Clark R. Chapman

1. http://www.boulder.swri.edu/clark/clark.html NEO IMPACT SCENARIOS The B612 Near-Earth Asteroid Mission Clark R. Chapman Southwest Research Institute Boulder, Colorado, USA, and “The B612 Foundation” Clark Chapman, Dan Durda & Rusty Schweickart Session 3-PD-3 “Threats & Consequences II” AIAA-2004-1416 Southwest Research Institute and B612 Foundation 2004 Planetary Defense Conference: Protecting Earth from Asteroids Garden Grove CA USA 23 February 2004 Objectives: “To move a ~200-meter NEA in a controlled manner and to comprehensively study the physical, geological, and compositional properties of several diverse NEAs in the 2015-2020 timeframe.” Presentation to the SSB Prometheus Solar System Exploration Panel Woods Hole, MA 21-22 June 2004

2. B612 Mission Objectives and Description: Learn by Doing! • Robust exploration of Near-Earth Asteroids for science, resource utilization, and hazard protection • NEAs link the primordial main-belt asteroidal parent bodies to laboratory study of meteorites • NEAs provide a far richer variety of very accessible materials for utilization in space than does the Moon • Demonstrates our capability to address popular concerns about a genuine natural hazard • Takes advantage of the thrust and power capabilities of Prometheus in the “New Vision” era of exploration • Explores and moves a ~200 m C-type NEA…then leaves to rendezvous with and explore other types • Thorough stand-off remote-sensing study of target • Deploys lander science package/s, docks near pole • Thrust with active attitude control (main engine gimballing) for several months • Scientifically explores and tries docking with M-type and other NEAs (moving them not necessary) • Sample return option Carbonaceous Chondrite Prometheus-based B612 mission Little Prince’s asteroid B612

3. Attaching to the Target NEA • Articulated arms may serve as a “net” to encompass object with less concern about strength of surface – but this is a challenge! • The “Ed Lu Tractor Beam” approach [lower right] utilizes gravitational attraction of NEA to spacecraft, with no attachment necessary (most efficient for objects a couple hundred meters in size; massive Prometheus-like spacecraft is good) • Concern in all approaches not to disrupt a weakly cohesive body

4. Moving the Target NEA • Several operational schemes have been considered • must deal with the spin • accelerate along track • may push or pull • A fraction of 1 cm/sec delta-v achieved over few months De-spin and thrust Analyses by D.J. Scheeres and R.L. Schweickart (AIAA 2004-1446) Push and torque

5. B612 Science Objectives “Impact Threat – cataloguing and classification of near-Earth objects; estimation of the recent impact flux and its variations; flux variation with position in solar system; hazard avoidance and mitigation.” -- from “A National Science Research Agenda” on Origins, Evolution, and Fate: The “Aldridge Commission Report”, June 2004 • Understand physical, chemical, geological processes that have affected C-type (and its parent) since origin • For target (& satellite/s): size, shape, mass, spin state, global optical traits for calibration, internal structure • characterize and map the surface geology: topography, craters, lineaments, rocks, “ponds”, texture, etc. • mineralogical/chemical composition of units • geological context for derivation of meteorites • intensive compositional, physical, and microscopic examination of localities • Learn about compositional and structural diversity of asteroidal fragments (& dead comets) by remote-sensing investigations of several other NEA types • Evaluate NEA properties relevant to practical issues • impact consequences; attachment for deflection • feasibility of documented scientific sampling for return • evaluation of approaches to mining for in-space use “…the Commission heard testimony that skills honed in implementing the vision could help detect and deflect harmful asteroids that could one day threaten Earth. Just recently the subject of science fiction novels and movie thrillers, such capability is now the focus of legitimate scientific investigation.”

6. Strawman Instrument Payload • Remote-sensing • Imaging • Vis/IR reflection spectroscopy (mapping) • X-ray, gamma-ray • Magnetometer • Active-sensing • Laser-ranging altimetry • High-power radar sounder • In situ landed measurements • Microscopic imaging • Soil/rock mechanics devices • Spectrometers (Raman, Mössbauer, XRF) • Scanning Electron Microscope & PA

7. B612 Mission: Concluding Comments • Thorough exploration of several NEAs motivated by science, potential utilization, and planetary defense – learn by doing! • Science instruments unfettered by usual mass and power constraints – learn about asteroids more nearly the way a terrestrial geophysicist learns about the Earth. • Finally explore the full diversity of primordial and evolved materials in small bodies – every small body visited so far has been unique…let’s understand the whole zoo. • An exciting mission that can engage several scientific disciplines and the general public – NEAs are not only vital scientifically, they pose a danger and they may be stepping stones to Mars.