Luna 8 known as Lunik 8, was a lunar space probe of the Luna program. It was launched in on December 1965 with the objective of achieving a soft landing on the Moon; the mission did complete the experimental testing of its stellar-guidance system and the ground-control of its radio telemetry equipment, its flight trajectory, its other instrumentation. This, the eleventh Soviet attempt to achieve a lunar soft landing, nearly succeeded. After a successful midcourse correction on 4 December, this spacecraft headed toward the Moon without any apparent problems. Just before the scheduled firing of its retrorocket, a command was sent to inflate cushioning air bags around the landing probe. However, a plastic mounting bracket pierced one of the two air bags; the resulting ejection of the air put the spacecraft into a spin of about 12 degrees per second. The spacecraft momentarily regained its proper attitude, long enough for a nine-second-long retrorocket firing, but Luna 8 became unstable again. Without a retrorocket burn long enough to reduce its velocity sufficiently for a survivable landing, Luna 8 plummeted to the lunar surface and crashed at 21:51:30 UT on 6 December in the west of Oceanus Procellarum.
The coordinates of the crash site are 9.1°N 63.3°W / 9.1. Launch date/time: 3 December 1965 at 10:46:14 UTC On-orbit dry mass: 1,550 kg Zarya - Luna programme chronology
Cosmic rays are high-energy radiation originating outside the Solar System and from distant galaxies. Upon impact with the Earth's atmosphere, cosmic rays can produce showers of secondary particles that sometimes reach the surface. Composed of high-energy protons and atomic nuclei, they are originated either from the sun or from outside of our solar system. Data from the Fermi Space Telescope have been interpreted as evidence that a significant fraction of primary cosmic rays originate from the supernova explosions of stars. Active galactic nuclei appear to produce cosmic rays, based on observations of neutrinos and gamma rays from blazar TXS 0506+056 in 2018; the term ray is somewhat of a misnomer due to a historical accident, as cosmic rays were at first, wrongly, thought to be electromagnetic radiation. In common scientific usage, high-energy particles with intrinsic mass are known as "cosmic" rays, while photons, which are quanta of electromagnetic radiation are known by their common names, such as gamma rays or X-rays, depending on their photon energy.
In current usage, the term cosmic ray exclusively refers to massive particles – those that have rest mass – as opposed to photons, which have no rest mass, neutrinos, which have negligible rest mass. Massive particles have additional, mass-energy when they are moving, due to relativistic effects. Through this process, some particles acquire tremendously high mass-energies; these are higher than the photon energy of the highest-energy photons detected to date. The energy of the massless photon depends on frequency, not speed, as photons always travel at the same speed. At the higher end of the energy spectrum, relativistic kinetic energy is the main source of the mass-energy of cosmic rays; the highest-energy fermionic cosmic rays detected to date, such as the Oh-My-God particle, had an energy of about 3×1020 eV, while the highest-energy gamma rays to be observed, very-high-energy gamma rays, are photons with energies of up to 1014 eV, the highest energy neutrinos detected so far have energies of several 1015 eV.
Hence, the highest-energy detected fermionic cosmic rays are about 3×106 times as energetic as the highest-energy detected cosmic photons. Of primary cosmic rays, which originate outside of Earth's atmosphere, about 99% are the nuclei of well-known atoms, about 1% are solitary electrons. Of the nuclei, about 90% are simple protons; these fractions vary over the energy range of cosmic rays. A small fraction are stable particles of antimatter, such as positrons or antiprotons; the precise nature of this remaining fraction is an area of active research. An active search from Earth orbit for anti-alpha particles has failed to detect them. Cosmic rays attract great interest due to the damage they inflict on microelectronics and life outside the protection of an atmosphere and magnetic field, scientifically, because the energies of the most energetic ultra-high-energy cosmic rays have been observed to approach 3 × 1020 eV, about 40 million times the energy of particles accelerated by the Large Hadron Collider.
