Smart Lander for Investigating
Moon (SLIM)
Results from the Moon Landing

Institute of Space andAstronautical Science
SLIM Project Team
Project Manager
Sakai Shin-ichiroToday’s report
Today, we are pleased to report on the results from the Smart
Lander for Investigating Moon (SLIM) moon landing descentoperation, that was conducted on 01/19 ~ 01/20, 2024.

1. Introduction on SLIM project
2. Actual landing descent progress (to an altitude of about 50m)
3. Results from image matching and evaluation of the pinpoint
landing accuracy
4. Situation arising at an altitude of approximately 50m
5. Estimation of spacecraft behaviour after an abnormal
occurrence
6. Post-landing spacecraft operations, and images obtained withthe multi-band spectroscopic camera
7. Summary2

Mission Objectives of SLIM
SLIM （Smart Lander for Investigating Moon） is a JAXA project aiming
to contribute to future lunar and planetary exploration by achieving
the following two objectives.

Objective A

Demonstration of high-precision landing technology
on the moon•

Aimed landing accuracy of 100m compared to several kilometers to tens ofkilometers of conventional lunar landers.

•

Key technology includes “Vision-based navigation" and “Navigation, guidance andcontrol"

Objective B

Realization of a lightweight lunar and planetary probe
system to allow more frequent lunar and planetary
exploration missions•

Small, lightweight, and high-performance chemical propulsion system•

Weight reduction of core elements in most spacecrafts such as computers andpower supply systems
3

SLIM Configuration• Mass： 200kg（Dry） / 700-730kg（Wet）• Size: 2.4m x 1.7m x 2.7m
S-band antennaThin film solar cell

Rocket connecting
ring

Tank

Navigation
Camera(CAM-MZ)

Navigation
Camera(CAM-PX)
Small prove(LEV)

Landing radar

22N-Thruster (12 unit)
Main engine (2unit)
Shock absorber(Contact points to Lunar surface)

SLIM has adopted a fuel and oxidizer integrated tank to reduce weight. Thiscylindrical tank is also used as the structure base.
4Outline of landing sequence
1. Initiate the landing descent from lunar orbit and approach the target site on the lunar surface
through autonomous navigation and guidance control, while precisely estimating the current
position using image-based navigation with the navigation cameras.
2. From above the target site, precise measurement of altitude and terrain-relative velocity conductedusing the landing radar that is integrated into the navigation guidance system.
3. Image-based obstacle detection is performed at approximately 50m above the landing site andlanding is performed autonomously, avoiding hazardous boulders and other obstacles. That is,
pinpoint landing is prioritised up to 50m above the surface, after which obstacle avoidance isprioritised for landing safety.
[Note] Spacecraft position and velocity are propagated by the onboard accelerometers and corrected
to higher accuracy by image-based navigation. Additionally, the navigation camera images are also
taken at regular intervals for use in the post-landing analysis, even when image navigation is not being
performed.

Powered動力降下
descent

Pre-landing lunar orbit.
Elliptical orbit with dimensions
approximately 15 x 600km

Altitude 15km
高度15km(basedon lunar(月半径1738km基準)
radiusof
1738km)
高度7km(対月面)
Altitude
7km(towards
Moon
surface)© JAXA

垂直降下 descent
VerticalLanding sequence
after start ofpowered descent5

Precise location information of the target landingsite
Target landing site for SLIM*1 (Mean Earth/Polar Axis System (ME))
Longitude : 25.24889 [deg] / Latitude : -13.31549 [deg] The latitude and longitude of the target landing site was*1… More precisely, the target landing site was defined via
the lunar image, and the latitude and longitude were atthese values.

previously announced to the first decimal place (except
to collaborative partners such as NASA and ISRO).
 However, the precise landing site is very important, andselected after lengthy discussions for both scientificsignificance and landing safety. This was the exact site
chosen.

