The White House and Space Council knew that political forces outside their control were torpedoing their new, major initiative.21 To fight this effect, the Space Council convened a special committee to examine the 90-Day Study, as well as to review detailed alternatives prepared by industry and other federal entities. The most famous of the latter was the proposal from Lawrence Livermore National Laboratory to use inflatable vehicles launched on existing expendable rockets.22 This proposal claimed that both a lunar return and a manned Mars mission could be conducted for less than one-tenth the leaked cost of the 90-Day Study. Regardless of the doubtful veracity of that cost estimate, or the technical feasibility of the concept, it drew major attention from the White House. That attention propelled the canvassing of a wider segment of the community with hopes it would generate new and innovative ideas with which to implement the SEI for a fraction of the funding that NASA claimed was needed. The National Research Council, whose special report on the study concluded that a variety of other technical options should be investigated, ones that NASA had not considered, provided additional support for a major reevaluation of the 90-Day Study.
In this vein, the Space Council decided to create an outreach effort that would gather up the best technical ideas on how to implement the SEI from all sectors. These educated and innovative suggestions and plans were to be collected, evaluated, and high-graded by a special panel called the Synthesis Group and distilled into a plan for a magical—meaning cheap—beanstalk into space. This panel included members from academia, government, and industry and was chaired by astronaut Tom Stafford. I was a member of this group from August 1990 to June 1991. Tom Stafford said this activity was “like drinking from a fire hose,” and I found that to be an apt description. The ten months spent serving on Synthesis was a crash course in astronautics, a course that included the benefits and pitfalls of technology development and its role in architectural design. As one might expect, the massive input from the space community did not contain any “magic beans” or “silver bullets” that would take us to the Moon and the planets faster, better, or cheaper.23 And in that sense, the Synthesis Group did not succeed. But in another sense, the Synthesis Group advanced our understanding about the Moon and its crucial role for human expansion into the solar system.
Two events occurred in the spring and summer of 1990 that severely damaged the cause of SEI. The first event involved the Hubble Space Telescope. Although the telescope had been successfully launched, it was soon discovered that its main optical element had been ground to the wrong specification. This mistake caused Hubble’s highly anticipated new images of the universe to be out of focus.24 The other event was the temporary grounding of the shuttle fleet because of an unresolved hydrogen leak. These problems, along with the release of the 90-Day Study, combined to present the image of a space agency that was both technically incompetent and politically out of touch. Thus, despite giving the space agency an additional $2 billion overall in the FY 1991 budget, Congress zeroed out the SEI, a clear signal that NASA was in serious political trouble. The deep antipathy between the space agency and the White House was finally resolved with the sacking of Richard Truly as administrator and the subsequent hiring of Daniel Goldin as his replacement. Despite attempts to initiate SEI again in the following two years, Congress would not approve or fund it, and the initiative was terminated following the reelection defeat of President Bush and the advent of the Clinton administration.25
The Clementine Mission and Its Legacy (1994)
The lunar science community continued to lobby NASA to send a robotic orbiter to the Moon, but to no avail. Their goal was to map the Moon’s shape, composition, and other physical properties. Such a mission would not only document the processes and history of the Moon but would also serve as an operational template for the exploration of other airless planetary objects. A collection of global remote sensing data could provide scientists with invaluable ground truth when used in conjunction with the previously returned Apollo surface samples. The Lunar Polar Orbiter mission, proposed several times, never received a new start. Its last incarnation was the Jet Propulsion Laboratory’s Lunar Observer, patterned after the ill-fated Mars Observer mission. The cost review of Lunar Observer came in at around $1 billion in 1990 dollars. Of course, it was passed over yet again.
