Hayabusa

Hayabusa (Japanese小惑星探查机「はやぶさ」 ( MUSES -C), shōwakusei tansaki " Hayabusa " ( Muses -C), dt " asteroid probe, Peregrine Falcon ' ( Muses -C) " called before the start of " Muses -C " ) was a spacecraft of the Japanese space agency JAXA that the asteroid ( 25143 ) Itokawa was launched on 9 May 2003. On 12 September 2005, the probe reached its destination, and took soil samples there. After a return flight, which was delayed due to various technical problems for three years, came the return capsule separated with the sample and the probe on June 13, 2010 from 13:56 UTC ( 23:30 local time clock ) over Australia in the earth's atmosphere. It was the first returned from the surface of an asteroid with a spacecraft sample.

Mission

Hayabusa met in September 2005 when asteroid ( 25143 ) Itokawa (formerly 1998 SF36 ) a. The originally planned arrival date was June 2005, but some of the solar cells of the probe were damaged due to larger solar storms, so that the ion engines were less power and thus could provide less thrust. The probe was the first Japanese spacecraft with ion thrusters. A swinging into orbit around the asteroid was not planned. The probe remained instead in a position in the vicinity of the asteroids. After mapping from altitude of 20 km the probe approached the asteroid several times. Whether this attempted removal of about one gram of soil material was successful, was initially uncertain. Nevertheless, the probe took the sample container back to Earth. For sampling Hayabusa had a funnel-shaped opening, which served as a dust catcher. Wherein the ground contact of the funnel, a small bullet was fired onto the surface and the sample container is opened for a short time. A part of the fluidized material should be collected in this way. In addition, shortly before the actual ground contact is a so-called target marker was exposed on the surface, the space probe used for navigation. He also contributed in 30 nanometers large font 880,000 names, which could be transmitted via the Internet to the 2002 JAXA. The return to Earth was delayed due to various problems with the position control, the Hydrazintriebwerken and data transfer. Therefore, the first possible start date back, early December 2005 could not be used. In the ground- technically return next opportunity in April 2007, the probe was able to compete with its ion propulsion the return trip to Earth, which we achieved on 13 June 2010, where the return capsule was separated and landed in Australia.

Originally, the mission was to take place with the involvement of the United States who wanted to contribute a little Nano Rover called Muses -CN. The rover was canceled for financial reasons. For Hayabusa led with a small, only 591 g heavy Japanese lander named Minerva ( abbreviation of Micro / Nano Experimental Robot Vehicle for Asteroid ), which is equipped with three cameras and solar cells. The lander should be discontinued at the first sampling attempt on the surface, where it should by the very low gravity of the asteroid on " bounce " while shooting pictures. As has been suspended due to a timing error, the probe while Hayabusa was located away after a successful approach to the surface already back in an upward motion of the asteroid, crossed Minerva which to overcome the gravity of the asteroid necessary escape velocity and went about 14 hours radio contact in space lost.

