Q&A with Tim Ellis, CEO and co-founder of Relativity Space (members only)

A pair of European-built, NASA-backed research satellites set for launch Tuesday from California will extend 15 years of global gravity field measurements collected by the GRACE mission before it ended last year, supplying scientists with data to help track the melting of Earth’s ice sheets and chart the impacts of floods and droughts.

Northrop Grumman’s Pegasus XL rocket will take about 11 minutes to place NASA’s Ionospheric Connection Explorer, or ICON, satellite into a roughly 357-mile-high (575-kilometer) orbit after an airborne launch off Florida’s east coast.

Some time in the next few days, a California-based company that has quietly toiled to develop a new light-class satellite launcher since 2016 will attempt to send three CubeSats into orbit from Kodiak Island, Alaska, on the first of two missions scheduled before the end of March to win up to $12 million in prize money from the U.S. military.