April 8, 1983

Two astronauts glided, tumbled and somersaulted through the vacuum of space today in a successful test of their abilities to serve as orbital repairmen. Bundled in thick white spacesuits, they stepped out of the Challenger's cabin like children going out for a romp in the snow. The astronauts, tethered to keep from drifting away, ''walked'' to the rear of the space shuttle's 60-foot-long cargo bay and forward again, checking their maneuverability in the new, more flexible 250-pound suits on which their lives depended. Working in the open cargo bay, they practiced rigging a winch cable, unstowing and handling tools and generally evaluating how well astronauts of the future could perform repairs on satellites or on the shuttles themselves.

A bipartisan majority of the Senate Budget Committee today approved a 5 percent increase in the military budget next year, just half the increase that President Reagan has insisted is necessary for the nation's security. The vote was 17 to 4. Eight Republicans, including the committee chairman, Pete V. Domenici of New Mexico, joined nine Democrats in voting for a rise of only 5 percent after making up for the effects of inflation. Four Republicans voted against it, and one Democrat, Ernest F. Hollings, of South Carolina, was absent.

A NEW tradition may be entrenching itself in the art world, that of the two-gallery show. Initiated by the dealers Mary Boone and Leo Castelli, with whom most of such shared exhibitions have taken place, it goes like this: A ''hot'' artist produces so much work, or work of such a size, as to require his dealer to find more than one space - usually that of another dealer - in which to show it. What this provides for the artist, of course, is more impact; the cachet of a double exhibition, and twice the publicity. As for the viewer, he or she gets to see a larger slice of the artist's effort, while at the same time developing a possibly exaggerated idea of his importance. And the dealer? Ah, the dealer. His artist (and he) may benefit from the extra fanfare, but on the other hand, the double show not only requires more arranging; it also involves the risk of ''sharing'' him with another gallery. Nevertheless, the concept may be here to stay, taking off from the two-gallery shows already racked up this year by Julian Schnabel, David Salle and Robert Morris, among others.

More than 40 churches around the country are giving sanctuary to illegal aliens from Central America who would face deportation to their war-torn nations if they were caught by Government agents. Hundreds of other churches, with the support of some of the nation's largest religious denominations, have pledged to give support to the refugees, most of them Salvadorans and Guatemalans who have been denied political asylum. By giving temporary shelter until the refugees can be resettled with families, some church leaders say, the churches are taking a humanitarian stand and calling attention to what they consider the unfair application of the Refugee Act of 1980. The act requires refugees requesting political asylum to prove to both the Attorney General's office and the United States Immigration and Naturalization Service that they would be persecuted if they returned to their homeland. Some church leaders oppose sanctuary as a form of civil disobedience, but a Government spokesman said it was not clear if the churches were violating any laws in harboring the illegal aliens.

New York City's freshly painted white subway cars are quickly turning all shades of red, green, blue and black. Graffiti scrawlers have struck the white cars to such an extent that Transit Authority officials are now considering halting the creation of what they once envisioned as ''a great white fleet.'' To date, about 25 percent of the system's 6,000 cars have been painted with a graffiti-resistant white compound. The cost has been $2,200 a car.