End is not NEAR

 作者:门谠纱     |      日期:2019-03-07 08:04:05
By Damian Carrington Mission controllers have decided to delay saying farewell to the first spacecraft to land on an asteroid for an extra 10 days. NASA’s Near Earth Asteroid Rendezvous craft touched down on Eros on Monday, a remarkable feat given that the craft was never intended to be grounded. A gentle landing at just over 6 km/h left the car-sized craft intact and still talking to Earth. Communications were due to be switched off on Wednesday, exactly a year after NEAR began orbiting Eros. But the soft landing and favourable positioning of the solar panels means a gamma ray spectrometer on board can be activated to measure the composition of the asteroid from a few inches away, rather than a few miles. “These measurements have the potential of improving the precision of our knowledge about these abundances by a factor of 10,” said NASA’s Jay Bergstralh. Other instruments will not be used because data is being relayed via a backup, low-gain antenna – the primary one is pointing the wrong way. Sending images with the data transfer rate down to 10 bits per second would give far less scientific return than the spectrometer data. More at: