continue for about one year.

Sources

"Lunar Get Away Special (GAS) Spacecraft," AIAA-87-1051, K. T. Nock, G. Aston, R. P. Salazar, and P. M. Stella; paper presented at the 19th AIAA/DGLR/JSASS International Electric Propulsion Conference in Colorado Springs, Colorado, 11-13 May 1987.

"Getaway Special," Wikipedia (https://en.wikipedia.org/wiki/Getaway_Special — accessed 18 March 2017).

More Information

On the Moons of Mighty Jupiter (1970)

Cometary Explorer (1973)

Catching Some Comet Dust: Giotto II (1985)

NASA Johnson Space Center's Shuttle II (1988)

Image credit: NASA.

Although the fact is mostly forgotten today, NASA launched plans to augment or replace the Space Shuttle even before the first Shuttle reached orbit on 12 April 1981. Much — though by no means all — of this planning occurred as part of joint Department of Energy/NASA Solar Power Satellite studies.

In 1985, U.S. President Ronald Reagan signed a directive ordering the U.S. civilian space agency to develop a Space Shuttle successor. Notably, this occurred before the 28 January 1986 Challenger accident laid bare the Shuttle system's many frailties.

One proposed Shuttle successor was called Shuttle II. Most Shuttle II design work took place at NASA Langley Research Center (LaRC) in Hampton, Virginia. Shuttle II first achieved prominence in 1986 in the high-level National Commission On Space report Pioneering the Space Frontier.

LaRC's Shuttle II design evolved — for a time it was to have been a single-stage-to-orbit vehicle. The favored design included a winged manned Orbiter and a winged unmanned Booster, both of which would take off vertically and land horizontally on runways. Both the Booster and the Orbiter would be entirely reusable. LaRC's Shuttle II Orbiter fuselage was meant to be crammed full of propellant tanks, so would tote cargo in a sizable hump on its back.

NASA Langley Research Center's dumpy Shuttle II, 1987. Image credit: NASA.

Shuttle II was intended mainly as a crew transport complementing a "mixed fleet" of launchers that would have included unmanned heavy-lift rockets capable of placing from 50 to 100 tons into space. LaRC envisioned that its Shuttle II would transport a small amount of cargo — perhaps 10 tons — and up to 25 astronauts, of whom only three would be considered Shuttle II crew members. The remainder would be passengers bound for a large advanced Space Station or a Transportation Node station. There they would board Moon or Mars spacecraft.

Although a good case can be made for calling LaRC's Shuttle II the Shuttle II, it was in fact not the only proposed Shuttle II design. The Advanced Programs Office at NASA Johnson Space Center (JSC) in Houston, Texas, put forward the sleek Shuttle II design depicted in the last seven images of this post. They portray JSC's Shuttle II as it would appear over the course of a typical mission.

The LaRC design was favored by NASA Headquarters and is relatively well documented. Neither can be said for JSC's design.

In flight: the Evolved Shuttle climbs toward space, probably sometime in the 1990s. Image credit: Eagle Engineering/NASA.

Model of proposed Evolved Shuttle showing major components. Image credit: NASA.

Engineers in Houston envisioned that their Shuttle II might develop from an Evolved Space Shuttle. In the Evolved Shuttle, Liquid Replacement Boosters stood in for the Shuttle's twin Solid Rocket Boosters. The Evolved Shuttle would retain the Shuttle's expendable External Tank and, with minor modifications, the Shuttle Orbiter's Space Shuttle Main Engines (SSMEs). Like the Space Shuttle, the Evolved Shuttle stack would ride to its Launch Complex 39 pad atop a creeping crawler-transporter with its nose aimed at the sky.

Winglets on the tips of the Evolved Shuttle's modified delta wings would replace the Shuttle's single vertical tail fin. Redesigned Orbital Maneuvering System (OMS) engines based on the venerable RL-10 engine would draw liquid hydrogen/liquid oxygen propellants from insulated tanks built into the Evolved Shuttle Orbiter wings.

The most dramatic changes would, however, be reserved for the Evolved Shuttle crew compartment. JSC engineers designed it so that it could separate from the Evolved Shuttle in the event of catastrophic failure and operate as an independent spacecraft. Canard winglets meant to improve the Evolved Shuttle's aerodynamic characteristics would separate with the crew compartment and become its wings.

