|
PSLV
Launches CARTOSAT-1 In its ninth flight conducted on May 5, 2005, ISRO’s Polar Satellite Launch Vehicle, PSLV-C6, launched India’s remote sensing satellite, the 1,560 kg CARTOSAT-1, along with a 42.5 kg piggyback satellite, HAMSAT, into a polar Sun Synchronous Orbit (SSO) of 632 km apogee and 621 km perigee. For the first time, the state-of-the-art Second Launch Pad (SLP) at Satish Dhawan Space Centre (SDSC) SHAR was used for a launch. President of India, Dr A P J Abdul Kalam, who had dedicated SLP to the nation the previous evening, witnessed the successful launch from the Mission Control Centre. PSLV, initially designed to place 1,000 kg class Indian Remote Sensing (IRS) satellites into 900 km polar SSOs, has been upgraded to the present capability of 1,600 kg into 618 km polar SSO. The improvements over successive flights have been achieved through increased propellant loading in the stage motors, employing composite material for the satellite mounting structure and changing the sequence of firing of the strap-on motors.
At the end of final count down, the 44.4 metre tall, 295 tonne PSLV-C6 lifted off from SDSC SHAR, Sriharikota at 10:15 am IST 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 seconds 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 payload fairing 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. After these events, CARTOSAT-1 was successfully separated from the fourth stage 1078 seconds after lift-off. Forty seconds later, HAMSAT was also separated from the fourth stage equipment bay. Both the satellites were placed in a polar SSO at an altitude of 632 x 621 km with an inclination of 97.8 deg with respect to the equator. The solar panels of CARTOSAT-1 were deployed soon after its injection into orbit. In its present configuration, the 44.4 metre tall, 295 tonne PSLV has four stages using solid and liquid propulsion systems alternately. The first stage carries 138 tonne of Hydroxyl Terminated Poly Butadiene (HTPB) based solid propellant. The booster develops a maximum thrust of about 4,762 kN. Six strap-on motors, each carrying nine tonne of solid propellant and producing 645 kN thrust surround the first stage. The second stage employs indigenously built Vikas engine and carries 41.5 tonne of liquid propellant — UH25 as fuel and Nitrogen tetroxide (N2O4) as oxidiser. It generates a maximum thrust of about 800 kN. The third stage uses 7.6 tonne of HTPB-based solid propellant and produces a maximum thrust of 246 kN. The fourth and the terminal stage of PSLV has a twin engine configuration using liquid propellant. With a propellant loading of 2.5 tonne (Mono-methyl hydrazine and Mixed Oxides of Nitrogen), each of these engines generate a maximum thrust of 7.3 kN. The 3.2 m diameter metallic bulbous payload fairing of PSLV protects the spacecraft during the atmospheric regime of the flight. With eight consecutively successful flights so far, PSLV has proved itself as a reliable workhorse. It has demonstrated multiple satellite launch capability having launched four small satellites for international customers besides nine Indian satellites. PSLV was used to launch ISRO’s exclusive meteorological satellite, KALPANA-1, into a Geosynchronous Transfer Orbit in September 2002. The vehicle will be used to launch a spacecraft for India’s first mission to Moon, Chandrayaan-1.
CARTOSAT-1 CARTOSAT-1 carries two panchromatic cameras that take black-and-white stereoscopic pictures in the visible region of the electromagnetic spectrum. The imageries have a spatial resolution of 2.5 metre. The cameras cover a swath of 30 km and they are mounted in such a way that near simultaneous imaging of the same area from two different angles is possible. This facilitates in generating three-dimensional maps. The cameras are steerable across the direction of satellite’s movement to facilitate the imaging of an area more frequently.
