| NSSDC Master Catalog: Spacecraft |
NSSDC ID:2003-019A
Launch Date/Time: 2003-05-09 at 04:29:25 UTC
On-orbit Dry Mass: 415 kg
The primary scientific objective of the Hayabusa (formerly Muses-C) mission is to collect a surface sample of material from an asteroid (25143 Itokawa/1998 SF36) and return the sample to Earth for analysis. It is also a technology demonstration mission. Other scientific objectives of the mission include detailed studies of the asteroid's shape, spin state, topography, color, composition, density, photometric and polarimetric properties, interior and history.
Mission Profile
The spacecraft was launched on 9 May 2003 at 04:29:25 UT (1:29 p.m. local time, 12:29 a.m. EDT) on an M-5 solid fuel booster from the Kagoshima launch center. Following launch, the name Muses-C was changed to Hayabusa (the Japanese word for falcon) and the spacecraft was put into a transfer orbit to bring it to asteroid 25143 Itokawa (1998 SF36), a 0.3 x 0.7 km near-Earth object. The ion engines were successfully test-fired starting on 27 May to the middle of June, 2003. Hayabusa flew by Earth on 19 May 2004 at an altitude of 3725 km at 6:23 UT. Rendezvous with the asteroid will occur in June 2005. Note that the spacecraft will not go into orbit around the asteroid, but will remain in a station-keeping heliocentric orbit close by. Hayabusa will initially survey the asteroid surface for about three months from a distance of about 20 km in the "home position", a region roughly on a line connecting the Earth with the asteroid on the sunward side. This is global mapping phase 1, the phase angle during this phase will be small, no greater than 20 - 25 degrees. Global mapping phase 2, which will last for about a week, will take place from a position near the terminator, affording high phase angle views of the asteroid. Following this the spacecraft will move back to the home position and then move close to the surface for a series of soft landings and collection of samples at three sites. On-board optical navigation will be employed extensively during this period because the long communication delay prohibits ground-based real-time commanding. The samples, with a total mass of approximately one gram, will be held inside a separate re-entry capsule. (The lander was also to deploy a small rover supplied by NASA onto the surface of the asteroid, but the rover was cancelled by NASA due to budget constraints.) All operations at Itokawa must take into account the extremely low gravity at the asteroid's surface. After a few months in close proximity to the asteroid, the spacecraft will fire its engines to begin its cruise back to Earth. The re-entry capsule will be detached from the main spacecraft at a distance of about 300,000 to 400,000 km from the Earth, and the capsule will coast on a ballistic trajectory, re-entering the Earth's atmosphere in June 2007. The capsule will experience peak decellerations of about 25 G and heating rates approximately 30 times those experienced by the Apollo spacecraft. It will land via parachute near Woomera, Australia. This scenario is a change from the original plan to launch in July 2002 to the asteroid Nereus.
Spacecraft and Subsystems
The Hayabusa spacecraft has a box-shaped main body 1.5 m along each side and 1.05 m high. The launch mass is 530 kg, including 50 kg of chemical propellant and 65 kg of xenon gas. Two solar panel wings with a total array area of 12 square meters protrude from the side and a 1.5 m diameter high-gain parabolic antenna is mounted on top on a two-axis gimbal. Hayabusa will be propelled during cruise phases by two microwave ion thruster engines, which use a microwave discharge to ionize xenon gas. The ionized plasma is accelerated by high-voltage electrodes through four thruster heads which protrude from one side of the spacecraft body to provide a peak thrust of 20 mN using 1 kW power. A nitrogen tetroxide/hydrazine propulsion system with a peak thrust of 22 N will be used for maneuvering. The spacecraft will be powered by gallium-arsenide solar cells producing 700 kW at 1 AU and a 15 A-hr rechargeable nickel-metal hydride (Ni-MH) battery. Communications will be via X- and S-band low gain antennas and the high gain dish antenna (X-band) with a transmitted power of 20 W. The mission will also be equipped with a camera, which will be used for imaging, visible-polarimetry studies, and optical navigation near the asteroid, a laser ranging device (LIDAR), and near-IR and X-ray spectrometers. The insulated and cushioned re-entry capsule, 40 cm in diameter and 25 cm deep with a mass of about 20 kg, is attached to the body of the spacecraft near the sample collection horn. The capsule has a convex nose covered with a 3 cm thick ablative heat shield to protect the samples from the high velocity (~13 km/s) re-entry. Cost of the Hayabusa spacecraft is roughly 12 billion yen ($100 million U.S.)
Surface Sample Collection
The lander will be equipped with a universal sample collection device which will gather roughly one gram of surface samples taken from the landings at 3 different locations. The device consists of a funnel-shaped collection horn, 40 cm in diameter at the end, which is to be placed over the sampling area. A pyrotechnic device fires a 10 gram metal projectile down the barrel of the horn at 200 - 300 m/sec. The projectile strikes the surface producing a small impact crater in the surface of the asteroid and propelling ejecta fragments back up the horn, where some of it is funnelled into a sample collection chamber. Prior to each sampling run, the spacecraft will drop a small target plate onto the surface from about 30 m altitude to use as a landmark to ensure the relative horizontal velocity between the spacecraft and asteroid surface is zero during the sampling. After sampling the samples will be stored in the re-entry capsule for return to Earth.
Rover
The rover, or Small Science Vehicle (SSV), was to have been a NASA contribution to the mission but was cancelled due to budget contraints. The SSV would have been dropped onto the surface of the asteroid by the Hayabusa spacecraft. The rover goals were to make texture, composition and morphology measurements of the surface layer at scales smaller than 1 cm, investigations of lateral heterogeneity at small scales, investigation of vertical regolith structure by taking advantage of disturbances of the surface layer by microrover operations, and to measure constraints on the mechanical and thermal properties of the surface layer. The rover would weigh about 1 kg and would be capable of rolling, climbing, or hopping around on the surface of the asteroid. It would have run on solar power and carry a multi-band imaging camera, a near-infrared point spectrometer, and an alpha/X-ray spectrometer (AXS).
Planetary Science
Technology Applications
Institute of Space and Aeronautical Science, U of Tokyo/Japan
National Aeronautics and Space Administration/United States
![[CONTOUR diagram]](https://webharvest.gov/peth04/20041031100325/http://nssdc.gsfc.nasa.gov/planetary/image/muses_c_diagram.jpg)
MUSES-C Testing Status Report - 06 August 2002
MUSES-C Rover Cancelled - 03 November 2000 NASA Press Release
Change in MUSES-C Target and Launch Date - 07 August 2000 NASA Press Release
Asteroid Page Asteroid Fact Sheet May 1997 Press Release -
NASA Rover and involvement with the mission.
Muses-C Home Page - ISAS, Japan Muses-C Description - ISAS, Japan ISAS Home Page |
For questions about this mission, please contact:
Dr. David R. Williams GSFC-Code 633 NASA Goddard Space Flight Center, Greenbelt, MD 20771 301-286-1258 david.r.williams@gsfc.nasa.gov |