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Sustainable space commerce and settlement

Artist impression of a sustainable settlement on the Moon. Credits: ESA – CC BY-SA IGO 3.0

Dylan Taylor of Voyager Space Holdings recently wrote an article in The Space Review on sustainable space manufacturing. He makes a convincing case that long-duration space missions and eventual human expansion throughout the solar system will require radical changes in the way we design, manufacture, repair and maintain space assets to ensure longevity. In addition, the cost of lifting materials out of Earth’s deep gravity well will drive sustainable technologies such as additive manufacturing in space and in situ resource utilization to reduce the mass of materials needed to be launched off our planet to support space infrastructure. In-space recycling and reuse technologies will also be needed along with robotic manufacturing, self-reparability and eventually, self-replicating machines.

But there is more to the philosophy of sustainability and its impact on the future of space activities. According to the Secure World Foundation (SWF), sustainability is essential for “Ensuring that all humanity can continue to use outer space for peaceful purposes and socioeconomic benefit now and in the long term. This will require international cooperation, discussion, and agreements designed to ensure that outer space is safe, secure and peaceful.” Much of the discussion centers around the problem of orbital debris, radio frequency interference, and accidental or irresponsible actions by space actors. SWF is active in facilitating dialog among stakeholders and international cooperation.

The National Science and Technology Council released a report in January called the National Orbital Debris Research and Development Plan. To address the issue, there are several companies about to start operations in LEO to deal with the orbital debris or in-orbit servicing. Japan based Astroscale just launched a demonstration mission of their End-of-Life Services by Astroscale (ELSA) platform to prove the technology of capturing and deorbiting satellites that have reached their end of life or other inert orbital debris.

Image of the Astroscales ELSA-d mission showing the larger servicer spacecraft releasing and preparing to dock with a “client” in a series of technical demonstrations, proving the capability to find and dock with defunct satellites and other debris. Credits Astroscale.

Even financial services and investment houses like Morgan Stanley are pushing for sustainability to reduce the risks to potential benefits emerging from the Newspace economy such as remote sensing to support food security, greenhouse gas monitoring, and renewable energy not to mention internet access for billions of people.

Sustainable operations on the Moon are being studied by several groups as the impact of exploration and development of Earth’s natural satellite is considered. Lunar dust when kicked up by rocket exhaust plumes could create hazards to space actor’s assets as well as Apollo heritage sites. SWF, along with For All Moonkind, the Open Lunar Foundation, the MIT Space Exploration Initiative and Arizona State University have teamed up on a project called the Moon Dialogs to advance interdisciplinary lunar policy directions on the mitigation of the lunar dust problem and to shape governance and coordination mechanisms among stakeholders on the lunar surface. SSP’s take on lunar dust mitigation was covered last July.

These few examples just scratch the surface. NASA, ESA and the UN Office for Outer Space Affairs have initiatives to foster sustainability in space. Humanity will need a collaborative approach where public and private stakeholders work together to ensure that the infrastructure to support near term commercial activities in space and eventual space settlement is both durable and self-sustaining.

The long-term sustainability of space. Credits: ESA / UNOOSA
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Stability and limitations of environmental control and life support systems for space habitats

Image of Biosphere 2, a research facility to support the development of computer models that simulate the biological, physical and chemical processes to predict ecosystem response to environmental change. Credits: Biosphere 2 / University of Arizona

Once cheap access to space is realized, probably the most important technological challenge for permanent space settlements behind radiation protection and artificial gravity is a robust environmental control and life support system (ECLSS). Such a system needs to be reliably stable over long duration space missions, and eventually will need to demonstrate closure for permanent outposts on the Moon, Mars or in free space. In his thesis for a Master of Science Degree in Space Studies, Curt Holmer defines the stability of the complex web of interactions between biological, physical and chemical processes in an ECLSS and examines the early warning signs of critical transitions between systems so that appropriate mitigations can be taken before catastrophic failure occurs.

Holmer mathematically modeled the stability of an ECLSS as it is linked to the degree of closure and the complexity of the ecosystem and then validated it against actual results as demonstrated by NASA’s Lunar-Mars Life Support Test Project (LMLSTP), the first autonomous ECLSS chamber study designed by NASA to evaluate regenerative life support systems with human crews. The research concluded that current computer simulations are now capable of modeling real world experiments while duplicating actual results, but refinement of the models is key for continuous iteration and innovation of designs of ECLSS toward safe and permanent space habitats.

This research will be critical for establishing space settlements especially with respect to how much consumables are needed as “buffers” in a closed, or semi-closed life support system, when the model’s metrics indicate they are needed to mitigate instabilities. Such instabilities were encountered during the first test runs of Biosphere 2 in the early 1990s.

As SpaceX races to build a colony on Mars, they will need this type of tool to help plan the life support system. Holmer believes that completely closed life support systems for relatively large long term settlements are at least 15 to 20 years away. That means that SpaceX will need to resupply materials and consumables due to losses in their initial outpost who’s life support system in all probability will not be completely closed during the early phases of the project over the next decade. Even SpaceX cannot reduce launch costs low enough to make long term resupply economically viable. They will eventually want to drive toward a fully self sustaining ECLSS. That said, depending on how the company funds its initiatives and sets up it’s supply chains, they may not need a completely closed system for quite some time.

