Even before the destruction last week of the space shuttle Challenger, the nation's preeminent space program was beset with serious financial and bureaucratic problems, including reluctant customers, extraordinary cost overruns and a White House determined to make the shuttle pay for itself, according to government documents and informed officials.

For the last year, the National Aeronautics and Space Administration has been under pressure to reduce shuttle costs and simultaneously increase the number of launches, according to NASA testimony to Congress. Much of that pressure came from National Security Decision Directive No. 144 signed by President Reagan on Aug. 15, 1984, which ordered the space agency to develop a "fully operational and cost effective" shuttle program by Aug. 1, 1988.

The intent of the so-called National Space Strategy was to shift the shuttle program from primarily a research and development vehicle to an efficient space transport system featuring a fleet of four shuttles that would pay its own way as though it were a commercial cargo carrier, according to one former NASA official.

Although there is no evidence tying the Jan. 28 catastrophe to NASA's drive to lower costs and increase the number of launches, a close look at the history of the shuttle reveals a program constantly struggling to justify its ambitions, which ranged from being a floating laboratory to becoming the world's primary space trucking service.

Fifteen years of shifting requirements, faulty projections, budget cuts, soaring costs, technical snafus and interagency battles had taken a toll on NASA programs. The array of problems rarely came to the attention of a public that has been more intrigued by awesome color pictures from space and entertaining chatter from astronauts floating scores of miles above the Earth.

Beyond the immediate need to guarantee the safety of future flights, the Reagan administration and Congress also face a broader set of questions. Should the manned shuttle remain this country's primary space launch vehicle for military, government and commercial payloads? Or should the shuttle be reserved for special missions that require human skills, such as repair or laboratory work, with the task of heaving satellites and other objects into space left to unmanned rockets?

Shortly after NASA decided to make the manned shuttle its main space launch system in the early 1970s, serious questions arose about whether it could meet that goal. For one thing, Congress would only agree to finance four shuttles instead of the originally hoped-for five because of huge cost overruns.

NASA officials, struggling to keep the shuttle viable with the money provided, appear never to have forced themselves to prepare for the kind of calamity that occurred last week, according to government documents. Asked last year by a House subcommittee whether an "unforeseen accident" would require an additional shuttle, the agency responded that "the probability of a major accident to one of the existing orbiters is small."

James M. Beggs, NASA administrator (now on leave pending resolution of an indictment related to alleged activities he engaged in before assuming his government post), summed up that attitude last year before a Senate committee: "The shuttle is a flying machine. The way you learn about flying machines, at least in my experience, and I spent most of my life in this industry, is that you fly them. You fly them until something breaks and then you fix it. That is what we are doing on the shuttle."

A March 1985 report by NASA's Shuttle Operations Strategic Planning Group, however, questioned that optimism. "Because there are only four orbiters," the group warned, "concepts [such] as 'production line' and 'fleets' in the sense employed in most other transportation modes don't apply."

A former top Pentagon space official put it differently: "A 90 to 95 percent success rate is good in the space rocket business," but the shuttle needed 100 percent success to sustain full public and congressional support.

The Reagan effort to make the shuttle pay for itself -- which translated the rhetoric of previous administrations into action -- began in earnest last year.

For example, the "turnaround time" for preparing a new shuttle launch after completing a mission has been cut in half. It dropped from 100 days three years ago to 53 days last year, according to information NASA provided to Congress. This year's target was 36 days, with an eventual goal of 28 days, according to NASA.

To save money, NASA consolidated service contracts at Kennedy Space Center and cut the number of managerial personnel involved in launches. Government documents released this week show a pattern in recent months of accidents, personnel problems and low performance ratings marring the contracts of the Lockheed Space Operations Co.

At the Johnson Space Center in Houston, NASA told Congress, supervisory work on launches was being changed to "streamline operations . . . moving from a process which was manpower intensive, customized for each mission" to one that is "labor saving, hardware and software intensive, standardized wherever possible and highly automated."

Despite these streamlining efforts, few experts inside or outside the government believe the shuttle program could have come close to breaking even financially. An April 1985 House Appropriations Committee investigation of space shuttle economics found NASA officials warning that "a preoccupation with commercialization of launch services could adversely impact the overall program."

Last year, NASA reported to Congress that it had been reimbursed for only 24 percent of shuttle flight expenses. A NASA finance study also showed that if the agency raised the price per launch to make them cost effective, government and civilian users of the shuttle flights would cut back their business.

In fact, NASA's biggest problem recently has not been wooing new customers but rather keeping the ones it already has. Commercial customers have cut back on their projected use of the shuttle -- in part because of competition from the European space consortium, Ariane -- and the Pentagon has taken steps to shift some of its business to unmanned rockets launched from California.

The reality of the shuttle in 1986 is a striking contrast to the dreams of the 1970s. Eight years ago, the Carter administration projected seven times more Spacelab flights in the first 12 years of shuttle operation than are now scheduled. Military launches, always the backbone of the shuttle, are down 33 percent from projections in the 1970s, according to NASA documents.

