Mission type | Lunar orbiter | ||||||||||||||||
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Operator | NASA | ||||||||||||||||
COSPAR ID | 2009-031A | ||||||||||||||||
SATCAT no. | 35315 | ||||||||||||||||
Website | lunar | ||||||||||||||||
Mission duration | |||||||||||||||||
Spacecraft properties | |||||||||||||||||
Manufacturer | NASA / GSFC | ||||||||||||||||
Launch mass | 1,916 kg (4,224 lb) [3] | ||||||||||||||||
Dry mass | 1,018 kg (2,244 lb) [3] | ||||||||||||||||
Payload mass | 92.6 kg (204 lb) [3] | ||||||||||||||||
Dimensions | Launch: 390 × 270 × 260 cm (152 × 108 × 103 in) [3] | ||||||||||||||||
Power | 1850 W [4] | ||||||||||||||||
Start of mission | |||||||||||||||||
Launch date | June 18, 2009, 21:32:00 UTC | ||||||||||||||||
Rocket | Atlas V 401 | ||||||||||||||||
Launch site | Cape Canaveral SLC-41 | ||||||||||||||||
Contractor | United Launch Alliance | ||||||||||||||||
Entered service | September 15, 2009 | ||||||||||||||||
Orbital parameters | |||||||||||||||||
Reference system | Selenocentric | ||||||||||||||||
Semi-major axis | 1,825 km (1,134 mi) | ||||||||||||||||
Periselene altitude | 20 km (12 mi) | ||||||||||||||||
Aposelene altitude | 165 km (103 mi) | ||||||||||||||||
Epoch | May 4, 2015 [5] | ||||||||||||||||
Moon orbiter | |||||||||||||||||
Orbital insertion | June 23, 2009 | ||||||||||||||||
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The Lunar Reconnaissance Orbiter (LRO) is a NASA robotic spacecraft currently orbiting the Moon in an eccentric polar mapping orbit. [6] [7] Data collected by LRO have been described as essential for planning NASA's future human and robotic missions to the Moon. [8] Its detailed mapping program is identifying safe landing sites, locating potential resources on the Moon, characterizing the radiation environment, and demonstrating new technologies. [9] [10]
Launched on June 18, 2009, [11] in conjunction with the Lunar Crater Observation and Sensing Satellite (LCROSS), as the vanguard of NASA's Lunar Precursor Robotic Program, [12] LRO was the first United States mission to the Moon in over ten years. [13] LRO and LCROSS were launched as part of the United States's Vision for Space Exploration program.
The probe has made a 3-D map of the Moon's surface at 100-meter resolution and 98.2% coverage (excluding polar areas in deep shadow), [14] including 0.5-meter resolution images of Apollo landing sites. [15] [16] The first images from LRO were published on July 2, 2009, showing a region in the lunar highlands south of Mare Nubium (Sea of Clouds). [17]
The total cost of the mission is reported as US$583 million, of which $504 million pertains to the main LRO probe and $79 million to the LCROSS satellite. [18] LRO has enough fuel to continue operations until at least 2026. [19]
Developed at NASA's Goddard Space Flight Center, LRO is a large (1,916 kg/4,224 lb [18] ) and sophisticated spacecraft. Its mission duration was planned for one year, [20] but has since been extended numerous times after review by NASA.
After completing a preliminary design review in February 2006 and a critical design review in November 2006, [21] the LRO was shipped from Goddard to Cape Canaveral Air Force Station on February 11, 2009. [22] Launch was planned for October 2008, but this slid to April as the spacecraft underwent testing in a thermal vacuum chamber. [23] Launch was rescheduled for June 17, 2009, because of the delay in a priority military launch, [24] and happened one day later, on June 18. The one-day delay was to allow the Space Shuttle Endeavour a chance to lift off for mission STS-127 following a hydrogen fuel leak that canceled an earlier planned launch. [25]
Areas of investigation include selenodetic global topography; the lunar polar regions, including possible water ice deposits and the lighting environment; characterization of deep space radiation in lunar orbit; and high-resolution mapping, at a maximum resolution of 50 cm/pixel (20 in/pixel), to assist in the selection and characterization of future landing sites. [26] [27]
In addition, LRO has provided images and precise locations of landers and equipment from previous and current lunar missions, including the Apollo sites. [15] In 2024, it confirmed the highly accurate landing site of the first successful Japanese SLIM soft landing. [28]
The orbiter carries a complement of six instruments and one technology demonstration:
Prior to the LRO's launch, NASA gave members of the public the opportunity to have their names placed in a microchip on the LRO. The deadline for this opportunity was July 31, 2008. [40] About 1.6 million names were submitted. [40] [41]
On June 23, 2009, the Lunar Reconnaissance Orbiter entered into orbit around the Moon after a four-and-a-half-day journey from the Earth. When launched, the spacecraft was aimed at a point ahead of the Moon's position. A mid-course correction was required during the trip in order for the spacecraft to correctly enter Lunar orbit. Once the spacecraft reached the far side of the Moon, its rocket motor was fired in order for it to be captured by the Moon's gravity into an elliptical lunar orbit. [42]
A series of four rocket burns over the next four days put the satellite into its commissioning phase orbit where each instrument was brought online and tested. On September 15, 2009, the spacecraft started its primary mission by orbiting the Moon at about 50 km (31 mi) for one year. [43] After completing its one-year exploration phase, in September 2010, LRO was handed over to NASA's Science Mission Directorate to continue the science phase of the mission. [44] It would continue in its 50 km circular orbit, but eventually would be transitioned into a fuel-conserving "quasi-frozen" [45] elliptical orbit for the remainder of the mission.