Stewart “Stu” Nozette of Lawrence Livermore National Laboratory, another Synthesis Group member, was involved in the Brilliant Pebbles (BP) program of the Defense Department’s Strategic Defense Initiative.26 The idea behind BP was to defend the nation against ballistic missiles by launching swarms of small, inexpensive satellites, each capable of observing, calculating and plotting an intercept course to incoming missiles (the “brilliant”) and then rendering them inoperative by collision (the “pebble”). These small, three-axis stabilized vehicles carried imaging sensors (both active and passive) as well as in-flight computers and propulsion systems. In short, they were small but fully capable, self-contained spacecraft.
Nozette’s idea was to fly a BP to a distant target in space. Because of his interest in space resources, he devised a mission that would fly by an asteroid and possibly orbit the Moon. Stu and I discussed these possibilities, and it seemed that a fairly significant mission might be built around these small spacecraft. My colleague Eugene Shoemaker of the US Geological Survey was brought in early on the planning of this mission. Gene was a legend in planetary science circles. A member of the National Academy of Sciences, he had done the original geological mapping of the Moon before the Apollo program and was actively researching asteroids. His interest and involvement with the mission brought both prestige and credibility to the idea.
An agreement between NASA and the Strategic Defense Initiative Organization (SDIO) specified that NASA would provide the science team and the communications tracking support for the flight, and that SDIO would provide the sensors, spacecraft, and launch. The sensors had been developed at Livermore as part of the BP program, while the Naval Research Laboratory (NRL) would design and build the spacecraft, later named Clementine. Launch was on a surplus Air Force Titan II rocket, the same vehicle NASA used to launch the two-man Gemini missions in the 1960s. Because the Titan II pad at the Cape had been dismantled, the mission would be launched from Vandenberg Air Force Base near Lompoc, California.
The mission would put Clementine in a polar orbit around the Moon for two months, providing global coverage. The spacecraft would map the color of the lunar surface in eleven wavelengths in the ultraviolet, visible, and near-infrared portions of the spectrum and measure the Moon’s shape from laser ranging. Other remote measurements would be acquired as opportunity presented. After this phase, Clementine was to leave lunar orbit and fly by the near-Earth asteroid Geographos. Program Manager Pedro Rustan, an Air Force colonel, was a skilled, tough engineer who kept us to deadlines. Stu became his deputy, coordinating many different activities, ranging from science objectives to spacecraft fabrication and testing. The Science Team, twelve lunar scientists with varied expertise, was selected from individual proposals submitted to NASA. Gene Shoemaker was named the team leader, and I was his deputy. Together, we planned mission operations with the NRL and Livermore teams. The Science Team carefully selected the filter bandpasses for the imaging systems that would allow the identification of lunar rock types from the color images.
The Clementine mission was remarkable for its short development cycle and cost. Twenty-two months elapsed from project start to launch, while a typical NASA planetary mission took from three to four years. In FY 1992 dollars, NRL spent about $60 million for the spacecraft and the mission control center. Livermore spent about $40 million on support services and on the production of the mission sensors. The Titan II launch vehicle and services, supplied by the Air Force, were valued at about $20 million, with an additional $10 million or so for avionics upgrades. The NASA Science Team cost a couple of million dollars, and the Deep Space Network support was a few million more. By totaling those numbers, I
estimate that the mission cost about $140 million, or $540 million in today’s dollars; for comparison, the then-recently lost NASA JPL Mars Observer mission cost a bit over $800 million, or more than $2 billion in 2014 dollars.
Those cost numbers caused considerable controversy, with some in the scientific community whining that the massive “Star Wars” (SDI) program absorbed and hid much of Clementine’s cost. In fact, the whole point of the Brilliant Pebbles program was to adapt cheap, rugged tactical sensors to deep space use and thus take advantage of the cost savings provided by mass production (as opposed to the custom builds of most space systems). Moreover, there was nothing to stop NASA from using this same technology, other than a not-invented-here mindset and the still-prevalent tendency in the space science community to gold-plate scientific payloads.
