The origins of the Indian space program can be traced back to 1962,
when the Indian National Committee for Space Research (INCOSPAR) was created under the
auspices of the Department of Atomic Energy (DAE). The early goals of the program were
modest and primarily scientific, related to meteorological and atmospheric investigations
through the launch of sounding rockets. An important milestone was reached on August 15
1969, when the Indian Space Research Organization (ISRO) was formally constituted. ISRO,
in its formative years, was still under DAE. However, when the modern and the more
ambitious phase of the space program began in 1972 -- with the setting up of Space
Commission and Department of Space (DOS) -- ISRO was brought under DOS. The objectives
were now expanded to include advancements in the areas of communication, resources survey
and management, development of satellites, launch vehicles and associated ground systems.
The scientists at the helm of the space program, to their credit, were
well aware that more than three-quarters of Indian populace (at that time) were dependent
on agriculture. Thus, the two primary aims were recognized as the establishment of
independent remote sensing and communications satellite systems with launcher autonomy by
the end of the century. In this context, the comments by Dr. Vikram Sarabhai -- widely
regarded as the father of Indian space program -- are very relevant. He said, "There
are some who question the relevance of space activities in a developing nation. To us,
there is no ambiguity of purpose. We do not have the fantasy of competing with the
economically advanced nations in the exploration of the moon or the planets or manned
space flight. But ……, we must be second to none in the application of advanced
technologies to the real problems of man and society." Today, it can be said that
India is well on the way to realizing its goals.
Since its humble beginnings in the space field, India has made
impressive strides. It became only the seventh nation to achieve orbit capability in July
1980 with the successful launch of its first launch platform, called the Satellite Launch
Vehicle (SLV-3). SLV-3 was carrying aboard an experimental satellite Rohini-1B, which was
also the first satellite to be launched from the Indian soil. In the next two decades,
steady progress was made in the launcher and satellite areas. The requisite technologies
for the more advanced launchers, the Augmented and the Polar Satellite Launch Vehicles
(ASLV and PSLV respectively), were developed. The PSLV is being developed further into the
Geo-stationary Satellite Launch Vehicle (GSLV). The development process is at a critical
stage and a GSLV launch is expected anytime now, which would give India the full range of
satellite launcher capabilities. Further, ISRO has also been highly successful in the
indigenous development of the IRS (Indian Remote Sensing Satellite) and the INSAT-2
(Indian National Satellite) class satellites, freeing India from any foreign dependence
for satellite technology.
In the current paper, the author endeavors to provide a comprehensive
overview of the Indian space program. Particular emphasis will be laid on the
technological and temporal evolution of the launch vehicles from SLV-3 to GSLV and their
associated propulsion systems. Also, the progression of the satellite program from the
Rohini class satellites to the Insat-2 class satellites will be discussed in some detail.
Since, any article on the space program would be incomplete without an insight into ISRO
and its frontal institutions, a brief description of these principle players is provided
towards the end. Finally, the author concludes by looking at the future ambitions of ISRO.
Launchers and Propulsion Systems
Development of suitable launchers for the various remote sensing
and communications satellites is one of the principle aims of the space program. Launcher
and propulsion development represented ISRO’s single largest area of expenditure,
consuming almost half of the annual space budget up to the late 1980s. This shows the
great importance attached to this area in the initial years, compared to other aspects of
the effort such as the satellite development program. Accordingly, launcher capability has
seen a gradual evolution from the all-solid SLV-3 of 1980-83 to the liquid-solid PSLV of
1993-20xx, final step being the liquid-cryogenic GSLV. Thus, the launch program is a true
progression from one launcher to the next more advanced one by utilizing the technology
derived from the previous one. What follows is a description of these various vehicles and
the propulsion systems that drive them.
Foundations for the Launcher Program – Rohini Sounding Rockets
India’s space program began in November 1963 with the launch
of a 2-stage US Nike-Apache sounding rocket from Thumba, near Trivandrum. Production of
indigenous Rohini Sounding Rockets (RSRs) at VSSC created the core of expertise for an
orbital launcher program, beginning with the 75mm dia RH-75. Four Rohini models remain in
service, launched at an average of one a week for meteorology (RH-200), middle atmosphere
(RH-300) and ionosphere (RH-560) investigations from SHAR, Thumba and Balasore. RH-200s
are launched most frequently. For example, 40 were launched with radar chaff during 1987
from Balasore for the Indian Meteorological Dept. The RSR program is centered at VSSC. All
the RSRs employ solid fueled motors. Further technical details of the RSRs are not
relevant at the current stage of India’s space program.