(−13.3, 25.2)(−13.3, 25.2)

credit:NASA/LRO©Daichi Fujii, LRO
Credit :X @dfuji1
https://x.com/i/status/1748103951336227113

SHIOLI Crater
6

Actual descent & landing[Before the start of the landing descent] Prior to the start of the powered descent, image matching navigation was performed in threeareas（1/19 23:52:43, 23:54:43, 23:56:45 JST）
 All image matching was successfully completed twice in each area, and orbit correction(guidance calculation) on the spacecraft from the results was successful. The final decision
to begin landing descent was therefore made (at around 23:59 JST).
 The main engines began to fire as planned, and the powered descent phase, the first half ofthe landing descent sequence, began (23:59:58 JST)

動力降下
Powered descentPre-landing lunar orbit.
Elliptical orbit with dimensions
approximately 15 x 600km

Altitude 15km
高度15km(basedon lunar(月半径1738km基準)
radiusof
1738km)
高度7km(対月面)
Altitude
7km(towards
Moon
surface)© JAXA

垂直降下 descent
VerticalLanding sequence
after start ofpowered descent7

Actual descent & landing[During the powered descent phase] After the start of the powered descent, the spacecraft descended almost in line with the planned
trajectory.
 During the powered descent phase, image matching were performed twice in each of two areas,
both completed successfully. In the first area, a position correction of approximately 200m altitude/ 100m horizontal position was applied, and in the second area, a position correction of about 1km
altitude / 200m horizontal position was applied. This was immediately reflected in the planned
trajectory from the guidance recalculation.
 At the end of the powered descent phase, the spacecraft was at an altitude of approximately 6.2km
as planned, with a good horizontal position error of less than about 100m. The vertical descentphase then began.
動力降下Powered descentPre-landing lunar orbit.
Elliptical orbit with dimensions
approximately 15 x 600km

Altitude 15km
高度15km(basedon lunar(月半径1738km基準)
radiusof
1738km)
高度7km(対月面)
Altitude
7km(towards
Moon
surface)© JAXA

垂直降下 descent
VerticalLanding sequence
after start ofpowered descent8

Actual descent & landing[During the vertical descent phase] After entering the vertical descent phase, altitude measurements by the landing radar weresuccessfully initiated.
 Image matching was performed twice each at an altitude of approximately 4000m and 500m, andthis was successful. The amount of horizontal position correction was about 100m and 50m,
respectively, and the resulting position correction control was also successfully implemented.
 At an altitude of 50m, image-based obstacle detection was also successfully performed, and thespacecraft autonomously identified the safest location in the image, which was then used at the
final landing target.
 Based on this information, we believe that the landing descent to an altitude to 50m was very good.
動力降下Powered descentPre-landing lunar orbit.
Elliptical orbit with dimensions
approximately 15 x 600km

Altitude 15km
高度15km(basedon lunar(月半径1738km基準)
radiusof
1738km)
高度7km(対月面)
Altitude
7km(towards
Moon
surface)© JAXA

垂直降下 descent
VerticalLanding sequence
after start ofpowered descent9

Evaluation to ~50m altitude / image matching Image matching navigation was conducted twice on the spacecraft for all seven areas, and allcompleted successfully.
 For the purpose of ground support in the event of an anomaly, image matching using a morecomputationally intensive algorithm was also performed on the ground based on the images
transmitted from the spacecraft.
 All the results were consistent, and all 14 image matching navigation resulted were determined tobe accurate.

Lunar surface image

Lunar surface topographic map near the location estimatedby the onboard image navigation (CG)10

Evaluation to ~50m altitude / obstacle detection
 Obstacle detection was performed twice, both times completed successfully.
 The images used for detection were later evaluated and all the sites chosen are believed
to have been relatively safe.
 The result from the second detection was adopted for the final landing target (about
12m east-southeast from the previously set landing target)
Approximate location of landing target point
N→

E
↓

N→

E
↓
Obstacle detection #1 results（Red dots. Red box is the spacecraft footprint
including guidance errors）

Obstacle detection #2 results（Red dots. Red box is the spacecraft footprint
including guidance errors）※ images squired from the SLIM navigation camera (CAM-MZ)
11