The Clementine mission demonstrated the value of the so-called Faster–Better–Cheaper (FBC) paradigm.27 The concept is not that cheap missions are inherently “better” but that by carefully restricting mission objectives to only the most essential information, it is possible to fly smaller capable missions that can return 80 to 90 percent of the most critical data; resources are often squandered in an attempt to achieve that last 10 percent of performance. Maybe FBC should be renamed Faster–Cheaper–Good Enough. The broad success of NASA’s Discovery program over the last twenty years, in which mission objectives are carefully defined and limited to control overall cost, is testament enough to the general validity of the FBC concept. In addition to its scientific return, the Clementine mission flight-tested and qualified twenty-two new spacecraft technologies, including solid-state data recorders, nickel-hydrogen batteries, lightweight components, and low-mass, low-shock, nonexplosive release devices. All of these technologies have been employed on dozens of subsequent space missions, making many of these spacecraft lighter, more reliable, and longer-lived.
On the morning of January 25, 1994, less than two years after project start, the members of Clementine’s science team stood together on a cold, windy California beach just a couple of miles from SLC-4W. We watched as the Clementine Titan II rose above the launch pad on a cloud of orange smoke and flame, arching into the clear, blue Pacific sky. We followed the vehicle’s progress all the way through staging before losing sight of it. I left Vandenberg excited about the mission ahead, but my mood quickly changed when Science Operations Manager Trevor Sorensen sent news that we were in danger of losing the spacecraft (erroneous commands had been sent to Clementine, and the spacecraft was out of control). Fortunately, we recovered.
Once our spacecraft had safely inserted itself into orbit around the Moon and began mapping its surface, we were eager to get our first images. Our perch for receiving this mission data was a converted National Guard armory in Alexandria, Virginia. Dubbed the Batcave, the armory served as mission control center for the duration of the mission. Designed to save fuel, Clementine had taken a month-long, leisurely looping trip to the Moon, arriving there on February 19. When the first image finally flashed on the screen, I immediately recognized the crater but due to all the excitement, initially drew a blank on its name. Quickly consulting the wall map, I saw that we were looking at Nansen, a crater located near the north pole. A very strong sense of physically being present at the Moon came over me—I was flying across a landscape as familiar to me as any one that I knew on the Earth.
Mission operations became a regular series of work cycles arranged around the routine of collecting and downlinking data, verifying that the data was good, and making some initial scientific observations, although a couple of incidents from my time in the Batcave stand out.
As Clementine’s orbit was about to pass over Tycho, the largest rayed crater on the near side of the Moon, I alerted everyone in the Batcave’s control room that something incredible was about to appear. Audible gasps greeted the spectacular images of the floor and central peak of Tycho that came into view. On another occasion, Dave Smith, a science team member from NASA–Goddard Space Flight Center, asked how much polar flattening might be expected for the Moon. I replied “almost none,” mainly because of the slow rotation rate of the Moon (once every 708 hours) combined with the rigid, nonplastic state of the lunar globe. Then, as the orbital ground tracks slowly marched westward across the far side of the Moon, we saw an astonishing falling off of topography toward the south pole. This large negative relief was the rim and floor of the South Pole–Aitken (SPA) basin, an impact crater more than 2,600 kilometers across and more than 12 kilometers deep. Geologists had long known that this basin was present, but until Clementine mapped its topography, no one had fully appreciated its huge size and state of preservation.
By now, Clementine had already shown us the nature of the polar regions of the Moon, including peaks of near permanent sun-illumination and crater interiors in permanent darkness. From his first look at the poles, Gene Shoemaker had an inkling that something interesting was going on. Gene tried to convince me that water ice might be present there, an idea about which I had always been skeptical. At that time, no trace of hydration had ever been found in lunar minerals, and the prevailing wisdom was that the Moon had always been bone-dry. With Gene arguing for us to keep an open mind and Deputy Program Manager Stu Nozette devising a bistatic radio frequency (RF) experiment to use the spacecraft transmitter to “peek” into the dark areas of the poles, we moved ahead on planning our observations. This turned out to be the setup for a history-making event midway through the orbital mapping campaign.
