Why abandon shuttles?

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privateer296

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I'm curious as to why we are not taking the technology developed with the shuttle and progressing with it? I understand that we a need a viable transport thats less expensive than a 500 million dollar shuttle mission but are we not kind of heading backwards when it comes to space flight? Have there been no plans to reengineer the shuttle to make it a more cost effective means to transport? The design is afterall over 30 years old and I find it hard to believe that we cannot make considerable improvements to make it more efficient. If I am totally in the dark on this subject I welcome feedback that would be enlightening.

Thank you
 
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centsworth_II

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This Space Shuttle history may be helpful to you.

"While the Shuttle has been a reasonably successful launch vehicle, it has not met the goal of greatly reducing launch costs...."

"Original goals of the Shuttle included operating at a fairly high flight rate (roughly 12 flights per year, at low cost, and with high reliability.... and is considered by some to have failed in its original purpose."


It's funny that you say eliminating wings from a spaceship is heading backward in spaceflight design. Wings are useless in spaceflight. They don't help you get to the Moon any better, or Mars. The whole idea behind the wings was quick turnaround and reuse of the ship. And they have failed in that goal. Apparently no one has found a way around that failure. Those wings and the structures to protect them during reentry are very heavy. If you are going to spend the money (energy) to lift them into space (where they are useless), they better get you the desired turnaround time and reuse of the vehicle.
 
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privateer296

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Thank you, the link was very informative. While I understand the issues with the Shuttle as it operates now I still look at the ship as technology in its infancy. Perhaps something will come of the private sector which will make the concept of the resuable space vehicle economically viable. In its time it was s wonderful tool which probably provided much more utility than capsules could have but I don't believe that such opportunity costs has ever really figured into the budget for this ship.
 
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aphh

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centsworth_II":xul1l8yq said:
Wings are useless in spaceflight.

Wings are useless only in space, but very useful when returning, as they allow great cross-range upon landing. From Florida to California and everything in-between.

Despite the weight of wings, shuttle can still lift significant payloads and even bring back stuff from orbit! It has arms and abilities like no other spacecraft ever.

Somebody said it very well, after shuttle we won't have a ship anymore, but a ferry at best.

Second generation shuttle would not need to have large delta wing, because it could use lifting body aerodynamics where the shape of the hull provides most of the aerodynamic lift.
 
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centsworth_II

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centsworth_II":1brl50fi said:
aphh":1brl50fi said:
Somebody said it very well, after shuttle we won't have a ship anymore, but a ferry at best.
Very well said!? That statement is nonsense!
It's called the Space SHUTTLE! They could just as well have called it the Space Ferry. Same difference. Same meaning. Same function.

The the entire reason for the Shuttle's being has been to ferry people and stuff into low Earth orbit. It will take a real SPACE SHIP to go to the Moon and beyond.

Some people are getting all hung up on the method of landing. I don't give two hoots how astronauts who have been to the Moon, an asteroid, or Mars land on Earth. Just as long as it's safely done.
 
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privateer296

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I concur that we would need space ships to explore the solar system but these tools do not meet the need that an efficient shuttle would provide. I think it's kind of an apples and oranges argument. The shuttle is a wonderful tool but like all tools it has its limitations. It was never intended to go to the moon or explore mars it was intended to be a reusable space delivery vehicle. One which could provide operational support for the mission vehicles which we would use to explore the solar system. It of course has not been a panacea, it has limitations like all technology. With the exisiting design and safety concerns the once promised 12 launches a year will never happen which in turn make the vehicles less cost effective to operate. The design however was approved in 1971 and though we have made modifications it would seem that a fresh prespective with new technology would be a step in the right direction.