One can show that such enormous energies might be achieved by means of the centrifugal mechanism of acceleration in active galactic nuclei. At 50 J, the highest-energy ultra-high-energy cosmic rays have energies comparable to the kinetic energy of a 90-kilometre-per-hour baseball; as a result of these discoveries, there has been interest in investigating cosmic rays of greater energies. Most cosmic rays, however, do not have such extreme energies. After the discovery of radioactivity by Henri Becquerel in 1896, it was believed that atmospheric electricity, ionization of the air, was caused only by radiation from radioactive elements in the ground or the radioactive gases or isotopes of radon they produce. Measurements of increasing ionization rates at increasing heights above the ground during the decade from 1900 to 1910 could be explained as due to absorption of the ionizing radiation by the intervening air. In 1909, Theodor Wulf developed an electrometer, a device to measure the rate of ion production inside a hermetically sealed container, used it to show higher levels of radiation at the top of the Eiffel Tower than at its base.
However, his paper published in Physikalische Zeitschrift was not accepted. In 1911, Domenico Pacini observed simultaneous variations of the rate of ionization over a lake, over the sea, at a depth of 3 metres from the surface. Pacini concluded from the decrease of radioactivity underwater that a certain part of the ionization must be due to sources other than the radioactivity of the Earth. In 1912, Victor Hess carried three enhanced-accuracy Wulf electrometers to an altitude of 5,300 metres in a free balloon flight, he found the ionization rate increased fourfold over the rate at ground level. Hess ruled out the Sun as the radiation's source by making a balloon ascent during a near-total eclipse. With the moon blocking much of the Sun's visible radiation, Hess still measured rising radiation at rising altitudes, he concluded that "The results of the observations seem most to be explained by the assumption that radiation of high penetrating power enters from above into our atmosphere." In 1913–1914, Werner Kolhörster confirmed Victor Hess's earlier results by measuring the increased ionization enthalpy rate at an altitude of 9 km.
Hess received the Nobel Prize in Physics in 1936
Mare Imbrium is a vast 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 of a proto-planet during the Late Heavy Bombardment. Basaltic lava flooded the giant crater to form the flat volcanic plain seen today; the basin's age has been estimated using uranium–lead dating methods to 3938 ± 4 million years ago, the diameter of the impactor has been estimated to be 250 ± 25 km. The Moon's maria have fewer features than other areas of the Moon because molten lava pooled in the craters and formed a smooth surface. Mare Imbrium is not as flat as it was because events have altered its surface. Mare Imbrium may have been formed when a proto-planet from the asteroid belt collided with the moon 3.8 billion years ago. With a diameter of 1145 km, Mare Imbrium is second only to Oceanus Procellarum in size among the maria, it is the largest mare associated with an impact basin; the Imbrium Basin is surrounded by three concentric rings of mountains, uplifted by the colossal impact event that excavated it.
The outermost ring of mountains has a diameter of 1300 km and is divided into several different ranges. The ring mountains are not as well developed to the north and west, it appears they were not raised as high in these regions by the Imbrium impact; the middle ring of mountains forms the Montes Alpes and the mountainous regions near the craters Archimedes and Plato. The innermost ring, with a diameter of 600 km, has been buried under the mare's basalt leaving only low hills protruding through the mare plains and mare ridges forming a circular pattern; the outer ring of mountains rise 7 km above the surface of Mare Imbrium. The Mare material is thought to be about 5 km deep. Surrounding the Imbrium Basin is a region blanketed by ejecta from the impact, extending 800 km outward. Encircling the basin is a pattern of radial grooves called the "Imbrium Sculpture", which have been interpreted as furrows cut in the Moon's surface by large projectiles blasted out of the basin at low angles, causing them to skim across the lunar surface ploughing out these features.
The sculpture pattern was first identified by Grove Karl Gilbert in 1893. Furthermore, a Moon-wide pattern of faults which run both radial to and concentric to the Imbrium basin were thought to have been formed by the Imbrium impact. At the region of the Moon's surface opposite Imbrium Basin, there is a region of chaotic terrain, thought to have been formed when the seismic waves of the impact were focused there after travelling through the Moon's interior. Mare Imbrium is about 750 miles wide. A mass concentration, or gravitational high, was identified in the center of Mare Imbrium from Doppler tracking of the five Lunar Orbiter spacecraft in 1968; the Imbrium mascon is the largest on the moon. The mascon was confirmed and mapped at higher resolution with orbiters such as Lunar Prospector and GRAIL. Like most of the other maria on the Moon, Mare Imbrium was named by Giovanni Riccioli, whose 1651 nomenclature system has become standardized; the earliest known name for the mare may be "The Shrine of Hecate".
