VPR 21 – Advanced Excavation Robotic System for Lunar Regolith Mining (NASA RASSOR Architecture) and potential application today

Research & Design: Viktor Vildović, Victor Production R&D Division

Material: carbon fiber, welded titanium sheets, modified ball bearings

Field: Space Robotics, Extraterrestrial Mining, Mechanical Engineering, Mechatronics

Keywords: NASA RASSOR, lunar regolith mining, space robotics, bucket drum design, mass optimization, carbon fiber, titanium, anti-jamming mechanism.

1. Abstract

Mining on the Moon is one of the greatest challenges in space engineering. Operating robots must collect and move abrasive lunar regolith in microgravity conditions, with minimal dust dispersion, strict mass constraints, and high energy efficiency requirements. This paper presents VPR 21 – an innovative bucket drum design developed for the NASA RASSOR (Regolith Advanced Surface Systems Operations Robot) system. The concept introduces mechanical innovations such as an active anti-jamming rotating wall, extremely fast unloading (under 3 seconds), and a kinetic self-cleaning function, dramatically increasing the efficiency of extraterrestrial mining operations.

2. The Engineering Challenge: Mining in an Abrasive Vacuum

Conventional excavation systems rely on the heavy mass of the machine to generate the penetration force into the soil. On the Moon (where gravity is 1/6th of Earth's), this is not viable. RASSOR solves this problem with counter-rotating bucket drums on both ends of the robot, effectively canceling out the lifting force.
However, the critical problems of standard bucket drum systems are:

• Jamming of larger lunar rocks at the bucket inlet.
• Adhesion of abrasive dust that hinders unloading and degrades rotational components.
• Excessive power consumption during prolonged unloading phases.

3. VPR 21 Architecture and Performance Optimization

The VPR 21 design directly addresses these issues through rigorous geometric optimization and the application of advanced materials. The structure utilizes bonded carbon fibers, precision-welded titanium sheets, and modified ball bearings to maximize the volume-to-weight ratio.
Comparative Specifications (Requirement vs. VPR 21 Achievement):

	NASA (RASSOR) Bucket Drum Design Challenge	Zahtev kon. │	VPR 21 dizajn
1.	Maximum bucket drum mass:	≤ 5000 g	= 4997 g
2.	Maximum bucket drum diameter:	≤ 450 mm	= 450 mm
3.	Maximum bucket drum length:	≤ 360 mm	= 300 mm (Kompaktniji dizajn)
4.	Minimum volume of regolith captured:	≥ 17,6 l	= 24,09 l (povećanje kapaciteta 36%)
5.	Maximum total scoops width engaged at any given time:	≤ 175 mm	= 147 mm
6.	Design fill ratio higher than:	≥ 50 %	= 50.5 %

4. Operational Kinematics and Innovations

The bucket drums and the inner collection bucket are independently connected to a modified reduction gear on the RASSOR arm, allowing independent or simultaneous rotation.
     4.1. Loading Phase and "Anti-jamming" Mechanism:
Upon contact with the surface, the scoops rotate at the bottom position and fill with regolith. As they lift to the top position, gravity forces the captured regolith into the upright inner bucket. At this stage, the innovation occurs: a movable rotating wall automatically clears larger rocks right at the inlet, preventing mechanism blockage.
     4.2. Kinetic Self-Cleaning:
At the exit of the loading position, the raised scoop closes by striking the outer wall of the rotating assembly. This calculated mechanical impact generates targeted vibrations that effectively shake off adhered regolith, keeping the system clean without the need for additional, energy-consuming actuators.
     4.3. Fast Unloading (Speed < 3s):
Thanks to the specific geometry, the bucket drums and the inner bucket rotate simultaneously and stop in a position where the opening faces downward. With a further 90-degree rotation of the scoops, the entire regolith payload exits the bucket. This maneuver reduces unloading time to under 3 seconds, drastically conserving the limited electrical energy reserves on the lunar rover.

5. The Manufacturing Vision of Victor Production R&D

VPR 21 is not merely a theoretical CAD model, but a potential product for our manufacturing and engineering capabilities. The integration of carbon fiber with complex titanium structures and the fabrication of specialized transmission mechanisms (reduction gears) are integral parts of our daily R&D process.
Systems like VPR 21 — which demand zero - tolerance for failure, high structural endurance, and operational autonomy — have broad applications not only in the space industry but also in terrestrial applications in extreme environments (mining, radiation - contaminated areas, underwater robotics).

6. Call for Engineering Collaboration

If your institution or company is developing mechatronic systems for extreme operating conditions, Victor Production offers the capabilities to translate your concepts from theoretical simulation into fully functional, tactically optimized hardware.

Schedule an engineering consultation for your R&D project