An underground habitat on Mars excavated by autonomous rovers reinforced with 3D printed concrete from Martian regolith. Credits Henriette Bier et al.* / Technical University Delft
A team* of researchers at Technical University Delft (TUD) in the Netherlands led by Henriette Bier published a paper last year describing a method for robotically excavating and building structures in cavities below the surface of Mars to provide living spaces for colonists that would be both protected from radiation and thermally insulated from extreme cold. The process would be initiated by autonomous digging rovers hogging out tunnels in a spiral pattern and utilizing the excavated regolith to create concrete for the next step. Using a process developed by TUD called Design-to-Robotic-Production (D2RP) the concrete would be extruded by a 3D printer to reinforce the tunnel walls. Called “Scalable Porosity” TUD has pioneered this process for Earth based architectural applications.
The assumption is that the generated structure is a structurally optimized porous structure, which has increased insulation properties … and requires less material and printing time.
Credits: Technical University Delft
Once structurally sound, the material between the tunnels would be removed to create habitat spaces to be filled by inflatable structures made from materials also sourced in situ.
Although not addressed in detail in the article the authors propose that electrical power be provided by a combination of solar energy and an innovative kite based platform, a highly efficient airborne energy system based on soft wing technology pumped by persistent winds at high altitudes. TUD pioneered this renewable energy technology based on inflatable membrane wings tethered to a ground based generator through its Kite Power research group. A startup called Kitepower B.V. was spun off as a result of this research to commercialize the technology hear on Earth.
Credits: Kitepower B.V.
The D2RP process is data driven and
“…integrates advanced computational design with robotic techniques in order to produce architectural formations by directly linking design to building production.”
For example, the habitat will require a life support system which includes a plant cultivation facility, water recycling and oxygen production controls. These design inputs are coded in the 3D printing program to fabricate the structure around sensor-actuator systems that regulate plant growth and wiring for control mechanisms.
TUD’s goal is to develop a fully self sufficient D2RP system for fabricating subsurface settlements on Mars via ISRU.
* TUD Team members: Henriette Bier, Edwin Vermeer, Arwin Hidding, Krishna Jani
Artist rendering of an earlier version of Starship (formerly BFR, Interplanetary Transport System) approaching Mars. Credits: SpaceX
A mission architecture for Starship is described in a preprint open access article published online December 2 to be released in the next issue of the New Space Journal. The paper lays out a proposed strategy for using the yet to be validated SpaceX reusable spacecraft to establish a self sustaining colony on Mars. The authors* are a mix of space practitioners from NASA, the space industry and academia. No doubt Elon Musk may be thinking along these lines as he lays his company’s plans to assist the human race in becoming a multi-planet species.
Starship is a game changer. It is being designed from the start to deposit massive payloads on The Red Planet. It will be capable of delivering 100 metric tons of equipment and/or crew to the Martian surface, and after refueling from locally sourced resources, returning to Earth. This capability will not only enable extensive operations on Mars, it will open up the inner solar system to affordable and sustainable colonization.
Some of the assumptions posited for the mission architecture are based on Musk’s own vision for his company’s flagship space vehicle as articulated in the New Space Journal back in 2017, namely that two uncrewed Starships would initially be sent to the surface of Mars with equipment to prepare for a sustainable human presence.
“These first uncrewed Starships should remain on the surface of Mars indefinitely and serve as infrastructure for building up the human base.”
The initial landing sites will be selected based on where the water is. The priority will be finding and characterizing ice deposits so that humans will eventually be able to locally source water for life support and to produce fuel for the trip home. The automated payloads of these initial missions will be mobile platforms similar in design to equipment planned for upcoming robotic missions to the Moon in the next couple of years. One such spacecraft, the Volatiles Investigating Polar Exploration Rover (VIPER) is discussed with its suite of instruments that will be used to assess the composition, distribution, and depth of subsurface ice to inform follow-on ISRU operations.
“The use of water ice for ISRU has been determined as a critical feature of sustainability for a long-term human presence on Mars.”
Conceptual depiction of the NASA VIPER rover planned for delivery to the Moon’s south pole in late 2023. A mobile platform with a similar suite of instruments based on this design could be launched to Mars aboard Starship. Credits: NASA
To harvest water from subsurface ice the authors suggest using proven technology such as a Rodriguez Well (Rodwell). In use since 1995, a Rodwell has been providing drinking water for the U.S. research station in Antarctica. The U.S. Army Engineer Research and Development Center’s (ERDC) Cold Region Research and Engineering Laboratory (CRREL) has been working with NASA to prove the technology for use in space in advance of a human outpost on Mars.
Diagram depicting how a Rodriquez Well works. Credits: U.S. Army Engineer Research and Development Center
“Rodwell systems are robust and still in routine use in polar regions on Earth.”
The next order of business is power generation. The authors suggest using solar power as a first choice because the technology readiness level is the most mature at this time. Autonomous deployment of a photovoltaic solar array would be carried out on the initial uncrewed missions. But due to frequent dust storms that could diminish the array reliability, nuclear power may be a more appropriate long term solution once space based nuclear power is proven. NASA’s Glenn Research center is working on Fission Surface Power with plans for a lunar Technology Demonstration Mission in the near future. A solid core nuclear reactor is also an option as the technology is well understood.
These initial missions will robotically assess the Martian environment at the landing sites to inform designs of subsequent equipment to be delivered by crewed Starship missions in future launch windows occurring every 26 months. Weather monitoring will be performed as well as measurements of radiation levels and geomorphology to inform designs of habitats and trafficability. Remotely controlled experiments on hydroponics will also be performed to understand how to produce food. Testing will be needed on excavation, drilling, and construction methods to provide data on how infrastructure for a permanent colony will be robustly designed.