Satellite Launch Vehicle (SLV-3)
The SLV-3 was a 4-stage, solid-fuel (polybutadiene) based light launcher. It weighed
around 17.8 tons and was 22.7 meters tall with a 1 meter diameter. It could place a 42kg
satellite in the Low Earth Orbit (LEO). Its major subsystems are four solid-propellant
rocket motors, interstages connecting the forward skirt of one stage with the rear skirt
of the next stage, inertial guidance and control systems to steer the vehicle along a
predetermined trajectory and a heat shield to protect the fourth stage and the satellite
payload.
SLV-3’s first launch in August 1979, carrying Rohini-1A, was a
failure. However, the three subsequent launches of SLV-3 in July 1980, May 1981 and in
April 1983 carrying Rohini-1B, 2 and 3 were all either completely or partially successful.
Rohini-2 was launched into a orbit 186´ 418 km orbit instead
of the planned 296´ 834 km. All the rockets were launched from
the Sriharikota base in Andhra Pradesh, which is operational since the success of an
RH-125 (Rohini) sounding rocket in October 1971.
SLV-3 |
Stage 1 |
Stage 2 |
Stage 3 |
Stage 4 |
Overall length |
10m |
6.4m |
2.3m |
1.5m |
Prinicipal diameter |
1m |
0.80m |
0.815m |
0.657m |
Propellant mass |
8660kg |
3150kg |
1060kg |
262kg |
Total mass |
10,800kg |
4900kg |
1500kg |
360kg |
Propellant |
PBAN |
PBAN |
HEF-20 |
HEF-20 |
Thrust |
422kN vacuum (mean) |
267kN vacuum (mean) |
90.7kN vacuum (mean) |
26.8kN vacuum (mean) |
No. of motors |
1 (3 segments) |
1 |
1 |
1 |
Burntime |
49sec |
39.9sec |
45sec |
33sec |
Augmented Satellite Launch Vehicle (ASLV)
ASLV, comparable in performance to the US Scout, is a 4-stage (+ 2
strap-ons) all-solid rocket derived by uprating the SLV-3. It weighed around 41 tons and
was 23.6 meters tall with a 1 meter diameter. SLV-3’s 42 kg LEO capability was
augmented to 150kg, largely by adding strap-on boosters derived from the existing stage 1.
Four Developmental (= D) launches were planned. ASLV D-1 carrying SROSS-1 (Stretched
Rohini Series Satellite) failed in May 1987, when stage 1 did not ignite following
strap-on burnout. The investigation board attributed it to either a loose connection or a
random failure. The second SROSS-2 was also lost aboard ASLV-D2 in July 1988 when stage 1
ignited after 49.8 sec instead of 49.5 sec following strap-on burnout at 49.2 sec. It was
determined that wind shear prevented the control systems from converging the guidance and
the upper stages broke away. Resulting modifications included a redesigned autopilot and
motor changes to reduce dynamic pressure. The third, ASLV-D3 was launched in May 1992
carrying the SROSS-C and it was a partial success. It achieved orbit but stage 4 did not
fully spin up, resulting in a low perigee. However, this flight validated all the
corrective actions in the design of ASLV. The final developmental flight ASLV-D4 with
SROSS-C2 was successful in 1994.
ASLV |
Strap-ons
(AS0) |
Stage 1
(AS1) |
Stage 2
(AS2) |
Stage 3
(AS3) |
Stage 4
(AS4) |
Overall length |
11m |
10m |
6.35m |
2.44m |
1.4m |
Prinicipal diameter |
1m |
1m |
0.8m |
0.815m |
0.655m |
Propellant mass |
8637kg |
8900kg |
3200kg |
1060kg |
317kg |
Total mass |
11,600kg |
11,800kg |
4400kg |
1710kg |
512kg |
Propellant |
HTPB |
HTPB |
HTPB |
HEF-20 |
HEF-20 |
Thrust |
440kN mean, 580 max |
502.6kN mean, 643 max |
218kN mean, 260 max |
63kN mean, 88.7 max |
26.2kN mean, 34kN max |
No. of motors |
2 (3 segments) |
1 |
1 |
1 |
1 |
Burntime |
47sec |
48.3sec |
36sec |
44sec |
32sec |
- ASLV Strap-ons (AS-0)
The two strap-ons that ASLV has, employ the same motor as its main
stage 1. Further, the motor for both the strap-ons and stage 1 of ASLV is derived from the
stage 1 of SLV-3. However, the nozzles on the strap-on motors are canted at 9 degrees,
while those on the main stage are not.