Evaluation to ~50m altitude / toward the target
site The evaluation was conducted using

Chandrayaan-2:ISRO/SLIM:JAXA

images from Chandrayaan-2, which has
relatively high resolution and was also
used in the selection of the landing target

CV1(VLD1)
Image rangesite.
 Specifically, the task was to find featuresin the Chandrayaan-2 image in common
with the navigation camera image andidentify the area where the two images

HV2
Image range
HV1(VLD2)
Image range

overlapped.
 The right figure shows the situation at two
altitudes (CV1, HV1) and during obstacle
avoidance (HV2). The central blue dot andSequence

Assumedaltitude

Horizontal
distance fromlanding site As the altitude drops and the spacecraft

CV1(VLD1)

4km

103m

approaches the lunar surface, the centre

HV1(VLD2)

500m

42.5m

of the field of view of the navigation

HV2#1

50m

3.4m

camera gradually approaches the target

HV2#2

50m

10.2m

the red dot is the target landing site
selected prior to launch.

landing site, as a result of the navigation
guidance control.

※ Images from SLIM CAM-MZ superimposed
12Evaluation to ~50m altitude / pinpoint landing
accuracy
 Lower right figure shows an enlarged view of the vicinity of the image for obstacle avoidance. Blue dots
indicate the centre position of the first (#1) and second (#2) image capture (blue box), which corresponds
to the horizontal position of SLIM, and its distance

Chandrayaan-2:ISRO/SLIM:JAXA

from the target landing site is shown in the lower

HV2（obstacle detection）#2
Image range

right table.
 From the figure, it was estimated that the positional
accuracy during the obstacle detection is estimatedas about 3 ~ 4m for #1 and 10m for #2.

SLIM footprint（incl. guidance error ） As mentioned above, after this altitude, the landing
target position was reset with priority given to

Landing site

HV2#2
HV2#1

landing safely (obstacle avoidance). Therefore the

11.8m

pinpoint accuracy is estimated to be approximately

Centre of safe area

10m or less.
 Furthermore, #2 is highly likely to have alreadydrifted eastwards due to the abnormal event
described below, and the actual pinpoint accuracy islikely to have been about 3 ~ 4 m.

HV2（obstacle detection）#1
Image range*CAM image is fitted to Chandrayaan-2 image.

After obstacle avoidance, landing is aimed at the centre of the safe areain the diagram. Safety is now prioritised by selecting to avoid obstacles
ahead of accurately landing at the target site (the spacecraft therefore
aimed at a site 11.8m away from the target site). Pinpoint landing
accuracy is therefore evaluated before the obstacle avoidance.

Sequence

Assumedaltitude

Horizontal
distance fromlanding site

HV2#1

50m

3.4m

HV2#2

50m

10.2m

13

Event occurrence at an altitude of approx. 50m
 The spacecraft descended smoothly to an altitude of approximately 50m, but close to this point, anabnormality occurred in the propulsion system.
 Specifically, at around 00:19:18, the total thrust generated by the two main engines suddenly
decreased to about 55%.
 Examination of the temperature behaviour after landing revealed that the –X side of the two main
engines was not exhibiting the expected temperature increase (propellent value temperature rises
due to heat soak-back).
 It is therefore likely that an abnormality occurred in the –X side main engine at this altitude.

00:19:18JST
 The brown line is the accumulated
injection time of the main engine,
and the green line is theacceleration measured by theaccelerometer, which detects theacceleration generated by the
injection of the two main engines.
 Although the injection instruction
to the main engines remained
almost constant, the total thrustgenerated as measured by theaccelerometer suddenly dropped
to about 55% after 00:19:18.
14

Event occurrence at an altitude of approx. 50m
 Two navigation camera images taken near the time of the abnormality are shown below
 Immediately after the abnormality in the main engine thrust, the navigation camera images show
spots of light and objects that had not been seen in the previous image
 Since one of these has a nozzle-like shape, it is assumed that some kind of abnormality occurred
near the main engine on the –X side at around 00:19;18, causing the nozzle to break and fall,resulting in the loss of most of the thrust generated by the main engine on the –X side