JSC gave no timeline for the evolution of Shuttle to Evolved Shuttle. If, however, JSC's Shuttle II was to become operational in the same timeframe as LaRC's Shuttle II (the early 21st century), then one may assume that the Evolved Shuttle would have made its debut in the 1990s.

Shuttle II ready for a tow to its launch pad. A round panel covering an extendable docking adapter is visible just above the American flag on the fuselage. Image credit: NASA.

The JSC Shuttle II was meant to be towed horizontally on its tricycle landing gear from a hangar to its launch pad just four hours before planned launch. Unlike the Space Shuttle and Evolved Shuttle, JSC's Shuttle II would have no need of the Vehicle Assembly Building, the massive cuboid structure built at Kennedy Space Center in the 1960s for the assembly of Apollo Saturn V heavy-lift rockets.

Nor would it use the twin Launch Complex 39 pads, which were built in the 1960s to launch Saturn V rockets and rebuilt in the 1970s to launch the Space Shuttle. Shuttle II would instead lift off from a new-design pad, and Complex 39 would be given over once again to heavy-lift rocket launches. In fact, the JSC Shuttle II would make a complete break from the massive-scale Apollo-era infrastructure upon which the Space Shuttle relied.

JSC's Shuttle II in launch configuration. The round panel covering the extendible docking adapter is again visible; it leads to a crew access tunnel that runs the length of the spacecraft. Image credit: NASA.

At the launch pad, crew and passengers would board JSC's Shuttle II, then it would be tipped up to point its nose at the sky. Its landing gear doors would be closed, then its ground crew — small compared with the army of personnel that serviced the Space Shuttle — would load it with three kinds of propellants: liquid hydrogen fuel, liquid hydrocarbon (kerosene or propane) fuel, and liquid oxygen oxidizer.

For safety, most of the volatile fuels would be pumped into Shuttle II's four expendable over-wing tanks, while an integral, reusable tank within the spacecraft would carry most of the dense liquid oxygen. Fully loaded with propellants and payload, Shuttle II would weigh about 550 tons, or a little more than a quarter of the Shuttle's weight at SSME ignition.

JSC designers hoped to minimize Shuttle II weight in part by building it from advanced materials. The Space Shuttle Orbiter, with an empty mass of about 85 tons, had a more-or-less conventional load-bearing aluminum-titanium airframe clad in aluminum and lightweight thermal-protection materials. These included thousands of uniquely shaped ceramic tiles and Reinforced Carbon-Carbon (RCC) wing leading edges. Shuttle II, with an empty mass of 50 to 75 tons, would also rely on RCC, "but in larger, load-bearing, monolithic panels." The over-wing tanks would be made from lightweight welded aluminum-lithium alloy.

At launch, Shuttle II's single Space Transportation Main Engine (STME) and twin Space Transportation Boost Engines (STBEs) would ignite simultaneously. The former, designed to burn liquid hydrogen and liquid oxygen, was envisioned as a second-generation SSME. The latter, located between the STME and the Shuttle II body flap, would burn hydrocarbon fuel and liquid oxygen and employ liquid hydrogen as engine coolant. The STME and STBEs would together generate about 30% more thrust than the Space Shuttle's three SSMEs — between 1.3 and 1.6 million pounds.

Climb to orbit: JSC's Shuttle II following detachment of its outboard tanks and its twin STBEs. Image credit: NASA.

When it reached a velocity of between two and three kilometers per second, JSC's Shuttle II would shed its depleted outboard over-wing tanks and the STBEs. Dropping the STBEs would improve Shuttle II's flight performance by shifting its center of gravity forward. The tanks would break up and fall into the sea, but NASA would recover the twin engines for reuse. JSC engineers envisioned that they would descend in reentry shells, deploy maneuvering parachutes, and land in arresting nets aboard recovery ships.

The STME, meanwhile, would extend its telescoping exhaust nozzle to its full length and diameter to improve its performance in vacuum. Following separation of the outboard tanks and STBEs, the spacecraft would burn only liquid hydrogen/liquid oxygen propellants.

Immediately following STME cutoff, the engine's nozzle would retract and the inboard over-wing tanks would be cast off. Upon reaching apogee (the highest point in its orbit about the Earth), Shuttle II's twin OMS engines would ignite to raise its perigee (the lowest point in its orbit) out of the atmosphere. This would place it into a circular "Space Station rendezvous orbit" 485 kilometers high and inclined 28.5° relative to Earth's equator. The inboard tanks, meanwhile, would intersect Earth's atmosphere as they reached perigee and be destroyed.

