It was in May last year when the chairman of Indian Space Research Organisation (ISRO), K Sivan, had unveiled that the Indian space agency is planning to develop world-class propulsion technology to ensure cost-effectively re-usable, recoverable, re-startable and reliable space launches.
Now in a latest, ISRO chairman has again unwrapped more on the ambitious plan of ISRO where it is now looking to perfect its reusable launch vehicle (RLV) technology not in first-stage recovery, which Elon Musk promoted SpaceX has already achieved, but also to developing technology which would allow to recover second stages of a rocket, reports Times Of India.
The private space agency, SpaceX, has a long term goal to reuse both first & second stages of their orbital launch vehicle and the company has achieved a successful landing and recovery of the first stage in December 2015. However, recovering the second stage is much more difficult to recover and no space agency including SpaceX has achieved this. It is due to the heat shield, landing engines and other equipment required to achieve it.
To accomplish this difficult task, ISRO is going to conduct an advanced version of the reusable launch technology (RLV) test in June-July.
According to ISRO chairman, the space agency is working on a reusable launch technology in order to recover the first and second stages of a rocket to reuse them in order to cut cost and carry heavier payloads. The first rocket stage will be recovered on a vertical landing spot on the sea like SpaceX has been doing it with its Falcon family of rockets.
The RLV- Technology Demo was successfully completed its first test flight on 23 May 2016, which lasted for 770 seconds and reached a maximum altitude of 65 kilometers (40 mi). It was designed to evaluate various technologies, and the development of the final version is expected to take 10 to 15 years. The fully developed RLV is expected to take off vertically like a rocket, deploy a satellite in orbit, return to Earth, and land on a runway.
For the second stage, ISRO is developing a winged body like a space shuttle. This shuttle will be attached as the second stage in a rocket. It will carry the top portion of the rocket comprising a satellite or spacecraft to space. Once it injects the satellite in its orbit, the shuttle will glide back to the earth and land on an airstrip like an aircraft.
Reusable Launch Vehicle – Technology Demonstrator (RLV-TD) is one of the most technologically challenging endeavors of ISRO towards developing essential technologies for a fully reusable launch vehicle to enable low-cost access to space. The configuration of RLV-TD is similar to that of an aircraft and combines the complexity of both launch vehicles and aircraft. The winged RLV-TD has been configured to act as a flying test bed to evaluate various technologies, namely, hypersonic flight, autonomous landing, and powered cruise flight. In the future, this vehicle will be scaled up to become the first stage of India’s reusable two-stage orbital launch vehicle.
RLV-TD consists of a fuselage (body), a nose cap, double delta wings, and twin vertical tails. It also features symmetrically placed active control surfaces called Elevons and Rudder. This technology demonstrator was boosted to Mach no: 5 by a conventional solid booster (HS9) designed for low burn rate. The selection of materials like special alloys, composites and insulation materials for developing an RLV-TD and the crafting of its parts is very complex and demands highly skilled manpower. Much high technology machinery and test equipment were utilized for building this vehicle.
A team of 750 engineers at Vikram Sarabhai Space Centre, National Aeronautical Laboratory, IITs and Indian Institute of Science worked on the design and development of RLV-TD and the associated rocket. RLV-TD underwent 120 hours of the wind tunnel, 5,000 hours of computational fluid dynamics and 1,100 runs of flight simulation tests. RLV-TD has a mass of 1.75 tonnes, wingspan of 3.6 meters and an overall length of 6.5 meters (excluding the rocket).
As mentioned above, ISRO previously tested its RLV in 2016. Back then, the HS9 solid rocket booster carrying RLV-Technology Demonstrator (RLV-TD) lifted off from the First Launch Pad at Satish Dhawan Space Centre, Sriharikota. After 91.1 seconds, the HS9 burn out took place, after which both, HS9 and RLV-TD, reached to a height of about 56 km and then the RLV-TD separated from HS9 booster and again went up to a height of around 65km. The RLV-TD then descended back into the atmosphere, surviving re-entry, and glided down a defined landing spot over the Bay of Bengal. The next test will be conducted on June-July and it will be different as a helicopter is supposed to take the RLV to a ‘considerable height’ and drop it. The shuttle is said to then glide back to Earth and land on an airstrip. The landing strip could be set in the Andaman and Nicobar islands but this is currently speculation.