End of the Space Shuttle - Overall verdict

[MrDakka]

NASA isn't actually thinking about a straight-up replacement for the Shuttle as much as a series of systems to replace the Shuttle's mission.

There's Dragon (with Soyuz as a stopgap) as the outsourced low-orbit passenger taxi, the Space Launch System medium/heavy lifter for cargo, the European ATV as a replacement for Progress and MPCV as a command module for long-range ships to be based upon.

These are mostly concepts right now (only the Dragon and ATV is in a useable state, though the Dragon still has a couple years to go and IIRC still hasn't got a docking mechanism?), but they do show NASA learned their lesson from the Shuttle.

You know, I was really sad when Constellation was cancelled, but it does look like we may yet see an entire new generation of manned spacecraft in our lifetimes, with exciting new prospects for manned spaceflight still there. We may see humans land on an asteroid, for example.

Speaking of Shuttle replacements, has anyone here heard of the Dream Chaser being built by Sierra Nevada Corporation. I ran across their booth at a career fair on campus, but I can't find too details.

[Skgoa]

Its one of a multitude of commercial designs still stuck in r&d that NASA has given a little bit of money to. If anything comes from it, it might ferry people to Station. Essentially the same thing as CRV, Hermes etc., though it seems to be more or less on track, with only two years between when the wanted to launch their prototype (2010) and when they will most probably launch it. (2012)

[MrDakka]

Figures. Hopefully some of these replacements might actually get in production.

Btw is it just me or does NASA seem to be taking a shotgun approach to the whole shuttle replacement

[PeZook]

Btw is it just me or does NASA seem to be taking a shotgun approach to the whole shuttle replacement

Why? The "one vehicle does it all" approach was...subooptimal, so they will try to introduce a slew of specialized vehicles instead.

[someone_else]

Although it's unclear if they actually need anything more than a reusable capsule for people and maybe a capsule for the engines.

That's the only two things you usually want to recover.

[PeZook]

Although it's unclear if they actually need anything more than a reusable capsule for people and maybe a capsule for the engines.

That's the only two things you usually want to recover.

Uhh...the Dragon is actually disposable. It's really America's Soyuz.

You also need a resupply spacecraft (SpaceX is actually trying to butt into that niche, too) specialized for cargo, and occasionally something heavier for those times where you really want oomph, like constructing another space station, hurling landers to the Moon, larger supply runs, etc.

Having recoverable orbital engines is kinda tricky though yeah it would be great if you could have an el cheapo space launch system that could use extremely efficient engines like the SSME.

[someone_else]

I was thinking conceptually. If you just have to bring back the crew and at most the engines, making a spaceplane is overkill no matter how small.

Although I thought Dragon was intended to be reusable. Maybe the cargo version isn't (that's the capsule which will go resupply the ISS in their plans) but the man-rated one should be. I read it should last for 10 reentries somewhere.

A fun concept would be the crew capsule that also houses the engines, and stays in the bottom of the rocket. Horriby unsafe and completely unescapable, but when it works you have both crew and engine in one capsule.

[PeZook]

I was thinking conceptually. If you just have to bring back the crew and at most the engines, making a spaceplane is overkill no matter how small.

Actually the spaceplane shape is kinda great for shielding the engines during re-entry. Doing the same with the headlight shape is way more tricky.

Although I thought Dragon was intended to be reusable. Maybe the cargo version isn't (that's the capsule which will go resupply the ISS in their plans) but the man-rated one should be. I read it should last for 10 reentries somewhere.

Oh, right. My bad - though it remains to be seen if they retain that capability ; In theory, the Vostok was reuseable, too - the capsules were disposed of out of safety concerns.

Dragon is still flight testing so the reuseability feature might be dumped, since its primary advantage was always supposed to be cost cost cost above all, so if refurbishing the capsule will be too costly or the risk associated with reuseability turn out to be too high, that's almost certainly the first thing to get axed. Especially since repeated stresses of a ballistic landing fuck up the very structure of the spacecraft, unlike a glided landing of the Shuttle.

A fun concept would be the crew capsule that also houses the engines, and stays in the bottom of the rocket. Horriby unsafe and completely unescapable, but when it works you have both crew and engine in one capsule.

It also suffers problems with staging. But you could do something similar to the Shuttle, except lose the orbiter and have the reentry vehicle do ballistic flight.

[Highlord Laan]

Atlantis has touched down safely. Welcome back to the crew. A toast to the shuttle and it crews, and a mighty fuck you to all the politics-playing flat earth shitbags that took the US out of the spaceflight business and now claim their victory. My you all fall into your gilded, fat-encrusted graves and die clutching you precious celeb news.

[Skylon]

Hail Columbia, Challenger, Discovery, Atlantis and Endeavour. For all their flaws, they kept us in the manned spaceflight business and provided a glimpse of a "Buck Rogers" future, even while showing that we are either not ready for that future, or it is not viable. And cheers to the shuttle crews and the people on the ground who built, serviced and controlled those vehicles, who hopefully can apply their expertise to a new generation of vehicles.