The Shuttle II OMS would comprise a pair of new-design Advanced Space Engines or RL-10-derived engines. RL-10 had the advantage of a long flight history; derivatives of that engine have propelled upper stages and spacecraft since the 1960s. Liquid hydrogen and liquid oxygen for Shuttle II's OMS and the Reaction Control System (RCS) thrusters would be stored in double-walled, heavily insulated tanks in its tail section. Some propellants from the tail section would be combined in next-generation fuel cells to generate electricity and water for the spacecraft.

A crew access tunnel would run aft from the forward crew compartment for most of the length of the fuselage. Midway along the tunnel, on its left side, Shuttle II's docking adapter for linking up with the Space Station would be stowed behind a streamlined panel. The round panel is visible near the American flag in images that display the left side of the Shuttle II model. Prior to rendezvous with the Space Station, the panel would hinge out of the way, then the crew would extend the cylindrical docking adapter.

The image above shows Shuttle II in its orbital configuration with inboard tanks in place; this is apparently a photographer's error, since image captions make plain that the inboard tanks would separate immediately after STME cutoff, before the crew opened the payload bay. Image credit: NASA.

JSC engineers chose a novel method for exposing Shuttle II payloads to space: the crew would disable the OMS engines, vent and disconnect hoses that had linked the over-wing tanks to the STME, disengage locks, and hinge the tail section downward using electric motors. RCS thrusters in the tail would continue to operate; to minimize flexible wiring links between the main fuselage and the tail section, engineers proposed that the astronauts control the RCS thrusters via a short-range radio link.

Hinging the tail section down would expose a large round window and the open aft end of the 15-foot-wide-by-30-foot-long cylindrical payload bay. Astronauts at an aft workstation would look out through the window as they extended the cradle bearing their mission's payload. The photo captions do not name specific Shuttle II payloads, but it is logical to assume that these would include experiment packages for mounting on the Space Station and reusable Station logistics modules packed full of supplies and equipment. The payload bay would include an airlock for spacewalks and a pair of robot arms.

Unlike the Space Shuttle and Evolved Shuttle payload bays, the Shuttle II bay would normally not include radiators for dissipating heat generated by onboard equipment and astronaut exertions. Instead, Shuttle II's radiators would be built into the top surface of its wings. Supplemental radiators would be mounted on the payload cradle before flight only if "special purpose, high heat load conditions" were expected.

Before return to Earth, the astronauts would retract the payload cradle, then hinge shut the tail section. Shuttle II would include triple-redundant electric motors and a mechanical backup system for closing the payload bay "to assure that the vehicle configuration for entry [would] not have paths for hot plasma to enter the vehicle interior." During the first few Shuttle II flights, an astronaut would exit through the docking adapter and clamber over the fuselage to inspect the hinge area and seam between the tail section and the rest of the spacecraft. He or she might carry a repair kit "to fill any voids."

Reentry would occur as in the Space Shuttle Program; that is, Shuttle II would turn so that its aft end pointed in its direction of flight, then its OMS engines would ignite to reduce its orbital velocity. The spacecraft would then flip to point its nose forward as it fell toward the atmosphere. Following reentry, Shuttle II would glide to a runway landing.

JSC's Shuttle II in landing configuration. Image credit: NASA.

Unlike the Space Shuttle, which even after the Challenger accident included few realistic options for crew escape in the event of catastrophic failure, Shuttle II could in theory protect its crew through all phases of its mission. Like the Evolved Shuttle, Shuttle II would include a separable crew compartment; after separation, Shuttle II's canard fins — proportionately larger than those of the Evolved Shuttle — would become the crew compartment's wings.

The crew compartment aft end would include launch escape/deorbit rocket engines, a crew hatch, and a deployable aerodynamic flap. Following separation in orbit, the crew compartment could support 11 astronauts for up to 24 hours. This endurance was meant to ensure that Earth's rotation could bring into range a suitable landing site on U.S. soil. The crew compartment would touch down and slide to a halt on extendable skids.

Crew cabin separation on the launch pad or during ascent. Image credit: NASA.

Crew cabin separation in orbit or during reentry. Image credit: NASA.

