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Asteroid Probe, Rocket Get Nod from Japanese Panel

Theboard governing Japan's space programlast week formally approved a successor to the Hayabusa asteroidexplorer andthe Epsilon small satellite launch vehicle to continue development.

TheSpace Activities Commission decisiongives the Japanese government authority to request funding for theprograms inits budget for the next fiscal year, which begins in April.

Thegovernment space panel, which hasoversight of the Japan Aerospace Exploration Agency, only gave thego-ahead forpreliminary design work on Hayabusa2,a mission projectedto cost nearly $200 million.

Thecommission recommended proceeding with fulldevelopment ofthe Epsilon rocket,a new Japanese launcher to send small satellites into orbit beginningin 2013.

TheHayabusa 2 mission would blast off assoon as 2014 and reach a carbon-rich asteroid in 2018 for atouch-and-goapproach to collect samples. After spending a few months in thevicinity of theasteroid, the probe would return to Earth in 2020.

Thespacecraft's mission would replicate thefeat accomplished by Hayabusa, the mission that completed the firstround-tripjourney to an asteroid in June. During its seven-year journey to andfromasteroid Itokawa, Hayabusa suffered major glitches in its samplecollectiondevice, propulsion system and reaction wheels. [Graphic:How Japan'sHayabusa Asteroid Mission Worked]

Butthe probe released an entry capsule thatlanded in Australia, possibly with the first microscopic dust grainsfrom thesurface of an asteroid.

Hayabusa2 would incorporate improvements tothe faulty systems that plagued its predecessor, but the craft wouldrely onthe same fundamental design to slash costs.

JunichiroKawaguchi, Hayabusa's projectmanager, said a "good indication was shown by the government" innegotiations and hearings over the past few weeks.

"Preciselyspeaking, still we need some moretime to make it actually appropriated. But most opinions say themission shallbe performed," Kawaguchi wrote in an e-mail to Spaceflight Now.

Kawaguchiis managing the Hayabusa 2 proposalteam, but he will relinquish leadership once the mission enters fulldevelopment.

Hayabusa2 would target an asteroid named1999 JU3, a C-type body with a diameter of about 1 kilometer, or 0.6miles.Scientists say C-type asteroids are the unspoiled relics of the earlysolarsystem, which was dominated by small bodies as the planets coalesced.

Itokawa,the destinationforHayabusa,is a stony rubble pile asteroid that formed from separate objectsfusingtogether over time.

Japanis moving forward with Hayabusa 2 afterthe Marco Polo mission, a joint asteroid probe with Europe, was notselected byan international panel of scientific advisors earlier this year.

Thebudget decisionsfor JAXA are being considered as an economic stimulus, according toKawaguchi.

YasuhiroMorita, the Epsilon rocket's projectmanager, said the new launch vehicle will be ready for servicebeginning in2013. It will replace the M-5 rocket, a similar vehicle that flew seventimesbetween 1997 and 2006.

"We'vealready spent three years on thepreliminary design," Morita said. "This is the actual start of thedevelopment. This is a good time for us."

Nowfinished with preliminary development,engineers are focusing on a critical design review planned about 18months fromnow.

TheEpsilon rocket will launch about once peryear with small technology demonstration and scientific missions,starting witha craft named Sprint-A that will place a telescope into a 300-mile-highEarthorbit to observe Venus, Mars and Jupiter.

Thethree-stage launcher is designed to liftmore than 2,600 pounds to low Earth orbit. The M-5 rocket could haulabout4,000 pounds to a similar trajectory.

Morita,who is also the former manager of theM-5rocket program,said it will costapproximately $200 million to finish developing the Epsilon rocket, butit'smuch less expensive than the M-5, which carried a $70 million price foreachlaunch. He would not discuss the Epsilon's cost per flight.

"Forexample, the M-5 first stage rocketmotor was very expensive because it uses a big chamber and is in twosegments.We had to assemble the two segments at the launch site," Morita said.

Engineerswill also design the Epsilon withmore autonomy, making the rocket less labor-intensive and reducing theworkforce required for launches.

"Thelaunching performance of the M-5was the best in the world for a solid rocket at the time, butoperations took alot of time and labor," Morita said in an interview with SpaceflightNow."As far as the Epsilon rocket, the sales point is its responsiveness.Thisis far beyond the M-5's capacity, so we can extend the solid rockettechnologyin Japan, not only in the launching capacity but also in operations."

JAXA'sgoal is to have an inexpensive rocketready to answer the needs of scientists and engineers building low-costsatellites.

Epsilondesigners are reusing technology fromthe M-5 and H-2A rockets to cut costs. The Epsilon's first stage isbased onthe H-2A's solid rocket booster, while the second and third stages willuseheritage solid-fueled motors from the M-5's upper stages.

Accordingto Morita, JAXA has still notdecided where to launch the new rocket.

Itcould be operated from the Uchinoura SpaceCenter on the south shore of Kyushu, the southernmost of Japan's mainislands.The M-5 rocket's launch pad at Uchinoura could be modified to supportEpsilonlaunches, Morita said.

Anotheroption is Japan's main launching baseat the Tanegashima Space Center, the home of the much larger H-2A andH-2Brockets. One of two active launch pads there could be outfitted for theEpsilonrocket, or a vacant Tanegashima launch pad used by the N-1 and N-2rockets morethan 20 years ago could also host Epsilon missions, according toMorita.

"Oneof the most remarkable features ofthe Epsilon rocket is its mobility, so the vehicle can be launched byUchinouraas well as by Tanegashima, and the government has not yet decided itslaunchsite," Morita said.

Moritasaid high construction costs mightlimit the Epsilon to just one launch site.

IHIAerospace Co. is the Epsilon rocket'sprime contractor. The company builds the H-2A solid rocket boosters andpreviously held the lead contract for the M-5 rocket.

"Thesmall rocket will be required forsmall satellite missions," Morita said. "The H-2A is too big tosupport small satellites. We need a small launcher with theresponsiveness tosupport small satellites."

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Stephen Clark

Stephen Clark is the Editor of Spaceflight Now, a web-based publication dedicated to covering rocket launches, human spaceflight and exploration. He joined the Spaceflight Now team in 2009 and previously wrote as a senior reporter with the Daily Texan. You can follow Stephen's latest project at (opens in new tab) and on Twitter (opens in new tab).