Science How the Space Shuttle Killed an American Halley’s Comet Mission

[MaverickSawyer]

I never heard much about STS pushing other programs out of the way during development, but the grounding after Challenger hurt it more than the accident did itself. NASA promised too high, delivered a bit too low, & the resulting gap killed the shuttles reputation.

That's where the origin of the EELV contracts came from. After they rapidly proved that the Titan IV was capable of taking up the slack, they focused on next-gen replacements.

I take it you feel that the USAF removing itself from the bozone layer was bad for NASA?

Not so much bad for NASA, as good for the Air Force. Also good for the unmanned spaceflight community, as this has created highly capable and flexible launchers that can loft payloads beyond what the shuttle was able to do.

 

[BruceJohnJennerLawso]

It hit squarely in the center of the leading edge RCC panels, and blew a hole clean through a whole panel (or so they believe: we'll never know what ACTUALLY got hit ), not blowing away a panel or hitting the gap between two panels.

What exactly is the difference between RCC & regular heat shield tiles?

 

[MaverickSawyer]

RCC (Reinforced Carbon-Carbon) was used on leading edges and on the hottest sections. It's also the most fragile material used on the shuttle TPS. Regular tiles are not rated for temperatures as high as those found on the leading edge, nose, rudder, etc.

 

[BruceJohnJennerLawso]

RCC (Reinforced Carbon-Carbon) was used on leading edges and on the hottest sections. It's also the most fragile material used on the shuttle TPS. Regular tiles are not rated for temperatures as high as those found on the leading edge, nose, rudder, etc.

I see. I dont really follow how that makes as big of a difference though, given that its still part of the heatshield as a whole. My guess would be that strikes strong enough to remove a regular heat tile would still cause significant damage to a RCC anyways, so a damaging impact on one was only a matter of time.

Is RCC similar to carbon nanotubes?

 

[garyw]

I see. I dont really follow how that makes as big of a difference though, given that its still part of the heatshield as a whole. My guess would be that strikes strong enough to remove a regular heat tile would still cause significant damage to a RCC anyways, so a damaging impact on one was only a matter of time.

It is but it's on the leading edge of the wing. A much more different material than the LI-900 silica tiles. The shuttle can and has survived with several tiles missing. It could never survive in a hole in the RCC.

This is a good example:

Sillica tile damage, quite a deep ding but the rest of the tile is intact and the heat flux never got into the gap due to how the heat laminar and turbulent flows work around the vehicle during entry.

Is RCC similar to carbon nanotubes?

No.

 

[Hlynkacg]

Taking it slowly would have avoided many issues that were seen in the early days of flight and allowed NASA to build up an anomaly database. Towards the end of the program most of the issues that were seen had a history which allowed the controllers much greater insight into the actual root cause of the problem and plan for either on orbit fixes or post landing fixes.

Again, sorry but I don't buy it.

A recurring theme in both the Challenger and Columbia incident reports was that NASA was aware of the anomalies but simply didn't care. The size of the database is therefore irrelevant to the discussion.

The Shuttle's primary mission was to build a space station. It just didn't get around to doing that until rather late into its life. There is no vehicle that comes even remotely close to being as well suited for the purpose.

No, it's primary mission was to service orbital tugs and propellant depots. The mission was changed to station building because NASA needed a project to justify spending billions on their new toy after their more ambitious plans fell through.

 

[Andy44]

I take it you feel that the USAF removing itself from the bozone layer was bad for NASA?

As someone mentioned, it was good for the Air Force, since they now had control over launching their own payloads and launch vehicle budget, allowing them to focus on what they needed to perform their mission without having to put on the dog and pony show for congress that NASA has to do with their highly visible manned program.

But it was bad for NASA, definitely. It removed a huge customer from NASA's launch manifests, and eliminated a key mission from STS, and amounted to a no-confidence vote from the Department of Defense.

It also resulted in the shutdown of the Vandenberg shuttle launch facility, which was only months away from launching the first-ever manned polar orbit missions. While this would've been used mainly for Air Force missions, it would've had NASA logos all over it and would've been a big step in the STS program.

The fact that billions of dollars were spent on it and it was essentially ready to go when the USAF killed it and cut their losses shows how badly the USAF wanted to get away from relying on NASA/STS.

 

[BruceJohnJennerLawso]

As someone mentioned, it was good for the Air Force, since they now had control over launching their own payloads and launch vehicle budget, allowing them to focus on what they needed to perform their mission without having to put on the dog and pony show for congress that NASA has to do with their highly visible manned program.

