National Aeronautics and Space Administration
Washington, DC 20546-0001
July 31, 2018
Reply to Attn of: Office of the Chief Scientist
Dr. Fiona Harrison
Chair, Space Studies Board
National Academies of Sciences, Engineering, and Medicine
500 5th Street NW
Washington DC, 20001
Dear Dr. Fiona Harrison,
NASA’s 2005 authorization legislation directed the Agency to find 90% of all near-Earth objects (NEO) 140 meters or larger by the end of 2020—a total population most recently estimated to be about 25,000. It is now well known that a significant fraction of NEO’s have small albedos in the visible spectrum (primarily reflected light) and are bright in the infrared (IR) portion of the spectrum since the IR signature also contains the heat radiated by the asteroid. In the 2010 NAS report Defending Planet Earth: Near-Earth Object Surveys and Hazard Mitigation Strategies that committee found that “detections of potentially hazardous NEOs by an infrared telescope (one sensitive to infrared light) will result in a more accurate size-frequency distribution for these objects.” NASA chartered a team of experts in late 2015 to update estimates of what’s out there, what’s yet to be found, and assess the technology available to us today for detection. The science definition team stated that sufficient developments in infrared technology have occurred with the potential to significantly advance our ability to find and determine the size of near-Earth objects.
Statement of Task: The National Academies of Sciences, Engineering and Medicine will establish an ad-hoc committee to investigate the following and make recommendations:
- Explore the relative advantages and disadvantages of IR and visible observations of NEOs.
- Review and describe the techniques that could be used to obtain NEO sizes from an infrared spectrum and delineate the associated errors.
- Evaluate the strength and weaknesses of these techniques and recommend the most valid techniques that give reproducible results with quantifiable errors.
In order for NASA to be able to use the results of this study, NASA would like to receive the Academy’s findings within the second quarter of 2019. The technical point of contact
for this effort will be Dr. Louis Barbier and can be reached at or .
James L. Green
NASA Chief Scientist