On November 25th, 2005, the spacecraft Hayabusa landed on the surface of asteroid Itokawa, but JAXA's mission controllers didn't know about it for hours. Under autonomous control, the spacecraft tightly followed the planned decent curve to the asteroid, released a target marker, slowed, bounced twice, and then landed gently on the surface.
Planned vs. actual descent path.
Mission specialists were surprised when the data was analyzed and it became clear that a landing had taken place. They had initially reported that the landing had been "waved off" by onboard control, and were waiting for the return-to-orbit telemetry to restart. When the telemetry did not automatically reconnect, JAXA engineers assumed a fatal error and possible loss of the craft. Mission guidelines called for sending an "emergency landing abort" signal to the spacecraft. Some independent news reports stated that the craft had been lost.
Hours later communication was reestablished, and only then did JAXA learn of their partial success.
The data received from Hayabusa show an unusual string of logic controls that allowed the craft to approach, and then land under it's own volition. Thinking they had lost the spacecraft, the engineers sent emergency abort orders to Hayabusa, only to find out later that their craft had indeed landed on the asteroid, and had been waiting 30 minutes for further commands. Due to the odd functions surrounding the landing event, Hayabusa's Touch Down Sensor did not activate and the sampling functions were not deployed.
The abort orders received 30 minutes after landing activated the craft's propulsion system, Hayabusa moved back into a control orbit above the surface of the asteroid, and began sending news back to earth of it's brief contact with Asteroid Itokawa.
Target marker (circled) separated from Hayabusa. The black shape is the spacecraft's shadow.
Additional landing are scheduled, and JAXA hopes to take samples of the asteroid's surface which will be returned to earth for analysis.
If you want to read (decipher) the JAXA news release visit SpaceRef, because even with Japanese characters, JAXA's website is a complete mystery.
(You've got Asteroids? Cool! )
Article comments
1 - Victor Plenty
Cool news, but not the first asteroid landing. Back in February 2001, NASA and JPL guided the Near Earth Asteroid Rendezvous spacecraft (NEAR-Shoemaker) to land intact on the surface of asteroid 433 Eros.
However, it is true that this Japanese spacecraft is the first to successfully take off again after landing on an asteroid.
2 - Bennett
You are correct Victor, and I've fixed my headline to reflect that.
Ya see, there I was, almost done with this and I was trying to come up with that perfect, snappy headline... Yeah... That'll work!
Where IS my personal editor these days?
Cheers!
3 - Victor Plenty
I've toyed with trying to be an editor here, but Erice & Co would probably tell me it isn't quite sufficient to drop by every few months and point out a few typos and other minor glitches before disappearing into the duties of my paying job again.
Thanks for keeping us up to date on the significant events happening out there in the spaces between worlds, Bennett.
4 - Tan The Man
Wow. Score one for other space agencies not named NASA.