|
GSAT-3, also known as EDUSAT, was a communications satellite which was launched on 20 September 2004 by the Indian Space Research Organisation. EDUSAT is the first Indian satellite built exclusively to serve the educational sector. It is mainly intended to meet the demand for an interactive satellite-based distance education system for the country.〔(【引用サイトリンク】title=EDUSAT )〕 EDUSAT carries five Ku band transponders providing spot beams, one Ku band transponder providing a national beam and six extended C band transponders providing national coverage beams. EDUSAT was successfully launched into a Geosynchronous Transfer Orbit on the first operational launch of the Geosynchronous Satellite Launch Vehicle, which flew from the First Launch Pad at the Satish Dhawan Space Centre in Sriharikota. EDUSAT was initially placed into a transfer orbit with a perigee of and an apogee of and a period of 10.5 hours, inclined at 19.2 degrees to the equator. EDUSAT was decommissioned in September 2010 and relocated to a graveyard orbit.〔〔 ==Launch sequence== The 414 tonne, 49 m tall GSLV, carrying the 1950 kg GSAT-3, lifted off from Sriharikota at 4:01 pm. About seventeen minutes after lift off, the satellite was successfully placed in GTO. At 4.8 seconds before the countdown reached zero, the four liquid propellant strap-on stages, each carrying 40 tonne of hypergolic liquid propellants (UH25 and N2O4), were ignited. At count zero and after confirming the normal performance of all the four strap-on motors, the 138 tonne solid propellant first stage core motor was ignited and GSLV blazed into the sky. The major phases of the flight included the first stage burn-out at 104 seconds, the strap on burn-out at 150 seconds, ignition of the second stage at 150 seconds, heat shield separation at an altitude of 115 km and 227 seconds into the flight, second stage burn-out at 288 seconds, ignition of the 12.5 tonne cryogenic stage at 304 seconds and its shut down at 999 seconds after attaining the required velocity of 10.2 km per second. EDUSAT was put into orbit at 1014 seconds about 5000 km away from Sriharikota. The separated cryogenic stage was subsequently reoriented and passivated. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「GSAT-3」の詳細全文を読む スポンサード リンク
|