In many ways, the successful flight of India's first reusable space launch vehicle is a tribute to the vision of A.P.J. Abdul Kalam, the late former president of India and top rocket scientist. Way back in 1973, when Kalam took over as the project director of India's first satellite launch vehicle, SLV-3, he dreamt of doing what the Indian Space Research Organisation (ISRO) eventually accomplished on May 23, 2016. While developing SLV-3, Kalam would watch the restless sea at Thumba in Kerala, the headquarters of ISRO's rocketry. Kalam told me it was then that he visualised building a rocket launcher that could be reused after it ejected a satellite into orbit. He explained that instead of letting the launcher tumble uselessly into the ocean as junk, if it could be guided back and reused, the cost of launching a satellite could be cut to a tenth. He even worked out the dimensions and trajectory of such a launcher and circulated it to ISRO scientists.

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For ISRO, which was then taking baby steps into space, Kalam's plan was way ahead of its time. The organisation was just conceiving its first launch vehicle and was keen on proving its ability to put something into space-however small the object. So, naturally, the plan for a reusable launcher was kept on hold. Also, the US Space Shuttle programme, though conceived in the mid-1960s, was still on the drawing board and its first four orbital tests flight would happen only in 1981. Considered state-of-the-art in reusable technology, the Space Shuttle would fly a total of 135 missions before it was retired in 2011 by NASA because of spiralling costs and far safer means of launching satellites now available.

So, almost 40 years after Kalam conceived it, and five years after the US mothballed its Space Shuttles, why is the nation celebrating what could be considered ISRO's reinvention of the wheel? Conscious of such carping, A.S. Kiran Kumar, the affable ISRO chief, took pains to point out to me that since the Shuttle was designed, technologies have undergone dramatic changes. As he put it, "It's the first step in our primary aim to find ways and means of bringing down the cost of accessing space. If we don't do this, we will be beaten by a host of other countries and will have to shut shop."

Kumar is right. ISRO is not building reusable launch vehicles as a flight of fancy, but because these have now become a necessity to stay on top in the space business. The Big Five players that have commercial satellite launch vehicle capabilities-the US, Russia, Europe, China and India-offer only disposable rockets to their customers. That means if a satellite is launched, the rocket that sends it into a polar orbit of around 800 km around the Earth (for remote sensing), or one that tosses it to a 36,000 km orbit (for communications), either drops like a deadweight into the ocean or becomes space junk.

However, the budget constraints that followed the global economic downturn in 2008, saw user-nations build tremendous pressure to bring down the cost of launching satellites. Currently, to send a satellite weighing over a tonne, the cost per kg is between $15,000 and $20,000, depending on the orbit. That make the cost of ISRO launching a satellite range from Rs 150 crore to Rs 200 crore. If ISRO masters reusable technology to bring the launcher back after it ejects a satellite into space, it would cut launch costs by as much as 80 to 90 per cent-which will make it highly competitive in the hi-tech race for space.

The big quest is to make satellite launch vehicles as durable as commercial aircraft, and to keep them in continuous operation by refuelling and repairing them after a flight. Apart from the Big Five, almost every space-faring nation, including Japan, Australia and Brazil, is dusting up its plans for reusable rockets. Perhaps the most exciting development in recent times has been the entry of new private players such as Elon Musk's Space X and Richard Branson's Virgin Galactic. The two billionaire businessmen now regard space as the next frontier to conquer. In the past year, Space X has dazzled the world by successfully bringing back a booster rocket from sub-orbit and landing it on a floating pad on the ocean as well as on land.

Graphic by Raj Verma Graphic by Raj Verma

India's first shot at reusable rocket launchers was far more modest. The plan was to launch a scaled-down model of an unmanned shuttle from its Sriharikota launch station (SHAR) and then use onboard radars to guide it gently over the waters of the Bay of Bengal. The shuttle was one-fifth of its original size, mounted on a conventional solid rocket that was launched into sub-orbit of around 65 km at a speed of Mach 5. K. Sivan, the director of the Vikram Sarabhai Space Centre in Thumba, who led a team to build and launch India's first reusable launch vehicle, says the first flight test has given them "the confidence to go ahead with our plans to build the next generation of launch vehicles".

To do that, Sivan points out that not only will they have to master several key technologies but get sufficient funds sanctioned by the Central government for the project. In the next demonstrator test, scientists are planning to put an undercarriage and mount a rocket engine onto the shuttle so that, after ejecting its payload, it could turn back, cruise for a while, and then land on the runway at SHAR. The team needs to develop a new semi-cryogenic engine (fuelled by kerosene and liquid oxygen) to not only give it the necessary boost, but also to enable them to manoeuvre the craft for landing. They also have to develop far lighter materials for the structure to withstand the searing heat of re-entry and maintain integrity.

If all these technologies are mastered, which Sivan estimates will take anything from 10 to 15 years, ISRO would be at the cutting edge of not just space technology but aeronautics. The latest test was the first time that India built and launched a winged craft to reach a speed of Mach 5 and then guided it back for a landing. ISRO has, over the years, involved private companies in the development of its launch vehicles and satellites, thereby cutting down government investments in production. PSLV, its workhorse launcher, is now a commercial success. And after initial hiccups, GSLV, its heaviest launch vehicle, is getting there.

To the credit of ISRO, it has always demonstrated a propensity to think big and reach for the stars. Its string of recent successes, including missions to Mars and the Moon, as well as establishing an Indian GPS system, are laudable. Now Prime Minister Narendra Modi, who has been supportive of ISRO, should back its latest venture to develop the next generation of launch vehicles and become world leaders in it. As Kalam once said: "You must dream, because dreams generate thoughts and thoughts are converted to action." Let ISRO continue to dream big.

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