Fueling trust in rocket science
(From The Japan Times Feb. 28 issue)

日本の宇宙開発事業の課題

    On Jan. 24, the H-IIA No. 8 rocket lifted off from the Tanegashima Space Center in Kagoshima Prefecture and placed the Advanced Land Observing Satellite, nicknamed Daichi (Earth), into orbit. This was followed by the Feb. 18 launch, from the same space center, of the H-IIA No. 9 rocket, which sent the Multifunctional Transport Satellite 2 for weather observation and air traffic control into orbit.

    Most recently, on Feb. 22, an M-V No. 8 rocket blasted off from the Uchinoura Space Center, also in Kagoshima, at 6:28 a.m. Two hours later, it was confirmed that the ASTRO-F satellite for infrared astronomical observation had entered orbit, with its solar cell panel spread.

    Although JAXA suffered a long blank period following the H-IIA No. 6 rocket's launch failure in 2003, it has been doing well since launches resumed in February 2005.

    ASTRO-F, nicknamed Akari (Light) and shaped like a cylinder, travels in an orbit that passes over the North and South Poles at an altitude of 745 km. Equipped with a 68.5-cm-aperture telescope cooled with liquid helium, and circling the Earth above the twilight zone, the satellite will make an all-sky survey in the wavelength range of 1.7 microns (near-infrared) to 180 microns (far-infrared).

    Infrared observation makes it possible to see stars that are so far away, or whose temperature is so low, that they are otherwise invisible. The satellite will discover millions of new celestial bodies, including those more than 13 billion light years away, and make a detailed "map" of the known universe with 10 times more sensitivity than existed with the first such map made by Infrared Astronomical Satellite, jointly launched in 1983 by Britain, the United States and the Netherlands.

    ASTRO-F's telescope is cooled to minus 267 C by liquid helium to suppress its thermal radiation, which hinders observation. The satellite, which cost about ¥13.4 billion to develop, will be in operation as long as the liquid helium lasts — about 550 days.

    ASTRO-F's scientific mission includes detecting more than 10 million newborn galaxies, investigating their origin and evolution, observing the formation of new stars and the death of old stars, and searching for planetary systems outside the solar system.

    JAXA's mission schedule has tightened following the successful ASTRO-F launch. In fiscal 2006, starting April 1, three H-IIA rockets are to carry two data-collection satellites and one satellite to test telecommunications technology, and an M-V rocket is to launch a solar observation satellite.

    JAXA was established in October 2003 through a merger of the National Space Development Agency of Japan, the Institute of Space and Astronautical Science and the National Aerospace Laboratory of Japan. A month later, though, the launch of the H-IIA No. 6 rocket carrying a data-gathering satellite failed because solid fuel boosters did not separate from the main rocket after liftoff. As a result of that failure, there were no launches — either of Japan's mainstay H-IIA rockets developed by NASDA or of the ISAS-developed M-Vs (for delivering scientific research satellites) — in 2004.

    Since the successful launch of the H-IIA No. 7 rocket in February 2005, JAXA has launched two M-V rockets. As far as the H-IIA rockets are concerned, JAXA has been successful in eight of nine launches, for a success rate of 89 percent. This approaches the 90 percent to 94 percent success rate of mainstay rockets launched overseas. JAXA hopes that H-IIA rockets will become competitive enough in the eyes of the international market — dominated by the United States, the European Union, Russia and China — to place commercial satellites into orbit.

    It will take a longer series of successful rocket launches to impress potential customers with JAXA's reliability. Even with that, JAXA's path to viability in the global rocket business won't be easy. One problem is cost, which is 20 percent to 30 percent higher for JAXA rockets than for those of overseas competitors.

    Following the Feb. 22 launch, Mr. Keiji Tachikawa, head of JAXA, said the feat may help put Japan's space program in a stable orbit. He added that to establish a solid reputation in world competition, JAXA probably needs to launch rockets and satellites about 20 times without a failure. And it needs to show more concrete results in the placement of commercial and scientific research satellites.

The Japan Times Weekly
March 4, 2006
(C) All rights reserved

    JAXAは1月24日に陸域観測技術衛星を搭載したH2Aロケット8号機と、2月18日に運輸多目的衛星2号機を載せたH2A・9号機を、それぞれ種子島宇宙センターから打ち上げた。さらに2月22日、赤外線天文衛星ASTRO-Fを載せたM-Vロケット8号機を内之浦宇宙空間観測所から打ち上げた。

    ASTRO-F「あかり」は、北極、南極上空745キロの太陽同期軌道より1.7ミクロンの近・中間赤外線から180ミクロンの遠赤外線までカバーする口径68.5センチの望遠鏡で全天観測を行う。

    ASTRO-Fのミッションは、1000万以上あるといわれる新生銀河の調査、銀河の形成と進化過程の解明、新星の形成と旧星の消滅の観測、太陽系外の惑星系の探索などである。JAXAは06年度に3機のH2Aによってデータ収集衛星2機と通信技術試験衛星1機を、M-V 1機で天体観測衛星1機を打ち上げる予定だ。

    JAXAは03年10月に宇宙開発事業団、宇宙科学研究所、航空宇宙技術研究所が合併して設立された。1ヵ月後H2A・6号機の打ち上げに失敗、打ち上げを一時停止したが、05年2月にH2A・7号機、その後M5、2機の打ち上げに成功した。H2Aについては9機のうち8機の打ち上げに成功している。

    JAXAは、現在米国、EU、ロシア、中国が優位を占める商業衛星打ち上げ国際市場への進出をねらっている。ただ、JAXAがロケット打ち上げ成功率を高めても、そのコストは外国に比べ20%〜30%高いのが問題だ。

    JAXAの立川敬二理事長は、日本が世界の宇宙開発市場で競争するには、ロケット・衛星に打ち上げに20回連続で成功する必要があると述べている。商業衛星、科学衛星打ち上げに、より具体的成果を示さねばならない。