|Artist concept of Space Clipper Alpha c. 1985. Image credit: NASA|
At the same time, Humphrey announced that the United States would "taper off" manned spaceflight by 1975. Questioned further, he called for a "prudent reduction in spaceflight expenditure" during his second term in office.
Apollo spacecraft visited the Moon three more times after Humphrey's announcement. The Apollo 16 Lunar Module (LM) Orion landed in the lunar highlands near the crater Lade in May 1972. The Apollo 17 Command and Service Module Endurance, with a crew of two, reached lunar polar orbit after a three-day trip from Earth, mapped the entire Moon at high resolution for 28 days, and returned to Earth in three days (December 1972-January 1973). Total mission duration was thus 34 days, a new (though short-lived) endurance record. The Apollo 18 LM Discovery landed among the Marius Hills (July 1975).
Between Apollo 17 and Apollo 18, NASA launched 85-ton Skylab A into Earth orbit on a two-stage Saturn V rocket (May 1973). The station, a converted Saturn V S-IVB third stage originally intended for the cancelled Apollo 20 lunar mission, received three three-man crews: the Skylab 1 crew repaired the station, which was damaged during launch, then lived on board for 29 days in June-July 1973; the Skylab 2 crew occupied Skylab A for 56 days in September-October 1973; then the Skylab 3 crew set a new endurance record of 85 days starting in December 1973. Skylab A's Apollo Telescope Mount (ATM) was designed to observe the Sun.
Skylab B - originally the Apollo 19 S-IVB stage - reached orbit in May 1974 and received two crews: the Skylab 4 crew lived on board for 119 days starting in June 1974, setting a spaceflight endurance record which stands today. The Skylab 5 crew closed out the program with a 58-day stay in January-March 1975. Skylab B's "stellar ATM" looked to distant stars and galaxies.
The end of U.S. manned spaceflight and NASA's shift back to aviation research - its prime focus during the four decades (1915-1958) when it was a collection of laboratories governed by the National Advisory Council on Aeronautics (NACA) - meant major changes across the agency. By virtue of its long association with aeronautics development (and, of course, its California location), former NACA lab Ames Research Center (ARC) became the prime center for Humphrey's supersonic development program. From the early 1970s to the early 1980s, ARC worked mainly with California-based contractors and flew test vehicles exclusively out of Dryden Flight Research Center near Los Angeles.
Robotic space exploration assumed a new importance for NASA. The Jet Propulsion Laboratory (JPL) in Pasadena, California, operated on contract to NASA by the California Institute of Technology, focused on planetary flyby and orbiter missions. JPL's four-spacecraft Grand Tour series explored Jupiter, Saturn, Uranus, Neptune, and Pluto in the 1980s and 1990s.
The Manned Spacecraft Center (MSC) in Houston was, of course, hit hard by the turn away from piloted spaceflight; it shed more than two-thirds of its contractors and half of its civil servants by 1977. Marshall Space Flight Center (MSFC) in Huntsville, Alabama, also hard-hit, proved more adaptable; under its second director, Wernher von Braun's long-time colleague Ernst Stuhlinger, it became NASA's lead center for space solar power and electric propulsion research. In 1978, NASA Headquarters made MSFC prime center for development of the Comet Halley rendezvous mission, which would employ solar-electric propulsion. NASA Lewis Research Center (LeRC) in Cleveland, Ohio, another former NACA lab, found roles in lightweight aircraft structures and nuclear power source development for robotic planetary missions.
NASA Langley Research Center in Hampton, Virginia, another old NACA facility, managed the three Viking Mars missions. JPL was its contractor responsible for the Viking Mars Orbiters, and Martin Marietta-Denver built the twin Viking 1975 landers and the Viking 1979 lander/rover. MSFC, which had managed the Apollo Lunar Roving Vehicle contract, assisted LaRC with the Viking lander/rover's mobility system.
NASA Goddard Space Flight Center (GSFC) in suburban Washington, DC, focused on Earth-orbiting science satellites in partnership with the Johns Hopkins University Applied Physics Laboratory in Baltimore. GSFC assisted MSFC with the Comet Halley mission in the area of instrument development, and worked with the Electronics Research Center (ERC) in Boston, which partnered with the Massachusetts Institute of Technology (MIT), to develop remotely operated Earth-orbital repair and assembly robotics. GSFC also emphasized astronomy satellites.