ASLV Stage 1 (AS-1)
ASLV’s stage 1 is an uprated version of SLV-3’s first
stage. Stage 1 ignites at 49.5 sec following strap-on burnout at 49.2 sec (timings could
vary and depend on realtime decision). On ASLV-D1, stage 1 failed to ignite and on D2, low
control gain contributed to vehicle break-up, as described before. The nozzles in stage 1
incorporate secondary injection ports for TVC.
ASLV Stage 2 (AS-2)
Again, stage 2 motor is an upgraded version of SLV-3’s stage 2
motor. Certain changes in the solid fuel composition were made. The same grain
configuration as SLV-3 was retained, but the aluminum content was raised from 12% to 18%
accompanied by a thickening of carbon phenolic ablative material to combat increased
erosion.
ASLV Stage 3 (AS-3)
This is the only ASLV motor applied directly from its predecessor
SLV-3.
ASLV Stage 4 (AS-4)
Again an upgraded version of SLV-3 stage 4. Stage mass reduction was achieved with
Kevlar 49 replacing glass fibre reinforced plastic as the casing material. Propellant mass
was increased 45kg by slight case stretching and was compensated for by recontouring to a
shorter nozzle. This stage failed to spin up fully on the partially successful ASLV-D3,
yieling low perigee and short satellite life.
Polar Satellite Launch Vehicle (PSLV)
PSLV represents the first stage in acquiring launcher autonomy for
applications satellites. It weighs around 283 tons and is 44.18 meters tall with a 3.2
meter diameter (5.1m base circle with strap-ons). It is ISRO’s workhorse for remote
sensing missions. It can place a 1ton IRS Earth Resources Satellite in the 904km
Sun-synchronous orbits from Sriharikota. Due to Sriharikota’s geographical location,
a north or south polar launch from Sriharikota is not feasible due to the presence of
heavily populated areas (India and Sri Lanka). Thus, PSLV is constrained to be launched at
azimuths <= 140degrees, forcing PSLV to execute a 55degrees yaw maneuver after 100sec
to reach a Sun-synchronous path. Payload could be 1.6ton without this launch restriction.
Upgradation of Balasore rocket station would eliminate all the above restrictions and has
been under study for sometime now. Notably, PSLV has the capability to launch a 3t payload
into an orbit of 1000km apogee and 1000km perigee.
PSLV possesses only a 450kg GTO capability, but offers potential for
the development of a Geosynchronous SLV to place 2.5ton satellites into GTO. It has been
designed such that substantial payload increases can be achieved with minor modifications.
The first stage, consisting of 5 segments, can be augmented by an additional segment,
increasing the thrust of the booster. The 6 small strap-on motors forming the zero-stage
can be replaced by 2 large ones. Further, by using a larger tank, the second stage can
carry a larger loading of the propellant and thereby substantially increasing the payload
capability. The two upper stages can be replaced by a cryogenic stage that would give PSLV
a GTO capability. Thus, the adaptability of PSLV and its various stages give ISRO the
ability to develop the GSLV.
PSLV employs an unusual combination of liquid and solid stages. It uses
the first Indian developed liquid motors for stages 2 and 4. Stage 1 employs a solid motor
with six ASLV strap-ons clustered around it. Stage 2 employs a single liquid engine,
designated as Vikas, which is developed from Viking of Ariane. The aluminum interstages
and fairing are manufactured by HAL in Bangalore.
The first developmental flight of PSLV-D1 was conducted on 20 Sep 1993.