JSC engineers acknowledged that wind-tunnel testing might show that the Shuttle II crew compartment shape was not flight-worthy in all abort situations. They proposed that inflatable or extendable structures "be employed to obtain an acceptable configuration for hypersonic, supersonic, and subsonic controlled flight."

They also proposed that the Shuttle II crew compartment become the Space Station's Crew Emergency Rescue Vehicle (CERV). The CERV was conceived as a "lifeboat" for use if the Space Station had to be evacuated rapidly, if a crew member became seriously ill or injured and needed hospital treatment on Earth, or if Shuttle II became grounded due to malfunction or accident and could not retrieve a Space Station crew.

The JSC engineers noted that the Shuttle II crew compartment/CERV, like Shuttle II itself, would subject its occupants to no more than three gravities of acceleration or deceleration. This would help to ensure that, during return to Earth, it would not inflict additional harm on a sick or injured Space Station crewmember.

NASA continued to attempt to develop a Shuttle successor — a winged spacecraft that would enable it to apply the lessons learned from the Shuttle Program. Some proposed complex new vehicles employing scramjets; others, vehicles smaller and less capable than the Shuttle tailored mainly for Space Station crew rotation and crew escape. Unfortunately, the space agency's budget was not expanded to permit simultaneous ongoing Shuttle operations, Space Station development and assembly, and development of a Shuttle successor.

By the mid-1990s, many in the Shuttle Program had changed their tactics; they declared that the Shuttle should continue to fly at least until 2010. In 2001, Boeing proposed that the Shuttle should fly until 2030.

The 2003 Columbia accident ended such plans. When the Shuttle was retired in 2011, a new NASA Shuttle design was as far away as it had been during Shuttle II planning in the late 1980s.

Sources

Caption Sheet, NASA Photo S88 29029, Shuttle II Candidate Configuration, 1988.

Caption Sheet, NASA Photo S88 29035, Shuttle II Launch Configuration, 1988.

Caption Sheet, NASA Photo S88 29032, Shuttle II Post-Boost Flight Configuration, 1988.

Caption Sheet, NASA Photo S88 29028, Shuttle II Orbital Flight Configuration, 1988.

Caption Sheet, NASA Photo S88 29026, Shuttle II Entry and Landing Configuration, 1988.

Caption Sheet, NASA Photo S88 29024, Shuttle II Pad Abort Crew Escape, 1988.

Caption Sheet, NASA Photo S88 29030, Shuttle II Crew Escape System, 1988.

Caption Sheet, NASA Photo S89 34837, Evolved Shuttle, 1989.

"Shuttle II Progress Report," T. Talay, NASA Langley Research Center; paper presented at the 24th Space Congress, 21-24 April 1987, Cocoa Beach, Florida.

Pioneering the Space Frontier: the Report of the National Commission on Space, Bantam Books, 1986.

"At 15, A Safer, Cheaper Shuttle," J. Asker, Aviation Week & Space Technology, 8 April 1996, pp. 48-51.

"Boeing upgrade would keep Space Shuttle flying to 2030," G. Warwick, Flight International, 8-14 May 2001, p. 37.

More Information

Electricity from Space: The 1970s DOE/NASA Solar Power Satellite Studies

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

One Space Shuttle, Two Cargo Volumes: Martin Marietta's Aft Cargo Carrier (1982)

"A Vision of the Future": Military Uses of the Moon and Asteroids (1983)

Image credit: U. S. Department of Defense.

On the evening of 23 March 1983, U.S. President Ronald Reagan addressed the people of the United States from the Oval Office. Citing aggressive moves on the part of the Soviet Union, he defended proposed increases in U.S. military spending and the introduction of new missiles and bombers. He then called for a revolution in U.S. strategic doctrine.

"Let me share with you a vision of the future," Reagan began. He then summed up that vision in the form of a two-part question replete with the Cold War language of his Presidency: "What if free people could live secure in the knowledge that their security did not rest upon the threat of instant U.S. retaliation to deter a Soviet attack, that we could intercept and destroy strategic ballistic missiles before they reached our own soil or that of our allies?"

Reagan acknowledged that his vision represented "a formidable technical task, one that may not be accomplished before the end of this century." He then called on U.S. scientists — "those who gave us nuclear weapons" — to direct their talents "to the cause of Mankind and world peace, to give us the means of rendering these nuclear weapons impotent and obsolete."

