Skip to content
Space Robotics

SORA-Q

Program pages JAXA Space Exploration Innovation Hub Center: Transformable nano rover LEV-2 (SORA-Q)

SORA-Q in its deployed running configuration on a regolith simulant bed. The two hemispherical shells have opened out into wheels, the yellow front camera housing stands proud of the body between them, and the tail stabilizer trails behind in the dust JAXA / TOMY Company / Sony Group Corporation / Doshisha University.

Overview

Section titled “Overview”

SORA-Q, formally Lunar Excursion Vehicle 2 (LEV-2), is a spherical nano-rover that opens into a two-wheeled running configuration on the lunar surface [1]. It was developed jointly by JAXA, TOMY Company, Sony Group Corporation and Doshisha University, and flew inside the SLIM lander, which launched on 7 September 2023 and landed on 19 January 2024 UTC [10]. TOMY entered the program through a 2016 JAXA request for proposals aimed at building an inexpensive insect-scale robot from consumer toy technology; Sony joined in 2019 with responsibility for control boards and sensors, and Doshisha University joined in 2021 on mechanism design alongside TOMY [7].

Specifications

Section titled “Specifications”
ParameterValueSource
Stowed formsphere, 80 mm diameter[1], [7]
Mass228 g[7], [10]
Deployed configurationtwo hemispherical shells opened into wheels, tail stabilizer, cameras[1]
Wheel driveeccentric wheel rotation, to limit sinkage in soft regolith[1]
Camerastwo, one forward, one aft[7]
Control and image-processing hardwareSony Semiconductor Solutions Spresense smart sensing processor board, a consumer IoT part[5]
Autonomyfull, no ground commanding[5], [6]
Communicationsshort-range wireless link to LEV-1, which relays to Earth[9]

No rated drive speed, gradeability, obstacle height, battery capacity or operating temperature range is published on the JAXA pages.

Mission profile

Section titled “Mission profile”
ParameterValueSource
LaunchH-IIA F47 from Tanegashima, 7 September 2023[10], [11]
Separation from SLIM15:19:52 UTC, immediately before touchdown, 19 January 2024[10]
Surface imaging success20 January 2024 JST[5]
SLIM landing massabout 200 kg[10], [11]
SLIM landing accuracybetter than 10 m[10], [11]

The telemetry and photogrammetric analysis released with the Science Robotics paper adds:

ParameterValue
Documented surface operating timeat least 108 minutes
Onboard image-processing runs executed240
Images returned from the lunar surface2
Estimated standoff from SLIM when the front-camera image was taken5.08 m
Distance driven between the two imagesabout 0.13 m
Rotation between the two imagesabout 180 degrees

Source: [6].

SLIM lost most of the thrust from one of its two main engines during descent. Because the two engines were mounted with a slight tilt, the surviving thrust still passed roughly through the center of gravity and attitude control held, but the previously canceled lateral component drove an eastward drift, and SLIM touched down about 60 m east of the target with its solar cells facing west instead of the planned zenith orientation [10]. LEV-1 and LEV-2 had already separated at that point.

Mobility

Section titled “Mobility”

The vehicle stows as a sphere 80 mm across and deploys by opening its two hemispherical shells outward into wheels, extending a tail stabilizer and raising the cameras [1], [7]. Locomotion uses an eccentric wheel rotation mechanism, chosen so that the small wheels do not bury themselves in soft lunar regolith. Sinkage of a small wheel in soft ground is the stated design driver [1].

Flight evidence of mobility comes from image analysis rather than odometry. A rock appears in both of the two returned surface images. Registering the two on that rock gives about 0.13 m of travel and about 180 degrees of rotation between the exposures, which confirmed that the transformation mechanism and the eccentric wheel rotation both worked in the real lunar environment [6]. That the vehicle had deployed from its stowed sphere and driven at all was already established in January 2024 from the first returned image [5].

Power and energy

Section titled “Power and energy”

The vehicle runs on internal batteries; no generation source is described in the JAXA material. Energy efficiency and lifetime extension were among the toy-derived technologies named as the basis of the development [7].

Thermal

Section titled “Thermal”

No thermal design values for LEV-2 are published.

Compute and avionics

Section titled “Compute and avionics”

Sony led development of the control system and the image-processing software, built around the Sony Semiconductor Solutions Spresense smart sensing processor board, a commercial IoT part [5]. JAXA’s stated result from that choice is a demonstration that consumer devices can be used in the space environment [5].