Beginning in the early 1980s, supersonic research gradually expanded into the hypersonic realm (that is, to speeds faster than five times the speed of sound) and above the Karman Line (the boundary between air and space at 330,000 feet - 62 miles - above sea level). Without really meaning to, NASA once again traveled into space; and, in 1983, President Nelson Rockefeller awarded astronaut wings to 31 test-pilots in a White House ceremony.
The following year, Rockefeller called for a piloted "high-hypersonic" aircraft capable of reaching Earth orbit. He named the development program Project Space Clipper and gave NASA until 1990 to accomplish the task. Many in the aerospace industry greeted Rockefeller's speech with derision; they confidently predicted that a reusable single-stage-to-orbit aircraft was at least a decade away, and might not be possible at all.
President Lloyd Bentsen, a native of Texas, supported Project Space Clipper because it enabled him to reinvigorate NASA space centers in Texas and Florida. MSC experienced a partial rebound as a lunar science institute and crew escape system and crew equipment design center. Kennedy Space Center (KSC), meanwhile, rebounded as the "East Coast Dryden."
On 23 January 1990, Space Clipper Alpha carried out Hypersonic Orbital Test (HOT) 1, the first U.S. piloted Earth-orbital space mission since Skylab 5. Using a "trimodal engine," Alpha flew from a KSC runway to low-Earth orbit, orbited three times, reentered over the Pacific, and flew at low hypersonic speed to a landing on the same runway it had departed six hours earlier. A test-bed for hypersonic experimentation with room for only two crew, Alpha flew to orbit six more times (HOT missions 2a, 2b, 3, 4, 5a, and 5b) before its retirement in late 1993. By then, two operational Space Clippers were undergoing integration and ground testing at Dryden.
Critics argued that Space Clipper was a sophisticated spacecraft with no mission. A 1989 MIT study (the Minsky Study) conducted for new President Jack Kemp had, however, already identified a crew-tended/semi-automated space station as a logical next step for NASA. In January 1992, at the start of both his reelection campaign and the International Space Year, Kemp called for just such a station.
Roadblocks soon appeared, however. Space Clipper, with a mass at takeoff of 110 tons, had a maximum payload mass of just six tons, so could not economically launch the new station. In addition, NASA had pared down its stable of expendable rockets so that its most capable - the Titan III - could place only about 14 tons into low-Earth orbit. This was adequate for robotic Earth-orbital and planetary missions, which had been shrinking in mass since the mid-1980s, but was judged insufficient for launching a crew-tended Earth-orbiting space laboratory.
The Soviet Civil War of 1993-1995 also intervened. Following the Alma Ata Incident, President Kemp grounded all planned NASA launches lest they be misinterpreted by the warring sides. Most of his second term focused on containing the conflict in Eurasia, which saw at least ten nuclear weapons exploded in anger within former Soviet territory.
During the stand-down, MIT continued research into the space laboratory mass problem. A 1994 MIT study found that a 14-ton space laboratory could be launched without science apparatus atop a Titan III and outfitted in orbit using the Space Clippers and automated systems.
Spacelab 1 reached Earth orbit in 1999. The twin Space Clippers each visited Spacelab 1 twice per year to outfit the small station; then, after outfitting was completed in 2001, to resupply and change out experimental apparatus, retrieve experiment results, and service and upgrade on-board automation systems. Crew visits to the station lasted no longer than 10 days. Spacelab 2 replaced Spacelab 1 in 2006 and operated until 2014.
The 1994 MIT report also pointed to space tourism's potential. In late January 2003, a coalition of long-established aerospace companies led by Pan American Airlines launched the first commercial Space Clipper, Space Clipper-C, with six passengers on board. Pan Am selected them from a pool of more than a million applicants. They orbited Earth for two days, reveling in the sights and sensations of space travel (which, it must be admitted, included a fair amount of vomiting and some toilet accidents).
Though derided as a stunt, the Space Clipper-C flight led to dramatic changes for NASA, for it demonstrated that the U.S. citizenry had again become interested in piloted spaceflight. In January 2004, President Al Gore cited the commercial flight when he called on the aerospace agency to develop larger, more capable hypersonic orbital vehicles, upgraded expendable boosters, a permanently staffed space station, and a versatile tug that could be upgraded to land on the Moon bearing a crew. Gore also called for corporate-government partnerships, with government accepting development costs and initial risk and corporations seeking to prove that robust piloted spaceflight could pay its operating costs.