President Ronald Reagan shares his missile-defense vision with the American people. The image on the easel is a declassified satellite view of Soviet MiG aircraft stationed in Cuba. Image credit: The Reagan Library.

Thus was born the Strategic Defense Initiative (SDI), which is perhaps better known by its cinema-inspired nickname "Star Wars." This post is not meant to discuss the origins, geopolitics, or technical feasibility of SDI. It will instead focus on one of the lesser-known aspects of SDI planning: the potential use of space resources.

The Reagan White House appointed James Fletcher, NASA Administrator from 1971 until 1977 under Presidents Nixon and Ford, to head up a panel to propose an SDI experiment and development program. Fletcher tasked the California Space Institute (Calspace) at the University of California-San Diego (UCSD) with organizing a workshop to consider whether exploitation of the resources of the Moon and asteroids might help to give substance to Reagan's vision. The Defense Applications of Near-Earth Resources Workshop took place in La Jolla, California, on 15-17 August 1983.

That Fletcher should have asked Calspace to assist with his SDI report is not too surprising. In February 1977, James Arnold, a UCSD chemistry professor, had spoken with NASA Administrator Fletcher about making the exploitation of near-Earth space resources a major new focus for NASA. He subsequently summed up his thoughts in a detailed two-page letter to Fletcher. Three years later, Arnold became the first director of Calspace, which had its origins in California Governor Jerry Brown's enthusiasm for technological development in his state.

Arnold's deputy in 1983-1984, young planetary scientist Stewart Nozette, organized the La Jolla workshop, which brought together 36 prominent scientists and engineers from aerospace companies, national laboratories, NASA centers, the Department of Defense, and defense think-tanks to weigh in on the potential use of Moon and asteroid resources in SDI. Nozette also edited the workshop report, a draft of which Arnold submitted to Fletcher on 18 August 1983. A revised final version of the workshop report was completed on 31 October 1983. This post is based upon the latter version.

In the cover letter to the La Jolla workshop report, Nozette described how, in the late 1970s, NASA, aerospace companies, and universities expended a great deal of time and effort on planning large structures — for example, Solar Power Satellites — which would be assembled in space. Some of these plans relied on space resources. Nozette explained that these studies, though conducted "in an unfocused and low priority vein," had laid the groundwork for SDI exploitation of Moon and asteroid resources. The La Jolla workshop was, he added, the first to consider the defense implications of the 1970s concepts.

Lunar prospector: Apollo 16 astronaut Charles Duke collects geologic samples in the Descartes region of the Lunar Highlands in April 1972. The Lunar Roving Vehicle is just visible among rocks and boulders in the background. Image credit: NASA.

At the time of the La Jolla workshop, relatively little was known of near-Earth space resources. Five Lunar Orbiter spacecraft had imaged much of the Moon at modest resolution and selected areas of it — mostly corresponding to potential Apollo landing sites — at higher resolution. NASA had landed Apollo astronauts at six sites between 1969 and 1972 and scientists had analyzed many of the more than 2400 geologic samples they collected. In addition, Apollo astronauts had surveyed the Moon from lunar orbit using remote sensors. These provided low-resolution data on the composition of perhaps 10% of the lunar surface.

Scientists had hypothesized since 1961 that permanently shadowed craters at the lunar poles might contain ice deposited by comet impacts. The lunar poles, far from the "Apollo Zone" — the near-equatorial region where orbital mechanics dictated the Apollo Lunar Modules could land — nevertheless remained unexplored.

In 1983, only 75 near-Earth asteroids (NEAs) had known orbital paths; the rate of discovery in the late 1970s/early 1980s suggested a population of sizable NEAs numbering many thousands, of which perhaps 20% would be readily accessible to prospecting spacecraft (these early gross estimates have been revised downward over the years). Meteorites collected on Earth were assumed (correctly) to have originated among the NEAs, but for the most part they could not yet be traced to specific asteroids.

The La Jolla workshop report thus urged more exploration as an early step toward exploitation of near-Earth resources. An automated prospecting spacecraft that would pass over both lunar poles during each orbit — a Lunar Polar Orbiter (LPO) — topped the Workshop's list of "projects to be started immediately." A spacecraft in lunar polar orbit could pass over the entire lunar surface in daylight every month.