Starship’s ample payload capacity will allow prepositioning of supplies of food and water to support human missions before self sustaining ISRU and agriculture can be established. Communication equipment will be deployed and landing sites prepared for the arrival of people. Much of these activities will be tested on the Moon ahead of a Mars mission.
Production of methane and oxygen in situ on Mars will enable refueling of Starship for the trip home, as envisioned in 1990 by Robert Zubrin and David Baker with their Mars Direct mission architecture. Zubrin’s Pioneer Astronautics may even play a role through provision of equipment for ISRU as they are already working on hardware that could be tested on the Moon soon. One could envision a partnership between Zubrin and Musk as their organizations have common visions, and Zubrin has written about the transformative potential of Starship. When people arrive on Starship during a subsequent launch window after the placement of uncrewed vehicles, further testing of ISRU and life support equipment will be performed with humans in the loop to validate these technologies that will enable Mars settlements to sustain themselves.
If Musk is successful in establishing a permanent self-sustaining colony on Mars will it be a true settlement? The National Space Society in their definition says that a space settlement “..includes where families live on a permanent basis, and…with the goal of becoming…biologically self-sustaining…”, i.e. capable of human reproduction. The definition is agnostic as to if the settlement is in space or on a planetary surface. Musk wants to established cities on the planet housing millions of people by mid century. But does this make sense if settlers can’t have healthy children in the lower gravity of Mars? SSP explored this question in a recent post. Hopefully, once Starship becomes operational, an artificial gravity research facility in LEO will be high on Musk’s priority list to answer this question before he gets too far down the Martian urban planning roadmap. Would he ever consider a change in space settlement strategy in favor of O’Neill type free space colonies? Starship could certainly help facilitate the realization of that vision.
If all goes according to plan, SpaceX will attempt the first orbital flight of a Starship prototype sometime next year, which also happens to be when the next launch window opens up for trips to Mars. Obviously, nothing in rocket development goes according to plan, so the initial flight ready design is at least a year away optimistically. And we know Musk’s timelines are notoriously aspirational. As ambitious as Musk is in driving his company toward the goal of colonizing Mars, it seems unlikely that an initial uncrewed mission with all its flight ready automated hardware as described above could be ready by the next launch window in 2024. But what about 2026? NASA’s current plans for return to the Moon call for a human rated version of Starship as a lunar lander “…no earlier then 2025”. However, Japanese billionaire Yusaku Maezawathe’s Dear Moon mission sending 8 crew members around Luna with a crewed Starship is still planned for 2023. A lot of details are yet to be worked out and we still have not covered the topic of Planetary Protection nor the granting of a launch license to SpaceX by the FAA, but could a Starship human mission to Mars take place in 2028? Let me know what you think.
“The SpaceX Starship vehicle fundamentally changes the paradigm for human exploration of space and enables humans to develop into a multi-planet species.”
* Authors of Mission Architecture Using the SpaceX Starship Vehicle to Enable a Sustained Human Presence on Mars Jennifer L. Heldmann, Margarita M. Marinova, Darlene S.S. Lim, David Wilson, Peter Carrato, Keith Kennedy, Ann Esbeck, Tony Anthony Colaprete, Rick C. Elphic, Janine Captain, Kris Zacny, Leo Stolov, Boleslaw Mellerowicz, Joseph Palmowski, Ali M. Bramson, Nathaniel Putzig, Gareth Morgan, Hanna Sizemore, and Josh Coyan
Conceptual illustration of the Lunar OXygen In-situ Experiment (LOXIE) Production Prototype. Credits: Mark Berggren / Pioneer Astronautics
Here’s a novel way to produce both oxygen and steel in situ on the Moon and eventually on Mars. Under a NASA SBIR Phase II Sequential Contract, Pioneer Astronautics along with team members Honeybee Robotics and the Colorado School of Mines are developing what they call Moon to Mars Oxygen and Steel Technology (MMOST), an integrated system to produce metallic iron/steel and oxygen from processed lunar regolith.
In a presentation at a meeting of the Lunar Surface Innovation Consortium last month, Mark Berggren of Pioneer Astronautics gave an update on the team’s efforts. Progress has been made on several key processes under development as part of the overall manufacturing flow. Output products will include oxygen for either life support or rocket fuel oxidizer and metallic iron for additive manufacturing of lunar steel components.
MMOST process flow diagram. Credits: Mark Berggren / Pioneer Astronautics
The immediate next steps for the MMOST development program will be continual refinement of each process module, protocols for minimization of power requirements, demonstration of LOXIE in a vacuum environment and then optimization of mass, volume and power specifications for a scaled-up system toward flight readiness hardware.
Potential follow-on activities may include a robotic sub-scale LOXIE lunar flight experiment that could be sent to the Moon via a Commercial Lunar Payload Services (CLPS) lander. As part of the Artemis program crews could possibly demonstrate a pilot unit to validate manufacturing in the lunar environment. If successful, a full scale MMOST commercial system could come next in support of lunar base operations as part of a cis-lunar economy.
Image of Lunar Transporter (L-Tran) with Lunar Regolith Excavator (L-Rex) stored on board as they roll down a ramp from a lunar lander. Credits: screen capture from Redwire Space animation. All images below are so credited.
NASA has just announced the winners of the Breaking the Ice Lunar Challenge, an incentive program for companies to investigate new approaches to ISRU for excavating icy regolith from the Moon’s polar regions. The agency will be awarding half a million dollars in cash prizes and Redwire Space headquartered in Jacksonville, Florida won first prize scoring $125,000 for its elegantly designed two rover lunar excavation system. The criteria used by NASA to select the winners was based on maximum water delivery, minimum energy use, and lowest-mass equipment.
