spacetoday.net: MESSENGER flies past Mercury, suffers power glitch

Posted: Thu, Oct 1, 2009, 6:45 AM ET (1045 GMT)
MESSENGER illustration (JHUAPL)

A NASA spacecraft made its third flyby of the planet Mercury on Tuesday, but a problem with the spacecraft's power system caused the spacecraft to go into space mode, disrupting scientific observations. The MErcury Surface, Space ENvironment, GEochemistry, and Ranging (MESSENGER) spacecraft made its closest approach to the planet at 5:55 pm EDT (2155 GMT) Tuesday, passing 228 kilometers above the planet's surface. The flyby was the last of three planned for the spacecraft before it goes into orbit around the planet in March 2011. While the spacecraft took some images and collected other data as it approached the planet, MESSENGER went into safe mode about four minutes before closest approach. Project officials believe that "an unexpected configuration of the power system" while the spacecraft was in the planet's shadow triggered the safe mode. All the data collected prior to entering safe mode has been transmitted to Earth, although planned observations during closest approach were lost.