© 2005 Nature Publishing Group

Hayabusa ready to head home with asteroid sample

Space scientists in Europe are pleading withministers to significantly boost the EuropeanSpace Agency’s (ESA’s) science programmewhen they meet to decide its budget for thenext five years. Without such an increase, researchers fear that high-profile missionsmay have to be abandoned.

“We are struggling to keep control of thebudget,” says Marcello Coradini, coordinatorof Solar System Missions at ESA headquartersin Paris. Costs of science missions in develop-ment are predicted to exceed available moneyby €300 million (US$350 million) to €400million over the coming decade.

If money allocated by ESA’s ministerialcouncil, which meets in Berlin on 5–6December, does not alleviate the pressure onthe programme’s finances, scientists say it may not be possible to cut back missions

without undermining their scientific goals.And agency officials say they may be reluctantto absorb the costs — roughly equivalent toone year of spending — through delays,because that means no new missions can be started.

The situation has led to speculation thatBepiColombo, a mission destined for a 2013launch to Mercury, might be cancelled. “Thatis the big danger painted in the sky,” says Karl-Heinz Glassmeier, principal investigatoron one of the instruments proposed for the spacecraft.

Nerves were set jangling about the project,which also involves the Japan AerospaceExploration Agency, after it was postponedbecause the initial design was too heavy. Thatproblem seems to have been solved, but offi-cials say the estimated cost of the mission, at

€600 million to €650 million, is still morethan €100 million above target.

Researchers on BepiColombo are not theonly ones worried. “We’re all biting our nails,”

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TOKYOJapan’s latest space mission seemsto have succeeded in its secondattempt to collect pieces of a smallasteroid. If so, this will be the firsttime a sample has been collectedfor return to Earth from any objectin the Solar System apart from theMoon. However, engine troublecasts doubts on whether the craftcan return home safely.

On 25 November, the JapanAerospace Exploration Agency(JAXA) said data sent fromHayabusa show that all stages of thesampling process went well. Agencyengineers said it was almost certainthat Hayabusa’s sampler hadtouched down on the Itokawaasteroid as planned, and shot twometal pellets into the rock to throw upfragments of the surface. “I think wecollected a sample,” said projectmanager Jun’ichiro Kawaguchi.

Hayabusa was launched in May2003, and arrived this September atItokawa — a potato-shaped, 540-metre-long asteroid located about300 million kilometres from Earth.

Hayabusa is expectedto leave Itokawa byearly December for its return journey.Whether a sample wasdefinitely collected willnot be known until thecraft reaches Earth inthe summer of 2007.

To reach this stage,the members of theHayabusa team haveendured a rough time.Two of the craft’s threereaction wheels, which stabilize theprobe and help navigation, stoppedworking; the first failed in July andthe second in October. Chemicalengines on board were used instead.But their lower accuracy madelanding more difficult. In the firstlanding attempt, on 20 November,Hayabusa seemed to park on theasteroid’s hot surface for more than 30 minutes, and failed to collect a sample.

Time and fuel were runningshort, so the 25 November try wasalmost the last chance to collect a

sample. “It was learning in realtime,” says Donald Yeomans, US project scientist for Hayabusaand senior research scientist atNASA’s Jet Propulsion Laboratoryin Pasadena, California. With eachattempt, he says, “they learnedmore and more about how thespacecraft behaves”.

Still, concerns remain. Hayabusalost its balance soon after departingfrom the asteroid. Engineers areinvestigating the cause, but onepossibility is that the craft’s long stayon Itokawa’s hot surface during the

first landing attempt damaged oneor more of its 12 chemical engines.JAXA said that if the trouble couldnot be fixed, it would be difficult forHayabusa to return to Earth.

But astronomers have praisedHayabusa’s achievements so far asshowing the way for future asteroidmissions — especially thoseinvolving the operation of ion-propulsion engines and delivery ofhigh-resolution images. Analysingthe sample, assuming it makes itback to Earth, would also help toanswer questions about how theSolar System was created.

The mission is renewing Japan’sconfidence in space activities.JAXA has recently tried a string ofhigh-risk missions, but has seenmany failures over the past fewyears. “Hayabusa’s success hasbecome a tailwind for Japan’s spacedevelopment,” Hajime Inoue,JAXA’s executive director, said at apress conference. “It proves thatthe way we have been doing thingswasn’t wrong.” ■

Ichiko Fuyuno

Hayabusa snaps its own shadow as it descends.

ESA scientists areconcerned thatBepiColombo may be cancelled.

ESA

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