The development risk associated with all three new systems was substantial, and concern mounted as the three-pronged piloted program threatened to divert funding from widely supported NASA projects, such as the Vera Rubin Space Telescope. The program received a much-needed shot in the arm in June 2007, when the Chinese-Siberian Alliance launched and recovered a hypersonic orbital vehicle, its first piloted spacecraft. A new space race developed as the European Confederation in partnership with Japan and the Central Asian Coalition in partnership with Ukraine and India launched piloted hypersonic vehicles to Earth orbit in 2009 and 2013, respectively.
The 245-ton Space Clipper Mark II, with a payload capacity of 16 tons, debuted in 2010. Space Clipper II's design drew upon ultra-lightweight heat-resistant materials manufactured on board Spacelabs 1 and 2. President Lincoln Chafee declared the three-vehicle Space Clipper II fleet operational in 2012.
The following year, a Titan IV booster with a Mark I Space Tug upper stage placed a 45-ton core space station into low-Earth orbit. The station, the fifth launched by the United States after Skylab A and B and Spacelab 1 and 2, was subsequently named Space Station 5. Like the two Skylabs, the new station was capable of supporting long-term habitation as soon as it reached orbit. NASA has gradually expanded the station using Titan IV-launched 20-ton modules based on the Spacelab design maneuvered into place using automated Mark I Space Tugs.
Whether spaceflight can pay its operations costs remains uncertain. Some aerospace observers have argued that Space Clipper II is simply too large to pay for itself, while others counsel patience. Some - in fact, a growing number - argue that spaceflight is, after all, very young and is potentially important enough to operate indefinitely at a loss.
NASA continues Space Tug development. This year, in time for the 50th anniversary of the first manned mission to reach lunar orbit (Apollo 8, December 1968), the aerospace agency plans to launch a reusable dual Mark II Space Tug stack from Space Station 5. It will carry three astronauts around the Moon on a free-return trajectory and, after a high-speed aerobraking pass through Earth's upper atmosphere made feasible by nearly 40 years of hypersonic research and development, return them to the station. Nine Space Clipper II flights will launch the Tug components and propellants to Station 5 for automated assembly.
Though funding is tight, in 2015 President Janet Napolitano called on NASA to land humans on the Moon in 2025 for the first time since Apollo 18. China, Europe, Central Asia, and their partners have subsequently announced similar plans, though none has offered a timetable.
There can be no doubt that President Humphrey thought only of short-term political gain in 1972 when he called on NASA to shift its focus to supersonic development. Nevertheless, as can be seen, his decision had important, far-reaching implications.
As I write these words in 2018, passengers can fly around the world non-stop in less than nine hours. No major airport in the contiguous U.S. is more than an hour from any other. Monthly flights depart for tourism accommodations on board Space Station 5 (passenger numbers have, however, fallen off as the novelty of becoming motion-sick in low-Earth orbit has faded).
Soon the Moon will be within reach of astronauts for the first time in 50 years. There is already talk of a crew-tended base at one of the lunar poles, where Apollo 17 detected abundant ice in permanently shadowed craters. As NASA and its commercial partners experiment with Moonships and spaceflight cost reduction, one may be cautiously optimistic about our future off the Earth.
A Note on the Presidents
In this alternate history timeline, which I call "Our Better Angels," Nixon is outed in 1968 for his behind-the-scenes negotiations with South Vietnam to extend the Vietnam War. As a result, he is never elected, Watergate never takes place, and the Republican Party continues on a moderate course. I cite as inspiration Gregory Benford's classic novel TIMESCAPE.
1969-1977 - Hubert H. Humphrey, Democrat
1977-1981 - Edmund Muskie, Democrat
1981-1985 - Nelson Rockefeller, Republican
1985-1989 - Lloyd Bentsen, Democrat
1989-1997 - Jack Kemp, Republican
1997-2005 - Albert Gore, Democrat
2005-2013 - Lincoln Chafee, Republican
2013-present - Janet Napolitano, Democrat