In a draft report dated 23 November 2015,NASA's Formulation Assessment and Support Team for the Asteroid Redirect Mission,a group of government and academic solar system exploration experts that provide timely inputs for mission requirement formulation,revealed that NASA has identified a reference target asteroid for the mission.It is known as Near Earth Asteroid 2008 EV5 (the 5 is formally rendered as a subscript numeral).Final target selection will be made approximately a year before launch.2008 EV5 provides a valid target that can be used to help with formulation and development efforts,so was the main NEA around which the FAST group focused its attention.2008 EV5 is about 400 meters in diameter and has a reflectance spectrum consistent with carbonaceous chondrite meteorites (meteorites are small pieces of asteroids or comets that enter the atmosphere and reach Earth's surface).
It is possible to identify 6 distinct candidate 10-m scale boulders for collection on 2008 EV5's surface by visual inspection of radar images.There are likely millions of 10-cm scale cobbles on 2008 EV5,and 3,000 1-5m boulders would be expected on the surface of 2008 EV5.One of the candidate boulders is located near the South Pole of the asteroid;the location of the others is uncertain at this time.
Radar observations show that 2008 EV5 has a top-like shape with an equatorial bulge.
Initial dynamic modeling indicates that 2008 EV5 began its existence as part of a much larger body in the Asteroid Belt (likely diameter greater than 100 km) and migrated inward across the inner main belt over many millions of years until it reached a planetary gravitational resonance that drove it into the NEA population.Besides robotic boulder collection,2008 EV5 will be used for an enhanced gravity tractor asteroid deflection demonstration (Earth defence).*
The ARM has two segments:the Asteroid Redirect Robotic Mission and the Asteroid Redirect Crew Mission.The ARRM mission is planned for an end of 2020 launch.The Solar Electric Propulsion-powered robotic spacecraft will intercept the asteroid,land on it and retrieve a boulder with its robotic arm,then fly the boulder to a Selenocentric Distant Retrogade Orbit at a height of 45,000 km above the Moon.In late 2025,the Orion spacecraft will be launched on the Space Launch System rocket to carry out the Asteroid Redirect Crew Mission and will rendezvous and dock with the robotic spacecraft.The 180-day crewed mission will entail spacewalking astronauts exploring the redirected boulder, collecting and packing samples of the boulder for return to earth.That high above the Moon,they will be farther out in space than any previous astronauts and,far from the Earth's protective Van Allen Belts,exposed to higher levels of solar and cosmic radiation,but have new spacesuits and spacecraft shielding to deal with that.Psychologically,they may be affected by how distant Earth will be-small enough to cover it with your thumb.*
Before all this,an uncrewed Orion mission,Exploration Mission-1,will be launched to the Moon on the SLS in 2018;and then the first Orion crewed mission,EM-2,to a lunar orbit.NASA's Orion program is an incremental deep space exploration process beginning in cislunar space and building to journeys to the Martian system,including the Martian moons Phobos and Deimos as well as Mars itself.The agency is welcoming international participation along the lines of the International Space Station,which is currently researching and testing solutions to the challenges posed by deep space exploration.