00:19:14(JST)00:19:20(JST) The blue arrow indicatesthe corresponding featurein both images
 The red arrows show spotsof light or objects not seenin the left image

15

Event occurrence at an altitude of approx. 50m
 A total of eight post-launch trajectory changes and the power descent phase have used the main
engine under higher supply pressure and higher engine load conditions, but the main engine has
not shown any signs of abnormality until just prior to this event.
 Moreover, comparison of the two main engines at the time of the incident suggests that the –X side
engine has mild combustion conditions compared to the +X side engine.
 The Project therefore believes that it is highly likely that an
external factor and not the main engine itself affected the –X
side main engine.
 The cause is still being investigated and there will be further
reports when more details are available.

 Example of main engine related data. SLIM uses a blowdown
propulsion system, designed to gradually reduce the propellant
supply pressure. After launch, the supply pressure of both fueland oxidizer gradually decrease as propellant is consumed, andthe load on the engine also decreases (see top diagram).
 The mixing ratio (MR) of oxidizer and fuel is another importantfactor that determines the load on the engine, but the MR ofthe –X size engine is believed to be always lower than that of
the +X side engine and therefore, the load on the –X side
engine was relatively smaller than that on the +X side engine.
16

Estimation of behaviour after the abnormality
occurred
Current estimate of the spacecraft behavior after the abnormality occurred at around 00:19:18.
 The abnormality occurred while the spacecraft was hovering. One of the two main engines was lost
due to an abnormality, but the dual main engine design allowed a certain level of redundancy to
avoid a situation where a moon landing would have been impossible.
 However, a single main engine could only generate a thrust equivalent to the lunar gravity, making it
difficult to fully control the descent speed. The spacecraft continued to descent at a rate of 2 ~3m/s from around 50m.
 The two main engines were also designed to cancel each other’s lateral thrust, so the loss of one
engine on the –X side produced a horizontal velocity toward the –X side.
 At the end of hovering, the onboard navigation guidance control system detected an abnormality
and executed a mode transition. The spacecraft continued to fire the main engine while changing
the attitude to reduce lateral movement, and autonomously proceeded with the sequence towards
the landing mode sequence. During this process, LEV-1 and LEV-2 (SORA-Q) were separate at analtitude of about 5m.
 With a lateral velocity, the spacecraft landed in an almost upright standing position (at about
00:19:52). The rate of descent upon landing was about 1.4 m/s, which is slower than the specified
range (1.8 ~ 2.8 m/s). However, landing conditions such as the lateral velocity and attitude
exceeded the specified range and produced a large attitude fluctuation after landing that resulted
in a settled attitude different to expected.

17

Estimated landing site
 Relationship between the spacecraft position at the time of obstacle detection and the estimatedlanding point. The spacecraft moved east from its position during its nominal descent (about 55m
to the east)

Chandrayaan-2:ISRO/SLIM:JAXA

HV2（obstacle detection）#2
Image range (horizontal error approx. 10.2m)

着陸目標点

シーケンス

想定高度

着陸目標点との
水平距離

HV2#1

50m

3.4m

HV2#2

50m

10.2m

SLIMフットプリント（誘導誤差含む）

11.8m
安全領域中心

着陸地点

Landing position was
estimated by NASA JPL,
based on an image
captured by NASA LRO.

HV2（obstacle detection）#1
Image range (horizontal error approx. 3.4m)*CAM image is fitted to Chandrayaan-2 image.

18

Estimated landing site
 After landing, the final attitude of the spacecraft is believed to be an almost vertical
position with the main engine facing upwards and the solar panels facing west, as shown in
the figure, based on data from the spacecraft.

