Our nation is poised to return to the lunar surface for the first time since the Apollo program ended 50 years ago. We plan to stay longer this time, venture farther, and probe deeper than ever before. Like early pioneers on Earth, it will require us to learn how to use the resources at hand or to “live off the land” on the Moon. And the most critical resource of all is power.
To open the Moon to continuous multi-year human and robotic operation, Astrobotic – a Pittsburgh-based tech company specializing in developing lunar innovations – is developing LunaGrid™ — a commercial power system for the surface of the Moon. LunaGrid is a complete solar and surface power generation and distribution service that survives the lunar night and delivers continuous power to lunar surface assets for multi-year operations.
At its most basic level, LunaGrid will consist of power-generating stations, or nodes, connected by physical power transmission cables laid across the lunar surface. Relative to other power transmission methods, such as power beaming, power cables provide the most reliable, lowest loss means of power transfer, with transmission efficiencies approaching 97 percent. Cables are also a safer method of power transfer in many regards since power beaming could bathe astronauts’ bodies with harmful radiated power.
The power generators at LunaGrid’s nodes may include lunar landers with integrated solar arrays, stand-alone Vertical Solar Array Technology (VSAT) stations, Horizontal Solar Array Technology (HSAT) stations, and Fission Surface Power (FSP) stations. VSATs are optimized for the low sun angles near the lunar poles and HSATs for the high sun angles near the lunar equator, while FSPs, which utilize nuclear power, are location-agnostic.
Astrobotic is currently executing a contract from NASA’s Space Technology Mission Directorate (STMD) Game Changing Development (GCD) program to build a full-scale VSAT prototype and verify its operation in a thermal-vacuum test chamber on Earth. It has also partnered with another Pittsburgh energy innovator, Westinghouse, to develop FSP systems for the Moon through a separately funded NASA GCD contract.
Astrobotic’s VSAT uses innovative Roll Out Solar Arrays (ROSAs), large, flexible solar panels that can be rolled up and compactly stowed for transport and then rolled back out once on the Moon. Their ability to be stowed and redeployed makes ROSAs easier and cheaper to fit and fly on rockets and landers. LunaGrid will showcase the first use of ROSAs on the Moon. On VSAT, the ROSA is, in turn, mounted atop a Lunar Infrastructure Trailer (LIT), a mobile base that can transport ROSAs to strategic locations on the lunar surface, including sites near assets requiring power or sites that experience higher fractions of solar illumination throughout the year than others.
To deploy LunaGrid’s power transmission lines, Astrobotic will employ its fleet of rovers, including Astrobotic’s smaller CubeRover, larger Polaris rover, and the VSAT LIT trailer itself. The company is currently developing and testing advanced cable stowage, deployment, and management systems, such as spools and guides for integration onto these rovers. These systems are designed to deploy the cable as the rover drives to avoid dragging or snagging the cable on the abrasive lunar terrain. The smallest of these rovers, CubeRover, will provide “last mile” — or in this case, last 100 meters — power delivery, driving up to and transferring power to customer assets via wireless chargers. Wireless chargers are preferred because they do not require exact alignment, are immune to regolith-induced wear and tear and can be more easily integrated into existing landers and spacecraft. Astrobotic has developed the first such wireless chargers for the lunar surface and has already begun selling them to NASA and commercial customers.
For the first generation of LunaGrid, a VSAT will be integrated on a single Astrobotic lunar lander and launched to the Moon on a single rocket. Upon landing, the VSAT will egress from the lander, traverse to its operating site, deploy its power transmission cable along the way, and begin generating solar power. Power can then be transferred between the VSAT and lander — the first two nodes in the lunar power grid — and to customer assets via tethered CubeRovers with wireless chargers. Astrobotic plans to begin deploying and demonstrating LunaGrid elements as early as 2026 with the goal of commissioning the first seeds of LunaGrid as early as 2028 at the lunar south pole.
This article was written by Dr. Thomas Oberst, Director of Proposal Development, Astrobotic (Pittsburgh, PA). For more information, visit www.astrobotic.com .