The study was based on Martin Marietta work performed under the Marshall Transportation Infrastructure contract, as well as on the Phobos and Mars Case Studies. Bekey's task force briefed Truly on its proposal in the summer of 1989, but it had little obvious influence on The 90-Day Study. 20 Bekey presented the concept at the 40th International Astronautical Federation Congress in Malaga, Spain, in October 1989, just before Truly sent Cohen's report to President Bush.
The Bekey task force proposed that astronauts go first to Phobos. There they would set up an ISRU propellant plant for making propellants from Phobos materials, which are believed to be water-rich. Bekey's group also proposed to minimize impact on Space Station Freedom by using heavy-lift launch vehicles to launch a few large components rather than resorting to on-orbit assembly of many small components. Mission rate would be kept low to reduce spending rate. The piloted Mars expedition would be preceded in the 1990s by a "preparatory program" including automated precursors, technology development, and biomedical research. The Moon played no mandatory role in Bekey's proposed Mars program.
Bekey's task force found that, assuming an opposition-class trajectory with a Venus flyby for the initial Phobos expedition and a conjunction-class trajectory for the Mars landing expeditions, the maximum spacecraft mass at Earth-orbit departure for a Phobos expedition was similar to the minimum mass for a Mars landing expedition—about 700 tons. Therefore, the short Phobos mission in 2004 could act as a "shakedown cruise" for the Mars landing mission spacecraft design, helping to minimize risk to the crew during the longer landing missions.
Three astronauts would travel to Phobos with a piloted Mars lander, which would touch down unpiloted on Mars to act as a backup habitat for the 2007 Mars landing expedition crew. The 2004 crew would spend a month at Phobos, during which they would demonstrate an automated ISRU pilot plant.
Three expeditions would then travel to Mars' surface to set up infrastructure for a Mars outpost. Five astronauts would launch to Mars in 2007, land near the backup habitat from the 2004 mission, and spend a year on the surface. On the next expedition, five astronauts would set up the first half of a propellant production facility on Phobos and land on Mars. Expedition 4 would set up the remainder of the propellant plant, "readying the Mars infrastructure for a sustained series of visits" that would establish a permanent outpost on Mars.
The task force Phobos/Mars spacecraft design consisted of a large dish-shaped aerobrake with twin Space Station Freedom-derived cylindrical habitats. The spacecraft would rely on tethers to create artificial gravity; the astronauts would reel out the habitat modules from the aerobrake, then rotate the assemblage end over end to produce artificial gravity.
Bekey proposed launching Mars ship components and propellant on Shuttle-derived Shuttle-Z rockets, which would include three or four Space Shuttle Main Engines (SSMEs), a strengthened External Tank, and two Solid Rocket Boosters. Shuttle-Z would use existing Kennedy Space Center Shuttle facilities and cost about the same per launch as the Shuttle, "but with 4-6 times the payload." 28
By using the Mars transfer stage as the Shuttle-Z third stage, up to 164 tons could be placed in low-Earth orbit. This would permit the Phobos/Mars spacecraft to be fully assembled with "at most" two Shuttle-Z launches. Three Shuttle-Z launches would refuel the Mars transfer stage in orbit. A similar concept was proposed in the 1971 MSC PMRG study. The crew would then board the ship from a Space Shuttle orbiter and fire the refueled transfer stage to leave Earth orbit for Mars.
The Bekey task force estimated that the total weight launched per year to carry out its Mars program would be about half that needed to carry out the split-sprint mission plan defined by SAIC for the 1987 Ride Report. Bekey's admittedly optimistic preliminary cost estimate was $40 billion for two landings on Mars. 20
The Great Exploration
Alternatives to The 90-Day Study also surfaced outside NASA. In mid-September, at about the time Cohen presented his initial briefing on his study to the National Space Council, Lawrence Livermore National Laboratory (LLNL) engineers, led by Lowell Wood, briefed Quayle on their Great Exploration plan for SEI. 21 LLNL, which was operated by the University of California under contract to the U.S. Department of Energy, was associated with design and test of nuclear weapons, as well as research into advanced particle beam and laser weapon systems.
The Livermore plan was not well received by NASA, which saw it as an effort to invade its territory. 22 The meaning of the "opportunity" Bush mentioned in his 20 July speech thus seemed clear—SEI was to be an opportunity for the national laboratories to expand their bailiwick. According to some participants, one purpose of SEI was to provide work for Federal government agencies and contractors suffering cut-backs because the Cold War was ending. Cohen's study had, in fact, taken into account the need to provide tasks for organizations such as the Army Corps of Engineers and the Department of Energy labs. 23 NASA's understanding was, however, that NASA would be in charge. 24
LLNL's Great Exploration plan drew on its 1985 Columbus lunar and 1988 Olympia Mars studies. 25, 26 Wood and his colleagues explained that their plan respected "contemporary politico-economic realities," which would not tolerate a $400-billion space program lasting three decades. Their plan, they claimed, would require a decade and cost only $40 billion. 27
The Livermore team called for "manned space exploration as though it were a profit-seeking enterprise" with "swift exploration, settlement and infrastructure creation." "Each step," they explained, would leave "major operational legacies—and commitments" so that "Lunar and Martian Bases, once manned, never need be unmanned thereafter." They also called for extensive use of off-the-shelf technology to launch and outfit inflatable structures ("community-sized space suits"), including an Earth-orbital station, "Gas Station" propellant depots, and Moon and Mars surface bases. 28
The Great Exploration program would commence in mid-1992, when a single Titan VI or HL Delta rocket would launch a 50-metric-ton folded Earth Station and Gas Station payload with an Apollo CM on top. The stations would deploy and inflate automatically in orbit under the crew's supervision. The Earth Station would consist of seven 15-meter-long sausage-shaped modules arranged end to end. It would rotate end over end four times each minute to create artificial gravity that would vary from deck to deck over the length of the station, thus providing crews with lunar and Martian gravity experience. The Gas Station would use solar power to electrolyze water into liquid hydrogen/liquid oxygen spacecraft propellants. Water would be launched by competing companies and purchased by the government from the lowest bidder.
