LCROSS
Encyclopedia
The Lunar Crater Observation and Sensing Satellite (LCROSS) was a robotic spacecraft
Robotic spacecraft
A robotic spacecraft is a spacecraft with no humans on board, that is usually under telerobotic control. A robotic spacecraft designed to make scientific research measurements is often called a space probe. Many space missions are more suited to telerobotic rather than crewed operation, due to...

 operated by NASA
NASA
The National Aeronautics and Space Administration is the agency of the United States government that is responsible for the nation's civilian space program and for aeronautics and aerospace research...

. The mission was conceived as a low-cost means of determining the nature of hydrogen
Hydrogen
Hydrogen is the chemical element with atomic number 1. It is represented by the symbol H. With an average atomic weight of , hydrogen is the lightest and most abundant chemical element, constituting roughly 75% of the Universe's chemical elemental mass. Stars in the main sequence are mainly...

 detected at the polar regions of the moon
Moon
The Moon is Earth's only known natural satellite,There are a number of near-Earth asteroids including 3753 Cruithne that are co-orbital with Earth: their orbits bring them close to Earth for periods of time but then alter in the long term . These are quasi-satellites and not true moons. For more...

. The main LCROSS mission objective was to explore the presence of water
Water
Water is a chemical substance with the chemical formula H2O. A water molecule contains one oxygen and two hydrogen atoms connected by covalent bonds. Water is a liquid at ambient conditions, but it often co-exists on Earth with its solid state, ice, and gaseous state . Water also exists in a...

 ice in a permanently shadowed crater near a lunar
Moon
The Moon is Earth's only known natural satellite,There are a number of near-Earth asteroids including 3753 Cruithne that are co-orbital with Earth: their orbits bring them close to Earth for periods of time but then alter in the long term . These are quasi-satellites and not true moons. For more...

 polar region. It was successful in discovering water in the southern lunar crater Cabeus
Cabeus (crater)
Cabeus is a lunar crater that is located about from the south pole of the Moon. At this location the crater is seen obliquely from Earth, and it is almost perpetually in deep shadow due to lack of sunlight. Hence, not much detail can be seen of this crater, even from orbit...

.

It was launched together with the Lunar Reconnaissance Orbiter
Lunar Reconnaissance Orbiter
The Lunar Precursor Robotic Program is a program of robotic spacecraft missions which NASA will use to prepare for future human spaceflight missions to the Moon. Two LPRP missions, the Lunar Reconnaissance Orbiter and the Lunar Crater Observation and Sensing Satellite , were launched in June 2009...

 (LRO) on June 18, 2009, as part of the shared Lunar Precursor Robotic Program, the first American
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...

 mission to the Moon
Moon
The Moon is Earth's only known natural satellite,There are a number of near-Earth asteroids including 3753 Cruithne that are co-orbital with Earth: their orbits bring them close to Earth for periods of time but then alter in the long term . These are quasi-satellites and not true moons. For more...

 in over ten years. Together, LCROSS and LRO form the vanguard of NASA's return to the Moon, and are expected to influence United States government
Federal government of the United States
The federal government of the United States is the national government of the constitutional republic of fifty states that is the United States of America. The federal government comprises three distinct branches of government: a legislative, an executive and a judiciary. These branches and...

 decisions on whether or not to colonize the Moon
Colonization of the Moon
The colonization of the Moon is the proposed establishment of permanent human communities on the Moon. Advocates of space exploration have seen settlement of the Moon as a logical step in the expansion of humanity beyond the Earth. Recent indication that water might be present in noteworthy...

.

