Luna 2 (Russian: Луна 2), originally named the Second Soviet Cosmic Rocket and nicknamed Lunik 2 in contemporaneous media, was the sixth of the Soviet Union's Luna programme spacecraft launched to the Moon, E-1 No.7. It was the first spacecraft to touch the surface of the Moon, and the first human-made object to make contact with another celestial body.

The spacecraft was launched on 12 September 1959 by the Luna 8K72 s/n I1-7B rocket. It followed a direct path to the Moon. In addition to the radio transmitters sending telemetry information back to Earth, the spacecraft released a sodium vapour cloud so the spacecraft's movement could be visually observed. On 13 September 1959, it impacted the Moon's surface east of Mare Imbrium near the craters Aristides, Archimedes, and Autolycus.

Prior to impact, two sphere-shaped pennants with USSR and the launch date engraved in Cyrillic were detonated, sending pentagonal shields in all directions. Luna 2 did not detect radiation or magnetic belts around the Moon.

Luna 1 and the three spacecraft of Luna programme before it were part of the Ye-1 series of spacecraft with a mass of 156 kilograms (344 lb). Luna missions that failed to successfully launch or achieve good results remained unnamed and were not publicly acknowledged. The first unnamed probe exploded on launch on 23 September 1958. Two more launches were unsuccessfully attempted on 11 October 1958 and 4 December 1958. Luna 1 was the fourth launch attempt and the first partial success of the program. It launched on 2 January 1959 and missed the Moon by 5,965 kilometres (3,706 mi).

One mission separated Luna 1 and Luna 2, a launch failure that occurred with an unnamed probe on 18 June 1959. Luna 2 would be the Soviet Union's sixth attempt to impact the Moon. It was the second of the Ye-1a series, modified to carry a heavier payload of 156 kilograms (344 lb) and had a combined mass of 390.2 kilograms (860 lb). Luna 2 was similar in design to Luna 1, a spherical space probe with protruding antennas and instrumentation. The instrumentation was also similar to Luna 1, which included a triaxial fluxgate magnetometer, a piezoelectric detector, a scintillation counter, ion traps and two gas-discharge counters, while the Luna 2 included six gas-discharge counters. There were no propulsion systems on Luna 2 itself.

Luna 2 carried five different types of instruments to conduct various tests while it was on its way to the Moon. The scintillation counters were used to measure any ionizing radiation and the Cherenkov radiation detectors to measure electromagnetic radiation caused by charged particles. The primary scientific purpose of the Geiger Counter carried on Luna 2 was to determine the electron spectrum of the Van Allen radiation belt. It consisted of three STS-5 gas-discharge counters mounted on the outside of an airtight container. The last instrument on Luna 2 was a three component fluxgate magnetometer. It was similar to that used on Luna 1 but its dynamic range was reduced by a factor of 4 to ±750 gammas (nT) so that the quantisation uncertainty was ±12 gammas. The probe's instrumentation was powered by silver-zinc and mercury-oxide batteries.

The spacecraft also carried Soviet pennants which were located on the probe and on the Luna 2 rocket. The two sphere-shaped pennants in the probe had surfaces covered by 72 pentagonal elements in a pattern similar to that later used by association footballs. In the centre was an explosive charge designed to shatter the sphere, sending the pentagonal shields in all directions. Each pentagonal element was made of titanium alloy; the centre regular pentagon had the State Emblem of the Soviet Union with the Cyrillic letters СССР ("USSR") engraved below and was surrounded by five non-regular pentagons which were each engraved with СССР СЕНТЯБРЬ 1959 ("USSR SEPTEMBER 1959"). The third pennant was similar engravings on aluminium strips which were embossed on the last stage of the Luna 2 rocket.

The scientists took extra, unspecified precautions in preventing biological contamination of the Moon.