Of course there are sources of many of the consumables on Mars that could support a colony but not all the elements critical for ecosystems, such as nitrogen, are abundant there. There are sources of some consumables outside the Earth’s gravity well which could lower transportation costs and extend the timeline needed for complete closure. SSP covered the SHEPHERD asteroid retrieval concept in which icy planetesimals, some containing nitrogen and other volatiles needed for life support, could be harvested from the asteroid belt and transported to Mars as a supply of consumables for surface operations. TransAstra Corporation is already working on their Asteroid Provided In-situ Supplies family of flight systems that could help build the infrastructure needed for this element of the ecosystem. It may be a race between development of the competing technologies of a self-sustaining ECLSS vs. practical asteroid mining. The bigger question is if humans can thrive long term on the surface of Mars under .38G gravity. In the next century, O’Neill type colonies, perhaps near a rich source of nitrogen such as Ceres, may be the answer to where safe, long term space settlements with robust ECLSS habitats under 1G will be located.

Curt Holmer appeared recently on the The Space Show discussing his research. I called the show and asked if he had used his modeling to analyze the stability of ecosystems sized for an O’Neill-type colony. He said he had only studied habitats up to the size of the International Space Station, but that it was theoretically possible to analyze this larger ecosystem. He said he would like to pursue further studies of this nature in the future.

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NASA’s measurement plan for a lunar water reserve

Diagram depicting NASA’s Lunar Water ISRU Measurement Study (LWIMS). Credits: NASA

NASA just published a Technical Memorandum on its Lunar Water ISRU Measurement Study (LWIMS). The TM describes the establishment of a measurement plan for identification and characterization of a water reserve on the Moon. This program would support the Artemis program to achieve a sustainable lunar presence by 2028.

Three primary data inputs feed information into the system. First, predictive modeling provides a ‘water favorability’ index to map out locations on the Moon with water ice potential. This algorithm is fed data by orbital measurements providing information on a regional scale. It is critical that this orbital data is interpreted properly for water-favorable sites on the Moon. To ensure accuracy, lunar landers will take surface measurements in a series of three phases: mobile reconnaissance for validation of the predictive model, focused exploratory missions to verify water’s presence and final reserve mapping to inform an ISRU ice mining plant by 2028.

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Eta Space snags $27 million Tipping Point award to study space based cryogenic propellant depot technologies

Artist rendering of LOXSAT 1, a demonstrator satellite for a cryogenic oxygen fluid management system. Credits: Eta Space

A small Florida Space Coast start up founded by NASA employees called Eta Space was just awarded a 2020 NASA Space Technology Mission Directorate “Tipping Point” contract to develop the first low Earth orbit cryogenic propellant depot. Management of cryogenic fuels is a key technology for storing propellent in space, which will be a component of a transportation infrastructure supported by in situ resource utilization such as ice mining on the moon for processing into rocket fuel. A key focus of the work by Eta Space will be standardization of equipment interfaces allowing multiple customers to tap into storage capability on orbit.

Eta Space’s LOXSAT 1 mission concept will test a range of cryogenic fuel management processes in space over 9 months specific to liquid oxygen management. LOX is a common oxidizer used across multiple propellant systems by several launch providers and is the heaviest cryogenic fluid needed by most customers.

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Intuitive Machine’s PRIME-1 ice mining drill to be delivered to the Moon by 2022

Illustration of Intuitive Machines’ Lunar Lander. Credits: Intuitive Machines

As part of the Commercial Lunar Payload Services (CLPS) initiative, NASA has selected Intuitive Machines to deliver ice harvesting equipment called Polar Resources Ice Mining Experiment (PRIME-1) to the Moon’s south pole. In a press release from yesterday, Intuitive stated that the instrument package includes a drill to excavate ice ladened regolith and a mass spectrometer to characterize the volatiles, the data from which will be used by the VIPER mission to follow shortly thereafter. Knowing how much water is available and how accessible it is will inform subsequent in situ resource utilization efforts needed for sustainable human outposts planned for later this decade.

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AIAA ASCENDxCo-Lab workshop identifies technology gaps for economically viable lunar settlements

Artist’s impression of a lunar settlement. Credit: ESA/Foster + Partners via universetoday.com

The 2020 virtual event sponsored by the American Institute of Aeronautics and Astronautics held in August brought together 200 space industry leaders from all over the world to discuss and respond to NASA’s ARTEMIS Plan. The event was summarized in a proceedings report that captured the group’s consensus on the technological and economic conditions needed for a sustained and economically viable lunar settlement. The attendees discussed the role of national space agencies, governments, and industry in addressing those conditions. The report defined a sustained lunar settlement as meeting the test of continuous survival and operation over time, and an economically viable settlement as one for which the long-term cost of maintenance is sustained by private capital.

