|Image credit: Department of Defense|
"Let me share with you a vision of the future," Reagan began. He then summed up his vision in a two-part question replete with the Cold War language of his Presidency: "What if free people could live secure in the knowledge that their security did not rest upon the threat of instant U.S. retaliation to deter a Soviet attack, that we could intercept and destroy strategic ballistic missiles before they reached our own soil or that of our allies?"
Reagan acknowledged that his vision represented "a formidable technical task, one that may not be accomplished before the end of this century." He then called on U.S. scientists – "those who gave us nuclear weapons" – to direct their talents "to the cause of Mankind and world peace, to give us the means of rendering these nuclear weapons impotent and obsolete."
|President Ronald Reagan shares his missile-defense vision with the American people. The image on the easel is a declassified satellite view of Soviet MiG aircraft stationed in Cuba. Image credit: The Reagan Library|
The Reagan White House appointed James Fletcher, NASA Administrator from 1972 until 1977 under Presidents Nixon and Ford, to head up a panel to propose an SDI experimentation and development program. Fletcher tasked the California Space Institute (Calspace) at the University of California-San Diego (UCSD) with holding a workshop to consider whether exploiting the resources of the moon and asteroids might help to give substance to Reagan's vision. The Defense Applications of Near-Earth Resources Workshop took place in La Jolla, California, on 15-17 August 1983.
That Fletcher should have asked Calspace to assist with his SDI report is not too surprising. In February 1977, James Arnold, a UCSD chemistry professor, had spoken with NASA Administrator Fletcher about making the exploitation of near-Earth space resources a major new focus for NASA. He subsequently summed up his thoughts in a detailed two-page letter to Fletcher. Three years later, Arnold became the first director of Calspace, which had its origins in California Governor Jerry Brown's enthusiasm for technological development in his state.
Arnold's deputy in 1983-1984, young planetary scientist Stewart Nozette, organized the La Jolla workshop, which brought together 36 prominent scientists and engineers from aerospace companies, national laboratories, NASA centers, the Department of Defense, and defense think-tanks to weigh in on the potential use of moon and asteroid resources in SDI. Nozette also edited the workshop report, which Arnold submitted to Fletcher on 18 August 1983. A revised version of the workshop report was completed on 31 October 1983. This post is based upon the latter version.
In the cover letter to the La Jolla workshop report, Nozette described how, in the late 1970s, NASA, aerospace companies, and universities expended a great deal of time and effort on planning large structures - for example, Solar Power Satellites - which would be assembled in space. Some of these plans relied on space resources. Nozette explained that these studies, though conducted "in an unfocused and low priority vein," had laid the groundwork for SDI exploitation of moon and asteroid resources. The La Jolla workshop was, he added, the first to consider the defense implications of the 1970s concepts.
|Lunar prospector: Apollo 16 astronaut Charles Duke collects geologic samples in the Descartes region of the Lunar Highlands in April 1972. The Lunar Roving Vehicle is just visible among rocks and boulders in the background. Image credit: NASA|
Scientists had hypothesized since 1961 that permanently shadowed craters at the lunar poles might contain ice deposited by comet impacts. The lunar poles, far from the "Apollo Zone" – the near-equatorial region where orbital mechanics dictated the Apollo Lunar Modules could land – nevertheless remained unexplored.
In 1983, only 75 near-Earth asteroids (NEAs) had known orbital paths; the rate of discovery in the late 1970s/early 1980s suggested a population of sizable NEAs numbering many thousands, of which perhaps 20% would be readily accessible to prospecting spacecraft (these early gross estimates have been revised downward over the years). Meteorites collected on Earth were assumed (correctly) to have originated among the NEAs, but their relationship to specific asteroids remained unclear.
The La Jolla workshop report thus urged more resource exploration as an early step toward exploitation of near-Earth resources. An automated prospecting spacecraft that would pass over both lunar poles during each orbit - a Lunar Polar Orbiter (LPO) - topped the Workshop's list of "projects to be started immediately." The moon would revolve under such a spacecraft so that over the course of about two weeks it would present its entire surface to the LPO's instruments for scrutiny.
In addition, the La Jolla workshop report recommended that efforts to discover and perform initial analyses of NEAs using Earth-based telescopes should be stepped up dramatically. It noted that, in terms of NEAs accessible to spacecraft, "the most promising targets very likely have not, as yet, been detected." The workshop report then urged NASA to carry out a series of automated NEA rendezvous missions.
In 1983, NASA's piloted spaceflight focus was on working the bugs out of the Space Shuttle, which, despite a minimal flight record (the eighth Shuttle mission flew between the La Jolla workshop and completion of the Fletcher Report), already had an extensive manifest of planned missions. Many within the space community hoped that President Reagan would soon green-light a NASA Space Station that would be launched in pieces in the payload bays of Shuttle Orbiters and assembled in low-Earth orbit (LEO). They expected that auxiliary spacecraft, including piloted Orbital Transfer Vehicles (OTVs) for reaching beyond Shuttle/Station orbit, would be based permanently at the Station.
Participants in the La Jolla workshop proposed more than a dozen SDI applications for lunar and asteroid resources. What follows is a description of the top three applications in terms of the mass of lunar and asteroid materials required.
Much of the wide-ranging prospecting, mining, and processing the La Jolla workshop advocated would lead to in-space manufacture of spacecraft "armor" made of lunar aluminum, asteroid iron, and aluminum and iron alloys created by adding small amounts of metals launched from Earth. The workshop report noted that military space systems launched from Earth tended to be made as lightweight as possible to reduce launch costs; this made them fragile and thus vulnerable if attacked.
