Terramechanics did not begin in space — it grew out of terrestrial off-road, military, and agricultural vehicle engineering, and that is exactly where it pays off again. The same simulation that sized Astroport’s lunar vehicles applies directly to mining and earthmoving: predicting traction, sinkage, gradeability, and haul-cycle energy for heavy fleets on soft or graded ground, so operators can size equipment before committing capital. It extends to heavy off-road transport in sectors such as oil and gas, wherever vehicles must move reliably over difficult terrain.

The specific unknowns were the ones that decide whether a surface vehicle succeeds or strands itself:

• Wheel sinkage and rutting: How deep the wheels settle into regolith, and how that changes from an empty to a fully loaded vehicle.
• Motion resistance and drawbar pull: The usable force a vehicle generates after overcoming its own rolling resistance — whether the vehicles can move at all and, for the tool-carrying machine, whether it can push or pull implements through the soil.
• Gradeability under load: Whether a loaded vehicle can still climb the slopes the mission demands.
• Drive torque, power, and energy per distance: The “mileage” that determines how much battery and charging infrastructure the mission must provide.

These were hard to pin down: the hauler’s mass changes dramatically between empty and fully loaded, and the heritage data that exists is scattered across decades of separate programs. Without a model that ties it together under lunar conditions, every design choice was a guess.

The risk cut both ways. Oversize the vehicles and their motors, and Astroport wastes launch mass and power it cannot spare on the Moon. Undersize them, and a vehicle can bog down, fail to climb, or strand itself — compromising not just site preparation but every mission that depends on a prepared surface.

Solution

Validated terramechanics, from Apollo to Astroport

Across Astroport’s STTR phase, SoftServe’s Robotics and Advanced Automation team ran the terramechanics simulation with one clear goal: turn two notional vehicle concepts into designs backed by numbers.

The method has a long track record in off-world vehicle design. Its simulations use semi-empirical terramechanics in the Bekker-Wong-Reece tradition — a framework built on decades of off-road, military, and agricultural vehicle engineering. The same modeling tradition informed the Apollo Lunar Roving Vehicle, China's Yutu lunar rovers, the Zhurong Mars rover, and Europe's ExoMars rover. That heritage matters: the predictions rest on models calibrated against real wheel-and-soil test data and proven across decades of rover design, rather than on first-principles guesswork — with the lunar regolith parameters themselves treated as the key modeled input to be refined as ground-truth data improves.

The team built parametric models of both vehicles in the site-preparation architecture: the Astroport Transport Platform (ATP), a baseline hauler design, and Astrolab’s Flexible Logistics and Exploration rover, FLEX. “Parametric” is the key word — the models let Astroport step through ranges of vehicle geometry, wheel dimensions, wheel stiffness, and load conditions, and see immediately how each choice affects performance.

For every configuration, the simulations predicted the quantities that decide whether a design works:

• Wheel sinkage and rut depth
• Motion resistance and drawbar pull versus wheel slip
• Gradeability, or slope-climbing ability under load
• Drive torque
• Drive power and energy consumption per distance traveled
• All of it was computed under lunar gravity and the regolith-interaction parameters defined for the project, so the outputs reflect the environment the vehicles will actually face.

The team implemented the models in OpenModelica with Python, and used NVIDIA Isaac Sim to visualize the rover in its operating environment. The result was less a single answer than a design instrument: a way for Astroport to choose wheel sizing and motorization on a rational basis, confirm whether existing actuators are adequate, and — critically — translate vehicle performance into the power and charging infrastructure the mission must carry.

Value Delivered

Designs validated, sized, and proven

The headline result is the one Astroport needed most: the simulations confirmed both baseline vehicle designs are suitable for their site-preparation architecture — including energy consumption and traction. Astroport can move forward on its mobility and power architecture having de-risked it before committing any hardware.

What the modeling established:

• Power budget: A model of the hauler’s electrical demand across its full operating envelope — from steady level hauling to worst-case loaded slope climbs — gave Astroport a complete power budget confirming it stays within what the platform can supply.
• Drivetrain: The analysis confirmed that the existing actuators are correctly sized across the operating range, so the drivetrain does not need a costly redesign.
• Battery and charging: By predicting how much energy the vehicles consume as they work, the modeling let Astroport size batteries and place charging stations across the site — turning an open power question into a concrete infrastructure plan for its CONOPS.
• General mobility machine: The analysis confirmed the mobility machine generates more than enough drawbar pull to drive several excavation tools through regolith.

Each of these findings is the line between a rover that climbs the grade and one that strands itself, and between a power system Astroport can afford to launch and one it can’t. Together, the work turned two unproven concepts into a quantified design envelope — wheel sizing, motorization, traction, and power infrastructure — that Astroport can build against.