The Planetary Society
In 1983, The Planetary Society, a non-profit space advocacy organization with about 100,000 members, commissioned the most detailed piloted Mars mission study since 1971. The organization did this because, as Society president Carl Sagan and executive director Louis Friedman wrote in their foreword to the study report, "since Apollo, there have been, in the United States at least, almost no serious studies of manned (or womanned) voyages to other worlds, despite the fact that enormous technological advances have been made since those early lunar landings." 8 Writing in the Society's member magazine, The Planetary Report, Friedman explained that "we funded [the study] because it is important to have solid technical evidence to back us in our advocacy of new goals . . . ." 9 The nine-month study, "a labor of love" performed at a "bargain basement price" by Science Applications International Corporation (SAIC), was completed in September 1984. 10
SAIC's Mars mission design resembled MSC's 1963 Flyby-Rendezvous mode. Eighteen Space Shuttle launches would deliver more than 160 metric tons of spacecraft components to Earth orbit. The four-person crew would travel to Mars in a 121-metric-ton Outbound Vehicle consisting of four "sub-vehicles." These were the 38-metric-ton Interplanetary Vehicle, the 19-metric-ton Mars Orbiter, the 54-metric-ton Mars Lander, and the 10-metric-ton Mars Departure Vehicle.
The Interplanetary Vehicle, which would provide one-quarter of Earth's gravity by spinning three times each minute, would include pressurized crew modules based on Spacelab modules. The Mars Orbiter, the Mars Departure Vehicle, and the conical, two-stage Mars Lander were together designated the Mars Exploration Vehicle (MEV). The MEV would include a 54-meter-diameter aerobrake. The crew would return from Mars in the 43-metric-ton Earth Return Vehicle (ERV), which resembled the Interplanetary Vehicle except in that it would include a conical 4.4-metric-ton Earth-return capsule nested in a 13-meter-diameter aerobrake. Of these vehicles, only the MEV would have to slow down and enter Mars orbit. This, plus extensive use of aerobraking, would reduce the amount of propellant required to carry out SAIC's Mars expedition, which in turn would reduce spacecraft weight.
The unpiloted ERV would depart Earth orbit on 5 June 2003, using three large OTVs stacked together, each carrying over 27 metric tons of propellants. The SAIC team assumed that reusable space-based OTVs would be available in Earth orbit as part of NASA's Space Station Program. The expense of developing, launching, and operating the OTVs was thus not counted in the cost of the expedition. OTV 1 would fire its engines at perigee, increasing its apogee distance, then separate. OTV 2 would repeat this procedure. OTV 3's perigee burn would place the ERV on course for Mars. This series of maneuvers would require about six hours.
The crew would depart Earth in the Outbound Vehicle ten days later, on 15 June 2003. Because it was nearly three times heavier than the ERV, the Outbound Vehicle would need perigee burns by seven OTVs over about two days to achieve a Mars-bound trajectory.
On 24 December 2003, the crew would near Mars in the Outbound Vehicle, board and undock the MEV, and aerobrake into Mars orbit. The abandoned Interplanetary Vehicle would fly past Mars into solar orbit. Three of the four crew would enter the Mars Lander and descend to the surface, which they would explore using a pressurized rover. On 23 January 2004, after a month on Mars, the surface crew would lift off in the Mars Lander ascent stage with 400 kilograms of rock samples to rejoin their colleague aboard the Mars Orbiter.
The ERV, meanwhile, would approach Mars on a flyby trajectory. The crew would board the Mars Departure Vehicle, abandon the Mars Lander ascent stage and Mars Orbiter, and leave Mars orbit in pursuit of the ERV. Rendezvous and docking would occur while the ERV was outbound from Mars. Friedman noted that "[b]ecause the orbit doesn't close around Mars, the crew has only a chance at one precise time, to rendezvous with the return vehicle. Although this is risky, SAIC analysis found it acceptable compared to other mission risks. (However, some of us at The Planetary Society wonder if the crew will feel the same way!)" 11
Eighteen months later, on 5 June 2006, the crew would board the Earth-return capsule and separate from the ERV. They would aerobrake in Earth's atmosphere while the abandoned ERV flew past Earth into solar orbit.
The SAIC team estimated the cost of their Mars expedition at $38.5 billion in 1984 dollars, of which $14.3 billion would be spent on Mars spacecraft hardware, $2 billion would pay for Shuttle launches, and $18.5 billion would be spent on operations. Friedman pointed out that, over a decade, this cost averaged about $4 billion annually, or about 60 percent of NASA's approximately $7-billion FY 1984 budget. 12
Chapter 7: The Case for Mars
Space Station
Traditionally, space stations have been envisioned as having multiple functions, not least of which was as an assembly and servicing base—a spaceport—for spacecraft, including those bound for Mars. In 1978, as Space Shuttle development moved into its final stages, NASA's Johnson Space Center (JSC) (as MSC was renamed in 1973) began planning a Shuttle-launched modular space station called the Space Operations Center (SOC). A space shipyard, the SOC was the most important station concept in the years 1978 through 1982—the period immediately before gaining approval for a station became a realistic goal for NASA. 13
An internal NASA presentation in May 1981—one month after STS-1—described the SOC as the central element of a "space operations system" that would include the Space Shuttle, OTVs for moving objects assembled at the SOC to orbits beyond the Shuttle's altitude limit, and Manned OTVs for transporting astronauts on satellite service calls. 14 A JSC press release in early 1982 referred to the SOC as a "space base and marshaling yard for large and complex payloads" providing "garage space for reusable cryogenic stages." 15
After his first year in office, during which NASA took deep cuts, President Ronald Reagan came to see the political benefits of being identified with a successful space program. On 4 July 1982, Columbia returned from space at the end of mission STS-4. Reagan was on hand amid fluttering American flags to declare the Shuttle operational. He spoke of establishing a more permanent presence in space, but withheld a clear mandate to build a space station until his 25 January 1984 State of the Union address. When he did, he emphasized its laboratory function:
We can follow our dreams to distant stars, living and working in space for peaceful economic and scientific gain. Tonight I am directing NASA to develop a permanently manned Space Station and to do it within a decade. The Space Station would permit quantum leaps in our research in science, communications, in metals and in life-saving medicines which can only be manufactured in space . . . . 16
The lab function was emphasized partly to keep the Station's estimated cost as close to $8 billion as possible. 17 As we have seen, Mars planners early in the 1980s assumed that OTVs and other Earth-orbit infrastructure applicable to Mars exploration would soon become available. With the spaceport role de-emphasized and the lab role moved to the fore, the justification for OTVs was largely removed, and the ability to assemble other Earth-orbit infrastructure, such as Singer's solar array, was made forfeit. Assembling the Space Station itself would provide some experience with application to Mars ship assembly. However, it would provide little experience with handling tankage and propellants in space, both crucial to building a Mars ship.