Let's hope the journey continues.

I watched the landing at the "Cradle of Aviation" museum here on Long Island over free coffee and donuts (and free entry). It was nice to then walk around a mostly empty museum aside from the 20-30 other people who woke up that early...especially being able to look at the Lunar Module they have, in relative silence, with nobody else around.

[PeZook]

I have missed the live transmission due to work, but even though I watched it afterwards, I felt a pang of pain upon hearing Chris Fergusson saying "After 30 years of history, Atlantis has come to a final stop"

Call me sentimental, irrational or hell even an idiot, but I loved the Shuttles, even with all their flaws.

"Although we got to take the ride," said Commander Chris Ferguson on behalf of his crew, " we sure hope that everybody who has ever worked on, or touched, or looked at, or envied or admired a space shuttle was able to take just a little part of the journey with us."

[Skgoa]

For all their flaws, they kept us in the manned spaceflight business and provided a glimpse of a "Buck Rogers" future, even while showing that we are either not ready for that future, or it is not viable.

It has been said often in the previous threads on space flight, but since this thread is called "overal verdict", I guess its as good a place as any to repeat it:
The Space Shuttle Program managed to design, build and operate a vehicle that had to fulfill a variety of requirements that had been handed down to NASA from the US government, on a budget that the US government set... while other parts of the US government tried to kill it every step of the way. Several of those requirements were really really stupid considering what the shuttle had been ment to be, but since this was going to be the only heavy lift launch vehicle for a while, the military insisted on them. NASA had to take the whole set of requirements or kiss their shuttle goodbye. And you know what... they actually pulled it of. They managed to build the shuttle on budget and provided relatively cheap and reliable access to space for the US and it's partners. The US government didn't want to fund alternatives or *gasp* a replacement, until there was a second accident and all of a sudden everyone just knew the Shuttle was to old, costly and dangerous to fly. Even though the orbiters had upgrades all the time. And after decades of having this great tool, people go "why does it have to cost so much? look at the other guys, they do just fine with still using Soyuz!"
Now, acknowledging fiscal realities in the current global recession is reasonable. Claiming that this is the natural state of things is something else entirely.

Let's hope the journey continues.

It does. The next generation of space vehicles is already being designed and build. For the first time since the early 70'ies exploration beyond earth orbit is once again the focus.

[Skylon]

It does. The next generation of space vehicles is already being designed and build. For the first time since the early 70'ies exploration beyond earth orbit is once again the focus.

I hope so. I'll have more optimism when the actual hardware starts to materialize. But I'm certainly not going to join the "It's the end of American space flight!" crowd.

[someone_else]

Actually the spaceplane shape is kinda great for shielding the engines during re-entry. Doing the same with the headlight shape is way more tricky.

Yeah, but you need those engines close to the bottom of the rocket. Which means your crew will be in a dangerous place if something screws up.

I think it's better for the engines to be in their own capsule, facing up while reentring. And inflatable reentry shields may be of some use in reducing mass and softening landing here.

Especially since repeated stresses of a ballistic landing fuck up the very structure of the spacecraft, unlike a glided landing of the Shuttle.

Ballistic reentry doesn't have to be horribly stressful. Any capsule bringing humans down does have to generate significant lift anyway to keep descent speed (and deceleration) compatible with safe landing (and human life). Apollo capsule managed to decelerate at 4 gees while the shuttle decelerated at 3 gees. It's not a huge gap to bridge huh?
And the shuttle's frame resisted loads of reentries without issues.

[Skylon]

Since this thread is reflective in nature, I'd say NASA's biggest problem with the Shuttle was trying to sell the shuttle as a vehicle for routine, safe access into space. It was intended as the DC-3 (think I got the aircraft right) of spaceflight. A NASA manager, Wayne Hale pointed out awhile ago in retrospect that was an insane proposition. By the time the DC-3 flew there had been numerous aircraft designs tested and flown. Before the shuttle there had been seven spacecraft designed and flown in the world. And only one (X-15) had anything close to the shuttle's profile. It should have never been proposed or sold as an "operational" vehicle.

If I had to pick one spaceflight as its most important, and most indicative of what it was capable of I'd say the first HST servicing flight and the subsequent servicing missions. HST will probably remain the most important scientific tool deployed by the shuttle, and the presence of humans saved, and maintained the capability of Hubble. These flights also highlighted the importance of humans in space.

What was the shuttle wasted on? As transport vehicle for satellites (ELV's do the job just as well) and ISS crew transport (Soyuz does the job just as well). The former actually had the worst impact in the long run as production of ELV's stopped in the US until the Challenger disaster, since "everything was going to be launched by shuttle." Thankfully the USAF had the foresight to retain some Titan rockets in the event of a shuttle disaster.

