This was the Soviet Union's first attempt to send a probe into interplanetary space and only the second spacecraft in history to be directed beyond Earth orbit.

  • The spacecraft was only slightly bigger than basketball-sized Sputnik.

  • The upper stage carried 2.2 pounds (1 kilogram) of sodium to create an artificial comet that could be photographed from Earth.

  • Shortly after launch, the rocket’s strap-on boosters began to vibrate and the rocket disintegrated at T+93 seconds, destroying its payload.

Nation Union of Soviet Socialist Republics (USSR) (1)
Objective(s) Lunar Impact
Spacecraft Ye-1 (No. 1)
Spacecraft Mass About 794 pounds (360 kilograms) (including the power sources installed on the upper stage)
Mission Design and Management Experimental Design Bureau-1 (OKB-1)
Launch Vehicle 8K72 (no. B1-3)
Launch Date and Time Sept. 23, 1958 / 07:03:23 UT
Launch Site Baikonur Cosmodrome / Site 1/5 (NIIP-5)
Scientific Instruments Ye-1:
1. Flux-Gate Magnetometer
2. Sodium-Iodide Scintillation Counter
3. Two Gas Discharge Geiger Counters
4. Two Micrometeorite Counters
5. Cherenkov Detector
6. Four Ion Traps

Blok Ye (upper stage):
1. Sodium Vapor Experiment
2. Scintillation Counter


  • This was the Soviet Union's first attempt to reach the Moon and to impact on its surface.

Key Dates

Launch: Sept. 23, 1958


The Soviet government approved a modest plan for initial exploration of the moon in March 1958. Engineers conceived of four initial probes, the Ye-1 (for lunar impact), Ye-2 (to photograph the far side of the moon), Ye-3 (to photograph the far side of the Moon), and Ye-4 (for lunar impact with a nuclear explosion).

The Ye-1 was a simple probe, a pressurized spherical object made from aluminum-magnesium alloy, approximately the size of the first Sputnik, that carried five scientific instruments. The goals of the mission were to study the gas component of interplanetary matter (using the proton traps), meteoric particles and photons in cosmic radiation (using the piezoelectric detectors), the magnetic fields of the moon and Earth (using the magnetometer), variations in cosmic ray intensity, and heavy nuclei in primary cosmic radiation. The probe (on its upper stage) also carried one kilogram of natrium to create an artificial comet on the outbound trajectory that could be photographed from Earth.

During the first Ye-1 launch, the booster developed longitudinal resonant vibrations on the strap-on boosters of the launch vehicle. The rocket eventually disintegrated at T+93 seconds destroying its payload.

The problem was traced to violent pressure oscillations in the combustion chamber of one of the strapon booster engines. This generated a resonant frequency vibration throughout the frame causing it to shake violently. A fix was proposed by reducing the thrust at T+85 seconds when the rocket reached maximum dynamic pressure.


Siddiqi, Asif A. Beyond Earth: A Chronicle of Deep Space Exploration, 1958-2016. NASA History Program Office, 2018.

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