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Offworld’s Prospector 1 mission to demonstrate ISRU on the Moon

Concept illustration of Offworld’s Prospector 1 Mobile Excavator. Credits: Dallas Bienhoff / Offworld, Inc.

At the intersection of AI, swarm robotics and mining technology lies the key to sustainable, affordable space development. Offworld, Inc. is on the cutting edge of this frontier with their suite of diverse robot species that when coordinated with collective intelligence, will enable sustainable in situ resource utilization (ISRU) thereby lowering the cost of establishing settlements on the Moon and beyond, while kickstarting a thriving off Earth economy. In a presentation to the Future In-Space Operations (FISO) Telecon on July 24, Space Systems Architect Dallas Bienhoff described Offworld’s plans for an ambitious demonstration mission called Prospector 1.

In April 2023, OffWorld Europe entered into an agreement with the Luxembourg Space Agency to collaborate on a Lunar ISRU exploration program commissioned by the European Space Agency. The multi-year initiative will develop a processing system focused on harvesting and utilizing lunar ice resources. The program will develop a Lunar Processing Module (LPM) to be integrated into a mobile excavator that will be launched to Moon’s south pole on the Prospector 1 mission currently scheduled for late 2027. The goal of Prospector 1 is to demonstrate the capability of processing icy lunar regolith to produce oxygen and hydrogen. The LPM when loaded with icy regolith will process the lunar soil to extract water, then via electrolysis produce oxygen and hydrogen. The module’s hopper is designed to receive up to 50 kg of regolith and batch process 2.5kg/hour. The unit will be housed on a mobile excavator massed at 2500 kg. Offworld has already completed TRL4 testing on the LPM in their Luxembourg office.

Offworld is evaluating several suppliers for delivery of their payload to the Moon. These include Blue Origin’s Blue Moon Mark 1 Lander, Astrobotic’s Griffin, Intuitive Machines NOVA-D and the SpaceX Starship.

The company is exploring a variety of options for generation of power for the mission. Of course landers provide some minimal power but not nearly enough for processing lunar regolith. One promising system under consideration is the Vertical Solar Array Technology (VSAT) under development by Astorbotic which will provide 10kw of power (only in sunlight). But wait, there’s more! Astrobotic announced this month that they were just awarded a Small Business Innovation Research (SBIR) award by NASA to develop a larger version of the array called VSAT-XL capable of delivering 50kw. Designed to track the sun, VSAT is ideal for location at the lunar south pole where the sun’s rays are at very low elevation and provide semi-permanent illumination on the rims of permanently shadowed craters.

Comparison of relative sizes of the two VSAT solar arrays. Credit: Astrobotic

Another innovative alternative is a power source called the Nuclear Thermionic Avalanche Cell (NTAC ) under development by Tamer Space, a company providing a range of power and construction resources for settlements on the Moon, the Cislunar economy and sustainable pioneering of Mars. The device is an electrical generator that converts nuclear gamma-ray photons directly to electric power in a compact, reliable package with high power density capable of long-life operation without refueling. NTAC can provide higher power levels (e.g. starting at 100kw) and is not dependent on the sun to enable operations through the lunar night should Offworld elect to locate their facility far from the Moon’s poles or in permanently shadowed regions. Tamer described their technology at the 2023 Space Resources Roundtable

Image of a research prototype of the Nuclear Thermionic Avalanche Cell: Credit: Tamer Space

After Propector 1, Offworld’s follow on plans envision a second Prospector 2 to be launched in the 2029 timeframe. This mission will ramp up capability to include multiple robot species such as an excavator, hauler, and processor. In addition, liquefaction will be added to the process stream (not just gaseous products) and pilot plant capabilities will be demonstrated to reduce risk for the next mission. In 2031, a formal pilot plant will be established with multiple excavators and haulers. The facility will have a fixed processing plant and storage facilities capable of producing tons of water, oxygen, and hydrogen. By the end of 2034, OffWorld plans to launch an industrial scale ISRU plant with output of 100s of tons of volatiles, elements and bulk regolith per year.

Bienhoff said at the conclusion of his presentation that Offworld’s long term vision for lunar operations include: “Industrial scale ISRU, 10s – 100s of tons of product per year – by product [I mean] that’s processed regolith, that’s oxygen, that’s hydrogen, that’s water, that’s perhaps metals. We plan to monetize or use every gram we excavate. That’s a tall order, but in order to have a thriving lunar community, we need to produce as much as we can on the Moon, for the Moon, before we think about exporting from the Moon.”

