The Indian Space Research Organisation (ISRO)
is testing the gas motor which is fitted in the
second stage/engine powered by liquid fuel for
high temperature tolerance levels.
The test has forced ISRO to postpone the launch
of its remote sensing satellite Resourcesat-2
and two other payloads by nearly a month. Remote
sensing satellites like Resourcesat send back
pictures and other data for various uses. India
is a major player in providing such data in the
The rocket was scheduled for launch mid-Feb.
According to ISRO officials, the gas motor powers
the rocket's second stage control actuators for
maneuvering the engine's nozzle - the process
is called gimballing. The process enables the
rocket to maintain a steady course on its way
The motor is powered by the hot gases tapped
from the rocket.
"During earlier PSLV rocket launches, we
had noticed the temperature of the hot gases at
the motor inlet being higher by 20-30 percent
while the expected temperature is around or less
than 300 degree celsius," an ISRO official
ISRO officials said the space agency's chairman
K. Radhakrishnan wanted to be sure about the parameters
of the rocket's subsystems as he was of the view
that ISRO cannot afford another failure and that
too involving the PSLV rocket.
ISRO's commercial arm Antrix Corporation is earning
a sizeable sum, launching third-party satellites
using PSLV rockets.
The Indian space agency's last two missions involving
its heavy rocket - Geosynchronous Satellite Launch
Vehicle (GSLV) - ended in failures, resulting
in a total loss of around Rs.600 crore - cost
of two rockets and two satellites.
ISRO will be using PSLV to launch a communication
satellite till the space agency stabilises its
GSLV rocket that can sling much heavier satellites
According to ISRO officials, the temperature
tolerance levels of the gas motor is being tested
in a power generation company near here.
ISRO opted to test the gas motor's heat tolerance
limits as that will be quicker than redesigning
the rocket's engine to bring down the gas temperature.
"Up to 300 degree celsius we can test the
component at ISRO's centre in Thiruvananthapuram.
We do not have super heated steam generators to
test the temperature tolerance levels above that
levels," an official said.
According to him, the test results have been
satisfactory till now as the motor tolerated temperature
up to 370 degree celsius.
The test results will be studied and the final
call on the rocket's launch carrying remote sensing
satellite Resourcesat-2 is expected to be taken
Feb 28 by Radhakrishnan.
ISRO officials said around 20 days' time is required
to test the rocket's subsystems after the launch
If the permission is given on Mar 1, ISRO would
require 20 days more to make the rocket and the
satellite ready for launch.
Meanwhile, the fully assembled PSLV rocket is
standing tall at the Sriharikota launch centre,
around 80 km from here. All the three satellites
are also at the rocket launch pad.
India has the largest constellation of remote
sensing satellites in the world providing imageries
in variety of spatial resolutions from better
than a metre ranging up to 500 metres.
The remote sensing satellites that are operational
are -- Cartosat-2B, Oceansat-2, RISAT-2, Cartosat-2A,
IMS-1, Cartosat-2, Resourcesat-1 and TES.
For some time, Resourcesat-2 and Resourcesat-1
would work together before the latter would go
Launched in 2003, Resourcesat-1 has outlived
its original mission life of five years.
Compared to Resourcesat-1, the multispectral
swath of Resourcesat-2 has been enhanced from
23 km to 70 km based on user needs.
Suitable changes, including miniaturisation in
payload electronics, have also been incorporated
The other remote sensing satellites that ISRO
plans to launch are RISAT, Megha-Tropiques, INSAT-3D,
Astrosat -- astronomy satellite to observe celestial