The National Aeronautics and Space Administration is considering a plan to delay its 1982 Galileo mission to Jupiter and split it into two flights that would add more than $60 million to its cost.

A decision to move back the 1982 mission to 1984 could come his week, Angelo Guastaferro, director of planetary programs for NASA, said in an interview. If the decision is made to defer Galileo, Guastaferro said, then the mission would be split in two with the spacecraft to orbit Jupiter being launched 44 days ahead of a second spacecraft that would dive into the giant planet's atmosphere.

"A two-year delay means two years of inflation added to the cost," Guastaferro said. "It also means you have to develop a separate rocket and carrier for the probe instead of going piggyback on the orbiter, and that is an investment of more than $50 million."

The estimated cost of Galileo now is $285 million, exclusive of the flight cost of the shuttle that will carry Galileo into orbit and the rocket motors that will fire it from Earth orbit toward Jupiter. Clearly, the cost of a delayed mission will be at least $350 million including launch costs.

The two-year delay, if it comes, is the result of delays in developing improved versions of the space shuttle engine called the "109 percent engine" that burns at higher temperatures, delivers more thrust and can carry more weight into orbit.

The 4,600-pound Galileo, the solid rocket motors it will carry to fire it from orbit toward Jupiter and the mechanical devices that hold them strapped down inside the shuttle need the 109 percent engines to lift them into Earth orbit. Without the improved engines, Galileo is too heavy, and so much fuel would have to be taken off the spacecraft to lighten it that it could no longer navigate into orbit when it reaches Jupiter.

Two options were available to NASA to save Galileo from the indefinite delays of waiting for the 109 percent engine's development. One would be to carry a hydrogen-fueled Centaur engine in the shuttle to launch Galileo toward Jupiter, which could cost at least $100 million to make it safe so the astronauts flying the shuttle would not be in danger of a hydrogen explosion.

Guastaferro said it might take five years to develop a system that could vent Centaur's hydrogen fuel into space if the astronauts aboard the shuttle had to abort their flight for some unforeseen reason.

The easier and cheaper way to save Galileo is to delay the mission and split it in two. Delaying it to 1984 is being considered to allow the space agency to go to open bidding on the rocket and carrier spacecraft that would take the probe to Jupiter.

"If we went to a 1983 launch we'd almost have to go to a sole source company for the carrier," Guastaferro said. "Delaying to 1984 is more cost efficient becUSE we can go into more competitive bidding for the carrier."