18 November 2016

"Essential Data": A 1963 Pitch to Expand NASA's Robotic Exploration Programs

The derelict Surveyor 3 lander (left) became a pin-point landing target for Apollo 12 in November 1969. Image credit: NASA
The Apollo Program dominated NASA in the 1960s. Its chief aim was to place a man on the moon ahead of the Soviet Union and before 1970. In December 1963, three of NASA's four approved robotic exploration programs – Ranger, Surveyor, and Lunar Orbiter - focused on the moon. The fourth, Mariner, aimed at Mars and Venus. Apollo requirements - the need to find safe landing sites and to understand lunar conditions well enough to design the Apollo Lunar Excursion Module lander - dominated the moon programs. Beating the Communists to Venus and Mars was a major motivator for Mariner. In short, Cold War geopolitics ruled, not scientific exploration.

On 2 December 1963, NASA Lunar and Planetary Program staffers briefed NASA top brass (Administrator James Webb, Deputy Administrator Hugh Dryden, and Associate Administrator Robert Seamans) with the aim of shifting NASA’s robotic program priorities toward science.

In his introductory presentation, Lunar and Planetary Program Director Oran Nicks solicited funding to enhance the four extant programs with new science-focused missions. He also sought funding to initiate the new Voyager Mars/Venus program.

Nicks reminded Webb, Dryden, and Seamans that Mariner II had scored an impressive first by flying past Venus in December 1962. He noted that, one year after achieving world's first successful planetary flyby, NASA's entire approved planetary program consisted of just two Mars flybys (Mariners III and IV, set for launch in November 1964). Mariner missions planned after 1964 were, he stressed, "not firm." He blamed funding cuts and persistent problems with the finicky cryogenic liquid hydrogen/liquid oxygen Centaur upper stage for this surprising failure to follow up on Mariner II's success. Nicks then turned the briefing over to his Lunar and Planetary Program managers.

By the time Ranger Program Manager N. William Cunningham stood before Webb, Dryden, and Seamans, Rangers I through V had failed. Ranger I (launched 23 August 1961) and Ranger II (launched 18 November 1961), "Block I" vehicles meant to gather data on micrometeoroids, radiation, solar plasma, and magnetic fields in high elliptical Earth orbit, had fallen victim to Atlas-Agena B rocket malfunctions, as had Ranger III (launched 26 January 1962), a Block II spacecraft meant to rough-land on the moon a spherical balsa-wood capsule bearing a seismometer. Ranger IV (launched 23 April 1962) and Ranger V (launched 18 October 1962), also Block IIs, had suffered electrical failures.

The Block II Ranger spacecraft with spherical balsa-wood "lunar capsule." The solid-propellant retrorocket was intended to ignite during the final seconds of the spacecraft's flight, slowing the capsule so that it could make a survivable rough landing on the moon. Image credit: NASA 
Cunningham began his presentation by telling Webb and his deputies that Ranger VI, a Block III spacecraft designed to snap photos of the moon while plummeting toward destructive impact, would launch in January 1964. He assured them that his engineers had made "many changes in. . .the spacecraft. . .in an effort to improve its chances for success."

Four Block IIIs (Rangers VI through IX) were expected to photograph the moon by August 1964, then six Block Vs (Rangers X through XV) would fly in 1965-1967. Cunningham noted that NASA planned to spend $92.5 million on Block V Rangers. Much like the Block IIs, Block V Rangers would attempt to rough-land capsules containing instruments, including possibly a TV system for beaming to Earth images from the moon's stark surface. Cunningham called the Block Vs "the only backup" the U.S. had in place for the Surveyor Program, then urged Webb and his lieutenants to add $50 million to the Block V Ranger development budget.

