Ares I-X Updates

[reject]

The USS became an uncontrollable useless piece of metal at separation. It had no working separation system installed, nor did it have a working J-2X engine installed.

Well the real upper stage could become an uncontrollable useless piece of metal if the J2 doesn't ignite. Which is a totally valid scenario to have to plan for. So I hope that either

a - this sep did not go as planned and NASA will sort it out, or
b - NASA anticipated this sort of sep and designed the LAS to cope with it

 

[Urwumpe]

Uncontrolled is not unstable. The USS is for example aerodynamically stable enough in 38 km altitude for the separation. The real upper stage will be the same, things get bad once you have longer coast phases.

A small fact: Almost all rocket stages are "uncontrolled" during separation. The ullage thrusters on most rockets are just thrusting, without controlling the attitude. even the hot staging rockets are pretty uncontrolled, since you can't gimbal the engine immediately after staging, a few seconds of uncontrolled flight are normal before you can start to use the control loops. Only few stages have verniers or RCS for keeping them stable, most control during separation happens by two factors: Guide rails or getting distance between the stages as fast as possible.

 

[Moonwalker]

Well the real upper stage could become an uncontrollable useless piece of metal if the J2 doesn't ignite.

Which would cause an abort.

A small fact: Almost all rocket stages are "uncontrolled" during separation. The ullage thrusters on most rockets are just thrusting, without controlling the attitude. even the hot staging rockets are pretty uncontrolled, since you can't gimbal the engine immediately after staging, a few seconds of uncontrolled flight are normal before you can start to use the control loops. Only few stages have verniers or RCS for keeping them stable, most control during separation happens by two factors: Guide rails or getting distance between the stages as fast as possible.

Hot staging, separation motors etc. is a kind of control, although limited. The USS had none of it + the SRP separation was lame. Not getting distance between the stages as soon as possible was the basic cause of the USS movement I think.

Btw, what happens in orbiter during staging always is a bit unrealistic. I may risk to mention that Orbiter is quite a "static" simulator as soon as something happens without thrust within the atmosphere.

 

[Urwumpe]

Hot staging, separation motors etc. is a kind of control, although limited.

No it isn't. You can't keep the attitude with them, you are just pushed in the direction you are just now pointing, regardless what this attitude is.

 

[C3PO]

Hot staging, separation motors etc. is a kind of control, although limited.

No. Ullage motors replace gravity to avoid cavitation in the turbopump during 2'nd stage ignition. They do not provide any control.

The USS had none of it + the SRP separation was lame. Not getting distance between the stages as soon as possible was the basic cause of the USS movement I think.

You should read my post more closely. You just agreed with most of what said in my first post today.
If you look closely at the time between BDM firing and BTM firing, there isn't much movement between the frustum and the forward skirt extension. I would have imagined that the separation would be more obvious. The NASA animation shows separation from another angle, and it may use exaggerated velocities. The released test footage has too many gaps to say anything for certain.

Btw, what happens in orbiter during staging always is a bit unrealistic. I may risk to mention that Orbiter is quite a "static" simulator as soon as something happens without thrust within the atmosphere.

That is an addon issue, not an Orbiter issue. Residual thrust can be added to all dll based addons, but this would add a lot of code to produce residual thrust, followed by more code to solve the problem of residual thrust. :lol: Not very efficient. Making addons is hard enough without adding things like this, and 99% of the users wouldn't even notice them. If someone made a 100% realistic addon with all the engineering problems in space craft construction, there wouldn't be a single person on this forum that would be able to get it into orbit.

 

[Andy44]

The USS became an uncontrollable useless piece of metal at separation. It had no working separation system installed, nor did it have a working J-2X engine installed.

That doesn't mean it shouldn't fly nose-first. If it's nose-heavy, or has high-drag devices near the aft end (like fins), for instance, a dumb piece of metal will fly in a very stable attitude, just like a dart towards a dartboard.

In the event the J2X doesn't ignite, it is desirable to have the capsule to be at a certain angle of attack before firing the LES to ensure the greatest chance for a survivable abort.

While I am no expert, it seems reasonable to design the LES to work best when the capsule is at a low angle of attack. Looking at it from the other direction, it's easier to build a reliable LES if you can limit the range of angles of attack you expect it to operate in.

And in any case, the stage has to stay nose-forward for at least a few seconds to get good separation before J2X ignition.

People are free to believe that there could be some kind of "secret" on the other side of the booster (while NASA released photos of the lower dented part of the booster). That's just another speculation I don't like to become a part of.

Again, you are taking arguments personal, and backhandedly accusing those who argue with you of being conspiracists or something.

Your affection for this program is leading you to take a combative stance in every discussion. Relax. Not everyone is out to prove you wrong.

 

[C3PO]

Your affection for this program is leading you to take a combative stance in every discussion. Relax. Not everyone is out to prove you wrong.

:hesaid:

"Constellation is crap" vs. "NASA knows everything" isn't a discussion. Those are just unsupported statements. I'm not that interested in statements.

 

[Kyle]

I don't see a real reason for this thread to be around other than booster recovery which already has been completed. As expected the 'Constellation sucks' argument is occurring or will occur shortly. Perhaps we can make a topic called 'Ares I-X post flight result and discussion' mods can go ahead and unsticking this too! Thanks!

