On 22 July 1987, Ride testified to the House Subcommittee on Space Science and Applications. She told the Subcommittee that the "civilian space program faces a dilemma, aspiring toward the visions of the National Commission on Space, but faced with the realities of the Rogers Commission report." 12 Ride explained that she had attempted to reconcile "two fundamental, potentially inconsistent views." "Many people," she said, believed that "NASA should adopt a major visionary goal. They argue that this would galvanize support, focus NASA programs, and generate excitement." Others, Ride stated, maintained that NASA was "already overcommitted for the 1990s"—that it would be "struggling to operate the Space Shuttle and build the Space Station, and could not handle another major program." 13
While Paine's NCOS report urged rapid implementation of an expansive vision, Ride's report outlined four more limited leadership initiatives "as a basis for discussion." She explained that her report was "not intended to culminate in a selection of one initiative and elimination of the other three, but rather to provide concrete examples which could catalyze and focus the discussion of the goals and objectives of the civil space program, and of NASA efforts required to pursue them." 14
Ride thus deviated from the pattern Paine had established in the STG report and continued in the NCOS report; she did not propose a single "master plan." In her congressional testimony she explained her guiding principle: "goals must be carefully chosen to be consistent with the national interest and . . . NASA capabilities. It is not appropriate for NASA to set the goals of the civilian space program. But NASA should lead the discussion . . ., present options, and be prepared to make recommendations." 15 Ride's four Leadership Initiatives were as follows:
- Mission to Planet Earth: "a program that would use the perspective afforded from space to study . . . our home planet on a global scale."
- Solar system exploration using robots.
- Outpost on the Moon: an ". . . evolutionary, not revolutionary . . . program that would build on . . . the legacy of the Apollo Program . . . to continue exploration, to establish a permanent scientific outpost, and to begin prospecting the Moon's resources."
- Humans to Mars: "a series of round trips to land on the surface of Mars, leading to the eventual establishment of a permanent base." The Mars mission, Ride asserted, should "not be another Apollo—a one-shot foray or a political stunt." 16
None of Ride's four initiatives necessarily depended on the others. Her "attempt to crystallize our vision of the space program in the year 2000" in fact represented a partial break from the space station-Moon-Mars progression that had typified most NASA advanced planning. 17 Ride's approach caused confusion. For example, Aviation Week & Space Technology magazine and many newspapers incorrectly reported that she had called for a Moon base as a precursor to a piloted Mars mission. In fact, her report stated that the Moon was "not absolutely necessary" as a "stepping stone" to Mars. 18, 19
This reflected the influence of a NASA Advisory Council Task Force led by Apollo 11 astronaut Michael Collins. "I think it is a mistake to consider the Moon as a necessary stepping stone to Mars," Collins told Aviation Week & Space Technology in July. "It will not get support politically, or from the U.S. public, which thinks we've 'already done the Moon.'" 20 Ride personally favored the Moon-Mars progression, however; she wrote that it "certainly makes sense to gain experience, expertise, and confidence near Earth first." 21
In common with the station-Moon-Mars progression, Ride's initiatives all included NASA's Space Station. This was a ground rule established by Fletcher—not surprisingly, since the Space Station Program had begun only three years before and was fiercely defended by NASA. 22 As explained earlier, in Challenger's aftermath, Space Station had become a two-phase program. Ride pointed out that a decision on NASA's future course would impact the Phase II configuration. She wrote that a "key question for the not-too-distant future is 'how should the Space Station evolve?'" and noted that Space Station evolution workshops in 1985 and 1986 had found that "a laboratory in space featuring long-term access to the microgravity environment might not be compatible with an operational assembly and checkout facility [of the type envisioned to support Moon and Mars exploration], as construction operations could disturb the scientific environment." 23
Like the NCOS report, Ride's report called for NASA to increase its efforts to develop advanced space technology for exploration missions. She told the House Subcommittee that "the future of our space program lies in careful selection and dedicated pursuit of a coherent civil space strategy, and the health of our current space program lies in determined development of technologies required to implement that strategy." 24 Ride's report recommended Project Pathfinder, a program to develop technologies that had been identified by a panel of NASA engineers as crucial to future space programs. These included aerobraking, automated rendezvous and docking, and advanced chemical propulsion. "Until advanced technology programs like Pathfinder are initiated" wrote Ride, "the exciting goals of human exploration will always remain 10 to 20 years in the future." 25
On 1 June 1987, Fletcher had created the NASA Headquarters Office of Exploration, with Ride as Acting Assistant Administrator for Exploration, responsible for coordinating missions to "expand the human presence beyond Earth." In explaining this move, Fletcher said that "[t]here are considerable—even urgent—demands for a major initiative to reenergize America's space program . . . this office is a step in responding to that demand." 26 In her report, Ride wrote that "[e]stablishment of the Office of Exploration was an important first step. Adequate support of the Office will be equally important." She noted that there was "some concern that the office was created only to placate critics, not to provide a serious focus for exploration. Studies relating to human exploration of the Moon or Mars currently command only about 0.03 percent of NASA's budget . . . this is not enough . . . ." 27
Ride targeted the first Mars landing for 2005. Her report pointed out, however, that "NASA's available resources were strained to the limit flying nine Shuttle flights in one year." "This suggests," it concluded, "that we should . . . proceed at a more deliberate (but still aggressive) pace, and allow the first human landing to occur in the 2010 timeframe." 28 Ride left NASA soon after her report was published to take a position at Stanford University.
