Space exploration rarely gives second chances, but the Japanese Aerospace Exploration Agency (JAXA) took advantage of a big one today. The Agency has confirmed that its Akatsuki space probe has successfully made it into orbit around the planet Venus on its second attempt. The first try was way back on December 7, 2010, when a malfunction of the main engine sent the spacecraft back into orbit around the Sun.
The unmanned spacecraft successfully fired its auxiliary reaction control system (RCS) thrusters at 23:51 GMT under automatic control for a 20 minute burn. The maneuver was monitored by Japan's Usuda Deep Space Center and the Canberra Deep Space Network tracking stations. After completing the burn, Akatsuki rotated into a new position to execute a second maneuver on command from Earth in case the first was insufficient, but this subsequently proved to be unnecessary.
The Akatsuki Venus Climate Orbiter or Planet-C project was launched from the Tanegashima Space Center in Japan on May 21, 2010 atop an H-IIA 202 rocket along with the IKAROS solar sail craft. Tasked with studying the Venusian atmosphere in hopes of predicting its behavior, it has three infrared cameras, an ultraviolet imager, a lightning and airglow camera, and an ultra-stable oscillator for radio observations.
Today's maneuver was made necessary due to the accident that occurred on Akatsuki's first attempt. During its orbit insertion burn, communications went into blackout as expected when it passed behind the planet. However, the spacecraft failed to re-establish contact as programmed and mission control later discovered it was off course and drifting in safe mode.
Telemetry from the orbiter indicated that the main hydrazine/nitrogen tetroxide engine had shut down three minutes too early, sending the Akatsuki back into heliocentric orbit. Engineers later determined that the problem lay in a faulty helium valve that forced too much oxidizer into the engine's combustion chamber. This caused it to quickly overheat, damaging the engine.
To salvage the mission, JAXA put the spacecraft into hibernation and worked out a plan to use the eight RCS thrusters to alter Akatsuki's trajectory and send it on a course that would bring it back to Venus. The plan worked.
JAXA says it will spend the next two days establishing the parameters of the new orbit before starting planetary observations.
Source: JAXA