When polled on the key technologies needed for a long term permanent presence on the Moon, the group identified the gaps in the chart below as those areas needing higher Technology Readiness Levels (TRL) to enable a permanent lunar settlement.

Technology areas needing further development. Credits: Jessica Todd et al.* / AIAA

The authors* then summarized the economic conditions identified at the workshop conducive to sustained lunar settlements, information needed to close the technology gaps and the roles of government space agencies as well as non-aerospace industries (e.g. healthcare, agriculture, food processing, utilities, mining and construction). _________________________________________________________________________________

* Authors of the ASCEND Ensuring Economically Viable Lunar Settlements Proceedings Report 2020 include:

Jessica Todd, Graduate Research Assistant, Aerospace Engineering in Autonomous Systems, Massachusetts Institute of Technology and the Woods Hole Oceanographic Research Institute
George Lordos, Ph.D. Candidate, Aeronautics and Astronautics, Massachusetts Institute of Technology
Becca Browder, Graduate Research Assistant, Aeronautics and Astronautics, Massachusetts Institute of Technology
Benjamin Martell, Graduate Research Assistant, Aeronautics and Astronautics, Massachusetts Institute of Technology
Cormac O’Neill, Graduate Research Assistant, Mechanical Engineering, Massachusetts Institute of Technology

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Modular habitation system for human space exploration

Diagram of modular exploration system: pressure vessel, tertiary structures, power systems, EVA, and mobility. Credits: A. Scott Howe, Phd

At the 45th International Conference on Environmental Systems, A. Scott Howe, PhD presented a paper on a novel modular system for human habitation to support planetary and space exploration. The paper addresses the design requirements including mass and volume constraints to enable a variety of missions and environments. The concept was developed as recommended by NASA’s Evolvable Mars Campaign for a compact modular system and was assumed to be launched using the Space Launch System currently in the final stages of development. Howe settled on a horizontal module as the most appropriate with a single small diameter solution for fixed-sized habitats, expandable habitats, small rover cabins and a variety of other applications for both in-space and planetary surface operations.

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Life in space

Artists rendering of the LIFE™ Habitat. Credits: Sierra Nevada Corporation

In a press release on August 10, Sierra Nevada Corporation announced it is continuing to advance it’s Large Inflatable Fabric Environment (LIFE) habitat under Phase 3 of NASA’s Next Step-2 public-private partnership to further commercial development of deep space exploration capabilities.

The company’s CEO, Fatih Ozmen, said “Our habitat design is so unlike any other that it truly demonstrates SNC’s technology ingenuity and innovation. We are excited to continue our support of human exploration in low-Earth orbit, for the Artemis lunar missions, and eventually missions to Mars, making space accessible and affordable.”

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Lava Hive: ISRU Mars habitat

Stepwise illustration of the casting process to produce the Lava Hive; (1) deposition of foundation base, (2) regolith is gathered and sintered into a flow channel, (3) molten basalt from the sand/regolith is poured into the channel and allowed to solidify, (4) the next layer of regolith is spread across, and another channel sintered, (5) layer by layer the structure is constructed, (6) loose, un-sintered regolith is excavated from the structure, revealing the completed dome. Credits Aidan Cowley, et al.*

In a paper posted on Academia.edu, the 3rd prize winner for the 2015 NASA 3D Printed Mars Habitat Centennial Challenge called Lava Hive is described by a team* of European researchers. The habitat is produced by additive manufacturing via a ‘lava-casting’ construction technique and utilizing recycled spacecraft structures. Innovations include ‘re-use’ of discarded landing vehicles as part of the central habitat, 3D printed adjacent structures connected to the central habitat and use of a novel ‘LavaCast’ process to fabricate solid structures resistant to radiation and thermal cycling.

Illustration of the Lava Hive. The central habitat core is shown with the smaller 3D printed satellite structures clustered around it. Credits: René Waclavicek, LIQUIFER Systems Group, 2015

The Lava Hive Mars settlement has a number of advantages including a modular design with the ability to expand or adapt to changing mission requirements while “living off the land” with a simple ISRU process utilizing Martian soil, thereby reducing the amount of mass that would need to be launched from Earth.

* Authors of this paper are: Aidan Cowley, Barbara Imhof, Leo Teeney, René Waclavicek, Francesco Spina, Alberto Canals, Juergen Schleppi, Pablo Lopez Soriano

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Mitigation of the risks and challenges of lunar dust

Astronaut Gene Cernan covered in Lunar dust after an EVA during the Apollo 17 mission. Credits: NASA

Catch my presentation at the Moon Society’s Lunar Development Conference that took place on July 19 and 20 in which I describe the hazards posed by lunar dust and several solutions needed for space settlement. This is definitely on the critical path for large scale operations on the moon.

There were a couple of technical glitches in the presentation, one of which was playing a simplistic animation of deploying a dust-free landing pad beneath an initial lunar lander using telerobots. You can view the animation here. Hat tip to Doug Plata and the Space Development Network for the source material used in the presentation. Many of the conference presentations are available on the Moon Society’s YouTube Channel.