Upon delivery by a lunar lander near a shadowed crater in the Moon’s south polar region, a multipurpose Lunar Transporter (L-Tran) carrying a Lunar Regolith Excavator (L-Rex) rolls down a ramp to begin operations on the surface. The rover transports the excavator to the target area where icy regolith has been discovered.
Image of L-Rex driving off of L-Tran
The L-Rex then drives off the L-Tran to start collecting regolith in rotating cylindrical drums on the front and back of the vehicle.
L-Rex collecting lunar regolith in fore and aft collection drumsL-Rex loading regolith into L-Tran for transport back to processing station
When the drums are full, L-Rex returns to the rover and deposits its load in L-Tran’s storage bed. L-Rex repeats this process over many trips until L-Tran is loaded to capacity at which point the rover returns to a processing facility to separate the water from the regolith.
L-Tran dumping a load of regolith into a hopper at a processing facilityAfter regolith beneficiation the separated frozen water ice is loaded into L-Tran for transport to secondary processing plant
Upon separation into purified frozen ice, L-Tran is once again loaded up with the product for transport to a station for storage or perhaps, further processing. No further details were provided but the final process is presumed to be electrolysis of the water into useful end products such as H2 and O2 for rocket fuel or life support uses, plus simply storage as drinking water for human habitation.
L-Tran loading water ice into hopper for final processing into end products or simply storage
The second place prize of $75,000 was awarded to the Colorado School of Mines in Golden, Colorado for its Lunar Ice Digging System (LIDs). The LIDS proposal has three rovers – an excavator, regolith hauler, and water hauler each of which would be teleoperated from a nearby lunar surface habitat.
Austere Engineering of Littleton, Colorado won the $50,000 third place prize for its Grading and Rotating for Water Located in Excavated Regolith (GROWLER) system. The system weighs slightly more then a school bus tipping the scales at an estimated mass of 12 metric tons.
A second phase of the challenge, if approved, could move the proposals into hardware development and a future demonstration mission toward eventual support of lunar habitats and a cislunar economy.
Checkout Redwire’s animation of their lunar excavation system:
Animation from Redwire Space’s Breaking the Ice Lunar Challenge proposal. Credits: Redwire Space
Conceptual depiction of the Pinwheel Magma Reactor on a planetary surface in the foreground and in free space on a tether as shown in the inset. Credits: Kevin Cannon
How can space settlers harness useful resources that have not been concentrated into ore bodies like what takes place via geologic process on Earth over eons of time? Could we artificially speed up the process using synthetic geology? Kevin Cannon, a planetary geologist at the Colorado School of Mines (CSM), thinks it might be possible to unlock the periodic table in space to access a treasure trove of materials with an invention he calls the Pinwheel Magma Reactor. He has submitted a NASA Innovative Advanced Concepts proposal for the concept. The device is a essentially a centrifuge sitting on a planetary surface with a solar furnace reaction chamber spun at the end of its axis. In space, a free flying system could be connected by tether.
PMR chambers are positioned at the end of the axis of a centrifuge. Credits: Kevin Cannon
In a Twitter thread Cannon sets the table with a basic geology lesson explaining why mining on Earth is so different from what we will need in space. The Earth’s dynamic crustal processes, driven by fluid flow and plate tectonics over millions of years, exhibit a very different geology then that under which the Moon, Mars and asteroids evolved. The critical minerals that could be useful to support life and a thriving economy in space settlements are present in far lower concentrations in space then on Earth.
Current plans for ISRU infrastructure on the Moon and asteroids are only targeting a small set of elements like hydrogen, oxygen, carbon, silicon and iron (below, left).
Illustration of the periodic table showing currently targeted elements for ISRU on the left. On the right, the most mined elements on Earth (colored gold) and critical elements (orange) useful for an advanced society. Credits: Kevin Cannon
But an advanced society expanding out into the solar system would benefit from many critical minerals (above, right) that are not easily accessible because of their far lower concentrations. For example, energy production will need uranium and thorium, energy storage systems require lithium and electronics manufacturing is dependent on rare earths. So how to unlock the periodic table for these critical materials?
If we are to live off the land by harvesting useful materials to build and sustain space settlements we’ll need a totally revolutionary mining process. The PMR was designed with this in mind. The procedure begins by loading unprepared rocks or regolith into the chamber followed by heating via a solar furnace. Next, the chamber is spun up in the centrifuge where super gravity concentrates the desired minerals. Cannon believes that the PMR could also be used to extract water from regolith on the moon or asteroids.
“If hydrated asteroid material or icy regolith are put in at low temperatures, they’ll be separated by super-gravity and can be siphoned off.”
Of course the technology needs to be validated and flight hardware developed to determine if the PMR can be a tool to speed up the geological processes to concentrate useful materials for humans, who can then use them to synthetically propagate life in space. Cannon sums it up:
“Obviously a lot of work to be done to prove out the concept. But I think that a process flow of synthetic geology -> synthetic biology is the way to solve the concentration problem in space and enrich any element we want from the periodic table.”
Artist depiction of a lander descending to the lunar surface carrying a rover housing Masten’s Rocket Mining System. Credits: Masten Space Systems
Called RocketM for Resource Ore Concentrator using Kinetic Energy Targeted Mining, Masten Space Systems has partnered with Honeybee Robotics and Lunar Outpost to design a novel system for blasting ice out of lunar regolith for ISRU under NASA’s Break the Ice Lunar Challenge program.