Surveyor 1 Atlas-Centaur rocket liftoff, 30 May 1966. The three-legged Surveyor soft-landed on 2 June 1966 within the Flamsteed Ring, an ancient crater mostly inundated by lava flows that formed the moon's Oceanus Procellarum. The lander returned data during lunar daylight periods, when its single solar panel could make electricity to operate its instruments and radio. Surveyor 1 outlasted its expected lifespan: contact was not lost until 7 January 1967. Image credit: NASA
Surveyor Program Manager Benjamin Milwitzky took the floor next. He told Webb, Dryden, and Seamans that his program's main purpose was to gather "essential data about the lunar surface. . .needed for manned landings." An Atlas-Centaur rocket would launch the first Surveyor soft-lander in 1965. Milwitzky reported that Surveyor had been intended to carry 300 pounds of science instruments, but that Centaur upper stage problems had forced a cut to between 70 and 100 pounds. He told them that, while the reduced payload would be adequate for scouting Apollo landing sites, many lunar science opportunities would have to be abandoned - unless NASA took action.

Milwitzky proposed that Surveyor's science payload be restored by adding the corrosive element fluorine to the Atlas rocket's liquid oxygen propellant. He urged Webb, Dryden, and Seamans to spend $40 million in 1964-1966 to develop this energetic oxidizer mix for the Atlas.

If they agreed to beef up the Atlas, then the first advanced science-focused Surveyor could fly in 1967. A typical advanced Surveyor lander might include a Radioisotope Thermoelectric Generator to provide its instruments with long-term electricity, a drill for subsurface sample collection, on board sample analysis gear, a geophysical probe that could be lowered down the drill bore hole, a seismometer, a mast-mounted TV system for imaging a large area around the lander in stereo, and a small rover for exploring the landing site and emplacing explosive seismic experiment packages a safe distance away from the lander.

Milwitzky ended his presentation by proposing that NASA increase the number of planned Surveyor missions from 17 to 29. He estimated that the 17-mission program would cost $425.5 million; adding 12 more missions would cost an additional $352 million.

Milwitzky then handed off to Lee Scherer, Lunar Orbiter Program Manager. Scherer began his presentation by reminding Webb and his deputies that Lunar Orbiter missions 1 through 5 had been approved for 1966-1967, and that Lunar Orbiters 6 through 10, while not yet formally approved, were planned for 1967-1968. Lunar Orbiter spacecraft would, he said, aim "to obtain, initially, scientific data about the moon and its environment of special importance to the Apollo mission." The approved Lunar Orbiters were intended mainly to photograph areas of the lunar surface accessible to Apollo spacecraft (that is, close to the equator on the Nearside, the lunar hemisphere that forever faces Earth).

Scherer proposed that NASA fly five science-oriented Lunar Orbiters in 1968-1969. These might enter orbits inclined to the lunar equator, enabling them to pass over scientifically interesting surface features beyond the equatorial Apollo landing zone. They might also enter lunar polar orbit for whole-moon mapping. Gamma-ray spectrometers and infrared sensors might be used to map lunar mineralogy. Scherer also proposed a mission dedicated to exploring moon/Sun plasma interactions and any lunar magnetic field that might exist. Lunar Orbiters 1 through 10 would cost $198 million; Scherer estimated that adding Lunar Orbiters 11 through 15 would boost the program's cost by $95 million.

The Jet Propulsion Laboratory (JPL) in Pasadena, California, first proposed the ambitious Voyager Mars/Venus robotic spacecraft series in 1960. In December 1963, Voyager was not yet an approved NASA program, though studies continued at JPL and NASA Headquarters. According to Donald Hearth, the Lunar and Planetary Program Office staffer responsible for Voyager, NASA had allotted $7.1 million for Voyager studies in 1962-1963. Of this, all but $1.3 million had been shifted to cover funding shortfalls in other programs.