CG image created from the estimated landing position and attitude
Credit：JAXA / CG Production：Mitsubishi Electric Engineering Corporation

W
19

Operation immediately after landing Immediately after it was determined that the spacecraft had landed, it was confirmed that power
was not being generated from the solar cells.
 Since communication with the spacecraft had been established, the pre-arranged abnormality
response procedures were implemented in sequence.
 Operation summary (dated 01/20)
 0:20 ~ around 1:30

Data download from spacecraft, unnecessary equipment turned off,

turn off heaters etc.
 1:30 ~ around 1:50

Transition to NASA Deep Space Network (DSN) station operation due

to to end of domestic ground station visibility hours.
Trials to reduce power consumption by changing communication settings.
 1:50 ~ around 2:35

Taking into account remaining battery level, we decided to startobservation using the multi-band spectroscopic camera.
 2:57

Battery disconnected from power system by command, and spacecraft power

was turned off.
 The above operation allowed retrieval of all the technical data and image data recorded on thespacecraft during the landing descent.
 Battery disconnection was a measure to avoid the permanent loss of the spacecraft due to overdischarge. Since SLIM can operate once power generated from the solar cells exceeds the required
level, it is expected to operations will resume once the generated power is restored in the future.
20

Observation with the multi-band spectroscopic
camera (on the day of landing) Observations with the multi-band spectroscopic camera (MBC) were conducted
for approximately 45 minutes after landing. Implementation details:
 Single-band imaging with launch lock (exposure time determined by theauto-exposure) Launch lock release Scan imaging
 To prevent the temperature of the spacecraft transmitter from exceeding theguaranteed operating temperature, instead of capturing 333 image in 35 minutes,
the scan was terminated after 15 minutes. 257 of the 333 images were therefore
taken and downloaded.

 In the above operation, the launch lock for the movable mirror was successfully
released and the movable mirror operated normally. The auto-exposure function
and single band imaging also worked as expected.
 In addition, from the images obtained by the image scan, observation candidate
targets were identified that are expected to yield scientific results in moredetailed observations.
21

【Note】 multi-band spectroscopic camera (MBC) SLIM’s target landing site, located near SHIOLI crater, was selected from the places where rocks ejected fromluna mantle is thought to exist.
 After successful landing, MBC onboard SLIM carries out 10-band spectroscopy observation.
 Rocks estimated to be derived from luna mantle will give us important hint to unravel the origins of theMoon.
 A prevailing theory on the Moon’s origin is “giant-impact hypothesis”, however, the details of the impact is underdiscussion. Especially, it is still unrevealed which one mainly form the moon, ejecta from the Earth or the impactor.
 Key information to answer this question is the lunar mantle’s composition, mineral composition ratio or the ratio
between iron and magnesium.
 MBC has capability to analyze the composition of the target rock with 10-band spectroscopic observation. After
successful landing, MBC observes rocks or regolith around the landing point, and try to estimate the lunar mantle’s
composition.
 Note that this observation becomes possible only when the lander can land at specific target precisely.

(−13.3, 25.2)(−13.3, 25.2)

gimballaunch rock for
FOV rotation
mechanismlaunch rock forfocus mechanism

SHIOLI crater
NASA/LROSLIM target landing site
（left：location on the Moon、right：closed-up viewaround SHIOLI crater）

MBC and its mounting position on SLIM

22

Observation with the multi-band spectroscopic
camera (on the day of landing)
Image mosaic obtained by joining the 257 images from the scan imaging
Image capture
range of one
image shot

Originally, the rightside of the image
should have beenin the upward
direction.
White areas arewithout data
because the scan
was terminated at
the half-way point.
Indicate
candidateobservation
sites
JAXA, RITSUMEIKAN UNIVERSITY, THE UNIVERSITY OF AIZU

23

Observation with the multi-band spectroscopic
camera (on the day of landing)Simulation image

Landscape simulation
based on DTM of
KAGUYA TC

CAM-PX:JAXA
MBC:JAXA, RITSUMEIKAN UNIVERSITY, THE UNIVERSITY
OF AIZU

Navigation camera (CAM-PX) matching with multi-band spectroscopic camera (MBC) scan images.
Slightly whitish are in the upper right is the CAM-PX image