LCROSS was designed to collect and relay data from the impact and debris plume resulting from the launch vehicle's spent Centaur
Centaur (rocket stage)
Centaur is a rocket stage designed for use as the upper stage of space launch vehicles. Centaur boosts its satellite payload to geosynchronous orbit or, in the case of an interplanetary space probe, to or near to escape velocity...

 upper stage (and data collecting Shepherding Spacecraft) striking the crater Cabeus
Cabeus (crater)
Cabeus is a lunar crater that is located about from the south pole of the Moon. At this location the crater is seen obliquely from Earth, and it is almost perpetually in deep shadow due to lack of sunlight. Hence, not much detail can be seen of this crater, even from orbit...

 near the south pole of the Moon
Moon
The Moon is Earth's only known natural satellite,There are a number of near-Earth asteroids including 3753 Cruithne that are co-orbital with Earth: their orbits bring them close to Earth for periods of time but then alter in the long term . These are quasi-satellites and not true moons. For more...

.

Centaur had nominal impact mass of 2,305 kg (5,081 lb), and an impact velocity of about 10000 km/h (6,213.7 mph).

LCROSS suffered a malfunction on August 22, depleting half of its fuel and leaving very little fuel margin in the spacecraft.

Centaur impacted successfully on October 9, 2009, at 11:31 UTC. The Shepherding Spacecraft descended through Centaur's ejectate plume, collected and relayed data, impacting six minutes later at 11:37 UTC.

Mission

LCROSS was a fast-track, low-cost companion mission to the LRO. The LCROSS payload was added after NASA moved the LRO from the Delta II
Delta II
Delta II was an American space launch system, originally designed and built by McDonnell Douglas. Delta II is part of the Delta rocket family and was in service from 1989 until November 1, 2011...

 to a larger launch vehicle. It was chosen from 19 other proposals. LCROSS's mission was dedicated to late American broadcaster Walter Cronkite
Walter Cronkite
Walter Leland Cronkite, Jr. was an American broadcast journalist, best known as anchorman for the CBS Evening News for 19 years . During the heyday of CBS News in the 1960s and 1970s, he was often cited as "the most trusted man in America" after being so named in an opinion poll...

.

LCROSS launched with the LRO
Lunar Reconnaissance Orbiter
The Lunar Precursor Robotic Program is a program of robotic spacecraft missions which NASA will use to prepare for future human spaceflight missions to the Moon. Two LPRP missions, the Lunar Reconnaissance Orbiter and the Lunar Crater Observation and Sensing Satellite , were launched in June 2009...

 aboard an Atlas V
Atlas V
Atlas V is an active expendable launch system in the Atlas rocket family. Atlas V was formerly operated by Lockheed Martin, and is now operated by the Lockheed Martin-Boeing joint venture United Launch Alliance...

 rocket from Cape Canaveral, Florida
Cape Canaveral, Florida
Cape Canaveral is a city in Brevard County, Florida, United States. The population was 8,829 at the 2000 census. As of 2008, the estimated population according to the U.S. Census Bureau was 10,147...

, on June 18, 2009, at 21:32 UTC (17:32 EDT
Eastern Time Zone
The Eastern Time Zone of the United States and Canada is a time zone that falls mostly along the east coast of North America. Its UTC time offset is −5 hrs during standard time and −4 hrs during daylight saving time...

). On June 23, four and a half days after launch, LCROSS and its attached Centaur booster rocket
Centaur (rocket stage)
Centaur is a rocket stage designed for use as the upper stage of space launch vehicles. Centaur boosts its satellite payload to geosynchronous orbit or, in the case of an interplanetary space probe, to or near to escape velocity...

 successfully completed a lunar swingby and entered into polar Earth orbit
Polar orbit
A polar orbit is an orbit in which a satellite passes above or nearly above both poles of the body being orbited on each revolution. It therefore has an inclination of 90 degrees to the equator...

 with a period of 37 days, positioning LCROSS for impact on a lunar pole.

