ISRO’s recent achievements are remarkable but it must tame ‘naughty boy’ GSLV
By Asit Manohar
With the successful launch of “eye in the sky” Cartosat-2E satellite with surveillance capabilities last Friday, the total number of satellites being used for military purpose has gone up to 13, an ISRO source said. These satellites, which can be used for surveillance and mapping border areas, are primarily used for keeping an eye on enemies both on land and sea+ .
“Most of these remote-sensing satellites are placed in the near-earth orbit. Placing these satellites at the sun-synchronous polar orbit (about 200-1,200 km above the Earth’s surface) helps in better scanning of the earth. However, some of these satellites have also been put in the geo orbit,” the source said. The recently launched 712-kg Cartosat-2 series spacecraft is an advanced remote sensing satellite+ capable of providing scene-specific spot imagery.
The Cartosat-2 can accurately spot objects within a square of 0.6 metre by 0.6 metres.
“The 13 satellites used by the military for surveillance include Cartosat 1 and 2 series and Risat-1 and Risat-2,” the ISRO source said.
The Navy also uses Gsat-7 for real-time communication among its warships, submarines, aircraft and land systems. India also has the capability to launch anti-satellite weapon (ASAT), which is meant to destroy enemy satellites.
Only the US, Russia, and China are known to have developed these weapons.
Earlier in February 2017, ISRO boosted its reputation further when it successfully launched a record 104 satellites in one mission from Sriharikota by relying on its workhorse Polar Satellite Launch Vehicle rocket. An earth observation Cartosat-2 series satellite and two other nano satellites were the only Indian satellites launched: the remaining was from the United States, Israel, the UAE, the Netherlands, Kazakhstan and Switzerland. Of the 101 foreign satellites launched, 96 were from the U.S. and one each from the other five countries. Till now Russia held the record of launching 37 satellites in a single mission, in 2014, while the National Aeronautics and Space Administration of the U.S. launched 29 satellites in one go in 2013. Last June, ISRO had come close to NASA’s record by launching 20 satellites in one mission. But ISRO views the launch not as a mission to set a world record but as an opportunity to make full use of the capacity of the launch vehicle. The launch is particularly significant as ISRO now cements its position as a key player in the lucrative commercial space launch market by providing a cheaper yet highly reliable alternative. At an orbital altitude of around 500 km, the vehicle takes about 90 minutes to complete one orbit. Though ISRO had sufficient time to put the satellites into orbit, it accomplished the task in about 12 minutes. With the focus on ensuring that no two satellites collided with each other, the satellites were injected in pairs in opposite directions. Successive pairs of satellites were launched once the vehicle rotated by a few degrees, thereby changing the separation angle and time of separation to prevent any collision.
ISRO plans to launch more Cartosat-2 series satellites and even an improved version. Besides setting the record for the most number of satellites launched in a single mission, the Indian space agency has launched two nano satellites weighing less than 10 kg. It is a technology demonstrator for a new class of satellites called ISRO nano satellites (INS). The main objective of the INS, which will be launched together with bigger satellites, is to provide a platform on which payloads up to 5 kg from universities and R&D laboratories, and ISRO itself can be easily integrated for carrying out scientific research activities. With many Indian universities already building and launching nano satellites, the availability of a dedicated nano satellites platform is sure to boost space research in India.
India has long proven its proficiency in the kind of rocket that launched a record number of satellites at one go on Wednesday, but the country’s future growth in space will depend exclusively on its success with the indigenous Geosynchronous Satellite Launch Vehicle (GSLV) program that is now far from perfect.
The Polar Satellite Launch Vehicle (PSLV), which was used to deliver 104 satellites into Earth’s orbit, has been the work horse of Indian space programme, notching up about 40 successful launches since 1994. But it cannot carry communication satellites weighing more than 2,000kg into space.
This limits India’s ability to compete with countries such as France or China for the $300 billion global space industry, and also forces it to hire foreign space firms to launch its own heavy satellites.
So far, India’s GSLV programme is far from reliable, having been successfully launched only twice using a home-built cryogenic engine after more than a decade of setbacks. The repeated failure of the programme saw GSLV being termed as the ‘naughty boy’ of ISRO.
The first time it did so was in January 2014, launching the GSLV-D5 which put ISRO on the map of a select club of nations that can launch heavy satellites. The agency again successfully launched a GSLV-MkII rocket in September last.
But experts see these as just the first step in the direction of developing a reliable launch system for the delivery of heavy satellites into different orbits.
“Our aim should be to become proficient in GSLV launches because then we can carry payload category of 4500-5000 kg,” said S Satish, formerly of ISRO.
“The big bucks of space business lies in that.”
For Indian space scientists, that goal is now being worked upon. ISRO is developing the GSLV-Mk III launch vehicle which is expected to deliver payload weighing 4500 to 5000kg.
In comparison, Russian and French rockets can carry four times that payload and into higher orbits.
“Now we are targeting GSLV MkII and then Mk III… a series of launch activities (have been) planned to ensure that like last year this year also we have many exciting events coming,” ISRO chief AS Kiran Kumar said in February after the successful launch of Cartosat 2.
ISRO’s long term plans include undertaking more than 50 missions and deploying 500 satellite communications transponders by 2019.
That is easier said than done, given that ISRO is still to consistently prove the GSLV design, realisation and sustained firing of its indigenous cryogenic engine.
Until then, experts say, it cannot hope to offer itself as a low-cost option for launching heavy satellites that would give stiff competition to global commercial satellite launch companies such as Europe’s Ariane or Russia’s Proton rockets.