But it was bad for NASA, definitely. It removed a huge customer from NASA's launch manifests, and eliminated a key mission from STS, and amounted to a no-confidence vote from the Department of Defense.

It also resulted in the shutdown of the Vandenberg shuttle launch facility, which was only months away from launching the first-ever manned polar orbit missions. While this would've been used mainly for Air Force missions, it would've had NASA logos all over it and would've been a big step in the STS program.

The fact that billions of dollars were spent on it and it was essentially ready to go when the USAF killed it and cut their losses shows how badly the USAF wanted to get away from relying on NASA/STS.

Interesting. But, in the long run, why was it such a tragedy losing Vandenberg? It was only a launch facility, and it seems pointless to shoulder the cost of maintaining two launch sites.

 

[Andy44]

Interesting. But, in the long run, why was it such a tragedy losing Vandenberg? It was only a launch facility, and it seems pointless to shoulder the cost of maintaining two launch sites.

Prestige and publicity, and a bigger variety of launch azimuths. Some non-military missions would've benefited from that. As for the cost, the Pentagon probably would have covered much of that.

 

[Urwumpe]

Interesting. But, in the long run, why was it such a tragedy losing Vandenberg? It was only a launch facility, and it seems pointless to shoulder the cost of maintaining two launch sites.

You can't launch into polar orbits from KSC. The SRTM mission for example was nearly in the highest inclination that you can reach from KSC without launching over land and thus violate safety rules. The minimum permitted azimuth for KSC is AFAIR 20°, the maximum is 130°. Flying more south than 130° would result in passing over Cuba and cause an international accident.

It was a real tragedy - because of that, the SRTM only mapped +/- 55° of Earth. For full coverage, a polar orbit would have been needed. Also NASA worked on some polar weather satellites that should have been deployed by the Shuttle.

 

[garyw]

Over the years several articles have emerged about how Vandenburg would have been a poor launch site for shuttle. http://www.nytimes.com/1986/06/17/science/key-flaws-cited-at-vandenberg-shuttle-site.html

I've also read reports that talk about how the sound from the SRB's would bounce off the hills surrounding vandenburg and recombine to cause serious damage to the shuttle. I find that a little fair fetched but no doubt Vandenburg had issues.

 

[Urwumpe]

Over the years several articles have emerged about how Vandenburg would have been a poor launch site for shuttle. http://www.nytimes.com/1986/06/17/science/key-flaws-cited-at-vandenberg-shuttle-site.html

That criticism there is far far farsketched, but what do you expect from a Senator?

If hydrogen could gather in the exhaust ducts, the hydrogen source would have to be in it. Not above the entrance. Hydrogen rises pretty rapidly, as you can see during any Delta IV launch. Which launches often from the slightly modified Slick-6 BTW.

Also Vandenberg has no worse climate than KSC.

I've also read reports that talk about how the sound from the SRB's would bounce off the hills surrounding vandenburg and recombine to cause serious damage to the shuttle. I find that a little fair fetched but no doubt Vandenburg had issues.

Since the slightly louder Titan IV had been able to launch there without destroying the payload by excessive noise, I doubt it.

And which launch site has no issues? KSC had fireproof bricks flying away during launch, fauna nesting in the Shuttle and the occasional hurricane. Hail had badly damaged one Shuttle there.

A space launch complex is way more complicated than the bottle that you use for firing firework rockets - you can be sure that the pad rats are constantly busy.

 

[Cras]

No, it's primary mission was to service orbital tugs and propellant depots. The mission was changed to station building because NASA needed a project to justify spending billions on their new toy after their more ambitious plans fell through.

Nope. The Shuttle was designed to be the means to build a space station. The original proposal to NASA was to have the station, the shuttle, and the effort to go to Mars. Nixon cut the whole thing back to just the Shuttle, and for the first whatever years, we had a Shuttle but nowhere for it to go, so they improvised and came up with the commercial payloads, the Spacelab, and all that jazz, all still promoting it with the allure and science fiction feel of a re-usable space plane.

The mission was never changed to a space station. It just took a long time to finally get the support needed to realise that mission.

 

[worir1]

Technology always moves forwards never back...

 

[Ghostrider]

Technology always moves forwards never back...

I wish it were true. Science may always move forward but technology is, in the end, strongly conditioned by economics and market trends. If it doesn't make money, it's pushed to the side and forgotten.

