Mass

Seventeen rover configurations from eight teams have a published mass of some kind, and thirteen of them are URC competition masses from 2022 to 2026. The values run from 33.0 kg to 53.0 kg with a mean of 47.9 kg and a median of 49.1 kg, which is not an engineering optimum: it is a pile-up against the 50 kg limit, with three configurations exactly at it. The database is small, mostly self-reported and self-selected toward organised teams, and every conclusion on this page is bounded by that.

The database and its coverage

The thin coverage is the finding. A handful of teams produced all thirteen published masses, and four of the five champions published none. A statement that URC rovers typically mass a certain value rests on a self-selected sample, which is why the values here are reported configuration by configuration rather than summarised as a field norm.

The interactive view plots the fourteen configurations that carry a numeric mass. The three estimates that carry an approximation sign, West Virginia 2022 and both Northeastern rovers, are omitted because the chart reads the value as a number.

Where the mass goes

Monash’s public robot description files are the only measured subsystem breakdown in the record. They cover the rolling chassis and the arm, not the battery, electronics or science payload.

Suspension, ankles and the differential bar together are 36 % of the accounted mass, and the wheels are 24 %, more than the arm. That is why wheel architecture is a first-order mass decision: a 0.6 kg printed wheel instead of a 1.85 kg composite wheel saves 5 kg on a four-wheel rover S-MONASH-GH-NOVA. The full three-way allocation, measured against the recommended 49 kg target, is on Subsystem comparisons.

The arm is the only subsystem with more than two independent measurements, and five of them span 4.0×: 3.53 kg for the Cornell arm, 4.42 kg for Toronto’s, 6.54 kg for Monash’s and 9.40 kg for West Virginia’s 5-DoF arm, with ARES at 14.00 kg for a longer arm with a linear stage S-WVU-SAR2025 S-RSX-ARM-URDF S-ARES-PAPER-2025 S-MONASH-GH-NOVA.

Mass against score

Twelve team-years have both a published mass and a same-year official total. The association is negative and holds up under three checks, and it is still not causal.

The mission-level test is the one that matters. If mass caused the score, the missions that physically punish mass should correlate hardest: Delivery over up to a kilometre and Autonomy over 40 minutes of terrain. They do not.

Equipment Servicing is 100 m of flat travel and dexterous work, the least mass-sensitive mission in the set, and it correlates as strongly as the total. That ordering is what a confounder looks like: heavy teams are not heavy because of the mission, they are heavy because their design did not converge, and the same failure costs points everywhere.

The within-team record settles the causal question. UIU went from 49.8 kg to 47.5 kg between 2022 and 2026, a 2.3 kg cut, and gained 164 points. West Virginia cut 20 kg between 2022 and 2023 and gained 157. Northeastern cut about 5 kg and lost 12. BRACU added 2 kg and gained 30. Mass change explains none of those four outcomes S-URC-RESULTS.

The cap is a constraint, not a target

The lightest configuration in the record is also the only far-below-cap winner: West Virginia’s Wanderer at 33.0 kg including a 5-DoF arm, which took 425.35 points in 2023. The team stated the 20 kg reduction came from a fabrication decision, a semi-monocoque sheet-metal chassis and composite wheels, not from a diet S-WVU-SAR2023.

At the other end, three different teams publish exactly 50.0 kg, all of them in the 2022–2026 window. BRACU’s 2026 Taurus is at the limit, Toronto MetRobotics’ 2026 Ingenuity is at the limit, and MIST’s 2025 Aurora X is reported at the limit. The mean of 47.9 kg is not a target that teams chose; it is the average of a distribution squeezed against a ceiling.

One measurement deserves a warning. MIST’s 2021 Phoenix is the only judge-weighed mass in the record, read aloud at 42.1 kg on the official stream, while the team’s own card for the same machine says 45 kg S-MIST-VURC2021 S-MIST-SITE-ROVERS. The judge’s number is 2.9 kg lighter than the team’s. Self-reported masses are directionally useful and not measurements.

The mass and power register

The values on this page