>==
> Most people have no idea why the Shuttle is more expensive to
> fly than was originally predicted. It is not because it is reusable, ==

True.

>== it’s primarily because it was built without any prototypes that
> could actually fly in space. Consequently there was no accurate
> way to predict cost or risk and many critical design decisions
> were made that, in retrospect, were incorrect. ==

No and yes. After flying the first couple shuttle flights they learned a lot of things didn’t work as well as expected (tiles, some internal systems, etc), but those could have been refited. The external tank adn SRB design was just a rush job tossed in as a quick (2-3 day) driven by a gov edict.

The big problems were NASA waas pushed to keep costs up, as well as keep up and maintained centers designed for programs far larger then Apollo or Shuttle. These were political givens that drove NASA.

>== The argument here is about what it did, versus what it was
> intended to do. ==

I thought we were talking about why Griffen didn’t like about it, adn wanted different in the next system?

>== And I actually don’t recall any specific plans to use the Shuttle
> to raise Moon or Mars ships.===

Yeah as late as the 90’s they were doing studies and proposals for a return to the mon with craft that could be deployed in Earth orbit fro shuttle, go to the moon, return to LEo, then be picked up adn returned to Earth with shuttle.

>== It lifted large pieces along with people, which may have been
> a justifiable strategy then, but is assuredly not now. ==

Why?

>== Far larger and more complex than an HLV could do? Not quite. ==

Defiantly. They budgeted about 20 flights to build the ISS – and that’s 500 tons, with a lot of on orbit assembly, allowing a more space optimized design. There are downsides to the modularity — but for big scale projects or assemblies, its pretty much the only way to do it.

>>>“”Maybe the time has come to see some evolution in the skill
>>> sets that are available to make space exploration happen properly.””

>> “By eliminating everyone (or nearly everyone) with any maned
>> space exploration experence?”

> Nope. Never said that. In no way is retirement of Shuttle eliminating
> nearly everyone with manned space flight experience. == As I said,
> you won’t end up with engineers and technicians out by the dumpster, =

And where are they going to go with no jobs for anyone with their skill sets?

#1 – as soon as those contracts end they are all laid off. Few folks at the centers work for NASA.

#2 – then NASA Brings in new contract teams who hire folks with the diffent skills.

Now given they are laying off folks who know how to fly and operate space craft, and those who know how to develop and build space craft. And they have very little need for anyone with those skills at NASA, and NASA was a major fraction of the market, and NASA not really going to replace them with new engineering needs in other projects, they are forced out of the industry.

Not really new – US areospace and manufacturing isn’t doing real well.

Yes I knew engineers can shift back and forth between wildly different jobs – I made a career out of it – but you still lose skills and knowledge when you lose experenced folks.

Authorising the Shuttle on the other hand…

That might be because it was canceled by Johnson, many years earlier than that. Nixon was an awful president, in many ways, but cancelling Apollo was not one of his sins.

Astonishingly, almost no one I know in the space program knows why Apollo was canceled (by Nixon) in 1974. Sending people even to the Moon with big expendable rockets was, an is, much too expensive to be practical. A few remember that Shuttle was developed for a very simple reason. Most of the astronomical cost of human spaceflight is in building a new launch vehicle and spacecraft for each mission. The fuel for the Shuttle costss almost nothing; hydrogen is 98 cents a gallon at LC-39, LOX is 60 cents a gallon.

Most people have no idea why the Shuttle is more expensive to fly than was originally predicted. It is not because it is reusable, it’s primarily because it was built without any prototypes that could actually fly in space. Consequently there was no accurate way to predict cost or risk and many critical design decisions were made that, in retrospect, were incorrect. Obviously constructing a new external fuel tank and completely rebuilding the SRBs is a large part of it, but maintaining the VAB, MLPs, crawlers and ships is also expensive.

That’s why NASA initiated the Reusable Launch Vehicle program, to test design concepts and critical systems for a new generation of shuttles that would be both safe and practical. The X-33, X-34, X-37 and DC-X were part of that program. Unfortunately Bush and Griffin canceled all the technology demonstrators in favor of Apollo on Steroids.

C’mon. The argument here is about what it did, versus what it was intended to do. And I actually don’t recall any specific plans to use the Shuttle to raise Moon or Mars ships. It lifted large pieces along with people, which may have been a justifiable strategy then, but is assuredly not now. Far larger and more complex than an HLV could do? Not quite. These days, payload to LEO of a Shuttle is of order 25mT. That mass is easily accommodated by a Delta IV-H, which has a comparable shroud diameter. Yes, payload length can’t be quite as long as in a Shuttle, but that’s rarely an issue.

“”Maybe the time has come to see some evolution in the skill sets that are available to make space exploration happen properly.””

“By eliminating everyone (or nearly everyone) with any maned space exploration experence?”

Nope. Never said that. In no way is retirement of Shuttle eliminating nearly everyone with manned space flight experience. It may well be eliminating their job description, especially if that job description happens to be first assistant screw tightener on SSMEs. As I said, you won’t end up with engineers and technicians out by the dumpster, but you will end up with a pile of job descriptions out there. For those people who are wedded to their job description instead of to their training, I do have pity for them.

I suppose there are some elderly Edsel engineers wandering around out there, still looking for work. But most just moved on.

> carbon nanotubes (CNTs) being developed for the tether have far
> better strength to weight ratios than the best steel. ==

The nanotubes has stunning strength. But the cables made out of them don’t. You can’t make single nanotubes stretching from the ground to orbit, and more then nylon ropes are made out of nylon lines the full length. You briad or glue strands into the bigger ropes. That’s where nanotubes fall down. The nanotubes are extremely slippery, so there’s little friction between them and other materials – nor do adhesives stick to them.

Nano tubes are moving into commercial use – but they no longer talk about structural uses.

To make it worse, space elevators have such huge capital costs, and such low carrying capacity – it seems unlikely they could lift material to orbit at costs competitive with current rockets – much les future ones.

>> “NASA will retain its head count – its just the skill set of those
>> on salary or subcontracted will be different. New company’s
>> will bid for the new contracts to staff the centers, with all
>> new people with new skillsets”

> So, um, this is not about preserving jobs. It’s about preserving
> YOUR job.==

I haven’t worked there for years.

>== Maybe the time has come to see some evolution in the skill
> sets that are available to make space exploration happen properly.==

By eliminating everyone (or nearly everyone) with any maned space exploration experence?

>>=
>> “He believed Shuttle made space to routinely accessible,
>> which wasn’t in NASA political interest.”

> == No way. Shuttle didn’t make space “routinely accessible”.
> Not by a long shot. In fact, it made it very expensive. Mike
> knew that, and he knew he needed to pull the plug.

It wasn’t routine and low cost by our standards, but it was far to routine and low cost for Mike. So Constellation would cost several times as much per launch ($7B-$9B by various GAO estimates), and fly far fewer times, but they would be big spectacular Apollo style launches and recoveries.

>== Shuttle was certainly not built to “get us to Moon and Mars”, ==

Oh contra – the concept was shuttles could lift and assemble massive stations (bigger then ISS), and deep space ships. Shuttle was to be the space truck that lifted the peaces to assemble in orbit, craft and platforms far larger and more complex then a HLV could do.