A used SpaceX Falcon 9 rocket will do its best impression of an Uber on Tuesday when it sends several satellites to orbit for both NASA and telecom company Iridium.

The rare ride-sharing arrangement will carry five of Iridium's next-generation satellites and the twin spacecraft that make up the GRACE Follow-On (FO) mission for NASA and the German Research Centre for Geosciences (GFZ). 

The original GRACE (Gravity Recovery and Climate Experiment) mission observed the movement of water around the planet. GRACE-FO will continue that work by tracking movement of water and other types of mass on Earth, gathering data that can monitor changes in ice sheets, glaciers, underground water stores, lakes, rivers and oceans. The two Earth-watching satellites will also test new technology that uses laser to measure the distance between them rather than microwaves.

After the Falcon 9 liftoff from Vandenberg Air Force Base's Space Launch Complex in California -- currently set for 12:47 p.m. PT -- the GRACE-FO satellite will be deployed about 11 minutes later. 

The upper stage of the Falcon 9 will then spend about 45 minutes cruising before restarting to fly to a different orbit where five new Iridium satellites will be deployed. The company is in the midst of a multiyear process to replace its aging satellite constellation with dozens of new satellites. 

SpaceX doesn't plan to land and recover the first stage of the Falcon 9. This rocket was previously used to boost the top secret Zuma spacecraft to orbit, which was then reported to have suffered a payload adapter malfunction. The spacecraft failed to separate from the rocket upper stage and reentered the atmosphere, where it burned up. Later reports cleared SpaceX of any blame for the $3.5 billion botching.

Elon Musk's company may attempt to recover the nose cone that protects the payload during ascent using a boat in the Pacific Ocean equipped with a giant net. 

You can watch the live webcast of the mission in the embedded video above. The webcast should begin around 12:30 p.m. PT.

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