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#101 2005-02-25 19:21:07

RobertDyck
Moderator
From: Winnipeg, Canada
Registered: 2002-08-20
Posts: 6,445
Website

Re: Delta IV Heavy and Beyond

Uhm, nooo MR. As I understand it engineers at Thiokol wrote a memo to management that it was too cold to launch. The O-rings were not designed to handle that temperature. There weren't any problems with O-rings other than temperature. Managers wanted to keep the launch rate up, so didn't want to hear that they couldn't launch on a cold winter day.

With Columbia they knew there was a problem with foam hitting the orbiter. This happened on the first launch (STS-1 April 12, 1981) and they used a military telescope in Hawaii to determine which tiles were missing. The military got upset when NASA released the pictures. This time they knew there was a problem again, but a manager chose not to ask the military to use the same telescope again. His gamble lost. That wouldn't have cost money; it was relations between two governmental agencies. Between STS-1 and STS-107 they had replaced white tiles with thermal blankets that are immune to foam strikes, and have been replacing through attrition black HRSI tiles with FRCI tiles that are 3 times as strong. They have been doing something. But it turned out a piece of reinforced carbon-carbon on a wing leading edge broke off. No one thought that could break, and there's no way the orbiter could survive re-entry without it.

One reason I'm emphasizing fiscal prudence regarding SDV is that it will be an unmanned launch vehicle. Separation of cargo and crew is a key factor for safety. Any HLLV will lift cargo. Unless you build a giant vehicle like Ares capable of directly throwing habitat and crew to Mars in a single launch, on orbit assembly means delivering astronauts in some sort of crew taxi. Shuttle-C isn't big enough, so you don't have to man rate it. That's one reason the configuration I talk about uses a single computer; no need for multiple redundant systems that are necessary for manned vehicles.

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#102 2005-02-25 20:44:43

Martian Republic
Member
From: Haltom City- Dallas/Fort Worth
Registered: 2004-06-13
Posts: 855

Re: Delta IV Heavy and Beyond

Uhhh nooo MR, you got your facts wrong. It was also called the Columbia.

The shuttle managers were under pressure to show that Shuttle was capable of living up to its unrealistic billing, so they pushed the launch schedule too hard, not costs too low. It would have taken time to roll Challenger back to the pad, disassemble the stack, disassemble the bottom half of the booster, and install a new O-Ring from Thiokol which is based in Utah.

It was about time, not so much money, and the Shuttle managers making a life-or-death assumption to prove Shuttle could be what it was promised to be.

Same deal with Columbia... NASA knew that foam striking the wings was a problem, but in an effort to "prove" that Shuttle was at least half way as good as it was promised, ignored it as a trivial risk.

Your right it is called the Columbia. However the rest of what I wrote is right though. However after the Challenger accident they re-engineered those solid buster so they use a different type seal then using those old type "O" rings design. They also re-engineered the ET tank to reduce the insulation falling off that tank during launch. I don't care how you want to rephrase it, it cost money to re-engineer something like that. These refusal to add these new safety feature like this, will put those Astronauts at risk and sooner or later your going to have an accident. That just the way it is. So it come down to deciding how important each added safety we want to add to the shuttle is or do we take the risk of something going wrong or how soon we want to maintain something shuttle. We cut corners on any of this stuff and we run the risk of having an accident.

Larry,

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#103 2005-02-26 00:17:00

Ad Astra
Member
Registered: 2003-02-02
Posts: 584

Re: Delta IV Heavy and Beyond

With Columbia they knew there was a problem with foam hitting the orbiter. This happened on the first launch (STS-1 April 12, 1981) and they used a military telescope in Hawaii to determine which tiles were missing. The military got upset when NASA released the pictures. This time they knew there was a problem again, but a manager chose not to ask the military to use the same telescope again. His gamble lost.

STS-1 lost tiles because of a pressure wave at ignition rather than a debris strike.  I'm also skeptical about the military telescope story (but then again, I was not around to witness STS-1.)

The reason NASA gave for not getting better imagery of Columbia is one of resolution.  An attempt to use spy sats to examine potential damage during STS-95 proved to be useless.  NASA managers had no reason to expect any better if they asked the NRO to point its sats on Columbia.


Who needs Michael Griffin when you can have Peter Griffin?  Catch "Family Guy" Sunday nights on FOX.