In addition, the La Jolla workshop report recommended that efforts to discover and perform initial analyses of NEAs using Earth-based telescopes should be stepped up dramatically. It noted that, in terms of NEAs accessible to spacecraft, "the most promising targets very likely have not, as yet, been detected." The workshop report then urged NASA to carry out a series of automated NEA rendezvous missions.

In 1983, NASA's piloted spaceflight focus was on working the bugs out of the Space Shuttle, which, despite a minimal flight record (the eighth Shuttle mission flew between the La Jolla workshop and completion of the Fletcher Report), already had an extensive manifest of planned missions. Many within the space community hoped that President Reagan would soon green-light a NASA Space Station that would be launched in pieces in the payload bays of Shuttle Orbiters and assembled in low-Earth orbit (LEO). They expected that auxiliary spacecraft, including piloted Orbital Transfer Vehicles (OTVs) for reaching beyond Shuttle/Station orbit, would be based permanently at the Station.

An Orbital Transfer Vehicle (left) maneuvers in lunar orbit near a tank farm and a Moon lander. This 1983 concept art by Pat Rawlings illustrates a lunar oxygen mining infrastructure: SDI-related facilities and vehicles in lunar orbit would no doubt have appeared very similar. Image credit: NASA.

The La Jolla workshop participants saw in the OTVs the potential for carrying out piloted mining missions to the Moon and NEAs. The key upgrade that would make such missions possible, the workshop report explained, was a reusable heat shield that would enable OTVs to use Earth's atmosphere to slow down and capture into LEO using very little propellant. The report also recommended a lunar base feasibility study and studies of lunar and NEA mining and raw materials processing techniques.

Participants in the La Jolla workshop proposed more than a dozen SDI applications for lunar and asteroid resources. What follows is a description of the top three applications in terms of the mass of lunar and asteroid materials required.

Much of the wide-ranging prospecting, mining, and processing the La Jolla workshop advocated would lead to in-space manufacture of spacecraft "armor" made of lunar aluminum, asteroid iron, and aluminum and iron alloys created by adding small amounts of metals launched from Earth. The workshop report noted that military space systems launched from Earth tended to be made as lightweight as possible to reduce launch costs; this made them fragile and thus vulnerable if attacked.

"On the other hand," the workshop report continued, "if a relatively inexpensive (500-1000 dollars per kilogram) supply of construction materials became available high above Earth, defensive systems would likely be designed very differently, with greater capabilities and greater survivability." Layered armor for an SDI missile-defense platform with a cross-sectional area of 20 square meters would have a mass of about 400 metric tons; 100 such platforms would thus require about 40,000 metric tons of armor.

Layered metal armor would blunt attacks by kinetic-energy weapons (that is, systems that fired solid projectiles); for defense against particle beams or nuclear explosions, however, radiation shielding would be needed. The La Jolla workshop proposed using water from asteroids or (if any existed) from the lunar poles as neutron shielding for vulnerable electronic systems. Water would, of course, also have life support uses, and could be split into liquid oxygen and liquid hydrogen chemical rocket propellants.

After armor, the most important application of space resources in terms of mass was what the La Jolla workshop report dubbed "stabilizing inertia.” An enemy attack might cause a missile-defense platform to spin out of control even if its armor shielded it from damage. Mounting the platform on a chunk of raw asteroid would greatly increase its mass, making it much harder to shove around.

Third after armor and stabilizing inertia were heat sinks. The La Jolla workshop anticipated that missile-defense systems — for example, missile-destroying lasers powered by exploding nuclear bombs — would generate a great deal of waste heat very rapidly. Without places for the heat to go, they could easily destroy themselves. A heat sink might take the form of a large tank of water or large block of metal.

The Fletcher Panel submitted its hefty seven-volume final report to the Reagan White House on 4 November 1983. More than three decades later, most of the Fletcher Report remains classified, so the degree to which the La Jolla workshop influenced its findings is unclear.

Fifteen years into the 21st century, SDI has yet to match Reagan's vision, in no small part part because the Soviet Union — which Reagan dubbed "the evil empire" — collapsed in 1991. Instead of leading to a shield against massive Soviet nuclear attack, SDI became the most important space technology development program since Apollo. Neither the ongoing Discovery Program of cheap, relatively frequent automated lunar and planetary missions nor the low-cost automated Mars missions of the 1996-2008 period would have been possible without the technology infusion from SDI.

