by Gurbir Singh
A satellite launched by the USSR would entail zero launch cost, and the mass of a satellite that a USSR launcher could deliver to orbit would be much more substantial than the 30-kg planned for India’s first launch vehicle, the SLV-3, which was then still under development. By August 1971, Rao secured a deal ‘in principle': India would build a satellite, and the USSR would launch it. Suddenly, in December 1971, Sarabhai died. Rao had had a long relationship with Sarabhai having completed his PhD under his supervision in the late 1950s. This loss seemed to ignite a deeper commitment within Rao to fulfil the task.[641] ISRO appeared to re-energise following Sarabhai’s demise, just as President Kennedy’s death intensified NASA’s resolve to land a man on the Moon. Perhaps, Rao’s professional duty to fulfil Sarabhai’s vision became his personal sacred mission.[642]
Further meetings in New Delhi and Moscow eventually led to an agreement that was signed on 10 May 1972 by academician Mstislav Keldysh (1911–1978), President of Russian Academy of Sciences, and Prof. M.G.K. Menon the interim ISRO chairman following Sarabhai's death.[643] India would build a satellite that the USSR would launch for free by the end of 1974. With a price tag of Rs.3 crore ($3.95 million), which included one crore in foreign exchange ($1.3 million), the project got the go-ahead from the Prime Minister in mid-1972. The project had a tight deadline to design, build, test and have India's first satellite ready for launch by the end of 1974.
This was a huge undertaking. India had no experience in building a satellite. It had no qualified personnel. It had no national technology industries with experience in building space-qualified components or subsystems, and it had no infrastructure to operate a satellite. Professor Menon was not convinced that India should proceed despite the offer of a free launch. Rao, however, was optimistic. He told Menon “If we want to go into space, this is the first real opportunity we have. As we are getting a free launch, we can start with a minimum amount of money and then build upon it. You just can't go straight to operational communication satellites or remote-sensing satellites till you have successfully built at least a couple of experimental satellites and established your capability to build complex satellites.”[644]
Rao was probably ISRO's most experienced and perhaps the only scientist in India capable of building space-qualified instruments. He had returned to India in 1966 from the US, having worked at MIT as a post-doctoral student and as an Assistant Professor at the University of Dallas in Texas. As a cosmic-ray scientist and joint principal investigator, Rao had been intimately involved in designing and building experiments and instruments for experiments that were launched on several NASA spacecraft, including Pioneer 6, 7, 8 and 9 and Explorer 34 and 41, during the 1960s. Collectively, they explored the solar system and ‘space weather’ by detecting and measuring interplanetary magnetic fields, energetic particles and plasma.[645]
The Prime Minister had provided the go-ahead to design and build India’s first satellite, and a launch date had been set by the USSR. The clock was ticking. Despite the reluctance from Thumba, a decision was taken to locate the satellite project in Bangalore (now Bengaluru) rather than Thumba. This was primarily to facilitate the short timescale to which ISRO was now committed. Bharat Electronics Limited (BEL) and other technology companies that would help deliver the electronics and the technical systems for the satellite project were located in Bangalore.[646] By September 1972, a site consisting of four sheds of 5,000 sq. ft. was acquired in the Peenya Industrial Estate in Bangalore. It was fitted out with a clean room, thermal vacuum chamber, laboratories and a workshop. It was initially staffed with about 40 mostly young engineers, none of whom had any experience in building satellites. This beginning in 1972 has evolved into today's ISAC with over 2,000 engineers and state-of-the-art facilities.
The frantic activity with which the project began continued with a remarkable degree of enthusiasm and round-the-clock activities through to the last few months prior to the launch. Some engineers even delayed their weddings (the average age of the engineers was 25), and none of them had seen a satellite before they embarked on building one. To minimise delays from red tape, Rao initiated a new procurement mechanism to purchase components that would bypass the traditional bureaucratic route.[647] With authority to place orders on the spot, Rao and his team visited the UK, US and France for specialised equipment and components that were not available in India. In addition, Rao used his contacts in the US to loan, on a replacement basis, components otherwise difficult to acquire to help build the initial engineering models.
