India puts four satellites in space in preparation for moon mission

Thursday, 11 January 2007, 18:30 IST
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Sriharikota (Andhra Pradesh): Indian space scientists Wednesday celebrated the "textbook" launch of four satellites from an indigenous launch vehicle for the first time, but said a moon mission was still at least eight years away. The Indian Space Research Organisation (ISRO)successfully sent into orbit four satellites with the help of the PSLV C7 (Polar Satellite Launch Vehicle). Exactly six months after the failure of the last launch attempt in July, two of the four satellites put into orbit were Indian-made ones and two were from Indonesia and Argentina. Describing the launch as "a textbook" one, ISRO chairperson Madhavan Nair said: "It is a great day for the country. We have done it and we have done it precisely." The take off time of the 295-tonne PSLV was 9.23 a.m. Within 19 minutes, the carrier attained a height of 639 km. Until now, Indian launch vehicles have only carried three satellites at a time into orbit. To accommodate four payloads, PSLV-C7 was fitted with a dual launch adopter, also for the first time in India. The 44-meter tall PSLV-C7 carried the Cartosat-2, a 550-kg space capsule recovery experiment (SRE-1), a 56-kg Indonesian satellite Lapan-Tubsat and a six-kg nano-satellite, Pehuensat-1, from Argentina. The Cartosat separated perfectly and took to its destined polar synchronised orbit at 17-plus minutes after takeoff and the nano-satellite reached its station in 17 minutes. The SRE-I - the most important satellite in this mission - went into orbit at 18 minutes and the Indonesian satellite went into orbit last, at about 19 minutes, 34 seconds after lift-off.As many as 844 different systems and processes (specified activities) had to be integrated before the lift-off. The PSLV mission is said to be path breaking as India is testing out a recoverable capsule for the first time, ahead of its first moon mission. Nair said the launch had "captured back the country's confidence in our space mission". It would take "at least eight years for a manned mission to the moon from India", Nair clarified. Denying any pressure on ISRO to prove itself after the July 10 failure of its GSLV (geo-satellite launch vehicle) mission, Nair said: "We planned this mission two years ago." Following the GSLV disaster, "we had to go through the entire quality control process", he said. "We have gone through a process of calibration checks, review of processes and subsystems. "The precision with which this mission went off... I challenge any country to perform such a perfect launch," the ISRO chief said. The re-entry and recovery phase is the most crucial part of any manned mission in outer space and the success of this experiment will be a signal from ISRO that India has started preparations for its journey to the moon. India has never before actually tested re-entry and recovery, and will gain first hand knowledge of the various temperature changes and their effect on spacecraft. ISRO will check out navigation, guidance and control technologies during the re-entry phase, scheduled two weeks from now. The SRE has an aero-thermal protection system and ISRO is testing basic technology for protective outer jackets for satellites and vehicles, mission director N. Narayana Moorthy told reporters. The SRE-1 also contains a spacecraft platform, a floating system, a parachute to control its drop, and micro-gravity payloads that will reduce its plunge speed. It will remain in a circular orbit for the first 10 days and is likely to be placed in an elliptical orbit on day 11. The SRE-1 can remain in this elliptical orbit for as long as scientists need it to stay in space. The SRE will be reoriented in this orbit and then its de-boost rocket will be fired to make it re-enter the earth's atmosphere any time in the next two weeks after day 11. Once it enters the earth's atmosphere, its parachute system opens and reduces its touchdown speed. The SRE-1 is scheduled to plunge into the Bay of Bengal, about 140 km east of Sriharikota island, from where it was launched, on day 13. The Indian Navy will recover the experimental capsule, in coordination with ISRO. The decision to test the re-entry and recovery technology was taken after 80 scientists from across the country gave their unanimous consent to sending a manned mission to space at a conference in Bangalore in November at the instance of Prime Minister Manmohan Singh. The PSLV-C7 has also carried to space India's second mapping satellite, the 680-kg Cartosat, which is the 12th remote sensing satellite the country is placing in orbit. It can provide scene-specific spot imagery. The satellite has a panchromatic camera to provide imagery with a spatial resolution of less than one meter and a swathe of 9.6 km. The data available from it will be used for planning rural and urban development, officials said. The satellite will also have high agility with the capability of steering across the track up to plus-45 degrees. The revisiting time of the satellite is four days and it will be active for five years. The Indonesian Lapan-Tubsat is an earth observation satellite while Argentina's Pehuensat-1 is intended to gain experience for designing more complex miniatures for educational, technological and scientific purposes. ISRO's last mission, the GSLV FO2 (geo-satellite launch vehicle), had failed on July 10. On the space capsule recovery experiment (SRE-1), the capsule that is scheduled to return to earth 13 days from now, Nair said: "Bringing back a spacecraft is a technological challenge. We don't know many things about re-entry." He said that in 2008, with the Chandrayan-I mission, ISRO would place around the moon "an instrumentation payload that will survey the surface of the moon. It will have X-ray and gamma-ray analyzers and a deep space tracking network". ISRO plans an INSAT 4B launch in March from Ariane's South American station. Later in the year a GSLV launch is also on the cards.
Source: IANS
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