The Space Transportation System's seventh flight (STS-7) is all set to notch up a score of fresh commercial and scientific achievements. If space shuttle Challenger lifts off within its eight-minute ''launch window'' on June 18, America's first five-member crew is scheduled to begin the mission by deploying a Canadian commercial satellite June 19 and an Indonesian satellite the following day.
These two tasks seem to have become routine just in time. With the commercial satellite business now worth more than $2 billion a year, a reliable shuttle system is a key part of communication industry plans to add 80 satellites in the next three years to the 72 launched during the past 21 years.
Once the two satellites have been catapulted from the shuttle, Challenger's crew will turn to a series of experiments designed to expand the vehicle's usefulness. The most important tests involve the Canadian-built mechanical arm, or Remote Manipulator System (RMS), and the boxy West German SPAS-01 (Shuttle Pallet Satellite). Using the arm, Challenger's crew is scheduled to remove the 3,300-pound SPAS from the cargo bay, release it for a period of free flight, then return the complex package of cameras and scientific experiments to the cargo bay. The test is to be conducted twice.
At a press briefing here, STS-7 pilot Frederick C. Hauck said that the National Aeronautics and Space Administration (NASA) is ''very interested in how the orbiter interacts with a free-flying satellite.'' All five crew members will work together on the tricky procedures involved in releasing SPAS, flying in formation with it, and then recapturing it. SPAS will film the operation with an array of still, motion, and TV cameras. The complex SPAS maneuvers are part of the preparation for next year's planned rendezvous with the damaged Solar Maximum satellite.
In addition to having America's first five-member crew, STS-7 boasts America's first woman astronaut, Sally K. Ride, and the first shuttle astronaut scheduled to make a second trip, STS-7 commander Robert L. Crippen. If the mission goes as planned, STS-7 also will reach a milestone by landing June 24 at the Kennedy Space Center in Florida. Adverse weather conditions could force Challenger to land in California as previous flights have. But if the Florida landing goes ahead as planned, the shuttle program will have eliminated the extra costs and week's delay involved in flying the shuttle piggy-back from California to Florida.
Whatever STS-7 can do to reduce costs and demonstrate the space flight's commercial usefulness will be valuable at a time when the Reagan administration is pressuring NASA to make its programs more cost effective. Earlier this month NASA won a battle against Office of Management and Budget efforts to increase the prices charged for carrying commercial payloads. According to a White House directive, after fiscal year 1988, ''it is the government's intent to establish a full cost recovery policy for commercial and foreign space transportation flight operations.''
NASA's STS administrator, Maj. Gen. James A. Abrahamson, explains that this postponement of any hike in the shuttle's discount fares until FY 1989 ''provides confidence for our shuttle customers. . . .''
NASA officials remain embarrassed by a malfunctioning US Air Force rocket booster that has delayed putting the massive Tracking and Data Relay Satellite launched from STS-6 in April into its proper orbit. But NASA officials still hope that the TDRS will be operating in time to test it during the STS-7 flight.