GRAIL

Last updated
   GRAIL-A ·   Moon  ·   Earth
GRAIL-transit-Earth-Moon GRAIL-transit-Earth-Moon.png
GRAIL-transit-Earth-Moon
Animation of GRAIL-A's trajectory around Moon from 31 December 2011 to 30 April 2012

GRAIL-A *
Moon Animation of GRAIL-A trajectory around Moon.gif
Animation of GRAIL-A's trajectory around Moon from 31 December 2011 to 30 April 2012
   GRAIL-A ·   Moon

Unlike the Apollo program missions, which took three days to reach the Moon, GRAIL made use of a three- to four-month low-energy trans-lunar cruise well outside the Moon's orbit and passing near the Sun-Earth Lagrange point L1 before looping back to rendezvous with the Moon. This extended and circuitous trajectory enabled the mission to reduce fuel requirements, protect instruments and reduce the velocity of the two spacecraft at lunar arrival to help achieve the extremely low 50 km (31 mi) orbits with separation between the spacecraft (arriving 25 hours apart) of 175 to 225 km (109 to 140 mi). [22] [29] The very tight tolerances in the flight plan left little room for error correction leading to a launch window lasting one second and providing only two launch opportunities per day. [28]

Science phase

The primary science phase of GRAIL lasted for 88 days, from 7 March 2012 to 29 May 2012. It was followed by a second science phase that ran from 8 Aug 2012 into early Dec 2012.

The gravity mapping technique was similar to that used by Gravity Recovery and Climate Experiment (GRACE), and the spacecraft design was based on XSS-11. [3]

The orbital insertion dates were December 31, 2011 (for GRAIL-A) and January 1, 2012 (for GRAIL-B). [27] The initial lunar orbits were highly elliptical near-polar, and were later lowered to near-circular at about 25-86 km altitude with a period of about 114 minutes. [30]

The spacecraft were operated over the 88-day acquisition phase, divided into three 27.3 day long nadir-pointed mapping cycles. Twice each day there was an 8-hour pass in view of the Deep Space Network for transmission of science and "E/PO MoonKam" data. [31]

The first student-requested MoonKam images were taken by Ebb from 2012 March 15–17 and downlinked to Earth March 20. More than 2,700 schools spanning 52 countries were using the MoonKAM cameras. [32]

Footage of LRO by MoonKam

Flow's MoonKam camera captured LRO as it flew by at a distance of about 12 miles (20 km) on May 3. It's the first footage of a moon-orbiting robotic spacecraft taken by another one. [33]

Terminal phase

Ebb and Flow's Final Moments.jpg
Ebb and Flow's final moments.
GRAIL's Final Resting Spot.jpg
GRAIL's final resting spot.
This animation shows the last three orbits of the spacecraft, with views of the impact site. The impact occurs on the night side of a waxing crescent Moon, so the view shifts from a natural color Moon to a false-color elevation map.
LRO flies over the north pole of the Moon, where it has a very good view of the GRAIL impact. The second part of this video is the view from LRO through LAMP's slit, showing the impact and the resulting plume.

Final experiment and mission end

At the end of the science phase and a mission extension, the spacecraft were powered down and decommissioned over a five-day period. The spacecraft impacted the lunar surface on December 17, 2012. [31] [34] [35] [36] [37] [38] Both spacecraft impacted an unnamed lunar mountain between Philolaus and Mouchez at 75°37′N26°38′W / 75.62°N 26.63°W / 75.62; -26.63 . Ebb, the lead spacecraft in formation, impacted first. Flow impacted moments later. Each spacecraft was traveling at 3,760 miles per hour (1.68 km/s). A final experiment was conducted during the final days of the mission. Main engines aboard the spacecraft were fired, depleting remaining fuel. Data from that effort will be used by mission planners to validate fuel consumption computer models to improve predictions of fuel needs for future missions. [39] NASA has announced that the crash site will be named after GRAIL collaborator and first American woman in space, Sally Ride. [40]

