ESA stopped maintaining ExoMy in 2021, and updates now come from a single community-run successor repo.
A small six-wheeled rover modeled on ESA's Rosalind Franklin ExoMars rover, developed in ESA's Planetary Robotics Laboratory. Its rocker-bogie style body is almost entirely 3D printed, every wheel can be steered, and a Raspberry Pi with a camera runs ROS inside Docker, so the rover can drive in Ackermann, spot-turn and crab modes from a gamepad or a web page. ESA archived its own repositories in 2021, and a community successor repo now carries the files and wiki.
At a glance
| Parts cost | $280–$560 (2020) project · The project says its own build cost around 500 EUR, or 250 to 500 EUR depending on parts already owned. Its purchasing list totals about 515 EUR including a 47 EUR gamepad source ↗ |
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| Difficulty | 3/5 Intermediate · Off-the-shelf parts and a detailed photo guide, but it needs a long print job, a soldered harness, opening six servos to cut PCB pins, and Docker/ROS setup on the Pi. |
| Build time | About 2-3 weeks overall (about 1-2 weeks of printing on one printer, half a day of electronics, 1-2 days of assembly) source ↗ |
| Tools needed | 3D printer with at least 202 x 202 x 110 mm build volume (about 1.5 kg of PLA, 1-2 weeks of printing), soldering iron, pliers and multimeter for the wire harness and PWM HAT, soldering iron tip for M3 heat-set inserts, deburrer and carving tools for support removal (optional) |
| Motors | 12 Parallax servos (6 continuous-rotation for driving, 6 standard for steering, the steering ones modified to reroute their cable) |
| Controller | Raspberry Pi 4 with Adafruit 16-channel PWM servo HAT, powered from a 3S 3000 mAh LiPo via two DC/DC converters |
| Sensors | Raspberry Pi Camera V2 |
| Published | ✓ Parts list✓ CAD/STL✓ Assembly guide✓ Wiring✓ Software✗ Video GitHub wiki (step-by-step photo guides) + release zip with STL/STEP/SLDPRT, parts list spreadsheet, print settings and Fritzing schematics; only a timelapse video |
| Activity | Last update 2025-11-19 · 292 GitHub stars · Discord server linked from the README (size unknown); ESA repo 292 stars / 47 forks (archived), successor repo 39 stars / 9 forks; ESA Academy used ExoMy rovers in a 2024 student robotics workshop |
| Kits | None found (unconfirmed) |
Licenses
| Design files | GPL-3.0 (repo-wide LICENSE of the documentation repo, which holds the STL/STEP/SLDPRT release files) source ↗ |
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| Code | GPL-3.0 source ↗ |
| Documentation | None found (GitHub wiki has no license statement; project website footer shows only a template copyright line) source ↗ |
Builder notes
Practical points from the project's issue tracker, forum and docs, each linked to its source.
- ESA's original repos are archived. The successor repo by a community builder published release v1.0.3 in 2024 and updated the wiki for 64-bit Raspberry Pi OS (Bookworm), so its wiki is the one to follow rather than the esa-prl copy. source ↗
- The rover needs 12 servos in total, six continuous and six standard. Early builders misread the collapsed parts list item numbers as quantities, and the spreadsheet once hid rows behind an accidental filter. source ↗
- Screws are threaded straight into 4 mm printed holes. On a well-calibrated printer these can come out loose, so the wiki now suggests test-printing the bogie bearings and wheel parts before printing all six, and some builders tighten holes in the slicer or switch to brass inserts. source ↗
- After a few hours of driving, the motor cables can rub on the wheels and bogie bearings. Builders wrap exposed runs in electrical tape and hold the cables up with rubber bands, a fix later added to the Bogie Assembly page. source ↗
- On 64-bit Raspberry Pi OS the camera stays dark until the legacy camera settings are enabled in config.txt. The STEP file for the drill part also contained the wrong geometry until v1.0.3 (the STL was fine). source ↗
Other rovers plans
- Sawppy the Rover · $500 (2018) · difficulty 3/5
- NASA JPL Open Source Rover · $1,400 · difficulty 4/5