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#104 2005-02-26 12:46:03

RobertDyck
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From: Winnipeg, Canada
Registered: 2002-08-20
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Re: Delta IV Heavy and Beyond

The original design NASA intended was TSTO: a lifting body orbiter on a delta wing with fuselage fly-back lower stage. They changed to an expendable drop tank to save money after President Nixon cut their budget, and because the military wanted a drop tank; they needed military money to get any shuttle. Segmented SRBs were developed for Titan III and built by Thiokol, a Utah senator insisted the shuttle use them. NASA never considered any solid rocket safe for manned vehicles, much less a segmented solid rocket with joints immediately beside an LH2 tank. It was politics, they had to do it. I don't know what joints Titan III used for it's SRBs, but I suspect they're the same. The only change was from a tong-and-groove joint with 2 O-rings (one on either side of the tong) to an additional grove with a 3rd O-ring. The additional grove effectively makes it a labyrinth joint. The change to the seal isn't that much; they didn't get rid of the O-rings.

::Edit:: As I read this it doesn't appear clear that the change from 2 O-rings to 3 was after Challenger.

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#105 2005-02-26 15:53:18

GCNRevenger
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From: Earth
Registered: 2003-10-14
Posts: 6,056

Re: Delta IV Heavy and Beyond

I think that is probobly the best single-paragraph summery of the history of the Space Shuttle's politically-shaped design I have yet heard Robert.

The only things I would like to add are that NASA was forced by Nixon to build Shuttle to be the USAF's spaceship (until they realized it was hopeless and built Titan-IV instead) and that if NASA didn't build Shuttle (and something to use it for), there would be no more NASA.


"The power of accurate observation is often called cynicism by those that do not have it." - George Bernard Shaw

The glass is at 50% of capacity

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#106 2005-02-26 17:54:10

Ad Astra
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Registered: 2003-02-02
Posts: 584

Re: Delta IV Heavy and Beyond

TSTO shouldn't have been too hard to pull off, as long as the payload and cross-range requirements were reasonable.  To this end, the Faget-designed DC-3 would have been a perfectly good space shuttle. 

As soon as the Air Force and NASA were forced to cooperate, the shuttle was doomed.  Placing a 20-ton spy sat in polar orbit and coming back to base one orbit later is a challenging task that necessitated the shuttle configuration we all recognize today.  The shame of it all is that the shuttle was never used for this mission.

SRB's aren't necessarily bad--if NASA had gone with monolithic solids instead of segmented ones.  Aerojet could have built these monolithic boosters from its plant near Cape Canaveral, but NASA felt this was unfair because other potential contractors didn't have the facilities near the cape to build large solid motors.


Who needs Michael Griffin when you can have Peter Griffin?  Catch "Family Guy" Sunday nights on FOX.

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#107 2005-02-27 00:06:18

GCNRevenger
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From: Earth
Registered: 2003-10-14
Posts: 6,056

Re: Delta IV Heavy and Beyond

I think that it would have been harder to pull off then everybody thought at the time... no fly-by-wire, no computer-aided aerodynamic design, inferior engine turbopump materials, etc. It probobly could have flown, but I have doubts if it would have carried enough payload or have been reliable enough for weekly flights.

Yeah, having massive cross-range for the USAF and keeping development costs unreasonably low really did in what a "good" Shuttle should have been.

Large SRMs aren't a bad thing for cargo flights, but I am a little wary of putting people on them. NASA didn't use Aerojet's monolithic engines purely because of political favors however, as Thiokol is based out of Utah where a prominant senator was from.


"The power of accurate observation is often called cynicism by those that do not have it." - George Bernard Shaw

The glass is at 50% of capacity

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#108 2005-02-27 00:28:27

Ad Astra
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Registered: 2003-02-02
Posts: 584

Re: Delta IV Heavy and Beyond

I totally agree that the engineers of the time (late 60's, early 70's) had unrealistic expectations for how difficult it would be to build and operate a reusable spaceship.  While I think the Faget DC-3 would have been safer and cheaper than the shuttle, I'm certain that the flight rate would have been similar.  Without building the X-20 Dyna-Soar, there's no way we could have ever known how difficult it would be to inspect, repair and turn around a used spaceship.

Assuming that CEV will be expendable, future RLV's should take an incremental aproach. An X-20 style vehicle is a must for demonstrating RLV technologies.  The next step is an HL-20 sized vehicle launched by reusable boosters. After that we might be ready for a shuttle-sized TSTO or perhaps even an SSTO.


Who needs Michael Griffin when you can have Peter Griffin?  Catch "Family Guy" Sunday nights on FOX.

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#109 2005-02-27 00:40:01

GCNRevenger
Member
From: Earth
Registered: 2003-10-14
Posts: 6,056

Re: Delta IV Heavy and Beyond

No, I don't think incrimental "working up" would be a good idea. For starters, there would be so little in common with a recoverable ("reuseable") booster and a tiny engine-less (save for OMS/RCS) and bascially payload-less mini spaceplane and a full "Shuttle-for-real-this-time" that it would be a waste.