Ewen A. Whitaker argues that this refers to Mare Imbrium, "the largest regular-shaped dark area unbroken by bright patches" that can be seen with the naked eye. Around 1600, William Gilbert made a map of the Moon that names Mare Imbrium "Regio Magna Orientalis". Michael van Langren's 1645 map named it "Mare Austriacum". Mare Imbrium is visible to the naked eye from Earth. In the traditional'Man in the Moon' image seen on the Moon in Western folklore, Mare Imbrium forms the man's right eye. On 17 November 1970 at 03:47 Universal Time, the Soviet spacecraft Luna 17 made a soft landing in the mare, at latitude 38.28 N, longitude 35.00 W. Luna 17 carried Lunokhod 1, the first rover to be deployed on the Moon. Lunokhod 1, a remote-controlled rover, was deployed and undertook a mission lasting several months. In 1971, the crewed Apollo 15 mission landed in the southeastern region of Mare Imbrium, between Hadley Rille and the Apennine Mountains. Commander David Scott and Lunar Module Pilot James Irwin spent three days on the surface of the Moon, including 18½ hours outside the spacecraft on lunar extra-vehicular activity.
Command Module Pilot Alfred Worden remained in orbit and acquired hundreds of high-resolution photographs of Mare Imbrium as well as other types of scientific data. The crew on the surface explored the area using the first lunar rover and returned to Earth with 77 kilograms of lunar surface material. Samples were collected from Mons Hadley Delta, believed to be a fault block of pre-Imbrian lunar crust, including the "Genesis Rock." This was the only Apollo mission to visit a lunar rille, to observe outcrops of lunar bedrock visible in the rille wall. On 17 March 2013, an object hit the lunar surface in Mare Imbrium and exploded in a flash of apparent magnitude 4; the crater could be as wide as 20 meters. Thi
The Luna programme called Lunik or Lunnik by western media, was a series of robotic spacecraft missions sent to the Moon by the Soviet Union between 1959 and 1976. Fifteen were successful, each designed as either an orbiter or lander, accomplished many firsts in space exploration, they performed many experiments, studying the Moon's chemical composition, gravity and radiation. Twenty-four spacecraft were formally given the Luna designation; those that failed to reach orbit were not publicly acknowledged at the time, not assigned a Luna number. Those that failed in low Earth orbit were given Cosmos designations; the estimated cost of the Luna programme was about $4.5 billion. Luna 1 missed its intended impact with the Moon and became the first spacecraft to fall into orbit around the Sun. Luna 2 mission hit the Moon's surface, becoming the first man-made object to reach the Moon. Luna 3 rounded the Moon that year, returned the first photographs of its far side, which can never be seen from Earth.
Luna 9 became the first probe to achieve a soft landing on another planetary body. It returned five black and white stereoscopic circular panoramas, which were the first close-up shots of the Lunar surface. Luna 10 became the first artificial satellite of the Moon. Luna 17 and Luna 21 carried the Lunokhod vehicles. Another major achievement of the Luna programme, with Luna 16, Luna 20 and Luna 24, was the ability to collect samples of lunar soil and return them to Earth; the programme returned 0.326 kg of lunar samples. The Luna missions were the first space-exploration sample return missions to rely on advanced robotics. Luna 15 designed to return soil samples from the lunar surface, underwent its mission at the same time as the Apollo 11 mission. Neil Armstrong and Buzz Aldrin were on the lunar surface when Luna 15 began its descent, the spacecraft crashed into a mountain minutes later. While the programme was active, it was Soviet practice not to release any details of missions which had failed to achieve orbit.