Lunar Outpost rover decending to the lunar surface down a ramp deployed off a Masten lander. Credits: Masten Space Systems
RocketM equipment would be housed aboard a Lunar Outpost rover delivered to lunar surface via Masten’s lunar lander. After unloading, the rover would be robotically navigated by a geologic team to an excavation site in the Aitken Basin near the Moon’s south pole. Upon arrival over the target area, the RocketM dome is extended down to the surface to create a seal over the regolith. A rocket is then ignited in a series of 1/2 second pulses fluidizing the regolith into icy grains which are conveyed out of the dome via a Honeybee Robotics PlanetVac pneumatic sampling system for processing. Beneficiation of the particles is accomplished using an Aqua Factorem process for separation into purified ice and other useful components. Aqua Factorem has been covered by SSP in a previous post. The whole process would only take 5-10 minutes.
A view of the inner workings of RocketM showing a centrally located pressure dome extending down to form a seal on the lunar surface. Credits: Masten Space SystemsCutaway view showing a 100lb thrust rocket engine firing half-second bursts to heat the regolith to a depth of 2 meters releasing icy grains for processing to extract water. Credits: Masten Space Systems.
The stored water can subsequently be electrolyzed using solar energy into hydrogen and oxygen for lunar operations. What is so exciting about this ISRU system is that the rocket engine can be refueled by the mined products enabling an estimated useful life of 5 years.
Masten has tested the system using simulated lunar regolith providing groundwork toward optimizing conditions within the pressure dome. Further testing is needed at the system level to validate flight readiness.
As stated on Masten’s blog: “Usable as drinking water, rocket fuel, and other vital resources, lunar ice extraction is critical to maintain a sustained presence on the Moon and allow future missions to Mars and beyond. It can also be used in conjunction with other volatiles found in lunar regolith, such as oxygen and methane, to support energy, construction, and manufacturing needs. There’s a lot of promise – water excavation is just step one!”
Artist renderings of an autonomous pneumatic handling system using SHEPHERD technology. An asteroid is first carefully enclosed in a touchless manner within a sealed fabric envelope, de-spun and de-tumbled through friction with an introduced controlling gas, then driven by continuous gas flow to introduce delta-V and deliver the asteroid to a target destination. Chemical and thermal interaction between the introduced atmosphere and the asteroid will permit fuel and water extraction, 3D electroforming of parts from metal sources and the creation of in-space biospheres to feed large habitats. Concept depicted by: Bruce Damer and Ryan Norkus with key design partnership from Peter Jenniskens and Julian Nott. Note: all of the illustrations in this post are credited as above unless otherwise indicated
The SHEPHERD concept for gentle asteroid retrieval with a gas-filled enclosure, an SSP favorite open source technology, has been covered in a previous post. Dr. Bruce Damer, one of the coinventors of the system, recently appeared on SpaceWatch.Global’s Space Café podcast where he revisited this promising technology for capturing asteroids, mobilizing them and extracting key materials to support space settlement (which can be found near the end of the recording). SHEPHERD could solve the three main sourcing problems of sustainable spaceflight and habitation: harvesting volatiles, building materials, and sources of food. Dr. Damer has also been busy with his (and UCSC Prof. David Deamer’s) Hot Spring Hypothesis, a testable theory regarding the place and mechanism of the life’s origins on the Earth, which was the main focus of the podcast. In fact, the arc of his career has tied these two endeavors together in interesting ways. SSP reached out to Dr. Damer for an exclusive interview via email on these groundbreaking topics.
SSP: Dr. Damer, thank you so much for taking the time to answer my questions about SHEPHERD. I’ve been excited and intrigued with the technology ever since I saw the initial paper and your 2015 TEDx talk. Can you give our readers an overview of the concept?
Damer: The goal for SHEPHERD is to provide a universal technology to open the solar system to sustainable spaceflight and beyond that, to large scale human colonization (see figures and explanations for Fuel, Miner and Bio variants below). Enclosing an asteroid (or Near-Earth Object-NEO) within a fabric membrane and introducing a controlling gas would turn that asteroid into a “small world”. The temperature of the gas, its chemical composition and gas pressure forces set up within it can enable multiple in-situ resource utilization (ISRU) scenarios. Initially, the extraction of water and other volatiles from icy NEOs could provide fueling stations with deliveries throughout the solar system. Next, the use of the Mond-process carbonyl gas extraction from high-metallic NEOs can provide electroform 3D printing of large parts in space for construction of habitats. Lastly, melting the ice content of a NEO to a liquid phase surrounding its rocky core enables the introduction of microbes, algae and even some aquatic animals into a biosphere, a mini-Earth terrarium sustained in space. This one invention could provide many of the elements necessary for sustainable spaceflight but also for the construction and support of in-space and surface-located planetary and lunar habitats for thousands or millions of inhabitants. Co-inventor of the design, Dr. Peter Jenniskens at the SETI Institute, calls this the “sailing ship for space” harkening back to how his Dutch ancestors helped open the Earth to commerce centuries ago.
