Gregg Easterbrook's article on ways of reviving the space program {''Getting Back Into Space: 12 Cheap and Easy Ways,'' Outlook, Aug. 23} is mostly right. But Mr. Easterbrook suffers from a degree of cynicism that causes him to treat NASA a bit unfairly while ignoring the most crucial problem -- the failure of our nation's leaders to treat space policy issues seriously.

It is true, as Mr. Easterbrook says, that the original plans for the space shuttle called for a smaller vehicle that would be less expensive to operate. But Mr. Easterbrook is wrong when he says that the changes leading to the present shuttle configuration were promoted by NASA as a way of gaining a monopoly over launch services.

In fact, the larger payload size was required by the Defense Department (which had no booster large enough for the planned KH-11 and KH-12 spy satellites), while the solid-rocket booster configuration was the result of pressure from the Office of Management and Budget to keep up-front costs down in the early and mid-'70s. Everyone knew then that those changes would lead to higher operational costs than had originally been projected, but that was left to be another administration's problem -- which it has now become.

Mr. Easterbrook is also wrong in his assumption that funding for manned versus unmanned space missions is a zero-sum game, so that the only way to support unmanned planetary probes is to ''use the money saved'' by postponing the space station and failing to build a replacement Shuttle. The chance is slim that money ''saved'' by cutting manned programs would wind up in new planetary missions instead of in pork-barrel appropriations for military bases, water projects, etc. -- as demonstrated earlier this year when one senator proposed to cut the space station budget in order to free funds for community development block grants in his home state.

Besides, the amount of money spent on space (about $10 billion a year) isn't so much in a country that spends $100 billion a year on illegal drugs. We can afford both manned and unmanned missions.

Mr. Easterbrook is right to promote such inexpensive and workable options as the ''Big Dumb Booster'' concept. But he is wrong to treat NASA with the contempt that he normally reserves for defense contractors found guilty of fraud. That contempt causes Mr. Easterbrook to miss the most crucial problem, the vacuum in space policy making since the Kennedy/Johnson years.

Over the past two decades, NASA has produced a lot of results for surprisingly little money when compared with many other government agencies, and it has done so despite grossly inadequate leadership from Congress and the White House. Given adequate leadership, NASA can do much better. Without that leadership, all the cheap and easy fixes in the world won't do any good.

GLENN HARLAN REYNOLDS

Washington

As former director of the National Commission on Space, I was amused to see Gregg Easterbrook criticize the report of the National Commission on Space apparently for having been ''oblivious'' to Gramm-Rudman-Hollings (which we weren't), while hailing the report by Dr. Sally Ride as being ''pragmatic.''

The National Commission on Space report and the Ride report are almost identical in their recommendations. Both strongly support automated exploration of the solar system, an Earth-observing system for studying Earth itself and a lunar base as a stepping stone to eventual settlements on Mars. Both reject the notion of sending crews to Mars in a ''sprint'' manner.

The only significant difference between the two reports is that Dr. Ride proposes that humans return to the moon in the year 2000, five years earlier than we recommended. Thus, if anything, her proposal would cost more during the Gramm-Rudman-Hollings era than the commission's would.

I cannot discern the wide difference between the commission report and Dr. Ride's study that Mr. Easterbrook sees. Perhaps he did not notice that our report spanned 50 years, while Dr. Ride concentrated on only the next 15 to 20 years.

MARCIA S. SMITH

Arlington