- 04.02.63: Launch (08:04:00 UT)
- 04.05.63: Missed Lunar Impact, Entered Equatorial Earth Orbit (13:25:00 UT)
- 04.07.63: Lost Contact
- Status: Unknown
- Imaging System
- Radiation Detector
Luna 4 Information:
Unfortunately, during trans-lunar coast the Yupiter astronavigation system failed (most likely due to thermal control problems). This prevented the spacecraft from being properly oriented for the planned midcourse correction burn. The Soviets were able to maintain communications, but Luna 4 missed the Moon by about 8400 km and entered a 89 250 x 694 000 km equatorial Earth orbit. It transmitted at 183.6 MHz at least until 7 April.
Luna 4 was built by design bureau OKB-1 based on the Ye-6 satellite body. It had a mass of 1422 kg. While the Soviets never revealed the intended mission of the probe, it was announced it would travel to "the vicinity of the Moon". It was speculated the probe was designed to perform a soft landing on the Moon based on the trajectory and on the later attempted landings of the Luna 5 and 6 spacecraft, as well as the advances made over the 3 years since the successful Luna 3 flyby.