There is a saying that luck is what happens when preparation meets opportunity, and it applies to scientists in Britain and the United States who are working on lower-cost versions of two Earth science missions that were derailed by their price tags. 

Both missions, the United Kingdom’s Traceable Radiometry Underpinnings Terrestrial and Helio Studies (TRUTHS) and the U.S. Climate Absolute Radiance and Refractivity Observatory (CLARREO), would make measurements that scientists agree are important to understanding climate change. It is clear, however, that neither is affordable as originally configured given the budget outlook in both countries.

Instead of giving up, the TRUTHS and CLARREO teams continue to study alternatives that would maintain some of the most important mission objectives at a substantially reduced cost. The British team is developing a concept called TRUTHS-Lite, a mission that would collect a narrower set of measurements over a shorter time period than the original. NASA scientists, meanwhile, are studying the feasibility of placing CLARREO’s main instruments aboard the international space station, a scheme that they believe would achieve more than 70 percent of the original mission objectives at less than half the cost. 

The TRUTHS and CLARREO redesign teams also are sharing their data, which makes sense given that the missions are intended to collect complementary measurement sets.

Despite their scientific relevance and importance — CLARREO was identified as a top priority in the U.S. National Research Council’s 2007 Earth science decadal survey — there is no guarantee that either mission will fly. Indeed, it’s probably fair to say the odds are less than 50-50 under current circumstances. But thanks to dedication, perseverance and some good old-fashioned optimism, both teams are likely to find themselves in position to take advantage should funding somehow materialize in the not-too distant future.