The livestream has begun for tonight's #NASA #Boeing #Starliner Crewed Test Flight, targeting 10:34 PM EDT.
#NASA and #Boeing have scrubbed tonight's #Starliner launch due to a problem with an oxygen relief valve on the second stage.
From #NASA: Now targeting no earlier than (NET) Friday May 10 for another #Boeing #Starliner Crewed Test Flight.
No time given in the blog post. For #ISS flights, they move up roughly 23 minutes each day due to orbital mechanics, so if last night was targeting 10:34 PM EDT, figure Friday will be around 9:00 PM EDT (a more civil hour).
Warning, boring orbital mechanics screed ...
#ISS orbits Earth at 51° to the equator so it can pass over both #KSC and Baikonur.
If you attend a night launch, you'll see ISS pass over KSC just before so the crew vehicle is on the same trajectory.
ISS orbits Earth once every 90 minutes, 18 times a day. But Earth is rotating too, so the upshot is that ISS passes over KSC about once a day minus 22-23 minutes.
You can see ISS pass over KSC in this video at the 5:20 mark.
You might think that Shuttle (in that video) or any other crewed vehicle is going to try to catch up to #ISS, but that's not quite how it works.
ISS-bound vehicles typically launch to an altitude slightly higher than the station's orbit, then begin a dance slowly falling back to Earth to intercept the ISS orbit. It's easier than trying to chase the station.
Orbital mechanics can be mind-bending.