24

Results of ultra-small rovers,
LEV-1 and LEV2 (SORA-Q)
Just before landing, SLIM deployed two ultra-small rovers, LEV-1 and LEV-2 at analtitude of about 5m.
 LEV-1 and LEV-2 worked on the Moon surface fully autonomously, and in acooperative manner.
 LEV-1 carried out experiments of hopping locomotion.
 LEV-2, also known as “SORA-Q”, succeeded to take a snapshot of SLIM. The
image data was transmitted to LEV-1 via Bluetooth, and LEV-1 directlytransmitted the data to the Earth (Fully autonomous and cooperated).
 Note that LEV-1 weighs approx. 2.1kg, and LEV-2 only weighs approx. 0.25kg.
*1 … SORA-Q was developed by JAXA/TOMY Company/Sony/Doshisha Univ.

LEV-1

LEV-2(SORA-Q)

Artist image of the ultra-small rovers (LEV-1, LEV-2) on the moon25

Results of ultra-small rovers,
LEV-1 and LEV2 (SORA-Q)
Captured by LEV-2’s front camera, then transmitted to the Earth by LEV-1.

 LEV-2 selected “the bestshot”, which effectively
captured SLIM and its vicinity,
through several taken images.
 Then sent the image to LEV-1
via Bluetooth, and LEV-1 sent
it to the Earth directly.
 NO ground support for thesebehavior. It was fullyautonomous.
 Note that again, LEV-1 weighsapprox. 2.1kg and achieved
direct transmission to the
Earth. LEV-2 provided us thisimpressive photo without any
ground support, although
only weighs approx. 0.25kg.
26Operation after power restoration
 According to the change of sun direction, the condition to generate electric
power was gradually restored. Finally, the communication with SLIM lander was
established again on the night of 28th, January.
 After the basic health check on the SLIM lander, soon the observation withmulti-band spectroscopic camera was started.
 Scientific observation team succeeded 10-band spectroscopic observation on
10 target rocks. The number of observed rocks exceeds the expectations before
landing.
 They started the analysis on the observed data, to identify the type of the rocks
and estimate their mineral composition.

 After MBC observation, the location of landing became night on 31st, February.
SLIM lander is now turned-off again.
 Although SLIM lander is not designed to survive the moon night condition, we
will try to establish the communication and try several operations include MBC
observation again in late February.

27

Operation after power restoration
 Left phot is the 10 target rocks in the 10-band spectroscopic observation after
the power restoration. Due to the change of solar illumination conditions, target
rocks are selected again after the restoration.
 Right photo is the detailed image with 1-band（1.65μm） on “AKITAINU”.

JAXA,
Ritsumeikan University,
University of Aizu

Automatically focused with MBC,
and as a result, the distance isestimated to be about 18m, andthe size of AKITAINU is estimated
JAXA, Ritsumeikan University, University of Aizu

to be about 63cm in width.

28

Summary (results from moon landing descent 1/2)
 SLIM successfully conducted the landing descent operation until an altitude of about 50m, justprior to performing obstacle avoidance.
 In particular, all 14 image-matching navigation steps, including the navigation results, wereconducted normally.
 The appropriate point to evaluating the pinpoint landing accuracy of SLIM is just before obstacle
avoidance. The result of that evaluation indicate a pinpoint landing accuracy of less than 10m, andprobably about 3~4m.
 At an altitude of approximately 50m, an abnormality occurred which resulted in the loss of one of
the two main engines.
 Due to having a level of redundancy, SLIM did not suffer a catastrophic failure that would prevent
landing, but continued a slow descent and moved gradually to the east. The ultra-small rovers(LEV-1 and LEV-2 (SORA-Q)) were successfully separated at an altitude of about 5m and delivered
to the Moon’s surface. The spacecraft landed at a descent rate lower than the specified range.
However, as landing conditions aside from the descent rate were outside the specified range, thespacecraft settled at a different attitude than expected.
 The landing location is estimated to be about 55m east of the landing target. The attitude after
stabilization is considered to have the solar panels facing west, and the Sun was positioned to theeast at the time of landing, resulting in a loss of power generation by the solar cells.
29Summary (results from moon landing descent 2/2)
 After landing, communication with the spacecraft was established, but power
generation from the solar cells could not be confirmed. Therefore, in
accordance with the abnormality situation response procedure, data including
images during the landing descent were acquired, scan imaging was initiatedwith the multi-band spectroscopic camera, and the battery disconnected fromthe power supply on command in order to maintain spacecraft functionality. This
causes SLIM to power off.
 According to the change of sun direction, the condition to generate electric
power was gradually restored. Finally, the communication with SLIM lander was
established again on the night of 28th, January.
 Scientific observation team succeeded 10-band spectroscopic observation on
10 target rocks.
 The location of landing became night on 31st, February, and SLIM lander is now
turned-off again.
 We will try to establish the communication and try several operations include
MBC observation again in late February.