The vehicle performed well, but an uncorrected pitch problem occurred after stage 2
separation. As a result, it attained an altitude of only 340km after stage 3 burnout
instead of the planned 414km. After investigations, the cause was found to be a minor
software error. PSLV would have attained orbit without it. Stage 2 engine burnout occured
3.7sec before stage 3 ignition. Then, the recontact between the stages -- because of two
failed small solid retros – produced a pitch disturbance that exceeded the preset
limit. PSLV would have removed it if not for the software error in the control loop. With
the modified software, PSLV-D2 was successful, followed by PSLV-D3 in March 1996. The
government has given approval for six further (PSLV C1-6; C = Continuation) flights after
the first three (D1-D3; D = Development).
PSLV |
Strap-ons
(PSOM/S9) |
Stage 1
(PS1/S125) |
Stage 2
(PS2/L37.5) |
Stage 3
(PS3/S7) |
Stage 4
(PS4/L2) |
Overall length |
10m |
20.3m |
11.5m |
3.5m |
2.6m |
Prinicipal diameter |
1m |
2.8m |
2.8m |
2m |
1.34m |
Propellant mass |
8920kg |
129,000kg |
37,500kg |
7200kg |
2000kg |
Total mass |
10,930kg |
160,200kg |
43,000kg |
8300kg |
2920kg |
Propellant |
HTPB |
HTPB |
UDMH/N2O4 |
HEF-20 |
MMH/N2O4 |
Thrust |
440kN mean,580 max |
3463kN mean,4600 max |
725kN mean |
243.2kN mean,386 max |
14kN (incl. both engines) |
No. of motors |
6 (3 segments each) |
1 (5 segments) |
1 |
1 |
2 |
Burntime |
47sec |
103sec |
149sec |
73.1sec |
425sec |
- PSLV Strap-ons Motors (PSOM)
They are almost identical to the ASLV strap-ons. For PSLV, the
secondary injection TVC systems are deleted on one ground-lit and three air-lit strap-ons.
A monolithic version was tested November 17 1994 and was introduced on PSLV-C1. Payload
gain with version is marginal, but the design facilitates faster production/handling and
improves reliability. To maximize the payload, the ignition sequence of PSOM’s is
designed such that two PSOM’s are ignited along with the first stage at liftoff and
other four PSOM’s are ignited 29sec later.
- PSLV Stage 1 (PS-1)
PS-1 is the most powerful model used by ISRO among the motors
employed for SLV-3, ASLV and PSLV. It was successfully static fired for the first time on
October 21 1989 and a second one was carried out March 23 1991.
- PSLV Stage 2 (PS –2/L37.5)
PS-2 employs India’s first large liquid propellant rocket
engine, Vikas, which is based on the Viking-IV engine technology of SEP, France. The Vikas
differs from Viking mainly in its larger propellant load and longer burn time. The engine
achieved its first full-duration 150s firing in Janurary 1988 on the Principal Test Stand
at the Liquid Propulsion Test Facility, Mahendragiri. It completed the first integrated
stage test on March 21 1990 and qualification was completed in Oct 1992. A successful 200s
run in 1995 tested the new indigenously developed silica-phenolic throat, designed to
withstand the operational 1300 degrees Celsius.
- PSLV Stage 3 (PS -3)
This is ISRO’s most advanced solid propellant motor, designed
for a 0.915 mass fraction and the first to adopt a submerged flex nozzle design for TVD.
Stage 3 is suspended inside a 2.8m dia fairing from the heatshield’s boat-tail.
Casing materials include wound Kevlar filament, EPDM insulation and aluminum forgings for
skirt and end-opening fittings.
- PSLV Stage 4 (PS –4/L2)
PSLV’s final stage consists of two identical, pressure-fed
bipropellant engines, gimballed up to +/-3degrees in two orthogonal planes by a closed
loop servo control system to provide stage pitch, yaw and roll control during thrust
phase. The integrated stage was first tested at Mahendragiri on September 27 1989,
beginning a program that included two full duration trials and a demonstration of restart
capability.
Geosynchronous Satellite Launch Vehicle (GSLV)
Development of GSLV represents the culmination of India’s efforts
to achieve complete launcher autonomy. It will incorporate the flight proven solid and
liquid stages of the PSLV. The first developmental test flight is expected to take place
soon and if successful, would herald India into the select club of nations that possess
this capability. The first developmental flight, GSLV-D1, will carry an experimental
communications satellite GSAT-1 weighing about 1.53tons. GSLV belongs to the Ariane class
of launchers, capable of orbiting 2.5t Insat-2 class satellites. Some 500 configurations
were reduced to four during 1986-88, divided equally between solid and liquid cores and
both with solid and liquid strap-ons. GSLV will have 4 liquid strap-ons instead of the six
solid ones found on the PSLV. It is, however, said that the initial version of GSLV will
use the PSLV strap-ons. The two upper stages on PSLV will be replaced by a single
cryogenic stage. The vehicle is comparable in performance to Ariane 44L except for the
lower performance of solid stage 1.