Early in the morning on August 22, 2009, LCROSS ground controllers discovered an anomaly caused by a sensor problem, which had resulted in the spacecraft burning through 140 kilograms (309 pounds) of fuel, more than half of the fuel remaining at the time. According to Dan Andrews, the LCROSS project manager, "Our estimates now are if we pretty much baseline the mission, meaning just accomplish the things that we have to [do] to get the job done with full mission success, we're still in the black on propellant, but not by a lot."
Lunar impacts, after approximately three orbits, occurred on October 9, 2009, with the Centaur crashing into the Moon at 11:31 UTC and the Shepherding Spacecraft following a few minutes later. The mission team initially announced that Cabeus A would be the target crater for the LCROSS dual impacts, but later refined the target to be the larger, main Cabeus crater.

On its final approach to the Moon, the Shepherding Spacecraft and Centaur separated October 9, 2009, at 01:50 UTC. The Centaur upper stage acted as a heavy impactor to create a debris plume that rose above the lunar surface. Following four minutes after impact of the Centaur upper stage, the Shepherding Spacecraft flew through this debris plume, collecting and relaying data back to Earth before it struck the lunar surface to produce a second debris plume. The impact velocity was projected to be 9000 km/h (5,592.3 mph). The actual impact was later calculated to have been over 10000 km/h (6,213.7 mph).

The Centaur impact was expected to excavate more than 350 metric tons (385.8 ST) of lunar material and create a crater about 20 m (65 ft) in diameter to a depth of about 4 m (13.1 ft). The Shepherding Spacecraft impact was projected to excavate an estimated 150 metric tons (165.3 ST) and create a crater 14 m (45.9 ft) in diameter to a depth of about 2 m (6 ft). Most of the material in the Centaur debris plume was expected to remain at (lunar) altitudes below 10 km (6 mi).

It was hoped that spectral analysis
Spectrum analysis
Spectrum, also known as emission spectrochemical analysis, is the original scientific method of charting and analyzing the chemical properties of matter and gases by looking at the bands in their optical spectrum...

 of the resulting impact plume would help to confirm preliminary findings by the Clementine
Clementine mission
Clementine was a joint space project between the Ballistic Missile Defense Organization and NASA...

 and Lunar Prospector
Lunar Prospector
The Lunar Prospector mission was the third 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 and possible...

 missions which hinted that there may be water ice
Lunar ice
Lunar water is water that is present on the Moon. Liquid water cannot persist at the Moon's surface, and water vapour is quickly decomposed by sunlight and lost to outer space...

 in the permanently shadowed regions. Mission scientists expected that the Centaur impact plume would be visible through amateur-class telescopes with apertures as small as 25 to 30 cm (10 to 12 inches).
But no plume was observed by such amateur telescopes. Even world class telescopes such as the Hale telescope
Hale telescope
The Hale Telescope is a , 3.3 reflecting telescope at the Palomar Observatory in California, named after astronomer George Ellery Hale. With funding from the Rockefeller Foundation, he orchestrated the planning, design, and construction of the observatory, but did not live to see its commissioning...

, equipped with adaptive optics, did not detect the plume. The plume may have still occurred but at a small scale not detectable from earth.
Both impacts were also monitored by Earth-based observatories and by orbital assets, such as the Hubble Space Telescope
Hubble Space Telescope
The Hubble Space Telescope is a space telescope that was carried into orbit by a Space Shuttle in 1990 and remains in operation. A 2.4 meter aperture telescope in low Earth orbit, Hubble's four main instruments observe in the near ultraviolet, visible, and near infrared...

.

Whether or not LCROSS would find water had been stated to be influential in whether or not the United States government pursues creating a Moon base
Colonization of the Moon
The colonization of the Moon is the proposed establishment of permanent human communities on the Moon. Advocates of space exploration have seen settlement of the Moon as a logical step in the expansion of humanity beyond the Earth. Recent indication that water might be present in noteworthy...

. On November 13, 2009, NASA confirmed that water was detected after the Centaur impacted the crater.

Spacecraft

The LCROSS mission took advantage of the structural capabilities of the Evolved Expendable Launch Vehicle (EELV) Secondary Payload Adapter (ESPA)
EELV Secondary Payload Adapter
The EELV Secondary Payload Adapter is an interstage adapter ring utilized for launching secondary payloads on US DoD space missions that utilize the Evolved Expendable Launch Vehicles Atlas V and Delta IV. This reduces launch costs for the primary mission and enables secondary and even tertiary...

 ring used to attach LRO to the Centaur upper stage rocket. Mounted on the outside of the ESPA were six panels that hold the spacecraft's science payload, command and control systems, communications equipment, batteries, and solar panels. A small monopropellant propulsion system
Monopropellant rocket
A monopropellant rocket is a rocket that uses a single chemical as its propellant.-Chemical-reaction monopropellant rockets:...

 was mounted inside of the ring. Also attached were two S Band
S band
The S band is defined by an IEEE standard for radio waves with frequencies that range from 2 to 4 GHz, crossing the conventional boundary between UHF and SHF at 3.0 GHz. It is part of the microwave band of the electromagnetic spectrum...

 omnidirectional antenna
Omnidirectional antenna
In radio communication, an omnidirectional antenna is an antenna which radiates radio wave power uniformly in all directions in one plane, with the radiated power decreasing with elevation angle above or below the plane, dropping to zero on the antenna's axis. This radiation pattern is often...

s and two medium-gain antennas. The mission's strict schedule, mass, and budget constraints posed difficult challenges to engineering teams from NASA Ames Research Center (ARC) and Northrop Grumman
Northrop Grumman
Northrop Grumman Corporation is an American global aerospace and defense technology company formed by the 1994 purchase of Grumman by Northrop. The company was the fourth-largest defense contractor in the world as of 2010, and the largest builder of naval vessels. Northrop Grumman employs over...

. Their creative thinking led to a unique use of the ESPA ring and innovative sourcing of other spacecraft components. Usually, the ESPA ring is used as a platform to hold six small deployable satellites; for LCROSS, it became the backbone of the satellite, a first for the ring. LCROSS also took advantage of commercially available instruments and used many of the already-flight-verified components used on LRO
Lunar Reconnaissance Orbiter
The Lunar Precursor Robotic Program is a program of robotic spacecraft missions which NASA will use to prepare for future human spaceflight missions to the Moon. Two LPRP missions, the Lunar Reconnaissance Orbiter and the Lunar Crater Observation and Sensing Satellite , were launched in June 2009...

.
LCROSS is managed by NASA's ARC and was built by Northrop Grumman
Northrop Grumman
Northrop Grumman Corporation is an American global aerospace and defense technology company formed by the 1994 purchase of Grumman by Northrop. The company was the fourth-largest defense contractor in the world as of 2010, and the largest builder of naval vessels. Northrop Grumman employs over...

. The LCROSS preliminary design review was completed on September 8, 2006. The LCROSS mission passed its Mission Confirmation Review on February 2, 2007, and its Critical Design Review on February 22, 2007.
After assembly and testing at Ames, the instrument payload, provided by Ecliptic Enterprises Corporation, was shipped to Northrop Grumman on January 14, 2008, for integration with the spacecraft. LCROSS passed its review on February 12, 2009.

Instruments

The LCROSS science instrument payload, provided by NASA's ARC, consisted of a total of nine instruments: one visible, two near infrared, and two mid-infrared cameras; one visible and two near-infrared spectrometers; and a photometer. A data handling unit (DHU) collected the information from each instrument for transmission back to LCROSS Mission Control. Because of the schedule and budget constraints, LCROSS took advantage of rugged, commercially available components. The individual instruments went through a rigorous testing cycle that simulated launch and flight conditions, identifying design weaknesses and necessary modifications for use in space, at which point the manufacturers were allowed to modify their designs.

Results

The impact was not as visually prominent as had been anticipated. Project manager Dan Andrews believed that this was due to pre-crash simulations that exaggerated the plume's prominence. Because of data bandwidth issues, the exposures were kept short, which made the plume difficult to see in the images in the visible spectra. This resulted in the need for image processing to increase clarity. The infrared camera also captured a thermal signature of the booster's impact.

