Also related to the SLS, the last of the 15 remaining RS-25D flight engines, formerly known as the Space Shuttle Main Engine (SSME), has been delivered to storage at Stennis. The plan is to use up the existing RS-25D engines on the expendable core stage of the new SLS before switching over to new-build, cheaper RS-25E engines designed to be expendable. The RS-25D has a number of features required in their role as reusable engines on the space shuttle which just aren’t necessary for an expendable engine. But the existing engines still have life left, so they’ll go out in a blaze of glory on one last mission on the SLS.

In more immediate news, the SpaceX COTS 2+ Mission, aka Falcon 9 Flight 3, which has been rescheduled a few times is now set to launch this morning, Saturday, May 19, at 04:55ET. This will be the first launch of a commercial spacecraft, the Dragon capsule, to the International Space Station. A truly historic event – and they have a live webcast on YouTube! It is set to start at 04:15ET – you can join now, there is a timer counting down to the start of the webcast:

You can also watch on NASA TV:

Live video for mobile from Ustream

And for something different, the recent Lyrid meteor shower as filmed from the ISS: