NASA Logo, National Aeronautics and Space Administration
Intelligent Systems Division Banner


Crewed NEO missions will put humans demonstrably on the way to Mars while producing exciting new science.

Constellation Program

Deep-space experience is critical to humanity’s expansion beyond the Earth-Moon system. A series of missions to NEOs, each one longer and more distant than the last, would provide essential mission experience for astronauts, mission operations, and Mars-class spacecraft systems. Such missions would be on par technically (though not in flight time) to visiting the Martian moons Phobos and Deimos. Longer NEO missions would be more Mars-like in terms of distance, time, and system performance.

constellation satellite

NEO missions would also provide an opportunity to develop and deploy the on-board mission planning, command, and control and semi-autonomous crew operations systems required by spacecraft operating in deep space. In situ resource utilization (ISRU) evaluations from NEO missions would help to validate or disprove the ideas for using asteroids as material resources. In addition to mineral resources. a significant portion of the NEO population may contain water, an attractive source of life support and fuel for future deep-space missions.

Science Return

Piloted missions to NEOs using the CEV will produce a great deal of technical and engineering data on spacecraft operations for future human space exploration. They will also provide the capability to conduct an in-depth scientific investigation of these objects. Essential physical and geochemical properties of NEOs can best be determined from dedicated spacecraft missions.


Although ground-based observations can provide general information about the physical properties of NEOs, spacecraft missions are needed for detailed characterizations and to obtain sample returns from ancient bodies radically different from the Moon and Mars. Such missions are vital from a scientific perspective for understanding the evolution and thermal histories of these bodies during the formation of the early solar system, and to identify potential source regions from which these NEOs originated.

A CEV-type mission will have a much greater capacity for science and exploration of NEOs than robotic spacecraft. On-board science capability will most likely include:

  • a high-resolution camera for detailed surface characterization and optical navigation
  • a light detection and ranging (LIDAR) system for hazard avoidance (during close proximity operations) and detailed topography measurements
  • a radar transmitter to perform tomography, enabling a detailed look at the interior structure of the NEO (which also may have implications for future hazard mitigation techniques)
  • the capability to precisely place and re-deploy relatively small scientific packages or in situ experiments on the surface of the NEO

A crewed mission has the added advantage of EVA for sample collection during close proximity operations. The ability for the crew to traverse and collect one or more macroscopic samples from specific terrains on the surface of an NEO is the most important scientific aspect of this type of mission.

astronaut working on satellite

Planetary Defense

NASA was directed by Congress in the 2005 Authorization Bill to report on options for deflecting an Earth-threatening asteroid. Many proposed deflection schemes critically depend on asteroid characteristics such as density, internal structure, and material properties – precisely the parameters that a crewed mission to an NEO could measure.

Massive asteroid hitting Earth

The CEV could also deploy a transponder to the surface of the object for a long-term study of the NEO’s orbital motion. This could be particularly useful for monitoring objects that have the potential for a possible future Earth impact.

Related Documents

Piloted Orion Flight Feasibility Study
Presented at AIAA Space 2007 Conference

Into the Beyond: A Crewed Mission to an Near-Earth Object
Text | Slides

Related NASA Sites

Near Earth Object Program Orion Crew Exploration Vehicle Vision for Space Exploration

First Gov logo
NASA Logo -