In late 1994, a single rocket would launch a 70-metric-ton folded Lunar Base with an Apollo CM-based Earth Return Module on top. The Lunar Base would refuel at the Gas Station, fly to the Moon, and inflate on the surface. The astronauts would live in Spartan conditions, with crew rotation every 18 months. A lunar surface fuel factory and lunar-orbit Gas Station would be established when the second crew arrived in late 1996.
The 70-metric-ton Mars Expedition ship would be launched in late 1996, inflated in Earth orbit, and refueled at the Gas Station. It would then fly to Mars orbit and visit Phobos or Deimos before landing on Mars. The Mars Base would inflate on the surface, and the first crew would move in for a 399-day stay. They would mine Martian water to manufacture propellants for a rocket-powered hopper.
The plan was innovative, but could it work? NASA managers and engineers thought not. The national laboratories, however, had supporters in the White House and on the National Space Council, among them Vice President Quayle. They held up the LLNL proposal as a good example of "innovative thinking." 29
Faced with two rival plans for carrying out his initiative, in December Bush asked the National Research Council (NRC) to examine the studies. H. Guyford Stever, science advisor to Presidents Nixon and Ford and a former Director of the National Science Foundation, chaired the NRC's Committee on Human Exploration of Space. Among its 14 members were Apollo 10 astronaut Thomas Stafford and (until his death on 31 January 1990) Apollo program manager Samuel Phillips.
The Stever Committee report, unveiled on 7 March 1990, stated that the LLNL approach entailed "relatively high risk" and underestimated "the many practical and difficult engineering and operational challenges" of exploring space. 30 The report threw cold water on the push to give SEI over to the national laboratories by stating that "NASA has the organizational expertise and demonstrated capability to conduct human space exploration . . . . To attempt to replicate such expertise elsewhere would be costly and time-consuming." 31
The Stever Committee also pointed out a basic truth applicable to all large space projects: that the "pace at which the initiative should proceed, while clearly influenced by scientific and technical considerations, is inherently determined by social and political decision-making processes in which non-technical constraints, such as the sustainable level of resource commitment and acceptable level of risk[,] are paramount." 32 In other words, policy makers bore as much responsibility for setting SEI's pace, price tag, and chances for eventual success as the engineers, and they would have to make firm decisions before the engineers could plan effectively and proceed.
The Stever Committee then called for more studies, stating that "the [N]ation is at a very early stage in the development" of its Moon and Mars plans (this despite the many studies performed inside and outside NASA over the decades). "None of the analyses to date—The 90-Day Study, The Great Exploration, or, indeed, this report—should be regarded as providing more than a framework for further discussion, innovation, and debate," 33 it stated, then added that " . . . the eventual choice of mission architecture will incorporate the ideas from a variety of concepts, some that now exist and others that will arise in the future . . . . The variety of concepts should be regarded as a 'menu' of opportunities." 34
In late February, a week before the Stever Committee report was publicly released, President Bush directed that NASA should be the "principal implementary agency" for SEI, with the Departments of Defense and Energy in "major roles." 35 Within a week of the report's release, President Bush followed its advice and called for more study. He asked that at least two substantially different reference architectures for SEI be produced over the next several years.
Idea collection for the Stever Committee's "menu" had begun in mid-January 1990, when the Aerospace Industries Association, an organization representing aerospace contractors, had met to start a process of gathering ideas to turn over to NASA. The Agency's Office of Aeronautics and Space Technology served as ad hoc coordinator for this effort. 36 NASA also enlisted Rand Corporation to manage a campaign to solicit ideas from industry, universities, national labs, and the general public. NASA Administrator Truly led a U.S. Government interagency effort. This broad gathering of ideas became known as the SEI Outreach Program.
Ideas collected through the Outreach Program were to be reviewed by an independent SEI Synthesis Group, which would then issue a report. The Synthesis Group approach had been recommended by the Aerospace Industries Association in April. On 16 May 1990, Congress agreed to provide $4.55 million for the Outreach Program, but not without a price. NASA had to agree that it would release no SEI-related contracts to industry until 1991. As one congressional staffer explained, this deferment was designed "to avoid raising expectations in the private sector, given the incredible [Federal] budget restraints." The Agency also agreed to defer $5 million in internal NASA study work until 5 August 1990. 37 On 31 May, Truly introduced Tom Stafford as Synthesis Group chair.