The image-processing chain ran 240 times on the lunar surface [6]. Telemetry analysis confirmed that the onboard processing correctly recognized the lander in the imagery it took [6].

Autonomy

Section titled “Autonomy”

Autonomy was complete: after separation the vehicle powered up, deployed, righted itself, moved away from the lander while imaging, chose which of the images to send, and transmitted them, with no commands from the ground [6], [5]. Image selection was done by an onboard algorithm that picked frames in which SLIM was well framed [5]. The design premise was a communication environment too constrained for teleoperation [6]. Anomaly detection and self-recovery functions also ran autonomously, and the attitude anomaly encountered during driving was handled onboard [6].

Communications

Section titled “Communications”

LEV-2 has no direct link to Earth. It transmits over a short wireless link to LEV-1, which carries a 90 g transmitter and returns the data direct to Earth from the lunar surface [3]. LEV-1 relayed the data without routing it through SLIM itself [9]. The first surface image was returned through that path and confirmed the LEV-1 to LEV-2 inter-robot link working [5], [12]. Both returned images suffered data dropouts in transmission: the front-camera image is partially missing, and only the left portion of the rear-camera image was reconstructed [6].

Payload and instruments

Section titled “Payload and instruments”

Two optical cameras, one facing forward and one facing aft [7]. Their purpose is imaging the spacecraft and the surrounding environment. The front camera returned the image in which onboard processing detected SLIM [6]; the rear camera returned the second image, released in June 2026, whose surviving left portion carries the rock used to establish that the vehicle had moved [6].

Modes of operation

Section titled “Modes of operation”

The published sequence is stowed transit inside SLIM, separation, automatic deployment from sphere to running configuration, attitude righting, drive and image, onboard image selection, transmission to LEV-1, with anomaly detection and posture recovery as an off-nominal branch exercised in flight [6].

Ground operations

Section titled “Ground operations”

There were no ground operations during the surface phase. Analysis was retrospective: the walking log and other data were still being processed when the first results were published in January 2024 [5], and the second image and the telemetry-derived operating time, image processing count and posture-recovery result were released with the Science Robotics paper in June 2026 [6].

Technologies developed

Section titled “Technologies developed”

The program’s stated result is that a palm-sized robot built substantially from consumer toy and IoT technology can carry out an autonomous surface exploration sequence, and JAXA names three directions it opens: operating several small robots at once to cover ground efficiently, pairing small robots with a large rover, and reaching terrain such as caves and steep slopes that has been inaccessible [6]. The Spresense-based control system is cited as evidence for consumer parts in the space environment [5].