This resulted in Western observers assigning their own designations to the missions, for example Luna E-1 No.1, the first failure of 1958 which NASA believed was associated with the Luna programme, was known as Luna 1958A. NASA identified a spacecraft which it referred to as Luna 1966A as having launched on 30 April 1966, a spacecraft referred to as Luna 1969B as having launched on 15 April 1969, a spacecraft referred to as Luna 1970B as having launched on 19 February 1970; when details of Soviet launches were disclosed, no launches of Luna spacecraft were found to have occurred on those dates. Luna Luna-Glob Soviet moonshot Soviet space program Lunar and Planetary Department Moscow University Luna Series Profile by NASA's Solar System Exploration Encyclopædia Britannica, Luna Space Probe Soviet Luna Chronology Soviet Lunar Images Exploring the Moon: Luna Missions
X-ray astronomy is an observational branch of astronomy which deals with the study of X-ray observation and detection from astronomical objects. X-radiation is absorbed by the Earth's atmosphere, so instruments to detect X-rays must be taken to high altitude by balloons, sounding rockets, satellites. X-ray astronomy is the space science related to a type of space telescope that can see farther than standard light-absorption telescopes, such as the Mauna Kea Observatories, via x-ray radiation. X-ray emission is expected from astronomical objects that contain hot gases at temperatures from about a million kelvin to hundreds of millions of kelvin. Moreover, the maintenance of the E-layer of ionized gas high in the Earth's Thermosphere suggested a strong extraterrestrial source of X-rays. Although theory predicted that the Sun and the stars would be prominent X-ray sources, there was no way to verify this because Earth's atmosphere blocks most extraterrestrial X-rays, it was not until ways of sending instrument packages to high altitude were developed that these X-ray sources could be studied.
The existence of solar X-rays was confirmed early in the rocket age by V-2s converted to sounding rocket purpose, the detection of extraterrestrial X-rays has been the primary or secondary mission of multiple satellites since 1958. The first cosmic X-ray source was discovered by a sounding rocket in 1962. Called Scorpius X-1, the X-ray emission of Scorpius X-1 is 10,000 times greater than its visual emission, whereas that of the Sun is about a million times less. In addition, the energy output in X-rays is 100,000 times greater than the total emission of the Sun in all wavelengths. Many thousands of X-ray sources have since been discovered. In addition, the space between galaxies in galaxy clusters is filled with a hot, but dilute gas at a temperature between 10 and 100 megakelvins; the total amount of hot gas is five to ten times the total mass in the visible galaxies. The first sounding rocket flights for X-ray research were accomplished at the White Sands Missile Range in New Mexico with a V-2 rocket on January 28, 1949.
A detector was placed in the nose cone section and the rocket was launched in a suborbital flight to an altitude just above the atmosphere. X-rays from the Sun were detected by the U. S. Naval Research Laboratory Blossom experiment on board. An Aerobee 150 rocket was launched on June 12, 1962 and it detected the first X-rays from other celestial sources, it is now known that such X-ray sources as Sco X-1 are compact stars, such as neutron stars or black holes. Material falling into a black hole may emit X-rays; the energy source for the X-ray emission is gravity. Infalling gas and dust is heated by the strong gravitational fields of these and other celestial objects. Based on discoveries in this new field of X-ray astronomy, starting with Scorpius X-1, Riccardo Giacconi received the Nobel Prize in Physics in 2002; the largest drawback to rocket flights is their short duration and their limited field of view. A rocket launched from the United States will not be able to see sources in the southern sky.
In astronomy, the interstellar medium is the gas and cosmic dust that pervade interstellar space: the matter that exists between the star systems within a galaxy. It fills interstellar space and blends smoothly into the surrounding intergalactic medium; the interstellar medium consists of an dilute mixture of ions, molecules, larger dust grains, cosmic rays, magnetic fields. The energy that occupies the same volume, in the form of electromagnetic radiation, is the interstellar radiation field. Of interest is the hot ionized medium consisting of a coronal cloud ejection from star surfaces at 106-107 K which emits X-rays; the ISM is full of structure on all spatial scales. Stars are born deep inside large complexes of molecular clouds a few parsecs in size. During their lives and deaths, stars interact physically with the ISM. Stellar winds from young clusters of stars and shock waves created by supernovae inject enormous amounts of energy into their surroundings, which leads to hypersonic turbulence.
The resultant structures are stellar wind superbubbles of hot gas. The Sun is traveling through the Local Interstellar Cloud, a denser region in the low-density Local Bubble. To measure the spectrum of the diffuse X-ray emission from the interstellar medium over the energy range 0.07 to 1 keV, NASA launched a Black Brant 9 from White Sands Missile Range, New Mexico on May 1, 2008. The Principal Investigator for the mission is Dr. Dan McCammon of the University of Wisconsin–Madison. Balloon flights can carry instruments to altitudes of up to 40 km above sea level, where they are above as much as 99.997% of the Earth's atmosphere. Unlike a rocket where data are collected during a brief few minutes, balloons are able to stay aloft for much longer; however at such altitudes, much of the X-ray spectrum is still absorbed. X-rays with energies less than 35 keV cannot reach balloons. On July 21, 1964, the Crab Nebula supernova remnant was discovered to be a hard X-ray source by a scintillation counter flown on a balloon launched from Palestine, United States.
