The Reagan administration is tentatively proposing a slash of more than 9 percent in the budget of the National Aeronautics and Space Administration.
Such a cut would bring the interplanetary exploration program to a virtual halt for the rest of this decade.
The cuts are included in a wide-ranging "hit list" prepared by the Office of Management and Budget. Disclosure of the proposals took NASA's top management by surprise.
If OMB Director David Stockman prevails, NASA will lose $629 million of the $6.726 billion budget that President Carter submitted to Congress shortly before he left office.
No element of the space program -- including even the hitherto sacrosanct space shuttle manned rocketship -- would be spared OMB's axe. The new proposals call for deleting the option to build a fifth shuttle to augment the four now authorized as the mainstays of both civilian and military space activities beginning about 1985.
Also doomed under the OMB formula would be a project called Galileo, designed to continue scientific investigations of Jupiter and its ring and moon systems that began with the Pioneer and Voyager missions of the 1970s.
The cuts also would "defer" -- for fiscal 1982, at least -- an advanced program for the mapping of cloud-shrouded Venus, whose surface features were first disclosed in crude detail by a Pioneer spacecraft last May.
The de-emphasis on interplanetary exploration, if approved, would virtually eliminate the Jet Propulsion Laboratory in Pasadena, Calif., as a significant center of space research after the middle of this decade.