Hayabusa Re-Entry

Hayabusa Return Logo
Woomera Prohibited Area

Government of Australia’s document closing the
Woomera Prohibited Area during the re-entry
of the Hayabusa asteroid sample return vehicle.

Image Credit: Government of Australia

Hayabusa is expected to re-enter the atmosphere over western Australia 6:51 AM Phoenix Time (13:51 UTC) Sunday 13 June 2010, following a seven year journey to the asteroid Itokawa and back.

Hayabusa Trajectory
Hayabusa Trajectory with Asteroid Itokawa as of 29 August 2009.

Image Credit: JAXA

Hayabusa was launched on 9 May 2003 by the M-V-5 Rocket from the Uchinoura Space Center on Kogashima on the southern tip of Japan. The spacecraft arrived in the vicinity of the asteroid Itokawa on 12 September 2005. During the descent to the surface, damage to the thruster system occurred, and eventually all propellant was lost, including that required for the return trip.

On 25 April 2007, the homeward journey began with the firing of all three of the chambers in the ion engine. During 2008, the spacecraft reached its furthest distance from the Earth. During 2009, there was an anomaly with the ion engine, and the two remaining chambers were used to continue the voyage. Currently, only one chamber remains operational, and has been used for all remaining guidance and mid-course corrections. Due to the small thrust, firings as long as 6 hours are required for even the small delta-v changes.

NASA has made the following commitment to cover the return of the spacecraft:

An attempt will be made to provide a live video feed of the Hayabusa Re-Entry in the minutes around the re-entry at 13:51 UT, Sunday June 13. The video will be chosen from cameras operated onboard NASA’s DC-8 Airborne Laboratory by Jesse Carpenter and Greg Merkes of NASA Ames Research Center, or those operated by Ron Dantowitz, Marek Kozubal, James Brietmeyer and Brigitte Berman of Clay Center Observatory, or those operated by Mike Taylor and Jonathan Snively of Utah State University. Please note that such downlinks have proven very difficult in past missions. The Hayabusa re-entry will be fainter than that of ATV-1 “Jules Verne” in 2008. Also, the video feed will be transmitted by the DC-8 aircraft via INMARSAT and may not be of high quality. Large volumes of traffic on this website may hinder watching this live feed. For that reason, shortly after the re-entry, we plan to upload higher quality video, first via the INMARSAT uplink on our way back, and later, after we land at Melbourne, via an internet communication.

Hayabusa re-entry diagram

Hayabusa Re-Entry Schematic

Image Credit: Tetsuya Yamada, JAXA

The NASA page on hyper-velocity re-entries is here.

The 40-cm diameter capsule will be detached from the main spacecraft when passing the Moon’s orbit, put in a 5 rotations/second spin. Depending on the time of release, it will have moved about 2-5 km ahead of the main spacecraft when reaching atmospheric interface at 200 km altitude.

Below 40 km, the capsule will have been slowed down enough by the atmosphere to no longer emit visible light. Once the capsule reaches 10 km altitude, the heat shield is separated and falls to the ground (see figure above, courtesy of Tetsuya Yamada, JAXA). The exact point of where the heat shield is released (and the parachute is opened) has an uncertainty of about 100 x 15 km. To help recover the heat shield, the trajectory of the capsule is determined from the meteor observations.

The Sample Return Capsule will be floated to the ground by means of a parachute. Due to upper atmosphere winds, the capsule can end up quite far from the point of release. To be able to recover the capsule, the parachute is given a high reflectivity for radar signals, and the capsule has a radio responder.

NSS Phoenix expects to begin live blog of the re-entry Sunday morning around 6:00 AM Phoenix Time (9:00 AM EDT and 13:00 UTC).

  • Live Video – around 13:45 – 13:55 UTC = 6:45 – 6:55 AM Phoenix Time 13 June 2010
  • Post-event video – around 13:55 – 15:00 UTC = 6:55 – 8:00 AM Phoenix Time
  • Post-landing video – expected around 16:00 – 17:00 UTC = 9:00 – 10:00 AM Phoenix Time