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South Korea goes for space-based solar power

Conceptual illustration depicting the design features of a Korean Space Solar Power Satellite (K-SSPS) Credits: Joon-Min Choi, Su-Jin Choi, Sang-Hwa Yi via Creative Commons License CC by 4.0

Researchers from the Korea Aerospace Research Institute (KARI) and the Korea Electrotechnology Research Institute (KERI) describe a concept for a Korean Space Solar Power Satellite in a new publication called the Journal of Space Solar Power and Wireless Transmission. Dubbed K-SSPS, its components would be launched with reusable rockets, robotically assembled and tested in LEO, then boosted to geostationary orbit (GEO) using solar electric thrusters powered by its own solar cell array.

The baseline conceptual design for K-SSPS provides 2GW of delivered power to the ground collected by a 4km diameter rectenna located in the Demilitarized Zone. There is sufficient space in this region for 60 rectennas of this size for a total collected power of 120 GW. In terms of electricity generation, such a system would provide a terawatt-hour of electricity per year which exceeds South Korea’s electricity consumption in 2021.

This study also addresses disposal of the system after its useful life estimated to be about three decades, Since such massive systems spanning an area measuring several square kilometers would present a rather large cross section increasing the risk of collision with other decommissioned satellites in the usual graveyard orbit located 235 km above GEO, the authors propose a novel but controversial approach: controlled crash landing the spent satellite in a safe zone on the far side of the Moon. This would enable future colonies on the Moon to harvest these valuable Earth-sourced materials from the impact zone, recycling them into useful commodities to help sustain lunar operations. Care would have to be taken to ensure that the structure is guided to a designated area far from established infrastructure, most of which (if not all) would be located on the near side facing Earth. Not considered in the study was recycling and/or repurposing the K-SSPS materials in space using material processing technology like Cislunar Industries’ Modular Space Foundry (previously Microspace Foundry).

South Korea’s space agency, the Korea Aerospace Research Institute (KARI), has set a goal of a test system deployment in LEO by 2040, with a full scale system in GEO by 2050. Since this effort will take considerable development time and significant financial investment, KARI plans a small-scale two-satellite pilot system demonstration in LEO within the next decade to validate the wireless power transmission technology and the deployment mechanisms. The pilot system, which was described in a paper presented at the 73rd International Astronautical Congress in September 2022, will be placed in a sun synchronous orbit and features a solar panel equipped antenna array beaming power to a receiver satellite 100m away, in a sun synchronous orbit.

Diagram depicting the operational concepts planned over the mission life of the KARI pilot space solar power demonstration. Credits: Joon-Min Choi, Su-Jin Choi, Sang-Hwa Yi via Creative Commons License CC by 4.0

KARI and KIRI have described their case studies on a space solar power program as a renewable energy option for Korea to help address global efforts to achieve net zero greenhouse gas emissions by 2050. This paper summarizes their concept design for a 2GW space solar satellite highlighting gaps in the economic and technological knowledge needed for success, proposed a responsible and sustainable disposal method, and outlined an achievable architecture for a near term pilot demonstration within a decade. Korea joins other global development efforts that SSP has been following with their own unique approach to space-based solar power (SBSP).

However, doubters have been surfacing recently highlighting the significant engineering and economic challenges that need to be addressed for SBSP to be competitive with ground-based renewable energy sources and backup storage systems, the technology of which are rapidly developing and improving. One skeptic, former European Space Agency engineer Henri Barde, published an article in IEEE Spectrum arguing that among other things, designers will have a significant challenge shaping and aiming the microwave beam of a kilometer-scale phased array antennae. In his opinion, this and other engineering obstacles will not be solved until fusion energy will be commercially available. In a rebuttal on LinkedIn, CEO of SBSP startup Virtus Solis John Bucknell responded that his company has proprietary software that can simulate greater than 2km transmission apertures and that SBSP is in the engineering phase while fusion is still in R&D, the complexity of which makes capital and operating costs a big unknown for commercialization.

NASA has yet again kicked the can down the road, claiming in their most recent study that expected greenhouse gas emissions and the cost of space hardware for current design options will be on a par with existing renewable electricity technologies and therefore recommends further study to close several technology gaps for SBSP to make economic sense. The next few years will be critical for engineering testing, not only for Korea’s pilot satellite, but Virtus Solis‘s in-space plans and Northrup Grumman’s end-to-end test in 2025 of their Space Solar Power Incremental Demonstrations and Research prototype system. Once in-space prototype testing demonstrates sufficient feasibility to retire technical risks, venture capital investors may feel comfortable funding subsequent operational phases toward profitable commercialization.