Mining Thousands of Tons of Space Ice with Queen Bee
Five-thousand tons of water-ice delivered to cislunar space per two-year mission! In a recent announcement, TransAstra Corporation proposed a spacecraft able to achieve this. They call it the Queen Bee, a new part of the Asteroid Provided In-Situ Supplies (APIS; Apis) architecture. Queen Bee is a large scale version of their asteroid mining spacecraft design.
TransAstra is a Los Angeles, California based aerospace company founded in 2015 by Joel Sercel. Their goal is to help make industrial processes in space possible. A key process they study is extracting volatiles, including water, from small Near Earth Asteroids (NEA). Their past work has focused on Optical Mining, asteroid encapsulation, and solar thermal thrusters for the mining and utilization of carbonaceous Near Earth Asteroid (NEA) volatiles.
The Apis architecture and its enabling technologies have received significant research focus by TransAstra. This includes a successfully completed NASA Innovative Advanced Concepts (NIAC) Phase I with report, and the start of a two year Phase II effort that was awarded in 2017. Though this article focuses on mining vehicles, the Apis architecture has many other elements such as a reusable deep space tug and a consumables depot.
The name Apis comes from the genus name of honey bees. All architecture elements have a name related to bees, including aptly named Queen Bee. The purpose of the overall system is to create a reusable and economically sustainable space transportation network which can remove the need for expensive launches of fuel and water into space from Earth. The result of this is lowered costs for all space efforts including exploration, science, and settlement.
The way in which Queen Bee and the other mining vehicles work is through asteroid encapsulation, mining via the concentration of sunlight to induce spalling, and the collection and subsequent cryo-storage of released volatiles. The asteroids targeted for this process are mostly carbonaceous chondrite NEAs. This is because carbonaceous chondrites usually contain a high concentration of water and NEAs are both abundant and locationally convenient.
Inflatable structures are an enabling technology for these asteroid mining systems since they allow the system to be launched into space in a small stowed configuration that can then expand to full size after arrival. Because of this utility, inflatable structures are widely used in both Queen Bee and its smaller sibling Honey Bee. The way inflatable structures are used allows a comparatively small payload to contain a far larger system including large solar concentrators, bags for volatiles and spall material, and a large asteroid encapsulation bag.
To break up the captured asteroid the mining vehicle uses the Optical Mining process which involves the concentration of sunlight onto a focused region of its rocky surface. Repeated short applications of concentrated light are reflected onto the asteroid which heats the top surface layer of material and its trapped volatiles. Applied heating leads to thermal stress fractures in the material’s surface layer and outgassing of trapped volatiles. Released gaseous volatiles then propel away fractured particles of the asteroid in a process called spalling. The resultant spall particles and outgassed volatiles are then captured and stored separately.
When a captured asteroid is fully spalled for its volatiles, the mining vehicle utilizes the volatiles it extracted as propellant for its journey back to Lunar Distant Retrograde Orbit (LDRO). The trip back is powered by a solar thermal thruster called Omnivore. The Omnivore thruster superheats the volatile propellant by redirecting focused light from the same inflatable solar concentrators used to focus light for the asteroid spalling process. In the case of the smaller Honey Bee system, a 10 meter asteroid could produce 100 tons of volatiles during one mission. To return these resources to LDRO the mining vehicle would then use 10-20% of collected volatiles as Omnivore’s propellant, if the bagged spall material was left behind. If it were desired to return the captured spall material, the propellant cost would increase to 50-65% of captured ices.
For the case of the large Queen Bee system, a massive 5,000 tons of volatiles could be returned from processing a 40 meter class asteroid. This system would launch to space in a highly collapsed configuration sized to fit in the 9m (30ft) diameter payload of a super heavy class rocket such as Starship (currently being developed by SpaceX). Once deployed, Queen Bee would be capable of six two-year missions, that in total would return around 15,000 tons of volatile ices to cislunar space.
Before the demand for volatile ices in space necessitates usage of the Queen Bee, the far smaller Honey Bee system will be used. The Honey Bee is sized to fit within a 5.2m (17ft) diameter payload fairing and will be capable performing three missions that each return 100 tons of volatiles. With that capability in mind it is interesting to know that Joel Sercel of TransAstra stated that he believes the Honey Bee system, if used in a three vehicle fleet, will be fully capable of supplying the volatiles demanded by the next decade of space exploration and development.
But what is happening now and what is planned to happen next? Currently the focus of the Apis development roadmap is on refining the necessary Optical Mining technology. The next step will involve an orbital technology demonstrator called Mini Bee which was announced on January 20, 2019. The Mini Bee demonstrator will be TransAstra’s first space mission. It will utilize two SmallSats and a synthetic asteroid to demonstrate the capture, mining, and usage of mined volatiles for propellant thrust in space.
As we have seen, the future is exciting for space mining and the coming years will see great new strides made!
Asteroid Provided In-Situ Supplies (APIS), NIAC Phase I Final Report, Joel Sercel, https://drive.google.com/file/d/1tVUQJT5dtSOzPL2vB5u8mau46dmZphNM