SHEPHERD-Fuel variant with volatiles such as water ice sublimating from the NEO into a warming gas, the resulting water vapor pumped down and condensed into liquids in storage tanks and then separated into hydrogen and oxygen. These tanks become the fuel source for a self-propelling tanker block which can be delivered to a refueling rendezvous point such as Earth cislunar space or Mars orbitSHEPHERD-Miner version with an introduced carbonyl gas and an electric field dipole drawing off ions from a metallic NEO and layering them on a mandrel (shown on the left) to create a precision 3D part such as blocks, beams or tanks for space habitat constructionSHEPHERD-Bio variant sustaining a liquid biosphere around the rocky core of a NEO, with a lit interior and boom to introduce and extract organic materials. A balance of microbes, algae, and even small aquatic animals could maintain this small world, a “terrarium in space” to support large populations in habitats and at surface coloniesSHEPHERD-Fuel variant in Mars orbit or at some distance away showing the delivery of re-fillable tanker block sections to a Mars mission, the nearly empty block propelling itself for refilling. In this way ample fuel is provided in-situ prior to the craft arriving at Mars, with mission lander fuels, water for human consumption, shielding and return propellant provided in orbit in advance without having to extract volatiles from the Mars atmosphere or regolithVision of SHEPHERD Miner and Bio variants supporting a large habitat in LEO with the mantra of: “built in space, and fed in space”
SSP: Have there been any developments or updates to the concept since the initial TEDx talk and NewSpace Journal paper which both came out in 2015?
Damer: Back then we thought that no company or government had the will or capability to invest in such an opportunity, but this is now changing. The roaring success of NewSpace ventures such as SpaceX and their dual award of NASA’s Artemis Program returning humans to the moon based on reusable crewed launches and their recent successful low altitude testing rounds for Starship, has totally changed the space landscape of the near future. Jeff Bezos’ vision for megastructures in space based on the O’Neill colonies of the 1970s would require substantial asteroid resourcing. Elon Musk’s vision for large surface colonies on Mars would be equally well supported by simple, automated space based ISRU which overcomes substantial mining and manufacturing hazards attempting to process bulk materials on the surface of Mars or the moon. In addition, Bigelow’s success with inflatables, China’s surging space program with a new crewed station and rovers on the moon and Mars, all point to much more traffic and demand, especially for fueling depots, as early as the mid-2030s. Reducing the cost of lifting heavy and bulky materials from Earth may never be competitive to extraction, electroforming and farming in space with low-cost delivery directly to points of demand.
Earlier this year I determined that the time was right to place our invention out into the field again and seek partners to join in a development roadmap that will provide a solid financial and technical ladder for SHEPHERD’s maturation.
At a NASA/SETI meeting in January 2019 I was discussing SHEPHERD with members of the Luxembourg Space Agency and was overheard by space entrepreneur Carlos Calva. He approached me and offered that he would work with me to make SHEPHERD into a business. Subsequent meetings at SETI with my co-designer Peter Jenniskens (Julian Nott had died tragically in a ballooning accident) gave us early insights into SHEPHERD’s developmental timeline.
In that spring of 2019 Carlos and I engaged in a rapid-fire series of meetings developing a short-term cash business model for SHEPHERD which would provide a financial lever for the technology. Capturing, moving, and extracting resources from asteroids is a longer-term (15+ years) play, with no immediately apparent buyer for the first potential products: volatiles for propulsive fuel, air, water, and other crew consumables. Elon Musk and SpaceX might reach a point in this decade when they would buy a futures contract for hundreds, or thousands of tons of water and fuel delivered into Earth and Mars orbits sometime in the 2030s. Jeff Bezos may also want to finance the development of SHEPHERD as a technology for delivery of resources to build space habitats much as he has with Amazon’s funding of drone and other robotic fulfillment innovations.
But how to prove SHEPHERD as a technology and then sustain it as a business for long enough to be ready for either of these clients? We settled on two emerging market opportunities: 1) satellite servicing and decommissioning, and 2) hazardous debris removal and deorbiting. Both are potential cash businesses that could provide us achievable milestones to support the multiple investment rounds required. Satellite servicing and debris removal or de-risking is an urgent unmet market need for both governments and commercial operators worldwide. Along with the CubeSat revolution, SpaceX’s reusable launch platform and Bigelow Aerospace’s success with the inflatable Genesis and BEAM module on the ISS, many core technologies were maturing.
Making SHEPHERD into a viable sailing ship for space will not be without its challenges. Designing and flying a fabric enclosure which can open, admit an object (a satellite, a chunk of debris, or a space rock) and then closing it tight, sealing it well enough to fill it with a controlling gas was a major technical challenge which NASA identified in their review of our 2014 Broad Agency Announcement proposal for the asteroid redirect program (since cancelled). The tried-and-true way to make a new space system work reliably is to build scale models, test them to failure, and test them again.
SSP: You mentioned that some of the capabilities of the system could be tested in LEO with CubeSats. Since the technology is open source, has anyone reached out to you to develop hardware for such an experiment? What would be tested and how?
Damer: Carlos and I made a bee-line for the world-renowned annual CubeSat Developer Conference meeting at Cal State San Luis Obispo in April of 2019 where we were able to interact with many of the leading thinkers and solution providers in the CubeSat industry. We devised a back-of-an-envelope LEO test vehicle flight series and made some key contacts. For a small investment (2-4 million USD), an effective six test flight series with a 4U CubeSat would first deploy a gas filled bag into which we could release a target object (such as a real meteorite which would be returned to space). The images below depict this scenario. Later flights in the series could have the target released to space and then the CubeSat would match orbits, track, enclose and seal the object into the enclosure. Key for any test is the ability to manage the object within the enclosure such that it does not contact the fabric. This would not be an issue for our small CubeSat, but it would be a potentially catastrophic encounter for a satellite or NEO. The key to safety (SHEPHERD stands for Secure Handling through Enclosure of Planetesimals Headed for Earth-Moon Retrograde Delivery) is that the system is touchless. In the image below we see gas jets firing to move the object toward and hold it in the center of the enclosure.