Presence of water

On 13 November 2009, NASA reported that multiple lines of evidence show water was present in both the high-angle vapor plume and the ejecta curtain created by the LCROSS Centaur impact. , the concentration and distribution of water and other substances required more analysis. Additional confirmation came from an emission in the ultraviolet spectrum that was attributed to hydroxyl
Hydroxyl
A hydroxyl is a chemical group containing an oxygen atom covalently bonded with a hydrogen atom. In inorganic chemistry, the hydroxyl group is known as the hydroxide ion, and scientists and reference works generally use these different terms though they refer to the same chemical structure in...

 fragments, a product from the break-up of water by sunlight.
Analysis of the spectra indicate that a reasonable estimate of the concentration of water in the frozen regolith is on the order of one percent. Evidence from other missions suggests that this may have been a relatively dry spot, as thick deposits of relatively pure ice appear to present themselves in other craters. A later, more definitive, analysis found the concentration of water to be "5.6 ± 2.9% by mass."

Imagery

Awards

LCROSS has received numerous awards for its technical, managerial, and scientific accomplishments.
  • 2010: Northrop Grumman
    Northrop Grumman
    Northrop Grumman Corporation is an American global aerospace and defense technology company formed by the 1994 purchase of Grumman by Northrop. The company was the fourth-largest defense contractor in the world as of 2010, and the largest builder of naval vessels. Northrop Grumman employs over...

     Northrop Grumman Corporate 2010 Award for Excellence (Northrop Grumman team)
  • 2010: Popular Mechanics
    Popular Mechanics
    Popular Mechanics is an American magazine first published January 11, 1902 by H. H. Windsor, and has been owned since 1958 by the Hearst Corporation...

     magazine's 2010 Breakthrough Award for innovation in science and technology.
  • 2010: NASA
    NASA
    The National Aeronautics and Space Administration is the agency of the United States government that is responsible for the nation's civilian space program and for aeronautics and aerospace research...

     Honor Award – Group Achievement, (LCROSS Science Team)
  • 2010: NASA
    NASA
    The National Aeronautics and Space Administration is the agency of the United States government that is responsible for the nation's civilian space program and for aeronautics and aerospace research...

     Honor Award – Group Achievement, (LCROSS Mission Operations Team)
  • 2010: NASA
    NASA
    The National Aeronautics and Space Administration is the agency of the United States government that is responsible for the nation's civilian space program and for aeronautics and aerospace research...

     Honor Award – Group Achievement, for “outstanding professionalism, innovation in outreach and education, and for integrating outreach for two missions into one launch.” (LRO/LCROSS/LPRP EPO teams)
  • 2010: NASA
    NASA
    The National Aeronautics and Space Administration is the agency of the United States government that is responsible for the nation's civilian space program and for aeronautics and aerospace research...

     Honor Award - Outstanding Leadership Medal, (Dan Andrews & Tony Colaprete)
  • 2010: NASA
    NASA
    The National Aeronautics and Space Administration is the agency of the United States government that is responsible for the nation's civilian space program and for aeronautics and aerospace research...

     Honor Award - Group Achievement, LCROSS Science and Payload Team
  • 2010: NASA
    NASA
    The National Aeronautics and Space Administration is the agency of the United States government that is responsible for the nation's civilian space program and for aeronautics and aerospace research...

     Ames Honor Award, category “Exceptional Achievement” (Rusty Hunt & Ken Galal)
  • 2010: Northrop Grumman
    Northrop Grumman
    Northrop Grumman Corporation is an American global aerospace and defense technology company formed by the 1994 purchase of Grumman by Northrop. The company was the fourth-largest defense contractor in the world as of 2010, and the largest builder of naval vessels. Northrop Grumman employs over...