30

Summary（results & issues）
 Although detailed data evaluation needs to be continued, it is believed that SLIM was able todemonstrate the landing technology for all the planned engineering test items, with the exceptionof the two-step landing dynamics.
 In particular, the demonstration of the image matching technology and pinpoint landing accuracyof less than 10m (perhaps 3~4m) has been achieved is a major accomplishment for future lunar
and planetary exploration.
 Regarding the lunar activities after landing, the operation of LEV-1 and LEV-2 (SORA-Q) on the
lunar surface, after successful separation from the SLIM lander and delivery to the surface, hasbeen confirmed, and these were successfully delivered to the Moon’s surface. Multi-band
spectroscopic camera achieved 10-band spectroscopic observation on 10 target rocks, thus
further scientific results can be expected.

 On the other hand, it is necessary to conduct a detailed study on the abnormal events that
occurred before and after the obstacle detection to identify the causes and clarify issues andcountermeasures for the future.
 The engineering technology developed for SLIM, including the two-step landing dynamics that
could not be demonstrated this time, will be organised and prepared for transfer to future
missions.
 The results of future operations and studies are intended to be announced in a timely manner.
31

Summary（results & issues）
Engineering test target items
Minimum
success

status

Evaluation etc.

Develop image-matching navigation, which isessential for high-precision landing, and combine
this with other navigation systems to result in anavigation error of about 100m.

Achieved

All 14 image matching runs conducted on orbit werecompleted successfully. Based on the landing accuracy
obtained, the navigation accuracy was evaluated to beless than 10m.

Provide a simple shock-absorbing mechanism forsoft-landings

Under
investigationRealise a compact, lightweight, high-performancechemical propulsion system.

UnderinvestigationAchieved

A compact and lightweight computer and power supply
system were developed and installed. Both instrument
functioned normally from launch to post-landing,contributing to the success of the pinpoint landing.

Achieved

The landing guidance rules worked well before andafter the obstacle detection, demonstrating theperformance of the pinpoint landing. The obstacle
detection results were also confirmed to be valid.

A high-precision landing (accuracy of 100m) on
the Moon’s surface performed by a spacecraft
equipped with these technologies, and results
verified.

Achieved

Based on evaluations near obstacle detection, pinpoint
landing accuracy was less than about 10m (perhaps
3~4m). Even after the subsequent events, thespacecraft is estimated to have landed about 55mfrom the target landing site.

Spacecraft remained functional after landing.

Achieved

After landing, the spacecraft continued to operate,and data obtained during the landing descent was
reproduced and received on the ground.

After reaching the Moon’s surface, the mission
continued for a period until sunset.

Ongoing

Once power generation from the solar cells is resumed,
observation operations are planned with the multiband spectroscopic camera for a period of time.

Weight reduction of the core elements of thespacecraft, including the computer and power
supply system.

FullsuccessExtra
success

Realise autonomous landing guidance rules that
can take into account navigation guidance errors
while detecting obstacles.

※ The overview of Project objectives were quoted in the press kit and other descriptive
documents, but given in more detail in this report for the purpose of comparison.

32

From the era of “Landing where we can”
to “Landing where we want”

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Image credit throughout this document is JAXA (unless otherwise stated)