CubeRover

NASA/Glenn Benson. Public domain (NASA / US government work).

Overview

CubeRover is a class of small lunar rovers built by Astrobotic Technology of Pittsburgh. It applies the CubeSat unit convention to surface mobility: one U is a 10 x 10 x 10 cm payload volume carrying 1 kg, and the vehicle is offered in 2U, 4U and 6U sizes that scale volume and payload capacity while reusing the same power, thermal, structural, avionics and software systems [1]. Astrobotic sells it as a service rather than as hardware.

Development was funded through NASA Small Business Innovation Research and a $2 million Tipping Point award made in September 2019 [3], [4].

Every vehicle number below comes from Astrobotic’s own specification material [1], [2]. Where the manufacturer’s documents disagree, both values are given. Test results are from NASA and manufacturer accounts of the same NASA KSC campaigns [3], [4]. No peer-reviewed engineering description of the platform has been published.

Specifications

Parameter	2U	4U	6U
Rover mass	4.6 kg	8 kg	10.6 kg
Payload capacity	up to 2 kg	up to 4 kg	up to 6 kg
Guaranteed payload envelope	20 x 10 x 10 cm	20 x 20 x 10 cm	30 x 20 x 10 cm
Additional internal volume	2100 cm3	3900 cm3	5700 cm3
Additional external volume	910 cm3	1768 cm3	2625 cm3
Payload energy allocation	100 Wh+	150 Wh+	200 Wh+

Manufacturer figures, from [1].

Parameters common to all three sizes:

Parameter	Value	Source
Payload power bus	28 V DC	manufacturer [1]
Payload thermal environment	-20 to +60 degrees C
Payload wired interface	RS-422
Payload data allocation	10 kbps per kilogram of payload
Payload wireless standard	802.11n WLAN
Payload data storage	32 Gb or more
Nominal speed	4 cm/s
Top speed	10 cm/s	manufacturer [2]
Slope limit	30 degrees
Obstacle diameter	nearly 15 cm

The two speeds come from different manufacturer documents and are not related to each other in either: 4 cm/s is the nominal speed on the datasheet [1], 10 cm/s the top speed on the product page [2].

Mission profile

No CubeRover has been assigned to a flight. The datasheet states support for several lander configurations, and a design mission of 8 Earth days [1], covering multiple kilometers in a single lunar day [2].

Iris, flown on Peregrine Mission One in January 2024 [1], originated in the same Carnegie Mellon CubeRover work but is a separate vehicle.

Mobility

Four aluminum wheels, each independently actuated, with dust covers and seals [2]. There is no rocker or bogie in the published description, so the vehicle is a rigid four-wheel skid-steer platform, which is consistent with the point-turn testing performed [4].

Mobility characterization was run in the Granular Mechanics and Regolith Operations laboratory regolith bin at NASA KSC Swamp Works, which holds about 120 tons of lunar regolith simulant [3]. Over 150 mobility tests were performed with 11 sets of wheels [4]. Drawbar pull, slope and point-turn data were taken from the rover’s own sensors. Some wheel sets climbed 30 degree slopes and others turned in deep regolith, and two sets exceeded the test expectations; a second campaign on 30 June 2022 used a mass-offloaded vehicle in the same bin to represent mobility at lunar gravity [4].

The 30 degree slope figure quoted as a vehicle capability [2] is the best result across 11 wheel sets rather than a qualified vehicle limit [4].

Power and energy

The vehicle is solar powered. Array power and battery capacity are not published; what is published is the energy made available to the payload, 100 Wh or more on a 2U and 200 Wh or more on a 6U [1].

The baseline vehicle does not survive the lunar night: mission duration is 8 Earth days [1]. Night survival is offered as a customization, and a separate Tipping Point contract funds wireless charging intended to let CubeRover endure the night [2].

Thermal

The thermal design is not published beyond the service it provides. All CubeRover sizes share the same thermal system [1], and the payload thermal environment provided is -20 to +60 degrees C. No radiator area, insulation stackup or vehicle operating temperature range is published.

Compute and avionics

All CubeRover sizes share the same avionics and software systems [1]. No processor part, memory, radiation tolerance approach or software framework is published.

Autonomy

Navigation is teleoperated with a visual-inertial system, using wide angle cameras front and rear [2]. An onboard safeguard returns the rover automatically to its last known position. No stereo baseline is described, so depth would have to come from motion.

Communications

The published payload wireless standard is 802.11n WLAN, the payload data allocation is 10 kbps per kilogram of payload, and onboard storage is 32 Gb or more [1]. No link budget, radio part or direct-to-Earth capability is stated.

Payload and instruments

CubeRover carries no instruments of its own; the payload is the customer’s. Top and bottom mounted payloads are both supported [1]. Non-standard services are stated to be available on request.

Modes of operation

The datasheet describes the platform as customizable to mission needs, including lunar night survival and missions to craters and permanently shadowed regions [1], but no deployment sequence or operating mode set is given.

Technologies developed

The transferable product is the interface standard rather than the vehicle: a CubeSat-style unit convention for surface mobility, with a published specification fixing envelope, 28 V bus, RS-422, WiFi, data rate per kilogram and thermal environment, so that a payload developer sizes against a standard rather than against a bespoke rover [1]. The second is the wheel test dataset from NASA KSC: drawbar pull, slope and point-turn measurements across 11 wheel sets in 120 tons of simulant, at both Earth gravity and mass-offloaded to represent lunar gravity [3], [4].