Moon – Oceanus Procellarum ("Ocean of Storms")
14-236-LunarGrailMission-OceanusProcellarum-Rifts-Overall-20141001.jpg
Ancient rift valleys – rectangular structure (visible – topography – GRAIL gravity gradients) (October 1, 2014).
PIA18822-LunarGrailMission-OceanusProcellarum-Rifts-Overall-20141001.jpg
Ancient rift valleys – context.
PIA18821-LunarGrailMission-OceanusProcellarum-Rifts-Closeup-20141001.jpg
Ancient rift valleys – closeup (artist's concept).

Results

Gravity passes through matter. In addition to surface mass, a high-resolution gravity field gives a blurred, but useful, look below the surface. Analyses of the GRAIL data have produced a series of scientific results for the Moon.

See also

Related Research Articles

<span class="mw-page-title-main">Discovery Program</span> Ongoing solar system exploration program by NASA, mission budgets up to $830 M

The Discovery Program is a series of Solar System exploration missions funded by the U.S. National Aeronautics and Space Administration (NASA) through its Planetary Missions Program Office. The cost of each mission is capped at a lower level than missions from NASA's New Frontiers or Flagship Programs. As a result, Discovery missions tend to be more focused on a specific scientific goal rather than serving a general purpose.

<span class="mw-page-title-main">Mass concentration (astronomy)</span> Region of a planet or moons crust that contains a large positive gravitational anomaly

In astronomy, astrophysics and geophysics, a mass concentration is a region of a planet's or moon's crust that contains a large positive gravity anomaly. In general, the word "mascon" can be used as a noun to refer to an excess distribution of mass on or beneath the surface of an astronomical body, such as is found around Hawaii on Earth. However, this term is most often used to describe a geologic structure that has a positive gravitational anomaly associated with a feature that might otherwise have been expected to have a negative anomaly, such as the "mascon basins" on the Moon.

<i>Lunar Prospector</i> Third mission of the Discovery program; polar orbital reconnaissance of the Moon

Lunar Prospector was the third mission selected by NASA for full development and construction as part of the Discovery Program. At a cost of $62.8 million, the 19-month mission was designed for a low polar orbit investigation of the Moon, including mapping of surface composition including lunar hydrogen deposits, measurements of magnetic and gravity fields, and study of lunar outgassing events. The mission ended July 31, 1999, when the orbiter was deliberately crashed into a crater near the lunar south pole, after the presence of hydrogen was successfully detected.

<span class="mw-page-title-main">GRACE and GRACE-FO</span> Joint American-German space mission to map Earths gravitational field

The Gravity Recovery and Climate Experiment (GRACE) was a joint mission of NASA and the German Aerospace Center (DLR). Twin satellites took detailed measurements of Earth's gravity field anomalies from its launch in March 2002 to the end of its science mission in October 2017. The two satellites were sometimes called Tom and Jerry, a nod to the famous cartoon. The GRACE Follow-On (GRACE-FO) is a continuation of the mission on near-identical hardware, launched in May 2018. On March 19, 2024, NASA announced that the successor to GRACE-FO would be Gravity Recovery and Climate Experiment-Continuity (GRACE-C), to be launched in or after 2028.

<span class="mw-page-title-main">Hertzsprung (crater)</span> Crater on the Moon

Hertzsprung is an enormous lunar impact crater, or impact basin, that is located on the far side of the Moon, beyond the western limb. In dimension, this formation is larger than several of the lunar mare areas on the near side. It lies in the northwestern fringe of the blast radius of the Mare Orientale impact basin. Nearby craters of note include Michelson across the northeast rim, Vavilov across the western rim, and Lucretius to the southeast.

<span class="mw-page-title-main">Moon landing</span> Arrival of a spacecraft on the Moons surface

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.

