Direct (Jupiter) v. Ares...the debate continues

[dougkeenan]

I'm pessimistic when I read Ares will shake its crew to pieces.

 

[Kyle]

Apollo had really bad Pogo to Doug, And I mean bad, 13 cut off an Engine it was so bad.

 

[Moonwalker]

The question is who believes that Ares might shake its crew to pieces. It's people not being involved in the development as far as I know and so it's disinformation.

Developing a new system usually is accompanied by challenges which seems to fade into obscurity by hobby- engineers. NASA has a good track of resolving technical challenges.

Ares will fly and that properly as intended...

 

[dougkeenan]

My understanding is the TO alarm (worse than Apollo) is rising internally from people involved in the development. We're all on the same side in that nobody wants a dead crew, not even "hobby-engineers."

 

[Moonwalker]

Which involved people do you mean exactly? Any serious source/names?

 

[dougkeenan]

This article says "analyses conducted by NASA" so I don't have any names.

Are you implying the problem doesn't exist?

 

[Moonwalker]

Are you implying the problem doesn't exist?

Of course not

I imply that developing a new system always is accompanied by challenges. Possible osscilations is one of some challanges. The same article you posted also shows that there are several possible solutions already to limit the osscilations. That's what engineering is about.

NASA always faced challenges during development. When the Space Shuttle was developed in the 70's, its main engines even exploded during tests. If such an accident would happen on Ares too, just imagine how articles would look like. Also remember the pre- Mercury era. It was a success when rockets even cleared the launch tower without exploding.

NASA won't and isn't going to launch an unsafe or even deadly system. They even won't put it together and carry it to pad 39 if osscilations and other porblems would still exist. There are no NASA people who say or believe NASA is doing the opposite this time. It's all just about challenges which are being reviewed, testet and fixed as usual.

"I hope no one was so ill-informed as to believe that we would be able to develop a system to replace the shuttle without facing any challenges in doing so."

Michael Griffin, NASA administrator

 

[GregBurch]

NASA won't and isn't going to launch an unsafe or even deadly system.

Huh? They've done it over 120 times. It's called the STS. Twice it killed its whole crew.

Your respect for NASA's authority and competence is ... well, misplaced.

 

[Zatnikitelman]

A space vehicle needs to be designed to meet the mission requirements, not the ever-weaker launch vehicle. NASA should have designed Orion, then said: "Ok, what kind of rocket to we need to stick under this thing to put it into Orbit?" Not: "We got some half-assed design here, how do we design a capsule that fits the rocket."
Orion should NOT have ever had to have been lightened. There is going to be some give and take with the rocket vs. the payload on something like this, but it shouldn't be anywhere near this extreme.
Orion is being literally hacked to pieces because of a stupid design that should never have been allowed to pass the first design review!

 

[Kyle]

For the sake of Visual idea of Jupiter, I made this. I doesn't seem like a far fetched Idea.

 

[Andy44]

Greg, I think NASA is stuck in the "Golden Age" fallacy. It thinks that it has to re-do Apollo in order to regain lost glory. Times have changed. Apollo teaches us much, but you can't replicate it completely.

 

[Moonwalker]

Huh? They've done it over 120 times. Twice it killed its whole crew.

They've done so one time. The Challenger disaster was caused by a wrong decision, and not by an unsafe launch system. The Columbia disaster was caused by a potential risk which is part of the STS design but also part of the risks of manned space flight.

Space flight never will be 100% safe (the STS is 98,37% safe still). But NASA also won't launch Ares if its first stage would oscillate the crew to death.

Your respect for NASA's authority and competence is ... well, misplaced.

...in your poinf of view.

Astronauts loved and still love to fly with the Space Shuttle. Barbara Morgan took a seat although she saw the Challenger accident in person while her friend Christa Mcauliffe died. Eileen Collins flew before and past STS-107: "we don't stop flying because we have accidents". That's what NASA people think, rather than Orbinauts. Guess who has more skills to be able to assume such things correctly...

 

[Urwumpe]

Guess who has more skills to be able to assume such things correctly...

Usually experts outside the program.

We will not stop flying because we have accidents is right and valid - but closing both eyes to problems is not valid. NASA did much stuff wrong since the 1980s, which resulted finally in NASA depending on Constellation to survive in it's current form.

But exactly THAT is not the goal. Nobody pays NASA for conservation, NASA has to fulfill goals in engineering, education, space access and basic research. And this can of course mean, that NASA has to change more, as it does today. The Shuttle program already suffered for conserving the Apollo program institutions.

 

[GregBurch]

They've done so one time. The Challenger disaster was caused by a wrong decision, and not by an unsafe launch system. The Columbia disaster was caused by a potential risk which is part of the STS design but also part of the risks of manned space flight.

Space flight never will be 100% safe (the STS is 98,37% safe still). But NASA also won't launch Ares if its first stage would oscillate the crew to death.

Ice and debris from the normal launch operation causing fatal damage to the TPS is 100% foreseeable and is a design flaw built into the system from the first day.

I don't think NASA will launch Ares I with an oscillation problem that will shake the crew to death -- and I don't think anyone is suggesting they will. However, at this point, the oscillation problem is at a fatal level and was very, very foreseeable. The kind of harmonic vibration that causes it is pretty much a first-year mechanical engineering problem, wouldn't you agree?

The pogo problems with the Saturn V are distinguishable. The Saturn V was designed and built with a very large margin of throw weight from the beginning, so dealing with the pogo problem was something the over-all system design could tolerate. Ares I is currently unable to loft the design weight of the Orion vehicle. Where is NASA going to get the margin to put in the fix for the oscillation problem?

