I waited nearly a year and a half for the first JPL mission to launch after I started.  For the second, it will be just over two weeks.

Next Tuesday, GRACE-FO (or GRACE-Follow On) will launch from Vandenberg Air Force Base to begin a multi-year study to track water movement, soil moisture, ice sheets & glaciers, sea levels, and dryer earth.  It’s a shared project between JPL and the German Research Center for Geosciences.  While mostly built at facilities in Germany, much of the project management and testing has been on our side.

Like other projects I talked about before here, I’ve had some passing involvement in the project.  In fact, similar to the InSight mission launched a few weeks ago, I was at the final assembly and test facilities used for GRACE-FO at VAFB … so close to the mission, that I had to race around it as it was transferring between buildings so that my testing wouldn’t delay it’s arrival.

Short for Gravity Recovery & Climate Experiment Follow-On, the dual satellite design flying 220km apart measures variations in gravity between the two satellites.  This data, tied with accurate GPS measurement, means that the specific gravity on the Earth’s surface can be mapped so accurately that wide sweeps of moisture levels can be detected.  Those maps then are redone regularly so changes can be monitored.

Or the less scientific description:  Water Moves Around the Earth All the Time, this is telling us where it goes.

The “Follow-On” in the name should tell you something too.  This isn’t the first GRACE.  This is actually, the continuation on existing technology.  The first GRACE was launched in 2002, and continued to collect data up to October 2017 when the batteries finally hit their life.  That means if all goes well with GRACE-FO’s launch, it will go for another 15 years at least.

The launch has been an issue.  Originally scheduled for March, the date has slipped a number of times … but it wasn’t our fault.  GRACE-FO launches on a SpaceX Falcoln 9 with five commercial satellites called Iridium Next (which will be a big deal some day for internet, but not the point).  Those other satellites had some issues to work though, pushing back the overall launch plan.  Then of course, InSight took precedence.  Right now, there is a good window to go up on Tuesday May 22nd at about 12:45pm local time.  I won’t be up at VAFB for the launch … I have to work; but the fact that it will launch while I am at work has me curious to see what they do.

Still, it’s another check in the box, another mission, and another opportunity for us to learn more about the world we live in.

And another cool launch.