Laser Retroreflector Array (LRA)¶
IM-5 · 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, as for the earlier LRAs. No NASA gap names the LRA; the knowledge base files it as a navigation aid, not a data gap's subject. NASA says LRAs build 'a network of permanent location markers' and could guide landings in the dark near the South Pole; that fits #0101 (surface positioning) and #1101 (precision landing). IM-5's site, Mons Malapert near the South Pole, would add a polar marker. A 2030 landing falls in Phase 2 by date, the study's reading.) |
| Route onto CLPS | other NASA; No payload call. The LRA was developed under NASA's CLPS program itself and goes on most CLPS landers. In 2020 NASA put an LRA on Masten Mission One (TO 19C) alongside NIRVSS and MSolo; that order was cancelled and its payloads were to be re-manifested. NASA named an LRA among IM-5's payloads in March 2026 (CT-4). Whether this is the unit built for Masten is not stated; IM-5 carries three of Masten's NASA payloads (NIRVSS, MSolo, LRA), so the study reads it as possible.; 2026-03-24 |
| 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 2020-04-08 (an LRA on Masten Mission One, cancelled); 2026-03-24 (named in the CT-4 award); launch not in public sources (landing targeted for 2030); landing 2030 (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"LRALL units are manifested on upcoming CLPS missions, including Peregrine Mission 1 (Astorbotic), IM-1 (Intuitive Machines), and Masten Mission 1 (Masten Space)."
— NTRS 20210010915, LPSC 2021 poster"Laser Retroreflector Array (LRA) is a series of eight small mirrors to measure distance and support landing accuracy."
— NASA Awards Contract to Deliver Science, Tech to Moon Ahead of Human Missions - NASA, Masten award, 8 Apr 2020"TO 19C: Awarded to Masten Space Systems; the payloads are now being re-manifested on other TOs."
— ntrs.nasa.gov: CLPS2025LPSCv1.pdf"NASA’s Laser Retroreflector Array (LRA) is a small device that reflects laser beams transmitted by Moon orbiters or landing spacecraft"
— NASA Selects Intuitive Machines to Deliver Artemis Science, Tech to Moon - NASA, 27 Mar 2026
On the Moon¶
Manifested on IM-5 (Nova-D), targeted for 2030 at Mons Malapert. NASA's March 2026 release says one LRA has already been delivered to the surface through CLPS; IM-1 and IM-2 each landed one, both on tipped landers, so 'one' may count only a working array or may be an error. Not resolved.
"One LRA payload has already been delivered through CLPS to the surface of the Moon."
— NASA Selects Intuitive Machines to Deliver Artemis Science, Tech to Moon - 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. One lesson from the tipped IM-1 array (mounted on a solar panel that now faces the horizon) is about mounting, not about flight testing.
"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¶
"Lead development organization: NASA’s Goddard Space Flight Center"
— NASA Selects Intuitive Machines to Deliver Artemis Science, Tech to Moon - NASA"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 will continue to be used to build a network of permanent location markers on the Moon for future exploration."
— NASA Selects Intuitive Machines to Deliver Artemis Science, Tech to Moon - NASA"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"Navigation aid, not a data gap's subject."
— Moon to Mars knowledge base: Architecture data gaps: all 25, June 2026 landings table, LRA row
Open questions¶
- Is the IM-5 LRA the unit built for Masten Mission One? 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.
- Why does NASA's March 2026 release say only one LRA has been delivered through CLPS, when IM-1 and IM-2 each landed one?
- Where will the LRA be mounted on Nova-D, after the tipped IM-1 and IM-2 arrays? Not in public sources.