     AS Sector President’s Award, category “Operational Excellence” (Northrop Grumman team)
  • 2010: Aviation Week Laureate Award Nominee, Category “Space”
  • 2010: Space Foundation
    Space Foundation
    The Space Foundation is a nonprofit organization that supports the global space industry through information and education programs. It is a resource for the entire space community - industry, national security organizations, civil space agencies, private space companies and the military around the...

     “John L. 'Jack' Swigert Jr., Award for Space Exploration”
  • 2010: National Space Society “Space Pioneer Award” 2009, Category “Science and Engineering”
  • 2010: Northrop Grumman
    Northrop Grumman
    Northrop Grumman Corporation is an American global aerospace and defense technology company formed by the 1994 purchase of Grumman by Northrop. The company was the fourth-largest defense contractor in the world as of 2010, and the largest builder of naval vessels. Northrop Grumman employs over...

     “Distinguished Engineering Project Achievement Award”, 55th Annual Engineering Council
  • 2010: NASA
    NASA
    The National Aeronautics and Space Administration is the agency of the United States government that is responsible for the nation's civilian space program and for aeronautics and aerospace research...

     OCE Systems Engineering Award, NASA Office of Chief Engineer
  • 2010: Aviation Week 2009 Program Excellence Award, Category “System Level Production & Sustainment”
  • 2009: Northrop Grumman
    Northrop Grumman
    Northrop Grumman Corporation is an American global aerospace and defense technology company formed by the 1994 purchase of Grumman by Northrop. The company was the fourth-largest defense contractor in the world as of 2010, and the largest builder of naval vessels. Northrop Grumman employs over...

     Technical Services’ “Award for Excellence”: 2009, (LCROSS team)
  • 2009: NASA
    NASA
    The National Aeronautics and Space Administration is the agency of the United States government that is responsible for the nation's civilian space program and for aeronautics and aerospace research...

     Ames Honor Award, category “team” (LCROSS Team)
  • 2009: NASA
    NASA
    The National Aeronautics and Space Administration is the agency of the United States government that is responsible for the nation's civilian space program and for aeronautics and aerospace research...

     Ames Honor Award, category “Engineering” (Tom Luzod)
  • 2009: NASA
    NASA
    The National Aeronautics and Space Administration is the agency of the United States government that is responsible for the nation's civilian space program and for aeronautics and aerospace research...

     Honor Award - Exceptional Achievement Medal, (Dan Andrews)
  • 2009: NASA
    NASA
    The National Aeronautics and Space Administration is the agency of the United States government that is responsible for the nation's civilian space program and for aeronautics and aerospace research...

     Honor Award - Group Achievement, LCROSS Project Team
  • 2008: ILEWG International Lunar Exploration “Technology Award”, for the development of advanced technologies within hard constraints of short time and cost
  • 2008: NASA
    NASA
    The National Aeronautics and Space Administration is the agency of the United States government that is responsible for the nation's civilian space program and for aeronautics and aerospace research...

     Ames Honor Award, category “Engineering” (Bob Barber)
  • 2008: Northrop Grumman
    Northrop Grumman
    Northrop Grumman Corporation is an American global aerospace and defense technology company formed by the 1994 purchase of Grumman by Northrop. The company was the fourth-largest defense contractor in the world as of 2010, and the largest builder of naval vessels. Northrop Grumman employs over...

     “Mission Excellence” Award, LCROSS Spacecraft Team
  • 2007: NASA
    NASA
    The National Aeronautics and Space Administration is the agency of the United States government that is responsible for the nation's civilian space program and for aeronautics and aerospace research...

     Ames Honor Award - Group Achievement, Successful completion of CDR
  • 2006: NASA
    NASA
    The National Aeronautics and Space Administration is the agency of the United States government that is responsible for the nation's civilian space program and for aeronautics and aerospace research...

    Ames Honor Award, category “Project Management” (Dan Andrews)

External resources

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