 

[Hlynkacg]

Nope. The Shuttle was designed to be the means to build a space station. The original proposal to NASA was to have the station, the shuttle, and the effort to go to Mars. Nixon cut the whole thing back to just the Shuttle, and for the first whatever years, we had a Shuttle but nowhere for it to go, so they improvised and came up with the commercial payloads, the Spacelab, and all that jazz, all still promoting it with the allure and science fiction feel of a re-usable space plane.

The mission was never changed to a space station. It just took a long time to finally get the support needed to realise that mission.

I suggest you read both the 1968 Integrated Manned Program Plan in which the shuttle was initially proposed, and "The Space Shuttle Decision" by T.A. Heppenheimer.

Station building was a secondary mission that was added after the Air Force convinced NASA to increase the planned payload volume/mass to be capable of carrying the Military surveillance satellites of the day.

It did not become the primary mission until late in the development process when it became clear that the budget for the Tugs and orbital facilities would not be forthcoming. Unfortunately, by that time many of the design compromises that made the shuttle an inefficient crew/cargo carrier had already been made and NASA was essentially faced with matching a square peg to a round hole.

 

[garyw]

Technology always moves forwards never back...

Which is why we now only have subsonic commercial airlines whereas 10 years ago we had concorde.

Station building was a secondary mission that was added after the Air Force convinced NASA to increase the planned payload volume/mass to be capable of carrying the Military surveillance satellites of the day.

I have to admit that I thought that the shuttle was built with space stations in mind (dual-keel space station and all that). I thought the idea was that the station would be the hub of everything. GSO tugs for refuel and repair would be sent out from the station, shuttle would go there, etc.

I know that the Air Force added the large cross range component as they wanted to steal satellites in a single orbit.

 

[Urwumpe]

Which is why we now only have subsonic commercial airlines whereas 10 years ago we had concorde.

Or why SpaceX uses capsules and Gas generator cycle engines, while we had spaceplanes and staged combustion engines once only 2 years ago.

I have to admit that I thought that the shuttle was built with space stations in mind (dual-keel space station and all that). I thought the idea was that the station would be the hub of everything. GSO tugs for refuel and repair would be sent out from the station, shuttle would go there, etc.

That came later, when Space Station Freedom was developed. Initially, it was actually planned to use the Shuttle to reboost Skylab and keep Skylab running for some more years, before a successor is developed. And the space tugs had been the primary tool for many missions, including reusable ones. The payload bay was designed largely to be an assembly and maintainance platform for satellites and space tugs. That it was also good for station building was a nice side effect.

I know that the Air Force added the large cross range component as they wanted to steal satellites in a single orbit.

Not steal - deploy satellites or simply use camera payloads from the payload bay.

Less than one orbit would have been quite an achievement for rendezvous, especially with a target that is not your own. I needed 9 hours lately to rendezvous with a non-cooperative ISS in Orbiter and felt I was fast.

You need quite a long time after launch to configure the Space Shuttle for orbital operations.

BUT: If you never plan to go orbital, it is no problem to open the payload bay doors and still have about 30 minutes left for observations, before you need to close them again and rotate the Shuttle for the approaching EI.

 

[garyw]

That came later, when Space Station Freedom was developed.

Not according to 'the space shuttle handbook' - 1979 which is fun to read as it's so damn optimistic about what the shuttle could do. In that (chapter 9) they talk about power from space, space stations, including an early version of the dual keel design and more.

Initially, it was actually planned to use the Shuttle to reboost Skylab and keep Skylab running for some more years,

Well yes, Skylab gave shuttle a destination. The plan was a reboost on STS-6 then it was on STS-4 and finally on STS-2 but it deorbited before shuttle could fly.

Not steal - deploy satellites or simply use camera payloads from the payload bay.

I thought steal was in there too? Certainly shoot down is.

Less than one orbit would have been quite an achievement for rendezvous, especially with a target that is not your own

According to this 1979 book they wanted two week turn-around times and 60 shuttle launches a year.

BUT: If you never plan to go orbital, it is no problem to open the payload bay doors and still have about 30 minutes left for observations, before you need to close them again and rotate the Shuttle for the approaching EI.

and pray that the bay doors close again afterward.

 

[Urwumpe]

According to this 1979 book they wanted two week turn-around times and 60 shuttle launches a year.

That wasn't actually too fantastic. You could really launch about once per week, if you would have had less time required for TPS and engine servicing.