SHEP Cube test vehicleInflation of bag enclosure using controlling gas, introduced target object (perhaps a meteorite returned to space)Management of target object position with gas jetsLit interior showing target centered safely in the enclosure
All of this early effort to build and fly the CubeSat missions would mature our IP including: tracking, gas fluid dynamics for handling and enclosure deployment and sealing. We could then value the company and seek a round of investment from governmental or commercial partners in the satellite servicing and debris removal markets.
SSP: How do you foresee these two potential near term commercial applications generating sufficient revenue to “pay the way” for SHEPHERD to achieve its long-term goals?
A much larger SHEPHERD version with an enclosure for capture and servicing of a high value large satellite. Servicing could either be carried out with a robotic bay or by astronaut mechanics flying on SpaceX Dragon, who enter through an airlock and can breathe a low-pressure Earth atmosphere negating the need for bulky EVA/space suits
Damer: Paying the way for SHEPHERD could come from a mixture of satellite servicing (expensive “big birds” for the US DOD or communication satellite operators), orbit graveyarding (for GEO, or de-orbiting from LEO), and of course mitigation of dangerous space debris to head off Humanity’s disastrous encounter with the “Kessler syndrome” as depicted in the movie Gravity. In-space satellite servicing via robotic spacecraft is problematic, requiring very high-risk grappling procedures between vehicles which have no built-in standard grappling mechanism. SHEPHERD provides a gas-based “pneumatic” way to safely envelop and control spacecraft without hard contact. Early computational studies at the SETI institute in 2014 established that a shape model of multi-ton asteroid 2008 TC3 could be de-tumbled and de-spun in less than 24 hours if the object was interacting within a gas at 10% Earth atmosphere pressure. The friction of the satellite or chunk of debris with the gas will bring it to a standstill, then gas jets can be used to rotate and position the enclosed spacecraft for servicing. Imparting a continuous driving force onto the craft using these same jets can create sufficient delta-V to change its orbit. Such safe handling and mobilization of objects in space is key to a whole range of future space operations. The irregularity of satellite shapes (including long booms or antennae) presents fewer challenges to SHEPHERD’s scale and size-independent gas handling system than they would to a robotic or crewed “jet pack” style EVA servicing as we saw with the Space Shuttle’s Hubble servicing missions.
If a satellite servicing, extension of life, or safe decommissioning capability were clearly on the horizon, supporters of international treaties and reinsurance companies could create guaranties, service contracts and insurance instruments which would finance a first generation of SHEPHERD vehicles.
SSP: What do you see as the full vision for the sustainable space architecture which SHEPHERD could enable?
A full vision of the architecture enabled by SHPHERD supporting near-Earth habitats, interplanetary missions, and a class of continuously cycling robotic and crewed spacecraft. Cycling visits of SHEPHERD ISRU supply depots could capture, relocate and extract from asteroids of all sizes and compositions. Eventually a mature SHEPHERD architecture could scale up enclosure sizes to provide the Earth a comprehensive planetary protection shield from larger NEO impact hazards
Damer: The image above depicts the enabling of SHEPHERD-derived spacecraft and processing facilities to support both near Earth space stations and larger megastructure colonies, robotic and human exploration of the inner solar system and beyond. I envision the SHEPHERD business being most akin to the mining industry I was raised around in British Columbia and as depicted in the Sci Fi series The Expanse. Some companies would fly prospecting (and orbit determination) missions to NEO targets, file claims and then sell them on to development companies. Those companies would license or build SHEPHERD-class spacecraft financed through contracts for future deliveries of commodities to companies and governments. Buyers would eventually acquire the risk-taking development companies and leverage them to support much larger projects such as space settlement megastructures or to supply Mars surface colony operations. Over time, scaling of the SHEPHERD system enclosure sizes would permit the safe handling and redirection of Earth-threatening asteroids giving us all a planetary protection shield. A great deal of Astrobiology science could also be supported such as the delivery of a pristine carbonaceous asteroid to Lunar orbit (see below) for astronaut geologists to sample. These samples might give us clues as to how life began on the Earth through the delivery of abundant organics from asteroids like this.
Release of pristine asteroid into Lunar orbit to support sampling by Astrobiologists looking for clues to life’s origins on the Earth, four billion years ago
SSP: What are the next steps for SHEPHERD?
Damer: The COVID-19 pandemic caused a pause on SHEPHERD’s development both as an engineering concept and a business. When I was invited to appear on the Space Café podcast in April (of 2021), I decided to bring it up again to gauge public interest and bring it to leaders in New Space. This interview with you is the next step in developing that interest, calling forward a development team. What I am also seeking is critical input from the community on the concept, leadership in research, and the formation of a company or university research program with financial support for the early on-ground computational and test-article studies leading up to CubeSat flights.
I specifically “open sourced” the basic concept of SHEPHERD on behalf of the three co-inventors in my 2015 TEDx talk, but IP developed by one or more implementers of this core concept can provide them and their investors with protectable value. The seal closure will be one key patentable innovation. Together with a team of keen and willing supporters including myself and Carlos, we produced a pitch deck which was first premiered at the Space Resources Roundtable held at the Colorado School of Mines in May of 2019. This deck concisely lays out the initial cash business in satellite servicing and debris removal and the engineering we have done around the CubeSat and larger variants. Carlos is back at work on the key steps of recruiting engineering leadership and funding for the ground-based development. I am open to inquiries from qualified contacts who wish to discuss their involvement seriously.
SSP: As you described above, of the three key applications of SHEPHERD, one could be food production for space settlements by creating a fully self-contained biosphere out of an asteroid, a mini-Earth if you will. This complements your Hot Springs Hypothesis for life’s beginnings in its method for seeding space with life beyond Earth. Is there an underlying principle linking the origin of life and humanity’s role in extending it beyond the cradle of the Earth?
