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The second of two Earth-observing satellite projects designed to help jump-start a commercial remote sensing industry has been scrapped by the US space agency NASA after cost and schedule overruns. The cancellation of the Clark project follows the failure of its companion satellite, Lewis, shortly after its launch in August (see Nature 389, 108; 1997).

The two spacecraft were intended to develop techniques and technologies that would be useful to future Earth-observing satellites, including hyperspectral imaging and the ability to selectively ‘edit’ out undesirable images obscured by cloud cover to conserve data.

NASA has long known that Clark was in trouble. The project was announced in June 1994 and was due to launch in March 1996, but difficulties with some of the spacecraft's subsystems and delays associated with a new rocket built by Lockheed Martin Aerospace pushed the date back by more than two years.

While Clark was being developed, the company originally contracted to build it, CTA Inc. of Rockville, Maryland, was purchased by Orbital Sciences Corp. of Dulles, Virginia, which also makes the Pegasus rocket. NASA had hoped that Orbital would solve Clark's management woes, but the cost overruns and technical problems continued.

After a review team at NASA's Goddard Space Flight Center recommended cancellation earlier this year, agency administrator Daniel Goldin acted on repeated threats to terminate any agency development project that runs more than 15 per cent over budget.

The space agency spent about $55 million on Clark, but not all of that is lost. NASA will retain launch-vehicle services from Lockheed Martin, and some of the satellite subsystems can be used on future projects. Developers of the software algorithms for cloud editing expect to use the technique in other missions.

A report on the failure of the $71 million Lewis satellite is due from NASA this month. A panel chaired by Christine Anderson, director for space vehicles at the Air Force Research Laboratory in Albuquerque, New Mexico, investigated the incident and has already presented its findings to NASA.

TRW Inc., which built and operated Lewis, has completed an internal investigation, but is not commenting publicly on the reasons for the failure. NASA sources have said that deficiencies in tracking and monitoring the satellite's progress after launch were partly to blame. Lewis might have been saved, they say, if spacecraft operators been present in the control room during the period of several hours when the spacecraft first began to spin out of control.