''Lunokhod 1'' ( Russian: Луноход-1 "Moonwalker 1"), also known as Аппарат 8ЕЛ № 203 ("Device 8EL No. 203") was the first robotic rover on the Moon and the first to freely move across the surface of an

astronomical object An astronomical object, celestial object, stellar object or heavenly body is a naturally occurring physical entity, association, or structure that exists within the observable universe. In astronomy, the terms ''object'' and ''body'' are of ...

beyond the Earth. Sent by the

Soviet Union The Union of Soviet Socialist Republics. (USSR), commonly known as the Soviet Union, was a List of former transcontinental countries#Since 1700, transcontinental country that spanned much of Eurasia from 1922 until Dissolution of the Soviet ...

it was part of the robotic rovers Lunokhod program. The '' Luna 17''

spacecraft A spacecraft is a vehicle that is designed spaceflight, to fly and operate in outer space. Spacecraft are used for a variety of purposes, including Telecommunications, communications, Earth observation satellite, Earth observation, Weather s ...

carried ''Lunokhod 1'' to the Moon in 1970. Lunokhod 0 (No.201), the previous and first attempt to land a rover, launched in February 1969 but failed to reach Earth orbit. Although only designed for a lifetime of three lunar days (approximately three Earth months), ''Lunokhod 1'' operated on the lunar surface for eleven lunar days (321 Earth days) and traversed a total distance of 10.54 km.

Rover description

''Lunokhod 1'' was a lunar vehicle formed of a tub-like compartment with a large convex lid on eight independently powered wheels. The rover stood high and had a mass of . It was about long and wide. ''Lunokhod 1'' was equipped with a cone-shaped antenna, a highly directional

helical antenna A helical antenna is an antenna consisting of one or more conducting wires wound in the form of a helix. A helical antenna made of one helical wire, the most common type, is called ''monofilar'', while antennas with two or four wires in a h ...

, four

television camera A professional video camera (often called a television camera even though its use has spread beyond television) is a high-end device for creating electronic moving images (as opposed to a movie camera, that earlier recorded the images on filmstoc ...

s, and special extendable devices to test the

lunar soil Lunar regolith is the unconsolidated material found on the selenography, surface of the Moon and in the Lunar atmosphere, Moon's tenuous atmosphere. Sometimes referred to as Lunar soil, Lunar soil specifically refers to the component of regoli ...

for soil density and mechanical properties. An X-ray spectrometer, an

X-ray telescope An X-ray telescope (XRT) is a telescope that is designed to observe remote objects in the X-ray spectrum. X-rays are absorbed by the Earth's atmosphere, so instruments to detect X-rays must be taken to high altitude by balloons, sounding rockets ...

cosmic ray Cosmic rays or astroparticles are high-energy particles or clusters of particles (primarily represented by protons or atomic nuclei) that move through space at nearly the speed of light. They originate from the Sun, from outside of the ...

detectors, and a laser retro-reflector (supplied by France) were also included. The vehicle was powered by batteries which were recharged during the

lunar day A lunar day is the time it takes for Earth's Moon to complete on its axis one synodic rotation, meaning with respect to the Sun. Informally, a lunar day and a lunar night is each approximately 14 Earth days. The formal lunar day is therefore t ...

by a

solar cell A solar cell, also known as a photovoltaic cell (PV cell), is an electronic device that converts the energy of light directly into electricity by means of the photovoltaic effect.

array mounted on the underside of the lid. To be able to work in a vacuum, special fluoride-based lubricant was used for the mechanical parts, and the electric motors (one in each wheel hub) were enclosed in pressurized containers. During the lunar nights, the lid was closed, and a

polonium-210 Polonium-210 (210Po, Po-210, historically radium F) is an isotope of polonium. It undergoes alpha decay to stable 206Pb with a half-life of 138.376 days (about months), the longest half-life of all naturally occurring polonium isotopes (210– ...

radioisotope heater unit A radioisotope heater unit (RHU) is a small device that provides heat through radioactive decay. They are similar to tiny radioisotope thermoelectric generators (RTG) and normally provide about one watt of heat each, derived from the decay of ...

kept the internal components at

operating temperature An operating temperature is the allowable temperature range of the local ambient environment at which an electrical or mechanical device operates. The device will operate effectively within a specified temperature range which varies based on the de ...

