You .. you... skeptic!

(counting youtube seconds, and backwards comparing to the SRB seconds since separation timeline) Ares 1 booster is heavier than SRB, so probably opens pilot chute and drogue a little higher, so 4 seconds longer to stabilize it would seem a good guess? You probably know more about parachutes than I do. Is it fair to guess that with only half of the designed parachute area working, it would fall a little under twice as fast? (Noting these parachutes designed for Ares 1, 1-X reported 15% heavier so also falling faster).

Bah... Guesswork... ongoing search.. Hey look! Page 12! Ares I-X Press Kit (PDF, 3.2 MB ) ... Nicolas, you are right!

pilot chute deploys at 14,940 feet, skirt separation (which pulls out the mains) at 4,500 (5,975 feet with SRB), mains deploy at 3,750, dereef at 1,140 feet.

So, similar altitude for the pilot chute, but skirt sep. is at roughly 2/3 of SRB altitude.

On the youtube video from 3 main chutes open to splashdonw was about 20 seconds, while the planned time was 27 seconds.

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Voice over added to the video
http://www.youtube.com/watch?v=KMLrQkKOzS0

the above post got my imagination going over the red... Clicking the link can only be a disappointment now...

@Slang: so full opening of the chutes should be at 1140ft. If they are all three fully open, I guess that should be enough to slow the thing down though it isn't a lot compared to the size of the thing. It just went a bit wrong this time.

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Thanks Slang and Antice. I will try the Trend Micro Housecall scan, to try to root out anything that might be on my system. Funny thing it was. When I looked at my post, the text had changed; it was highlighted in a different colour and underlined twice. I just hovered over it, without clicking, and there appeared an advert for some kind of travel agency. I logged off, then back on again and the text was back to normal and no advert was in evidence. It kind of spooked me out, just when I was regaining my confidence with this Internet thing.

With half the designed area, it should fall 1.4 times faster - drag scales as the square of the velocity.

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Apparently!

Interesting comment, Clive. Throughout history, the most aerodynamic of vehicles, whether bird, plane, or rocket, have always enjoyed a certain degree of aesthetic grace in the eyes of man.

Lo... L...? Hmm...

Two considerations: Overheating and deep vein thrombosis.

The pad's water sound suppression system is designed to reduce the supersonic shocks generated by the rocket exhaust from reflecting back upwards to the rocket body. Without it, those sonic shocks are powerful enough to damage, if not destroy, the booster.

From the link: "All three chutes initially release as designed, but one breaks free and begins trailing the rocket like a streamer. Officials say suspension lines may have snapped and caused the failure."

That's exactly what happened. Look at the top of the failed chute, with it's bluish color - that's supposed to be at the bottom of the chute, connected to suspension lines.

From the link: "Moments later, as the parachutes transition to their fully deployed state, another chute partially deflates for unknown reasons."

Same thing: Blue up top means broken suspension lines.

I can't believe someone didn't properly calculate the required riser/suspension line strengths and tolerances, as we've only been doing this sort of thing for 70 years.

But I am wondering if perhaps there's not a heat issue which isn't being addressed, i.e., the air temp coming off the SRBs isn't, say, 210 deg F which is causing the lines to fail because someone's using nylon values for ambient air temperature.

If so, ooops...

If they melted, it's easy to tell. If they simply failed at a higher temp, it may be difficult for them to tell, as the failure mode is nearly identical for lower temp, and if they fail to take the higher temp into consideration, they may miss it entirely.

Oh, well - it's only the booster. If they loose more, it'll be an expensive lession!

Cont...

Wow. There was some serious MACH+ heating going on during ascent, not to mention the additional heating when it tumbled (1:39) immediately after flameout (1:31).

Next, in the initial descent phase, which begins at 3:04, the motor is still sputtering, which may be releasing chunks of flaming propellant.

The external sputtering is last seen at 3:49, although evidence of internal sputtering continues through 4:30 and beyond.

At 4:29, the drogue cover is popped.

At 4:30, the drogue emerges.

At 4:33, the drogue is fully inflated.

The stabilization drogue did not appear to be affected by any heating issues, yet the aft end of the rocket (the hot end) is sweeping back and forth to such as degree that any heating was mixed with much longer periods of cooling.

At 4:57 the explosives are fired which releast the drogue linkage to the rocket (the drogue linkage to the mains remains intact), and allow the mains cover to exit the rocket.

By 4:59, the drogue has extracted the mains from their cannister to the full extent of their link, and the mains begin to inflate.

At 5:01, the opening shock (the largest shock to the parachutes, the suspension lines, the risers, and the body being suspended) causes the suspension lines to fail on one of the mains. The other two chutes continue to partially inflate, as per the ring-slot mechanism designed to result in a more gradual slowing before full inflation is allowed.

At 5:10 the vehicle goes behind a cloud so we can't what the heck is going on...

At 5:16, the image of the chutes emerges from behind the cloud and it appears one of the remaining two chutes is not remaining fully inflated.

At 5:19, the rocket makes contact with the ocean surface, in an apparently acceptable angle which, if the max designed velocity wasn't exceeded, would have resulted in an acceptable recovery.

Here's some thoughts:

1. I would use a slightly larger drogue (15%). The stabilization the current drogue provides is acceptable, but barely.

Notice the very slight swaying remaining in the rocket body. This indicates the drogue design was minimalized, that is, it was designed only to stabilize the rocket for main chute release.

This ignores the fact that a drogue can, and often should, also be used to go the next step, that of reducing decent velocity to slow enough such that the opening shock of the mains isn't a catestrophic event.

2. I would NOT use explosives to fire the releases for the mains. Nylon and fire don't mix, and there are many other mechanical means by which both the main hatch can be blown in a safe, non-explosive, yet highly effective manner.

As you say, they've been doing this for 70 years. How did they do it for Apollo? For the Shuttle SRB's?

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Explosives for component separation; mechanical releases for the chutes.

Given that the chutes tested perfectly from the aircraft full load tests, there might some (heat) damage component involved indeed.

Oh well, they're engineers as well, so they'll solve it.

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I (well, NASA) have an easier solution: make the Ares 1 15% lighter than the 1-X. The Ares 1-X first stage was heavier than the real thing will be due to the 5th segment simulator, and instrumentation. So the drogue will probably be sufficient as is for a fully spent 5 segment booster, since that is what it was designed for. I'm guessing the swaying was emphasized due to the simulation mass being on top.

But this drogue chute does that, doesn't it? Considering the disreefing to have more area after speed is reduced. (Drogue deploy at 518 fps, full disreef at 390 fps, main deployment starts at 340 fps)

SRB parachute deployment is described here, and to me it looks almost identical to the Ares system (link in #361), including the use of charges. Maybe I'm missing a detail here.

I say we wait until the investigation is complete before recommending changes.

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I was hoping that the onboard videos would have been released by now (similar time frame to the shuttle SRBs). I wonder if there was a camera looking "up" to record the chutes?

A nice 10 minute video made by a NASA employee giving an impression of the final days of Ares 1-X. Some nice footage from the VAB and the pad. Nothing essential, fun to watch of you have time to spare.

__________________
"Ignorance more frequently begets confidence than does knowledge" -- Charles Darwin
"Your right to hold an opinion is not being contested. Your expectation that it be taken seriously is." -- Jason Thompson
Meet the OOONG TOE.