"On the other hand," the workshop report continued, "if a relatively inexpensive (500-1000 dollars per kilogram) supply of construction materials became available high above Earth, defensive systems would likely be designed very differently, with greater capabilities and greater survivability." Layered armor for an SDI missile-defense platform with a cross-sectional area of 20 square meters would have a mass of about 400 metric tons; 100 such platforms would thus require about 40,000 metric tons of armor.
Layered metal armor would blunt attacks by kinetic-energy weapons (that is, weapon systems that fired solid projectiles); for defense against particle beams or nuclear explosions, however, radiation shielding would be needed. The La Jolla workshop proposed using water from asteroids or (if any existed) from the lunar poles as neutron shielding for vulnerable electronic systems. Water would, of course, also have life support uses, and could be split into liquid oxygen and liquid hydrogen chemical rocket propellants.
After armor, the most important application of space resources in terms of mass was what the La Jolla workshop report dubbed "stabilizing inertia.” An enemy attack might cause a missile-defense platform to spin out of control even if its armor shielded it from damage. Mounting the platform on a chunk of raw asteroid would greatly increase its mass, making it much harder to shove around.
Third after armor and stabilizing inertia were heat sinks. The La Jolla workshop anticipated that missile-defense systems - for example, missile-destroying lasers powered by exploding nuclear bombs - would generate a great deal of waste heat very rapidly. Without places for the heat to go, they could easily destroy themselves. A heat sink might take the form of a large tank of water or large block of metal.
The Fletcher Panel submitted its hefty seven-volume final report to the Reagan White House on 4 November 1983. More than three decades later, most of the Fletcher Report remains classified, so the degree to which the La Jolla workshop influenced its findings is unclear.
Fifteen years into the 21st century, SDI has yet to match Reagan's vision, in no small part part because the Soviet Union - which Reagan had dubbed "the evil empire" - collapsed in 1991. Instead of leading to a shield against massive Soviet nuclear attack, SDI became the most important space technology development program since Apollo. Neither the ongoing Discovery Program of cheap, relatively frequent automated lunar and planetary missions nor the low-cost automated Mars missions of the 1996-2008 period would have been possible without the technology infusion from SDI.
|Image credit: NASA/USGS|
The Clementine spacecraft entered lunar polar orbit on 19 February 1994, where it carried out the first U.S. lunar exploration mission since Apollo 17 in December 1972. It surveyed almost the entire lunar surface for two months. In collaboration with Deep Space Network antennas on Earth, it prospected for ice in the permanently shadowed lunar polar craters. Clementine researchers interpreted data they collected as evidence of large deposits of water ice. This interpretation was questioned almost as soon as it was announced at a Department of Defense press conference on 4 December 1996. Subsequent lunar spacecraft (Lunar Prospector, Chandrayaan-1, LCROSS, and the currently operational Lunar Reconnaissance Orbiter) have, however, confirmed the existence of hundreds of millions of tons of water ice at the lunar poles.
|Permanently shadowed areas at the moon's south pole stand out as a cluster of dark gray voids at the center of this Clementine image mosaic. Image credit: NASA/USGS|
Unfortunately, just two days into its four-month journey, the spacecraft suffered a computer malfunction that caused it to expend all of its attitude-control propellant. The flyby, incidentally, had been the mission's primary goal when spacecraft and mission design began in March 1992; Clementine had been named in reference to the song "Oh, My Darling Clementine" because it would be "lost and gone forever" after it flew past Geographos. The lunar phase of the Clementine mission was added later.
A Clementine 2 asteroid-flyby spacecraft was proposed and studied, but did not receive development funding. Clementine 2 would have flown past near-Earth asteroids 433 Eros and 4179 Toutatis. During the flybys, it would have released impactors, the design of which would have been based on proposed missile interceptors. Instruments on board Clementine 2 based on missile-detection sensors would have recorded the impacts to enable scientists to determine asteroid surface properties. Work on Clementine 2 ceased in 1997.
The fate of Stewart Nozette forms a strange denouement to this story. He was widely celebrated for his work on Clementine: among other awards, he received the NASA Exceptional Achievement Medal. He went on to play roles in the Lunar Reconnaissance Orbiter and Chandrayaan-1 missions. In 2006, 49-year-old Nozette left government service to head up the not-for-profit Alliance for Competitive Technology, which received NASA funding.
Nozette, who had "top secret" security clearance from 1989 to 2006, soon came under Justice Department scrutiny for misappropriation of NASA funds and tax evasion; he was then charged with espionage after attempting to sell classified information to an FBI agent posing as an Israeli spy. In 2011, he was sentenced to 13 years in Federal prison.
"Ex-White House Scientist Pleads Guilty in Spy Case Tied to Israel," S. Shane, The New York Times, 8 September 2011, p. A22
"The Clementine Satellite," Energy & Technology Review, Lawrence Livermore National Laboratory, June 1994
"Reagan is Urged to Increase Research on Exotic Defenses Against Missiles," C. Mohr, The New York Times, 5 November 1983, p. A32
Defense Applications of Near-Earth Resources, Workshop Held at the University of California, San Diego, Hosted by the California Space Institute, 15-17 August 1983, S. Nozette, editor/workshop organizer, 31 October 1983
Address to the Nation on Defense and National Security, President Ronald Reagan, 23 March 1983
Earth-Approaching Asteroids as Targets for Exploration (1978)
An Apollo Landing Near the Great Ray Crater Tycho (1968)
Starfish and Apollo (1962)