So what's ISRO testing on May 23?

Apologies about the frequency of updates having fallen off. Work’s been hectic at The Wire – we’re expanding editorially, technologically and aesthetically – but more to the point, Delhi’s heat ensures my body has no surplus energy when I get back from work to blog (it’s a heartless 38 ºC at 10 pm). Even now, what follows is a Facebook Note I posted on The Wire‘s page yesterday (but which didn’t find much traction because of the buildup to today’s big news: the election results from five states).

At about 9.30 am on Monday, May 23, a two-stage rocket will take off from the Sriharikota High Altitude Range and climb to an altitude of 48 km while reaching a speed of ~1,770 m/s. At that point, the first stage – a solid-fuel booster – will break off from the rocket and fall down into the Bay of Bengal. At the same time, the second stage will still be on the ascent, climbing to 70 km and attaining a speed of ~1,871.5 m/s. Once there, it will begin its plummet down and so kick off the real mission.

Its designation is RLV-TD HEX1 – for Reusable Launch Vehicle Technology Demonstration, Hypersonic Experiment 1. The mission’s been in the works for about five years now, with an investment of Rs.95 crore, and is part of the Indian Space Research Organisation’s plans to develop a reusable launch vehicle in another 15 years. The HEX1 mission design suggests the vehicle won’t look anything like SpaceX’s reusable rockets (to be precise, reusable boosters). Instead, it will look more like NASA’s Space Shuttle (retired in 2011): with an airplane-like fuselage flanked by delta wings.

And the one that’ll be flying on Monday will be a version six-times smaller in scale than what may ultimately be built (though still 6.5-m long and weighing 1.7 tonnes). This is because ISRO intends to test two components of the flight for which the RLV’s size can be smaller. The first (in no specific order) will be the ability of its body to withstand high temperatures while falling through Earth’s atmosphere. ISRO will be monitoring the behaviour of heat-resistance silica tiles affixed to the RLV’s underside and its nose cone, made of a special carbon composite, as they experience temperatures of more than 1,600º C.

The second will be the RLV’s onboard computer’s ability to manoeuvre the vehicle to a designated spot in the Bay of Bengal before crashing into the water. That spot, in a future test designated LEX and a date for which hasn’t been announced, will hold a floating runway over 5 km long – and where the RLV will land like an airplane. A third test will check for the RLV’s ability to perform a ‘return flight experiment’ (REX) and the final one will check the scramjet propulsion system, currently under development.

ISRO has said that the RLV, should it someday be deployed, will be able to bring down launch costs from $5,000 per kg to $2,000 per kg – the sort of cuts SpaceX CEO Elon Musk has repeatedly asserted are necessary to hasten the advent of interplanetary human spaceflight. However, the development of advanced technologies isn’t the only driver at the heart of this ambition. Private spaceflight companies in the US recently lobbied for a ban against the launch of American satellites onboard ISRO rockets “because it would be tough for them to compete against ISRO’s low-cost options, which they also alleged were subsidised by the Indian government”.

Then again, an ISRO official has since clarified that the organisation isn’t competing against SpaceX either. Speaking to Sputnik News, K. Sivan, director of the Vikram Sarabhai Space Centre in Thiruvananthapuram, said on May 17, “We are not involved in any race with anybody. We have our own problems to tackle. ISRO has its own domestic requirements which we need to satisfy.”

So, good luck for HEX1, ISRO!

Featured image: The PSLV C33 mission takes off to launch the IRNSS 1G satellite. Credit: ISRO.

Note: This post earlier stated that the HEX1 chassis would experience temperatures of 5,000º C during atmospheric reentry. It’s actually 1,600º C and the mistake has been corrected.