Soviets to Mars
In the early 1980s, such NASA advanced planning as existed focused more on the Moon than on Mars. The revival in NASA Mars interest owes much to geologist and Apollo 17 Moonwalker Harrison Schmitt, and to the Agency's lunar base studies, which had never receded to the same degree as its Mars studies. Schmitt was concerned about an on-going Soviet space buildup, which saw long stays by cosmonauts aboard Salyut space stations and development of a Soviet shuttle and heavy-lift rocket, as well as plans for ambitious robotic Mars missions. 18 Schmitt also concentrated on Mars because he had asked children, the future space explorers, about returning to the Moon and found that they were not interested because people had already been there. 19
Schmitt had attempted to promote Mars exploration in the late 1970s while serving as Republican U.S. Senator from New Mexico. Following Viking's success, he had put forward a bill calling for the U.S. to develop the capability to establish a settlement on Mars by 2010. His "Chronicles Plan" excited momentary interest in President Jimmy Carter's White House, inducing NASA Administrator Robert Frosch to activate a small NASA study team. The team's July 1978 workshop at Wallops Island, Virginia, produced nothing new. In fact, the consensus was that "past work [from the 1960s] should not be updated unless serious consideration is being given to conducting a manned Mars mission prior to the year 2000." 20 In short, NASA was too busy working on the Space Shuttle in 1978 to think about Mars.
Schmitt renewed his Mars efforts in 1983 by contacting Paul Keaton of LANL during a meeting held in the runup to the 1984 Lunar Bases and Space Activities of the 21st Century conference, held at the National Academy of Sciences in Washington, DC. 21 As seen in Chapter 5, LANL was involved in space flight before NASA was created through its work on nuclear rockets. At the lunar base conference, Schmitt presented a paper on his "Mars 2000 Millennium Project," which he hoped would "mobilize the energies and imaginations of young people who are already looking beyond Earth orbit and the Moon." 22 He also made contact with NASA engineers and scientists interested in exploring Mars as well as the Moon. 23
Schmitt then pressed for a study to give the President the option to send humans to Mars should he desire to respond to the Soviet buildup. LANL partnered with NASA to conduct the Manned Mars Mission (MMM) study during 1984 and 1985. The effort culminated in the joint NASA-LANL MMM workshop at NASA Marshall (10-14 June 1985). 24 The workshop published three volumes of proceedings in 1986. 25
Figure 18—In 1985, NASA's Johnson Space Center responded to suspected Soviet Mars plans by proposing a U.S. Mars flyby using Space Station and lunar base hardware then planned for the 1990s. Here the flyby spacecraft orbits Earth before setting out for Mars. ("Concept for a Manned Mars Flyby," Barney Roberts, Manned Mars Missions: Working Group Papers, NASA M002, NASA/Los Alamos National Laboratories, Huntsville, Alabama/Los Alamos, New Mexico, June 1986, Vol. 1, p. 210.)
<!-- image -->Especially noteworthy, given Schmitt's primary rationale for the MMM workshop, was a JSC plan for a piloted Mars flyby based on technology expected to exist in the 1990s as part of the Space Station Program. This aimed at countering a possible Soviet piloted Mars flyby mission.
In April 1985, at Schmitt's request, the CIA prepared an analysis of possible Soviet space moves. The analysis cited "[p]ublic comments in 1982 by the Soviet S[cience] & T[echnology] Attaché assigned to Washington and in 1984 by the President of the Soviet Academy of Science," which suggested that "the Soviets have confidence in their ability to conduct such a mission." The CIA then predicted that " . . . they will choose a one-year flyby as their first step." 26
The analysis cited current and future indicators pointing to Soviet piloted Mars exploration. These included continuing work on a heavy-lift rocket "capable of placing into low-earth orbit about five times the payload of the present largest Soviet space launch vehicle, thereby significantly reducing the number of launch vehicles required." 27 The "strongest current indicator," however, was "the long-duration stays in space by cosmonauts" aboard Salyut space stations. Potential future indicators included "a cosmonaut stay in low-earth orbit of one year duration . . . [and] space tests of a nuclear propulsion system . . . ." 28 The CIA guessed that the first Soviet Mars flyby might occur as early as 1992, in time for the 500th anniversary of Columbus's arrival in the Americas. 29