Indian Express(29-06-2006)
http://epaper.newindpress.com/
ISRO to conduct test flight of scramjet
Bangalore: Making a major stride towa rds future space transportation systems,
the Indian Space Research Organisation (ISRO) is planning a test flight of
an integrated scramjet propulsion system in its quest to bring down the launch
costs.
The integrated scramjet propulsion system, comprising air intake, combustor
and nozzle, would be flight tested using a two stage sounding rocket.
In its ongoing research for supersonic combustion ramjet (scramjet), ISRO
had carried out a series of ground tests, realising a stable supersonic combustion
for seven seconds with an inlet mach number of six (six times the speed of
sound).
In the latest issue of ‘Space India’ of the ISRO, J.D.A.Subramanyan, project
director of the air breathing propulsion project at the Thiruvananthapuram-based
Vikram Sarabhai Space Centre, said advanced reusable launch vehicles with
air breathing propulsion would substantially reduce the cost of access to
space, which was about $ 12,000 per kg for launch into near earth orbit.
The cost could be brought down by reducing the vehi cle size and recovering
and reus ing the hardware.
‘‘More importantly, reducing propellant is imperative for low cost access
to space as propellant forms about four fifth of launch vehicle mass at take
off,’’ he said, adding that it formed 78 percent of the mass for space shuttles
and 86 percent for indigenous GSLV.
Subramanyan said that by using air breathing propulsion, the need for carrying
oxidiser could be minimised, if not eliminated, by drawing oxygen from the
air.
But since dense air was available only up to about 50 km altitude, the question
arose regarding the extent of benefit of using air. However, three fourth
of the propellant was consumed by the launch vehicle within this portion
of flight, he said, citing the GSLV example which consumed 75 percent of
the propellant before it reached an altitude of 44 km.
