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Lost in space: but calibration data from the X-ray telescopes on Abrixas may still be useful. Credit: CARL ZEISS

Astronomers around the world were last week lamenting the likely loss of Abrixas, a small German-built X-ray satellite whose batteries failed two days after a successful Russian launch.

Some were also suggesting that the failure has raised doubts about the apparently high level of risk associated with so-called ‘smaller, faster, cheaper’ science missions. These are favoured by space agencies in Europe and the United States as a way of introducing more flexibility into their launch schedules (see Nature 389, 899; 1997).

Abrixas was to have carried out the first complete broad-band all-sky survey with imaging telescopes in the medium-energy X-ray range, extending by an order of magnitude the survey performed by its predecessor ROSAT, which was shut down last year.

Abrixas was seen as a pathfinder for future large international X-ray missions, including the European Space Agency's XMM, the US space agency NASA's AXAF — recently renamed the Chandra X-ray Observatory — and Japan's Astro-E.

Scientists on these missions, each scheduled to be launched within the next nine months, had been hoping to study interesting X-ray sources identified by Abrixas.

But ground contact with the satellite was lost two days after its launch. At least one of its eleven battery cells appears to have been burnt out by inappropriate power input from batteries used to support the launch. This means that, although the scientific instruments seem to be working, the information they gather cannot be transmitted to Earth.

Engineers will be able to analyse the full extent of the damage during a six-day period at the end of next month when Abrixas moves into full sunlight and its solar panels become operational. But it seems unlikely that the battery system can be restored or the satellite's scientific mission fulfilled.

“This is not only a major disappointment to our German colleagues, but also a setback to the international astronomy community,” says X-ray astronomer Ken Pounds, professor of space physics at Britain's Leicester University. “We were looking forward to Abrixas pointing the way to the best use of the upcoming international missions.”

Claude Canizares, director of the Center for Space Research at the Massachusetts Institute of Technology, and principal investigator of a Chandra instrument, agrees that the situation is “very sad”. Not only would Abrixas have helped locate the best targets for Chandra to focus on, he says, but “it is also nice to have relatively low-cost, small, fast and clever missions in one's portfolio”.

Canizares says it is disconcerting that “so many small missions seem to be failing”. Only a few weeks ago, WIRE, a small NASA satellite that would have surveyed the infrared sky, failed because its protective cover was lost after launch (see Nature 398, 100; 1999). Solar radiation heated the spacecraft and its store of cryogenic fuel was boiled off within a few days. This ended the mission, as infrared detectors can only function at very low temperatures in space.

Canizares suggests that the Abrixas failure is likely to fuel debates on how to reconcile speed with quality control.

Martin Turner, professor of astrophysics at Leicester University, and principal investigator on an XMM instrument, echoes the concern about faster, cheaper missions. “The Abrixas people did everything right: they completed to launch within three years, at low cost [DM40 million],” he says. “Yet they were let down by a low-tech item, the batteries.”

Abrixas, like most scientific satellites, was not insured. Although the error is believed to be a design fault in the battery system, which was provided by the Bremen-based company OHB, a spokesman for the German space agency DLR, says that, if tests in June prove that the mission is dead, “it is not clear if any form of compensation could be expected”.

Joachim Trümper, director of the Max Planck Institute for Extraterrestrial Physics in Garching and head of the Abrixas project, is trying to remain positive. Although Abris may never yield scientific data, he says, calibration work on its novel X-ray camera may be done during the satellite's brief sunlight. The high-tech camera will also fly on XMM.