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Most people know one fact about Rakesh Sharma: in 1984 he became the first Indian in space. Fewer know what he did up there. His week in orbit was packed with experiments on the human body, on metals and on mapping India from above. This post goes through that science using the mission report, and works out the orbit he lived in with the gravitation formulas from Class 11.
Who is Rakesh Sharma?
His spacefacts.de cosmonaut record gives his birth as 13 January 1949 in Patiala and his selection as a cosmonaut candidate on 20 September 1982. He was an Indian Air Force pilot and test pilot. Later he was chief test pilot at Hindustan Aeronautics Limited, first at Nashik and then in Bangalore, until he stopped test flying in 2001.
A NASA translation of the Soviet mission report, The Space Flight of the Soviet-Indian Crew (NASA TM-77615, 1985), says two Indian candidates, R. Sharma and R. Malhotra, arrived at the Yuri Gagarin Cosmonaut Training Centre in September 1982. Sharma joined the main crew with commander Yuri Malyshev; Gennady Strekalov replaced the original flight engineer, who fell ill. Malhotra trained on the back-up crew.
When did the flight happen?
Soyuz T-11 lifted off from Baikonur on 3 April 1984, according to the spacefacts record, which gives the mission as 3 to 11 April and its length as 7 days 21 hours 40 minutes. The NASA report says the ship docked with the Salyut-7 station on 4 April, joining the crew already aboard, so six cosmonauts worked together. The three came home in the Soyuz T-10 capsule on 11 April, landing 46 km east of Arkalyk.
The government's gallantry awards portal lists Squadron Leader Rakesh Sharma as a recipient of the Ashoka Chakra, with an award date of 19 May 1984.
What experiments did he do?
The NASA report says the flight plan had eight experiments, six of them medical, plus one on materials and one on remote sensing. Some were repeated many times, so 43 experiment runs were done in all.
Optokinez. How the eyes and the balance organs of the inner ear work together without gravity.
Anketa and Opros. Questionnaires on motion sickness and mood at each stage of flight.
Vektor. The heart's electrical activity and blood flow, using electrocardiograph and kinetocardiograph methods.
Ballisto. Ballistocardiography, which detects tiny movements of the body caused by each heartbeat.
Yoga. Done by Sharma himself, testing whether yoga exercises could protect the muscles and support system from the effects of weightlessness. The report calls it "the most curious of the medical experiments."
Pereokhlazhdeniye (Supercooling). Melts of a silver-germanium alloy, chosen by Indian specialists, were studied in three compositions to see how far a liquid metal can be cooled below its freezing point and whether metallic glasses can form.
Terra. Photographs of India with the MKF-6M multizonal camera and the KATE-140 camera, plus hand-held cameras, matched with aircraft surveys and ground measurements by Indian teams. It was planned for nine passes over India; at Indian request two more passes were added to photograph Indian islands in the Bay of Bengal.
Worked example: how fast was Salyut-7 going?
The report gives the station's orbit as 294 km at its lowest and 305 km at its highest, with a period of 90 minutes. Let us check that with the satellite formulas in the NCERT Class 11 Gravitation chapter.
Orbit radius. Use the average height, (294 + 305) / 2 = 299.5 km. Add Earth's radius, 6,378 km: r = 6,677.5 km = 6.68 x 10^6 m.
Period. T = 2π √(r³ / GM), with GM for Earth = 3.986 x 10^14 m³/s². This gives T = 5,430 s, or 90.5 minutes. The report's 90 minutes checks out.
Speed. v = 2πr / T = 2π x 6,677.5 km / 5,430 s = 7.73 km/s, about 27,800 km/h.
Orbits in the mission. 7 days 21 hours 40 minutes is 189.7 hours, or 11,380 minutes. At about 90 minutes per orbit that is roughly 126 trips around the Earth.
Common mistakes:
Using the height instead of the radius. r is measured from Earth's centre, so always add Earth's radius.
Mixing km and m. GM is in m³/s², so r must be in metres before you cube it.
Our post on satellite problems in gravitation has more practice of this kind. If cubing and square-rooting large powers of ten keeps tripping you up, the Fermi Problem Library has worked problems with a step-by-step solver that explains the reasoning rather than printing an answer.
Why did the Terra survey matter to India?
The NASA report describes it as being of "great significance for India's national economy," because the photographs fed studies of India's natural resources. It also places the flight at the end of a long line of Indo-Soviet space work, including the launch of Aryabhata in 1975 and the Bhaskara satellites in 1979 and 1981 on Soviet rockets. Our post on Vikram Sarabhai covers how India's space programme began.
What can a student take from Sharma's mission?
A famous moment is also a work shift. The flight is remembered as a first, but most of its eight days went to careful, repeated measurement.
Bring your own question. The alloy and the yoga experiments were chosen with India in mind, so the flight answered questions Indian scientists cared about.
Fieldwork needs ground truth. Terra paired photographs from orbit with measurements on the ground, so the pictures could be trusted.
Try it now: redo the worked example for Soyuz T-11's first orbit, 202 km by 240 km, and compare your period with the 88.6 minutes in the report.
