Taking steps towards developing a reusable launch vehicle capable of sending spacecraft into orbit and returning to the earth’s surface, Bharat successfully launched its first ‘Swadeshi’ space shuttle, RLV-TD
Radhakrishna Rao
In a significant step forward towards realising a fully operational, home grown, reusable space vehicle that will substantially decrease the cost of space missions, Indian Space Research Organisation (ISRO) on May 23 successfully accomplished the landmark, maiden flight of the Technology Demonstrator (TD) version of the Reusable Launch Vehicle (RLV) from Satish Dhawan Space Centre, Sriharikota (SDSC).
Sources in ISRO confirmed that the RLV-TD mission was carried out successfully as planned. It took around ten minutes for the winged experimental flight vehicle to splash down into the Bay of Bengal after its smooth take off with a booster stage. This is the first of the series of experiments meant to build a robust technological base for realising a Two Stage To Orbit (TSTO), fully reusable, space vehicle that would replace the current genre once only used expendable, chemical fuel driven rockets. The most striking advantage of a reusable space vehicle is that would facilitate routine orbital journeys with a little turnaround time. All said and done, ISRO considers this mission as a preliminary step towards demonstrating the feasibility of a range of technologies involved in the realisation of a reusable space vehicle. Even so, the success of RLV-TD mission is a major boost to ISRO’s ambition of building an operationally viable, economically affordable and safe to operate reusable space vehicle.
As planned, at the end of the mission, the winged vehicle re-entered the atmosphere at hypersonic speed of more than Mach 5 to splash down into what ISRO described as the “virtual runway” of the Bay of Bengal. In this instance, the vehicle will not be recovered from the sea. Described as India’s own space shuttle, the RLV envisaged by ISRO is considered a sure shot solution to achieve low cost, reliable and on demand access to space. The strategic significance of such a vehicle lies in the fact that it could be deployed to replace satellites on a short notice at a highly affordable cost. Indeed for the Indian defence forces that would be looking forward to replace or replenish their spacecraft constellations at short notice, RLV cannot but be an ideal option. Moments after this successful mission, Prime Minister Narendra Modi roundly lauded the efforts of Indian space scientists for the successful launch of RLV-TD mission. “Launch of India’s first indigenous space shuttle RLV-TD is the result of the industrious efforts of our scientists,” said Modi. He was also quick to highlight the dynamism and dedication with which ISRO scientists worked over the years in an exceptional and inspiring manner.
As envisaged now, the objective of the just concluded RLV-TD test flight was to evaluate the “gliding dynamics” of the winged vehicle while splashing down into the Bay of Bengal. The future technology demonstrator missions of RLV will end up on the specially created runway in SDSC. According to ISRO, a fully operational reusable space vehicle could help reduce the launch cost by as much as ten times. The end goal is to realise a highly affordable launch cost of US$2000 per kg of payload. For ISRO, it took about five years to prepare the ground for the maiden flight of RLV-TD. Clearly and apparently, the RLV-TD flight test also helped evaluate the capability of the vehicle to survive a supersonic re-entry speed. During the descent phase, small thrusters were used to navigate the vehicle into its designated splash down point. All said and done, it would take more than a decade for ISRO to put in place a fully functional reusable space vehicle.
As planned, the winged space vehicle was taken to a height of 56-km by a 9-tonne heavy solid fuel driven booster rocket named HS-9 which was attached to it. From this point, it climbed to attain a height of 65-km. Thereafter, the vehicle entered the earth’s atmosphere in a planned sequence to splash down into the Bay of Bengal. The successful test of this 6.5-m long aeroplane like structure with a take off weight of 1.75 tonne marks the bold attempt by ISRO to reinforce India’s position as a front ranking space power. Interestingly, this experimental space vehicle has been configured to serve as a flying test bed to evaluate a range of technologies including hypersonic flight, autonomous landing, powered cruise flight and flight using air breathing propulsion towards realising a two stage to orbit (TSTO) fully reusable space vehicle. Moreover, some of the technologies being developed for India’s reusable space vehicle would give a big thrust to the Indian manned flight programme which is yet to be approved by the Indian Government.
According to Dr K Sivan, Director of the Thiruvananthapuram based Vikram Sarabhai Space Centre (VSSC), the largest Indian space establishment that focusses on the launch vehicle technology development, preparing RLV-TD for its maiden flight was a really complex and challenging task. For, as pointed out by Sivan, the vehicle was required to go through very time consuming tests wherein most intricate and detailed data have to be obtained. In a way, RLV-TD exemplifies the fusion of aircraft and rocket technologies. In distinct contrast to a conventional expendable rocket which spends a very little of its flighttime in the atmosphere, the RLV system spends all the time in the atmosphere. There is no denying the point that this sleek winged vehicle exemplifies the philosophy of frugal engineering perfected by ISRO over the years. As it is, the current RLV-TD vehicle is roughly six times smaller than the final version. Indian Government has invested Rs.950-million for RLV-TD described as the precursor of Swadeshi space shuttle.
As it is, the successful RLV-TD mission was the first of the four flight tests that ISRO has planned with a view to incrementally evaluate the behaviour of the vehicle under actual flight conditions as well as the performance of the advanced scramjet engine that will propel the vehicle.
All said and done, India’s well thought out plan for embarking on the development of a home grown reusable space vehicle assumes significance in the backdrop of the fact that not long back US had abandoned its space shuttle space transportation system touted as world’s first ever reusable space vehicle because it was found to be far from safe, prohibitively costly and technologically far from mature. It is now a part of the history that the space shuttle had killed more people than any other launch vehicle.And finally in July 2011 USA had to bid a good bye to Space shuttle which took off in 1981. Of course, currently two US private space enterprises are vigorously working towards developing reusable space vehicles for a variety of end uses including supporting “space tourism”. The US based rocket companies, Blue Origin and Space X, are busy carrying out tests for realising their own versions of the reusable space vehicle. While Space X is led by billionaire Elon Musk, Blue Origin is headed by Amazon chief Jeff Bezos. Elsewhere, Japan, Russia and European Space Agency (ESA) are struggling it out to give a shape to their own version of reusable space vehicle.
(The writer is a freelance columnist who writes on science, Tech and Defence related issues)
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