 

[RisingFury]

I don't see a real reason for this thread to be around other than booster recovery which already has been completed. As expected the 'Constellation sucks' argument is occurring or will occur shortly. Perhaps we can make a topic called 'Ares I-X post flight result and discussion' mods can go ahead and unsticking this too! Thanks!

What's wrong with this one?

 

[tl8]

I don't see a real reason for this thread to be around other than booster recovery which already has been completed. As expected the 'Constellation sucks' argument is occurring or will occur shortly. Perhaps we can make a topic called 'Ares I-X post flight result and discussion' mods can go ahead and unsticking this too! Thanks!

Please try and refrain from discussing what mods should or shouldn't do in public

Secondly feel free to just PM a mod to unsticky this thread.

Thirdly if you have a problem with a post please use the Report Post feature. This will ensure that every mod can see the problem post.

Thanks
O-F Staff

 

[jathey88]

Gimbal

Does anyone know how the SRB motor gimbals? I watched the launch and saw the rocket push over and was wonder how it did that.

 

[Andy44]

Does anyone know how the SRB motor gimbals? I watched the launch and saw the rocket push over and was wonder how it did that.

http://en.wikipedia.org/wiki/Space_Shuttle_Solid_Rocket_Booster#Thrust_vector_control

 

[reject]

Which would cause an abort.

*sigh* What did I say in point (b) ?

 

[Chutli]

Ares I-X Photos The Big Picture

 

[Andy44]

Wow, great photos.

The photo of the train led me to do some googling as a railfan; turns out that NASA has it's own Class III railroad with 3 Electromotive Division (EMD) SW1500 switcher locomotives, including engine number 3 shown in the photo.

 

[Belisarius]

May I just speculate a moment here? That this is the last flight of Ares I, that the SRBs have no future, and that in fact NASA (or rather their paymasters the US govt) has given up on manned spaceflight for good.
It seems that the future of human space exploration is with China and/or the private sector.
Your thoughts?

I hope this isn't off-topic, but I don't really know where else to put it, if not a new thread.

BTW the Boston Globe photos were really spectacular.

 

[C3PO]

May I just speculate a moment here? That this is the last flight of Ares I, that the SRBs have no future, and that in fact NASA (or rather their paymasters the US govt) has given up on manned spaceflight for good.
It seems that the future of human space exploration is with China and/or the private sector.
Your thoughts?

I think you know something we don't. And have you heard of craft called "Soyuz"?

I've been listening to yesterday's Ares1-X media event and I think it poses more questions then it answers.
Everything that "failed" was due to the differences between Ares1-X and Ares1. Doesn't this make the test useless? Apart for the aerodynamic shell, there aren't many similarities between both vehicles.
The 1'st stage doesn't have the same CoG as a 5-segment. I guess simulating the burnt fuel would be difficult, and the data recorders do have to be placed somewhere on the 1'st stage.
But the USS doesn't make any sense at all. It has 130k lb of ballast, so it should be possible to get a similar CoG to the real thing. Instead NASA chooses to place 100k lb aft (along with the RoCS) and 30k lb forward. This changes almost everything about the behaviour of the stack. The stresses on the components will be different. The "stiffness" of the stack will be different. The reactions to control inputs will be different. I really would like an explanation what the reasons are for this. I'm sure there is one, but I can't see it.
To me it looks like they are testing a steel beam by breaking a wooden beam, and then calculating the difference. I just don't get this one. There has to be a better way to spend ½Bn $'s.:blink:

And the Ares1 will have active attitude control during separation. It looks like "cheaper" is out the window on this one.

 

[Belisarius]

Soyuz will be the ISS taxi for the foreseeable future... and when the ISS is retired, then nothing.

The Ares I won't ever fly, that programme is being axed even as we speak.

And you're right, the I-X test did seem a bit botched in many minor ways. Though it did prove the mega-SRB stack would fly without blowing up.

My point being, the Augustine Panel recommends putting off all manned projects so far into the future it effectively amounts to cancellation... or "death by postponement" if you will.

Just my 2 galactic credits...

 

[garyw]

Soyuz will be the ISS taxi for the foreseeable future... and when the ISS is retired, then nothing.

Don't count SpaceX out so soon.

And you're right, the I-X test did seem a bit botched in many minor ways. Though it did prove the mega-SRB stack would fly without blowing up.

You mean that a test flight found problems? Isn't that what a test flight is for?
SRB's don't "blow up" in the pretty fireworks way liquids can. There was no danger that 1-X would explode.

My point being, the Augustine Panel recommends putting off all manned projects so far into the future it effectively amounts to cancellation... or "death by postponement" if you will.

Augstinne provided OPTIONS. They have not and will not and in fact REFUSE to provide a recommendation. Option 4b is the most talked about one so far.

 

[Urwumpe]

SRB's don't "blow up" in the pretty fireworks way liquids can. There was no danger that 1-X would explode.

That is wrong, it is actually the opposite: Liquids don't explode easily, solids can have case bursts, which are far more spectacular. This explosion was caused by a SRM case burst:

There was also a Titan 3C explosion a few months before challenger, which was the first O-Ring failure resulting in a case burst.

Most fireballs you see from old liquid rockets or from challenger are produced by spraying the liquid fuel around, by aerodynamic or impact forces.

There had been many reasons to fear case bursts on the Ares I-X since the vibration and bending loads and accelerations are more extreme then on the Shuttle and outside the experience data for the SRBs.