PSLV - C7 is 44. m tall and weighing 295 tonnes. It was
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In its tenth flight conducted from
Satish Dhawan Space Centre (SDSC) SHAR, Sriharikota, today (January 10,
2007), ISRO’s Polar Satellite Launch Vehicle, PSLV-C7, successfully launched four
satellites -- India’s CARTOSAT-2 and Space capsule Recovery Experiment
(SRE-1), Indonesia’s LAPAN-TUBSAT and Argentina’s PEHUENSAT-1 into a
635 km high polar orbit.
For the first time, a Dual Launch Adopter (DLA)
was used in PSLV to accommodate two primary satellites in tandem. After the final count down, PSLV-C7 lifted off
from the first launch pad at SDSC SHAR, at 9.23 am with the ignition
of the core first stage and four of the six strap-on motors. The
remaining two strap-on motors were ignited at 25 sec after lift-off.
The important flight events included the separation of the
ground-lit strap-on motors, separation of air-lit strap-on motors
and the first stage, ignition of the second stage, separation of the
heatshield at about 121 km altitude after the vehicle had cleared
the dense atmosphere, second stage separation, third stage ignition,
third stage separation, fourth stage ignition and fourth stage cut-off.The
680 kg main payload, CARTOSAT-2, mounted over DLA, was the first
satellite to be injected into orbit at 981.3 sec after lift-off at
an altitude of 639 km. About 45 sec later, DLA with the 6 kg
PEHUENSAT-1 mounted on it, was separated. 120 sec later, the 550 kg
Space capsule Recovery Experiment (SRE-1) mounted inside DLA was
separated and finally, 190 sec later, the 56 kg LAPAN-TUBSAT,
mounted on the equipment bay of PSLV fourth stage was separated.
The four satellites have been placed in a polar
orbit at an altitude of 637 km with an inclination of 97.9 deg with
respect to the equator. The initial signals indicate their normal
health. PSLV is the workhorse launch vehicle of the Indian Space
Research Organisation (ISRO) with nine consecutively successful
flights so far. |
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Since its first successful launch in 1994, PSLV has
launched seven Indian remote sensing satellites, an amateur radio
satellite, HAMSAT, and four small satellites for foreign customers
into 550-800 km high polar SSOs. Besides, it has also launched
India’s exclusive meteorological satellite, Kalpana-1, into
Geosynchronous Transfer Orbit (GTO). PSLV will also be used to
launch India’s first spacecraft mission to moon, Chandrayaan-1,
during 2008.
The 44 m tall PSLV has a lift-off mass of 295 tonne. It is a four-stage launch vehicle with the first and the
third stages as well as the six strap-ons surrounding the first
stage using HTPB based solid propellant. PSLV’s first stage is one
of the largest solid propellant boosters in the world. Its second
and fourth stages use liquid propellants. PSLV’s bulbous payload
fairing has a diameter of 3.2 metre. The vehicle has S-band
telemetry and C-band transponder systems for monitoring its health
and flight status. It also has sophisticated auxiliary systems like
stage and payload fairing separation systems. |
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PSLV was originally designed to put 1,000 kg
class of India’s remote sensing satellites into a 900 km polar SSO.
The payload capability of PSLV has been successively enhanced and in
today’s flight, PSLV-C7, it launched four payloads, in all
weighing 1292 kg in addition to the DLA. Some of the modifications
incorporated in PSLV-C7 compared to the previous flight, PSLV-C6,
are:
1. Use of Dual Launch Adopter
2. Reduction of propellant from 2.5 tonne to 2 tonne in the fourth
liquid propellant stage, PS4
3. Altitude based Day of Launch wind biased steering programme
during Open Loop Guidance
Cartosat-2, the twelfth in the Indian Remote Sensing
(IRS) satellite series, is an advanced remote sensing satellite
capable of providing scene-specific spot imagery. It will join the
other six IRS satellites which are in service -- IRS-1C, IRS-1D,
OCEANSAT-1, Technology Experimental Satellite (TES), RESOURCESAT-1
and CARTOSAT-1. It carries a Panchromatic camera (PAN) to provide
imageries with a spatial resolution of better than one metre and a
swath of 9.6 km. The satellite can be steered up to 45 deg along as
well as across the track. The data from the satellite will be used
for cartographic applications at cadastral level, urban and rural
infrastructure development and management, as well as applications
in Land Information System (LIS) and Geographical Information System
(GIS).
