Hayabusa on the Homestretch on Return to Earth

Hayabusa's sample return capsule descends under parachute toward the Woomera desert, Australia. Credit: Corby Waste and Tommy Thompson for NASA / JPL

After overcoming multiple serious glitches, and a three-year delay in its four billion miles (six billion kilometers) round-trip journey, JAXA’s Hayabusa spacecraft is expected to land in Australia around 14:00 UTC on Sunday, June 13; (midnight local time in Australia, 11 pm in Japan and 11:00 a.m. ET in the US). Scientists and space enthusiasts alike are hoping there is some precious cargo aboard in the sample return capsule: dust from an asteroid.

The latest word from JAXA, as of this writing, is that all systems were doing well on Hayabusa. The teams assessed the trajectory of Hayabusa and confirmed that everything was nominal.

If all goes well, Hayabusa will release a canister that will land in the Woomera Prohibited Area in the outback of South Australia; Hayabusa itself will follow, putting on a show over Australia as it breaks up and incinerates in Earth’s atmosphere.

You can follow the landing in several ways. A NASA team will be attempting to observe the re-entry of Hayabusa in a DC-8 plane, and they hope to have a webcast at this link.

There will be a “Hayabusa Live” website and a Hayabusa blog will be updated frequently, plus this Hayabusa Twitter feed.

Here’s a link to a finder chart and more from Paul Floyd at his website, Night Sky Online.

The Hayabusa spacecraft, formerly known as MUSES-C launched on May 9, 2003 and rendezvoused with the asteroid Itokawa in mid-September 2005. Hayabusa studied the asteroid’s shape, spin, topography, color, composition, density, and history. Then in November 2005, it attempted to land on the asteroid to collect samples but failed to do so. However, it is hoped that some dust swirled into the sampling chamber. You can listen to Universe Today writer Steve Nerlich (from Cheap Astronomy) tell the story of Hayabusa’s trials and tribulations on this 365 Days of Astronomy podcast.

The aim of the $200 million Hayabusa project was to learn more about asteroids and to help in our understanding of the origin and evolution of the solar system.

If Hayabusa is indeed carrying samples from the asteroid, it would be only the fourth sample return of space material in history — including the moon matter collected by the Apollo missions, comet matter by Stardust and solar matter in the Genesis mission.

We’re all hoping for the best for this first sample return from an asteroid, and it should be an interesting time in Australia. Dozens of scientists will be watching and waiting to see the return.

A view of Woomera from the Ghan train. Credit: Col Maybury

Plus, as Col Maybury from radio station 2NUR in Australia tells me, all traffic around the area will be stopped, including the Ghan train, one of the world’s great trains that travels from south to north across the continent of Australia, and it happens to be passing through Woomera right at the time Hayabusa should be returning. Col said he called the train company, and was told that the train engineers are to keep a look out for the entry trail.

“So a mighty train named after Afghan camel drivers may have to halt for a small spacecraft or be hit by a flying object,” Col wrote me in an email. He will have a live report on Radio 2NUR-FM on Tuesday the 15th at 10:20 am in Newcastle, 12:20 GMT, talking with the Woomera officials for a follow-up of the Hayabusa event.

Preliminary analysis of the samples will be carried out by the team in Japan, but after one year scientists around the world can apply for access to bits of the asteroid material for research.

Hayabusa May Come Home After All

Artist concept of the Hayabusa spacecraft, which visited asteroid Itokawa in 2005 and returned samples to Earth in 2010. Credit: JAXA
Artist concept of the Hayabusa spacecraft, which visited asteroid Itokawa in 2005 and returned samples to Earth in 2010. Credit: JAXA


As we reported last week, it seemed as if the Hayabusa asteroid explorer mission was dealt a fatal blow when the third of its four ion engines failed. But the Japanese Aerospace Exploration Agency (JAXA) announced yesterday that it may have come up with a solution to that problem to get Hayabusa back home by using components from two different inoperable thrusters in combination.

The Hayabusa mission has been rather plagued with problems throughout the entire mission. Its goal was to land on the asteroid Itokawa and return a sample to the Earth. It orbited the asteroid for three months in late 2005, and took near-infrared and X-ray spectral data. The landing, unfortunately, may or may not have gathered up a sample of the asteroid – though the container that the sample was supposed to go into may contain dust kicked up by the landing.