The Voyager spacecraft design as of mid-1967. The lander, bundled up in a conical black Mars atmosphere entry capsule and a back-shell, is visible on the spacecraft at upper right. Solar arrays form a flat ring around Voyager's protruding rocket motors and a skeletal high-gain radio antenna points toward Earth. Image credit: NASA
Assuming that Congress approved its development, the Voyager spacecraft would comprise three parts: a 2000-pound orbiter with a 2000-pound retro stage and a 2500-pound lander. These would leave Earth together on a two-stage Apollo Saturn IB rocket augmented by a Centaur third stage. For Mars missions, the Voyager lander would separate from its orbiter during approach to the planet, enter the atmosphere directly from its interplanetary trajectory, and land within 500 kilometers of a target site. It would explore its landing site for six months. After lander separation, the Voyager orbiter would fire the retro stage to slow down so that Mars's gravity could capture it into orbit.

Hearth told Webb, Dryden, and Seamans that the Voyager 1969 Mars lander would carry an impressive suite of 38 science instruments, including two TV cameras, a sample-collection drill, biology detectors, a microscope, a seismometer, a microphone, and meteorology sensors. Voyager 1969 Mars orbiter instruments would include multicolor stereo TV cameras, an infrared spectrometer for determining surface composition over wide areas, a magnetometer for charting the martian magnetic field, a cosmic dust detector, and a solar X-ray detector.

Though more capable than any other U.S. lunar or planetary spacecraft, the Saturn IB/Centaur-launched Voyagers would pale next to planned Saturn V-launched Advanced Voyagers. Hearth reported that the Saturn V rocket could launch to Mars a 3100-pound orbiter and one or more direct-entry landers weighing a total of 33,000 pounds.

These "large lander laboratories" might include rovers, balloons, and hovercraft to enable exploration beyond their landing sites. Alternately, the Advanced Voyager orbiter might carry a large retro stage that would enable it to retain its lander until after it achieved Mars orbit. Lander descent from Mars orbit would improve landing accuracy, Hearth explained.

Hearth estimated that the Voyager Program would cost $2.9 billion over 11 years. Assuming timely approval, NASA could launch Voyager test flights in 1967 and 1968, Voyager Mars missions in 1969, 1971, and 1973, Voyager Venus missions in 1970 and 1972, and Advanced Voyager Mars missions in 1973 and 1975.

Within a week of the 2 December 1963 briefing, James Webb informed Oran Nicks that NASA could not afford to expand its robotic lunar and planetary programs in support of science. In fact, by 13 December, when NASA Associate Administrator for Space Sciences and Applications Homer Newell announced that the Block V Ranger development was cancelled, it had become clear that NASA would cut back its robotic lunar programs, sharply limiting opportunities for science-focused missions. Ranger, Surveyor, and Lunar Orbiter became victims of their own success; almost as soon as they proved themselves to be capable scientific exploration machines by providing the data Apollo engineers and planners needed, NASA top brass opted to end them and move on.

In all, scientists were granted just four robotic missions specifically for scientific lunar exploration. Though Ranger VI was an embarrassing failure, Rangers VII and VIII succeeded, and the program concluded with the successful science-focused Ranger IX mission to Alphonsus crater in March 1965. All were Block III spacecraft. Five Lunar Orbiters mapped the moon between August 1966 and January 1968. Lunar Orbiters 4 and 5 were science-focused missions in a near-polar lunar orbits. Surveyor ended with its seventh flight, a science-focused mission to a site just north of the bright ray crater Tycho in January 1968.

After Apollo, NASA received data from instruments left behind on the moon by the Apollo astronauts. These were turned off in September 1977. The U.S. civilian space agency then largely abandoned the moon, scene of its greatest triumph, until 1994, when it conducted the Clementine mission in cooperation with the Department of Defense Ballistic Missile Defense Organization. Clementine, a technology test-bed, orbited the moon for about 10 weeks. It shared little or no design heritage with earlier NASA lunar spacecraft.

