A submarine to explore the seas of Titan, hedgehog robotic explorers, asteroid wranglers, and even comet hitchhikers – all of these sound like they came out of the pages of a science fiction novel, right? Well these are actually just a few of the innovative concepts funded by NASA’s Innovative Advanced Concepts (NIAC) fellowship program. The program transforms technically credible innovations from science fiction to science fact.
Until recently, the concept of asteroid mining has been one of science fiction. Several companies like Planetary Resources are currently working to tap into the mineral resources on near-Earth asteroids. With hundreds of thousands of small asteroids in the Solar System, they could host a wealth of minerals and volatile material we could use on Earth. But that’s not all. Thanks to an innovative technique currently under development, asteroids could one day supply the resources we need to make fuel and even habitats in outer space.
The game-changing technique, called "optical mining," could allow us to tap into potential water reservoirs on asteroids without complex robotics. Water that, in turn, could be turned into fuel for the spacecraft, thus significantly reducing the cost of spaceflight. The concept of optical mining – also known as the Asteroid Provided In-Situ Supplies plan, or Apis – has been funded thanks to a NIAC fellowship and a small business contract.
Asteroids are basically cosmic leftovers: primordial chunks of rock and dust laced with metals, ices, and even tar. There are different varieties of asteroids, each with their own composition. Dark, carbon-rich “C-type” asteroids have massive amounts of water locked up in hydrated clay minerals, and would make the perfect targets for Apis.
Water is crucial to survival, but takes a lot of energy and money to get to space. So, utilizing water already in space would help reduce mission costs. Water can also be broken down into its constituent parts: hydrogen and oxygen; a huge benefit since both can be used to make rocket fuel.
Apis principal investigator Joel Sercel and his team plan to harvest water and other volatile materials from the surface of C-type asteroids or primitive meteorites called carbonaceous chondrites. The excavated material would go directly into an inflatable bag for storage. The Apis team hopes to reap as much as 100 metric tons of water from a near-Earth asteroid before transporting it to designated "depots."
Sercel and his team have performed lab experiments as well as computer simulations on meteorite samples and the results are promising. The team will use a large solar furnace at White Sands Missile Range in New Mexico for proof-of-concept testing in the coming months. The furnace uses two primary sets of mirrors to simulate the heat produced from a nuclear explosion. Sunlight is first collected by a large flat set of mirrors and then concentrated on the target with the second set. The team will test their idea on melon-sized asteroid simulants and expects the highly-concentrated light will dig through surface material, extracting volatiles from the rock via a process called spalling – where material is extracted as tiny pockets of expanding gas pop.
"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," Sercel told Space.com. "We believe that highly concentrated sunlight can drill holes, excavate, disrupt and shape an asteroid while the asteroid is enclosed in a containment bag."
As part of the Apis plan, up to 120 tons of water can be collected over several months and safely stored in the containment bag before being transported to lunar orbit.
