How hard would it be to fly a Space Shuttle again?

Question

Since in the wake of the failure of Soyuz MS-10, "humanity is effectively trapped on Earth" (this of course ignores Chinese launchers), one might try to fly one of the remaining Space Shuttle orbiters again. How hard would it be to get them into space and safely back again (assuming they don't have to be man-rated against current criteria)?

I see some problems:

1. The orbiters are all in some kind of museum, but important parts (e.g. computers, engines) may have been removed or modified for display, so they might need replacement. And the orbiters probably need at least a C check.
2. One would need a new external tank, since I don't think one is in storage. I somehow doubt that tools, etc. needed were safely stored away.
3. The boosters might be the easiest part since SLS uses improved versions.
4. The infrastructure at Cape Canaveral (Orbiter Processing Facility, Vehicle Assembly Building, Mobile Launcher Platform, Launch Pads, ...) would need to be adapted.
5. The Shuttle Carriers have been retired; maybe N905NA could fly again.
6. Astronauts and ground crews would need to be trained.

So how many years would it be before e.g. Atlantis would fly again?

Answer 1

In practical terms, it would be impossible.

The Orbiters were designed in the late 1970s and built with the technology of that time. Late in the program there were many logistics nightmares as parts became impossible to find as manufacturers went away or stopped unprofitable lines. In essence, a near-total redesign would be required.

Former flight director and Space Shuttle Program head Wayne Hale has an eloquent article about it here. Note that this was written in 2008 while shuttles were still flying but after the decision to terminate the program had been made.

To take one little example: if we started today to build another external tank at MAF, there are probably enough parts on the shelf. But very shortly we would exhaust supplies of some parts. Maybe on the second tank — which we need to start in 3 months or so — would have to get a new supply of specialty parts. Sometimes the old vendor is still there and could be persuaded to make more of the old parts. But in many cases, a new vendor would have to be found. Since the production run would be small, a premium price would have to be paid; and a certification effort requiring 6 to 12 months would start. Initial production likely would have a number of rejects as the workers learn the process. Hmm. In probably 15 to 18 months would would have the parts to build that second tank — only a year or so later than we needed them. So a new gap would form. Not between shuttle and orion but between shuttle and shuttle.

The training simulators are gone, the shuttle Mission Control is gone, the operations contractor is out of business, the workforce is dispersed. Consummatum est.

Answer 2

The Space Shuttle (or any complicated system for that matter) is not just composed of the hardware itself. It is a system composed of all the infrastructure needed to get it to work. The hardware needed to manufacture and quality check the specific components, the hundreds or thousands of scientists, engineers, technicians and mechanics with specific domain knowledge who are now retired or in different jobs. Think of the shuttle itself as the capstone of a gigantic pyramid of social, scientific and commercial infrastructure.

The space shuttle is composed of thousands of subsystems that all (or almost all) have to work just right for the shuttle to even lift off. Without the army of people with intimate knowledge of the subsystems they are responsible for, the supply chain for the manufacture of the many and varied specialty parts, and the huge flow of cash to maintain the existence of both even during periods of no activity, you're not going to get a space shuttle to orbit.

Answer 3

The biggest problem with trying to launch a shuttle today is that all of their engines (both used and spare) have been cannibalised for the SLS program and are currently undergoing upgrades and testing with relation to that.

Whether or not this was a sensible thing to do (it wasn't), that alone means that there is no way a shuttle could launch today. There simply aren't any engines available for them. And in case you thought it would be easy to just build some more, they're doing that anyway; the production line for these engines is in the process of being restarted... it will take another three years before it completes its first engine.

The next show stopper is that the shuttle launch pads have been taken over by other launch vehicles, and have been adapted for their use. SpaceX has spent the last several years ripping out the Shuttle-specific features at LC39A, and have recently installed their own crew access arm for their Crew Dragon spacecraft. The other shuttle pad LC39B has been similarly rendered unsuitable for a shuttle launch today.

Finally (well, I say that, but...) the shuttles themselves are now museum pieces and are no longer in a fit state to fly. They would require significant maintenance, to the point of effectively re-building them, in order to make them airworthy, let alone spaceworthy. If you started this today with a skilled workforce, you could maybe get one of them ready inside of a year. Maybe. But even if you did want to do this work, there is likely nobody around capable of doing it; the skilled personnel capable of working on the shuttle have long since moved on to different roles or retired.

Answer 4

Apart from all the missing spare parts and infrastructure: You couldn't even fly a 10 year old airplane unless you "take the entire airplane apart for inspection and overhaul". After 40 years this does not concern single parts which could be exchanged; this concerns the whole craft.

Contacts oxidize, plastic becomes brittle, lubricants gel, condensation collects, capacitors age.

But a spacecraft is to an aircraft what a formula 1 race car is to a VW Beetle. It's a radical optimization leaving very little fault tolerance. Many failures are mission critical. Gravity and atmosphere and structural stress and temperature and all the other odds are, without exception, stacked against you, and will kill you if any part fails.