The Space Capsule Recovery Experiment (SCRE or more commonly SRE or SRE-1) is an Indian experimental

spacecraft A spacecraft is a vehicle that is designed spaceflight, to fly and operate in outer space. Spacecraft are used for a variety of purposes, including Telecommunications, communications, Earth observation satellite, Earth observation, Weather s ...

which was launched at 03:53

UTC Coordinated Universal Time (UTC) is the primary time standard globally used to regulate clocks and time. It establishes a reference for the current time, forming the basis for civil time and time zones. UTC facilitates international communica ...

on January 10, 2007, from

Sriharikota Sriharikota () is a barrier island off the Bay of Bengal coast located in the Shar Project settlement of Tirupati district in Andhra Pradesh, India. It houses the Satish Dhawan Space Centre, one of the two satellite launch centres in India (the ...

by the

Indian Space Research Organisation The Indian Space Research Organisation (ISRO ) is India's national List of government space agencies, space agency, headquartered in Bengaluru, Karnataka. It serves as the principal research and development arm of the Department of Space (DoS), ...

(ISRO). The launch was conducted using the C7 launch of the

PSLV The Polar Satellite Launch Vehicle (PSLV) is an expendable medium-lift launch vehicle designed and operated by the Indian Space Research Organisation (ISRO). It was developed to allow India to launch its Indian Remote Sensing (IRS) satellite ...

rocket, along with three other satellites. It remained in orbit for 12 days before re-entering the Earth's atmosphere and splashing down into the

Bay of Bengal The Bay of Bengal is the northeastern part of the Indian Ocean. Geographically it is positioned between the Indian subcontinent and the Mainland Southeast Asia, Indochinese peninsula, located below the Bengal region. Many South Asian and Southe ...

at 04:16

on January 22.

Overview

SRE-1 was designed to demonstrate the capability to recover an orbiting space capsule, and the technology of an orbiting platform for performing experiments in

microgravity Weightlessness is the complete or near-complete absence of the sensation of weight, i.e., zero apparent weight. It is also termed zero g-force, or zero-g (named after the g-force) or, incorrectly, zero gravity. Weight is a measurement of the fo ...

conditions. It was also intended to test reusable

Thermal Protection System Atmospheric entry (sometimes listed as Vimpact or Ventry) is the movement of an object from outer space into and through the gases of an atmosphere of a planet, dwarf planet, or natural satellite. Atmospheric entry may be ''uncontrolled entr ...

, navigation, guidance and control, hypersonic aero-thermodynamics, management of communication blackout, deceleration and flotation system and recovery operations. The data obtained from the SRE mission was useful for the design and construction of the Gaganyaan Crew Module.

Design

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. The

parachute A parachute is a device designed to slow an object's descent through an atmosphere by creating Drag (physics), drag or aerodynamic Lift (force), lift. It is primarily used to safely support people exiting aircraft at height, but also serves va ...

, pyro devices,

avionics Avionics (a portmanteau of ''aviation'' and ''electronics'') are the Electronics, electronic systems used on aircraft. Avionic systems include communications, Air navigation, navigation, the display and management of multiple systems, and the ...

packages of triggering unit and sequencer,

telemetry Telemetry is the in situ collection of measurements or other data at remote points and their automatic transmission to receiving equipment (telecommunication) for monitoring. The word is derived from the Greek roots ''tele'', 'far off', an ...

and tracking system and sensors for measurement of system performance parameters are placed inside the SRE-1 capsule. Parachutes for SRE capsule were provided by

Aerial Delivery Research and Development Establishment Aerial may refer to: Music * ''Aerial'' (album), by Kate Bush, and that album's title track * "Aerials" (song), from the album ''Toxicity'' by System of a Down Bands * Aerial (Canadian band) * Aerial (Scottish band) * Aerial (Swedish band) ...

(ADRDE). To withstand the heat of re-entry, the cone-shaped SRE-1 has a

thermal protection system Atmospheric entry (sometimes listed as Vimpact or Ventry) is the movement of an object from outer space into and through the gases of an atmosphere of a planet, dwarf planet, or natural satellite. Atmospheric entry may be ''uncontrolled entr ...

composed of 264 silica tiles of 14 different types over conical surface, and an ablative nose cap of carbon-phenolic composite. Scaled replica of SRE with this thermal protection system was validated in Plasma

Wind Tunnel A wind tunnel is "an apparatus for producing a controlled stream of air for conducting aerodynamic experiments". The experiment is conducted in the test section of the wind tunnel and a complete tunnel configuration includes air ducting to and f ...

facility of CIRA, Italy. ISRO is also working on technology to manufacture carbon-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 planned

Reusable Launch Vehicle A reusable launch vehicle has parts that can be recovered and reflown, while carrying payloads from the surface to outer space. Rocket stages are the most common launch vehicle parts aimed for reuse. Smaller parts such as fairings, booster ...