Any other thoughts along these lines?

[Winston Blake]

For all their flaws, they kept us in the manned spaceflight business and provided a glimpse of a "Buck Rogers" future, even while showing that we are either not ready for that future, or it is not viable.

It has been said often in the previous threads on space flight, but since this thread is called "overal verdict", I guess its as good a place as any to repeat it:
The Space Shuttle Program managed to design, build and operate a vehicle that had to fulfill a variety of requirements that had been handed down to NASA from the US government, on a budget that the US government set... while other parts of the US government tried to kill it every step of the way. Several of those requirements were really really stupid considering what the shuttle had been ment to be, but since this was going to be the only heavy lift launch vehicle for a while, the military insisted on them. NASA had to take the whole set of requirements or kiss their shuttle goodbye. And you know what... they actually pulled it of. They managed to build the shuttle on budget and provided relatively cheap and reliable access to space for the US and it's partners. The US government didn't want to fund alternatives or *gasp* a replacement, until there was a second accident and all of a sudden everyone just knew the Shuttle was to old, costly and dangerous to fly. Even though the orbiters had upgrades all the time. And after decades of having this great tool, people go "why does it have to cost so much? look at the other guys, they do just fine with still using Soyuz!"
Now, acknowledging fiscal realities in the current global recession is reasonable. Claiming that this is the natural state of things is something else entirely.

I agree - Skgoa's final comment can be easily amended to read 'America was either not ready for the future with its contemporary management practices, or it was not viable with its contemporary engineering capability'. I think the truth is the former case, not the latter. For every other country in the world, however, the latter is more or less true.

As I understand it, the Space Shuttle was an enormous and impressive engineering success, and a management and political screw-up. In many ways, it was designed for low initial costs, development risk, and development time, traded off against ongoing costs and risks. E.g. IIRC the multi-segment SRBs were considered lower in all three than either single-segment SRBs or liquid boosters. Yet their ongoing costs and risks are higher. The design environment included an expectation that these ongoing costs would be amortised away by high launch volumes.

The engineers can't be blamed for meeting the stringent requirements in the best way possible. It was the management, planning, and political environment that created a suboptimal design environment.

Since this thread is reflective in nature, I'd say NASA's biggest problem with the Shuttle was trying to sell the shuttle as a vehicle for routine, safe access into space. It was intended as the DC-3 (think I got the aircraft right) of spaceflight. A NASA manager, Wayne Hale pointed out awhile ago in retrospect that was an insane proposition. By the time the DC-3 flew there had been numerous aircraft designs tested and flown. Before the shuttle there had been seven spacecraft designed and flown in the world. And only one (X-15) had anything close to the shuttle's profile. It should have never been proposed or sold as an "operational" vehicle.

They must have been high off the successes of Mercury, Gemini, and Apollo. Unfortunately these were essentially experimental crash programs, racing ahead into the frontier, and their great and rapid successes seem to have distorted future planning.

[erik_t]

Especially since repeated stresses of a ballistic landing fuck up the very structure of the spacecraft, unlike a glided landing of the Shuttle.

Ballistic reentry doesn't have to be horribly stressful. Any capsule bringing humans down does have to generate significant lift anyway to keep descent speed (and deceleration) compatible with safe landing (and human life). Apollo capsule managed to decelerate at 4 gees while the shuttle decelerated at 3 gees. It's not a huge gap to bridge huh?
And the shuttle's frame resisted loads of reentries without issues.

For reasons I'd have expected to be obvious, the forces which govern deceleration scale generally as the square of the relevant lengthscale, while mass scales as the cube. The Apollo CM masses something like 6000kg, compared to a max landing weight of 104000kg for a shuttle orbiter. It's a huge gap to bridge, huh?

[Winston Blake]

Especially since repeated stresses of a ballistic landing fuck up the very structure of the spacecraft, unlike a glided landing of the Shuttle.

Ballistic reentry doesn't have to be horribly stressful. Any capsule bringing humans down does have to generate significant lift anyway to keep descent speed (and deceleration) compatible with safe landing (and human life). Apollo capsule managed to decelerate at 4 gees while the shuttle decelerated at 3 gees. It's not a huge gap to bridge huh?
And the shuttle's frame resisted loads of reentries without issues.

For reasons I'd have expected to be obvious, the forces which govern deceleration scale generally as the square of the relevant lengthscale, while mass scales as the cube. The Apollo CM masses something like 6000kg, compared to a max landing weight of 104000kg for a shuttle orbiter. It's a huge gap to bridge, huh?

...for the scenario of a dual-purpose carrier of both people and large satellites. However, someone_else was talking about a different scenario - separate crew and cargo launch. This exchange began with:

If you just have to bring back the crew and at most the engines, making a spaceplane is overkill no matter how small.

[Skgoa]

This might be of interest: http://www.bbc.co.uk/news/science-environment-14089297