Image: NASA / GSFC / Arizona State University
SLIM (Smart Lander for Investigating Moon)
Mission Profile
| Launch date | 2023-09-06 |
|---|---|
| Launch site | Tanegashima Space Center, Yoshinobu Launch Complex LP-1, Japan |
| Launch vehicle | H-IIA F47 (co-manifested with XRISM) |
| Spacecraft | SLIM — 200-kg-class lander with image-based pinpoint navigation |
| Target | Moon |
| Type | Robotic |
| End date | 2024-08-23 |
| Recovery | Permanent on lunar surface — near Shioli crater, Mare Nectaris |
| Landing site | 13.3°S, 25.2°E (eastern flank of Shioli crater, Mare Nectaris near side) |
| Surface stay | 216 days of intermittent operations across three lunar day/night cycles |
| Mass | ~730 kg wet; ~200 kg dry |
| Duration | 216 days of intermittent operations across 3 lunar day/night cycles |
| Partners | JAXA/ISAS (lead), Mitsubishi Electric (bus), Tomy + Sony Group (SORA-Q), Doshisha University (LEV-2) |
| Instruments | Multi-Band Camera (MBC), Laser Range Finder, LEV-1 hopping rover, LEV-2 / SORA-Q transformable rover |
Overview
SLIM — the Smart Lander for Investigating Moon, nicknamed "Moon Sniper" — achieved the world's first sub-100-meter pinpoint lunar landing on 19 January 2024, touching down within approximately 55 meters of its target near Shioli crater on the eastern flank of Mare Nectaris. The 730-kg, 200-kg-class lander, built by JAXA's Institute of Space and Astronautical Science (ISAS), demonstrated image-based real-time crater-matching navigation that compared descent-camera images against an onboard terrain map. Unfortunately, a main-engine nozzle anomaly during terminal descent left SLIM in a nose-down attitude after touchdown, with its solar arrays pointed in the wrong direction. JAXA waited nine days for the Sun angle to shift; on 28 January, the arrays produced power and the Multi-Band Camera began returning spectroscopy of nearby olivine boulders — proxies for lunar mantle composition. SLIM was not thermally designed for lunar nights, but it surprised JAXA by surviving the first night, then the second, and finally the third before operations were formally concluded on 23 August 2024. The mission also deployed two micro-rovers: the 2.1-kg hopping LEV-1 and the 250-gram transformable LEV-2 (SORA-Q), the smallest and lightest robotic rover ever flown on the Moon. SLIM made Japan the fifth nation to soft-land on the lunar surface.
Mission Objectives
Demonstrate pinpoint landing accuracy within 100 m of the target
achieved
Validate image-based crater-matching navigation during lunar descent
achieved
Deploy LEV-1 and LEV-2 (SORA-Q) micro-rovers
achieved
Conduct Multi-Band Camera spectroscopy of olivine/mantle materials
partial
Survive at least one lunar day
achieved
Vehicle Specifications
Spacecraft (wet mass)
- Mass
- ~730 kg
JAXA spec at launch.
Spacecraft (dry mass)
- Mass
- ~200 kg
200-kg class — designed for minimum-mass precision landing.
Main propulsion
Two 500 N bipropellant (N2H4 / MON-3) main engines.
Bus dimensions
- Dimensions
- 2.7 × 1.7 × 2.4 m stowed
Two-stage landing geometry with sacrificial nozzle.
LEV-1 hopper
- Mass
- 2.1 kg
Hopping micro-rover; deployed pre-touchdown.
LEV-2 / SORA-Q
- Mass
- 0.25 kg
Transformable ball developed with Tomy and Sony — smallest lunar rover ever flown.
Multi-Band Camera (MBC)
10-band imaging spectrometer covering 0.65–1.7 μm for olivine composition.
Key Milestones
2023-09-06
Launch on H-IIA F47 from Tanegashima at 23:42 UTC (co-manifested with XRISM)
2023-12-25
Lunar orbit insertion
2024-01-19
Powered descent initiation at 15:00 UTC
2024-01-19
Touchdown near Shioli crater at 15:20 UTC — nose-down orientation
2024-01-19
LEV-1 and SORA-Q deployed prior to touchdown
2024-01-28
Solar power restored as Sun angle shifted; MBC science operations begin
2024-04-23
SLIM survives second lunar night unexpectedly
2024-08-23
JAXA formally concludes operations after third-night survival
Key Achievements
World's first sub-100-meter pinpoint lunar landing (~55 m error)
First Japanese soft landing on the Moon — Japan becomes 5th nation overall
First image-based real-time crater-matching navigation demonstrated on lunar descent
Smallest and lightest robotic lunar rover ever flown (LEV-2 / SORA-Q at 250 g)
Survived three lunar nights despite no thermal design for nighttime operations
First in-situ multi-band spectroscopy of olivine boulders near Shioli crater (mantle composition proxy)
Photo Gallery
Legacy & Significance
SLIM's "Moon Sniper" thesis — that future landers should be measured in meters, not kilometers — reframed the entire lander-design problem. Apollo aimed for 20-km ellipses; Chang'e 5 for ~7 km; SLIM proved 55 m on the first try. That precision is the prerequisite for Artemis south-pole science, where useful ice deposits sit inside specific permanently shadowed craters. JAXA's vision-based navigation stack (terrain-matching plus descent-camera SLAM) is now the reference architecture cited by NASA CLPS, ESA Argonaut, and ISRO Chandrayaan-4. SLIM's accidental three-lunar-night survival also embarrassed the conservative thermal-design orthodoxy that had insisted nighttime survival required radioisotope heaters. Domestically, SLIM rescued JAXA's lunar credibility after the OMOTENASHI and Hakuto-R losses of 2022 – 23 and unlocked political support for the LUPEX rover (joint with ISRO) and Japan's Artemis Gateway HALO contribution.
