Space-Based Infrared Telescope for Planetary Defense Gets Boost from National Academies

Space-Based Infrared Telescope for Planetary Defense Gets Boost from National Academies

A report from the National Academies of Sciences, Engineering, and Medicine today gives a boost to supporters of building a space-based infrared telescope to detect asteroids as part of NASA’s planetary defense goals as opposed to its science program.  The distinction is important because NASA’s science program is guided by the Academies’ Decadal Surveys, which do not include missions for planetary defense, making it virtually impossible for such missions to compete for NASA’s limited mission opportunities.

Congressional interest in detecting and tracking Near Earth Objects (NEOs) — asteroids and comets — that could threaten Earth dates back to 1998.  At that time, Congress directed NASA to detect, track, catalog, and characterize 90 percent of NEOs 1 kilometer or greater in diameter within 10 years.  NASA succeeded and in the 2005 George E. Brown Near Earth Object Survey Act, Congress then directed the agency do the same for NEOs 140 meters or more in diameter within 15 years.

That 15 years is up next year, but NASA is not close to achieving that goal because it is difficult to find NEOs that small.  The question is what ground- or space-based systems are needed to do that.

NASA asked the Academies to assess various alternatives.  The study was conducted under the aegis of the Academies’ Space Studies Board (SSB) and chaired by Jay Melosh of Purdue University.   It concludes that a space-based infrared telescope is the answer.

NASA has been funding “Phase A” concept studies and technology development of such a telescope, Near-Earth Object Camera (NEOCam), at the Jet Propulsion Laboratory (JPL) for several years, but has not permitted it to proceed to “Phase B,” preliminary design and technology completion. The Principal Investigator (PI) is Amy Mainzer.

One complication is that such missions ordinarily must compete for funding within the Discovery series of mid-sized planetary science missions that NASA selects every 2-3 years.  NASA’s planetary science priorities are guided by Decadal Surveys conducted by the Academies every 10 years, but they explicitly exclude issues related to the hazards posed by asteroids.

The committee notes that NEOCam is primarily a planetary defense mission that has been forced to compete within NASA’s Discovery program against other proposals that have primarily scientific objectives. This has placed NEOCam and similar planetary defense-related missions at a competitive disadvantage.

Since “there is a bias against selection of planetary defense-focused missions” in the Discovery program, they should not be forced into that selection process.

Recommendation: Missions meeting high-priority planetary defense objectives should not be required to compete against missions meeting high-priority science objectives.

The report does not specifically recommend NEOCam, but suggests a separate Planetary Defense mission line be established with an announcement of opportunity focused on planetary defense requirements.

NEOCam already has supporters, though.

In April, NASA Administrator Jim Bridenstine gave the keynote address at the IAA Planetary Defense Conference and was asked about NEOCam.  Noting that he had been asked about NEOCam at a recent congressional hearing, Bridenstine said NASA is “committed to doing that” and he would consult with the head of NASA’s Science Mission Directorate and Planetary Sciences Division about how to fund it.

Artist’s illustration of NEOCam. Credit: NASA/JPL-Caltech

In its markup of the FY2020 appropriations bill for NASA, the House Appropriations Committee directed that NASA spend no less on NEOCam in FY2020 than in FY2019 pending the result of this report.

Linda Billings, a consultant to NASA’s Planetary Defense Coordination Office (PDCO), explained the history of the NEOCam program in a blog post today. She points out that PDCO is already funding the Double Asteroid Redirect Test (DART) and paying for NEOCam in addition would be problematical within PDCO’s current budget of about $160 million per year.

DART is scheduled for launch in 2021, so NEOCam may have to wait until a funding wedge opens up or Congress explicitly provides money for it.

NEOCam is currently in an “extended Phase-A” period. Advocates want it to move to Phase B.  Mainzer and PDCO head Lindley Johnson said at a media briefing prior to the Planetary Defense Conference that NEOCam has a life-cycle cost of $500-600 million, but could shorten the time needed to find 90 percent of NEOs 140 meters in diameter or greater from 30 years to 10 years.

At last week’s House Science, Space, and Technology Committee hearing on NASA’s science program, Mark Sykes of the Planetary Science Institute praised Mainzer’s work on NEOCam and an earlier asteroid-hunting mission, NEOWISE.  He applauded NASA’s decision to proceed with NEOCam, but that apparently was premature.  A NASA spokesman told that Sykes’s comment was based on a “miscommunication” and the agency has not made a decision about NEOCam’s future yet.

Meanwhile, the University of Arizona announced today that Mainzer will join the University’s Lunar and Planetary Laboratory as a professor of planetary science in the fall.

This article has been updated.

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