A new method of mining asteroids for rocket fuel and water was successfully tested at White Sands Missile Range Nov. 13.
A team from the TransAstra Company led by founder and chief technical officer Dr. Joel Sercel used the solar furnace at WSMR's Survivability Vulnerability Assessment Directorate to test a method that may be used to mine asteroids for valuable water using the power of the sun.
The solar furnace uses a large heliostat, a mirror-covered panel that follows the sun, to reflect sunlight into a reflector that focuses the sun's energy onto a single spot about 6 inches in diameter. Normally the solar furnace is used for military testing, generating the kind of heat needed to simulate that of a nuclear blast.
"In this instance Dr. Joel is looking to place a solar reflector in outer space to create a similar hotspot. So we can use this facility to do this exactly like he would in outer space," said Stacey Hooley, an electrical engineer with WSMR's Survivability, Vulnerability Assessment Directorate.
Using a similar method TransAstra hopes to use the heat of the sun to mine asteroids by burning away material to harvest in a method called optical mining.
While using a solar furnace of this scale on earth can be a little tricky, as it's affected by wind, clouds, and the amount of sun you can get at a time of year, in space solar furnace like devices are much more efficient.
"Of course here on earth we have to wait for cloud cover and the wind, and in space you don't have to do that," Hooley said.
The plan is for an asteroid to be captured and secured in a large bag-like structure. Using a spaceborne version of the solar furnace, light from the sun would be focused onto a small point only a few inches across. The heat would cause the asteroid to heat up and expel material, which would be captured and the water extracted.
"So we will go out to an asteroid in deep space, capture maybe 100 tons of water from it, and then bring that water back to lunar orbit to a propellant depot, where it could supply astronauts and private sector industrial ventures," Sercel said.
While it may sound like deep science fiction, according to Sercel much of the technology has already been built and proven in other functional areas, allowing TransAstra's mining rig to be more about uniting and refining the technology to serve this new purpose.
To test this plan, Sercel placed a carefully crafted artificial asteroid into a vacuum chamber connected to a water trap. Fitted with a special quartz glass window designed to resist the high temperatures, the focused solar energy was then used to superheat the simulated asteroid, causing the water and other materials inside to explode outward from the rock in an effect called spalling. The water trap then captured the water. While the experiment had to be cut short after the glass window shattered while cooling back down after a shot, the water trap was able to collect a small amount of water. Sercel said even with the short run of the experiment, the fact that water was collected at all proved the basic mechanics worked, and Sercel believes that improving the process may be a simple matter of increasing the size of the water trap to increase its efficiency.
Water is one of the most valuable resources in space exploration. In addition to its requirement for drinking, it's also useful for dozens of other purposes including its ability to be broken back down into hydrogen and oxygen and used as rocket fuel.
"Initially we want to mine water and the next thing is carbon dioxide, and we do that because those are materials that are used up," Sercel said. "We can make propellant for rockets, breathable atmosphere, they can drink it if we purify it. Water makes an excellent radiation shield, so these will be the first things that we harvest from asteroids."
This is why the test is seen as such an important step in space colonization. Traveling to other worlds is extremely challenging as humans currently have to take nearly everything they need, including fuel into space with them. Getting the fuel needed for an interplanetary voyage into space is very difficult and expensive. It's hoped that finding ways to harvest and generate fuel in space will help reduce the cost of spaceflight by allowing spacecraft to burn only the fuel needed for the spacecraft, crew and payload to reach orbit at launch, and then refuel once in space, eliminating the costs associated with carrying an entire missions worth of fuel into orbit.
Using the solar furnace for a scientific mission instead of its usual military function is a change for the WMSR engineers, who had to adapt to the more dynamic methods of the civilian researchers.
"We work in a very adaptive way in the laboratory. We come in, things don't work as expected and we need to make changes," Sercel said. "The White Sands staff quickly adjusted, they are just amazing how fast they change the facility and work with us on this."
While WSMR, as an Army Test and Evaluation Command test center is geared toward military testing, supporting private and commercial testing is a common activity. Conducting tests of this kind are actually mutually beneficial, as it allows WSMR to maintain personnel and mission support levels, while providing an important service to customers that don't have the facilities and trained staff to conduct the test on their own.
"White Sands has many many facilities on this post that produce different environments, and when you have an entrepreneur that can't afford to build that facility themselves, we may have it," Hooley said. "There's thermal facilities, hot and cold, radiation facilities, all types of environments, high powered microwave, electromagnetic pulse... and that's just a few of the facilities we have here at White Sands."
Sercel likens TransAstra's use of the facilities on WSMR to the early days of the transcontinental railroad.
"The US government has a long partnership with private industry that results in fantastic new capability," Sercel said. "What we're trying to do at TransAstra is to build the transcontinental railroad of space. So we think the transportations systems we are building with this effort will make humanity a space faring civilization in the same way the transcontinental railroad brought us across North America."
Sercel hopes that the success of this initial test will allow them to return with improved systems and conduct another test next year.
Related Links:
The U.S. Army Test and Evaluation Command
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