NASA, SpaceX launch ISS's last new solar arrays today

NASA and SpaceX are set to launch a Cargo Dragon capsule Tuesday morning. It's carrying 6,300 pounds of supplies to the International Space Station. Tucked inside is something bigger than groceries: the station's last set of roll-out solar arrays. Once astronauts install them, the ISS finishes a power upgrade that's been years in the making.

The station has needed this for a while. More solar power means more electricity for the science experiments and life-support gear the crew runs day to day. It's also the final piece of a power upgrade NASA has been building toward for years.

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Will the astronauts' spacewalks to install these arrays go smoothly? Any spacewalk adds real risk, and this one finishes a years-long project. If it goes well, the ISS finally runs on full power for whatever time it has left before retirement.