ISRO starts 22-hour countdown to PSLV rocket's 63rd launch

At 7:59 am IST on Saturday (17th May), the Indian space agency ISRO commenced the 22-hour countdown to the May 18th launch of the EOS-09 earth-imaging satellite aboard the PSLV rocket, WION has learnt. At 5:59 am Sunday, the PSLV-XL rocket is expected to blast-off from the first launchpad of the Satish Dhawan Space Centre, Sriharikota, India's lone spaceport. The exact launch time is likely to change by a few seconds or a few minutes, depending on the possibility of space debris or other satellites coming in the rocket's flight path.

PSLV-C61 marks the 63rd flight of India's most flown rocket, the Polar Satellite Launch Vehicle. This also marks the 101st launch from the spaceport that is situated on India's southeast coast. EOS-09 is a radar imaging satellite (earlier known as RISAT) that is capable of day and night imaging. It can see through clouds, deliver images under all weather conditions. This 1,700kg satellite is meant to have an operational life of at least five years. Almost 18 minutes after lift-off, the EOS-09 satellite will be placed in its Sun Synchronous Polar orbit that is 529 km above the Earth.

After the satellite is injected into its orbit, the final stage of the rocket would use orbit change thrusters to lower its orbit. This orbit lowering would gradually help in de-orbiting the spent upper stage of the rocket, thereby helping reduce space debris. Likewise, even the EOS-09 satellite is carrying extra fuel for de-orbiting. Closer to the satellite's end of life, the satellite will use the extra fuel to lower its orbit, which will ensure that it naturally de-orbits and burns up and does not end up as space debris.

The launch of this strategic satellite comes a week after nuclear-armed neighbours India and Pakistan announced a ceasefire, following three days of a rapidly escalating warlike situation. However, it must be emphasised that the space launch mission taking place at this time is a mere coincidence. The PSLV rocket takes a little over a month to assemble, and it takes well over a year to build a satellite like EOS-09. At the Indian spaceport, the preparations for this launch are said to have commenced in mid-March, more than a month before the situation between India and Pakistan deteriorated.

India operates multiple satellites for strategic purposes. This includes the Cartosat series of satellites, the RISAT (Radar imaging satellites) series, EMISAT, etc. In addition to this, there are large communication satellites such as GSAT-7 that cater to the Indian Navy and the GSAT-7A that cater to the Indian Air Force and Strategic Forces Command.

RISAT series of satellites are unique because they do not take pictures like a conventional camera-carrying satellite. Instead of giving an optics-based picture (like a photograph), the RISAT beams radar waves onto the Earth. The features on the earth's surface, (buildings, trees, mountains, water bodies, roads) reflect these radar waves back to the satellite. It is by collecting and processing the reflected radar waves that RISAT provides the end product, which is round-the-clock, all-weather imagery. While conventional optical satellite images are in colour, radar satellite images are inherently black and white.

In recent years, ISRO has been following a different naming convention where all earth-imaging satellites are referred to as 'EOS', which stands for Earth Observation Satellite. It must also be emphasised that all satellites equipped with a camera can be put to defence and civilian use. In total, India has about 55 satellites in orbit that serve various purposes.

Following the April 22nd Pahalgam terror attacks in Jammu and Kashmir, ISRO Chief Dr V. Narayanan had cited the need for launching 100-150 satellites to keep a constant vigil over India's 7,500 km long coastline and 15,000 km long land borders. However, it must be remembered that ISRO cannot build and launch any of these satellites without the necessary approvals and budget allocations from the relevant ministries of the Indian Government.

As per the existing government procedure, the specific ministry or department that will be using the satellite will have to obtain approvals and allocate funds for it before placing orders with ISRO for building and launching the rockets and satellites. For example, surveillance satellites would have to be approved and funded by the Defence Ministry, while weather satellites would have to be approved and funded by the Ministry of Earth Sciences.

40 Indian Parliamentarians to visit Sriharikota, witness PSLV-C61 launch

WION has learnt that 40 Indian parliamentarians, who are part of the Parliamentary Standing Committee of Science and Technology, will be at the spaceport in Sriharikota to witness the launch. The parliamentarians are to visit multiple government establishments across two southern Indian states, Tamil Nadu and Andhra Pradesh, between 16th and 19th May.