In the early 1970s, Vikram Sarabhai had asked a bunch of young engineers, fresh out of college, to make a satellite in just two and a half years. Their offices were unremarkable: six asbestos sheds in Peenya, then a new industrial township off the city of Bangalore. No one thought it was possible to build satellites so quickly, except for the engineers at the Indian Space Research Organisation (ISRO) and their leader UR Rao. The satellite went up on time from a Soviet cosmodrome. It had payloads on x-ray astronomy, then an emerging subject in science.
This satellite, Aryabhatta, was ISRO’s first satellite. Sarabhai and UR Rao were cosmic ray physicists and were keen on using space technology for scientific research. As ISRO learned to make more complex satellites, ISRO began focusing on communication and remote sensing, on societal needs than scientific research. Scientific research shrank to become a small unit in the organization.
Science never left the organisation fully, and scientific programmes started growing more than a decade ago. In the last five years, it has made a vigorous comeback in ISRO through planetary exploration and astronomy missions. “Future generations will depend on planetary missions,” said ISRO chairman K Sivan at a press conference on Wednesday.
Next month, on July 15 or 16, ISRO’s Chandrayaan 2 spacecraft will lift off from Sriharikota on a 52-day trip to the moon. After it lands near the south pole of the moon, it will do mineral and water prospecting on the earth’s natural satellite. After the moon mission, ISRO is planning a series of increasingly sophisticated interplanetary missions: to the Sun, to Venus, another trip to Mars, and a third trip to the moon. As part of these missions, ISRO will also develop strategic technology that are critical in the twenty-first century. “The difference between science missions and other satellites is like the difference between an ordinary submarine and deepsea exploration,” says assistant professor at IIT Bombay, who is developing instrumentation for future astronomy missions. “Science requires you to push the boundaries.”
The current moon mission is testing out some technologies for the first time, the most critical of which is the ability to soft-land on the moon. Only three countries have landed softly on the moon: Soviet Union, United States, and China. Soviet Union was the first to land on the moon, in 1966. Although this landing was done more than five decades ago, descending and landing softly on the moon is still a technically challenging task. “These 15 minutes are the most terrifying moments of the mission,” said Sivan.
Soft-landing is a tricky business for several reasons. One, the acceptability of failure is very low in current times. In the 1960s and 1970s, when the global space programmes were in their early stages, people and governments accepted failures far more often. Second, although the physics remains the same, the technology for soft-landing has improved dramatically. With improvements in technology, possibilities for manoeuvre have also increased for space missions.
When the Soviets landed on the moon in the 1960s, it was a simple drop of a pressurized capsule that bounced on inf lated airbags. Current missions have to land far more precisely. During ISRO’s landing, for example, the lander will survey moon’s topography as it descends and adjust its path to land on the most optimal spot. Since the technology for such adjustment is available, ISRO does not want to make the lander unusable because it landed on a stone.
The entire descent is automated, and once the process starts ISRO engineers can only sit and watch. Manual control has its dangers. Two months ago, the Israeli firm SpaceIL’s Beresheet spacecraft crashed as it tried to land softly. It was supposed to compete for the Google X Prize, but had missed the deadline like all other participants, including India’s TeamIndus. Beresheet’s descent was not automated, and the delays in communication as it descended is supposed to be the reason for the crash.
The technology for interplanetary missions had been developed in stages over several decades in several laboratories of ISRO. The main spacecraft, including the structure and software, is developed in the U R Rao (URSC) satellite centre in Bangalore. The cameras and sensors are developed at the Laboratory for Electro-optical Systems (LEOS), also in Bangalore. The instruments are developed at the Physical Research Laboratory (PRL) and the Space Applications Centre in Ahmedabad.
The Vikram Sarabhai Space Centre (VSSC) develops the propulsion systems, and also the rocket that will launch the spacecraft. For the moon mission, the communication will be handled with assistance from NASA’s deep space network. Chandrayaan 2 will carry a small payload from NASA: a laser prospector array that will help measure distances accurately.
After the spacecraft lands, the rover will go out and survey the surface till it reaches a distance of 500 metres. The lander and the rover will investigate the physical and thermal properties of the lunar surface and the atmospheric plasma around the moon. The rover will examine the mineral composition of the lunar soil.
Finding the mineral composition of the moon is one of the most important aims of the mission. Helium-3 is supposed to be abundant on the moon, and this substance could be the basis of energy in the future. Which is why the mission is as strategic as it is scientific.