By Mark Williams
As China's star has risen, there's been speculation about whether its expanding space program will trigger a space race with the United States. After all, Shenzhou spacecraft have twice carried taikonauts to orbit and back, and they might in principle support the manned moon mission that the Chinese claim they'll carry out by 2026--and even, maybe, by 2017, one year before NASA now foresees a return to the lunar surface. Still, the next-generation CZ-5 Long March launchers necessary for a manned moon mission by China remain unfunded, and, in general, its space program has so far only repeated decades-old American and Russian achievements.
Meanwhile, attracting far less attention and operating on a far smaller budget, that other rising Asian giant, India, has also been ramping up its space program--and it is developing some novel, promising approaches. This spring, India's then president, A.P.J. Abdul Kalam--a colorful scientist-technologist who loomed large from the success of his country's early satellite launch missions, and then led its guided-missile program--laid out (via teleconferencing ) an ambitious vision of India's future space efforts during his speech at a Boston University symposium.
Kalam told the international audience of space experts in Boston that, besides expanding its extensive satellite program, India now plans lunar missions and a reusable launch vehicle (RLV) that takes an innovative approach using a scramjet "hyperplane." Kalam said that India understands that global civilization will deplete earthly fossil fuels in the 21st century. Hence, he said, a "space industrial revolution" will be necessary to exploit the high frontier's resources. Kalam predicted that India will construct giant solar collectors in orbit and on the moon, and will mine helium-3--an incredibly rare fuel on Earth, but one whose unique atomic structure makes power generation from nuclear fusion potentially feasible--from the lunar surface. India's scramjet RLV, Kalam asserted, will provide the "low-cost, fully reusable space transportation" that has previously "denied mankind the benefit of space solar-power stations in geostationary and other orbits."
Talk of grand futuristic projects comes cheap, of course. Nevertheless, the Indian Space Research Organisation (ISRO) performed its first commercial launch in April, lofting an Italian gamma-ray observatory into orbit on its Polar Satellite Launch Vehicle. Next, in early 2008, the Chandraayan-1, India's first lunar orbiter, will carry two NASA projects to search the moon's surface for sites suitable for the proposed U.S. Moon Base. And at next year's end, the first flight of the Hypersonic Technology Demonstrator Vehicle (HTDV), a demo for the scramjet RLV, is scheduled.
While this current spate of activity brings the country greater prominence, India's space program is hardly a new development. In 1975, ISRO launched its first satellite, Aryabhata, on a Soviet rocket, and in 1980, India's first home-built launcher, the SLV-3, successfully put a satellite into orbit. ISRO has continued with a series of larger satellites and rockets in the succeeding years. Rather than national prestige, the Indian focus has until recently been on entirely pragmatic applications that gave the most bang for its limited rupees: communications satellites to provide services to far-flung regions of a vast country with little existing communications infrastructure, meteorology packages (often carried on the same geosynchronous satellites that perform communications missions), and remote-sensing satellites to map India's natural resources.
Now ISRO is moving beyond that focus on immediately practical space applications. In November 2006, Virender Kumar, counselor for space at India's Washington, DC, embassy, told a forum on U.S.-India space relations at the Center for Strategic and International studies, "The time has come when you do have the feeling that you have accomplished a lot." Following much discussion within India's space-science community, Kumar continued, "They basically demanded that we go forward and do these exploration missions."
Setting aside the more science-fictional objectives described by President Kalam--whose term just ended, on July 25--in the near future, the most technologically innovative of ISRO's projects is its scramjet RLV, named Avatar. Lowering launch costs via an RLV has, of course, been theunattainable holy grail for both the United States and Russian space programs. Avatar would weigh only 25 metric tons, with 60 percent of that the liquid hydrogen needed to fuel the turbo-ramjet engines that would power its initial aircraft-style takeoff from an airstrip and its ascent to a cruising altitude. Thereafter, Avatar's scramjet propulsion system would cut in to accelerate it from Mach 4 to Mach 8, while an onboard system would collect air from which liquid oxygen would be separated. That liquid oxygen would then be used in Avatar's final flight phase, as its rocket engine burned the collected liquid oxygen and the remaining hydrogen to enter a 100-kilometer-high orbit. ISRO claims that Avatar's design would enable it to achieve at least a hundred reentries into the atmosphere. Theoretically, given ISRO's plans for it to carry a payload weighing up to one metric ton, Avatar could thus deliver a 500-to-1,000-kilogram payload into orbit for about $67 per kilogram.
Current launch prices range from about $4,300 per kilogram via a Russian Proton launch to about $40,000 per kilogram via a Pegasus launch. Conceivably, Avatar could give India a radical advantage in the global launch market. Gregory Benford, an astrophysicist at the University of California, Irvine, and an advisor to NASA and the White House Council on Space Policy, is enthusiastic: "The Avatar RLV project will enable the Indian program to leap ahead of the Chinese nostalgia trip. Once low cost to orbit comes alive, it will drive cheaper methods of doing all our unmanned activities in space."
Still, Avatar's potentially radical advantage comes with significant restraints, given both the restricted scale of its payloads and that very low 100-kilometer orbit. That latter factor, indeed, is something of a puzzle since any satellite released at such a height will find its orbit degrading quickly. Do the Indians intend to use Avatar as a first-stage launcher, in effect, from which they will fire their satellites further up into secure orbits? Perhaps. But in that case, it's hard not to notice that Avatar, in fact, makes more sense as a missile-launch platform. After all, the United States is also working on the scramjet concept but in the context of an unmanned global cruise missile: the X-51 Scramjet-Waverider.
Could Avatar be just another military application upon which India's space scientists are piggybacking their hopes to develop a radical RLV prototype? The Indians do seem to be serious enough about Avatar as a commercial concept that they've taken out patents internationally on the design. ISRO has, relatively, a very low budget, and for Avatar to happen, Indians need to bring in international partners and funding. But if it turns out that Avatar is really just another military application that India's space scientists have used to secure funding from their military for their high aspirations, they will hardly be the first ones in the history of spaceflight to do so.
http://www.technologyreview.com/Infotech/19115/