References

  1. Hirano, D., Inazawa, M., Sutoh, M., Sawada, H., Kawai, Y., Nagata, M., Sakoda, G., Yoneda, Y. and Watanabe, K. (2024). Transformable Nano Rover for Space Exploration . IEEE Robotics and Automation Letters, 4. Source
    BibTeX
    @article{hirano2024transformable,
  title = {Transformable Nano Rover for Space Exploration},
  author = {Hirano, Daichi and Inazawa, Mariko and Sutoh, Masataku and Sawada, Hirotaka and Kawai, Yuta and Nagata, Masaharu and Sakoda, Gen and Yoneda, Yousuke and Watanabe, Kimitaka},
  journal = {IEEE Robotics and Automation Letters},
  volume = {9},
  number = {4},
  pages = {3139--3146},
  year = {2024},
  doi = {10.1109/lra.2024.3363529},
  abstract = {This letter introduces a novel nano rover designed to transform its shape for efficient movement on lunar surfaces. The rover, resembling a compact ball, has a diameter of roughly 80 mm and a mass around 250 g. Its transformational mechanism allows for compactness during planetary transportation, with enhanced mobility achieved through the use of extendable wheels, a tail stabilizer, and cameras. To traverse soft terrains efficiently, the rover utilizes an eccentric wheel mechanism, offering two distinct movement modes based on wheel synchronization. This mechanism provides a locomotion velocity of 20 mm/s or more on a flat surface. Moreover, it features onboard image processing to detect spacecraft shielded by Multi-Layer Insulation (MLI) films, facilitating autonomous control and selective image transmission. This rover has been deployed in a real space mission, having been mounted on a lunar lander. This letter presents the design specifics of this transformable rover and results from field tests simulating lunar conditions. These tests affirmed the efficacy of the proposed motion mechanism and onboard image processing.}
}
  2. JAXA. (2024). Results and achievements of the Lunar Excursion Vehicle (LEV-1) on board the Smart Lander for Investigating Moon (SLIM). jaxa.jp/press/2024/01/20240125-2_j.html
    BibTeX
    @misc{jaxa2024results,
  title = {Results and achievements of the Lunar Excursion Vehicle (LEV-1) on board the Smart Lander for Investigating Moon (SLIM)},
  author = {{JAXA}},
  organization = {jaxa.jp},
  year = {2024},
  url = {https://www.jaxa.jp/press/2024/01/20240125-2_j.html}
}
  3. JAXA, TOMY Company, Sony Group Corporation and Doshisha University. (2024). Successful image capture and data transmission of the SLIM lander by the transformable lunar robot. jaxa.jp/press/2024/01/20240125-4_j.html
    BibTeX
    @misc{jaxa2024successful,
  title = {Successful image capture and data transmission of the SLIM lander by the transformable lunar robot},
  author = {{JAXA} and {TOMY Company} and {Sony Group Corporation} and {Doshisha University}},
  organization = {jaxa.jp},
  year = {2024},
  url = {https://www.jaxa.jp/press/2024/01/20240125-4_j.html}
}
  4. JAXA, TOMY Company, Sony Group Corporation and Doshisha University. (2026). Lunar demonstration results of the transformable lunar robot LEV-2 published in Science Robotics. jaxa.jp/press/2026/06/20260618-1_j.html
    BibTeX
    @misc{jaxa2026lunar,
  title = {Lunar demonstration results of the transformable lunar robot LEV-2 published in Science Robotics},
  author = {{JAXA} and {TOMY Company} and {Sony Group Corporation} and {Doshisha University}},
  organization = {jaxa.jp},
  year = {2026},
  url = {https://www.jaxa.jp/press/2026/06/20260618-1_j.html}
}
  5. (2026). JAXA Space Exploration Innovation Hub Center: The Transformable nano rover (Lunar Excursion Vehicle 2, SORA-Q). ihub-tansa.jaxa.jp/english/LEV2_en.html
    BibTeX
    @misc{jaxaihublev2,
  title = {JAXA Space Exploration Innovation Hub Center: The Transformable nano rover (Lunar Excursion Vehicle 2, SORA-Q)},
  organization = {ihub-tansa.jaxa.jp},
  year = {2026},
  url = {https://www.ihub-tansa.jaxa.jp/english/LEV2_en.html}
}
  6. Otsuki, M. (2024). The companionable micro lunar exploration rovers LEV-1 and LEV-2 . ISAS News, 518. isas.jaxa.jp/feature/slim/slim_09.html
    BibTeX
    @misc{otsuki2024companionable,
  title = {The companionable micro lunar exploration rovers LEV-1 and LEV-2},
  author = {Otsuki, Masatsugu},
  journal = {ISAS News},
  number = {518},
  organization = {isas.jaxa.jp},
  year = {2024},
  url = {https://www.isas.jaxa.jp/feature/slim/slim_09.html}
}