NASA's LCROSS mission culminated with two lunar impacts at 11:31 and 11:36 UTC on October 9. The goal of the impact was the search for water in the Cabeus crater near the Moon's south pole, [46] and preliminary results indicated the presence of both water and hydroxyl, an ion related to water. [47] [48]
On January 4, 2011, the Mini-RF instrument team for the Lunar Reconnaissance Orbiter (LRO) found that the Mini-RF radar transmitter had suffered an anomaly. Mini-RF has suspended normal operations. Despite being unable to transmit, the instrument is being used to collect bistatic radar observations using radar transmissions from the Earth. The Mini-RF instrument has already met its science mission success criteria by collecting more than 400 strips of radar data since September 2010. [49]
In January 2013, NASA tested one-way laser communication with LRO by sending an image of the Mona Lisa to the Lunar Orbiter Laser Altimeter (LOLA) instrument on LRO from the Next Generation Satellite Laser Ranging (NGSLR) station at NASA's Goddard Space Flight Center in Greenbelt, Maryland. [50]
In May 2015, LRO's orbit was altered to fly 20 km (12 mi) above the Moon's south pole, allowing higher resolution data to be obtained from the Lunar Orbiter Laser Altimeter (LOLA) and Diviner instruments over the permanently shadowed craters there. [51]
In 2019, LRO found the crash site of Indian moon lander Vikram. [52]
In 2020, software was tested to use star trackers instead of the Miniature Inertial Measurement Unit that had been turned off in 2018 (as it was degrading). [53]
LRO and the Chandrayaan-2 orbiter were expected to come dangerously close to each other on 20 October 2021 at 05:45 UTC over the Lunar North pole. Chandrayaan-2 orbiter performed a collision avoidance manoeuvre at 14:52 UTC on 18 October 2021 to avert the possible conjunction event. [54]
On August 21, 2009, the spacecraft, along with the Chandrayaan-1 orbiter, attempted to perform a bistatic radar experiment to detect the presence of water ice on the lunar surface, [55] [56] but the test was unsuccessful. [57]
On December 17, 2010, a topographic map of the Moon based on data gathered by the LOLA instrument was released to the public. [58] This is the most accurate topographic map of the Moon to date. It will continue to be updated as more data is acquired.
On March 15, 2011, the final set of data from the exploration phase of the mission was released to the NASA Planetary Data System. The spacecraft's seven instruments delivered more than 192 terabytes of data. LRO has already collected as much data as all other planetary missions combined. [59] This volume of data is possible because the Moon is so close, LRO has its own dedicated ground station, and it doesn't have to share time on the Deep Space Network. Among the latest products is a global map with a resolution of 100 m/pixel (330 ft/pixel) from the Lunar Reconnaissance Orbiter Camera (LROC).
In March 2015, the LROC team reported having imaged the location of an impact whose flash was observed from Earth on March 17, 2013. The team found the crater by going back to images taken in the first year or two and comparing them to images taken after the impact, called temporal pairs. The images revealed splotches, small areas whose reflectance is markedly different from that of the surrounding terrain, presumably from disruption of the surface by recent impacts. [60] [61]
By September 2015, LROC had imaged nearly three-fourths of the lunar surface at high resolution, revealing more than 3,000 lobate scarps. Their global distribution and orientation suggests that the faults are created as the Moon shrinks, with influence by gravitational tidal forces from Earth. [62]
In March 2016, the LROC team reported the use of 14,092 NAC temporal pairs to discover over 47,000 new splotches on the Moon. [63]
In July 2024, the analysis of the radar data obtained by LRO confirmed the presence of an underground cave on the moon accessible from the surface. [64] [65] The cave is said to be about 45 metres wide and at least 80 metres long, and present in the Mare Tranquillitatis (Sea of Tranquility), the ancient lava plain where the Apollo 11 astronauts Neil Armstrong and Buzz Aldrin first set foot on the moon. [66]
The mission maintains a full list of publications with science results on its website. [67]
Lunokhod 2 was the second of two uncrewed lunar rovers that landed on the Moon by the Soviet Union as part of the Lunokhod programme.
A lander is a spacecraft that descends towards, then comes to rest on the surface of an astronomical body other than Earth. In contrast to an impact probe, which makes a hard landing that damages or destroys the probe upon reaching the surface, a lander makes a soft landing after which the probe remains functional.
The Lunar Precursor Robotic Program (LPRP) is a NASA program that uses robotic spacecraft to prepare for future crewed missions to the Moon. The program gathers data such as lunar radiation, surface imaging, areas of scientific interest, temperature and lighting conditions, and potential resource identification.