<i>Juno</i> (spacecraft) Second NASA orbiter mission to Jupiter (2011–Present)

Juno is a NASA space probe orbiting the planet Jupiter. It was built by Lockheed Martin and is operated by NASA's Jet Propulsion Laboratory. The spacecraft was launched from Cape Canaveral Air Force Station on August 5, 2011 UTC, as part of the New Frontiers program. Juno entered a polar orbit of Jupiter on July 5, 2016, UTC, to begin a scientific investigation of the planet. After completing its mission, Juno was originally planned to be intentionally deorbited into Jupiter's atmosphere, but has since been approved to continue orbiting until contact is lost with the spacecraft.

<span class="mw-page-title-main">Near side of the Moon</span> Hemisphere of the Moon facing the Earth

The near side of the Moon is the lunar hemisphere that always faces towards Earth, opposite to the far side. Only one side of the Moon is visible from Earth because the Moon rotates on its axis at the same rate that the Moon orbits the Earth—a situation known as tidal locking.

<span class="mw-page-title-main">Lunar orbit</span> Orbit of an object around the Moon

In astronomy and spaceflight, a lunar orbit is an orbit by an object around Earth's Moon. In general these orbits are not circular. When farthest from the Moon a spacecraft is said to be at apolune, apocynthion, or aposelene. When closest to the Moon it is said to be at perilune, pericynthion, or periselene. These derive from names or epithets of the moon goddess.

<span class="mw-page-title-main">Maria Zuber</span> American astronomer (born 1958)

Maria T. Zuber is an American geophysicist who is the vice president for research at the Massachusetts Institute of Technology, where she also holds the position of the E. A. Griswold Professor of Geophysics in the Department of Earth, Atmospheric and Planetary Sciences. Zuber has been involved in more than half a dozen NASA planetary missions aimed at mapping the Moon, Mars, Mercury, and several asteroids. She was the principal investigator for the Gravity Recovery and Interior Laboratory (GRAIL) Mission, which was managed by NASA's Jet Propulsion Laboratory.

<span class="mw-page-title-main">Low-energy transfer</span> Fuel-efficient orbital maneuver

A low-energy transfer, or low-energy trajectory, is a route in space that allows spacecraft to change orbits using significantly less fuel than traditional transfers. These routes work in the Earth–Moon system and also in other systems, such as between the moons of Jupiter. The drawback of such trajectories is that they take longer to complete than higher-energy (more-fuel) transfers, such as Hohmann transfer orbits.

<span class="mw-page-title-main">Gravitation of the Moon</span>

The acceleration due to gravity on the surface of the Moon is approximately 1.625 m/s2, about 16.6% that on Earth's surface or 0.166 ɡ. Over the entire surface, the variation in gravitational acceleration is about 0.0253 m/s2. Because weight is directly dependent upon gravitational acceleration, things on the Moon will weigh only 16.6% of what they weigh on the Earth.

<span class="mw-page-title-main">Exploration of Jupiter</span> Overview of the exploration of Jupiter the planet and its moons

The exploration of Jupiter has been conducted via close observations by automated spacecraft. It began with the arrival of Pioneer 10 into the Jovian system in 1973, and, as of 2023, has continued with eight further spacecraft missions in the vicinity of Jupiter. All of these missions were undertaken by the National Aeronautics and Space Administration (NASA), and all but two were flybys taking detailed observations without landing or entering orbit. These probes make Jupiter the most visited of the Solar System's outer planets as all missions to the outer Solar System have used Jupiter flybys. On 5 July 2016, spacecraft Juno arrived and entered the planet's orbit—the second craft ever to do so. Sending a craft to Jupiter is difficult, mostly due to large fuel requirements and the effects of the planet's harsh radiation environment.

