Polaris Demonstrates Excavation at NASA Glenn
Polaris is an excavating rover intended to prospect for water ice and other trapped volatiles at the permanently shadowed poles of the Moon. While designed to accommodate a variety of payloads, Polaris is currently fitted with hardware to excavate and transport regolith for mission scenarios involving in-situ resource utilization.
On 5/8/13, an Astrobotic team headed by Chris Skonieczny traveled to NASA Glenn Research Center to demonstrate Polaris’ mobility and excavating ability in lunar regolith simulant. The nominal goal was to dig one metric ton of lunar regolith simulant in one hour. This was the culminating demonstration for a Phase II SBIR contract for Lightweight Robotic Excavation.
Polaris’ testing was conducted at the NASA Glenn SLOPE facility, which provided the means to test mobility and excavating ability in the lunar regolith simulant GRC-1. Polaris met all mobility requirements: reaching a speed of 40 cm/ sec, climbing slopes up to 15 degrees, and traversing a variety of obstacles up to 20cm in height.
Polaris was equally successful at meeting the excavation goals and requirements: digging depths more than 20cm deep, hauling more than 80kg of regolith at one time, and being unaffected by 30cm and smaller rocks. During a continuous excavation test, Polaris excavated, transported, and dumped over 1000kg of lunar simulant in under one hour.
Next for Polaris is to test mobility and excavation performance in a simulated Moon gravity environment. Testing will occur at Astrobotic’s soon to completed gravity offload simulator. While terrestrial excavating machines rely on Earth’s gravity to produce large cutting forces through the soil with a single bucket, Polaris’ continuous excavating system uses multiple cutting buckets that each take a small bite of regolith. This requires lower digging forces, making excavation easier and more productive in low gravity conditions.