6987142
submission
japan_dan writes:
ESA published a report yesterday on their hopes that today's Rosetta earth fly-by may help provide more date for those studying the Earth fly-by anomaly problem: Since 1990, scientists and mission controllers at ESA and NASA have noticed that their spacecraft sometimes experience a strange variation in the amount of orbital energy they exchange with Earth during planetary swingbys. The unexplained variation is noticed as a tiny difference in speed gained or lost during the swingby when comparing that predicted by fundamental physics and that actually measured after the event.
6444173
submission
japan_dan writes:
An interesting way to enable Earth-Mars communication even when the Sun occults the direct radio line-of-sight: ESA proposes placing a pair of continuous-thrusting relay sats — one in front and ahead, one behind and below — Mars, with both following so-called 'B-orbits' (non-Keplerian). This means the direction of thrust is perpendicular to the satellites' direction of flight, allowing them to 'hover' with both Earth and Mars in view.
5009745
story
Dusty writes
"After several false alarms, the Ulysses Mission is finally ending. According to the Spacecraft Operations Manager's latest status report, the last track will be on 30th June 2009 from 15:25 until 20:20 UTC. 'We've tried to bolster our dwindling tracking allocation with some success
by grabbing antenna time released on short notice (mostly by the Spitzer Project). However, weekly data return figures are now typically 10% or less. And soon, even 512 bps from 70m antennas will be a thing of the past.'
Further details about Ulysses' 18-year mission are available from NASA and the ESA. We discussed the failing spacecraft last summer when it looked like its fuel was going to freeze, but through clever engineering, experts managed to squeeze out another year.