Although Clementine did not carry sensors for the detection of water, Stu believed we could improvise an experiment using the spacecraft’s radio transmitter to “look into” the dark (and thus very cold) areas near the poles, places where water ice might exist. Radio echoes from the Moon could be detected on the giant radio antenna dish at Goldstone in California’s Mojave Desert. With careful planning and commanding of the spacecraft by Radio Engineer Chris Lichtenberg, we successfully took bistatic radio frequency (RF) data of both poles during those phasing orbits, when Clementine shifted the perilune (low point) of its polar orbit from 30° south to 30° north latitude.
To my astonishment, a single pass over the dark areas of the south pole of the Moon showed evidence for enhanced circular polarization ratio (CPR), a possible indicator of the presence of ice. A control orbit over a nearby sunlit area showed no such evidence. However, CPR is not a unique determinant for ice, as rocky, rough surfaces and ice deposits both show high CPR. It took a couple of years for us to reduce and fully understand the data, but the bistatic experiment was successful—and a huge scientific bonus. In part, our ice interpretation was supported by the then-recent discovery of water ice at the poles of Mercury (a planet very similar to the Moon with a comparable polar environment).28 Our published results in a December 1996 issue of Science magazine set off a media frenzy, followed by a decade of scientific argument and counterargument about the interpretation of radar data for the lunar poles—an argument that continues to a lesser degree to this day, despite subsequent confirmation of lunar polar water from several other detection techniques.29
The Batcave played host to several distinguished visitors during the two months that Clementine orbited the Moon, most notably astronauts John Young, a familiar face to members of the Synthesis Group and always a friend of lunar science, and Wubbo Ockels, a Dutch physicist with the European Space Agency. Ockels, encouraged by Clementine’s success, campaigned to generate enthusiasm for small, cheap lunar missions at ESTEC, the European space center in the Netherlands where he worked. US Representatives Bob Zimmer and Jim Moran were impressed with our operation and pledged their support in Congress for future space efforts like Clementine. Finally, then-new Administrator of NASA Dan Goldin visited, distributing lapel pins and offering encouragement to the worker bees. Not all at NASA were enamored with the mission though, with some resenting the attention it had drawn, particularly with regard to the inevitable comparisons with their own ongoing and budget overrunning robotic missions.
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With Clementine, we had successfully returned to the Moon, mapped it globally, and made several significant discoveries. A Science Team press conference was scheduled at NASA Headquarters to report on the new scientific findings, but NASA intervened at the last minute and cancelled our briefing. Several mutually exclusive excuses were given for this cancellation, but it was clear to members of the science team that some in the agency wanted to keep a lid on the scientific success of the mission, which was embarrassing to NASA because Clementine was much cheaper than similar agency efforts, yet just as scientifically productive, if not more so. But in time, news of the discovery of “the most valuable piece of real estate in the solar system” was revealed. With urging from the planetary science community, NASA agreed to fund a research program to take advantage of the abundant new lunar data acquired by Clementine.
Two cameras on Clementine with eleven filters covered the spectral range of 415 to 1900 nm, where absorption bands of the major lunar rock-forming minerals (plagioclase, pyroxene and olivine) are found. Varying proportions of these minerals make up the suite of lunar rocks. Global color maps made from these spectral images show the distribution of rock types on the Moon. The uppermost lunar crust is a mixed zone, whose composition varies widely with location. Below this zone is a layer of nearly pure anorthosite, a rock type made up solely of plagioclase feldspar—the original lunar crust, formed during the global “magma ocean” melting event. Craters and large basins act as natural “drill holes” in the crust, exposing deeper levels of the Moon. The deepest parts of the interior (and possibly the upper mantle) are exposed at the surface within the floor of the enormous (2,600 km diameter) South Pole–Aitken basin on the far side of the Moon.
The Value of the Moon Page 7