I merely take issue with the fact that it does not appear as if there has been a serious effort to develop the next generation of vehicle. The private sector ventures that NASA collaborated with have failed which baffles me. How can an agency which has a history of innovation suddenly fail to innovate? Two answers come to mind, will and resources. I think the will of the nation to spend resources on NASA programs is subject to vision of agency managements vision of the space program and the will of politicians who may have difficulty justifying the cost of the space program to thier constituencies but this is a discussion for another board.
 
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vulture4

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>>The whole idea behind the wings was quick turnaround and reuse of the ship. And they have failed in that goal. Apparently no one has found a way around that failure. Those wings and the structures to protect them during reentry are very heavy. If you are going to spend the money (energy) to lift them into space (where they are useless), they better get you the desired turnaround time and reuse of the vehicle.

The fuel (energy) required to lift the entire shuttle is less than 1% of the cost of a mission, while 99% is maintenance, replacement of components, and support required by this particular design. The Shuttle was designed 35 years ago, when no reusable spacecraft had ever been built. The time between then and now is longer than the time between Lindberg's flight across the Atlantic and the beginning of Project Apollo. There was never even a flying prototype, and critical design decisions were made without any flight experience with the critical systems. As a result the maintenance requirements were much higher than anticipated. There is no law of science that makes spaceflight expensive.

Going back to rockets and capsules now is like flying nothing but the Wright "A" flyer until 1940 and then declaring that heavier-than-air flight is impractical and going back to balloons! The technology demonstrator program was the first step in developing a practical reusable launch vehicle to replace the Shuttle, it cost very little compared to manned spaceflight but was canceled by Sean O'Keefe to pay for a slight overrun in the ISS. Then Shuttle and most of ISS were canceled by Griffin to pay for a grandiose but generally useless "Apollo on steroids". NASA has sacrificed the future to pay for the past.

So it might be more accurate to say that we attempted once, more than 30 years ago, to build a reusable spacecraft, and that it worked much better than we had any right to expect, but wasn't perfect. So we gave up.
 
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dragon04

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centsworth_II":1ceqloyq said:
Wings are useless in spaceflight. They don't help you get to the Moon any better, or Mars.

While that's undeniably true, I've yet to see a capsule that lands on a runway real well. And while I think we're also taking a step backwards, we're doing so for exactly why you say... Launch costs didn't come down, turnaround wasn't consistently as good as it should have been, etc.. I would also guess that aging air frames must be taken into consideration as well. For whatever (of several very good) reasons, the STS Program needs to end. Were it to continue, that would mean essentially going back to the beginning and remanufacturing the entire program. And for what the system is capable of, we'd be wasting Taxpayer money.

I suspect that should we ever achieve the propulsive technology required to launch a vehicle to space and return it to Earth without strapping the vehicle to a huge H2/LOX tank with two bombs connected to it, "space planes" might be revisited.
 
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centsworth_II

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Arthur C. Clarke had it right in 2001: A Space Odyssey. A space plane to an orbiting space station and from there a Moon lander or other for beyond. A space plane cannot do it all.

The way I see it, we've had a first generation moon lander, a first generation space plane, and a first and maybe second generation space station. The battle now is between those who want to see a second generation space plane as the next big project and those who want to see a second generation Moon lander next.

Those who delight more in scientific discovery will be for the moon -- and later, Mars -- lander. Those who delight foremost in technological progress will be for the space plane. Too bad we can't do them both at once.
 
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tanstaafl76

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Think of the shuttles as 30 year old Italian sports cars, they are still neat and they still work but as their mileage builds up they become increasingly expensive to maintain and at some point it ceases to become worth it because the performance is not that remarkable any more. Additionally, there are some core safety issues with ice and insulating foam impacting the orbiters that, despite NASA's best efforts, have simply not been overcome (as we've seen with the latest damage to Atlantis). They've been fortunate since the Columbia accident that more serious impacts have not occurred, because trying to fix damaged tiles in orbit would be extremely difficult. Continuing the same program is asking for another such disaster to occur, it's only a matter of when.

