[Editor’s Note: After a delay of more than a week, India's Chandrayaan-2 lunar probe successfully lifted off on July 22 at 5:13 a.m. EDT (2:43 p.m. local Indian time.]
A week after its launch was postponed, India’s uncrewed Chandrayaan-2 spacecraft is set to roar skyward in the early afternoon of July 22. It will take off from the Indian Space Research Organization’s (ISRO’s) Satish Dhawan Space Center, a facility on the barrier island of Sriharikota, off the coast of the eastern state of Andhra Pradesh. Riding atop the nation’s most powerful rocket, the spacecraft is India’s most ambitious mission of its kind yet: In September it is due to attempt a historic touchdown near the moon’s south pole, where water ice lurks in permanently shadowed craters. Only one other mission—China’s Chang’e-4 spacecraft—has soft-landed in the vicinity of this rugged, forbidding region.
Chandrayaan-2 is composed of three modules: the orbiter, the Vikram lander (named after Vikram Sarabhai, the late father of India’s space program) and the Pragyan rover (named after the Sanskrit word for wisdom). Costing about $144 million, the mission’s significance is both national and global. With any luck it will mark India’s first soft-landing on another world, bringing the nation into an exclusive club of which the U.S., the former Soviet Union, Europe, China and Japan are now the only members. (Chandrayaan-2’s predecessor, the Chandrayaan-1 spacecraft, deliberately crashed a probe into an ice-filled crater at the lunar south pole in 2008.) The new mission’s journey could yield vital information about the moon’s mysterious troves of water, which could be used for scientific studies of deep lunar history—or for manufacturing rocket fuel, potable water and breathable air in support of future human outposts.
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“Chandrayaan-2 is India’s Sputnik moment, a giant leap in India’s scientific and technological progress,” says Goverdhan Mehta, a member of the nation’s Space Commission. “The success of the mission is going to boost national morale and contribute to [India’s] scientific endeavors in ways ranging from academic research to national security. The mission is completely indigenous, with heavy participation from the private sector and academia, involving young scientists from across the country—a reflection of India’s rising scientific temper.”
“In addition to confirming data obtained from the Chandrayaan-1 mission and demonstrating ISRO’s advanced space capabilities, [Chandrayaan-2] is exploring habitat-building conditions and the presence of [resources] for future longer-duration lunar missions,” says G. Madhavan Nair, former head of ISRO and chief architect of Chandrayaan-1. The mission will also serve as a proof of principle, demonstrating that India possesses the technical prowess not only to land on the moon but also to remotely operate a robotic rover there. More broadly, it represents the latest example of the nation’s ambitious space projects, which also include its first mission to Mars in 2013 and a planned human space launch as early as 2022. This year alone, the Indian government has increased the annual budget for its space program more than 15.6 percent, to about $1.6 billion.
The orbiter, lander and rover will collectively carry 14 scientific payloads, including a Laser Retroreflector Array from NASA to provide precision measurements of the distance between Earth and the moon. From orbit, instruments will create detailed three-dimensional maps of the surface, both to ascertain the safety of potential landing sites and to track the distributions of water molecules, hydrated minerals and other materials of interest on and around the moon. If touchdown is successful, the Vikram lander will serve as a listening station for seismic waves from moonquakes, which could reveal more details about the structure of the lunar core, mantle and crust. Further studies are set to take place via the Pragyan rover, which is meant to drill into the surface to gather samples for additional mineralogical and chemical analysis.
After launch, Chandrayaan-2 will initially reside in a highly elliptical, temporary “parking” orbit, with its lowest point just 170 kilometers above Earth and its highest point more than 40,000 kilometers overhead. From there, a series of rocket-engine burns will push the outermost edge of the spacecraft’s orbit to even greater distances, finally allowing Chandrayaan-2 to be captured by the moon’s gravity. Then further maneuvers will place the spacecraft into a circular orbit 100 kilometers over the lunar surface in early September. Following the separation of the Vikram lander from the orbiter, the lander will set out for a target site situated between the south-polar craters Manzinus C and Simpelius N.
K. Sivan, ISRO’s current chairman, describes the challenging soft landing as a “terrifying 15 minutes.” Finally, if all goes well, the Pragyan rover will roll onto the lunar surface at an average speed of one centimeter per second to traverse a distance of 500 meters. The Chandrayaan-2 orbiter is planned to operate around the moon for a full year, conducting scientific reconnaissance and also serving as a communications relay. Down on the surface, the lander and rover alike are intended to survive for just one lunar day, which is equivalent to 14 Earth days.
Although it may seem that ISRO has deliberately timed Chandrayaan-2’s launch to closely coincide with the 50th anniversary celebrations of the first human lunar landing, which will occur on July 20, the proximity is the result of chance alone. Originally intended to launch several years ago, Chandrayaan-2 was repeatedly delayed, in large part because of Russia’s withdrawal as a partner on the mission—a development that forced India to build the lander Russia failed to deliver. In coming years, the Chandrayaan-2 lander and rover are destined to be joined at the lunar south pole by a burgeoning fleet of new exploratory craft from other nations, including the U.S. and China and perhaps countries from Europe—as well as those built, launched and operated by private-sector initiatives. Soon everyone on Earth will look up at an increasingly crowded moon.