National Aeronautics and Space Administration (NASA) officials are playing down their problems with a new communications satellite system. But until a multiagency investigation can explain NASA's failure to position the first Tracking and Data Relay Satellite (TDRS) correctly a month ago, plans to launch the next two $100 million satellites needed to complete the system are on hold.
The first impact of the delay will be on the maiden ''Spacelab'' mission scheduled for a Sept. 30 shuttle launch. If the first TDRS can be nudged into its proper orbit, NASA intends to fly the joint US-European Spacelab 1 as planned. But because this mission was intended to operate with two TDRS craft in orbit, the amount of data that Spacelab can relay to the ground will be cut by one-third because of limits to one satellite's coverage. If the first TDRS is not operating in time, then Spacelab will be postponed, with the next flight opportunity in February 1984.
Martin Goland, president of the Southwest Research Institute in San Antonio, says that every delay naturally disappoints the scientific community. He and fellow scientists look forward to more dependable delivery of their experiments into orbit and firmer guarantees that needed data will be relayed in full. But, says Dr. Goland, ''We also know that accidents do happen, particularly when you are using new procedures for the first time.'' He says he expects that NASA will solve the problems encountered with the US Air Force's Inertial Upper Stage (IUS) rocket used to boost TDRS from the shuttle's cargo bay into its higher orbit.
Lt. Col. Herbert G. Baker, US Air Force Space Division spokesman, says he is convinced that any IUS problems are well on the way to being solved. He says that a preliminary investigation of the malfunction that sent the TDRS tumbling out of control on April 5 has ''narrowed down'' the problem to apparent ''control anomalies.'' With a final report due late this month, Colonel Baker says that preparations are still going ahead for launching the second TDRS satellite as planned on the eighth shuttle flight in August.
But as long as the IUS malfunction remains unexplained, says NASA's TDRS program director Robert Aller, the prospect of launching the second TDRS in August remains ''very remote.''
Accordingly, NASA first polled the European and American scientific teams responsible for the 70 experiments being carried in the Spacelab. The scientists unanimously agreed to proceed with a Sept. 30 launch even if their ability to relay data is reduced.
In order to have TDRS-1 fully operational in time for a September Spacelab launch, NASA officials and private contractors are conducting a precise series of rocket firings. The procedure is complicated because some thruster rockets aboard TDRS-1 have overheated during test burns. Therefore, maneuvering the satellite into place may require 40 one-hour burns spread over the next five weeks. This added delay means that time is running out for the 90-day checkout period needed to put TDRS into full operation. So NASA teams are starting the checkout now rather than waiting until the satellite is raised to its fixed 22, 300-mile-high orbit.
Robert Clark, NASA project manager for Spacelab's life sciences experiments, explains that Spacelab's crew will carry an extra 30 videotapes to record data that can't be relayed directly to Earth. But without as much data relay as planned, some scientific data will be lost entirely, he says.
Despite Spacelab 1's TDRS problems, which have forced NASA to redesign several aspects of the mission, Dr. Clark's team is already fitting together the complex pieces of Spacelab 4, due to fly in December 1985.