Near-Earth Asteroids 2006 RH120 And 2009 BD: Proxies For Maximally Accessible Objects?Near-Earth Object Human Space Flight Accessible Targets Study(NHATS): http://neo.jpl.nasa.govnhats/. As of mid-July 2015: 1,434 of the 12,778 currently known NEAs are more astrodynamically accessible than is Mars (requiring less Delta v and or less flight time for round-trip missions). Within those 1,434 NEAs: 605 NEAs can be visited round-trip for less Delta v (9 km/s) than the lunar surface. 51 NEAs can be visited round-trip for less v (5 km/s) than low circular lunar orbit. NEO population statistical models:Tens of thousands of NEAs greater than 100 m yet to be discovered. At least several million NEAs less than or equal to100 m in size (down to approximately 3 m in size) yet to be discovered. How accessible are the NEAs that haven't yet been discovered?
Barbee, Brent W. (NASA Goddard Space Flight Center Greenbelt, MD United States)
Chodas, Paul W. (Jet Propulsion Lab., California Inst. of Tech. Pasadena, CA United States)