This was the first balloon-based detection of X-rays from a discrete cosmic X-ray source. The high-energy focusing telescope is a balloon-borne experiment to
The Moon is an astronomical body that orbits planet Earth and is Earth's only permanent natural satellite. It is the fifth-largest natural satellite in the Solar System, the largest among planetary satellites relative to the size of the planet that it orbits; the Moon is after Jupiter's satellite Io the second-densest satellite in the Solar System among those whose densities are known. The Moon is thought to have formed not long after Earth; the most accepted explanation is that the Moon formed from the debris left over after a giant impact between Earth and a Mars-sized body called Theia. The Moon is in synchronous rotation with Earth, thus always shows the same side to Earth, the near side; the near side is marked by dark volcanic maria that fill the spaces between the bright ancient crustal highlands and the prominent impact craters. After the Sun, the Moon is the second-brightest visible celestial object in Earth's sky, its surface is dark, although compared to the night sky it appears bright, with a reflectance just higher than that of worn asphalt.
Its gravitational influence produces the ocean tides, body tides, the slight lengthening of the day. The Moon's average orbital distance is 1.28 light-seconds. This is about thirty times the diameter of Earth; the Moon's apparent size in the sky is the same as that of the Sun, since the star is about 400 times the lunar distance and diameter. Therefore, the Moon covers the Sun nearly during a total solar eclipse; this matching of apparent visual size will not continue in the far future because the Moon's distance from Earth is increasing. The Moon was first reached in September 1959 by an unmanned spacecraft; the United States' NASA Apollo program achieved the only manned lunar missions to date, beginning with the first manned orbital mission by Apollo 8 in 1968, six manned landings between 1969 and 1972, with the first being Apollo 11. These missions returned lunar rocks which have been used to develop a geological understanding of the Moon's origin, internal structure, the Moon's history. Since the Apollo 17 mission in 1972, the Moon has been visited only by unmanned spacecraft.
Both the Moon's natural prominence in the earthly sky and its regular cycle of phases as seen from Earth have provided cultural references and influences for human societies and cultures since time immemorial. Such cultural influences can be found in language, lunar calendar systems and mythology; the usual English proper name for Earth's natural satellite is "the Moon", which in nonscientific texts is not capitalized. The noun moon is derived from Old English mōna, which stems from Proto-Germanic *mēnô, which comes from Proto-Indo-European *mḗh₁n̥s "moon", "month", which comes from the Proto-Indo-European root *meh₁- "to measure", the month being the ancient unit of time measured by the Moon; the name "Luna" is used. In literature science fiction, "Luna" is used to distinguish it from other moons, while in poetry, the name has been used to denote personification of Earth's moon; the modern English adjective pertaining to the Moon is lunar, derived from the Latin word for the Moon, luna. The adjective selenic is so used to refer to the Moon that this meaning is not recorded in most major dictionaries.
It is derived from the Ancient Greek word for the Moon, σελήνη, from, however derived the prefix "seleno-", as in selenography, the study of the physical features of the Moon, as well as the element name selenium. Both the Greek goddess Selene and the Roman goddess Diana were alternatively called Cynthia; the names Luna and Selene are reflected in terminology for lunar orbits in words such as apolune and selenocentric. The name Diana comes from the Proto-Indo-European *diw-yo, "heavenly", which comes from the PIE root *dyeu- "to shine," which in many derivatives means "sky and god" and is the origin of Latin dies, "day"; the Moon formed 4.51 billion years ago, some 60 million years after the origin of the Solar System. Several forming mechanisms have been proposed, including the fission of the Moon from Earth's crust through centrifugal force, the gravitational capture of a pre-formed Moon, the co-formation of Earth and the Moon together in the primordial accretion disk; these hypotheses cannot account for the high angular momentum of the Earth–Moon system.
