By the end of this month or in early January, India’s space agency is scheduled to launch a four-stage rocket to put satellites into low-Earth orbit for Indonesia and Argentina. This mission was also to include an Italian cartography satellite and the first test of the agency’s reentry and recovery technology. Next month India will test-launch a more powerful, three-stage rocket, designed to put much larger satellites into geosynchronous orbits. The third stage being introduced for this mission is of Indian design, rather than the Russian third stage previously used. Topping it all off, the year after next, India plans to launch a lunar probe, joining moon probes that China and Japan are readying for liftoffs in 2007.
All this activity testifies to a certain maturity that India’s space program has attained after several decades of steady effort and to the program’s growing international credibility and acceptance [see photo, "Liftoff"]. Its moon mission, Chandrayaan-I, will carry five instruments developed exclusively by the Indian Space Research Organization (ISRO) and six developed in whole or in part by foreign collaborators. Two were developed by NASA and one by the Bulgarian Academy of Sciences; three are duplicates of instruments that were on the European Space Agency’s SMART-1 lunar mission, which has just ended.
Having found itself with extra capacity of 25 to 30 kilograms aboard Chandrayaan-I, India invited space researchers around the world who wanted to include their instruments on the mission to apply for free rides. ”We selected instruments that would complement ours,” says G. Madhavan Nair, chairman of ISRO, in Bangalore.
NASA’s two instruments are the Mini Synthetic Aperture Radar, developed at Johns Hopkins University, in Baltimore, and the Moon Mineralogy Mapper (M3), jointly developed by NASA’s Jet Propulsion Laboratory, in Pasadena, Calif., and Brown University, in Providence, R.I. The former will search for ice deposits near the lunar poles, and the latter—an imaging spectrometer—will map the composition of minerals found on the moon’s surface. ”The moon has simply not been explored with instruments of such capabilities before,” says Brown’s Carle M. Pieters, principal investigator on M3.
At 590 kilograms, Chandrayaan-I will be larger than ESA’s 367-kg SMART-1 but smaller than Japan’s 1600-kg Selene lunar probe. The Indian probe relies heavily on proven technology. Its satellite configuration is derived closely from that of India’s meteorological satellite, Kalpana-1, and the rocket used for liftoff will be the Polar Satellite Launch Vehicle (PSLV), which has had eight successful launches in a row so far.
The PSLV, one of the two main workhorses in India’s space program, is a four-stage rocket: the first and third stages rely on a solid propellant, the second and fourth on liquid; solid propellant strap-ons provide extra thrust to the first stage. To be used in the late-November launch, the PSLV can lift satellites of 1000 to 1200 kg into polar, sun-synchronous orbits. It was developed by the Vikram Sarabhai Space Center, with support from the Liquid Propulsion Systems Center and the ISRO Inertial Systems Unit, all in Thiruvananthapuram, in the southernmost state of Kerala.
The Geosynchronous Satellite Launch Vehicle (GSLV), developed by the same organizations, is a three-stage rocket. The first stage burns solid fuel, but with four propellant strap-ons. The second stage uses hypergolic fuel (a combination of a liquid fuel and an oxidizer), while the third, cryogenic stage runs on liquid oxygen and hydrogen. It’s this third stage that, until now, has used a Russian engine, whose underlying technology the Russians would not share.
The GSLV had its first operational launch in September 2004, when it carried EDUSAT, an Indian satellite dedicated to distance learning. In its Mark III version, scheduled for testing in 2008, the GSLV will be able to launch 4â''metricâ''ton satellites into geosynchronous orbits or 10-metric-ton satellites into low-Earth orbits.
Last July ISRO had a setback when the GSLV, in its fourth and final flight still using a Russian engine, came down in flames soon after the liftoff. But in less than a month, the space agency was able to pinpoint the fault, which was a manufacturing defect in a pressure regulator in one of the four strapâ''on engines. Much will be riding on next month’s test launch, as perceived reliability obviously will be crucial to India’s breaking into the commercial launch market for the 2â''metric-ton class of satellites.
Planning for global business, however, occupies only 20 percent of ISRO’s time and resources. Its calendar is pretty full from burgeoning domestic demand. In July 2006, it announced it will set up the Indian Regional Navigation Satellite System (IRNSS), similar in principle to the U.S. Global Positioning System.
To be implemented over six years, IRNSS is designed to give a location estimate accurate to 130 meters for normal applications—about the same as GPS—and to 10 meters for critical applications. Not wanting to rely on foreign assistance for IRNSS, the space agency is wooing local industry. ”More than 400 companies are already involved in the Indian space program, but with IRNSS, there is scope for many more to enter,” says K.R. Sridhara Murthi, executive director of Antrix Corp., ISRO’s commercial wing.
Meanwhile, ISRO and Airports Authority of India are already implementing a satellite-based navigation system over Indian airspace for civil aviation, called GAGAN (GPS-Aided Geo-Augmented Navigation). The space segment of GAGAN is in the form of a dual-frequency, GPS-compatible payload that will be flown on India’s GSAT-4 satellite, to be lifted by a GSLV rocket in 2007.