<span class="mw-page-title-main">InSight</span> NASA Mars lander (2018–2022)

The Interior Exploration using Seismic Investigations, Geodesy and Heat Transport (InSight) mission was a robotic lander designed to study the deep interior of the planet Mars. It was manufactured by Lockheed Martin Space, was managed by NASA's Jet Propulsion Laboratory (JPL), and two of its three scientific instruments were built by European agencies. The mission launched on 5 May 2018 at 11:05:01 UTC aboard an Atlas V-401 launch vehicle and successfully landed at Elysium Planitia on Mars on 26 November 2018 at 19:52:59 UTC. InSight was active on Mars for 1440 sols.

<span class="mw-page-title-main">Europa Clipper</span> Planned NASA space mission to Jupiter

Europa Clipper is a space probe in development by NASA. Planned for launch on 10 October 2024, the spacecraft is being developed to study the Galilean moon Europa through a series of flybys while in orbit around Jupiter. It is the largest spacecraft NASA has ever developed for a planetary mission.

<span class="mw-page-title-main">GRAIL MoonKAM</span>

GRAIL MoonKAM (Moon Knowledge Acquired by Middle school students) was part of NASA’s GRAIL satellite mission to map the Moon’s gravity.

<i>Psyche</i> (spacecraft) Reconnaissance mission of the main belt asteroid 16 Psyche

Psyche is a NASA Discovery Program space mission launched on October 13, 2023 to explore the origin of planetary cores by orbiting and studying the metallic asteroid 16 Psyche beginning in 2029. NASA's Jet Propulsion Laboratory (JPL) manages the project.

<span class="mw-page-title-main">Coulomb-Sarton Basin</span> Feature on the moon

The Coulomb-Sarton Basin is a Pre-Nectarian impact basin on the far side of the Moon. It is named after the crater Coulomb northeast of the center of the basin and the smaller crater Sarton just south of the center. The basin is not obvious on the lunar surface. There are only small fragments of inner rings and a rim, and the most indicative topographic feature is a smooth, low plain at the center.

Rotation and Interior Structure Experiment (RISE) is a radio science experiment onboard InSight Mars lander that will use the spacecraft communication system to provide precise measurements of Mars' rotation and wobble. RISE precisely tracks the location of the lander to measure how much Mars's axis wobbles as it orbits the Sun. These observations will provide new constraints on the core radius and help determine whether the core of Mars is mostly liquid, and which other elements, besides iron, may be present. This study will also help scientists understand why Mars's magnetic field is so weak, as compared to Earth's.