Series of three images showing cellular mitosis beginning with fission of the nucleus, mitosis underway and completion of the process with daughter cells separatedSHEPHERD Bio with image of Earth overlain on its 500m diameter terrarium worldMitosis of the Earth into “daughter worlds” represented by the arising of SHEPHERD-Bio in the solar system
Damer: Thank you for asking this question! A couple of years ago I literally sat bolt upright in bed having had a dream of a future vision of the solar system, possibly from the year 2100. A ring of asteroids had become enclosed with SHEPHERD craft or some derivative thereof, and thousands to millions of “new worlds” were orbiting the sun. In nearby orbits were the sharply geometric and tubular shapes of space settlements under construction, housing billions of humans and the organisms with which they cohabitate. Evolution had a future path, moving off our birth world by first creating many new ones. Like the first living cells, the Earth had undergone a spectacular mitosis! I realized in a flash that this future solar system was a huge scale evolution of the ancient hot spring pool cycling with membrane-enclosed protocells which Dave Deamer and I have proposed for life’s beginning. The principal of membranous encapsulation enabling chemical activity and resource sharing acted out four billion years ago in hot spring pools would return to enable life to emerge from the womb of the Earth into a long evolutionary future in the cosmos. It was truly gratifying. You can see how I then wove together these stunning parallel visions in my two TEDx talks below.
The SHEPHERD project is dedicated to the memory and genius of Julian Nott (right) at home in Santa Barbara during my 2014 visit
Diagram depicting the three main areas of in-situ resource utilization and their connections to surface systems. Credits: ISECG
The International Space Exploration Coordination Group (ISECG), a forum of 14 space agencies which aims to implement a global space exploration strategy through coordination of their mutual efforts, established a Gap Assessment Team (GAT) in 2019 to examine the technology readiness of in-situ resource utilization (ISRU). The purpose of the ISRU GAT effort was to evaluate and identify technology needs and inform the ISECG on gaps that must be closed to realize future missions. The assessment was intended to initiate an international dialogue among experts and drive policy decisions on investment in exploration technologies, while identifying potential areas for stakeholder collaboration. A report has just been released summarizing these efforts.
ISRU systems that can collect and utilize resources available at the site of exploration, instead of transporting them from Earth with considerable expense, cover three broad areas depicted in the diagram above; In-Situ Propellant & Consumable Production, In-Situ Construction, and In-Space Manufacturing with ISRU-Derived Feedstock.
To help understand how each function interacts and influences other areas of ISRU and how they integrate with life support systems, a functional flow diagram shown below was created to help visualize the flow of resources step by step to final product realization.
Integrated ISRU functional flow diagram (Including ties to life support). Credits: ISECG
The GAT reached consensus on key findings and recommendations (listed below) to stakeholders and decision-makers for implementing ISRU capabilities deemed essential for future human space exploration and settlement activities.
Key Findings * ISRU is a disruptive capability and requires an architecture-level integrated system design approach from the start. * The most significant impact ISRU has on missions and architectures is the ability to reduce launch mass, thereby reducing the size and/or number of the launch vehicles needed, or use the mass savings to allow other science and exploration hardware to be flown on the same launch vehicle. The next significant impact is the ability to extend the life of assets or reuse assets multiple times. * The highest impact ISRU products that can be used early in human lunar operations are mission consumables including propellants, fuel cell reactants, life support commodities (such as water, oxygen, and buffer gases) from polar resources (highland regolith and water/volatiles in PSRs). * While not in the original scope, evaluation of human Mars architecture studies suggest that there is synergy between Moon and Mars ISRU with respect to water and mineral resources of interest, products and usage, and phasing into mission architectures. * A significant amount of work is underway or planned for ISRU development across all the countries/agencies involved in the study, particularly in the areas of resource assessment, robotics/mobility, and oxygen extraction from regolith. * While it appears each country/space agency has access to research and component/subsystem size facilities that can accommodate regolith/dust and lunar vacuum/temperatures, there are a limited number of large system-level facilities that exist or are planned. * The assessment performed on the type and availability of lunar and Mars simulants for development and flight testing shows that 1) while simulants are available for development and testing, greater quantities and higher fidelity simulants will be needed soon, especially for polar/highland-type regolith, and 2) selection and use of proper simulants is critical for minimizing risks in development and flight operations. * Examination of resource assessment development and activities identified new efforts in refocusing technologies and instrumentation for lunar and Mars operations, and several missions to begin surface and deep assessment of resources are in development, especially to obtain maps of minerals on the lunar surface, surface topography, and terrain features, or to understand the depth profile of water and volatiles. * While there is significant interest in terrestrial additive manufacturing/construction development, development for space applications has been limited and primarily under Earth-ambient conditions. * Further research, analysis, and engagement are required to identify synergies between terrestrial mining and in-situ resource utilization (ISRU). Throughout the mining cycle and ISRU architecture, key areas for investigation include; dependence on remote, autonomous, and robotic operations; position, navigation, and timing systems; and energy technologies (e.g., small modular reactors and hydrogen technology). * Stakeholder engagement is required between the terrestrial mining and space sectors to drive collaboration to identify and benefit from lessons learned from terrestrial innovations for harsh or remote operations. * Long-term (months/years) radiation exposure limits for crew currently do not exist to properly evaluate radiation shielding requirements. These are needed to properly evaluate Earth-based and ISRU-based shielding options.
