US scientists are still unable to make contact with a comet-chasing satellite, more than 30 hours after a crucial engine burn was scheduled to take place.
CONTOUR鈥檚 solid-propellant rocket motor was due to deliver a burst of thrust to propel the spacecraft out of an Earth orbit at 0949 GMT on 15 August.
The spacecraft failed to relay a message to confirm the manoeuvre went as planned, and further attempts to locate and communicate with CONTOUR have been unsuccessful.
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鈥淲e鈥檙e working on the assumption that it鈥檚 been pushed out of orbit,鈥� Mike Buckley of Johns Hopkins University鈥檚 Applied Physics Laboratory told 快猫短视频. 鈥淚t all really hangs on getting a signal.鈥�
But Buckley admits the $159m mission now hangs in the balance. 鈥淯ntil they make contact it鈥檚 very difficult to say what sort of shape it鈥檚 in,鈥� he says.
Mission critical
Controllers still have little idea what happened. The engine burn could have pushed the spacecraft out of position so that its antennas are facing the wrong way, or it may have caused the spacecraft to shut down.
Keith Cowling, editor of NASAWatch.com, says CONTOUR could have even entered a 鈥渃atastrophic safe mode鈥� from which it cannot be woken.
A more serious malfunction with the propulsion system might have caused permanent damage or even destroyed the spacecraft completely.
Cowling says the spacecraft鈥檚 propulsion system may well have suffered a malfunction, because contact was lost shortly after it was scheduled to fire. 鈥淭he time it happened troubles me,鈥� he says.
Close encounter
CONTOUR launched on 3 July 2002. It was scheduled to fly to within 100 kilometres of two comets during its six-year mission. NASA鈥檚 plan was to capture surface images and study the chemical composition of each comet鈥檚 trail. Only two images of comet nuclei exist because photographs must be take at close range.
鈥淚t is a big loss to the comet science if indeed it is lost,鈥� says Andrew Coates, at University College London鈥檚 Mullard Space Science Laboratory. 鈥淚t鈥檚 an important mission and this is a niche science.鈥�
But there are more crucial comet missions planned, Coates says.
These include the European Space Agency鈥檚 Rosetta spacecraft, which is set to launch in January 2003 and land on a comet in 2006. 鈥淚 would be more worried if there was a problem with Rosetta, because of all the instruments on board,鈥� he says.
Other comet missions are also in the pipeline. NASA鈥檚 Stardust, which launched in February 1999, is set to capture dust from around a comet in 2006. NASA also plans to launch Deep Impact in 2004, which will attempt to blow a hole in a comet.