NEXT WEEK, the Senate is set to spend considerable time figuring out how to pay for renewing an old campaign gimmick — keeping interest rates for certain federally backed student loans extra low at 3.4 percent. Doing so would be expensive; it would cost the government $6 billion to extend those low rates for just one year. That might not seem like much compared with the entire federal budget, but at a time when Congress has put tight limits on discretionary spending, many other, more worthy programs are fighting for every dollar.

Such as? The National Research Council (NRC) reported Wednesday that the U.S. system of earth observation satellites is “beginning a rapid decline” and is “at risk of collapse.” Already, the network of satellites that NASA and the National Oceanic and Atmospheric Administration (NOAA) use to monitor weather and climate relies on instruments that are operating beyond their intended use or long past their expiration dates. They will eventually run down their batteries or otherwise fail. The NRC reckons that the country could be left with as little as a quarter of its current number of earth observation satellites by 2020.

At major risk over the next decade are systems to measure Earth phenomena such as ocean winds or the planet’s radiation budget — essentially, how much energy is coming from the sun and how much is reflected back. NOAA is already facing the possibility of a fiscally induced gap in its polar-orbiting satellite coverage, without which it would have been difficult to forecast Washington’s “snowmageddon” blizzard, and other satellite programs are even more starved for support. Losing capacity to track climate trends, meanwhile, risks shattering critical databases recording how the Earth’s systems operate — and how humans are affecting them.

The reasons for this outlook are many — some overspending on certain projects to the harm of others, costly congressional mandates that diverted resources, and a recent rocket accident. Even if those factors were ignored, says Dennis Hartman, the chair of the panel that produced the report, agency budgets would still be too low to keep the country’s earth observation system in reasonable shape. The NRC proposes restoring NASA’s earth observation satellite funding to the level seen in the late 1990s — before President George W. Bush reprogrammed money from those satellites into things such as manned spaceflight to Mars. That level stands at about $2 billion.

Unfortunately, the satellites haven’t found a way to work themselves into the presidential campaign.