Sputnik 2 (Russian pronunciation: [ˈsputʲnʲɪk], Russian: Спутник-2, Satellite 2), or Prosteyshiy Sputnik 2 (PS-2, Russian: Простейший Спутник 2, Simplest Satellite 2) was the second spacecraft launched into Earth orbit, on 3 November 1957, and the first to carry a living animal, a Soviet space dog named Laika. Laika died on the fourth orbit due to overheating caused by an air conditioning malfunction. [2]

Launched by the U.S.S.R., Sputnik 2 was a 4-metre-high (13 ft) cone-shaped capsule with a base diameter of 2 metres (6.6 ft) that weighed around 500 kilograms (1,100 lb), though it was not designed to separate from the rocket core that brought it to orbit, bringing the total mass in orbit to 7.79 tonnes (17,200 lb).[3] It contained several compartments for radio transmitters, a telemetry system, a programming unit, a regeneration and temperature-control system for the cabin, and scientific instruments. A separate sealed cabin contained the dog Laika.

Engineering and biological data were transmitted using the Tral D telemetry system, transmitting data to Earth for a 15-minute period during each orbit. Two photometers were on board for measuring solar radiation (ultraviolet and x-ray emissions) and cosmic rays. A 100 line television camera provided images of Laika.[4] Sputnik 2 was launched into space only 32 days after its predecessor Sputnik 1. Due to the huge success of Sputnik 1, Nikita Khrushchev ordered Sergei Korolev back to work creating a Sputnik 2 that needed to be ready for space for the 40th anniversary of the Bolshevik revolution.[5]

The plan for Sputnik 1 and Sputnik 2 was initiated and presented by Korolev, and was approved in January 1957. At that time, it was not clear that the Soviets' main satellite plan (which would eventually become Sputnik 3) would be able to get to space because of the ongoing issues with the R-7 ICBM, which would be needed to launch a satellite of that size. "Korolev proposed substituting two 'simple satellites' for the IGY satellite".[5] The choice to launch these two instead of waiting for the more advanced Sputnik 3 to be finished was largely motivated by the desire to launch a satellite to orbit before the US. (Wikipedia)