NASA Logo, National Aeronautics and Space Administration
NASA Space Science Data Coordinated Archive Header

Lunar Reconnaissance Orbiter (LRO)



The Lunar Reconnaissance Orbiter (LRO), the first mission of NASA's Robotic Lunar Exploration Program, is designed to map the surface of the Moon and characterize future landing sites in terms of terrain roughness, usable resources, and radiation environment with the ultimate goal of facilitating the return of humans to the Moon. The following measurements have the highest priority: characterization of deep space radiation environment in lunar orbit; geodetic global topography; high spatial resolution hydrogen mapping; temperature mapping in polar shadowed regions; imaging of surface in permanently shadowed regions; identification of putative deposits of appreciable near-surface water ice in polar cold traps; assessment of meter and smaller scale features for landing sites; and characterization of polar region lighting environment. A primary goal of the mission is to find landing sites suitable for in situ resource utilization (ISRU).

LRO launched along with its companion spacecraft, the Lunar Crater Observation and Sensing Satellite (LCROSS), from Kennedy Space Center on 18 June 2009 on an Atlas 5 401 launch vehicle at 21:32 UT (5:32 p.m. EDT). LRO and LCROSS separated at 22:16:43 UT. LRO was put into a direct insertion trajectory and reached the Moon on 23 June at 09:43 UT (5:43 a.m. EDT). It entered an initial 5 hour orbit with a periselene altitude of roughly 100 km which was lowered into a 50 km circular orbit. The mission spent one year in a 30 - 70 km altitude lunar polar orbit, called the exploration phase of the mission. In September 2010 it started the science phase, where it was put into a quasi-stable, low-maintenance ~30 x 180 km orbit. As of September 2015 it was in its second extended science mission. The satellite had a launch mass of about 1846 kg, and a dry mass of less than 949 kg. The platform is three-axis stabilized and power of about 1850 W (end-of-life), giving 800 W average over each orbit, will be provided by a 10.7 square meter solar array and stored in an 80 A-hr Li-ion battery. Communications are via S-band for uplink and low rate downlink and Ka-band for high rate downlink (100-300 Mbps). The spacecraft carries 92 kg of scientific payload composed of: Lunar Reconnaissance Orbiter Camera (LROC), two narrow-angle (1 m resolution) monochromatic cameras and one wide-angle (100 m resolution) color and UV camera to acquire images of small scale landing site hazards and document lighting conditions at the lunar poles; Lunar Orbiter Laser Altimeter (LOLA), a laser altimeter to measure landing site slopes and search for polar ices; Lunar Exploration Neutron Detector (LEND), a neutron detector to search for water ice and characterize the space radiation environment; Diviner Lunar Radiometer Experiment (DLRE), a radiometer to map the temperature of the lunar surface to identify cold traps and possible lunar ice deposits; Lyman-Alpha Mapping Project (LAMP), a Lyman-alpha mapper to observe the lunar surface in the far ultraviolet, looking for surface ices and frosts and imaging permanently shadowed regions; and Cosmic Ray Telescope for the Effects of Radiation (CRaTER), a device to investigate background space radiation using tissue-equivalent plastics. NASA has also signed an agreement with the U.S. National Reconnaissance Office to cooperate on the development of Mini-RF, a miniature synthetic aperture radar sensor to map the Moon's surface. Total payload power requirement is about 125 W. The total estimated total cost for the mission is roughly $460 million.


The Lunar Crater Observation and Sensing Satellite (LCROSS) was launched along with the LRO spacecraft. LCROSS is designed to search for water ice on the Moon's surface. The mission consists of a Shepherding Spacecraft (S-S/C) attached to the Centaur upper stage. The S-S/C guided the Centaur after orbital insertion through two highly eccentric 40 day earth orbits. The S-S/C then guided the Centaur into a trajectory to impact Cabeus, a permanently shadowed site on the Moon, chosen for its likelihood of containing water ice. The S-S/C separated from the Centaur and performed a delay burn to follow ten minutes behind. The Centaur impacted the lunar surface at 11:31 UT on 9 October 2009, throwing up a cloud of debris. The S-S/C took images and collected other data on the impact and cloud of ejecta before also striking the Moon at 11:36 UT. The S-S/C was built on an EELV Secondary Payload Adaptor (ESPA) ring with a dry mass of approximately 534 kg and 300 kg of hydrazine propellant. Power is supplied by a 420 W solar array charging a 40 A-h Li-Ion battery. Propulsion is through two 8-thruster pods and communications will be via two omnidirectional and two horn antennas. The S-S/C was equipped with two visible cameras, three infrared cameras, three spectrometers, and a photometer for observations.

Alternate Names

  • 35315
  • LRO
  • LRO
  • urn:nasa:pds:context:instrument_host:spacecraft.lro

Facts in Brief

Launch Date: 2009-06-18
Launch Vehicle: Atlas V 401
Launch Site: Cape Canaveral, United States
Mass: 500 kg

Funding Agency

  • National Aeronautics and Space Administration (United States)


  • Planetary Science

Additional Information

Questions and comments about this spacecraft can be directed to: Dr. David R. Williams



NameRoleOriginal AffiliationE-mail
Dr. Craig R. TooleyProject ManagerNASA Goddard Space Flight
Dr. Noah PetroProject ScientistNASA Goddard Space Flight

Selected References

  • Chin, G., et al., Lunar Reconnaissance Orbiter Overview: The Instrument Suite and Mission, Space Sci. Rev., 129, 391-419, doi:10.1007/s11214-007-9153-y, 2007.
  • Tooley, C. R., et al., Lunar Reconnaissance Orbiter Mission and Spacecraft Design, Space Sci. Rev., 150, 23-62, doi:10.1007/s11214-009-9624-4, 2010.
  • Vondrak, R., et al., Lunar Reconnaissance Orbiter (LRO): Observations for Lunar Exploration and Science, Space Sci. Rev., 150, 7-22, doi:10.1007/s11214-010-9631-5, 2010.
[LRO Science Payload]

Lunar Crater Observation and Sensing Satellite (LCROSS)

Lunar Reconnaissance Orbiter Home Page - Goddard Space Flight Center

NASA's LRO spacecraft sends first lunar images to Earth - 2 July 2009 NASA Press Release
NASA Returning to the Moon with First Lunar Launch in a Decade - 18 June 2009 NASA Press Release
NASA's next Moon mission begins thermal vacuum test - 23 October 2008 NASA Press Release
NASA set to launch LRO in 2008 - 18 May 2006 NASA Press Release
Instruments selected for LRO - 22 December 2004 NASA Press Release

Moon Page
Moon Fact Sheet

[] NASA Logo -