Mariner 9 carried a large propellant supply (hidden beneath the white cover) so that it could slow down and capture into Mars orbit. It left Earth on an Atlas-Centaur rocket on 30 May 1971 and became the world's first planetary orbiter on 14 November 1971. Image credit: NASA

Mariner 10 left Earth on 3 November 1973 and flew past Venus on 5 February 1974. Using Venus's gravity and orbital motion, it performed the world's first gravity-assist planetary flyby. This placed it on course for a trio of Mercury flybys in 1974-1975. Image credit: NASA
The 1960s and 1970s saw a total of seven successful Mariners and four successful Mariner-derived planetary spacecraft. In July 1965, Mariner IV became the first spacecraft to fly past Mars. No Mariner ever carried an atmosphere probe, but Mariner 9 (May 1971-October 1972) became the first Mars orbiter (and, indeed, the first planetary orbiter in history). Mariner 10, officially the last spacecraft of the Mariner series, became the first to fly past Mercury (in fact, it flew by the planet three times, in March 1974, September 1974, and March 1975).

Voyager became an official NASA program in 1965, just in time to see its design scrapped and its estimated cost nearly doubled. Mariner IV was the culprit: it revealed that the planet's atmosphere was 10 times thinner than expected. Because of this, Voyager would need heavy landing rockets in addition to parachutes.

The star-crossed program lingered on until August 1967, when Congress refused to fund its continued development. NASA then proposed a cut-price Mariner-derived Mars landing program, called Viking, which received approval in 1968 from a Congress increasingly aware of Soviet claims of plans to explore the Solar System with automated rovers and sample-returners . Two Viking orbiter-lander pairs explored Mars beginning in 1976. The name Voyager was subsequently resurrected for twin Mariner-derived outer planets flyby spacecraft - originally named Mariner Jupiter-Saturn - which departed Earth in 1977.

Viking Orbiter 1 releases Viking Lander 1 in Mars orbit, 20 July 1976. The Lander (below) is stowed inside an aeroshell; a bioshell for protecting the Lander from terrestrial contamination after it was sterilized remains attached to the Orbiter, which resembles Mariner 9. Image credit: NASA
Of all the Mariner-derived spacecraft launched, only the most distant remain functional. Voyager 1 flew past Jupiter (1979) and Saturn (1980); Voyager 2 conducted a grand tour of Jupiter (1979), Saturn (1981), Uranus (1986), and Neptune (1989). At this writing, Voyager 1 is located 137.6 Astronomical Units (AU) from Earth, while Voyager 2 is 113.3 AU from Earth. (An AU, the distance from the Sun's center to the Earth's center, iapproximately 149.6 million kilometers.) Image credit: NASA


"Briefing for the Administrator on Possible Expansion of Lunar and Planetary Programs," NASA Headquarters, 2 December 1963

Astronautics and Aeronautics, 1963, NASA SP-4004, 1964, p. 477

Lunar Impact: A History of Project Ranger, NASA SP-4210, R. Cargill Hall, NASA, 1977

The Voyage of Mariner 10: Mission to Venus and Mercury, NASA SP-424, James A Dunne & Eric Burgess, NASA, 1978

On Mars: Exploration of the Red Planet, 1958-1978, NASA SP-4212, Edward Clinton Ezell & Linda Neuman Ezell, NASA, 1984

Deep Space Chronicle: A Chronology of Deep Space and Planetary Probes 1958-2000, NASA SP-2002-4524, Monographs in Aerospace History Number 24, Asif A. Siddiqi, 2002, pp. 88-90, 105-106, 110-112

Voyager: The Interstellar Mission - http://voyager.jpl.nasa.gov/ (accessed 19 November 2016)

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The Challenge of the Planets, Part Three: Gravity

A 1974 Plan for a Slow Flyby of Comet Encke

Missions to Comet d'Arrest & Asteroid Eros in the 1970s (1966)

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


  1. Back in the 60's my grandfather had years of National Geographic magazine on the shelf and I loved to paw through anything they did on space. They did an awesome article on the Block II Ranger that was supposed to land the balsawood ball on the moon. There were very exciting painted illustrations of the probe flying away from the Ranger and rolling to a stop on the moon. Was not till many years later that I learned that the mission was a failure..ah shucks. It was quite an article.

  2. I remember that issue, too. I used to fling a tether ball around the yard, pretend it was a Ranger landing capsule. I think I frightened the neighbors.



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