  7. Sakai, S., Kushiki, K., Sawai, S., Fukuda, S., Miyazawa, Y., Ishida, T., Kariya, K., Ito, T., Ueda, S., Yokota, K., Kawano, T., Ohtake, M., Saiki, K., Nakauchi, Y., Michigami, K., Furukawa, K., Akizuki, Y., Kanaya, S., Kinjo, T., Goto, K., Sawada, K., Sugimoto, Y., Takeuchi, H., Tomiki, A., Toyota, H., Nagata, T., Nakatsuka, J., Maki, K., Mizuno, T., Shiratori, H., Nishino, M. N., Usami, N., Kikuchi, J., Hamori, H., Hirasawa, R., Shibasaki, Y. and Saito, H. (2025). Moon landing results of SLIM: A smart lander for investigating the Moon . Acta Astronautica. Source
    BibTeX
    @article{sakai2025moon,
  title = {Moon landing results of SLIM: A smart lander for investigating the Moon},
  author = {Sakai, Shinichiro and Kushiki, Kenichi and Sawai, Shujiro and Fukuda, Seisuke and Miyazawa, Yu and Ishida, Takayuki and Kariya, Kazuki and Ito, Takahiro and Ueda, Satoshi and Yokota, Kentaro and Kawano, Taro and Ohtake, Makiko and Saiki, Kazuto and Nakauchi, Yusuke and Michigami, Keisuke and Furukawa, Katsumi and Akizuki, Yuki and Kanaya, Shusaku and Kinjo, Tomihiro and Goto, Kenta and Sawada, Kenichiro and Sugimoto, Yoshihide and Takeuchi, Hiroshi and Tomiki, Atsushi and Toyota, Hiroyuki and Nagata, Taiichi and Nakatsuka, Junichi and Maki, Kenichiro and Mizuno, Takahide and Shiratori, Hirohide and Nishino, Masaki N. and Usami, Naoto and Kikuchi, Junji and Hamori, Hitoshi and Hirasawa, Ryo and Shibasaki, Yusuke and Saito, Hiroaki},
  journal = {Acta Astronautica},
  volume = {235},
  pages = {47--54},
  publisher = {Elsevier BV},
  year = {2025},
  doi = {10.1016/j.actaastro.2025.05.047},
  abstract = {The Smart Lander for Investigating the Moon (SLIM), with a dry mass of about 200 kg, was launched by the H-IIA vehicle on September 7, 2023, and made a precision lunar landing on January 19, 2024 (Coordinated Universal Time). The landing precision was evaluated to be within ∼10 m at an altitude of approximately 50m from the Moon surface, far exceeding the target landing accuracy of 100 m and realizing the world’s first pinpoint landing, although a trouble occurred just before landing and one of the two main engines lost thrust. The two micro/nano rovers of the SLIM separated immediately before landing and successfully captured SLIM images in fully autonomous operation mode. The operation team also obtained spectroscopic observations of rocks from scientific instruments onboard the SLIM, which are expected to provide clues on the origin of the Moon. Although not designed to endure the harsh temperatures of the lunar day and night, the lander operated after three lunar nights, gathering various engineering data. This paper reports the results of the lunar landing operations of SLIM.}
}
  8. Sakai, S., Kushiki, K., Fukuda, S. and Sawai, S. (2026). Overview of the Small Lunar Lander SLIM and Its Lunar Landing Results . IEEJ Journal of Industry Applications. Source
    BibTeX
    @article{sakai2026overview,
  title = {Overview of the Small Lunar Lander SLIM and Its Lunar Landing Results},
  author = {Sakai, Shinichiro and Kushiki, Kenichi and Fukuda, Seisuke and Sawai, Shujiro},
  journal = {IEEJ Journal of Industry Applications},
  volume = {15},
  pages = {839-848},
  year = {2026},
  doi = {10.1541/ieejjia.20250916},
  abstract = {The Smart Lander for Investigating Moon (SLIM), which was developed by the Japan Aerospace Exploration Agency (JAXA) and launched in September 2023, successfully landed on the Moon on January 20, 2024. Postlanding evaluation confirmed that its precision landing performance was better than 10 m, making it the world's first lunar lander to achieve high-precision landing. Furthermore, the mass at landing was approximately 200 kg, making it one of the lightest landers ever to succeed in a lunar landing. This lightweightness was the result of the development and application of various new technologies for weight reduction. These technologies are expected to be applied to the weight reduction of future lunar and planetary probes, thereby contributing to more frequent lunar and planetary exploration missions. This review article aims to provide an overview of SLIM's achievements by citing or referring to previously published papers.}
}
  9. Yoshimitsu, T. (2024). LEV-1, the Ultra-Small Lunar Surface Exploration Rover Aboard SLIM: Flight Results . Japan Aerospace Exploration Agency, Institute of Space and Astronautical Science. Source
    BibTeX
    @techreport{yoshimitsu2024lev1,
  title = {{LEV-1}, the Ultra-Small Lunar Surface Exploration Rover Aboard {SLIM}: Flight Results},
  author = {Yoshimitsu, Tetsuo},
  institution = {Japan Aerospace Exploration Agency, Institute of Space and Astronautical Science},
  year = {2024},
  url = {https://www.jaxa.jp/projects/files/youtube/ml_slim_lev1_lev2/jaxa_doc02_20240125.pdf}
}

Further reading