In Jan 1991, ISRO signed a Rs.2350 million agreement with Glavkosmos
for the supply of two Russian cryogenic stages for the initial launches. Technology
transfer was also part of the agreement, to be used for the production of subsequent
stages in India. The KUB-7.5 76kN KB Khimmach engine was originally developed to power
Russia’s manned lunar lander in the early 1970s. The same engine will power the
Proton rocket’s upgraded 4th stage. However, United States -- under the
pretext of violation of Missile Technology Control Regime, to which Russia is a signatory
-- forced the Russians to formally abandon the agreement in August 1993. Later in the
year, Indian government approved plans for an indigenous cryogenic stage. Critics contend
that the US action to stop the Russian sales actually created another source of such
engines and that a resentful India may not be restrained by efforts to sell its technology
overseas.
The course of engine development was not easy for India. LPSC’s
(the contractor for this development) first attempt at firing a 10kN LOX/LH2 engine ended
with an explosion at ignition in July 1993. LH2 became available in India only after a US
company built a plant at Mahendragiri towards the end of 1992. India and Russia reached an
agreement in January 1994 for Glavkosmos to deliver the first to deliver the first of
three engines in 199. The contract was increased in early 1995 to seven engines. In
February 2000, the first test of India’s home-grown cryogenic rocket had to be
prematurely terminated because of a hydrogen leak. ISRO, in a press release, said that the
firing was aborted 15 seconds after ignition instead of the planned 30 seconds. However,
ISRO scientists expressed confidence that the problem could be quickly fixed.
The GSLV utilizes Insat 2’s 119kg (dry mass) unified bipropellant
liquid propulsion system made up of a single 440 N Liquid Apogee Motor and two redundant
networks of 8´ 22 N RCS thrusters for final orbital placement.
The engines, pressure regulator, check valve, fill, drain and vent valve, pyro valve and
pressure transducer were developed indigenously; the tanks, gas bottles, filters and latch
valves were procured from foreign suppliers. It is estimated that India’s first
cryogenic upper stage can handle 5ton payloads into GTO and Sun-synchronous orbits and
15ton into LEO. The indigenous GSLV will also create a planetary capability. Missions to
Mars, Mercury and Venus are under consideration.
GSLV |
Stage 0
GS0/L-40 |
Stage 1
GS1/S-125 |
Stage 2
GS2/L-375 |
Stage 3
CS/GS3 |
Overall length |
19.7m |
20m |
11.5m |
8.72m |
Prinicipal diameter |
2.1m |
2.8m |
2.8m |
2.8m |
Propellant mass |
4 x 40,000kg |
129,000kg |
37,500kg |
12,500kg |
Total mass |
4 x 45,500kg |
156,000kg |
43,000kg |
14,600kg |
Propellant |
UDMH/N2O4 |
HTPB |
UDMH/N2O4 |
LOX/LH2 |
Thrust |
4 x 735kN (mean) |
4860kN (mean) |
725kN |
75kN |
No. of engines |
1 |
1 motor (5 segments) |
1 |
1 |
Burntime |
158sec |
93sec |
150sec |
800sec |
- GSLV Liquid Strap-ons (L40)
PSLV’s liquid Vikas engine is being adapted for this purpose.
- GSLV Stage 1 (S125) and GSLV Stage 2 (L37.5)
The specifications are same as that of PSLV stage 1 and stage2.
- GSLV Stage 3 (Cryogenic stage)
There are two configurations for the cryogenic stage of GSLV: C14
and C25. The numbers after C refer to the propellant mass in metric tons.
