A host of unresolved issues remain, from its high price and its uncertain return to its impact on the scientific community in the United States and around the world. Politics is sure to play a major role in choosing the site, including the value of support from a lame-duck administration for a project that will not be completed until 1996 at the earliest.
A major issue is the project's cost, estimated at $4.4 billion in current dollars by Energy Secretary John Herrington. Many scientists worry that it will siphon off money from smaller research projects, not just in high-energy physics but in other disciplines as well. Others see the president's endorsement, along with his earlier pledge to double the size of the National Science Foundation budget over the next five years and the growing concern about upgrading the country's technological base, as evidence of a climate that favors all types of basic research.
The proposed accelerator, 52 miles in circumference, would contain two oval rings surrounded by 10,000 superconducting magnets that will steer accelerating protons toward head-on collisions at 40 TeV. (40 trillion volts). Observing the debris from these high-energy proton collisions will allow physicists to study the fundamental constituents of matter and the forces acting between them.
Support for the project in Congress is seen as a mile wide and an inch deep. "It's easy to get political support for the SSC because so many states want the collider," said one appropriations committee staffer, who requested anonymity, about the upcoming scramble by legislators to gain for their constituents one of the largest construction projects in recent years. "One of the big questions is, 'Will that support disappear once the site has been chosen?'"
The project is expected to employ 4,500 construction workers at its peak. It will have a permanent staff of 2,500, including technical and support personnel, as well as space for 500 visiting scientists.
Spread over eight years, the construction of the SSC would roughly double the funding of high-energy physics by the Department of Energy during that time unless other facilities or research projects were shut down or deferred. Rep. Marilyn Lloyd (D-Tenn.), chairman of the House Subcommittee on Energy Research and Development, is seeking assurances that the Department will continue to fund existing programs worth a total of $2.75 billion over the next several years, according to subcommittee staff director John Dugan. But such a promise may be hard to come by.
"An assurance that funding it [the SSC] is not a tradeoff only works for short-term expenditures," said John Andelin, assistant director for the Division of Science, Information and Natural Resources at the congressionally funded Office of Technology Assessment. "We don't have any idea what the 1991 budget will be."
Although supporters cite the planned growth in the NSF as evidence that the research pot is becoming larger, the fate of such a commitment under a new administration is not clear. Furthermore, researchers say that even a doubling of the NSF budget, from $1.6 billion this year to $3.2 billion in 1992, falls far short of what is needed. Small-scale physics research itself needs $1 billion to improve instrumentation at poorly-equipped university laboratories, noted Daniel Kleppner, a physicist at MIT and a member of the National Research Council panel that issued last year's report Physics Through the 1990s.
One way to reduce the cost to the United States is to find international collaborators.
"If we can meet one-third of the costs through international contributions, the burden ought to be manageable," said William Carey, executive director of the American Association for the Advancement of Science. "Unless that kind of ratio of cost-sharing can be achieved," he said, "it is by no means clear that the SSC can go ahead without consequences to the rest of the scientific community."
High-energy physicists agree that Japan appears to be the most likely candidate for international collaboration. Toichi Sakata, first secretary at the Japanese Embassy in Washington, said informal discussions have been held between experts from both countries. Both Western Europe and the Soviet Union are committed to ongoing accelerator projects for the next several years.
It is difficult to evaluate the possible spin-offs from such a massive project. Energy officials say the SSC can be built with existing technology, much of it developed since the department began to fund supercollider R&D and design in 1983.
Spin-offs already underway from existing projects, according to physicist Peter McIntyre of Texas A&M University, include a less costly nuclear magnetic resonance (NMR) system with increased resolution using superferric NMR magnets, an electron accelerator that sterilizes insect larvae in food by bombarding it with a 2 MeV electron beam, and new techniques to build tunnels for subways and sewer projects.
McIntyre believes that construction of the collider will promote additional work in the field. "We anticipate continuing superconducting research in parallel with the SSC," he said. Advances in superconducting magnets may allow physicists to replace the original 6.4 Testa magnets with more powerful ones that can boost proton energies above 40 TeV.
One outspoken opponent of the SSC is Rustum Roy, director of the Program on Science, Technology and Society at Pennsylvania State University. Roy labels high-energy physicists the "spoiled brats of the physics community" for requesting such a costly machine, given the country's $200-billion deficit.
"I am a great supporter of science," Roy said. "But publicly funded science should be accountable to the public. This is pork barrel science."