The Soviet Union's recent test of a new strategic missile raises important questions about the delayed SALT II treaty, and about whether SALT's delay means a heightened US-Soviet arms race.
Carter administration experts admit they are unable to read with certainty the partially encoded data from the test firing, late last month, of a new submarine-type ballistic missile from a Soviet missile testing site on land.
The US State Department has wished to avoid aggravating further the Soviet-US tensions arising from the Afghanistan situation by charging that the encoding violated SALT II's prescriptions against encrypting or otherwise "deliberately" hiding essential missile data.
"We are monitoring the situation closely," said a State Department official after disclosure of the previously classified fact that the test took place, "to assess whether there has been any violation of the terms of the SALT II treaty.
"At present, we have no basis for concluding that there has been any such violation."
The missile test failed somewhere over the northern USSR. If it had reached its target (presumably in northwestern Siberia's Kamchatka Province), the telemetry or electronic emissions, and other data on impact, would have enabled the US to determine whether the encrypting was of the "deliberate" kind that SALT II treaty forbids, administration analysts say.
Though SALT II is still delayed -- perhaps indefinitely -- in ratification by the US Senate following the Afghanistan invasion, President Carter and Defense Secretary Harold Brown have said the United States and the Soviet Union will both urgently need the treaty to cap the strategic missile race. They have said they hope it will be tacitly observed, even though unratified.
What data has become publicly known from the late-January Russian test discloses that the new Soviet missile, like US submarine-launched missiles, uses solid fuel, rather than less reliable liquid propellant used up to now in Soviet submarine-launched ballistic missiles (SLBMs).
Intelligence analysts say they believe the newest missile is intended for a new generation of nuclear-powered, missile-firing submarine called the Typhoon, a larger version of the Soviet Delta-class strategic submarine which carries 16 missiles.
It could be a multiple warhead (MIRV) follow-on to the Russian SSB-18, which has a 4,700-mile range, enabling it to hit continental US targets from such remote Soviet submarine refuges as the Sea of Okhotsk in the Arctic north. Each SSN-18 has three separate warheads.
The US has at present about 41 operational nuclear-powered missile submarines , about half of which are on station and ready to fire at any given time. Each carries 16 missiles. The Soviets operate about 90 ballistic missile submarines, including about 16 of the 1960 vintage "Golf" class diesel-powered craft carrying 180-mile-range missiles; seven "Hotel" class which are similar to Golf but nuclear powered; about 30 "Yankee" class, each with 161,800-mile-range missiles.
The SALT II agreement places no limits on development of new SLBMs or submarine-launched cruise missiles.