After taking off from the asteroid, communication was temporarily lost with the craft.  Communication was re-established with the craft, but the ion thrusters that propel it began to have problems, and as we reported last week, 3 of the 4 thrusters on Hayabusa were no longer operational. Thruster D, which has been the sole source of propulsion for the craft since February 2009, gave out due to a voltage spike. The remaining thruster, C, was shut down to avoid damage. Things were starting to look pretty grim for a mission that has overcome a lot of problems so far.

In an announcement made by JAXA yesterday, a solution has been proposed to use part of two different thrusters in combination to propel the craft. Ion engines work ionizing a neutral gas – in Hayabusa’s case, xenon – and forcing them out of an electrified grid on the back of the craft. When this is done, though, there is a negative charge imbalance in the craft which would attract the ions right back into the engines. To compensate, a neutralizer ejects electrons into the ionized gas that has been released, so that they don’t come back into the craft and the charge of the craft remains neutral.A diagram of how thrusters A and B will be joined to act as one thruster. Image Credit:JAXA

To fix the current problem, the JAXA engineers have proposed using the ion propellant from thruster B and the neutralizer from thruster A, effectively combining them into one complete thruster. Thruster A was deemed “unstable” after launch, and remains unused.

Thruster C will remain shut off, and only be used in case of failure of this rigged-up system. Its neutralizer is operating poorly, and given that the cause of failure for thrusters B and D was due to a neutrializer problem, the mission engineers want to be cautious.

Combining the engines will consume twice as much fuel and power as they would consume alone, but Hayabusa apparently has plenty of both in spades. 5 kg of fuel will be required to gain 200 meters per second acceleration over 2000 hours, but Hayabusa still has 20 kilograms of fuel in reserve. This system wasn’t tested on the ground, but apparently has worked in space for over one week (180 hours).

This thrusting combination will continue to propel the craft (barring further problems) until March 2010. If any other problems crop up, though, the team will have to delay the return of Hayabusa until 2013. If you want to see a cool – though somewhat cheesy – video of the Hayabusa mission so far, there’s a 30 minute one available on the mission site here.

Source: JAXA, The Planetary Society Blog

Hard-Luck Hayabusa In More Trouble

Artist concept of the Hayabusa spacecraft, which visited asteroid Itokawa in 2005 and returned samples to Earth in 2010. Credit: JAXA
Artist concept of the Hayabusa spacecraft, which visited asteroid Itokawa in 2005 and returned samples to Earth in 2010. Credit: JAXA

A problem-plagued Japanese mission to an asteroid just may have received its final blow. The Haybusa mission, which went to asteroid Itokawa in 2005 is currently trying to return to Earth, but now has suffered a breakdown in the third out of four ion thrusters. The cause was a voltage spike due to problems with a neutralization vessel, which previously caused the failure of two other thrusters. The fourth and only remaining thruster was shutdown earlier by engineers after signs that it also might succumb to high voltage damage. Engineers are now testing that engine, Thruster C, to determine if it is capable of long-duration firings. Hayabusa, which landed on Itokawa (possibly several times – mission managers aren’t sure) might contain samples, but due to a malfunction of the sample collection device, JAXA has acknowledged that it cannot be sure Hayabusa actually managed to take samples from the surface of the asteroid.

Thruster D failed last Wednesday, according to the Japan Aerospace Exploration Agency (JAXA).

Hayabusa’s four experimental microwave discharge ion engines consume xenon gas and expel the ionized propellant at high speeds to produce thrust. Ion engines are more efficient than conventional chemical thrusters because they use less fuel and can operate continuously for thousands of hours. Hayabusa’s thrusters have accumulated almost 40,000 hours of burn time since the probe launched in May 2003.

The spacecraft was originally scheduled to return to Earth in 2007, but the arrival date was pushed back to 2010 following thruster, communications, gyro and fuel-leak problems.

Thruster D had been the lone engine guiding the spacecraft since February 2009. Officials now say they are evaluating the asteroid mission’s return course after last week’s glitch, and will try to re-fire Thruster C in order to obtain the trajectory and speed required for the return to Earth.

Hayabusa spent three months exploring Itokawa in late 2005, taking over 1,600 pictures and collecting near-infrared and X-ray spectral data to investigate the small potato-shaped asteroid’s surface composition.

During a failed sampling attempt in November 2005, Hayabusa made an unplanned landing and spent up to a half-hour on Itokawa, becoming the first spacecraft to take off from an asteroid. The spacecraft attempted to fire a pellet into the asteroid’s surface and retrieve rock samples through a funnel leading to a collection chamber. However, telemetry showed Hayabusa likely did not fire its projectile while on the surface; but scientists were hopeful bits of dust or pebbles found their way through the funnel and into the sample retrieval system.

Source: Spaceflightnow