Like even the PSLV, GSLV presents substantial scope for upgradation to
provide higher payloads up to 6tons into GTO. The various configurations and their
payloads are tabulated below:
Vehicle Configuration |
Payload into GTO |
2S150 + S150 + L37.5 + S7 |
2450kg |
(8S9 + S150) + L37.5 + C14 |
2,250kg |
2S150 + S150 + L37.5 + C14 |
5000kg |
2S150 + S150 + L55+ C25 |
5800kg |
In the above table, S, L and C stand for solid, liquid
and cryogenic stages respectively. The number before the alphabet indicates the number of
motors and the number after indicates the propellant mass in metric tons. However,
according to ISRO, GSLV-D1 will have the following configuration: S125 (+ 4 x L40) + L37.5
+ C12, which will have a payload of 1.53tons.
Satellites
The saga of Indian satellite program began on April 19 1975, when
Aryabhatta was launched by the Soviet SL-8 from Kapustin Yar. In the last couple of
decades, India has achieved complete indigenous capabilities to build both the remote
sensing and communications satellites. This is also reflected in the current budgetary
allocations for the satellite development/(IRS, Insat ops), which equal or even exceed
that for the launcher program. The program has evolved (i) from the experimental remote
sensing satellites, Bhaskara-I and II to the world’s most advanced IRS class
satellites and (ii) from the experimental APPLE (Ariane Passenger Payload Experiment)
communications satellite to the advanced Insat-2 series of satellites. This evolution, as
we will see, has not been easy and was beset with frequent problems that were overcome
with sheer grit and determination. A brief description of the important classes of
satellites launched follows.
Aryabhatta
This was the first Indian satellite launched by an Intercosmos
rocket of the erstwhile USSR. It was designed for 6 months and carried three payloads, one
each for X-ray astronomy, solar physics and aeronomy. Control was to have been handed over
to Indian scientists on day 3, but the transformer failed and only a few days of useful
life was obtained.
Bhaskara-I and II
They were both experimental remote sensing satellites launched on
June 7, 1979 and November 20, 1981 by Intercosmos rockets. They carried two TV cameras,
one in visible band and the other in near-infrared band, and a 3-frequency passive
microwave radiometer. Useful ocean and land surface data were received from Bhaskara-I,
but the cameras malfunctioned. Bhaskara-II was declared operational after receipt of more
than 300 TV images of Indian subcontinent. House keeping telemetry was received until
re-entry on February 17 1989.
Stretched Rohini Series Satellites (SROSS-1, 2, C and C2)
SROSS-1 could not be orbitted succesfully due to ASLV-D1’s
failure. The SROSS series of low-cost 150kg satellites is designed to carry scientific and
remote sensing payloads of 15-35kg. ISRP postponed the launch of SROSS 1 from late 1985 to
early 1987 mainly due to problems with ASLV’s stage 1. SROSS 1 was principally
intended to monitor launcher performance and carried a battery of inertial measurement
instruments for this purpose. SROSS 1 had on octogonal body and was powered by solar cells
on each face and deployed panels. It also carried two retro-reflectors for laser tracking
and ISRO’s 30-1000 keeV Gamma-ray burst experiment.
SROSS-2 was also lost in the failure of ASLV-D2. However, SROSS-C and
-C2 were launched successfully by ASLV-D3 and ASLV-D4 in May 1992 and 94 respectively.
They were lighter than their predecessors at 106kg. SROSS C attained only a lower than
intended perigee (and hence a shorter life) due to problems with stage 4 of ASLV-D3. But,
mission specifications were declared to be met. SROSS-C2 is still providing valuable
scientific data.
Indian National Satellite System (Insat)
The Insat system provides India with a unique geostationary
platform for simultaneous domestic communications and earth observation functions. The
four first generation Insat-1 series of satellites were all US and launched by either US
or European vehicles. However, the more advanced Insat-2 class satellites are indigenously
produced and it is envisaged that the latter members of this series would be carried by
India’s own GSLV. The Insat system is a joint venture of India’s Department of
Space, Dept of Telecom, Indian Met Dept, All India Radio and Doordarshan. The satellites
are handled from the Insat Master Control Facility (MCF) at Hassan, Karnataka.