Re-entry

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 a

perigee An apsis (; ) is the farthest or nearest point in the orbit of a planetary body about its primary body. The line of apsides (also called apse line, or major axis of the orbit) is the line connecting the two extreme values. Apsides perta ...

of 485 kilometers and an

apogee An apsis (; ) is the farthest or nearest point in the orbit of a planetary body about its primary body. The line of apsides (also called apse line, or major axis of the orbit) is the line connecting the two extreme values. Apsides perta ...

of 639 kilometers by issuing commands from the spacecraft control centre of ISTRAC at

Bangalore Bengaluru, also known as Bangalore (List of renamed places in India#Karnataka, its official name until 1 November 2014), is the Capital city, capital and largest city of the southern States and union territories of India, Indian state of Kar ...

on January 19, 2007. The critical de-boost operations were executed from SCC,

supported by a network of ground stations at Bangalore,

Lucknow Lucknow () is the List of state and union territory capitals in India, capital and the largest city of the List of state and union territory capitals in India, Indian state of Uttar Pradesh and it is the administrative headquarters of the epon ...

Mauritius Mauritius, officially the Republic of Mauritius, is an island country in the Indian Ocean, about off the southeastern coast of East Africa, east of Madagascar. It includes the main island (also called Mauritius), as well as Rodrigues, Ag ...

Biak Biak is the main island of Biak Archipelago located in Cenderawasih Bay near the northern coast of Papua (province), Papua, an Indonesian province, and is just northwest of New Guinea. Biak has many atolls, reefs, and corals. The largest popula ...

Indonesia Indonesia, officially the Republic of Indonesia, is a country in Southeast Asia and Oceania, between the Indian Ocean, Indian and Pacific Ocean, Pacific oceans. Comprising over List of islands of Indonesia, 17,000 islands, including Sumatra, ...

Saskatoon Saskatoon () is the largest city in the Provinces and territories of Canada, Canadian province of Saskatchewan. It straddles a bend in the South Saskatchewan River in the central region of the province. It is located along the Trans-Canada Hig ...

in Canada,

Svalbard Svalbard ( , ), previously known as Spitsbergen or Spitzbergen, is a Norway, Norwegian archipelago that lies at the convergence of the Arctic Ocean with the Atlantic Ocean. North of continental Europe, mainland Europe, it lies about midway be ...

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 am IST. 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 phenolic ablative 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 and

drogue parachute A drogue parachute, also called drag chute, is a parachute designed for deployment from a rapidly moving object. It can be used for various purposes, such as to decrease speed, to provide control and stability, as a pilot parachute to deploy ...

deployments helped in further reducing its velocity to 47 m/s (169 km/h).

Splashdown and recovery

The main

was deployed at about 2 km altitude. SRE-1 splashed down in the

with a velocity of 12 m/s (43 km/h) at 09:46 am IST (04:16 am

). The flotation system, which was immediately triggered, kept the capsule afloat. Recovery operations were supported and carried out by the

Indian Coast Guard The Indian Coast Guard (ICG) is a maritime law enforcement and search and rescue agency of India with jurisdiction over its territorial waters including its contiguous zone and Exclusive economic zone of India, exclusive economic zone. It was st ...

and

Indian Navy The Indian Navy (IN) (ISO 15919, ISO: ) is the Navy, maritime and Amphibious warfare, amphibious branch of the Indian Armed Forces. The President of India is the Supreme Commander of the Indian Navy. The Chief of the Naval Staff (India), Chief ...

using ships, aircraft and helicopters.

Disposition

Following recovery of all payloads, the SRE capsule has been put on display at the VSSC museum in

Trivandrum Thiruvananthapuram ( ), also known as Trivandrum, is the capital city of the Indian state of Kerala. As of 2011, the Thiruvananthapuram Municipal Corporation had a population of 957,730 over an area of 214.86 sq. km, making it the largest and ...

Experiments and results

During its stay in orbit, the following two experiments on board SRE-1 were successfully conducted under microgravity conditions. *One of the experiments studied metal melting and crystallisation under microgravity conditions. This experiment, jointly designed by the

Indian Institute of Science The Indian Institute of Science (IISc) is a Public university, public, Deemed university, deemed, research university for higher education and research in science, engineering, design, and management. It is located in Bengaluru, Karnataka. The ...

and

Vikram Sarabhai Space Centre The Vikram Sarabhai Space Centre (VSSC) is a major space research centre of the Indian Space Research Organisation (ISRO), focusing on rocket and space vehicles for India's satellite programme. It is located in Thiruvananthapuram, in the India ...

Thiruvananthapuram Thiruvananthapuram ( ), also known as Trivandrum, is the Capital city, capital city of the Indian state of Kerala. As of 2011, the Thiruvananthapuram Municipal Corporation had a population of 957,730 over an area of 214.86 sq. km, making it the ...

, was performed in an isothermal heating furnace. *The second experiment, jointly designed by National Metallurgical Laboratory,

Jamshedpur Jamshedpur (; ), also known as Tatanagar, is a major industrial city in eastern India. It is the List of cities in Jharkhand by population, largest city in the state of Jharkhand. With a population of 629,658 in the city limits and 1.3 million ...

and ISRO Satellite Centre

, studied the synthesis of nano-crystals under microgravity conditions. This was an experiment in designing biomaterials that better replicate natural biological products. The experimental results have yet to be analysed. 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.

References

ISRO Presentation on Day 1 of the 14th annual meeting of the Asia Pacific Regional Space Agency Forum
{{Orbital launches in 2007 Satellites of India 2007 in India Spacecraft launched in 2007 Spacecraft which reentered in 2007 Test spaceflights Spacecraft launched by PSLV rockets