Terra, Aura, Aqua
NASA will invite the Terra, Aura and Aqua missions to the upcoming senior review of extended Earth science missions, but warned the agency does not have enough funding to support every mission seeking an extension. Credit: NASA

WASHINGTON — NASA will allow three aging Earth science missions to participate in an upcoming senior review of extended missions even as the agency warns of budget pressures on its overall portfolio of missions.

During a town hall Dec. 15 at the Fall Meeting of the American Geophysical Union, NASA officials said they agency had invited the Aqua, Aura and Terra missions to submit proposals in the 2023 senior review of Earth science missions that are in their extended phases.

The three spacecraft, launched between 1999 and 2004, remain functional but are running low on stationkeeping propellant. The spacecraft have started to drift from their original operational orbits, which prompted concerns about impacts on the science they can perform and data continuity.

Julie Robinson, deputy director of NASA’s Earth science division, said the agency collected feedback about those missions through a request for information and a virtual workshop in November attended by more than 500 people. “One outcome of that is that Terra, Aqua and Aura will be invited to the senior review,” she said. In a senior review, missions that have completed their original prime missions make the case for continued funding to extend their missions.

Being invited to the senior review, though, is no guarantee that the missions will be able to secure funding. Robinson said the upcoming senior review will be particularly challenging given limited funding available for mission extensions.

“The senior review is not going to be an easy one this year,” she said. “We don’t have the money in the budget to extend every mission that comes to the senior review.” The agency will ask the panel that reviews the mission to advise it on various trades it can make among the missions.

NASA requested more than $2.4 billion for Earth science in its fiscal year 2023 budget proposal. However, the omnibus spending bill enacted in late December provided just under $2.2 billion for Earth science. While that is an increase of $130 million from 2022, it comes as NASA is ramping up work on its line of Earth System Observatory missions and other projects.

At the town hall, one scientist said it was “pretty shocking” that NASA would even consider not extending those three missions given their performance and the community of researchers using data from them. Robinson again turned to financial challenges facing the overall Earth science program.

“In the case of Terra, Aqua and Aura, one of the challenges we have is that these systems, because they’ve been operating so long, they’re really expensive,” she said. NASA’s fiscal year 2023 budget request projected spending $30.7 million each on operations of Terra and Aqua and $20.5 million on Aura. One part of the senior review will be to look at reducing those operating costs, but she did offer an estimate of the range of potential reductions.

Those efforts come as NASA grapples with potential cost increases with the Earth System Observatory, notably the Atmosphere Observing System (AOS). An independent review found that AOS as currently designed is likely to cost $2.4 billion, $500 million more than NASA’s own estimate. That could force NASA to scale back or replace two AOS instruments.

“There are really painful trades in Earth System Observatory. There are also painful trades in deciding how much money to put on extended missions and how to operate them,” she said. “I can promise we will never make everybody happy with those trades.”

Jeff Foust writes about space policy, commercial space, and related topics for SpaceNews. He earned a Ph.D. in planetary sciences from the Massachusetts Institute of Technology and a bachelor’s degree with honors in geophysics and planetary science...