Another big reason is that there simply isn't a worthwhile reason to build a small "Shuttle-FRTT," that it can either efficently carry multi-ton satelites/probes, bulk rocket fuel, Lunar mining equipment, etc... or it can't.

By the time we need such a vehicle, which will be some years from now, I think that we will have sufficently advanced aerospace technology (high reliability LOX/LH2 rockets, advanced composit structures & tanks, metal heat shields) that building a large vehicle would be relativly easy.


"The power of accurate observation is often called cynicism by those that do not have it." - George Bernard Shaw

The glass is at 50% of capacity

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#110 2005-02-27 00:59:17

RobertDyck
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From: Winnipeg, Canada
Registered: 2002-08-20
Posts: 6,445
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Re: Delta IV Heavy and Beyond

Actually, the current shuttle uses fly-by-wire and the automated landing system that enabled multi-angle approach, it should be able to land itself. It also has the heat shield system that was proposed for the TSTO. If you want an incremental approach, you already have it. We now also have X-38 & HL-20 & X-33 development of lifting bodies, improvements to thermal shielding (AFRSI, DurAFRSI, FRCI), work on aerospike engines, improvements to avionics and glass cockpit, regenerable CO2 scrubber for long duration shuttle, lithium-aluminum tank, improved main engine pumps/throat and reduced chamber pressure for greater durability, and solid wall graphite/epoxy composite tank from DC-XA. This means we're ready for the next shuttle.

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#111 2005-02-27 08:59:11

GCNRevenger
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From: Earth
Registered: 2003-10-14
Posts: 6,056

Re: Delta IV Heavy and Beyond

Yes, I am stating that when the DC-3 was dreamed up, FBW didn't exsist yet, nor did much in the way of computer-aided aerodynamic design, nor materials durable enough for reuseable cryogenic rockets or non-silicon heat shields.

Yes, we have the basic technology today for Shuttle-II, metal heat shields that work well enough, SSME-sized rockets like COBRA or hydrocarbon rockets like the (canceld) RS-86 that should be reliable enough (100 firings between overhaul!). Its just a matter of money and purpose... that building anything big and hypersonic and rocket powerd will not come cheaply.

About the only really important thing we don't have yet is slush hydrogen technology, which will be vital to limiting the size of the spaceplane, even with the nice new composit cryogenic tanks. Oh, and as long as the vehicle is TSTO, then the advanced  many-chaimber aerospike engines shouldn't be nessesarry.


"The power of accurate observation is often called cynicism by those that do not have it." - George Bernard Shaw

The glass is at 50% of capacity

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#112 2005-02-28 06:18:53

SpaceNut
Administrator
From: New Hampshire
Registered: 2004-07-22
Posts: 21,678

Re: Delta IV Heavy and Beyond

It sounds from all the details given for the developement work that has been done for the past 20 to 30 years that doing any type of shuttle, spaceplane such not be that hard to do.

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#113 2005-02-28 09:24:43

GCNRevenger
Member
From: Earth
Registered: 2003-10-14
Posts: 6,056

Re: Delta IV Heavy and Beyond

The basic technologies all exsist except for slushed hydrogen fuels. However, just because what we need is not far beyond our reach, the simple scale of the contraption will ensure that it is an expensive project. Making a heavy-lift carrier plane the size of a heavy cargo plane, able to reach double the altitudes and speeds of modern jet fighters (or more!), and do it about a hundred times a year for years... and then you have to think about the spaceplane, which has to be as small as possible to minimize drag, reentry dynamics, and fuel tank mass. It has to have a heat shield that must resist at least 25-50 flights between replacements. It has to have engines that will basically never fail over the life of the vehicle with only one or two overhauls per year. It has to be able to carry a payload around 2/3rds of Shuttle's (and hence be about as big) or an ejectable crew cabin that can survive reentry on its own.

And it has to do it all and not cost more then $25M a flight nor take more then a few days to turn around between flights.


"The power of accurate observation is often called cynicism by those that do not have it." - George Bernard Shaw

The glass is at 50% of capacity

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#114 2018-09-23 09:26:59

SpaceNut
Administrator
From: New Hampshire
Registered: 2004-07-22
Posts: 21,678

Re: Delta IV Heavy and Beyond

old topic to fix
Finished the is page but still have the first 4 to go still...

Boeings Delta IV heavy was not human rated but was used to launch the orion boiler plate test while atlas V was selected by Boeing to launch the Starliner for human missions.

Altlas V was a paper rocket for the triple core as well but it was Space x that has shown the way forward it they should chose to take the existing rockets and do better but instead they have gone with creating new rockets.

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