Insat 1
The Insat 1 system was envisaged to comprise two multi-purpose
satellites, each providing two high power TV broadcast and 12 telecom national coverage
transponders, in addition to meteorological services. Principal applications of Insat-1
satellites include domestic communications on C-band, one S-band channel dedicated to
direct TV broadcast and others to disaster warning etc. Ultimately, it consisted of 4
satellites, all built by Ford Aerospace of US. Unfortunately, all the four satellites were
beset with problems, either in their manufacturing/functioning or with launchers. Insat 1A
was launched by US Delta rocket from Cape Canaveral in April 1982, but was abandoned the
following September when its altitude control propellant was exhausted, short of its 7
year life. An insurance payment of about $70 million has been reported. Insat 1B was
launched by the shuttle in August 1983. It almost the same fate as its predecessor. Video
recordings suggested that it might have been struck by Orbiter debris during release,
though this could not be confirmed. It was not until mid-September that Ford and Indian
controllers at Hassan’s MCF succeeded in deploying its solar array. Full operation
was achieved in October. It continued operating satisfactorily into 1990 with all its
two-way voice circuits in use. It was relegated to spare status in July 1990 by Insat 1D.
Insat 1B was responsible for extending TV coverage to 75% of India’s population (90%
area) and also enabled floods and cyclones to be forecast. 1B was removed from GEO in Aug
1993. Insat 1C was launched in July 1988 by Ariane. Like many other nations, India has
suffered from the US shuttle-down, and despite NASA’s offer of a high priority switch
from the shuttle to a Delta rocket, India opted for the Ariane launch. A power system
failure removed half of the communications capacity, although the met services remained
unaffected. However, 1C lost earth link in November 1989 and was abandoned. Failed 1C
reportedly fetched insurance payouts of about $70 million. Insat 1D had no better luck
that its predecessors. It is similar to 1B with expanded battery and propellant
capacities. Launch was planned for 29 June 1989, but on June 19 it was seriously damaged
when a 34kg hook fell 10m directly on to it. The fully insured satellite was repaired by
Ford Aerospace at a reported cost of $10million. It also suffered $150,000 damage during
the October 1989 Californian earthquake. Finally, it was launched on a Delta in June 1990.
Insat 2
The DoS forged ahead with the Insat 2 indigenous satellite
following approval of funding in April 1985. Initially, the DoS sized the Insat 2 to fit
aboard the space shuttle, but the continued launch delays associated with the Challenger
accident forced a redesign of the satellite so it could fit on the Ariane. India is now
within the reach of achieving its primary goal of complete space communication autonomy.
So far, 5 Insat 2’s (2A-2E) have been launched, all by the French Ariane. The number
of C-band transponders is increased to 18 (six at extended C-band) and 406 MHz transponder
for distress beacon detection.
IRS
The Indian Remote Sensing satellite system is India’s maiden
indigenous dedicated earth resources satellite and is part of the National Natural
Resource Management System. In the 1988-2000 period, over 12 satellites have been launched
into the polar orbit. The IRS now also perform environmental monitoring, with an emphasis
on oceanography. They place India on a strong footing not only to fulfill its own
application needs, but also to corner a significant portion of the global commercial
market. In fact, EOSAT -- a US company -- signed an agreement with ISRO to distribute IRS
data globally. EOSAT expects that within a 5 year period, IRS satellites would be the
source of majority of its imagery.
ISRO Centers
The Department of Space has, over the years, built up a strong
R&D and technology base with the necessary infrastructure and manpower for
implementing the space program. In addition to the various ISRO centers, a number of
private organizations have also chipped in by manufacturing important components for the
launchers, satellites and ground control systems. Some of the important centers and their
functions are described below:
Vikram Sarabhai Space Center (VSSC)
VSSC, located around the village of Thumba near Thiruvananthapuram,
is ISRO’s largest center. It is the lead development center for the various Rohini
sounding rockets and the country’s indigenous satellite launchers: ASLV, PSLV and
GSLV. The Solid Propulsion Group, a part of VSSC, oversees ISRO’s solid motor
development program for its various rockets. However, the primary Solid Propellant Space
Booster Plant (SPROB) is located at SHAR center on Sriharikota island, along with the
Vehicle Assembly Static Test and Evaluation complex (VAST) for solid motors.
