Indian Space Research Organisation (ISRO) is gearing for
five launches a year from its Sriharikota spaceport, ISRO
chairman G Madhavan Nair announced immediately after the
successful GSLV-F04 launch on 2 September. There will
be another GSLV launch next year, he said.
would also be two more launches of the Polar Satellite
Launch Vehicle (PSLV) this year, he said, but the details
of what satellite they would put in orbit were yet to
be worked out.
about ISRO''s plans to enter the international satellite-launch
market, Nair told reporters that ISRO was looking at capturing
a modest five to 10 per cent of the mid-range satellite
segment of 2,000 kg plus in the next five years.
Sridhara Murthi, executive director of the Antrix Corporation,
said he had received a number of inquiries for launching
satellites, particularly by the under-development GSLV-Mark
III, which is being designed to put into orbit satellites
weighing more than 3.5 tonnes. Antrix Corporation is the
marketing agency of the Department of Space.
lighter, greener GSLV
To gain a competitive edge in the global satellite launch
market, the Indian Space Research Organisation (ISRO)
is taking steps to cut rocket costs, by cutting the vehicle
weight and increasing its fuel economy.
Indian space agency flies two rockets, the PSLV and the
three-stage GSLV. The former places satellites in the
polar orbit and the latter in the geo-synchronous transfer
orbit. While a fully loaded PSLV costs around Rs 80 crore
($19.7 million), it costs nearly double the amount to
build a GSLV.
objective is to reduce the vehicle''s structural weight,
bring in modular assembly of components, use new engines
and increase the fuel economy. Like automobile manufacturers,
ISRO has started to source complete sub-assemblies from
suppliers instead of individual components, so that the
cost and time required to build its rockets is reduced.
It will take ISRO a number of years to come up with a
reusable launch vehicle, so cutting costs is importance
on the same platform, PSLV and GSLV have several common
components as well as the fuel, except the cryogenic stage
in GSLV. The increase in the number of launches has helped
ISRO to keep the rocket costs down.
reduce the rocket''s structural weight and cost, ISRO is
switching over to non-metallic components and indigenous
materials like aluminium and titanium alloys. Indigenously
designed avionics that will be put into operation next
year weigh 185 kg, lighter than the present navigation
space agency is also trying to reduce the fuel stages
to reduce the rocket weight. The GSLV Mark III model to
carry a four tonne payload will have a reduced fuel stage.
is developing a strap-on motor called PSOM-XL measuring
13.5 metres with a capacity to carry 12.4 tonnes of solid
propellant. Presently the six strap-on motors hugging
the PSLV''s core rocket each carry 9 tonnes of fuel.
future plans include a three stage PSLV to ferry 500 kg
satellites for low earth orbit, a new 229-tonne ''core
alone'' configuration that can carry 1,100 kg satellites
into sun synchronous orbit (SSO), and a vehicle to carry
1,900 kg satellites into SSO by increasing the fuel in
the stage two and improving the thrust power.
''core alone'' PSLV, without strap-on motors, has already
started flying. In April it carried Agile, a 352 kg Italian
satellite. Shortly an Israeli satellite, Polaris, will
be sent up in a core alone PSLV.
is also developing air-breathing ramjet engines that would
use atmospheric oxygen and burn it with on-board fuel.
At present, all rockets worldwide carry liquid oxygen
to burn their fuels in the relative vacuum of the upper
atmosphere and space.
much as 45 to 50 per cent of the cost of the rocket is
fuel, which is why ISRO is testing cheaper alternatives.
The present fuel costs around Rs2,500 ($61.50) per tonne.
The space agency is also considering semi-cryogenic fuel
using highly purified kerosene and liquid oxygen
as oxidiser costing Rs20 per kg.
effort to build an indigenous cryogenic stage is also
progressing well. In August, the cryogenic stage was test
fired on the ground for eight minutes at ISRO''s liquid
propulsion test facility at Mahendragiri, Tamil Nadu.