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NEO Survey and Deflection Analysis and Alternatives

Report to Congress, March 2007

  • The final report is avilable as a PDF document
  • The working copy of the NEO study is also available as a PDF Document
  • The following is the report summary only.


Section 321 of the NASA Authorization Act of 2005 (Public Law No. 109-155), also known as the George E. Brown, Jr. Near-Earth Object Survey Act, directs the NASA Administrator to transmit an initial report to Congress no later than one year after the date of enactment that provides: (1) an analysis of possible alternatives that NASA may employ to carry out the survey program of near-Earth Objects (NEO), including ground- based and space-based alternatives with technical descriptions; (2) a recommended option and proposed budget to carry out the survey program pursuant to the recommended option; and (3) an analysis of possible alternatives that NASA could employ to divert an object on a likely collision course with Earth.

The objectives of the George E. Brown, Jr. NEO Survey Program are to detect, track, catalogue, and characterize the physical characteristics of NEOs equal to or larger than 140 meters in diameter with a perihelion distance of less than 1.3 AU (Astronomical Units) from the Sun, achieving 90 percent completion of the survey within 15 years after enactment of the NASA Authorization Act of 2005. The Act was signed into law by President Bush on December 30, 2005.

A study team, led by NASA’s Office of Program Analysis and Evaluation (PA&E), conducted the analysis of alternatives with inputs from several other U.S. government agencies, international organizations, and representatives of private organizations. The team developed a range of possible options from public and private sources and then analyzed their capabilities and levels of performance including development schedules and technical risks.

Key Findings for the Survey Program

Key Findings for Diverting a Potentially Hazardous Object (PHO)

The study team assessed a series of approaches that could be used to divert a NEO potentially on a collision course with Earth. Nuclear explosives, as well as non-nuclear options, were assessed.

Alternatives Considered to Detect, Track, Characterize, and Deflect/Mitigate NEOs

The following tables provide a summary of the options considered. Technical descriptions of each option, as well as other combinations of alternatives, can be found in subsequent sections of this report. For each option, Table 1 shows the percentage of PHOs that would be found by the survey by the end of 2020 and the year each option would achieve 90 percent completion, starting with the option of sharing the use of potential ground-based observatories, which will be referred to as the “Reference” architecture through the rest of this document. Details regarding the availability of assets for each option are also found in subsequent sections. Table 1 shows that individually each of the first three options fall short of meeting the Congressional goal. As shown in the last line of Table 1, the minimum survey architecture that achieves the goal would be a combination of the shared ground-based assets plus one of two dedicated asset options.

Currently, NASA carries out the “Spaceguard Survey” to find NEOs greater than 1 kilometer in diameter, and this program is currently budgeted at $4.1 million per year for FY 2006 through FY 2012. We also have benefited from knowledge gained in our Discovery space mission series, such as the Near Earth Asteroid Rendezvous (NEAR), Deep Impact, and Stardust missions that have expanded our knowledge of near-Earth asteroids and comets. Participation by NASA in international collaborations such as Japan’s Hayabusa mission to the NEO “Itokawa” also greatly benefited our understanding of these objects. NASA’s Dawn mission, expected to launch in June 2007, will increase our understanding of the two largest known main belt asteroids, Ceres and Vesta, between the planets Mars and Jupiter. NASA conducts survey programs on many celestial objects - the existing Spaceguard program for NEOs, surveys for Kuiper Belt Objects, the search for extra-solar planets, and other objects of interest such as black holes to understand the origins of our universe. Our Discovery mission series in planetary science may offer additional opportunities in the future beyond our current survey efforts.

NASA recommends that the program continue as currently planned, and we will also take advantage of opportunities using potential dual-use telescopes and spacecraft - and partner with other agencies as feasible - to attempt to achieve the legislated goal within 15 years. However, due to current budget constraints, NASA cannot initiate a new program at this time.