Chandrayaan-1 was the first Indian lunar probe under the Chandrayaan programme. It was launched by the Indian Space Research Organisation (ISRO) in October 2008, and operated until August 2009. The mission included an orbiter and an impactor. India launched the spacecraft using a PSLV-XL rocket on 22 October 2008 at 00:52 UTC from Satish Dhawan Space Centre, at Sriharikota, Andhra Pradesh. The mission was a major boost to India's space program, as India researched and developed indigenous technology to explore the Moon. The vehicle was inserted into lunar orbit on 8 November 2008.
A Moon landing or lunar landing is the arrival of a spacecraft on the surface of the Moon, including both crewed and robotic missions. The first human-made object to touch the Moon was Luna 2 in 1959.
Lunar water is water that is present on the Moon. The search for the presence of lunar water has attracted considerable attention and motivated several recent lunar missions, largely because of water's usefulness in making long-term lunar habitation feasible.
The physical exploration of the Moon began when Luna 2, a space probe launched by the Soviet Union, made a deliberate impact on the surface of the Moon on September 14, 1959. Prior to that the only available means of lunar exploration had been observations from Earth. The invention of the optical telescope brought about the first leap in the quality of lunar observations. Galileo Galilei is generally credited as the first person to use a telescope for astronomical purposes, having made his own telescope in 1609, the mountains and craters on the lunar surface were among his first observations using it.
The Lunar Crater Observation and Sensing Satellite (LCROSS) was a robotic spacecraft operated by NASA. The mission was conceived as a low-cost means of determining the nature of hydrogen detected at the polar regions of the Moon. Launched immediately after discovery of lunar water by Chandrayaan-1, the main LCROSS mission objective was to further explore the presence of water in the form of ice in a permanently shadowed crater near a lunar polar region. It was successful in confirming water in the southern lunar crater Cabeus.
Third-party evidence for Apollo Moon landings is evidence, or analysis of evidence, about the Moon landings that does not come from either NASA or the U.S. government, or the Apollo Moon landing hoax theorists. This evidence provides independent confirmation of NASA's account of the six Apollo program Moon missions flown between 1969 and 1972.
A rover is a planetary surface exploration device designed to move over the rough surface of a planet or other planetary mass celestial bodies. Some rovers have been designed as land vehicles to transport members of a human spaceflight crew; others have been partially or fully autonomous robots. Rovers are typically created to land on another planet via a lander-style spacecraft, tasked to collect information about the terrain, and to take crust samples such as dust, soil, rocks, and even liquids. They are essential tools in space exploration.
Chandrayaan-2 is the second lunar exploration mission developed by the Indian Space Research Organisation (ISRO) after Chandrayaan-1. It consists of a lunar orbiter, the Vikram lunar lander, and the Pragyan rover, all of which were developed in India. The main scientific objective is to map and study the variations in lunar surface composition, as well as the location and abundance of lunar water.
The Moon Impact Probe (MIP) developed by the Indian Space Research Organisation (ISRO), India's national space agency, was a lunar probe that was released by ISRO's Chandrayaan-1 lunar remote sensing orbiter which in turn was launched, on 22 October 2008, aboard a modified version of ISRO's Polar Satellite Launch Vehicle. It discovered the presence of water on the Moon.
The lunar south pole is the southernmost point on the Moon. It is of interest to scientists because of the occurrence of water ice in permanently shadowed areas around it. The lunar south pole region features craters that are unique in that the near-constant sunlight does not reach their interior. Such craters are cold traps that contain fossil records of hydrogen, water ice, and other volatiles dating from the early Solar System. In contrast, the lunar north pole region exhibits a much lower quantity of similarly sheltered craters.
Lunar IceCube is a NASA nanosatellite orbiter mission that was intended to prospect, locate, and estimate amount and composition of water ice deposits on the Moon for future exploitation. It was launched as a secondary payload mission on Artemis 1, the first flight of the Space Launch System (SLS), on 16 November 2022. As of February 2023 it is unknown whether NASA team has contact with satellite or not.
The following outline is provided as an overview of and topical guide to the Moon:
Beresheet was a demonstrator of a small robotic lunar lander and lunar probe operated by SpaceIL and Israel Aerospace Industries. Its aims included inspiring youth and promoting careers in science, technology, engineering, and mathematics (STEM), and landing its magnetometer, time capsule, and laser retroreflector on the Moon. The lander's gyroscopes failed on 11 April 2019 causing the main engine to shut off, which resulted in the lander crashing on the Moon. Its final resting position is 32.5956°N, 19.3496°E.
Lunar Trailblazer is a planned small lunar orbiter, part of NASA's SIMPLEx program, that will detect and map water on the lunar surface to determine how its form, abundance, and location relate to geology. Its mission is to aid in the understanding of lunar water and the Moon's water cycle. Lunar Trailblazer is currently slated to launch in 2024 as a secondary payload on the IM-2 mission. The Principal Investigator (PI) of the mission is Bethany Ehlmann, a professor at Caltech.