Mars 1 was the first spacecraft to fly by Mars, although communications had been lost before it reached the planet. It was an automatic interplanetary station launched with the intent of flying by Mars at a distance of about 11,000 km. It was designed to image the surface and send back data on cosmic radiation, micrometeoroid impacts and Mars' magnetic field, radiation environment, atmospheric structure, and possible organic compounds. After leaving Earth orbit, the spacecraft and the booster fourth stage separated and the solar panels were deployed. Early telemetry indicated that there was a leak in one of the gas valves in the orientation system so the spacecraft was transferred to gyroscopic stabilization. Sixty-one radio transmissions were held, initially at two day intervals and later at 5 days in which a large amount of interplanetary data were collected. On 21 March 1963, when the spacecraft was at a distance of 106,760,000 km from Earth on its way to Mars communications ceased, probably due to failure of the spacecraft orientation system. Mars 1 closest approach to Mars occurred on 19 June 1963 at a distance of approximately 193,000 km, after which the spacecraft entered a heliocentric orbit. Spacecraft and Subsystems Mars 1 was a modified Venera-type spacecraft in the shape of a cylinder 3.3 m long and 1.1 m in diameter with a mass of 893.5 kg. The spacecraft measured 4 meters across with the solar panels and radiators deployed. The cylinder was divided into two compartments. The upper 2.7 m, the orbital module, contained guidance and on-board propulsion systems. The experiment module, containing the scientific instrumentation, comprised the bottom 0.6 m of the cylinder. A 1.7 m parabolic high gain antenna was used for communication, along with an omnidirectional antenna and a semi-directional antenna. Power was supplied by two solar panel wings with a total area of 2.6 square meters affixed to opposite sides of the spacecraft. Power was stored in a 42 amp-hour cadmium-nickel battery. Positional and orientation knowledge were achieved through Sun and star sensors. The interior of the station was sealed with a pressure of 1.1 atm. Communications were via three radio systems, at 1.6 m, 32 cm, and 5 and 8 cm wavelengths. The 32-cm wavelength radio transmitter mounted in the orbital module used the high-gain antenna. This was supplemented by the 1.6 m wavelength range transmitter through the two omnidirectional antennae extending from the solar panels. The 8 centimeter wavelength transmitter mounted in the experiment module was designed to transmit the TV images. Also mounted in the experiment module was a 5-centimeter range impulse transmitter. The station is designed to transmit automatically at 2-day intervals initially (until Dec. 13) and then at 5-day intervals, and can be commanded from the ground to transmit. Temperature was maintained between 20 C and 30 C using a binary gas-liquid system with heat exchangers and hemispherical radiators mounted on the ends of the solar panels. The craft carried various scientific instruments including a magnetometer probe, mounted on a boom extending from the orbital compartment, television photographic equipment, a spectroreflexometer, radiation sensors (gas-discharge and scintillation counters), a spectrograph to study ozone absorption bands, a radio telescope (150 and 1500 m wavelengths), and a micrometeoroid instrument. Scientific Results The probe recorded one micrometeorite strike every two minutes at altitudes ranging from 6000 to 40,000 km due to the Taurids meteor shower and also recorded similar densities at distances from 20 to 40 million km. Magnetic field intensities of 3-4 gammas with peaks as high as 6-9 gammas were measured in interplanetary space and the solar wind was detected. Measurements of cosmic rays showed that their intensity had almost doubled since 1959. The radiation zones around the Earth were detected and their magnitude confirmed. This spacecraft is also referenced as Sputnik 23 and Mars 2MV-4. It was originally designated Sputnik 30 in the U.S. Naval Space Command Satellite Situation Summary.