References

  1. 1 2 "Delta II Set to Launch NASA's GRAIL Mission". United Launch Alliance . 2011. Archived from the original on 1 September 2011. Retrieved 2 September 2011.
  2. "The GRAIL Mission: A Fact Sheet". Sally Ride Science. 2010. Archived from the original on 28 April 2010. Retrieved 15 April 2010.
  3. 1 2 Taylor Dinerman (31 December 2007). "Is XSS-11 the answer to America's quest for Operationally Responsive Space?". The Space Review. Retrieved 31 August 2011.
  4. Asif Siddiqi (2018). Beyond Earth: A Chronicle of Deep Space Exploration, 1958–2016 (PDF) (second ed.). NASA History Program Office. ISBN   978-1-626-83043-1 . Retrieved 30 November 2022.
  5. 1 2 3 "About GRAIL". moon.mit.edu. MIT . Retrieved 12 March 2011.
  6. Gail Schontzler (18 January 2012). "Bozeman class wins contest to name satellites orbiting moon". Bozeman Daily Chronicle. Retrieved 18 December 2018.
  7. 1 2 3 D. C. Brown; D. C. Agle; W. L. Mullen (17 January 2012). "Montana Students Submit Winning Names for NASA Lunar Spacecraft". nasa.gov. NASA. Archived from the original on 25 February 2021. Retrieved 18 January 2012.
  8. Delta II: The Industry Workhorse (PDF). United Launch Alliance (Report). 2010. Archived from the original (PDF) on 30 September 2011. Retrieved 2 August 2011.
  9. Grey Hautaluoma (10 December 2007). "New NASA Mission to Reveal Moon's Internal Structure and Evolution". nasa.gov. NASA. Archived from the original on 24 February 2021. Retrieved 31 August 2011.
  10. Laura Dattaro (10 September 2011). "Moon-bound twin GRAIL spacecraft launch success". EarthSky.org. Retrieved 23 July 2024.
  11. 1 2 "GRAIL Twins crash into the Moon to complete highly successful Mission". Spaceflight101.com. 19 March 2013. Archived from the original on 11 February 2015. Retrieved 23 July 2024.
  12. D. C. Agle; D. C. Brown; C. McCall (31 December 2011). "First of NASA's GRAIL Spacecraft Enters Moon Orbit". nasa.gov. NASA. Archived from the original on 25 February 2021. Retrieved 1 January 2012.
  13. 1 2 "GRAIL Launch Press Kit" (PDF). solarsystem.nasa.gov. NASA. Archived from the original (PDF) on 5 October 2012. Retrieved 31 August 2011.
  14. M. T. Zuber; D. E. Smith; S. W. Asmar; Alomon; A. S. Konopliv; F. G. Lemoine; et al. (19–23 March 2012). Gravity Recovery and Interior Laboratory (GRAIL) Mission: Status at the Initiation of the Science Mapping Phase. 43rd Lunar and Planetary Science Conference. Texas, USA: NASA. GSFC.CP.00105.2012.
  15. Emil Kolawole (17 December 2012). "NASA to send probes smashing into the Moon" . The Washington Post . Retrieved 24 July 2024.
  16. 1 2 A. S. Konopliv; R. S. Park; D. N. Yuan; S. W. Asmar; M. M. Watkins; et al. (2013). "The JPL lunar gravity field to spherical harmonic degree 660 from the GRAIL Primary Mission: GRAIL LUNAR GRAVITY". Journal of Geophysical Research: Planets. 118 (7): 1415–1434. Bibcode:2013JGRE..118.1415K. doi:10.1002/jgre.20097. hdl: 1721.1/85858 . S2CID   16559256.
  17. 1 2 F. G. Lemoine; S. Goossens; T. J. Sabaka; J. B. Nicholas; E. Mazarico; et al. (2013). "High‒degree gravity models from GRAIL primary mission data". Journal of Geophysical Research: Planets. 118 (8): 1676–1698. Bibcode:2013JGRE..118.1676L. doi: 10.1002/jgre.20118 . hdl: 2060/20140010292 . ISSN   2169-9097.
