One kilometer long spinning space station producing 1G of artificial gravity deployed from a single Falcon Heavy launch vehicle. Credits: Zachary Manchester, graphic by Tzipora Thompson
This year’s NASA Innovative Advance Concepts (NIAC) award winners presented their ideas in a virtual poster session last week. Zachary Manchester of Carnegie Mellon University and Jeffrey Lipton at the University of Washington have come up with a rotating habitat to produce artificial gravity. But to do this without causing severe disorientation that would result from a short radius habitat, their novel facility is one kilometer long spinning to produce 1G at both ends. Manchester and Lipton’s innovation is a deployment mechanism that leverages advances in “mechanical metamaterials” to reduce mass while increasing expansion ratios such that the structure can be squeezed into a single Falcon Heavy payload envelope but when deployed, expands to 150 times its stored configuration size. The structure can be erected autonomously and without any assembly in space.
The key enabling technologies are a combination of “handed shearing auxetics” (HSA) and branched scissor mechanisms. HSA is described in a 2018 paper in Science by Lipton and other researchers where they “…produce both compliant structures that expand while twisting and deployable structures that can rigidly lock.”
“The station can…be spun at 1-2 RPM to generate 1g artificial gravity at its ends while still maintaining a microgravity environment at its center near the spin axis, providing the crew with the flexibility of living in a 1g environment while performing some work in microgravity.”
Conceptual illustration of a Habitat Autonomous Locomotive Expandable (HALE) mobile self sustaining habitat under propulsion near a planetary destination. Credits: unknown artist via Thomas Matula
Dr. Thomas Matula, Professor at Sul Ross State University Uvalde, Texas, has developed an economically based strategy for space settlement. His plan addresses the deficiencies in many proposed visions of human expansion beyond earth, namely the missing economic and legal aspects needed for sustainable settlement of the solar system. Matula discussed his approach with David Livingston on The Space Show September 14 and in a paper entitled An Economic Based Strategy for Human Expansion into the Solar System attached to the show blog.
Astrosettlement Development Strategy (ADS) can be boiled down into a four step economically based roadmap for space settlement which could be started with minimal private funding. Each step would achieve economic success before moving on to the next level. The four levels are Earth based research, industrialization of the Moon, developing and settling the solar system and interstellar migration.
In the first step of Earth based research, Matula suggests developing a subscription based online role playing computer game with the purpose of creating a virtual simulation of a space settlement to model the social and economic aspects of communities beyond Earth. SSP has been following similar efforts already underway by Moonwards. Further research in this phase would look into space agriculture to understand the types of plants and dietary needs of space settlers and improving the efficiency of crop growth paving the way for self sustaining habitats. Matula has penned a different paper along these lines called The Role of Space Habitat Research in Providing Solutions to the Multiple Environmental Crises on Earth, also attached to the Space Show Blog, which could have duel use applications in addressing environmental problems on our home planet. There are already efforts underway in this arena with Controlled Environment Agriculture (CEA) utilizing greenhouse automation through the Internet of Things leading to reduction of water needs and an increase in crop yields.
“Developing the technology to green the Solar System will also green the Earth for future generations”
Next on the roadmap is lunar industrialization. The focus of this step is to use robotics and in situ resource utilization to minimize the mass of materials lifted from Earth and to create lunar manufacturing capability in a cislunar economy that can be leveraged to build space based habitats for expansion into deep space.
Developing the solar system comes next. Once an economic foundation of industrialization of the Moon has been established, large mobile habitats can be built at the Earth-Moon Lagrange points L1 and L2. Called HALE, for Habitat Autonomous Locomotive Expandable, these are 1km wide self sustaining habitats with 1G artificial gravity capable of low energy transit throughout the solar system including out to the Kuiper Belt, where they can use the resources there to add to their size or build copies of themselves.
The final phase combines mobile free space settlement with advanced propulsion to develop the capability of expansion into the Oort cloud and on to the stars.
“…propulsion technology could advance to a point that would allow mobile space habitats designed for the Oort Cloud to be transformed into the first generational starships.”
