KENNEDY SPACE CENTER -- NASA's new $200-million Boeing Satellite Systems TDRS-H tracking and data relay satellite has malfunctioned in geosynchronous orbit. As a result, upgrades to the critical TDRS relay constellation are being delayed and, to date, NASA has refused to take ownership of the platform from the contractor.

An artist's concept of the TDRS-H satellite in space. Photo: Boeing

When the 3.5-ton TDRS-H was launched more than a year ago, NASA and Boeing managers hailed it as one of the country's most advanced and critically needed spacecraft (AW&ST July 3, 2000, p. 39).

But now TDRS-H represents another significant NASA mission problem, and personnel at NASA Headquarters, the Goddard Space Flight Center and Boeing have been told to keep the situation "quiet," agency officials said.

TDRS-H is supposed to be the flagship of an $830-million program to upgrade critical relay satellite capability used by NASA, the intelligence community, Europe and Japan. Instead, it is stuck in legal limbo at a temporary checkout position 24,000 mi. above the central Pacific.

The five current operational TDRS are all 6-11 years old and in need of eventual replacement. They are critical to shuttle, station and many unmanned spacecraft users. The new satellite's S- and Ku-band single-access systems for high-data-rate transmission from individual satellites are working normally and likely to be used operationally eventually.

But its multiple-access phased array system, critical to providing communications to up to five spacecraft simultaneously, is malfunctioning owing to either a design or a hardware failure.

The multiple-access capabilities of the new satellite were also to be more closely comparable to the high-data-rate single-access system capabilities.

TDRS-H continues to be tested, but more than a year after launch, it has not been moved to its planned operational location over eastern Micronesia or integrated into the aging TDRS fleet it was designed to begin to replace.

TDRS relays are also used by secret National Reconnaissance Office Lacrosse-type imaging radar spacecraft.

With TDRS workload growing to about 30 programs in the next few years from about 16 users now, the problems with the multiple-access system on the new vehicle could also have a significant effect on overall U.S. relay network capabilities.

The Tracking and Data Relay Satellite (TDRS-H) is prepped for launch. Photo: NASA-KSC

Neither NASA nor contractor personnel will discuss specifics of the problem while legal negotiations continue on the fate of the spacecraft -- or more likely, how much Boeing will be penalized for either design or parts failure. NASA, the Defense Dept. and international users need the capability from at least the single-access system, so the spacecraft is likely to enter at least partial service after the legal wrangling is over.

Hughes in a statement noted that the two follow-on spacecraft, TDRS-I and J, "are being modified" so they will not experience a "similar performance shortfall."

Boeing Satellite Systems "acknowledges that there has been a performance shortfall on the multiple-access phased array antenna. While not meeting specification, the affected services remain functional," the company said.

The operative words in the dispute, however, are "performance shortfall" and an admission by Boeing that the system does "not meet specification." This is important, since NASA used its new TDRS contract for commercially oriented procurement reforms.

Under the plan, NASA Goddard levied TDRS-H performance requirements -- instead of engineering specifications -- when seeking bids for the new spacecraft. During the ensuing competition, Boeing Satellite Systems (then Hughes Communications) defeated TRW, which had built the previous six TDRS launched by the shuttle. One of them has since been taken out of normal relay service while a seventh was lost on Challenger.

The specification-oriented procurement was to involve a delivery in orbit to NASA once the satellite had proven itself. But when the multiple-access system capabilities fell short, NASA used the new contract provisions to reject the spacecraft. Current negotiations are at an especially sensitive state, managers said.

The follow-on modified satellite, TDRS-I, recently was placed on the Cape Canaveral schedule for October, several months earlier than originally planned for launch.

The earlier launch date will assist getting a modified spacecraft aloft on the heels of problems with the first satellite. But NASA had decided to opt for an earlier launch anyway because of an opening in the International Launch Services Atlas-Centaur booster manifest.