MoonLIGHT Pointing Actuator (MPAc), ESA¶
IM-3 · manifested · partner payload
A single large (100 mm) laser retroreflector, MoonLIGHT, on a robotic two-axis actuator (MPAc) that points it at Earth after landing, with a removable dust cover. Laser stations in the US, Italy and France will range to it, to test general relativity and study the Moon's interior and the Earth-Moon distance.
PI: Marco Muccino (INFN-LNF)
Built by: INFN-LNF (Italy's National Institute for Nuclear Physics, Frascati National Laboratories), for ESA; the MoonLIGHT reflector was designed with the University of Maryland (partner agency)
| Technology | laser retroreflector with pointing actuator (lunar laser ranging) |
| Moon Base need | #0101 (The study's reading, and a weak fit. MoonLIGHT's aims are fundamental physics and the lunar interior. Its team says next-generation reflectors may also serve as control points for lunar reference systems and for navigation from orbiters with laser ranging, which bears on tech gap #0101 (surface positioning, navigation and timing) only indirectly. No data gap covers it. NASA's Moon Base page puts IM-3 in Phase One.) |
| Route onto CLPS | partner; INFN proposed MPAc to ESA in 2018. In 2019 ESA chose it among 135 eligible proposals and contracted INFN-LNF (ESA contract 4000129000/19/NL/TFD). In 2021 ESA agreed with NASA, under a NASA-ESA memorandum for CP-11, to fly it on the first PRISM delivery to Reiner Gamma; the CLPS task-order request included MPAc's accommodation.; 2021 |
| Timeline | first funding 2019 (ESA contract and ASI agreement); first flight test not in public sources; selected 2019 by ESA; 2021 agreed with NASA for CP-11; launch no earlier than the first part of 2027 (NASA, September 2026, per Wikipedia). The hardware was qualified and has been in storage since December 2023.; landing not in public sources |
| On the Moon | not yet flown |
| FO | none |
Flights before the Moon¶
- earlier lunar mission: Firefly's Blue Ghost Mission 1, carrying NGLR-1, the University of Maryland's reflector of the same optical design (not MPAc, and not built by INFN), 2025-03-02. The shared 100 mm single-reflector design on the Moon: Earth stations ranged to NGLR-1 from March 2025 (see bgm1-nglr). It had fixed pointing and no actuator or dust cover, so MPAc's own mechanisms have not flown. Goddard's LRO laser altimeter also ranges to NGLR-1 as practice for large reflectors such as MoonLIGHT. A shared design by a partly different team: it counts in the broad count only, as in the study's earlier feeder-line map.
"shares its design with the Next Generation Laser Retroreflector NGLR from UMD"
— CP-11 Science Payloads - NASA Science"NGLR-1 was deployed on the 2nd of March."
— NGLR: Next Generation Lunar Retroreflector, University of Maryland Physics; text extracted from t…, UMD NGLR page"The first NGLR (with fixed pointing) will be launched with a NASA-CLPS mission"
— NTRS 20210025424"serves as an exercise range to future large cubes to be"
— hou.usra.edu: 1707.pdf, (LRO's laser altimeter ranging to Apollo 15 and BG-1; continues: 'deployed on the Moon by the CLPS landers (such as MoonLIGHT in 2026)')
Heritage hardware¶
- design heritage: MoonLIGHT and NGLR share an optics design inherited from the Apollo retroreflector arrays, scaled up from many small cubes to one 100 mm cube so that lunar librations do not spread the return pulse. Earth-based prototypes of MPAc were built before the proto-flight model.
"These instruments share a common optics design [1], inherited from Apollo LRAs"
— NTRS 20210025424"Moving from a multi small CCRs array to a single large 100 mm CCR, called MoonLIGHT, unaffected by the lunar librations."
— Abstract EGU23-15759"Terrestrial prototypes, with all the characteristics of the final structure, have been developed"
— Abstract EGU23-15759
Funding before the lunar flight¶
- ESA contract to INFN-LNF for MPAc (4000129000/19/NL/TFD), and an Italian Space Agency agreement (2019-15-HH.0) for the MoonLIGHT reflector. Amounts not public. Foreign funding: no SBIR or USAspending record applies. NASA pays only the delivery, inside the CP-11 task order. (ESA; ASI; 2019 on): amount not in public sources
"Work by INFN-LNF authors is supported by ESA under Contract n. 4000129000/19/NL/TFD"
— NTRS 20210025424, acknowledgements"by ASI under Agreement n. 2019-15-HH.0"
— NTRS 20210025424, acknowledgements"Moon Laser Instrumentation for General relativity/geophysics High-accuracy Tests (MoonLIGHT) by INFN, funded by ESA and ASI"
— NTRS 20210025424, footnote 1
How it got onto CLPS¶
"In 2018 INFN proposed to ESA the MoonLIGHT Pointing Actuators (MPAc) project"
— Abstract EGU23-15759"In 2019 ESA chose MPAc among 135 eligible scientific project proposals."
— Abstract EGU23-15759"In 2021 ESA agreed with NASA to launch MPAc to the Reiner Gamma region of the Moon"
— Abstract EGU23-15759"supported by ESA under Contract n. 4000129000/19/NL/TFD (and a NASA-ESA MoU for CP-11)"
— NTRS 20210025424, acknowledgements"MoonLIGHT is managed by the European Space Agency (ESA)."
— NASA Selects Intuitive Machines for New Lunar Science Delivery - NASA
On the Moon¶
Waiting for IM-3. The reflector is passive and long-lived; the actuator must point it once after landing.
"ESA's MoonLIGHT Pointing Actuator (MPAc)"
— CP-11 Science Payloads - NASA Science
FO's role¶
Grade: none. No FO project, flight or report names MoonLIGHT, MPAc, INFN or any retroreflector. It is a European partner payload; FO's calls are for US entities, so none was expected. The design's flight proof came from NGLR on the Moon, not from suborbital tests. The study's earlier traceback grade (none found) stands.
"International partner payload delivered under NASA's CLPS order. Nothing in the FO sources."
— earlier finding of this study (not a public source)"No FO record or report names SCALPSS, ROLSES, LN-1, the retroreflectors,"
— earlier finding of this study (not a public source)
Who built it¶
"Lead Development Organization: ESA"
— CP-11 Science Payloads - NASA Science"Payload PI: Marco Muccino"
— CP-11 Science Payloads - NASA Science"a laser retroreflector developed by the National Institute for Nuclear Physics"
— ntrs.nasa.gov: CLPS2025LPSCv1.pdf"MoonLIGHT project is designed by SCF_Lab joined UMD"
— Abstract EGU23-15759
Moon Base need¶
"Key Measurement: Measure the size, shape, and liquid core of the Moon. Also, a target to measure Earth-Moon distance."
— CP-11 Science Payloads - NASA Science"ay serve as control points for lunar reference systems"
— NTRS 20210025424, white paper, 2021"Absolute and relative positioning, navigation and timing (PNT) for crew and surface assets"
— Moon to Mars knowledge base: ESDMD #0101: Positioning, Navigation, and Timing for Lunar Surface Extreme Environments"planned for Phase One of Moon Base development"
— Moon Base Phases - NASA, IM-3 listed below
Open questions¶
- ESA's and ASI's spending on MoonLIGHT and MPAc: not in public sources.
- Muccino et al. 2025 (Remote Sensing 17(5):813) describes the qualified hardware in full; the publisher blocked the download here, so it was not read.
- Has the actuator or dust cover been tested in reduced gravity or in a dusty landing environment? Not in the sources read.
- How long the stored hardware (since December 2023) can wait before retest: not in public sources.