And they call them orbiters because that's the extent of their capabilities as designed. It makes very little sense to spend such large amounts of money on maintenance on your 30-year-old Italian sports car when you can get the same performance (albeit in a less sexy package) from a new Mitsubishi. The future of the space program depends on expanding our horizons, and with the shuttles we have hit a brick wall. Orbital space flight is much more efficiently handled by traditionally stacked rockets, and at much lower cost with the private sector becoming more involved.

NASA's value to the American people in the future will not be defined by putting more things in orbit. It becomes a non-story. Think of the days of the Apollo program when Americans were glued to their TV or radio and watching or listening history being made. Fast forward to today, and even an impressive Hubble repair mission barely gets press. These missions no longer capture the imagination of the country, they MUST get back to doing that, and truly pushing the boundaries of what we know in order to re-capture that attention. Like it or not, NASA's future will be directly tied to what new and impressive things they can discover, and what technologies they develop along the way. If they commit all their resources to maintaining the shuttle program that will never get us beyond orbit, it's a slow downward spiral, and one that will eventually result in another shuttle being lost, and funding being decreased.

Designing a new fully reusable launch vehicle will take many years if it is going to be designed to do MORE than the current shuttles, which is the only reason to make one. Or alternatively, I could see a space-plane type design that utilizes scramjets to get to high speed and high altitude prior to switching over to rockets to boost it the rest of the way to orbit. This would eliminate that debris-impact-upon-launch issues of the current shuttles while preserving many of the cargo capacity benefits of the shuttle. But this would be a long-term process that may even be better handled by the Air Force. For NASA, their goal must be new exploration and discovery, and increasingly leave the routine cargo-to-orbit stuff to the private sector or military.
 
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samkent

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The fuel (energy) required to lift the entire shuttle is less than 1% of the cost of a mission, while 99% is maintenance, replacement of components, and support required by this particular design.

While the fuel is cheap the hardware is not. Does it make sense to drive an 18 wheeler to the grocery store? How many shuttle flights had very little in the cargo bay? Now that the ISS is done (almost) we don’t need that large truck to haul 6 people to the ISS. Plus we cannot put the shuttle in stasis waiting for the next government space construction project.

Now you have to look at your requirements in the next phase. They need to land 4 people and some rocks safely. So ask yourself what do you gain from adding wings to the next generation? What does it cost you in a weight penalty? I suspect a craft for 4 people and rocks would probably double in weight if you add wings and a tail and control systems. All it would give you is a landing on a runway. But it would cost you in terms of a much larger launch vehicle or 2 people and some rocks.

Who’s to say after a handful of flights NASA won’t install a controllable parasail and keep the parachute as a backup. Then they could land in NASA harbor. Most of the benefits with little cost. Would that silence the nay sayers?

P.S. the space planes will still require those nasty tiles for re entry. So you still have the damage thing to worry about.
 
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tanstaafl76

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samkent":3jotkxli said:
Now you have to look at your requirements in the next phase. They need to land 4 people and some rocks safely. So ask yourself what do you gain from adding wings to the next generation? What does it cost you in a weight penalty? I suspect a craft for 4 people and rocks would probably double in weight if you add wings and a tail and control systems. All it would give you is a landing on a runway. But it would cost you in terms of a much larger launch vehicle or 2 people and some rocks.

I think the bigger issue would be development and construction costs, which would be enormous for an entirely new shuttle-style reusable launch vehicle. When the shuttles were designed they were the most complicated machines ever built. But unfortunately the more features you have, the more things that can break! There is something to be said for simplicity and reliability when it comes to spaceflight.

samkent":3jotkxli said:
P.S. the space planes will still require those nasty tiles for re entry. So you still have the damage thing to worry about.

Not really, because the damage to the shuttles is occurring primarily due to ice and foam insulation that is a direct result of the vertical liftoff. If the space planes can take off horizontally and can efficiently use scramjets to the point at which a gigantic external fuel tank is no longer required like it is with the shuttles, the ice/foam debris damage problem goes away.
 
