MINI TICKET TO SPACE
Small satellites are providing cost-effective and reliable means of space exploration
Forget bulky spacecraft. Small satellites are a cheaper and reliable means to explore space
ON JUNE 30, Satish Dhawan Space Centre in Sriharikota launched a rocket. On board were five satellites.The main passenger was a French Earth observation satellite, weighing 700 kg.It was accompanied by four tiny ones: two from Canada and one each from Germany and Singapore.None of these weighed more than 15 kg.
This is a “global endorsement of India’s space capability”, declared Prime Minister Narendra Modi soon after the successful launch of the rocket, Polar Satellite Launch Vehicle (pslv)-c23. Once in space, the German satellite will monitor sea-traffic,the Canadain satellites will test formation flying of spacecraft and the one from Singapore will establish inter-satellite link.
Small satellites are cheaper and miniature versions of the behemoth that weigh in tonnes. These can be categorised as picosatellites (under 1 kg), nanosatellites (1 kg to 10 kg) or microsatellites (10 kg to 100 kg).
The world’s first small satellite was launched on October 4, 1957, by the Soviet Union. It was called Sputnik1 and weighed 84 kg. Riding high on the Cold War sentiment, the US’s first small satellite— Explorer 1—followed soon in January 1958. In the 55 years since then, the sector is revolutionised through sustained research and is no longer a government-exclusive domain. At least 170 small satellites now orbit the Earth and are engaged in various activities,from tracking wildlife,monitoring sites ravaged by natural disasters and looking for crashed planes like the recent MH370 to conducting space-based experiments, like searching for Earth-like planets outside the solar system. Their utility is limited only by the experimenter’s imagination.
In the past, the Indian Space Research Organisation (isro) has launched small satellites like ims1 and hamsat. ims1, also called Third World satellite, was an Earth observation satellite and is past its life. hamsat still caters to the amateur radio community.At present,most small satellites launched by isro are built either by students at Indian universities or by other countries.
While isro offers service to foreign agencies for a price, it offers free rides to the ones designed by students (see interview).
India’s first student satellite was anusat. Weighing 40 kg,the microsatellite was built by Anna University in Tamil Nadu and was launched in 2009. A year-and-a-half later, students from seven engineering colleges in Karnataka and Andhra Pradesh launched a picosatellite,studsat,which weighed 950 g. A proliferative year for Indian small satellites, 2011 saw the launch of three student satellites: 92 kg youthsat, developed under an India-Russia collaborative project; 10.9 kg srmsat developed by srm University, Chennai,and 3 kg Jugnu by iit Kanpur.
“Creating Jugnu was educative and interesting,” says Shashank Chintalgiri, the then student leader of the team. “As a technology demonstration mission, where the primary objective was to develop necessary technology and skills,the Jugnu team was able to show that development of a complete, robust, field-deployable technology was possible in the setting of an Indian university,” he adds.Among other objectives,Jugnu hoped to generate imaging data for agriculture. As per formal mission success parameters, Chintalgiri pegs Jugnu’s success rate at somewhere between 60 and 70 per cent.
While isro has not launched any student satellite after 2011, many are being developed across the country.
One such attempt is by students at Manipal University in Karnataka. Their small satellite, Parikshit, aims to generate a thermal map of the Indian subcontinent that will help identify urban heat islands. It will also demonstrate the satellite de-orbiting technology, developed by Australia’s Saber Astronautics. “Conventionally, a satellite remains in orbit,even after mission life.This adds to the amount of space debris. We are using a technology to pull the satellite down and burn it up as it re-enters the atmosphere,” says Chandra Shekhar,team member of the project and a BTech final year student in computer science. Before deploying the technology on Parikshit, student leader of the team, Adheesh Boratkar, travelled to nasa to test its efficacy in zero-gravity
SORIT / CSE