Sriharikota Range (SHAR)
SHAR, based at Sriharikota in Andhra Pradesh, is ISRO’s main
launch center for its satellite launcher vehicle series. The ASLV orbital launcher is
integrated vertically, beginning with the motor and sub-assembly preparations in the
Vehicle Integration Building (VIB) and completed on the pad within the 40m tall Mobile
Service Center. The PSLV launch was commissioned during 1990. The 3000ton 76.5m high
Mobile Service Tower (MST) provides the SP-3 payload cleanroom between 41-62m. MST is
rolled back 180m launch. The 52m umbilical tower is an open steel structure next to the
launch pedestal. The Launch Control Center is located 6km away and the Checkout Terminal
Room is next to the pad. A second launch pad is also under construction.
Liquid Propulsion Systems Center (LPSC)
LPSC is responsible for the development of the liquid and cryogenic
propulsion stages in PSLV and GSLV. LPSC is gaining greater importance as liquid engines
are being introduced in India’s main orbital launchers and with the increasing size
of indigenous satellites. Important achievements include development of 720kN Vikas PSLV
stage 2 liquid engine and the dual engined stage 4. However, the most important current
project is the development of cryogenic upper stage for GSLV.LPSC’s test facilities
are located at Mahendragiri. Vikas’ Principal Test Stand (PTS) was commissioned
during 1987 and used in January 1988 for the engine’s first full duration 150sec test
firing.
Antrix
Antrix (from the Sanskrit word "Antariksha" meaning
Space) is the commercial arm of ISRO, responsible for the global marketing of IRS
satellite data products, through Space Imaging USA. It forms a stable and growing activity
for ISRO. As a result of this partnership, the network of ground stations for
receiving/processing IRS data has seen a steady growth and currently ten stations around
the world receive IRS data. The successful multiple satellite launch of IRS-P4 (Oceansat),
Korean satellite (KITSAT-3) weighing 100kg and the German satellite weighing about 50kgs
by PSLV-C2 on May 26, 1999 heralded India’s entry into the commercial launch market.
The company now earns valuable foreign exchange for the country.
Conclusions
In the course of last 3-4 decades, Indian space program has truly
come of age and has attained the necessary critical mass that could propel it into the
select league of nations with a whole range of indigenous manufacturing capabilities from
Insat class satellites to GSLV class vehicles. However, this maturing of the space program
has been an arduous one as indicated by the multiple failures of its satellites as well as
launch vehicles. Refusal of technology by western nations at regular intervals has also
hampered the program. It is estimated that the sanctions imposed by the US in 1993 and the
subsequent scuttling of the cryogenic engine technology transfer from Russia has put back
the GSLV program by at least 4 years. However, the first GSLV test flight is around the
corner and when successful would be an epoch-making event in the Indian space program.
After the nuclear tests in June 1998, the western economies again imposed sanctions on
India. But, currently, every part of India’s space launchers is being or can be
indigenously manufactured. The evolution of India as a space nation has not been taken
kindly by advanced space nations, who perceive India’s cheap launchers as a potential
threat to their commercial niche. Added to these economic considerations is the fact that
India is said to have the second best launching site in the world at SHAR, after the
Kourou Islands launch base of France. The recent canceling of a satellite launch contract
with ISRO by Taiwan under US pressure betrays a certain nervousness on the part of these
nations to the emergence of India as a space power.
In addition to the development of GSLV, ISRO is also forging ahead with
its INSAT-3 series of satellites. Recently, it has signed contracts with Arianespace for
the launch of INSAT-3A and -3E satellites. Due to the loss of ISRO’s crucial INSAT-2D
satellite three years ago, INSAT-3B was launched ahead of 3A on March 22 2000 to meet
industry’s growing need for transponders. ISRO has plans for launching INSAT-3C in
mid-2001. ISRO is also exploring the feasibility of launching an unmanned mission to moon.
ISRO Chairman, Dr. K. Kasturirangan noted that PSLV could send an orbiter weighing 350kg
to the moon or a 500kg fly-by mission.
References
- Janes Spaceflight Directory/Janes Space Directory, 1987-2000.
- www.isro.org
- http://www.bharat-rakshak.com/SPACE
- http://www.fas.org/spp/guide/india/index.html
- http://www.boloji.com/india/isp.htm
- http://www.meadev.gov.in/science/space.htm
- "International Reference Guide to Space Launchers" by Steven Isakwitz, AIAA
publication.
- Communications with Mr. D. Ramana and Mr. Rupak Chattopadhyay.
The author wishes to gratefully acknowledge the references and
guidance provided by D. Ramana and Rupak Chattopadhyay.