Recommendations * To help advance ISRU development and use in future human exploration, it is recommended that countries/agencies focus on the defined Strategic Knowledge Gaps (SKGs) that have been identified as high priority for each of the 3 human lunar exploration phases described. Early emphasis should be placed on geotechnical properties and resource prospecting for regolith near and inside permanently shadowed regions. * Since the access and use of in-situ resources is a major objective for human lunar and Mars exploration and the commercialization of space, locating, characterizing, and mapping potential resources are critical to achieving this objective. While work on resource assessment physical, mineral, and water/volatile measurement instruments are underway, and new orbital and lunar surface missions are in development or planned, a focused and coordinated lunar resource assessment effort is needed. It is recommended that Science, ISRU, Human Exploration, and Commercial Space coordinate and work closely on Geodetic Grid and Navigation, Surface Trafficability, and Dust and Blast Ejecta to ensure surface activities and data collection are performed efficiently and safely. * While short-duration lunar surface crewed missions can be completed with acceptable radiation exposure risk, it is recommended that long-term exposure limits be established and radiation shielding options (Earth and ISRU-based) be analyzed as soon as possible to mitigate risks for sustained operations by the end of the decade. * Long-term sustained operations will require a continuous flow of missions to the same location. While distance and placing of landers can be initially used to mitigate damage to already delivered equipment and infrastructure, an approach for sustained landing/ascent (in particular for reusable vehicles and hoppers) is needed. Dedicated plume-surface interaction analysis and mitigation technique development are recommended. It is also recommended that development of capabilities and establishment of landing/ascent pads be incorporated into human lunar architectures early to support sustained operations * Experience from Apollo missions indicates that wear, sealing, and thermal issues associated with lunar regolith/dust may be a significant risk to long-term surface operations. Coordination and collaboration on dust properties/fundamentals, and mitigation techniques and lessons learned are highly recommended. This effort should also involve coordination and collaboration on the development, characterization, and use of appropriate lunar regolith simulants and thermal-vacuum facility test capabilities and operations for ground development and flight certification. * To maximize the use of limited financial resources, it is recommended that the ISECG space agencies leverage the information presented in the report, in particular, the content of the “Technology Capture by WBS and Country/Space Agency portfolio” as a starting basis for further discussions on collaborations and partnerships related to resource assessment and ISRU development/operations. * Collaboration and public-private partnerships with terrestrial industry, especially mining, resource processing, and robotics/autonomy are recommended to reduce the cost/risk of ISRU development and use. * This includes establishment of an international regulatory framework for resource assessment, extraction, and operations, which are necessary to promote private capital investment and commercial space activities. * The sustainable development aspects of the ISRU activity are recommended to be taken into account from the start of activity planning for the surface exploration of Moon and Mars. * Aspects of reusing and recycling hardware are recommended to be taken into account from the design and architecture phase of mission planning. This will contribute to minimizing the exploration footprint (e.g. abandoned hardware) and therefore is key towards sustainability. * To accelerate the development of key technologies, close knowledge gaps, and expedite testing/readiness, it has been seen that the use of unconventional models, such as government-sponsored prize challenges can be effective innovation catalysts operationalizing the above recommendations, and ultimately, bringing ISRU to the Moon and onwards to Mars.
Planetoid Mines Corporation’s ISRU off-world extractor. Credits: Planetoid Mines Corporation
A New Mexico based startup called Planetoid Mines Corporation has just completed development of an autonomous robotic platform for mining the moon or other extraterrestrial worlds via in situ resource utilization. The system features a multi-head icy regolith extractor that feeds directly into an ore beneficiation tool, the output of which is channeled to an onboard oven that extrudes 3D printed structures via a robotic arm.
Through a post on his LinkedIn profile, CEO Kevin DuPriest says “Our self-contained system provides end-to-end continuous mining operations with multiple excavator heads, mineral concentration through beneficiation, a pyrometallurgy oven and thermal printing head. Using lunar surface minerals the system can print landing pads, extrude fused quartz rods, large antenna arrays, etc. ISRU platform designed to fit most lunar landers.”
The company’s website highlights a solid oxide hydrogen fuel cell and steam electrolysis stack that can split lunar water into hydrogen and oxygen for rocket fuel while generating heat and power on-demand. There is even potential dual use benefits of the ISRU architecture for mining on Earth. The website intimates the possibility of a mission to the Moon by 2022, but provides no further details on suppliers of launch or lander services.
In a recent Tweet DuPriest announced the company is considering going public through a Special Purpose Acquisition Corporation (SPAC) and looking for partners to assist with cislunar infrastructure and logistics for mission operations.
Illustration of Ablative Arc Mining Process. Credits: Amelia Greig
A NASA NIAC Phase 1 grant has been awarded to Amelia Greig of the University of Texas, El Paso to study an innovative mining technique called ablative arc mining. The process works by using a pair of electrodes to zap surface regolith with an electrical arc thereby ionizing it into its component constituents. The ablated ions are then sorted and collected by subjecting them to an electromagnetic field which separates the material groups by their respective mass. Such a system, when mounted on a mobile rover, could extract both water and metal ions in the same system.
The goal of the this grant is to identify a feasible ablative arc mining scheme for ISRU on upcoming lunar exploration sorties. The study will define the design of an ablative arc and electromagnetic transport system for extraction and collection of water, silicon, and nickel. The architecture should have an output of 10,000 kg/yr of water for use by lunar outposts or other operations. Finally, a trade study will be performed comparing the efficiency of the proposed concept against other ISRU processes such as microwave or direct solar heating which are designed to only collect a single constituent.
We’ll need ISRU methodologies to enable long-term space settlement on the Moon, Mars, in the Asteroid Belt or to support free space habitats. The ablative arc mining architecture may be an efficient alternative for extraction and collection of multiple volatile constituents in a single system when compared to methods that collect only one material at a time.
