The space agency has been told to cut so much money from its budgets for the next three years that it is considering a plan to abandon the Voyager spacecraft, now on its way from Saturn to a 1986 flight past the planet Uranus and a 1989 flyby of Neptune.

The plan is the most drastic aspect of a response being drawn up by the National Aeronautics and Space Administration to an order by the Office of Management and Budget that it cut $367 million from the fiscal 1982 budget, $1 billion from the fiscal 1983 budget and $1 billion from the fiscal 1984 budget. NASA is studying its options and has not yet submitted its plan to OMB.

One plan being discussed is to turn off the Voyager spacecraft now heading toward Uranus, the seventh planet from the sun and one never visited by an unmanned spacecraft from Earth. Turning off Voyager and silencing its radios would save the space agency $222 million in the next eight years, the amount required to keep Voyager scientists and engineers on the job and to operate the Deep Space Network of antennas in California, Spain and Australia to communicate with Voyager on its flight to Uranus and Neptune.

NASA has not yet agreed to abandon Voyager, but because it cannot afford to take money from the space shuttle's budget, it must make the cuts in its other big money programs--its planetary missions.

The space agency has decided against a mission to Halley's Comet and must now wrestle with three other large programs, the Galileo mission in 1987 to Jupiter, the Large Space Telescope to be put into earth orbit in 1985 and the Voyager missions to Uranus and Neptune. The space telescope is understood to be untouchable, in part because $300 million has already been spent on it and in part because the nation's space scientists think it is the most valuable of the missions left.

That leaves Galileo and Voyager, which if killed now would save the space agency about $520 million.

Sources said the only other way to save large amounts of money at NASA would be to delay indefinitely construction of the fourth space shuttle, called Discovery and due for delivery in 1985. Discovery is estimated to cost $1.2 billion to construct, and no decision has been made on its fate.