The prevailing hypothesis is that the Earth–Moon system formed after an impact of a Mars-sized body with the proto-Earth. The impact blasted material into Earth's orbit and the material accreted and formed the Moon; the Moon's far side has a crust, 30 mi thicker than that of the near side. This is thought to be; this hypothesis, although not perfect best explains the evidence. Eighteen months prior to an October 1984 conference on lunar origins, Bill Hartmann, Roger Phillips, Jeff Taylor challenged fellow lunar scientists: "You have eighteen months. Go back to your Apollo data, go back to your computer, do whatever you have to, but make up your mind. Don't come to our conference unless you have something to say about the Moon's birth." At the 1984 conference at Kona, the giant impact hypothesis emerged as the most consensual theory. Before the conference, there were parti
Luna 16 known as Lunnik 16, was an unmanned space mission, part of the Soviet Luna program. Luna 16 was the first robotic probe to land on the Moon and return a sample of lunar soil to Earth after five unsuccessful similar attempts; the sample was returned from Mare Fecunditatis. It represented the first lunar sample return mission by the Soviet Union and was the third lunar sample return mission overall, following the Apollo 11 and Apollo 12 missions; the spacecraft consisted of two attached stages, an ascent stage mounted on top of a descent stage. The descent stage was a cylindrical body with four protruding landing legs, fuel tanks, a landing radar, a dual descent-engine complex. A main descent engine was used to slow the craft until it reached a cutoff point, determined by the on-board computer based on altitude and velocity. After cutoff a bank of lower-thrust jets was used for the final landing; the descent stage acted as a launch pad for the ascent stage. The ascent stage was a smaller cylinder with a rounded top.
It carried. The spacecraft descent stage was equipped with a television camera and temperature monitors, telecommunications equipment, an extendable arm with a drilling rig for the collection of a lunar soil sample; the Luna 16 automated station was launched toward the Moon from a preliminary Earth orbit and after one mid-course correction on 13 September it entered a circular 111 km with 70° inclination lunar orbit on 17 September 1970. The lunar gravity was studied from this orbit. After two orbital adjustments were performed on 18 September and 19 September the perilune was decreased to 15.1 km, as well as the inclination altered in preparation for landing. At perilune at 05:12 UT on 20 September, the main braking engine was fired, initiating the descent to the lunar surface. Six minutes at 05:18 UT, the spacecraft safely soft-landed in its target area at 0°41' south latitude and 56°18' east longitude, in the northeast area of Mare Fecunditatis 100 kilometers west of Webb crater and 150 km north of Langrenus crater.
This was the first landing made in the lunar night side. The main descent engine cut off at an altitude of 20 m, the landing jets cut off at 2 m height at a velocity less than 2.4 m/s, followed by vertical free fall. The mass of the spacecraft at landing was 1,880 kilograms. Less than an hour after landing, at 06:03 UT, an automatic drill penetrated the lunar surface to collect a soil sample. After drilling for seven minutes, the drill reached a stop at 35 centimeters depth and withdrew its sample and lifted it in an arc to the top of the spacecraft, depositing the lunar material in a small spherical capsule mounted on the main spacecraft bus; the column of regolith in the drill tube was transferred to the soil sample container. After 26 hours and 25 minutes on the lunar surface, at 07:43 UT on 21 September, the spacecraft's upper stage lifted off from the Moon; the lower stage of Luna 16 remained on the lunar surface and continued transmission of lunar temperature and radiation data. Three days on 24 September, after a direct ascent traverse with no mid-course corrections, the capsule, with its 101 grams of lunar soil, reentered Earth's atmosphere at a velocity of 11 kilometers per second.
The capsule parachuted down 80 kilometers southeast of the town of Jezkazgan in Kazakhstan at 05:25 UT on 24 September 1970. Analysis of the dark basalt material indicated a close resemblance to soil recovered by the American Apollo 12 mission. According to the Bochum Observatory in Germany and good-quality television pictures were returned by the spacecraft. Luna 16 was a landmark success for the Soviets in their deep-space exploration program. Three tiny samples of the Luna 16 soil were sold at Sotheby's auction for $442,500 in 1993. A series of 10-kopeck stamps was issued in 1970 to commemorate the flight of Luna 16 lunar probe and depicted the main stages of the programme: soft landing on Moon, launch of the lunar soil sample return capsule, parachute assisted landing back on Earth. Timeline of artificial satellites and space probes Lunar Orbiter 4 image showing the landing site of Luna 16 in Mare Fecunditatis. Zarya - Luna 16 chronology NASA NSSDC Master Catalog