Laser Retroreflector Array (LRA)¶
IM-6 · manifested · NASA payload
A passive optical marker: eight small quartz corner-cube prisms in a dome-shaped aluminum frame. Laser altimeters on orbiters or approaching landers can range to it from most directions, so it marks the lander's position for decades and helps orbiters fix their own orbits. It needs no power.
PI: Xiaoli Sun (NASA Goddard), PI of the LRA project; deputy PI Daniel Cremons. NASA's 2026 releases name no PI for these units.
Built by: NASA Goddard Space Flight Center (NASA center)
| Technology | passive navigation marker (laser retroreflector) |
| Moon Base need | #0101, #1101 (The study's reading. No NASA gap names the LRA; the knowledge base's own matching for the four late-2028 landings lists the LRA with no data gap ('navigation aid'). NASA flies the LRA on all four of those landings to 'build out a global network of ... location markers', which fits #0101 (surface positioning) and #1101 (precision landing). IM-6's site is not in the sources. A late-2028 landing falls in Phase 1 ('Now through 2028'), the study's reading.) |
| Route onto CLPS | other NASA; No payload call. The LRA is a CLPS-program payload that goes on most CLPS landers. NASA's Moon Base Program named the same three 'flight-proven' payloads (SCALPSS, LRA, LETS) for each of four late-2028 landings, awarded on 30 June 2026; Intuitive Machines' share is IM-6 ($148.3 million). Voyager names the procurement CS-8; that IM-6 is a CS-8 order is the study's reading.; 2026-06-30 |
| Timeline | first funding not in public sources (the design was space-qualified at Goddard in 2018); first flight test 2019-02-21 (the design, on Beresheet); selected 2026-06-30 (named for the four late-2028 landings); launch no earlier than Q4 2028 (SCALPSS team poster); Intuitive Machines: lander to the Moon no later than 2028; landing late 2028 (NASA, target) |
| On the Moon | not yet flown |
| FO | none |
Flights before the Moon¶
- earlier lunar mission: SpaceIL's Beresheet lander (the same Goddard design, metal-coated), 2019-02-21 (launch). The first flight of the design: integrated in November 2018, the first NASA instrument on a non-governmental mission to the Moon. How Beresheet ended is not in these sources.
"LRALL was integrated with the SpaceIL Beresheet spacecraft prior to its February 21, 2019 launch and became the first NASA instrument to fly on a non-governmental mission to the Moon"
— NTRS 20205001993
- earlier lunar mission: ISRO's Chandrayaan-2 Vikram lander (an uncoated version), 2019. A space-qualified uncoated version, integrated in April 2019. The landing attempt is not described in these sources.
"one of which was integrated in April, 2019 with the Indian Space Research Organization (ISRO) Vikram lander, a part of the Chandrayaan-2 mission"
— NTRS 20205001993
- earlier lunar mission: ISRO's Chandrayaan-3 Vikram lander (NASA LRA), 2023-08-23 (landing). The design on the surface, working. LRO's laser altimeter has ranged to it since 12 December 2023; by December 2025 the success rate was 32% by day and 9% by night.
"ISRO's (Indian Space Research Organization) Vikram lander, with a NASA retroreflector on it, touched down on the Moon on Aug. 23, 2023."
— Laser Instrument on NASA’s LRO Successfully ‘Pings’ Indian Moon Lander - NASA Science"32% daytime and 9% nighttime for CH3"
— hou.usra.edu: 1707.pdf
- earlier lunar mission: JAXA's SLIM lander (a NASA retroreflector), 2024-01-19 (landing). A NASA LRA on the surface. LRO ranged to it, though rarely, because SLIM rests in an off-nominal attitude.
"including one on JAXA's (Japan Aerospace Exploration Agency) SLIM lander, due to land on the Moon on Jan. 19, 2024"
— Laser Instrument on NASA’s LRO Successfully ‘Pings’ Indian Moon Lander - NASA Science"The number of opportunities and success rate to SLIM were low given the off-nominal lander attitude."
— hou.usra.edu: 1707.pdf
- Earth orbit or deep space: Astrobotic's Peregrine Mission One (its NASA LRA), 2024-01-08 (launch); did not land. Nothing: the LRA is passive and works only on the surface, and Peregrine did not land.
"As NASA’s LRA (Laser Retroreflector Array) instrument is a passive experiment, and operations could only take place on the lunar surface."
— NASA Science, Astrobotic Peregrine Mission One Concludes - NASA
- earlier lunar mission: Intuitive Machines' IM-1 (Nova-C 'Odysseus'), 2024-02-22 (landing). The design on an Intuitive Machines lander. Odysseus tipped over and its LRA sits on a solar panel facing almost to the horizon; LRO had no returns from it as of December 2025.
"So far, no returns have been received from IM-1, but this is not surprising given its off-nominal landing and the location of the LRA on a solar panel"
— hou.usra.edu: 1707.pdf
- earlier lunar mission: Intuitive Machines' IM-2 (Nova-C 'Athena') at Mons Mouton, 2025-03-06 (landing). The design near the South Pole on a Nova-C. Athena landed on its side; the array stays fixed to its top deck. No ranging to it is reported in these sources (LRO's late-2025 list of landed mini-LRAs leaves it out).