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samkent

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The tiles will be spending much more time in the lower parts of the atmosphere where there are things other than foam to worry about. I doubt the tiles will be pristine after each flight. Plus I think you will still have the tile inspections when you reach orbit.
At least with the capsule system you get a fresh heat shield with each flight.
 
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tanstaafl76

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samkent":3pg2zevn said:
The tiles will be spending much more time in the lower parts of the atmosphere where there are things other than foam to worry about.

Uh, like what? Bird strikes are the only issue aircraft typically face apart from bad weather (which obviously you would avoid flying your space plane in), and that is at very low altitude where such a space plane is not going to be spending much time at all, just short stints on takeoff and landing. Bird strikes are far less common than foam/ice hits on the shuttle (which happen every single launch to some extent).

The tiles will still require maintenance of course, but the point here is that by eliminating the foam/ice hits of the current configuration it would nearly eliminate the potential for craft-threatening damage upon ascent.

We're a long way from having all the technical pieces to have a functioning efficient space plane, and the cost/benefit may never pencil out, but assuming they could get it to work, it should be much safer than the shuttle.
 
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samkent

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http://www.birdstrike.org/events/signif.htm

Over 38,000 strike reports from 1,300 airports have been compiled, 1990-2001 (about 5,900 strikes in 2000). The FAA estimates that this represents only about 20% of the strikes that have occurred.

I know that the chances of a single space plane hitting birds are actually very low but you can’t totally discount it. When someone says ‘space plane’ a vision of an airplane sitting on the runway waiting to take off comes to mind. But this image is wrong. The energy needed is just too great. There will still be an external tank or carrier aircraft or both needed. This means a longer time in the lower parts of the atmosphere where impact damage is possible. In 2005 a turkey vulture decided to end it all by striking the back of the external tank of the shuttle, during a launch. That puts the odds close to 1 in 125 flights if you go straight up.
Face it placing ceramic foam on exposed surfaces traveling thousands of miles per hour in the atmosphere just goes against common sense.
 
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tanstaafl76

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samkent":19o6p1qf said:
http://www.birdstrike.org/events/signif.htm

Over 38,000 strike reports from 1,300 airports have been compiled, 1990-2001 (about 5,900 strikes in 2000). The FAA estimates that this represents only about 20% of the strikes that have occurred.

I know that the chances of a single space plane hitting birds are actually very low but you can’t totally discount it. When someone says ‘space plane’ a vision of an airplane sitting on the runway waiting to take off comes to mind. But this image is wrong. The energy needed is just too great. There will still be an external tank or carrier aircraft or both needed. This means a longer time in the lower parts of the atmosphere where impact damage is possible. In 2005 a turkey vulture decided to end it all by striking the back of the external tank of the shuttle, during a launch. That puts the odds close to 1 in 125 flights if you go straight up.

Once you light the candle on a rocket there are very limited abort options, but with a space plane if they suffered a substantial bird impact that they felt could endanger the integrity of the heat shield they could just turn around and land.

samkent":19o6p1qf said:
Face it placing ceramic foam on exposed surfaces traveling thousands of miles per hour in the atmosphere just goes against common sense.

It would be nice to have newer technology that performs just as well but is more durable, but that's not currently in the cards as far as I know. But regardless, you're comparing the rare chance of bird strike, after which a space plane could safely abort, with foam/ice strikes on the vertically-launched shuttle which happen every single launch and which have already resulted in the total loss of a mission.

But as mentioned previously, space plane development would be a long, expensive process, and I'm not sure that NASA is the best agency to handle that.
 
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docm

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tanstaafl76":d3j9gup5 said:
Once you light the candle on a rocket there are very limited abort options, but with a space plane if they suffered a substantial bird impact that they felt could endanger the integrity of the heat shield they could just turn around and land.
Actually a capsule with a LAS rocket can be 'saved' at any point from before liftoff all the way up. Hit the 'panic button' and off they go at 8 G's or more.

