Improving weather forecasts, predicting sea-level rise, and understanding ecosystem change top a new list of priorities for future US Earth-observing satellites.
The US National Academies of Sciences, Engineering, and Medicine released the much-anticipated report on 5 January. It is likely to shape the future of Earth-science missions at NASA, the National Oceanic and Atmospheric Administration (NOAA) and the US Geological Survey for the next decade. More immediately, it provides scientists and agency leaders with ammunition to argue for Earth-observing research at a time when the White House and some members of Congress are looking to slash it.
“This is a very important process, having the community speak up and come up with a consensus set of priorities,” says Antonio Busalacchi, president of the University Corporation for Atmospheric Research (UCAR) in Boulder, Colorado. “Congress reads these, staffers read them, agencies pay attention in a very serious way.”
Focus on benefits
Unlike the last ‘decadal survey’, released in 2007, the new report focuses on science questions that need to be answered, rather than prioritizing particular spacecraft designs. It underscores how the data collected by Earth-observing missions benefit society and national security, from farmers who rely on drought assessments to the US military, which uses NASA and NOAA satellite data to plan its operations.
“Earth information is a critical part of our lives,” says Waleed Abdalati, director of the Cooperative Institute for Research in Environmental Sciences (CIRES) in Boulder, and co-chair of the group that wrote the report.
The analysis identified 35 key scientific questions to answer, including understanding how the planet’s water cycle is changing, learning why powerful storms occur where and when they do, and reducing the uncertainty in projections of future warming. It identifies aerosol particles, clouds and changes in mass across Earth's surface as among the most important environmental variables to study.
“I definitely think they did the right thing,” says Steven Nerem, an expert in satellite-based Earth measurements at CIRES. “We’re doing this for science, and how science will benefit society. With those things you make different decisions about which missions you might prioritize.”
NASA used the 2007 decadal survey as a blueprint for deciding what Earth-science instruments and missions to pursue. Tight budgets meant that many of the projects never came to pass, while others were delayed for years. (The ICESat-2 mission to measure polar ice sheets, which the 2007 survey recommended launching between 2010 and 2013, is now slated to go up in September.)
The latest report recommends that NASA establish a ‘designated’ category of missions in the next decade to observe the highest-priority variables. It calls for the agency to develop five of these spacecraft, with two capped at $800 million each, and the remaining three at $650 million, $500 million and $350 million, respectively.
The analysis also suggests funding three ‘Earth System Explorers’, at no more than $350 million apiece, to address the second tier of priorities — such as monitoring the levels of greenhouse gases in the atmosphere, and how much melting glaciers and ice sheets contribute to sea-level rise. And it recommends continuing the small-scale Earth Venture programme with two missions of $150 million or less.
NASA currently spends just under $2 billion a year on its Earth-science division, although the White House has proposed cutting that to $1.75 billion. The agency is planning to launch more than 15 Earth-science missions and instruments by 2023. Some of those already satisfy priorities laid out in the latest report, such as the planned launch — no earlier than March — of the next pair of US–German GRACE satellites. The probes are designed to measure variations in gravity to calculate shifts in mass on the Earth’s surface, such as those that occur when ice sheets melt. Other priorities, including the monitoring of aerosol levels, are not addressed by planned missions, says report co-chair Bill Gail, co-founder of the Global Weather Corporation in Boulder.
The report's authors say that NASA could implement their recommendations by working new missions into its future budgets, for a total of $3.4 billion over the next decade. “We think it can be done, but it requires diligence on the part of the agency to be sure there isn’t creep in scope or cost,” says Abdalati.
NOAA is working to set priorities for satellites that monitor weather on Earth and in space. The agency's preliminary findings will be presented next week at a meeting of the American Meteorological Society in Austin, Texas. "There was one clear area of overlap," says Richard Anthes, president emeritus at UCAR. Both the NOAA study and the decadal survey recommend developing a mission to study atmospheric winds in three dimensions to improve weather forecasts.
These priority-setting exercises are meant to prod researchers into new ways of thinking about how to study the Earth from space. “Ten years from now, I want people to be able to look back and say, ‘that really did push us to be innovative and creative in the way we approached pressing Earth-science problems’,” Abdalati says. “‘In ways that allowed us to do more than we otherwise could have.’”