And while I'm at it, where the hell, if NASA was so dead-set on reviving Apollo era concepts, is the Saturn I in all of this? What a great rocket -- better in some ways than the Saturn V (and historically unappreciated, I think)!

Why not revive some of the design concepts from it?

...in your poinf of view.

Astronauts loved and still love to fly with the Space Shuttle. Barbara Morgan took a seat although she saw the Challenger accident in person while her friend Christa Mcauliffe died. Eileen Collins flew before and past STS-107: "we don't stop flying because we have accidents". That's what NASA people think, rather than Orbinauts. Guess who has more skills to be able to assume such things correctly...

Jeesh, don't be so literal-minded. I'm actually pretty impressed with the work that was done to get STS into a more safe flight regime after Columbia. The larger point was that the STS was a kludgey design to begin with, with some very significant design compromises that ended up causing safety issues built into it.

Before STS-1, Max Faget (who I had the pleasure of meeting once) told a briefing of astronauts that he believed that if there was ever a fatal accident with the STS, it would be with the field joints in the SRBs. That was eight years before Challenger. And yet, a completely avoidable fatal failure of the SRB field joints happened.

 

[Spicer]

I'm not an engineer at all, so here's a couple of questions for your math/engineering types out there...

The Ares 1 SRB launcher is essentially using the Space Shuttle SRB...does the STS SRB have a resonance problem? Is it cancelled out because of two SRB's? Is it not a problem, because the SRB's are attached to the ET and not directly to the orbiter?

If the debate here is Direct vs Ares...didn't Direct propose using a very similar "stick" launcher? Wouldn't the resonance problem exist there too?

 

[GregBurch]

I'm not an engineer at all, so here's a couple of questions for your math/engineering types out there...

The Ares 1 SRB launcher is essentially using the Space Shuttle SRB...does the STS SRB have a resonance problem? Is it cancelled out because of two SRB's? Is it not a problem, because the SRB's are attached to the ET and not directly to the orbiter?

If the debate here is Direct vs Ares...didn't Direct propose using a very similar "stick" launcher? Wouldn't the resonance problem exist there too?

Ares I is a "stretched" SRB with an extra segment (or segment-and-a-half, now, if memory serves) (actually, with lots of other changes). As a moment of playing with different size metal tubes will demonstrate, the precise size and shape of a structure like that has a big effect on the harmonics.

The Direct idea is to use a single design that is superficially somehwhat similar to the Ares V design (i.e. solid strapons alongside the main body of a shuttle-tank-derived liquid core). No "stick."

 

[Linguofreak]

• We've spent billions learning about reusability of space systems with STS. NASA developed a completely throw-away system with Ares/Orion.

STS is a joke as far as reusability is concerned. Yes, it is reusable, but refurbishment costs and times are so high that it's cheaper just to build a new expendable launcher. Columbia (and possibly Challenger too, since it was rebuilt out of one of the Structural Test Articles), should have been the only shuttle of the current design built, and all flights made with the Columbia design should have gone towards seeing what parts of the design were good and what was bad. The next shuttle built should have been totally redesigned based on the lessons learned from Columbia, and so on through a couple more prototypes until a design that could actually meet the reusability goals of the shuttle program was produced.

• NASA knew the day would come when STS would have to be retired for years, but postponed developing a successor program until the short time available became one of the major design constraints.

I wholeheartedly agree. This is in fact why Ares/Orion *can't* be reusable: It would simply take too long to go through the R&D program needed to turn out a true reusable launcher, considering that such an R&D program was never actually accomplished with STS.

• NASA spent time and money developing the X-38 to a very high level as a ACRV, which could have been easily continued on into a good crew transfer vehicle. But it was ditched so that it's Orion would have to be developed as a crew transfer vehicle.

Problem is that one of the lessons learned from STS, IMHO, is that we aren't quite ready to use lifting bodies as re-entry vehicles. Capsules are much more survivable and safer, though generally less reusable.

 

[GregBurch]

Problem is that one of the lessons learned from STS, IMHO, is that we aren't quite ready to use lifting bodies as re-entry vehicles. Capsules are much more survivable and safer, though generally less reusable.

I'd be interested to know specifically what you think would have been the issues with making the X-38 into a practical, MAINLY reusable crew transfer vehicle.

One of the things that the STS orbiter seems to do pretty well is de-orbit, reenter, fly and land pretty well (if the TPS stays intact, that is). It seems like the X-38 and a true crew-transfer vehicle derived from it ought to have been able to do this pretty well, also.

 

[Urwumpe]

The Ares 1 SRB launcher is essentially using the Space Shuttle SRB...does the STS SRB have a resonance problem? Is it cancelled out because of two SRB's? Is it not a problem, because the SRB's are attached to the ET and not directly to the orbiter?

They have the same problem, but there are two import reasons why it is no problem for the crew:

1. the resonance frequency of the SRBs is slightly different, because the structure is different.
2. the two SRBs are connected to the ET over a massive flexible bar in the intertank section of the ET, which is allowed to bend by a few cm.

You can even see the remaining vibrations though, on the surface of the ET, when you get a feed from the ET camera.

 

[Linguofreak]

And while I'm at it, where the hell, if NASA was so dead-set on reviving Apollo era concepts, is the Saturn I in all of this? What a great rocket -- better in some ways than the Saturn V (and historically unappreciated, I think)!

Why not revive some of the design concepts from it?

Amen!!!!

STS was a stupid sidetrack that gained us nothing. Bring back the Saturns!