"will remain affixed to the top deck of the lander"
— NASA Receives Some Data Before Intuitive Machines Ends Lunar Mission - NASA"As of late 2025 these include the Chandrayaan-3 (CH3) lander"
— hou.usra.edu: 1707.pdf, list: CH3, IM-1, SLIM, CE6
Heritage hardware¶
- design heritage and batch build: Eight 1.27 cm fused-silica corner cubes in a 5 cm aluminum dome, about 20 g, designed and tested for decades on the surface, including radiation to 19 Mrad. Space-qualified at Goddard in 2018. Similar small arrays flew on the ExoMars and InSight Mars landers. Goddard had optically tested 13 units by 2021; which unit flies on this lander is not stated.
"These devices consist of a small aluminum hemisphere, 2 inches (5 centimeters) in diameter and 0.7 ounces (20 grams) in weight"
— How NASA Uses Simple Technology to Track Lunar Missions - NASA"including radiation testing to 19 Mrad (Si)"
— NTRS 20210010915, LPSC 2021 poster"All 13 LRALL units tested met the design specification"
— NTRS 20210010915, LPSC 2021 poster"Similar small LRAs were placed on the ExoMars and InSight landers"
— NTRS 20205001993
Funding before the lunar flight¶
- NASA's CLPS program, which developed the LRA design (with a NASA Postdoctoral Program fellowship for the optical tests). No amount public for the program or for one unit; no SBIR or USAspending award names these arrays (see open questions). (NASA CLPS; from about 2018): amount not in public sources
"Funding National Aeronautics and Space Administration (NASA) Commercial Lunar Payload Services (CLPS)"
— NTRS 20205001993, Funding"Laser Retroreflector Arrays for Lunar Landers (LRALL) developed under the Commercial Lunar Payload Services (CLPS) program"
— NTRS 20210010915, LPSC 2021 poster
How it got onto CLPS¶
"Laser Retroreflector Arrays for Lunar Landers (LRALL) developed under the Commercial Lunar Payload Services (CLPS) program"
— NTRS 20210010915, LPSC 2021 poster"Each delivery will carry three NASA payloads to the lunar surface:"
— NASA Awards More Moon Base Science, Previews New Opportunities - NASA"These three payloads are flight-proven and their data is critical to supporting safe human exploration of the lunar surface."
— NASA Awards More Moon Base Science, Previews New Opportunities - NASA"a laser retroreflector array (LRA) for precise cislunar positioning"
— Intuitive Machines wins NASA CLPS contract up to $148.3M, Intuitive Machines, 30 Jun 2026"including the CS-8 competitive procurement under the existing Commercial Lunar Payload Services (CLPS) indefinite delivery/indefinite-quantity framework"
— Voyager Awarded $298M NASA Contract Under Completed Astrobotic Acquisition
On the Moon¶
Manifested on IM-6, a production Nova-C, for late 2028; the site is not in the sources. NASA has LRAs manifested on several other landers (IM-4, IM-5, Blue Moon Pathfinder Mission 1, Blue Ghost Mission 4 and the other three late-2028 landings), some of which may land first.
"Reflects laser beams transmitted by Moon orbiters or landing spacecraft to help them determine their orbit position or navigate to the surface."
— NASA Awards More Moon Base Science, Previews New Opportunities - NASA
FO's role¶
Grade: none. No FO project, flight or report mentions the LRA or its Goddard team. A passive marker had no need of a suborbital test; its proof came from earlier landers and LRO ranging. The study's earlier traceback grade for every earlier LRA (none found) applies.
"No FO record or report names SCALPSS, ROLSES, LN-1, the retroreflectors,"
— earlier finding of this study (not a public source)"Nothing in the FO sources (a passive reflector)."
— earlier finding of this study (not a public source)
Who built it¶
"Dr. Xiaoli Sun, also of NASA Goddard and principal investigator for the LRA project"
— How NASA Uses Simple Technology to Track Lunar Missions - NASA, Feb 2024"deputy principal investigator for the"
— How NASA Uses Simple Technology to Track Lunar Missions - NASA, Daniel Cremons
Moon Base need¶
"These arrays have flown on previous CLPS landers and international lunar landers and will continue to be used to build a network of permanent location markers on the Moon for future exploration."
— NASA Awards More Moon Base Science, Previews New Opportunities - NASA"build out a global network of environmental data and location markers on the Moon"
— NASA Awards More Moon Base Science, Previews New Opportunities - NASA"Navigation aid, not a data gap's subject."
— Moon to Mars knowledge base: Architecture data gaps: all 25, June 2026 landings table, LRA row"LRAs can eventually be used to help spacecraft land in otherwise pitch-dark places close to permanently shadowed regions near the lunar South Pole"
— How NASA Uses Simple Technology to Track Lunar Missions - NASA"Phase 1 "Now through 2028""
— Moon to Mars knowledge base: Moon Base phases
Open questions¶
- Which tested LRA unit flies on IM-6: not in public sources.
- The LRA program's cost and the cost per array: not in public sources. A June 2024 Goddard purchase, 'Precision optical laser retroreflector array' from Sellers Optical (80NSSC24PB542, $58,890, performed in Greenbelt), may be LRA hardware; the record does not say.
- IM-6's landing site, and where the LRA will be mounted on the production Nova-C: not in public sources.