Last month in the New Mexico desert, the United States Air Force tried to blow up several small trucks. The vehicles resembled large, wheeled armadillos. They were models of mobile launchers for Midgetman, the small intercontinental ballistic missile now under development, and they survived a simulated 8-kiloton nuclear blast.
While the MX and Strategic Defense Initiative draw all the headlines, the Midgetman program is striding smartly ahead. It is very popular in Washington, with Democrats and Republicans alike.
But there are features of the single-warhead missile, such as the high cost of its mobility, that may yet draw it into an MX-like debate, experts say.
Midgetman (or, as the Pentagon prefers to call it, the small intercontinental ballistic missile) has been under fast development since it was recommended in an April 1983 report prepared by the President's Commission on Strategic Forces, the Scowcroft commission.
About 44 feet long, Midgetman is intended to be survivable enough so that the Soviet Union will know it cannot launch a disabling first strike on the US missile force. Survivability would be determined by how the missile is stored. It could be kept in superhard silos, or shuttled around large Western bases on hardened launchers. The US has yet to decide on such a basing mode, says Capt. Rick Lehner of the Air Force ICBM Modernization Office.
The June 27 blast test at White Sands, N.M., was an attempt to see if mobile launchers are practical. While all the data from the test have yet to be evaluated, detailed model launchers sat upright and undamaged though subjected to blast overpressures between 8 and 50 pounds per square inch (psi), says Captain Lehner. (Overpressure refers to the amount of blast-generated air pressure in excess of normal atmospheric pressure.) By contrast, an overpressure of 2 psi turns a house into rubble. The goal is to design mobile launchers to stand erect about a mile away from a 1-megaton nuclear blast.
All in all, Midgetman is moving toward scheduled deployment in 1992 extraordinarily fast for a US weapons system, notes Lehner. On July 1, for instance, the Air Force awarded contracts worth $447 million to Martin Marietta, to assemble and flight test the new missile.
For Midgetman, things have been smooth so far partly because it is as popular in Congress as a Friday with no scheduled votes. Such is the enthusiasm for the missile that it should be renamed ``Congressman,'' grumbles one congressional aide critical of the program.
Rep. Les Aspin (D) of Wisconsin, chairman of the House Armed Services Committee, is a big Midgetman fan, though he led the fight to cap MX deployment at 50. At Representative Aspin's urging, the Democratic-controlled House last month voted to add $150 million to the Pentagon's 1986 budget request for the missile.
But like a speck of cloud on the horizon, trouble may be looming in the distance.
``There may be some weaknesses to the Midgetman case that have not been thought through,'' says Rodney Jones, nuclear policy studies director at the Center for Strategic and International Studies at Georgetown University.
Cost is one thing that might yet haunt the missile. Mobile launchers and hardened silos are extremely expensive. The Air Force has not yet decided how many Midgetmen it will request, but a 500-missile force would run about $44 billion, according to a just-released General Accounting Office report.
There is also some debate over whether Midgetman can be made survivable against a Soviet attack. Without an arms control agreement limiting offensive weapons, the USSR might build enough warheads to barrage the wide-open spaces where Midgetman would lurk, destroying even the quickest and hardest of mobile launchers, critics claim.
Controlling and communicating with a mobile nuclear missile, the GAO report adds, is a technical challenge that has yet to be addressed.
And, with a congressionally mandated weight limit of 15 tons, Midgetman may be too small to carry the most advanced US guidance systems. It might not be able to carry the countermeasures, such as insulation against laser attack, that would be needed to penetrate a Soviet strategic defense system, complains Sen. Pete Wilson (R) of California, a vociferous Midgetman critic.
Antinuclear groups are already gearing up for Midgetman debate. ``A lot of our activists see it as the MX battle all over again,'' says Laurie Duker, political director of SANE.
Still, the advent of many small single-warhead missiles, scuttling around like hermit crabs or hidden deep in the earth, would be a stabilizing factor in the nuclear balance, supporters claim. Such a force, they say, would be a less tempting target to the Soviets than today's fixed-silo, multiwarhead ICBMs.
The USSR, for its part, has already begun deploying a somewhat less-sophisticated mobile missile, the SS-25.
``I'm worried Congress is going to argue Midgetman to death,'' says James Hackett, a national-security analyst at the Heritage Foundation.