In a year when two International Space Station resupply ships have either blown up or careened out of control, there's no such thing as a routine resupply trip. And this week's cargo launch just got a lot more complicated: A rail-riding cart on the ISS jammed, and two astronauts are going on an emergency spacewalk to fix it before the Russian cargo ship docks.
The rail-riding cart, also known as the Mobile Transporter, is used to move around equipment like the ISS's robotic arms. The moving cart helps balance out ISS's weight on different sections, which is especially important when cargo ships are docking or undocking. And the robotic arm rides on the rail to grab and stabilize docking spacecraft. You can see where this is heading.
In a very unfortunate bit of timing, an ISS cargo ship is taking off early Monday morning. It'll arrive two days later. That gives ISS astronauts a day or two to get it fixed before the ship arrives. Right now, astronauts Scott Kelly and Tim Kopra are expected to go on a spacewalk to fix the cart on Monday morning.
You can watch both the launch and the spacewalk above. The livestream of the launch begins at 3:30 am ET and the spacewalk at 8:10 am ET.
