COLLEGE PARK, Md. — Scientists used an appearance by the NASA administrator at a conference April 29 to press him to fund additional missions that support the agency’s work in discovering and characterizing near Earth objects.

In an opening keynote at the Planetary Defense Conference here, NASA Administrator Jim Bridenstine said the agency was taking steps to identify objects that could pose an impact hazard to the Earth, but that there was more work it needed to do to achieve goals established by Congress years ago.

A provision in a 2005 NASA authorization act directed the agency to discover 90 percent of the near Earth objects at least 140 meters in diameter — enough to cause regional-scale devastation in the event of an impact — within 15 years. With a year to go, astronomers have discovered more than 8,500 such objects, but they estimate that is only about one-third of the total population.

“We’re only about a third of the way there and the law that has been passed says that NASA is required to be able to detect, track and characterize not just one third but 90 percent of them,” he said, “which means we have to use our systems, use our capabilities, to ultimately get a lot more data, and we have to do it faster.”

He noted that that one of the goals of a near Earth object strategy and action plan released by the White House’s Office of Science and Technology Policy last year is to improve detection of such objects. “We are working on that every day,” he said, adding it was something open to international cooperation. “We want more international partners that can join us in this effort. We want more systems on the face of the Earth that can detect and track these objects.”

However, past studies have concluded that, to achieve the goal of the 2005 legislation, as well as to detect the far larger numbers of near Earth objects that are smaller but still pose a hazard — the object that exploded above Chelyabinsk, Russia, in February 2013 was no more than 20 meters across — will require a space-based observatory. NASA has studied such a mission, called Near Earth Object Camera or NEOCam, for several years, including ranking it as a finalist in the most recent competition for Discovery-class planetary science missions.

NASA did not select NEOCam for development in that competition, but did provide funding to support continued work on an infrared instrument it would use. “We want to continue the effort so we’re ready when the budget does become available to get this space-based [infrared] capability,” said Lindley Johnson, NASA planetary defense officer, in a talk later at the conference.

Some scientists are advocating for getting that capability sooner rather than later. NASA’s overall funding of planetary defense has grown in recent years to $150 million in 2019, and NASA requested the same amount in its fiscal year 2020 budget proposal. Much of that funding is going to the Double Asteroid Redirection Test (DART), a mission scheduled for launch in 2021 to intercept a near Earth asteroid as a test of techniques that could be used to deflect objects that pose an impact threat to Earth.

DART received $98 million in fiscal year 2019, the peak year of its funding profile. “Within the NASA planetary defense program, we have a wedge that begins to open up after this year,” said Jason Kalirai, civil space mission area executive at the Johns Hopkins University Applied Physics Lab, which is developing DART.

That wedge provides an opening for NEOCam, mission advocates argue, and they believe it could be completed in time to take advantage of a cost-saving co-manifested launch with another NASA mission, the Interstellar Mapping and Acceleration Probe, in 2024. Meeting that deadline, though, would require starting work on the mission as soon as possible.

Asked about that at the conference, Bridenstine said he was interested but didn’t commit to a specific launch date. “NEOCam is on the agenda,” he said, noting that NASA currently has a limited space-based capability in the NEOWISE mission, a repurposed infrared astrophysics observatory. Bridenstine said he would talk to Thomas Zurbuchen, associate administrator for science, and Lori Glaze, director of the agency’s planetary science division, “about ultimately how to get that funded and fielded.”

Others at the meeting pushed for a mission to the near Earth asteroid Apophis, which will pass closer to the Earth in April 2029 than satellites in geostationary orbit. That flyby, they argued, presented a “unique opportunity” to study an asteroid that could be done outside of existing planetary science programs.

Bridenstine had a brief response to that proposal when it came up in in a question-and-answer session. “Awesome,” he said.

In a brief interview after his speech, Bridenstine said he supported in general the concept of having a budget line devoted to planetary defense missions, rather than having them compete for funding within NASA’s existing planetary science budget. “It’s not a bad idea,” he said, noting he would need to first discuss that concept with the White House’s Office of Management and Budget.

Exploration update

Most of Bridenstine’s speech at the conference was devoted to planetary defense, but he did discuss the agency’s exploration plans, including the goal of landing humans on the moon by 2024 established a little more than a month ago in a speech by Vice President Mike Pence.

That goal, Bridenstine said, will require the use of the Space Launch System despite delays in its development. “NASA is highly committed to this effort,” he said. “The only way to achieve that is to use this rocket, the biggest rocket that has ever been developed, the Space Launch System, and the Exploration Upper Stage.” However, the SLS, in its initial versions including the one with the Exploration Upper Stage, will fall short of the payload performance of the half-century-old Saturn 5.

Bridenstine added that SLS could also support space science missions and even planetary defense. “This rocket is an enabler for what you in this room are trying to achieve, which is the protection of planet Earth,” he said.

Achieving the 2024 goal announced by Pence last month requires additional funding, and Bridenstine previously said that he would work with the White House to develop a revised budget request for fiscal year 2020 with the additional funding needed. Asked in the interview if that request had been submitted to Congress, he replied, “Not yet.”

Bridenstine is currently scheduled to testify May 1 before the commerce, justice and science subcommittee of the Senate Appropriations Committee on the agency’s 2020 budget request.