WASHINGTON — NASA’s small but high-profile planetary defense program has overcome disruptions caused by the coronavirus pandemic to continue searching for potentially hazardous near Earth objects.
NASA’s Near Earth Objects (NEO) Observations Program supports a variety of primarily ground-based efforts to discover, track and characterize NEOs. Those efforts, though, were slowed for a time by the pandemic, which temporarily closed observatories in the United States and other countries.
“We did see a number of observatories that had to close, either on their own or because their host organizations or host observatory sites had to close,” said Kelly Fast, manager of the NEO Observations Program, during a June 3 “Asteroid Day” webinar hosted by the Association of Space Explorers.
She said the program hit an “extreme point” in terms of the number of observatories closed in late March, but since then some observatories have found ways to resume at least partial operations with new COVID-19 safety protocols. That’s included the Catalina Sky Survey in Arizona as well as telescopes at Mauna Kea Observatory in Hawaii.
The closures did not significantly affect the number of new NEOs discovered. “It is a concern, but we’ve been watching the statistics at the Minor Planet Center, what’s being received there, and between what’s coming in from the NASA efforts and around the world, we’re doing OK,” she said.
Fast said that more than 2,400 NEOs were discovered by various search efforts in 2019. Through early June of this year, 1,222 had been found.
That observation effort is part of the NASA’s planetary defense program, a relatively small part of the agency with an annual budget of $150 million. However, its effort to search for any asteroids that might pose an impact risk to the Earth gives the program a much higher public profile. Public opinion surveys have often ranked that program as a higher priority among the general public than some of NASA’s far larger exploration efforts.
The program’s budget also funds NASA’s first dedicated planetary defense mission, the Double Asteroid Redirection Test (DART). That spacecraft will fly to the near Earth asteroid Didymos and collide with a small moon orbiting the asteroid in September 2022. Planetary scientists then plan to measure the change in the moon’s orbit caused by the impact to better understand the effects of the “kinetic impactor” technique that could be used to change the orbit of an asteroid threatening to impact Earth.
DART remains on schedule for launch in July 2021 on a Falcon 9 despite the pandemic, said Elena Adams, mission systems engineer for DART at the Johns Hopkins University Applied Physics Lab, which is managing the mission, during the webinar. The spacecraft bus, with its electric propulsion systems installed, recently arrived at the lab for integration and testing.
NASA plans to follow up DART with a second space mission, the NEO Surveillance Mission (NEOSM). That will deploy a spacecraft called NEO Surveyor at the Earth-Sun L-1 Lagrange point that will be used to search for NEOs using a small telescope and infrared detectors.
NASA announced in September 2019 that the mission, previously known as NEOCam and a finalist in an earlier round of the agency’s Discovery program of planetary science missions, would proceed as a “directed” mission within the planetary defense program. Agency officials said it made sense for NEOSM to be a directed mission since its primary goal — detect at least 90% of NEOs at least 140 meters in diameter — was established by Congress in a 2005 NASA authorization bill.
Amy Mainzer, a University of Arizona planetary scientist and survey director for NEOSM, said at the Asteroid Day webinar that the mission is working to reach a programmatic milestone known as Key Decision Point B in the fall, after the completion of a series of reviews.
In a separate presentation June 1 at a meeting of NASA’s Small Bodies Assessment Group (SBAG), Mainzer said a launch date for the mission depends on the funding profile. “If we are able to achieve an optimal funding profile,” she said, “we would be able to launch in the year 2025.” That profile would require NEOSM receiving about $90 million in fiscal year 2021, but NASA’s budget request for 2021 released in February did not spell out a specific funding amount for the mission. That request had only $83.6 million available in the planetary defense program for both space missions other than DART as well as ground-based searches and other analysis efforts.
Having a space-based telescope like NEOSM would have eased some of the pressures on the program caused when the pandemic closed observatories. Fast, speaking at the SBAG meeting, noted that NASA and others have conducted exercises in the past about how they would respond to an approaching asteroid. Those exercises didn’t include the possibility of observatories being shut down by a pandemic, she said. “We’ve never layered our disasters.”