NASA investigators believe the Genesis solar sample-return capsule plunged to Earth on 8 September due to "upside down" engineering drawings at spacecraft manufacturer Lockheed Martin. This resulted in the incorrect assembly and subsequent failure of a gravity switch intended to trigger deployment of the drogue chute after the re-entry capsule decelerated to a predetermined velocity. This prevented deployment of the main parafoil, which was to be snagged by a helicopter in an aerial recovery manoeuvre.
The capsule from the $264 million Genesis mission crashed into the Utah desert at 300km/h (185mph), although NASA believes some of the solar wind samples can be salvaged. NASA's Stardust spacecraft, heading home with comet samples for a re-entry in 2006, has the same type of capsule and parachute deployment system, but Lockheed Martin believes the gravity switch was properly installed on that spacecraft.
Lockheed Martin has been prime contractor on three other spacecraft involved in malfunctions. A polar-orbiting meteorological satellite fell to the floor in the company's Sunnyvale, California factory after bolts to hold the spacecraft on its cradle were removed. NASA's Mars Climate Orbiter was lost in 1999 as it tried to enter Mars orbit 170km (105 miles) too low because of software using imperial rather than metric measurements.
Loss of the Mars Polar Lander shortly after was probably due to "inadequate checks and balances", NASA said, which led to premature shutdown of the landing engines as a result of the shock created by deployment of the landing legs.
TIM FURNISS / LONDON
Source: Flight International
