Enormous amounts of valuable data have been collected from the rocket and spacecraft missions conducted by NASA and other federal agencies over the past 35 years, as well as from collaborations with groundbased experiments and international space missions. What do we now do with all these perishable data?Many of the NASA data sets have been archived in the National Space Science Data Center (NSSDC) at Goddard Space Flight Center in Greenbelt, Md. Most of the data sets from spacecraft operated by the National Oceanic and Atmospheric Administration are archived in the National Geophysical Data Center in Boulder, Colo., and other data sets are archived at various regional data centers. Yet there are undoubtedly many data sets that reside with the instrument's principal investigators or associate researchers at various universities, colleges, and aerospace laboratories—data that are not now included in the national archiving effort. Many of these data sets include highly reduced, value‐added data, which required significant resources to acquire and reduce.