That was the design specification. But then, they had other design specifications, like 65,000 lbs to LEO, and $22M per flight, and 55 flights per year…

Really? Maybe for each unit calculation, but the mass in electronics in modern vehicles is unlikely to be significantly less than in prior vehicles. We always seem able to fill every available space with electronic gizmos. Look at the recent Airbus fiascos. What is the total mass of electronics in a B-2 versus a B-52? If anything, we should probably be limited the mass of Orion so that future generations have limited space to put more electronic crap to go wrong. . . .

— Donald

If we could accurately predict which aerospace vehicles would have the longevity of the B-52 or manned Soyuz, I’d agree with you.

The problem is that there’s only a handful or two such vehicles out of the hundreds to thousands of vehicles developed since the advent of powered flight. Against those odds, it’s arguably foolish hubris to presume that a system we’re designing today will be used a few decades from now, especially if that presumption drives the system’s requirements, design choices, and costs.

I’d also note that the longevity of the B-52 and Soyuz are due more to accidents of history than any careful planning.

“few if any of the Shuttle’s problems seem directly related to the airframe’s age”

You’re absolutely right that the Shuttle airframes have lots of flights left in them (100 each total, IIRC). But the airframes are not the parts of the system that drive Shuttle’s operational, maintenance, and upgrade costs. Nor are they the parts of the system that make it so dangerous to fly.

“Why do we insist on continuing to re-invent the wheel?”

There’s big differences between:

1) needlessly reinventing a recently built and working wheel (Ares I and EELV),

2) spending lots of very limited funds trying to make a wheel last for decades to fulfill a future mission (Ares I/V),

3) and replacing a dangerously and expensively designed wheel (Shuttle).

I’d agree with you that 1 is not justified. I’d argue that 2 is also not justified. But 3 is obviously justified.

“For that job, why do we not design for the ages, leaving room for the “astroionics” to be changed out as new equipment becomes available.”

Upgrades to computer-intensive GN&C systems will only shrink in mass and volume over time.

FWIW…

Is that so? We got multiple crews to the moon with no deaths or serious injuries in space. We achieved far better and more comprehensive science than has been even attempted at any other extraterrestrial location, before or since. We gained a great deal of practical experience and sustained an immensely steep learning curve.

Sounds like a pretty successful version to me. . . .

— Donald

The previous triangular and square versions didn’t work all that well.

Maybe it shouldn’t be another discussion. Let us recall that, while the United States wasted (as it turned out) bazzilians on the Shuttle, the Space Station is being supported by one of the earliest human spacecraft and launch vehicles ever designed. Meanwhile, B-52s even older than I am seem to be doing a fine job, and few if any of the Shuttle’s problems seem directly related to the airframe’s age (although I’ll be interested to hear the thoughts of others on that). Why do we insist on continuing to re-invent the wheel? We have decades of experience building capsules capable of functioning in cis-Lunar space: if we can’t do it now, when will we be able to do it better? For that job, why do we not design for the ages, leaving room for the “astroionics” to be changed out as new equipment becomes available.

In that light, vze3gz45 makes some interesting points. . . .

— Donald

For lunar transport, the apples-to-apples comparison would be Apollo (obviously). And if the numbers above are accurate, Orion’s volume per crewmember is again bigger than Apollo’s by a factor of a little over 50 percent.

And for LEO transport, I’d just reiterate Mr. Fansome’s statement.

“We should not launch people into orbit in cans anymore like the Apollo command/service module. Astronauts should have a decent amount of room while launching and while waiting on orbit to transfer to a space station or Mars spacecraft.”

When looked at in isolation, it’s a value judgement that can go either way.

But in terms of the system, every extra cubic foot of volume carries with it tens to hundreds of additional pounds in terms of the extra structural mass needed to enclose it and the extra propellant needed to launch it. In that context, which is the one the engineers have to deal with, and especially on systems with thin margins like launch vehicles, extra crewmember volume becomes a “nice-to-have”, not a “must-have”.

It’s also strange (at least to me) that we’re designing in extra volume for taxpayer-paid, risk-taking, right-stuff astronauts while the private astronauts paying their own way on Dragon and CTV will make do with less. It’s kind of like mandating first class airfare for government employees (which of course the federal government does not do) when most folks are fine flying coach. Not a good use of taxpayer dollars, at least in my opinion.

“Who knows. Orion may have to be used as a rescue craft to rescue astronauts from a damaged Mars space ship someday.”

If it’s a legitimate requirement, it should be documented as such. Unspoken and unwritten requirements assumptions are the bane of complex development projects (in human space flight or elsewhere).

FWIW…

I totally disagree. The days of spam in the can ended with the space shuttle. We should not launch people into orbit in cans anymore like the Apollo command/service module. Astronauts should have a decent amount of room while launching and while waiting on orbit to transfer to a space station or Mars spacecraft. The size of Orion is good. Who knows. Orion may have to be used as a rescue craft to rescue astronauts from a damaged Mars space ship someday.

vze3gz45

– Al