A conceptual illustration of the operational layout for a possible future cis-lunar ecosystem based on lunar water resources to refuel GEO satellites and support of a lunar base. Credits: Marc-Andre Chavy-Macdonald et al.*
Most forward looking space planners believe that lunar water will be one of the primary resources that will drive cis-lunar economic activities. But can the growth of a water-based ecosystem be modelled to make future revenue predictions? Using a new methodology that combines System Dynamics with scenario planning a team of researchers in Japan and France has done just that by quantifying the parameters of two scenarios likely to unfold in the near future: a lunar settlement called “Moonopolis” and a long term exploration effort named “Apollo 2.0”. The analysis was just published in Acta Astronautica in a paper entitled The cis-lunar ecosystem — A systems model and scenarios of the resource industry and its impact.
System Dynamics (SD) is time-based modeling to frame, understand, and discuss dynamic behavior of complex systems. Originally developed in the 1950s to improve a company’s understanding of industrial processes, SD is used in both the public and private sectors for policy analysis and to drive strategy.
In the study, the authors* find that three factors are essential for success: government support for R&D, private capital re-investment, and continued growth of the telecom satellite industry in geosynchronous orbit. With these stipulations a cis-lunar economy of $32 billion is projected after 20 years.
Key insights gleaned from this novel holistic model reveal the dynamics of a space resource economy and the interaction of of key technical, policy and socioeconomic variables along with their uncertainties to make future projections.
Incidentally, the authors partnered with a Japan-based company called iSpace on the study which has its own plans for a lunar city called Moon Valley. They are projecting that 1000 people could be living there by 2040.
* Authors of The cis-lunar ecosystem — A systems model and scenarios of the resource industry and its impact: Marc-Andre Chavy-Macdonald, Kazuya Oizumi, Jean-Paul Kneib, Kazuhiro Aoyama
Artist depiction of Starship on the lunar surface returning astronauts to the Moon as part of NASA’s Artemis Program. Credits: SpaceX
What will be the impact on the direction of U.S. space policy should SpaceX successfully demonstrate an orbital flight of Starship? Doug Plata, President and Founder of the Space Development Network believes that when Starship achieves orbit, policy makers should “…place Starship at the center of the country’s human spaceflight program…”. In an article in The Space Review he makes the case that if successful in its efforts, SpaceX may be edging us closer to a tipping point on deciding which path to take for the country’s human rated launch vehicle: Space Launch System (SLS) or Starship? This question is accentuated by recent news reports of yet another delay in the Artemis 1 uncrewed test flight of SLS which Ars Technica reports may not launch until the summer of 2022…assuming everything goes perfectly. Meanwhile, SpaceX continues its development of Starship at a breakneck pace, while simultaneously building the manufacturing infrastructure to “…crank them out by the hundreds”, says Plata. With the delay of Artemis 1, it is possible that SpaceX will demonstrate the first orbital launch of Starship before NASA’s first launch of SLS.
NASA has already selected SpaceX to return astronauts to the Moon via Starship as the Human Landing System for the Artemis program, although work has stalled on the contract due to Blue Origin’s lawsuit. But with a reusable Starship at a fraction of the cost, comparable heavy lift capability and a much higher flight rate, how long can SLS last? A case could be made for keeping SLS until SpaceX’s Super Heavy booster is human rated and Starship can be reliably shown to reenter the Earth’s atmosphere and land safely. But this won’t be long given Elon Musk’s aggressive timelines. Will it continue to make sense to launch astronauts on SLS/Orion, transfer them to Starship in lunar orbit and descend to the surface of the Moon when the the whole mission could be accomplished without SLS at a fraction of the cost?
“At some point, it will be obvious that SLS is an unnecessarily expensive alternative to Starship”
With Starship’s anticipated payload capabilities of delivery of 100s of tons and large crews to the lunar surface, and recent advances in inflatable technology, a habitat with a footprint of about 21,000 sq. ft. is within reach. Plata believes that the billions of dollars slated for SLS would be better spent contracting with SpaceX for delivery of inflatables and their supporting infrastructure to the lunar surface. This could lead to a large international lunar base which may eventually become a permanent settlement.
Conceptual illustration of InstaBase – a fully inflatable lunar base capable of supporting an initial crew of eight. Credits: The Space Development Network via The Space Review
“But there is an important historic significance to Starship as well…the real historic prize to be seized is the establishment of humanity’s first foothold off Earth.”
