AVATAR

AVATAR (Sanskrit: अवतार) (from "Aerobic Vehicle for Hypersonic Aerospace TrAnspoRtation") was a concept development effort for a single-stagereusable spaceplane capable of horizontal takeoff and landing, by India's Defense Research and Development Organization along with Indian Space Research Organization and other research institutions. The mission concept was for cheaper military and civilian satellite spacelaunches.

The notional specification was for a payload weighing up to 1,000 kg to low earth orbit. It would be the cheapest way to deliver material to space at about US$67/kg. Each craft was anticipated to withstand 100 launches.

The idea was to develop a hyperplane vehicle that can take off from conventional airfields, collect air in the atmosphere on the way up, liquefy it, separate oxygen and store it on board for subsequent flight beyond the atmosphere. The AVATAR RLV was first announced in May 1998 at theAero India 98 exhibition held at Bangalore. It is planned to be the size of a MiG-25 fighter and would be capable of delivering a 500 kg to 1,000 kgpayload to low earth orbit at very low cost for an estimated vehicle life of 100 launches.

AVATAR is proposed to weigh only 25 tonnes in which 60 per cent of mass will be liquid hydrogen fuel. The oxygen required by the vehicle for combustion is collected from the atmosphere, thus reducing the need to carry oxygen during launch. AVATAR is said to be capable of entering into a 100-km orbit in a single stage and launching satellites weighing up to one tonne.

AVATAR RLV-TSTO

AVATAR would take off horizontally like a conventional airplane from a conventional airstrip using turbo-ramjet engines that burn air and hydrogen. Once at a cruising altitude, the vehicle would use scramjet propulsion to accelerate from Mach 4 to Mach 8. During this cruising phase, an on-board system would collect air from the atmosphere, from which liquid oxygen would be separated and stored. The liquid oxygen collected then would be used in the final flight phase when the rocket engine burns the collected liquid oxygen and the carried hydrogen to attain orbit. The vehicle would be designed to permit at least a hundred re-entries into the atmosphere.

Dr. M R Suresh, a senior ISRO official, stated that, "The dream of making a vehicle which can take off from a runway like an aircraft, and to return to the runway after deploying the spacecraft in the desired orbit (or Single-stage-to-orbit or SSTO) can be fulfilled only by the availability of more advanced high strength but low density materials so that the structural mass of the vehicle could be reduced considerably from the present levels. The advent of nano-technology could play a deciding factor in developing such exotic materials. However, the material technology available today can realize a Two Stage To Orbit (TSTO) vehicle only and the configuration of the vehicle which is being considered. However, before realizing the RLV-TSTO, it is important to perfect many critical technologies pertaining to hypersonic reentry vehicles. Hence a technology demonstrator vehicle (RLV-TD) is being developed."

A model of the RLV-TD

AVATAR is being developed by India's Defense Research and Development Organization. Air Commodore Raghavan Gopalaswami, former chief of Bharat Dynamics Ltd, Hyderabad, is heading the project. He coined the name and made the presentation on the space plane at the global conference on propulsion at Salt Lake City (USA) on July 10, 2001. Gopalaswami said the idea for AVATAR originated from the work published by the RAND Corporation of the United States in 1987.

At one time,AVATAR had an initial development budget of $5 million allocated for prototype testing. Along with DRDO team development of critical technology components were undertaken by as many as 23 academic institutions (Indian Institutes of Technology, Indian Institute of Science et al.) along with ISRO in India. Both the scramjet engine concept and the liquid oxygen collection process have already undergone successful tests at DRDO and at the IISC. DRDO has approvedfurther testing of the liquid oxygen process and assigned a team to conduct a detailed review of the vehicle’s design.

DRDO planned to build and fly a scaled-down version of AVATAR, weighing 3 tonnes (6,600 lb) at takeoff.The project is headed by Vikram Sarabhai Space Centre in Thiruvananthapuram. The mini AVATAR is to be built by a Hyderabad-based private company called CIM Technologies, project completion data is still not finalized. The prototype will be launched using the PSLV and will demonstrate all technologies used in AVATAR including oxygen collection.

The aerodynamics characterization of the RLV-TD was done by National Aerospace Laboratories.

The AVATAR design has already been patented in India and applications for registration of the design have been filed in patent offices in the United States, Germany, Russia and China.