  18. 1 2 A. S. Konopliv; R. S. Park; D. N. Yuan; S. W. Asmar; M. M. Watkins; et al. (2014). "High-resolution lunar gravity fields from the GRAIL Primary and Extended Missions". Geophysical Research Letters. 41 (5): 1452–1458. Bibcode:2014GeoRL..41.1452K. doi: 10.1002/2013GL059066 .
  19. 1 2 F. G. Lemoine; S. Goossens; T. J. Sabaka; J. B. Nicholas; E. Mazarico; et al. (28 May 2014). "GRGM900C: A degree 900 lunar gravity model from GRAIL primary and extended mission data". Geophysical Research Letters. 41 (10): 3382–3389. Bibcode:2014GeoRL..41.3382L. doi:10.1002/2014GL060027. PMC   4459205 . PMID   26074638.
  20. D. C. Agle; Caroline McCall (31 August 2012). "NASA's GRAIL Moon Twins Begin Extended Mission Science". jpl.nasa.gov. NASA / JPL . Retrieved 21 July 2013.
  21. D. C. Agle; D. C. Brown; S. McDonnell (5 December 2012). "NASA's GRAIL Creates Most Accurate Moon Gravity Map". jpl.nasa.gov. NASA / JPL . Retrieved 21 July 2013.
  22. 1 2 "GRAIL: Mission Overview". moon.mit.edu. MIT . Retrieved 10 September 2011.
  23. 1 2 "GRAIL: Spacecraft and Payload". moon.mit.edu. MIT . Retrieved 24 July 2024.
  24. "GRAIL: Mission Operations & Data Processing". moon.mit.edu. MIT. Archived from the original on 5 March 2012. Retrieved 14 December 2012.
  25. "About GRAIL MoonKAM". Sally Ride Science. 2010. Archived from the original on 27 April 2010. Retrieved 15 April 2010.
  26. "GRAIL (Gravity Recovery and Interior Laboratory)". eoPortal.org. Retrieved 3 December 2022.
  27. 1 2 3 4 5 6 William Harwood (10 September 2011). "NASA launches GRAIL lunar probes". CBS News . Archived from the original on 4 November 2012. Retrieved 11 September 2011.
  28. 1 2 Justin Ray (17 August 2011). "GRAIL Launch Window Chart". Spaceflight Now. Retrieved 9 September 2011.
  29. "GRAIL (Ebb and Flow) - NASA Science". science.nasa.gov. NASA . Retrieved 10 September 2011.
  30. D. C. Agle (27 March 2012). "Flying Formation - Around the Moon at 3,600 MPH". jpl.nasa.gov. NASA / JPL . Retrieved 24 July 2024.
  31. 1 2 "GRAIL: Mission Design". moon.mit.edu. MIT . Retrieved 24 July 2024.
  32. D. C. Agle; D. C. Brown; C. McCall (22 March 2012). "NASA GRAIL Returns First Student-Selected Moon Images". jpl.nasa.gov. NASA / JPL . Retrieved 24 July 2014.
  33. "Spacecraft Pass Each Other at the Moon". science.nasa.gov. NASA. 13 December 2012. Retrieved 24 July 2024.
  34. D. C. Agle (17 December 2012). "NASA GRAIL Twins Complete Their Moon Impact". jpl.nasa.gov. NASA / JPL . Retrieved 18 December 2012.
  35. Mike Wall (13 December 2012). "Twin GRAIL probes readied for crash into Moon". NBC News . Retrieved 18 February 2013.[ dead link ]
  36. Mike Wall (12 December 2012). "Twin NASA Probes to Crash into Moon Next Week". Space.com. Retrieved 18 February 2013.
  37. "Twin NASA spacecraft prepare to crash into moon". Phys.org. 13 December 2012. Retrieved 14 December 2012.
  38. Alex Knapp (14 December 2012). "NASA Prepares To Crash Its Probes Into The Moon". Forbes . Retrieved 15 December 2012.
  39. D. C. Agle; D. C. Brown; S. McDonnell (13 December 2012). "NASA Probes Prepare for Mission-Ending Moon Impact". jpl.nasa.gov. NASA / JPL . Retrieved 18 February 2013.
  40. Mike Wall (18 December 2012). "Moon Probes' Crash Site Named After Sally Ride". Space.com. Retrieved 18 February 2013.