Soon after its separation from the DLA, the two solar arrays of
CARTOSAT-2 were automatically deployed to generate the electrical
power for the satellite. The satellite health is being continuously
monitored from the Spacecraft Control Centre of ISTRAC at Bangalore
with the help of its network of stations at Bangalore, Lucknow,
Mauritius, Bearslake in Russia, Biak in Indonesia, as well as
support from Svalbard ground station in Sweden for the initial phase
of the CARTOSAT-2 mission. Further operations on the satellite like
orbit trimming, checking out the various subsystems and, finally,
switching on the cameras will be carried out in the coming days.
With ISRO Satellite Centre (ISAC), Bangalore, as the lead Centre,
CARTOSAT-2 was realised with major contributions from Space
Applications Centre (SAC), Ahmedabad, LPSC at Bangalore, and IISU,
Thiruvananthapuram. ISTRAC is responsible for initial and in-orbit
operation of CARTOSAT-2. The National Remote Sensing Agency (NRSA),
Hyderabad receives and processes the data from CARTOSAT-2
Space capsule Recovery Experiment
(SRE-1), developed by ISRO’s VSSC and ISAC, is a 550 kg capsule,
intended to demonstrate the technology of an orbiting platform for
performing experiments in micro gravity conditions. After the
completion of the experiments, the capsule will de-orbited after a
few days and recovered. SRE-1 mission will provide valuable
experience in such important fields like navigation, guidance and
control during the re-entry phase, hypersonic aero-thermodynamics
facilitating the development of reusable thermal protection system (TPS),
recovery through deceleration and floatation besides acquisition of
basic technology for reusable launch vehicles.
SRE-1 carries two experiments, an Isothermal Heating Furnace [IHF]
and a Biomimetic (Biomineralisation of Inorganic materials)
experiment. IHF will be operated to perform metallurgical
experiments while Biomimetic experiment will be operated to perform
Biomimetic synthesis. SRE-1 comprises aero-thermo structure,
spacecraft platform, deceleration and floatation system besides the
micro-gravity payloads. It has a sphere-cone-flare configuration
with a spherical nose of about 0.5 m radius, base diameter of 2 m
and 1.6 m height. The capsule is made of mild steel. The parachute,
pyro devices, avionics packages of triggering unit and sequencer,
telemetry and tracking system and sensors for measurement of system
performance parameters are placed inside SRE capsule.
Two days before de-orbiting, SRE-1 will be placed in a
Repetitive Elliptical Orbit. Subsequently, it will be reoriented and
deboost rocket is fired to make it reenter the earth’s atmosphere.
Close loop guidance system is employed during deboost and coasting
phases leading to its recovery. On re-entry, after initial
aerodynamic braking, a parachute system will reduce the touch down
velocity. SRE-1 will splashdown in the Bay of Bengal, east of
Sriharikota coast. A floatation system will keep SRE afloat and
enables its recovery.
SRE-1 is being tracked and monitored by ground stations at
Bangalore, Lucknow, Mauritius, Biak in Indonesia, Bearslake in
Russia, Saskatoon in Canada and Svalbard in Sweden/Transo in Norway.
LAPAN-TUBSAT and PEHUENSAT-1 were launched under commercial
agreements. LAPAN-TUBSAT is a cooperative venture between Indonesian
Space Agency, LAPAN and Technical University of Berlin. It is an
earth observation satellite besides a technical demonstrator in
control systems. The 56 kg LAPAN-TUBSAT carries two Charge Coupled
Device (CCD) cameras with ground resolutions of 5 m and 200 m
respectively. It also carries an experiment for message store and
forward system.
PEHUENSAT-1 is a 6 kg Argentinean nano-satellite meant to
serve educational, technological and scientific fields. PEHUENSAT-1,
developed by University of Comahue of Argentina, AMSAT (Amateur
Satellite Association of Argentina) and Argentina Association for
Space Technology, is intended to provide an experiment platform to
perform amateur radio experiments between colleges and universities
of Argentina.
With its ninth consecutively successful launch today, PSLV
has once again proved its reliability and versatility to orbit
multiple satellites and launch satellites in different types of
orbit. In today’s launch, several improvements to the vehicle and
the Dual Launch Adopter have been proved in flight. .
Courtesy & Source: Indian Space Research Organisation
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