Figure 12‑1 Aryabhata Prior to Assembly. Credit ISRO
The satellite design was to be relatively simple. It would be a spin-stabilised, 26-sided quasi-sphere with solar panels on 24 sides generating 46 watts of power to run the three onboard scientific experiments to detect and measure neutrons from the Sun, cosmic X-rays and gamma-rays. An essential requirement for a spin-stabilised satellite is that it is balanced around the spin axis. A specialised dynamic balance is used to detect uneven mass distribution around the axis of spin. A dynamic balance had been ordered from Germany, but it was delayed. With the launch date approaching, Rao's team designed and built a dynamic balance in just three months.
Sriharikota was to be the primary ground station for all communication with Aryabhata when in orbit, but there was no back-up communication channel. Two months before the launch date, two lavatories behind one of the four sheds at the newly acquired site in Bangalore were converted into an operational ground station complete with a fully steerable yagi array antenna.[648] Despite the challenging start, India’s first satellite was completed on time. Initially called the Indian Scientific Satellite Programme, three names for the satellite, Mitra, Jawahar and Aryabhata, were shortlisted in the final board meeting before launch. Aryabhata was a fourth-century mathematician-astronomer, Mitra meant friendship reflecting the India-USSR collaboration, and Jawahar meant the spirit of independence. A month before the launch, the name Aryabhata was selected by Prime Minister Indira Gandhi.[649]
Figure 12‑2 Professor U.R. Rao. August 2013. Credit Author
With its science package of three instruments, Aryabhata had a mass of 360 kg. It was placed in an orbit of 563 × 619 km by the Soviet Launcher Cosmos 3M from Kapustin Yar Cosmodrome on 19 April 1975.[650] Immediately after the launch, Aryabhata's telemetry was received at the USSR-based Bears Lake communication centre. Thirty minutes later, the first signals were detected at Sriharikota in India. The electricity supply connection to the third, ionosphere experiment, failed. Two of Aryabhata's three instruments, the X-ray astronomy and the solar neutron and gamma-ray experiments, returned data. Aryabhata captured X-ray data from Cygnus-X1, a well-known galactic X-ray source, it demonstrated satellite-tracking technique using tone-ranging and conducted an experiment to carry voice communication and electrocardiogram (ECG) data between Sriharikota and Bangalore. It also collected weather data (temperature, wind speed, pressure, etc.) from weather stations from remote weather stations around India.[651] This experiment was conducted in collaboration with the meteorological department of India. After orbit 41, a fault occurred in the power supply.[652] Some experiments had to be switched off, but the rest of the spacecraft continued to function normally. This action led some journalists to incorrectly report that the mission had failed and ended.[653]
Aryabhata, however, operated successfully beyond the targeted six months.[654] It demonstrated that Indian scientists and engineers were capable of designing, building and operating a satellite in space. Through the success of Aryabhata, ISRO acquired a level of confidence that can only be attained from the achievement of a goal that many believed to have been impossible. The NASA administrator visiting India in 1972 expressed his astonishment with the progress made in one year, later saying “I never thought you could do this.”[655] Even the USSR that had initiated the project “doubted that India could build a satellite in 2 1/2 years.”[656]
ISRO entered the Space Age at a time when, in India, there were “more bul
lock carts than cars” on the roads.[657] From empty sheds on an industrial estate, Rao and his team of novice engineers had done it in 31 months. Aryabhata’s lasting legacy was the new-found confidence that Indians in India could design, build and operate a functioning satellite in Earth orbit.
Earth Observation: Bhaskara and IRS
Earth Observation (EO) refers to any activity of acquiring information about the Earth’s surface, sea and atmosphere, including temperature, density, chemical composition, humidity, wind speed and direction. The technology used to acquire this information is collectively referred to as remote sensing.[658] These two terms, Earth Observation and remote sensing, are frequently used interchangeably. Although EO can be done using aircraft or balloons, modern techniques predominantly involve satellites in approximately 800 km polar orbit.[659] Satellites in GEO orbit can also undertake EO but are less common. India’s EO programme began very early in its space programme with the launch of its second satellite, Bhaskara-1, on 7 June 1979.