Image credit: NASA/USGS.

The pioneer for these missions was Clementine, a joint project of the SDI Organization (later renamed the Ballistic Missile Defense Organization — BMDO), the U.S. Air Force, Lawrence Livermore National Laboratory, the Naval Research Laboratory, and NASA. Stewart Nozette led the Clementine mission. The octagonal 227-kilogram Clementine spacecraft, intended mainly as a BMDO technology demonstrator, lifted off atop a repurposed Titan II missile from Vandenberg Air Force Base on 25 January 1994.

The Clementine spacecraft entered lunar polar orbit on 19 February 1994, where it carried out the first U.S. lunar exploration mission since Apollo 17 in December 1972. It surveyed almost the entire lunar surface for two months. In collaboration with Deep Space Network antennas on Earth, it prospected for ice in the permanently shadowed lunar polar craters. Clementine researchers interpreted data they collected as evidence for large deposits of water ice.

Almost as soon as it was announced at a Department of Defense press conference on 4 December 1996, this interpretation was questioned. Subsequent lunar spacecraft (Lunar Prospector, Chandrayaan-1, LCROSS, and the currently operational Lunar Reconnaissance Orbiter) have, however, confirmed the existence of hundreds of millions of tons of water ice at the lunar poles.

Permanently shadowed areas at the Moon's south pole stand out as a cluster of dark gray voids at the center of this Clementine image mosaic. Image credit: NASA/USGS.

On 5 May 1994, Clementine departed lunar orbit bound for the near-Earth asteroid 1620 Geographos. Geographos, discovered in 1951, is an S-type asteroid, meaning that it is composed mainly of nickel-iron. Radar images of Geographos show it to be extremely elongated (5.1 kilometers long, 1.8 kilometers wide) with pointed ends.

Unfortunately, just two days into its four-month journey, the spacecraft suffered a computer malfunction that caused it to expend all of its attitude-control propellant. The flyby had, incidentally, been the mission's primary goal when spacecraft and mission design began in March 1992; Clementine had been named in reference to the song "Oh, My Darling Clementine" because it would be "lost and gone forever" after it flew past Geographos. The lunar phase of the Clementine mission was added later.

A Clementine 2 asteroid-flyby spacecraft was proposed and studied, but did not receive development funding. Clementine 2 would have flown past near-Earth asteroids 433 Eros and 4179 Toutatis. During the flybys, it would have released impactors, the design of which would have been based on proposed missile interceptors. Instruments on board Clementine 2 based on missile-detection sensors would have recorded the impacts to enable scientists to determine asteroid surface properties. Work on Clementine 2 ceased in 1997.

The fate of Stewart Nozette forms a strange, sad denouement to this story. He was widely celebrated for his work on Clementine: among other awards, he received the NASA Exceptional Achievement Medal. He went on to play roles in the Lunar Reconnaissance Orbiter and Chandrayaan-1 missions. In 2006, 49-year-old Nozette left government service to head up the not-for-profit Alliance for Competitive Technology, which received NASA funding.

Nozette, who had "top secret" security clearance from 1989 to 2006, soon came under Justice Department scrutiny for misappropriation of NASA funds and tax evasion; he was then charged with espionage after attempting to sell classified information to an FBI agent posing as an Israeli spy. In 2011, he was sentenced to 13 years in Federal prison.

Sources

"Ex-White House Scientist Pleads Guilty in Spy Case Tied to Israel," S. Shane, The New York Times, 8 September 2011, p. A22.

"The Clementine Satellite," Energy & Technology Review, Lawrence Livermore National Laboratory, June 1994.

"Reagan is Urged to Increase Research on Exotic Defenses Against Missiles," C. Mohr, The New York Times, 5 November 1983, p. A32.

Defense Applications of Near-Earth Resources, Workshop Held at the University of California, San Diego, Hosted by the California Space Institute, 15-17 August 1983, S. Nozette, editor/workshop organizer, 31 October 1983.

Address to the Nation on Defense and National Security, President Ronald Reagan, 23 March 1983.

More Information

Earth-Approaching Asteroids as Targets for Exploration (1978)

Energy from Space: The 1970s DOE/NASA Solar Power Satellite Studies

An Apollo Landing Near the Great Ray Crater Tycho (1968)

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