280 likes | 463 Views
Asteroid Mining Concepts. Shen Ge. Near-Earth Asteroids. Near-Earth Asteroids (NEAs) of interest due to the relative ease of reaching them. All NEAs have distances of less than 1.3 AUs. Images from William K Hartmann. Known Near-Earth Asteroids. Data from JPL. Asteroid Resources.
E N D
Asteroid Mining Concepts Shen Ge
Near-Earth Asteroids • Near-Earth Asteroids (NEAs) of interest due to the relative ease of reaching them. • All NEAs have distances of less than 1.3 AUs. Images from William K Hartmann
Known Near-Earth Asteroids Data from JPL
Asteroid Resources Chart from Charles Gerlach
Important Questions Asteroid Composition Mining Technologies Economic Analysis Astrodynamics and Propulsion
What resources do NEAs offer? C-type Carbonaceous (water, volatiles) S-type Stony (silicates, sulfides, metals) M-type Metallic (metals)
Required Asteroid Mining System Chart from Brad R. Blair and Leslie S. Gertsch
How do we get there? • We want to find the asteroids with low delta-vs to reduce propellant needed. Distribution of specific linear momentum of a Hohmann transfer from low Earth orbit (LEO) to NEAs according to Benner. 1st WARNING: For Virgil and other non-science or engineering majors who apparently gets a headache from seeing equations, please turn your head away from the next slide.
Rocket Equation where Δv = velocity change Ve = exhaust velocity Mo = total mass Mp = propellant mass TwoOptions: • Reduce delta-v required for trajectories to enable low-thrust propulsion methods such as electric, solar thermal, or solar sail propulsion. • Use chemical propulsion for high thrust trajectories if needed.
Example of a Hohmann Transfer “Apollo-Type” Mission
Low Delta-vs for Many NEAs Compare!
Interplanetary Superhighway Low delta-v trajectories combined with electric or solar propulsion can open the pathway to many more asteroids previously considered impossible to reach.
Or maybe bring the asteroid here… • Use gravity assists to bring candidates into a stable orbit around Earth or • Modify orbits of temporarily-captured objects (TCOs) to make them stable orbits. Diagrams from Mark Sonter
Can we justify the costs? • The economic justification for an asteroid mining operation is only the case if the net present value (NPV) is above zero. • It is NOT just the cost of mining and going there versus the profit obtained from resources. • Sonter has done extensive work in creating a formula for these calculations. 2nd WARNING: For Virgil and other non-science or engineering majors who apparently gets a headache from seeing equations, please turn your head away from the next slide.
Sonter’s NPV Equation • Corbit is the per kilogram Earth-to-orbit launch cost [$/kg] • Mmpe is mass of mining and processing equipment [kg] • f is the specific mass throughput ratio for the miner [kg mined / kg equipment / day] • t is the mining period [days] • r is the percentage recovery of the valuable material from the ore • ∆v is the velocity increment needed for the return trajectory [km/s] • ve is the propulsion system exhaust velocity [km/s] • i is the market interest rate • a is semi-major axis of transfer orbit [AU] • Mps is mass of power supply [kg] • Mic is mass of instrumentation and control [kg] • Cmanuf is the specific cost of manufacture of the miner etc. [$/kg] • B is the annual budget for the project [$/year] • n is the number of years from launch to product delivery in LEO [years].
Expectation Value of NPV • NPV should take into account the risk of failure. Exp NPV = p x NPV where p = fractional probability of outcome
The Next Steps • Asteroid Composition. Create database of NEAs of interest for resource extraction with their orbits and compositions. • Space Mining. Develop potential mining technologies for modified use in space. • Astrodynamics. Design optimal trajectories and propulsion methods to go there and back. • Space Economics. Identify costs and returns as well as potential investors.