Lockheed Martin Corp. made an unannounced, last-minute lobbying push yesterday for legislation permitting it to complete the acquisition of Comsat Corp., as Congress prepared to adjourn for the year, according to industry and Capitol Hill sources.

The nation's leading defense contractor failed to get congressional leaders' backing for its bid, which would have required the inclusion of a special amendment to the final spending bill being drafted in Congress yesterday, congressional sources said.

Instead, the issue will be taken up early next year.

"Lockheed went to the House leadership [to] get them to tag some sentences onto the appropriations bill" to permit the Comsat acquisition, said Henry Goldberg, regulatory counsel for PanAmSat Corp., the Hughes Electronic Corp. unit that is Comsat's arch competitor.

Lockheed Chairman Vance D. Coffman met yesterday with Senate Majority Leader Trent Lott (R-Miss.) to seek support for the bid but did not succeed, an aide to Lott said.

Lockheed spokesman Charles "Chip" Manor would not comment on the reports except to say that the company was "considering its options" as Congress neared adjournment.

The maneuver represented a high-stakes gamble for Bethesda-based Lockheed. If it had succeeded, Lockheed could have immediately bought the remaining 51 percent of Comsat that it cannot acquire now, under the restrictions of the 1962 Satellite Act, which created Comsat.

Now Lockheed will have to wait until next year to see whether House and Senate negotiators can agree on changes to the Satellite Act, and sources said the issue will be taken up early next year. But then the company is likely to face tougher opposition.

The two houses have passed significantly different versions of changes in communications satellite policy.

But Lockheed is likely to face stiffer opposition from congressional critics angered by yesterday's move, legislative aides said.