Course

Hayabusa was launched on 9 May 2003 by the Japanese successfully Uchinoura Space Center in Kagoshima on a MV rocket.
The end of 2003 came the probe into strong solar winds, which damaged the solar panels and led to a three-month delay in arrival due to the lower thrust of the ion engines.
On 19 May 2004 Hayabusa resulted from a swing-by maneuver on the ground. The flyby altitude was 3700 km.
Went 31 July 2005 at a (X -axis) of three necessary for position and orientation control gyroscopes aboard the spacecraft out of service.
On August 14, 2005 Hayabusas first image of Itokawa was released. The photo was taken by a star tracker and showed a moving point of light that was held for the asteroid. More pictures were taken between 22 August and 24 August.
On 28 August 2005, the ion engines were shut down to position correction purposes now chemical engines were used.
On 12 September 2005 Hayabusa reached a position away about 20 km from Itokawa, in which the space probe "persisted ". This position has been designated by the JAXA as " gate position ". The chemical thrusters fired at 1:17 UTC the last time, to compensate for the relative velocity of the probe and the asteroid. Now Hayabusa was in orbit, which was almost equal to the orbit of the minor planet - the difference in speed is 0.25 mm / s
30 September 2005 Hayabusa moved with the help of its chemical thrusters in the "Home Position" that was removed about 7 km from the asteroid.
On 2 October 2005, the second (Y- axis ) of the three gyroscopes failed. From now on, the attitude control with the leftover gyroscope (Z- axis ) and two chemical engines was performed.
On 2 November 2005, JAXA held a press conference, during which the first high-resolution images were presented by Itokawa. The proposed surface locations of sample collection were shown and mentioned the dates for the extraction experiments.
On November 4, the first sample approach was canceled after the asteroid.
On November 12, the lander Minerva was exposed at an altitude of about 200 m at the second sample approach. The exposure was carried out while the mother spacecraft was in an upward motion so that Minerva was lost in space. During this trial approach a target marker also was suspended.
The first sampling was launched on 19 November. A target marker was suspended at 19:55 UTC clock at a height of 40 meters and reached about 6.5 minutes later the asteroid's surface. Then the probe followed the target marker in the fully automatic mode at a rate of about 2-3 cm / s, at a height of 17 meters put scheduled communication with the Earth, because at this time, contact with the probe from a ground station one was handed over to others. After the first reports of the approach were nominal up to a height of about ten meters, after which the probe went into a safe mode and began to rotate slowly. As a possible cause was the overheating of the electronics of the probe near the sunlit surface having a temperature of about 100 ° C, called. When the contact is restored Hayabusa sent to the probe away from the surface. Hayabusa away then to an altitude of about 100 km from Itokawa. However, after the data stored on board the spacecraft data were downloaded and analyzed, it was found that Hayabusa was apparently actually landed on the asteroid and had stayed there about 30 minutes. Since the landing had not taken place in a scheduled mode, no samples were probably taken.
The second landing took place on 26 November 2005. This time, the mechanism of sampling performed flawlessly after the first reports. Whether material was removed, is not yet certain, however, is assumed for the JAXA of a successful sampling. In addition, there were problems with one of the attitude control thrusters, possibly a fuel leak is there caused by the contact with the asteroid surface. In order to stop the loss of fuel, Hayabusa was initially transferred into the safe mode.
Due to lack of connection to the probe and the discharge of the batteries, the start window on 14 December 2005 was not used. Whether successful samples were taken, was still unclear.
On 23 January 2006, JAXA received the first, nor unmodulated signal of Hayabusa since early December 2005. During the next weeks, the probe was brought under control and established a stable communication.
On 25 April 2007 Hayabusa performed with the help of its ion engines on the way back to Earth, which predicts how at this point was reached in 2010. Whether the probe would survive this unplanned long flight, the time was unclear.
The engines have been shut down, on 24 October 2007 and aligning the probe with the axis of rotation to the sun. She flew from now on listless on a Hohmann path towards Earth's orbit. The engines were until then 31,000 hours in operation and still had enough thrust and enough fuel. The orbit maneuver was continued until February 2009.
In May 2008, the return capsule was checked one last time for functionality and finally sealed. On 2 June 2008, Hayabusa 1.5 AE was removed from the sun and seen from Earth, behind the sun.
On 4 February 2009, JAXA announced the successful ignition of the engines. By March 2010, the probe should be further accelerated the return was scheduled for June 2010.
On 4 November 2009, it was found that D had engine switched off automatically due to problems. It was not possible to activate the engine again. Also engine C was meanwhile shut down, but functional.

During the return flight found from May 4, 2010 (distance to Earth: 16.6 million km ) of four trajectory correction maneuvers in order to coordinate the path of the probe on the ground and the landing site.
Despite numerous failures of components (eg, were two gyroscopes disabled, only four of the eleven lithium -ion batteries functional, the chemical fuel was used up and the antenna pointing mechanism blocks ) was the spacecraft will be returned to Earth and was dismissed on 13 June. , 2010 at 10:51 UTC of 20 kg re-entry capsule with the sample. The probe burned up about South Australia and was able to be pursued by several monitoring stations, while the return capsule landed as scheduled at the parachute in the Australian Woomera Prohibited Area and was located an hour later by helicopter. Here the apparently intact capsule was recovered the next day and sealed till the examination of the samples.
Due to the success of the mission JAXA agreed in autumn 2010 for a successor mission Hayabusa 2, which start in 2014 and to visit the asteroid 1999 JU3.

Data

Take off weight: 510 kg, of which: Empty mass: 380 kg
Fuel: 60 kg xenon 70 kg of chemical fuel

AMICA - multi-band camera
LIDAR - Laser rangefinders
NIRS - spectrometer in the near-infrared region
ONC -W - wide-angle camera
XRS - X-ray spectrometer

Results

The recordings of the probe has reached Itokawa in September 2005, show the asteroid's surface with a resolution of less than one meter. What is striking is the almost complete absence of impact craters dominate the surfaces of other asteroids that have been explored by spacecraft, such as (243 ) Ida or ( 433 ) Eros. Some areas on Itokawa is covered by regolith and rocks of various sizes, elsewhere apparently is bare rock free. The average density of Itokawa could be determined by Hayabusa 2.3 ± 0.3 g / cm ³. This is somewhat less than would have been expected for compact silicate rock. These observations suggest that it is the asteroid to a held together only by the force of gravity, porous " rubble pile " (English rubble pile ) is.

After notification of JAXA, the return vessel which was carefully examined under high-purity conditions contained a number of small particles, which were examined in the sequence. The investigations showed that the particles definitely come from Itokawa.

The follow-up mission Hayabusa 2 in 2014 or 2015 start with a H-IIA rocket. As a target, the asteroid 1999 JU3 is under discussion. Hayabusa 2 could reach him in 2018 to investigate him a year and bring a soil sample in December 2020 back to Earth.

Other missions to asteroids

Galileo Gaspra in 1991 and 1993 with Ida
NEAR Mathilde in 1997 and 2000 to 2001 in Eros
Deep Space 1 in 1999 Braille
Stardust 2002, Anne Frank and 2004 Wild 2
Dawn to Ceres (arrival in February 2015 ) and Vesta (arrival August 2011), launched on September 27, 2007.
Rosetta flyby of Šteins on 5 September 2008.
Rosetta flyby of Lutetia on 10 July 2010.

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