 The SRE-1 spacecraft on public display atThiruvananthapuram in April 2007 | |
| Mission type | Technology |
|---|---|
| Operator | ISRO |
| COSPAR ID | 2007-001C |
| SATCATno. | 29711 |
| Mission duration | 12 days |
| Spacecraft properties | |
| Manufacturer | ISRO |
| Launch mass | 555 kilograms (1,224 lb)[1] |
| Start of mission | |
| Launch date | 10 January 2007, 03:54 (2007-01-10UTC03:54Z) UTC |
| Rocket | PSLVPSLV C7 |
| Launch site | Satish DhawanFLP |
| Contractor | ISRO |
| End of mission | |
| Landing date | 22 January 2007, 04:16 (2007-01-22UTC04:17Z) UTC |
| Landing site | Bay of Bengal |
| Orbital parameters | |
| Reference system | Geocentric |
| Regime | Low Earth |
TheSpace Capsule Recovery Experiment (SCRE or more commonlySRE orSRE-1) is an Indian experimentalspacecraft which was launched at 03:53UTC on January 10, 2007, fromSriharikota by theIndian Space Research Organisation (ISRO). The launch was conducted using the C7 launch of thePSLV rocket, along with three other satellites. It remained in orbit for 12 days before re-entering the Earth's atmosphere and splashing down into theBay of Bengal at 04:16UTC on January 22.[2][3][4]
SRE-1 was designed to demonstrate the capability to recover an orbitingspace capsule, and the technology of an orbiting platform for performing experiments inmicrogravity conditions. It was also intended to test reusableThermal Protection System, navigation, guidance and control, hypersonic aero-thermodynamics, management of communication blackout, deceleration and flotation system and recovery operations.[5][6][7][8] The data obtained from the SRE mission was useful for the design and construction of theGaganyaan Crew Module.[9]
SRE-1 is a 555 kg capsule. It comprises aero-thermo structure, internal structure, Mission Management Unit, Altitude sensors and Inertial measurement unit, S-band transponder with unique belt array antenna embedded to ATS, power and electronics packages to support deceleration and flotation system. It also houses two microgravity 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. Theparachute,pyro devices,avionics packages of triggering unit and sequencer,telemetry and tracking system and sensors for measurement of system performance parameters are placed inside the SRE-1 capsule. Parachutes for SRE capsule were provided byAerial Delivery Research and Development Establishment (ADRDE).[10]
To withstand the heat of re-entry, thecone-shaped SRE-1 has athermal protection system composed of 264 silica tiles of 14 different types over conical surface,[11] and an ablative nose cap of carbon-phenolic composite. Scaled replica of SRE with this thermal protection system was validated in PlasmaWind Tunnel facility ofCIRA, Italy.[12] ISRO is also working on technology to manufacturecarbon-carbon composite TPS, which, along with the silica tiles tested with the SRE-1, could find use in future reusable spacecraft such as ISRO's plannedReusable Launch Vehicle.
SRE-1 was traveling around the Earth in a circular polar orbit at an altitude of 637 kilometers. In preparation for its reentry, SRE-1 was put into an elliptical orbit with aperigee of 485 kilometers and anapogee of 639 kilometers by issuing commands from the spacecraft control centre ofISTRAC atBangalore on January 19, 2007. The critical de-boost operations were executed from SCC,Bangalore supported by a network of ground stations at Bangalore,Lucknow,Sriharikota,Mauritius,Biak inIndonesia,Saskatoon in Canada,Svalbard in Norway besides shipborne and airborne terminals.
On January 22, 2007, the re-orientation of SRE-1 capsule for de-boost operations commenced at 08:42 amIST. The de-boost started at 09:00 am with the firing of on-board rocket motors and the operations were completed at 09:10 am. At 09:17 am, SRE-1 capsule was reoriented for its re-entry into the dense atmosphere. The capsule made its re-entry at 09:37 am at an altitude of 100 kilometers with a velocity of 8 km/s (ca. 29,000 km/h). During its reentry, the capsule was protected from the intense heat by carbon phenolicablative material and silica tiles on its outer surface.
By the time SRE-1 descended to an altitude of 5 km,aerodynamic braking had considerably reduced its velocity to 101 m/s (364 km/h). Pilot anddrogue parachute deployments helped in further reducing its velocity to 47 m/s (169 km/h).
The mainparachute was deployed at about 2 km altitude. SRE-1 splashed down in theBay of Bengal with a velocity of 12 m/s (43 km/h) at 09:46 am IST (04:16 amUTC). The flotation system, which was immediately triggered, kept the capsule afloat. Recovery operations were supported and carried out by theIndian Coast Guard andIndian Navy using ships, aircraft and helicopters.
Following recovery of all payloads, the SRE capsule has been put on display at theVSSC museum inTrivandrum.[13]
During its stay in orbit, the following two experiments on board SRE-1 were successfully conducted under microgravity conditions.
Performance of Silica TPS tiles in conical region of capsule was satisfactory and tile surfaces were found intact with some minor handling related damage during recovery operations. The spacecraft remained afloat for approximately two hours in seawater before recovery, causing minor cracks and seawater deposits on tile surfaces.[11]
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