MESSENGER gains speed
Thu Oct 16, 2008 at 10:14 UTC
Shortly after 08:00 UTC on Oct. 15, MESSENGER reached its greatest speed relative to the Sun. The spacecraft, nearly 70% closer to the Sun than Earth, was traveling nearly 140,880 miles per hour (62.979 kilometers per second) relative to the Sun. At this speed MESSENGER would traverse the distance from Earth to Earth's Moon in only 1.7 hours!
Even at this great speed MESSENGER is slightly slower than the fastest spacecraft: Helios 2. That spacecraft – launched into a solar orbit on January 15, 1976 – reached a top speed of 157,078 miles per hour (70.220 kilometers per second) relative to the Sun in April of 1976.
Because of MESSENGER's near-perfect Mercury flyby trajectory on October 6, the mission design and navigation team decided that a trajectory-correction maneuver (TCM) scheduled for October 28 will not be needed. The next maneuver for the mission, scheduled to be carried out in two parts on December 4 and December 8, will re-target the spacecraft for the third and final encounter with Mercury in just under a year on September 29, 2009.
| Source: Johns Hopkins University Applied Physics Laboratory | |
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