. ''Lunokhod 1'' was intended to operate through three lunar days (approximately three Earth months), but actually operated for eleven lunar days.

Launch and lunar orbit

'' Luna 17'' was launched on November 10, 1970, at 14:44:01 UTC. After reaching earth

parking orbit A parking orbit is a temporary orbit used during the launch of a spacecraft. A launch vehicle follows a trajectory to the parking orbit, then coasts for a while, then engines fire again to enter the final desired trajectory. An alternative trajec ...

, the final stage of ''Luna 17''s launching rocket fired to place it into a trajectory towards the Moon (1970-11-10 at 14:54 UTC). After two course correction maneuvers (on November 12 and 14), it entered

lunar orbit In astronomy and spaceflight, a lunar orbit (also known as a selenocentric orbit) is an orbit by an object around Earth's Moon. In general these orbits are not circular. When farthest from the Moon (at apoapsis) a spacecraft is said to be at apo ...

on November 15, 1970, at 22:00 UTC.

Landing and surface operations

The spacecraft soft-landed on the Moon in the

Mare Imbrium Mare Imbrium (Latin ''imbrium'', the "Sea of Showers" or "Sea of Rains") is a vast lunar mare, lava plain within the Imbrium Basin on the Moon and is one of the larger craters in the Solar System. The Imbrium Basin formed from the collision ...

(''Sea of Rains'') on November 17 at 03:47 UTC. It landed in western Mare Imbrium, about 60 km south of the Promontorium Heraclides. The lander had dual ramps from which the payload, ''Lunokhod 1'', could descend to the lunar surface. At 06:28 UTC the rover moved onto the Moon's surface. The rover would run during the lunar day, stopping occasionally to recharge its batteries via the solar panels. At night the rover hibernated until the next sunrise, heated by the radioactive source. Small craters along its traverse were named unofficially during the mission. The names were officially approved by the IAU in 2012. They are called Albert,

Leonid Leonid ( ; ; ) is a Slavic version of the given name Leonidas. The French version is Leonide. People with the name include: * Leonid Agutin (born 1968), Russian pop musician and songwriter * Leonid Andreyev (1871–1919), Russian playwright ...

, Kolya, Valera, Borya, Gena, Vitya, Kostya, Igor, Slava, Nikolya, and Vasya. Operations during 1970: *November 17–22: The rover drove 197 m, returned 14 close-up pictures of the Moon and 12 panoramic views, during 10 communication sessions. It also conducted analyses of the lunar soil. *December 9–22: 1,522 m Operations during 1971: *January 8–20: 1,936 m *February 8–19: 1,573 m *March 9–20: 2,004 m *April 8–20: 1,029 m *May 7–20: 197 m *June 5–18: 1,559 m *July 4–17: 220 m *August 3–16: 215 m *August 31 – September 14: 88 m

Location

The final location of ''Lunokhod 1'' was uncertain until 2010, as

lunar laser ranging experiment Lunar Laser Ranging (LLR) is the practice of measuring Lunar distance (astronomy), the distance between the surfaces of the Earth and the Moon using Lidar, laser ranging. The distance can be calculated from the Round-trip delay, round-trip time ...

s had failed to detect a return signal from it since 1971. On March 17, 2010, Albert Abdrakhimov found both the lander and the rover in

Lunar Reconnaissance Orbiter The Lunar Reconnaissance Orbiter (LRO) is a NASA robotic spacecraft currently orbiting the Moon in an eccentric Polar orbit, polar mapping orbit. Data collected by LRO have been described as essential for planning NASA's future human and robotic ...