It's the shuttle that has very limited abort options, virtually the entire launch from SRB ignition up until the SRB's separate 123 seconds later.

As for heat shield damage from bird strikes - capsules are immune since their heat shields are covered by the service module (Apollo/Orion) or cargo trunk (Dragon). Not to mention that no tankage exists above the capsule, so no problem with foam or ice.

IMO orbital space planes can only make sense if you can develop one that is single stage to orbit using multi-mode engines, something akin to SABRE, or if the mothership first stage concept (Rutan or the new USAF model) goes 'live'.
 
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tanstaafl76

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Agreed docm, I should have been more specific, I was comparing shuttle versus hypothetical space plane. A capsule has more options than both (unless it's an Ares I atop an SRB, right?).
 
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docm

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Don't get me started on Ares I :roll:

I actually like the idea of Dream Chaser - top mounted with an LAS capability etc, on top of an Atlas. Just big enough to shuttle a decent sized crew and a bit of cargo on relatively short notice.

Not a space truck, but a space Grand Caravan ;)
 
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tanstaafl76

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But we can call it a space truck so we can use Deep Purple for a soundtrack :cool:
 
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bowman316

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Why not equip a airplane with rockets, then fly the plane as high as it can go, the point the nose up and fire the rockets to propel you into space.
It would be more fuel effecient that using the rockets to propel you straight from the ground.
 
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MeteorWayne

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Oh yeah. Fireball :) Sounds like my afternoon audio interlude, as long as the windows are closed ;)
 
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tanstaafl76

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MeteorWayne":76v4neia said:
Oh yeah. Fireball :) Sounds like my afternoon audio interlude, as long as the windows are closed ;)

Haha, I was thinking of Space Truckin' off of Machine Head, but Fireball works too :mrgreen:

bowman316":76v4neia said:
Why not equip a airplane with rockets, then fly the plane as high as it can go, the point the nose up and fire the rockets to propel you into space.
It would be more fuel effecient that using the rockets to propel you straight from the ground.

Well that's essentially what Burt Rutan and Co did and will continue to do with Virgin Galactic, they just haven't figured out how to get to orbit yet, which requires a lot more velocity than just shooting up to the edge of space and then pinwheeling down again. But the idea of a space plane is that you reduce the amount of rocket power needed to get to orbit by accelerating to very high rates of speed in the upper atmosphere using scramjet technology of some variety.
 
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dragon04

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centsworth_II":e8g8l798 said:
Arthur C. Clarke had it right in 2001: A Space Odyssey. A space plane to an orbiting space station and from there a Moon lander or other for beyond. A space plane cannot do it all.

The way I see it, we've had a first generation moon lander, a first generation space plane, and a first and maybe second generation space station. The battle now is between those who want to see a second generation space plane as the next big project and those who want to see a second generation Moon lander next.

Those who delight more in scientific discovery will be for the moon -- and later, Mars -- lander. Those who delight foremost in technological progress will be for the space plane. Too bad we can't do them both at once.

That's a reasonably fair assessment and you're right. An Orbiter is as limited in its mission as a planetary lander is, which is as limited as a vehicle that gets people from planet A to planet B.

I think my issue is that SpaceX will almost assuredly have a functional, tested, successful launch/cpasule system up and running within 3 or so years, and will have developed it more inexpensively than NASA and will launch missions at drastically lower cost than NASA can.

So IMO, Ares/Constellation is maybe a waste of money. However, a Lander that could be put on a Falcon9 and boosted into space and then mated to a Dragon for transit to the Moon would NOT be a waste of money, IMO. That keeps NASA in the 'ball game".

All the money that would be saved could be thrown into R&D for advanced propulsion, new, um..... *cough* space planes *cough*, etc.
 
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