CARTOSAT-1 carries two panchromatic cameras that take black-and-white stereoscopic pictures in the visible region of the electromagnetic spectrum. The imageries have a spatial resolution of 2.5 metre. The cameras cover a swath of 30 km and they are mounted in such a way that near simultaneous imaging of the same area from two different angles is possible. This facilitates in generating three-dimensional maps. The cameras are steerable across the direction of satellite’s movement to facilitate the imaging of an area more frequently. CARTOSAT-1 also carries a Solid State Recorder with a capacity of 120 Giga Bits to store the images taken by its cameras. These images can later be transmitted when the satellite comes within the visibility of a ground station. CARTOSAT-1
will give further fillip to remote sensing services by providing imagery
with improved spatial resolution. The unique high-resolution along-track
stereo imaging
HAMSAT HAMSAT is ISRO’s contribution to the international community of Amateur Radio Operators. This effort is also meant to bring ISRO’s satellite services within the reach of the common man and popularise space technology among the masses. This satellite will play a valuable role by providing a low cost readily accessible means of communication during emergencies and calamities like flood, earthquakes, etc. Besides, it will stimulate technical interest and awareness among the younger generation by providing them with an opportunity to develop their technological projects including offering a platform for testing new technologies. Some of the new technologies being incorporated in HAMSAT include Integrated Processor based Electronic Bus Management Unit, Lithium Ion Battery and Gallium Arsenide based solar panels.
With the switching on of the UHF/VHF (Mode-B) transponder on board HAMSAT on May 6, 2005, HAMs worldwide have witnessed hectic activities. HAMs have been sending their feedback on the performance of the satellite. E-mails have been received from HAMs in India, Canada, USA, Malaysia, Australia, Germany, Brazil, UK, Italy and Spain, confirming excellent quality of transmission by HAMSAT, both in terms of power and clarity. A few Hams have even sent actual audio recordings of conversation carried out via HAMSAT.
Second
Launch Pad (SLP) SLP was built by involving Indian industry on a turnkey basis including design and engineering, procurement of systems and sub-systems, fabrication, erection and commissioning of facilities including civil works.
SLP
consists of the following major elements:
Mobile Launch Pedestal (MLP): The 19.5 x 19.5 m MLP with bogie system is used to transfer the integrated vehicle from VAB to the launch pad located at a distance of 1 km. With a height 8.6 m, MLP weighs about 700 tonne and caters for both PSLV and GSLV requirements. It has a removable bogie system at the bottom, which has a hydraulic system. Umbilical Tower (UT): The 70 m tall, 10 x 10 m UT weighs about 980 tonne. The fully integrated vehicle on MLP, on its arrival on rail track, is interfaced with the UT with electrical, pneumatic and fluid filling lines. The final operations like fuel filling, gas charging and the vehicle checkout are carried out on UT. It has three platforms, which can be swung and also moved vertically to different levels. UT has an elevator and a 10 tonne tower crane at the top of the tower. It has a cryo arm for cryogenic fuel filling operations and monitoring till the last minute of launch operations. Jet Deflector: The jet deflector system is used to move the hot gases, ejected from the launcher during lift-off, away from the launch pad so as to reduce the thermal and acoustic loads on the vehicle. The design and construction of jet deflector was one of the major engineering challenges. It has diaphragm wall construction with piles driven 45 m below ground, constructed for the first time on the east coast of India. Lightning Protection Towers: In order to protect the launch vehicle from severe lightning when the vehicle is exposed for longer duration, lightning protection towers are erected around UT. There are four lightening protection towers of 120 m height around UT, which are interconnected through cables. Propellant
Storage and Servicing Facilities: Propellant storage and servicing
facilities cater to storage of about 1000 tonne of earth storable
propellants (UDMH and N2O4), cryogenic propellants (liquid Oxygen
and liquid Hydrogen), water, etc. Utilities: These include instrumentation and control systems, compressed air and fire fighting system, overhead tank, water treatment plant, electrical substation, air conditioning plant and safety systesm. Track for Movement of MLP: MLP with the integrated vehicle moves on a twin double rail track with a span of 14 m and a length of 1 km.
|