image M114185541RC (Line 21977, Sample 3189). In April 2010, the Apache Point Observatory Lunar Laser-ranging Operation (APOLLO) team from the University of California at San Diego used the LRO images to locate the rover closely enough for laser range (distance) measurements. On April 22, 2010, and days following, the team successfully measured the distance several times. The intersection of the spheres described by the measured distances then pinpoint the current location of Lunokhod 1 to within 1 meter. APOLLO is now using ''Lunokhod 1''s reflector for experiments, as they discovered, to their surprise, that it was returning much more light than other reflectors on the Moon. According to a NASA press release, APOLLO researcher Tom Murphy said, "We got about 2,000 photons from Lunokhod 1 on our first try. After almost 40 years of silence, this rover still has a lot to say." By November 2010, the location of the rover had been determined to within about a centimeter. The location near the limb of the Moon, combined with the ability to range the rover even when it is in sunlight, promises to be particularly useful for determining aspects of the Earth–Moon system. In a report released in May 2013, French scientists at the Côte d'Azur Observatory led by Jean-Marie Torre reported replicating the 2010 laser ranging experiments by American scientists after research using images from the

NASA The National Aeronautics and Space Administration (NASA ) is an independent agencies of the United States government, independent agency of the federal government of the United States, US federal government responsible for the United States ...

. In both cases, laser pulses were returned from the ''Lunokhod 1''

retroreflector A retroreflector (sometimes called a retroflector or cataphote) is a device or surface that reflects light or other radiation back to its source with minimum scattering. This works at a wide range of angle of incidence (optics), angle of incidenc ...

.Scientists Use Laser to Find Soviet Moon Rover
space-travel.com, May 2, 2013

End of mission and results

Controllers finished the last communications session with ''Lunokhod 1'' at 13:05 UT on September 14, 1971. Attempts to re-establish contact were finally discontinued and the operations of ''Lunokhod 1'' officially ceased on October 4, 1971, the anniversary of

Sputnik 1 Sputnik 1 (, , ''Satellite 1''), sometimes referred to as simply Sputnik, was the first artificial Earth satellite. It was launched into an elliptical low Earth orbit by the Soviet Union on 4 October 1957 as part of the Soviet space program ...

. During its 322 Earth days of operations, ''Lunokhod 1'' travelled 10,540 metres (6.55 miles) and returned more than 20,000 TV images and 206 high-resolution panoramas. In addition, it performed 25

analyses with its RIFMA

x-ray fluorescence X-ray fluorescence (XRF) is the emission of characteristic "secondary" (or fluorescent) X-rays from a material that has been excited by being bombarded with high-energy X-rays or gamma rays. The phenomenon is widely used for elemental analysis ...

spectrometer and used its penetrometer at 500 different locations.

Gallery

File:FP2A3576 (23497689198).jpg, Lunokhod 1 in the Museum of Cosmonautics (Moscow) File:Lunokhod moonrover.jpg, Top view of Lunokhod 1 model File:Lunokhod 1 - Control panel - Fragment A.jpg, Part of the Lunokhod 1 control panel. Museum of Space and Missile Technology (Saint Petersburg) File:Lunokhod 1 - Control panel - Fragment B.jpg, Part of the Lunokhod 1 control panel.

References

External links

Zarya – ''Lunokhod 1'' chronology

* ttps://nssdc.gsfc.nasa.gov/nmc/spacecraft/display.action?id=1970-095A NSSDC Master Catalog: Spacecraft: ''Luna 17''/''Lunokhod 1''
Other Soviet lunar missions

including ''Lunokhod 1''

Old Moon Rover Beams Surprising Laser Flashes to Eartharchived
* {{Orbital launches in 1970 1 1970 in the Soviet Union Missions to the Moon Lunar rovers LQ04 quadrangle 1970 robots Robots of the Soviet Union Eight-wheeled robots Solar-powered robots Attached spacecraft Spacecraft launched in 1970 1970 on the Moon Successful space missions