Arthur C. Clarke’s reference to the “new Star of India” referring to the communication satellite used in the SITE programme probably better represents ISRO’s EO, rather than communication, series of satellites since they have had a greater impact, albeit not as obvious, on the lives of ordinary Indians.[660] India has an immense and challenging geography with diverse and vast natural resources that include glaciers in the Himalayas, deserts in Rajasthan and tropical forests in Kerala, which can only be monitored efficiently by modern space-based technology. Space assets are critical to meet the challenges of climate change, increasing food production for a growing population and building infrastructure (such as electricity supply and road and rail transport links) for national economic growth.
India's domestic constellation of EO satellites guides Indian farmers on when the use fertilisers, where to dig wells, helps fishermen with information on when and where to go fishing, assists mining companies in locating minerals and metal and provides early warning to citizens who live in flood-prone areas. It helps the local and national governments to prepare for typhoons and the monsoon season and allows authorities to quantify the impact of the devastation caused by natural disasters to aid rescue and target resources in their aftermath.
A terrestrial remote sensing experiment in early 1970 proved that India could benefit from developing satellite-based EO function that several nations were already exploiting, paving the way for ISRO’s EO satellite programme.[661] Over a 5-day period in 1970, photographs were taken of coconut plantations in Kerala using two 70-mm Hasselblad cameras from a helicopter flying at 300 m. Upon processing the images, it was clear that this technique could be used to detect early signs of coconut wilt disease and help reduce the $2 million loss suffered by the Travancore-Cochin region annually.[662] More than half a century on, India has one of the world's most sophisticated programmes for EO to help monitor and manage the varied resources in its huge sprawling land mass of 3.3 million sq. km and its extensive coastal zone.[663]
This first remote-sensing experiment in India drew on international support just as the first rocket launch to space from Thumba had done in 1963. The Hasselblad cameras used were made in Sweden, the helicopter was provided by the USSR, the Ektachrome film came from the UK, and the key scientific advisor was American. The project was conducted under the auspices of a UN resolution that encouraged those nations that had expertise in EO to share with those that did not.[664] Having lost the race to the Moon, the USSR focused building a station in space and on asserting its political dominance on Earth. By the time of this UN resolution (16 December 1969), the US had successfully completed President Kennedy’s goal of manned flights to the surface of the Moon twice.[665] Just as the US and USSR had vied to entice non-aligned nations during the early 1960s, they again offered support with EO as a vehicle to grow their respective geopolitical influence.[666]
Bhaskara 1 and 2
Two days after the launch of Aryabhata, ISRO signed an agreement with the USSR to launch the next.[667] Bhaskara-1 was built rapidly partly facilitated by using parts developed for Aryabhata. The Bhaskara-1 design mandated that the Aryabhata’s stand-by structural model be used as the basic mechanical platform.[668]
Figure 12‑3 Bhaskara-1 Undergoing Testing in 1979. Credit ISRO
It was built once more by Professor U.R. Rao’s team in Bangalore but with input from all the major ISRO Centres. It was also spin-stabilised and placed into a near-circular orbit at an altitude of 534 km. Initially called the Satellite for Earth Observation, it was formally named Bhaskara-1 after launch on 7 June 1979.[669] Two weeks after the launch of Bhaskara-1, SAMIR was switched on and collected data, but a fault with a high-voltage electrical connection prevented both cameras from working for over a year. When switched on, air trapped within the high-voltage supply caused arcing (corona), resulting in large-scale electromagnetic interference. The cameras were switched off to prevent other electrical subsystems being affected. As ISRO engineers had predicted, over time the trapped air escaped. Eleven months after launch, the cameras were activated, and the first images of India by an Indian satellite from orbit were captured and transmitted; the mission was considered a success.[670] The primary objective for Bhaskara-1 was EO of the Indian landmass and the surrounding ocean, but it also served to help ISRO develop its processes, internal organisation and supporting infrastructure for gathering, analysing and managing the nation’s natural resources. Bhaskara-1 was formally switched off in March 1981 and disintegrated during re-entry in 1989.[671]
Bhaskara-2 was similar to Bhaskara-1 in design, size, mass, instrumentation, launch and orbital characteristics. Learning from Bhaskara-1, the high-voltage supply to the camera onboard Bhaskara-2 was redesigned. The TV camera operated from the outset as expected as did the SAMIR instrument, which had three instead of two frequency channels.[672] Bhaskara-2 was launched on 20 November 1981 and collected data successfully until 1984 when it ceased to operate. It burnt up during re-entry on 30 November 1991. Between them, Bhaskara-1 and Bhaskara-2 captured more than 2,000 images covering the complete Indian subcontinent.[673] With the Bhaskara programme, ISRO demonstrated its capability in designing and operating EO satellites. It was now ready to embark on a full-fledged national EO programme.