  41. M. T. Zuber; D. E. Smith; M. M. Watkins; S. W. Asmar; A. S. Konopliv; et al. (2013). "Gravity Field of the Moon from the Gravity Recovery and Interior Laboratory (GRAIL) Mission". Science. 339 (6120): 668–671. Bibcode:2013Sci...339..668Z. doi:10.1126/science.1231507. ISSN   0036-8075. PMID   23223395. S2CID   206545934.
  42. M. A. Wieczorek; G. A. Neumann; F. Nimmo; W. S. Kiefer; G. J. Taylor; et al. (2013). "The Crust of the Moon as Seen by GRAIL". Science . 339 (6120): 671–675. Bibcode:2013Sci...339..671W. doi:10.1126/science.1231530. ISSN   0036-8075. PMC   6693503 . PMID   23223394.
  43. J. C. Andrews-Hanna; S. W. Asmar; J. W. Head; W. S. Kiefer; A. S. Konopliv; et al. (2013). "Ancient Igneous Intrusions and Early Expansion of the Moon Revealed by GRAIL Gravity Gradiometry". Science . 339 (6120): 675–678. Bibcode:2013Sci...339..675A. doi:10.1126/science.1231753. ISSN   0036-8075. PMID   23223393. S2CID   18004181.
  44. J. G. Williams; A. S. Konopliv; D. H. Boggs; R. S. Park; D. N. Yuan; et al. (2014). "Lunar interior properties from the GRAIL mission". Journal of Geophysical Research: Planets. 119 (7): 1546–1578. Bibcode:2014JGRE..119.1546W. doi: 10.1002/2013JE004559 . S2CID   7045590.
  45. G. A. Neumann; M. T. Zuber; M. A. Wieczorek; J. W. Head; D. M. H. Baker; et al. (2015). "Lunar impact basins revealed by Gravity Recovery and Interior Laboratory measurements". Science Advances. 1 (9): e1500852. Bibcode:2015SciA....1E0852N. doi:10.1126/sciadv.1500852. ISSN   2375-2548. PMC   4646831 . PMID   26601317.
  46. P. M. Mueller; W. L. Sjogren (1968). "Mascons: Lunar Mass Concentrations". Science . 161 (3842): 680–684. Bibcode:1968Sci...161..680M. doi:10.1126/science.161.3842.680. ISSN   0036-8075. PMID   17801458. S2CID   40110502.
  47. I. Matsuyama; F. Nimmo; J. T. Keane; N. H. Chan; et al. (2016). "GRAIL, LLR, and LOLA constraints on the interior structure of the Moon". Geophysical Research Letters. 43 (16): 8365–8375. Bibcode:2016GeoRL..43.8365M. doi:10.1002/2016GL069952. hdl: 10150/621595 . S2CID   36834256.
  48. M. T. Zuber; D. E. Smith; G. A. Neumann; S. Goossens; J. C. Andrews-Hanna; et al. (2016). "Gravity field of the Orientale basin from the Gravity Recovery and Interior Laboratory Mission". Science . 354 (6311): 438–441. Bibcode:2016Sci...354..438Z. doi:10.1126/science.aag0519. ISSN   0036-8075. PMC   7462089 . PMID   27789835.
Gravity Recovery and Interior Laboratory
GRAIL.jpg
Artist's interpretation of the GRAIL tandem spacecraft above the lunar surface.
NamesGRAIL
Mission type Lunar orbiters
Operator NASA  / JPL [1] [2]
COSPAR ID 2011-046A
2011-046B
SATCAT no. 37801
37802
Website moon.mit.edu
Mission duration1 year, 3 months and 7 days
Spacecraft properties
Bus XSS-11 [3]
Manufacturer MIT
Lockheed Martin
Launch mass202.4 kg (each) [4]
Dry mass132.6 kg (292 lb)
Power(Solar array / Li-ion battery)
Start of mission
Launch dateSeptember 10, 2011, 13:08:52.775 (2011-09-10UTC13:08:52Z) UTC
Rocket Delta II 7920H-10
D-356
Launch site Cape Canaveral SLC-17B
Contractor United Launch Alliance
Entered serviceDecember 31, 2011 (Ebb)
January 1, 2012 (Flow)
End of mission
DisposalDeorbited
Decay dateDecember 17, 2012
Orbital parameters
Reference system Selenocentric
Regime Polar orbit [5]
Semi-major axis 1,788.0 km (1,111.0 mi)
Periselene altitude 25 km (16 mi)
Aposelene altitude 86 km (53 mi)
Period 113 minutes
Lunar impactor
Spacecraft componentEbb
Impact dateDecember 17, 2012, 22:28:51 UTC
Impact site 75°36′30″N33°24′15″E / 75.6083°N 33.4043°E / 75.6083; 33.4043