Luna 4
Luna 4 — the first Soviet soft-landing probe to leave Earth orbit (launched 2 April 1963). Its astronavigation system failed on the way, so the course correction never happened; it missed the Moon by about 8,400 km on 5 April and was left in a huge, elongated Earth orbit, transmitting until at least 7 April. (Its orbit is shown representatively.)
Key facts
Mission & specifications
Mission
- Operator
- OKB-1 (USSR)
- Launched
- April 2, 1963
- Status
- Lost
Trajectory
- Distance from the Sun
- 0.996 AU
- Computed from the cached position
- Distance from Earth
- 1,461,182 km
- Computed from cached positions
- Distance from Venus
- 0.276 AU
- Computed from cached positions
Mission
Luna 4 opened the Soviet Union's second generation of Moon probes: the Ye-6, a spacecraft built to set a small camera capsule gently on the lunar surface. Two earlier Ye-6 launches had failed: one never reached orbit and the other never left it. Luna 4, launched on 2 April 1963, got away: an upper stage fired it from a parking orbit onto a curving path toward the Moon. Then its Yupiter astronavigation system failed, most likely because of thermal-control problems, and the spacecraft could not be pointed for its mid-course correction. Radio contact held, but Luna 4 missed the Moon by about 8,400 km on 5 April and was left in an enormous, elongated orbit around Earth, stretching from about 89,000 to 694,000 km. It kept transmitting until at least 7 April. Moscow announced only that it would travel "to the vicinity of the Moon", and a Radio Moscow programme called "Hitting the Moon", scheduled for the evening of 5 April, was cancelled. Its real purpose, a soft landing, was confirmed later. The Ye-6 would fail repeatedly — Luna 5, 6, 7 and 8 all fell short — before Luna 9 finally made the first soft landing on the Moon in February 1966.
- 1963Launch toward the MoonLaunch
A Molniya rocket puts the Ye-6 in a parking orbit, then sends it on a curving path to the Moon.
With its navigation system failed, it passes about 8,400 km from the Moon and is left in a huge Earth orbit.
- 1963Last reported signalMission end
Its transmitter is heard at least until 7 April.
Images
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