Optical Mining

NASA Credits: Joel Sercel

Advanced thinking to explore nature all around us for the benefit of mankind is always an integral part to science and technology. Taking note of the number of asteroids/craters making rounds in the space as a possible treasure of minerals, scientists and engineers are planning to develop and design technology not only to explore these store houses but also to extract or mine the same for the benefit of mankind. Success in exploring and mining could further be helpful to establish a sustained human presence in space. Advanced robotic technologies at present are enabling the exploration of space. Proposed technologies can help to rapidly survey and model craters and asteroids and space missions can be further designed to use these high-resolution images and the data would be used to determine whether a crater/asteroid can be explored by human or robotic missions.

Optical Mining technology is a breakthrough approach to harvesting materials from asteroids, boulders, and regolith in microgravity. In Optical Mining, excavating and processing asteroid materials is accomplished by highly concentrated sunlight which we have shown can be used to drill holes, excavate, disrupt, and shape an asteroid while the asteroid is enclosed in a containment bag. It actually digs holes and tunnels into the rock. The heat goes in, is absorbed in thin layers and drives out the volatiles in tiny, explosive like pops that eject material in a controllable way. Researchers believe that highly concentrated sunlight can drill holes, excavate, disrupt and shape an asteroid while the asteroid is enclosed in a containment bag.

The process of mining asteroids is a complicated one and the project will demonstrate the feasibility of an innovative breakthrough in methods of Optical Mining. The mission concept aims to prove that optical mining, in conjunction with other innovative spacecraft systems, which can be used to obtain propellant in space. The proposed architecture includes resource prospecting, extraction, and delivery. First a suitable candidate (high % of water and a manageable size) must be identified and selected from hundreds of thousands. Next a mining craft is sent out to bag it for mining. Following the bagging, mining begins by focusing the sun’s rays onto the asteroid, fracturing the asteroid into pieces and releasing the water inside. The water is collected in cryobags to freeze and store water for future use. Optical mining is an approach to simultaneously excavating carbonaceous chondrite asteroid surfaces and driving water and other volatiles out of the excavated material and into an enclosing inflatable bag without the need for complex or impractical robotics. In optical mining, highly concentrated sunlight is delivered to the surface of the asteroid through a mechanically simple but optically sophisticated system of reflective non-imaging optics. The highly concentrated optical energy ablates the surface in a controlled way analogous to how intense lasers can ablate surfaces constantly exposing new material and forcing water out of the ablated material. Optical Mining provides the raw material for all future space industries. By using energy from the sun a prototype model has been proposed as a simple and efficient method for mining asteroids at rates of up to tons per month.??

Development status

NASA NIAC Phase 1 work demonstrated Optical Mining in the laboratory and performed mission and systems analysis of the application of Optical Mining to human exploration missions. The mission analysis showed that the most accessible Near Earth Objects (NEOs) can be used to provide NASA with mission consumables for human exploration in deep space with the potential of saving up to $10B/yr or $150B over the 15 year operational life cycle of a human exploration program. This savings alone would be enough to transform NASA’s vision of human exploration from being unaffordable to being affordable within budgets that Congress can approve. Phase-I technical work included a full scale (8 kW) Optical Mining demonstration using a high fidelity CI-type asteroid simulant in vacuum using sunlight from a 10 meter diameter solar concentrator without mechanical contact or down force. This work confirmed physics based mathematical model of the excavation and volatile extraction process and scalability of results from 36 prior, small scale (≈ 1 cm diameter) demonstrations and tests.

NASA NIAC Phase-II work will complete mission and system analysis of the application of Optical Mining to an exciting program of human exploration and will mature the technology of Optical Mining to the point at which NASA can baseline this approach for an affordable program of human exploration. The mission studies will address the production via Optical Mining missions to extract and retrieve resources, consumable processing, storage, and application of consumables to human exploration mission in cislunar, NEO and Martian space. Laboratory work will include the development and integration of a 30 kW Optical Mining test apparatus in the laboratory and integration with high quality vacuum chamber for a test program involving Optical Mining. Two mission concepts Phase-I & Phase-II to explore these capabilities have been selected as the first-ever Phase-III studies within the NASA Innovative Advanced Concepts (NIAC) program. This is to pursuing new technologies that could help make deep space exploration more Earth-independent by utilizing resources on the Moon and beyond. These NIAC Phase III selections are a component of that forward-looking research and we hope new insights will help us achieve more firsts in space. The Phase-III proposals outline an aerospace architecture, including a mission concept, that is innovative and could change what’s possible in space.

Possibilities

  • The optical-mining approach aims to excavate carbonaceous chondrite asteroid surfaces and drive water and other volatile materials out of the excavated material and into an enclosing, inflatable bag, all without the need for complex or impractical robotics.
  • After the asteroid has been encapsulated and de-spun, an inflatable solar concentrator churns out direct solar-thermal energy to the asteroid surface. This heat is used to excavate the asteroid and force the water to outgas into the enclosing bag. From there, the out gassing water is pumped into a passively cooled bag and stored as solid ice. The plan involves harvesting up to 100 metric tons of water from a near-Earth asteroid, and taking the material to lunar orbit or other depot locations.
  • The products of interest are volatiles, especially water which can be harvested from rock by a process called spalling, in which tiny, explosive pops of expanding gas drive out particles and gas.
  • Large solar furnaces can be used to shed light and heat onto the idea.  Since the late 1970s, researchers have used these furnaces to simulate the sudden heat generated by a nuclear explosion. The furnace makes use of two primary sets of mirrors. One large, flat set can pivot around to seize the rays of the sun and direct them though a shutter system onto the second set of mirrors, which, in turn, focuses the light and heat onto the target.
  • Tests could show that highly concentrated optical energy excavates the surface of material in a controlled way, analogous to how intense lasers can ablate surfaces, constantly exposing new material and forcing water out of the spalled material.

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