IRS-1A
Indian Remote Sensing Satellite IRS-1A launched in 1988 was ISRO's first fully functional remote-sensing satellite with two high-resolution Linear Imaging Self Scanner (LISS) cameras, LISS-1 with a 2-m resolution and LISS-2 with a 36-m resolution. LISS cameras used digital CCDs (Charged Couple Devices) as image sensors. CCDs were first developed as image sensors in 1969. NASA developed CCDs for use in space by 1975. ISRO's first CCD was tested in a laboratory in 1980 and in space in 1988 on-board IRS-1A. When ISRO developed IRS-1A, the PSLV was not yet operational, so ISRO sought launch assistance from the USSR. As the first remote-sensing satellite, it was subject to numerous simulations, structural, engineering and flight modelling and extensive cycles of reviews and tests.
Once IRS-1A was built and the final tests completed, two ISRO engineers flew with the flight model to the Cosmodrome in the USSR aboard Aeroflot IL-76 cargo aircraft on 24 January 1988. On 17 March, it was launched into a 900-km SSPO with 99° inclination by the Vostok launcher of the USSR. Once in orbit, first the solar panels, then LISS-1 and LISS-2 were activated.
Name
Date of Launch
Description
Cartosat–1
5 May 2005
Also known as IRS-P5, it was the first Indian satellite to provide in-orbit stereoscopic images using two panchromatic cameras sensitive in the visible spectrum. Images from it were sold commercially. It exceeded its planned lifetime of 5 years.
Cartosat-2
10 Jan 2007
Has a high-resolution panchromatic camera offering 1 m resolution. It was launched at the same time as the SRE-1, Lap-lan Tubsat for Indonesia and Peuensat-1 for Argentina. It exceeded its planned lifetime of 5 years.
Cartos
at-2A
28 April 2008
Was launched on PSLV-C9, along with an Indian mini-satellite and eight nano-satellites from Japan, Canada, Germany, Denmark and the Netherlands.Cartosat-2A is equipped with an agile camera platform and able to image selected areas under its orbit more frequently.
RISAT-2
20 Apr 2009
India's first dedicated reconnaissance satellite with day and night all-weather monitoring capability. In the press, it has been referred to as a spy satellite, in part, because its launch was not televised live like usual. It was called RISAT-2 because it incorporates Radar Imaging technology. RISAT-2 was acquired at short notice from Israel. RISAT-1 was in development at the time but not ready for launch hence RISAT-2 preceded RISAT-1 to orbit.
Oceansat-2
23 Sep 2009
Was designed to provide continuity of service for users of the Ocean Colour Monitor (OCM) instrument on Oceansat-1 launched in 1999. Oceansat-2 has two other instruments in addition to the Ocean Colour Monitor (OCM-2).
Cartosat–2B
12 Jul 2010
Identical to Cartosat-2A with a panchromatic camera capable of imaging a strip of 9.6 km with a resolution of about 1 m.
Resourcesat-2
20 Apr 2011
A remote-sensing satellite intended to continue with the remote-sensing data services provided by Resourcesat-1 to global users.