Houston — As the space shuttle Discovery's maiden flight nears an end, its biggest accomplishments may have been to salvage the shuttle program's reputation for reliability and demonstrate the flight schedule's flexibility.
At this writing, the seven-day mission is scheduled to end Wednesday morning at Edwards Air Force Base in California.
Since the mission began last Thursday, the shuttle's six-member crew has successfully launched three communications satellites and tested a 102-foot-by- 13-foot solar panel that is designed to demonstrate the ability to build large-scale flexible structures in orbit.
The satellites include SBS-4, a corporate communications satellite lunched for Satellite Business System; Leasat 2, part of a worldwide communications system operated by Hughes Communications Services for the Defense Department; and AT&T's Telstar 3. The SBS-4 and Telstar 3 used PAM-D boosters to propel them toward their geosynchronous orbits at 22,300 miles above Earth. The three lauches brougt the National Aeronautics and Space Administration (NASA) $37 million.
Following the third deployment Saturday, President Reagan talked with the shuttle crew by radio-telephone from the White House and told them, "We've been following your exploits. You're doing a great job. . .You're 3 for 3."
Mission commander Henry Hartsfield told the President that flying a shuttle is "really a tremendous ride; you ought to try it sometime."
To which Mr. Reagan replied, "I'll think about that a while and see if I can't appoint myself as a passenger" -- an oblique reference to his recent order that NASA select a school teacher as the first civilian passenger to fly.
In addition, Charles Walker, an engineer for McDonnell Douglas who is the first nonastronaut to fly aboard a shuttle, is on this flight operating a continous-flow electrophoresis system, which separates materials in solution by subjecting them to an electric field. The object is to produce pharmaceuticals of greater purity than is possible on Earth. McDonnell Douglas and its partner in the venture, Johnson & Johnson, hope to mass produce a hormone which is the subject of the experiment, in space by 1987.
These and other activities are taking place on a mission that combined payloads from Discovery's maiden flight and its second flight. The Solar panel array was on the original manifest for for Discovery's first flight, while the three communications satellites were on the manifest for the orbiter's second flight. The object was to satisfy as many commercial customers as possible while doing the least damage to the shuttle program's launch schedule. As a result, several other cargoes, including one communications satellite and two photographic packages, had to be dropped from the manifest.
Discovery's satellite deployments are the first for commercial customers since February, when two communications payloads went into useless orbits because their PAM-D rocket boosters failed after successful launches from the shuttle Challenger.
Those failures caused NASA customers great concern, raised satellite insurance rates, and resulted in the delay of one satellite launch. That, plus the three postponements over two months of Discovery's maiden flight, had put the shuttle's reputation as an orbital delivery system in question.
Whether the shuttle can keep its promised launch schedules will now be put to the test. With this flight, the space agency has committed itself to a launch rate of one a month for the next 15 months, accelerating it to 16 a year after that.
The solar-panel experiments, operated by mission specialist Judy Resnik, went so well that the Mission Control sent up an additional "shopping list" of experiments. Such a solar panel could produce 12.5 kilowatts of power, enough to supply the power needs of four average households. Becuase the focus on this first flight test is on structure and dynamics, only three of the 84 sections of the panel are equipped with siliccon solar cells.
As for the status of the orbiter itself, Commander Hartsfield and pilot Michael Coats reported that the newest of NASA's shuttles was performing very well, except for a few "nit-picky" items: a sensor that didn't work, an antenna that sounded false failure alarms, and some housekeeping items. The crew, which also includes Steven Hawley and Richard Mullane, also complained about a jammed camera, hydrogen gas bubbles in their drinking water, and a dirty cabin.
In addition to these problems, ice formed at the outlets of the Discovery's sanitary station. The crew tried various methods to solve the problem. In one case thrusters were fired to try to dislodge the ice. The crew also oriented the orbiter so that the outlets faced the sun, in an attempt to melt the ice. All to no avail. Crew members were then instructed to use "Apollo bags," which are included to cover such contingencies.