I don't think those are "large" assumptions, they're pretty standard things that can go wrong with every flight. Not that useful to have to enumerate them every time anyone talks about spaceflight.
- mission commander not being changed
- rocket not blowing up on the pad
- rocket reaching correct orbit
- mission not being completed, for instance docking issues
- everything that could possibly go wrong on the return flight
Really, the ease with which everybody seems to assume that this will go off without a hitch is impressive, this is not exactly walking to the corner store to pick up a small parcel.
Friend: I'm going to grab more drinks from the store
You: There are several very large assumptions implicit in that sentence
Friend: ?
You: Your car can break down, you can get in an accident on the way there, the store can be robbed and you can get shot, you may get a call about your parents dying on the way, a meteor may strike and kills us all...
Imagine if anytime anyone spoke about spaceflight, they saw fit to include a giant disclaimer of everything that could go wrong. We'd all just end up sounding like drug commercials.
* You could sprain your ankle and not make it
* The parcel might have been stolen by a robber
* The corner store might be on fire
* Feral dogs might chase you to the other side of town
"The shuttle replica accompanied an expected presentation of a U.S. flag that was flown on the first and last shuttle missions. The 8- by 12-inch flag, which was revealed by President Barack Obama during his call to the astronauts last week, will stay on board the station until the shuttle's successor arrives.
"This flag represents not just a symbol of our national pride and honor, but in this particular case, it represents a goal," Ferguson said. "This flag will be flown prominently here by the forward hatch of Node 2, to be returned to Earth once again by an astronaut that launches on a U.S. vehicle, hopefully in just a few years." [9 Weird Things That Flew On NASA's Shuttles]
Both the model and flag were hung near and on the hatch where 35 space shuttle crews have entered the station and where the STS-135 astronauts exited for a final time soon after presenting the mementos."
https://www.space.com/12335-shuttle-astronauts-flag-model-sp...