Ride's report was well received, primarily because it was seen as a realistic assessment of NASA's situation. It was not, however, a plan for NASA to follow. It was, as Ride said, a basis for discussion. The discussion it catalyzed would continue through the end of the 1980s.
occur in 2010. This spreads the investment over a longer period." 28
SAIC began designing the Mars mission in Ride's report in January 1987 and completed its study for the NASA Headquarters Office of Exploration in November 1987. 29 John Niehoff, the study's Principal Investigator, was the "Humans to Mars Initiative Advocate" for the Ride Report. He had also worked on The Planetary Society's 1984 Mars study (see Chapter 7). Niehoff's team proposed a three-part Mars exploration strategy:
- 2000s: Piloted missions with round-trip times of about one year, stay-times near Mars of 30 to 45 days, and Mars surface excursions of 10 to 20 days were the primary emphasis of the SAIC study. These missions would explore potential outpost sites and build up interplanetary flight experience. The one-year trip-time was designed to reduce crew exposure to weightlessness and radiation.
- 1990s: Robotic missions, including a global mapper and a sample-return mission, would "address key questions about exobiology and obtain ground-truth engineering data." This period would also see research aboard the Space Station into the effects of prolonged weightlessness on astronaut health, and development of "heavy-lift launch vehicles, high energy orbital transfer stages, and large-scale aerobrakes."
- After 2010: "A piloted base on Mars . . . a great national adventure which would require our commitment to an enduring goal and its supporting science, technology, and infrastructure for many decades." 30
A large amount of energy would be required to get the ship to Mars and back in about a year, which in turn would demand a prohibitively large amount of propellant. With an intent to reduce the number of heavy-lift rocket launches needed to mount the expedition, SAIC adopted a split/sprint mission mode based on a design developed by students from the University of Texas and Texas A&M University. This had a one-way, automated cargo vehicle leaving Earth ahead of the piloted sprint vehicle on a low-energy trajectory. The cargo vehicle would carry Earth-return propellants for the piloted ship. To some this was worrisome—if the sprint spacecraft could not rendezvous and dock with the cargo vehicle, the crew would become stranded at Mars with no propellants for return to Earth. 31
Figure 21—Science Applications International Corporation developed its Mars mission plan for NASA during 1987. The piloted spacecraft (shown here in cutaway) would reach Mars with empty propellant tanks and dock with a waiting automated cargo ship to fill up for the trip home—a controversial departure from past Mars plans. (Piloted Sprint Missions to Mars, Report No. SAIC-87/1908, Study No. 1-120-449-M26, Science Applications International Corporation, Schaumburg, Illinois, November 1987, p. 9.)
<!-- image -->Chapter 8: Challengers
In phase 1 of SAIC's four-phase Mars mission, seven heavy-lift rockets would launch parts for the cargo vehicle and a reusable OTV, propellants, and cargo into orbit near the Space Station. The OTV and cargo vehicle together would measure 30.5 meters long and weigh 58.8 metric tons fully fueled. In addition to Earth-return propellants for the piloted sprint vehicle, the 23.9-metric-ton cargo vehicle would carry the Mars lander and scientific equipment.
Figure 22—Two Orbital Transfer Vehicles would push the Science Applications International Corporation piloted Mars ship out of Earth orbit. The company assumed that Orbital Transfer Vehicles would be built for non-Mars programs in time to support its expedition, slated to reach Mars in 2005. (Piloted Sprint Missions to Mars, Report No. SAIC-87/1908, Study No. 1-120-449-M26, Science Applications International Corporation, Schaumburg, Illinois, November 1987, p. 27.)
<!-- image -->According to SAIC's timetable, on 9 June 2003 the OTV would push the cargo ship onto a minimum-energy Mars trajectory, then separate and aerobrake in Earth's atmosphere to return to the Space Station for reuse. The cargo ship would aerobrake into Mars orbit on 29 December 2003.
Phase 2 would start one year after phase 1. Eight heavy-lift launch vehicles would place propellants and components for the piloted sprint vehicle and a second OTV into Earth orbit near the space station. The OTV used to launch the cargo vehicle would be combined with the new OTV and the sprint vehicle to create a 73.9-metric-ton, 47.5-meter-long stack. The sprint vehicle alone would weigh 19.4 metric tons fully fueled.
SAIC's sprint vehicle design was based on a 24.4-meter-diameter saucer-shaped aerobrake. Four pressurized living modules housing six explorers nestled within the saucer. Twin restartable rocket engines drew propellant from spherical liquid hydrogen and liquid oxygen tanks mounted on top of the living modules. A docking tunnel started at the conical ERV mounted on the aerobrake's inner surface, passed through a "bridge" tunnel linking the modules, and protruded beyond the twin engine bells. The thick-walled ERV doubled as the ship's radiation shelter.
The sprint vehicle would leave Earth on 21 November 2004. The first OTV would accelerate the sprint ship and second OTV, separate, and aerobrake in Earth's atmosphere for return to the Space Station. The second OTV would also accelerate the sprint ship and return to the station. The OTVs could be reused for future sprint/split Mars expeditions. The sprint vehicle would then fire its own rockets briefly to complete insertion onto a low-energy trans-Mars trajectory. A six-month trip to Mars would be possible, but Niehoff's team advocated an eight-month trajectory that would allow a Mars flyby and abort to Earth if the cargo ship waiting in Mars orbit with the piloted ship's Earth-return propellant failed during the crew's flight to Mars. An abort would have the Mars crew back on Earth on 5 January 2006. Assuming no abort became necessary, the sprint ship would aerobrake into Mars orbit on 3 July 2005. 32