Since the birth of the shuttle, NASA has had a love-hate relationship with the Pentagon. The civilian agency recognized that its program would always play second fiddle to national security, according to government officials. Thus NASA tailored its agenda to keep the military involved.

For example, the compact spacecraft NASA wanted originally nearly doubled in size to accommodate military specifications, one participating official said.

At key moments in shuttle funding history, the Defense Department was a crucial player. By threatening to pull out, the Pentagon even throttled overrun-inspired talk of limiting the shuttle program to two vehicles.

Recently, when the shuttle schedule began slipping because of repeated launch delays, the Air Force pressed for a new generation of its own launching rockets, despite an interagency agreement to halt all unmanned launches once the four-shuttle fleet became operational.

In 1984, the White House agreed to allow the Air Force to launch some military satellites with a new Air Force rocket. As spelled out in a directive signed by Reagan, the military agreed to pay for one-third of the shuttle's launch capability, while also building 10 new large rocket boosters to orbit military satellites that previously could only be carried by the shuttle.

Not satisfied with that, the Air Force proposed reconfiguring old Titan II missiles being dismantled as intercontinental ballistic missiles. These refurbished Titan IIs would enable the Air Force to launch smaller satellites into orbit. The service even tried to get the National Oceanic and Atmospheric Administration to drop its commitment to NASA to carry its three future weather satellites and instead rebuild them to be launched on the Air Force Titan II, according to congressional testimony.

After almost 12 months of wrangling inside the government and on Capitol Hill, NOAA satellites were returned to the shuttle, but the Air Force got approval to launch several of its own satellites on the Titan IIs.

As a result, NASA reported to the House Space Science committee last year, "Shuttle operations funding requirements have increased as a result of the net effect of reduction in the amount of anticipated reimbursements, both from the Department of Defense and foreign and commercial users."

In contrast to congressional charges that the military has been seeking to take over the space program, NASA appears to have been hard put just to keep the Pentagon involved.

As part of its cost-cutting strategy, NASA put forward an ambitious launching schedule in an effort to shave the price per launch. NASA officials projected that by 1989 they could carry out 24 launches per year -- if they had four shuttles. "Only within NASA," the House Appropriations Committee investigation found, "is there any optimism that such a launch rate can be achieved and sustained."

In 1983, a National Academy of Sciences study said that at best NASA could achieve 17 to 25 launches a year, an estimate that "did not attempt to account for anomaly [unusual] and failure-resolution delays, diverted landings, or accidents."

During congressional hearings last year, NASA officials demonstrated how apparently minor changes in their program had heavy financial implications. For example, officials pointed out that when a shuttle was forced to land at an alternative runway because of bad weather or other factors it cost an additional $800,000.

Cost overruns and delays have haunted the shuttle as persistently as any Pentagon weapons program. Originally priced at $5 billion, the program spiraled to $18 billion and is also running five years behind schedule, according to congressional testimony. Similar overruns have plagued NASA's satellite programs associated with the shuttle.

The loss of the TDRS2 communications satellite in the Challenger accident illustrates the interrelationship of NASA's problems and how remote the goal of cost effectiveness appears.

That lost satellite was to be the second of three satellites in the Tracking and Data Relay System (TDRS) designed to carry NASA communications between deep space and Earth.

Originally priced at $810 million for three operating satellites and three backup satellites, the program was beset with technical problems and shuttle delays that drove the cost to $2.8 billion by 1984, according to information provided to Congress.

NASA planned to have the system operating by late last year and thus had begun disbanding its worldwide, ground-based communications network. One NASA official told Congress that funding for the ground-based system ceased at the beginning of 1986, and that it would cost an additional $3.5 million a month to keep the ground system operating if TDRS was delayed, as has now happened.

A side effect of the TDRS delay, Congress was told, is the shuttle's inability to process advanced data generated by some planned onboard experiments.

The Hubble space telescope, scheduled to go aloft in the shuttle Atlantis in August to allow scientists to see objects in deep space, was originally priced at $550 million. Because of overruns, the telescope program will now cost $1.2 billion, NASA told Congress.

NASA's Centaur program illustrates yet another NASA predicament. This $800 million program, begun in July 1982, was supposed to develop a new upper stage rocket to be launched from a shuttle and carry a satellite to deep space or into geosynchronous orbit nearly 20,000 miles from Earth.

The original NASA target for the first two Centaur rockets was this May, when the Galileo and Ulysses spacecraft would be carried to deep space. To exploit planet alignments, the Galileo device was to be sent toward Jupiter; Ulysses, also called the "solar polar" mission, was to study the sun at latitudes that cannot be studied from Earth's orbit.

Both shuttle missions, which were to go within a 15-day span, depend on the success of the Centaur rocket. But by last February, the main contractors and subcontractors for the project were already working seven-day weeks, three shifts a day, Congress was told. NASA reported in February that the cost overrun associated with the program would be $40 million.

Just two months later, NASA Administrator Beggs told a Senate committee, "What we are looking at is an overrun [on Centaur] that is from $70 million to $100 million."

He assured Congress, however, that the Air Force would pay a portion of the overrun because the service was a partner in the program and two of its intelligence satellites were scheduled for launch on the second pair of Centaurs.