Abort??

[350DRIVER]

CNN's Crossfire tonight discussed a few interesting things pertaining to the shuttle disaster. Norm Thagard, a former shuttle astronaut discussed the "possibility" of an "abort" , however he did not mention how this is done other than mentioning they do practice this many times over again in the sim BUT this has never happened in real life. He said he would rather continue than to abort pretty much no matter what...My question's are just out of curiousity and I could not find any information anywhere pertaining to an "abort".

1) At what point during the launch is the latest time that an abort can be done.??

2) How is this done and what is the procedure that is practiced in the sim.?

I appreciate all responses and once again the only reason I ask is out of curiousity after watching Crossfire tonight.

thanks

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[EagleRJ]

The first kind of abort is the "pad abort". This has already happened several times. The launch director or the crew can trigger an abort after the main engines start, right up until the point when the Solid Rocket Boosters are ignited. Once they are fired, the Shuttle is going somewhere. There is a slide wire system the crew can use to get off the launch tower and take refuge in a bunker, but if there is a catastrophe on the pad, I doubt if that would work. Just swinging the access gantry back into position over the hatch takes almost a minute.

From the point where the SRBs are fired to the point they are expended, there is no way to abort the flight. If the SRBs were seperated while they were still running, they would accelerate past the shuttle and incinerate it with their exhaust.

Once the SRBs burn out, the crew can perform a RTLS abort, or Return To Launch Site. This involves stopping the main engines, performing a giant split-S maneuver to point the shuttle back at the Cape and lose energy, dropping the external tank, and landing on the runway.

If the shuttle has too much momentum to make it back to the Cape, they can cross the Atlantic and land in Spain. You can hear Mission Control telling the crew on the radio when they pass certain points that dictate what their abort options are.

If they lose a main engine early after the SRBs are seperated, they can do an Abort Once Around. At that point, they don't have enough fuel to reach escape velocity, so they will burn the remaining two engines a little longer to loop once around the Earth, landing back at Cape Kennedy.

If they lose an engine later on, they can run the remaining engines longer and Abort to Orbit. They carry a little extra fuel to plan for that, and you can hear Mission Control telling them "two engine press to MECO (main engine cut off)" and a little later "single engine press to MECO", meaning that at those points, they now have enough velocity to reach orbital velocity with the remaining engines.

Their simulator is pretty elaborate. It is a regular commercial Level D full-motion sim, but it can tilt 90 degrees back, to simulate both the launch attitude and landing attitude. I'm sure all of the shuttle commanders and pilots get to practice each abort scenario numerous times- it's no different than a V1 cut for them, even though it's far more dangerous.

 

[toneal]

I also hear them say "negative return" while the three main engines are still running but the SRB's have been release (probably seconds before). What is that? They are not in space but they are pretty high up.

 

[350DRIVER]

Eagle,
Very informative response and I thank you for that insight. Sounds easier said than done I guess. Mr. Thagard's comments tonight made this "abort" after launch seem next to impossible to get a positive outcome. Very interesting to say the least.

Also the piece of foam or tile that hit the left wing>>> The size of that mass coverted to energy struck the wing at what speed from the given information.?? Any guess on the possible weight at impact with the given variables that are known or assumed.??


Thanks again,

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[EagleRJ]

I heard a NASA spokesman estimate the weight of the piece of insulation at 2.5 pounds. I guess I don't know what kind of foam it is, but it has to be tough enough to stay on the tank at supersonic speeds, so I'd guess it's definitely not styrofoam!

I think someone said the insulation came off the tank at around T+80 seconds. Keep in mind that by the time the shuttle clears the top of the launch tower, it's already going 100kts. At 80 seconds, they were probably already supersonic. Challenger exploded at T+73 seconds, as the main engines were being throttled back up after going through Mach 1.

The leading edge of the wing is a one-piece carbon mat, so it's pretty durable. The tiles just aft of it on the lower surface of the wing probably took the impact of the foam, and if some were knocked off, the edge of the next tile over would have been exposed to the slipstream, so you would have the "zipper effect" that NASA is talking about.


"Negative return" means that they are too far downrange and have too much speed for a RTLS abort- they have to pick one of the others.

 

[TDTURBO]

I don't know about the rest of you but I'm having trouble buying the "foam" theory. Tell me how a piece of foam with a delta V of 250kts max is going to hurt anything, let alone the bottom of a space shuttle wing? If the shuttle was going mach1 and the foam seperated, it wouldn't be going 0 mph right away, it would take awhile to slow down enough to have a high impact speed against the surface of Columbia. Any thoughts on this?

I should add that a NASA spokesman said that the foam has the approximate density as a styrofoam cooler.

 

[350DRIVER]

Thanks again- part of the flight program through the COEX PDP was to tour the NASA facility a few times which was pretty neat and very informative. If I remember correctly they took a Gulfstream and configured the flight deck exactly to the same specs as the shuttle (or as close as they could) and would fly it out of EFD all the time to practice prior to them doing it for real in the shuttle. It was pretty neat sitting up front and getting a hands on tour of the bird. I have nothing but praise for the entire NASA people in Houston, great hard working people... I guess I will have to go back through my notes and do a little more research.

I heard a NASA spokesman estimate the weight of the piece of insulation at 2.5 pounds.

I could only imagine how much that piece weighed at the time that it made contact with the leading edge given the "energy" it had due to the speed during the time of impact. Not too mention the other variables which I would hate to assume until all facts have been made public.

Good group of engineers down there and I have faith that they will pin point exactly what went wrong, when, how, and why.

thanks again,

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[Brother Francis]

Approximately mach 2 when the insulation separated. (Source: NASA).

KE=1/2M(V)(V)...

(V)(V)= V squared; dunno how to create mathematical notation on the boards.

V= DeltaV between the debris and the orbiter.

The kinetic energy of the collision was considerable.

Had my wife, son or daughter been aboard, considering the dedication required to earn the seat and the ultimate pinnacle of human achievement and courage that would have put them in that seat, I would be sad for myself, but happy for them.

God Bless them.

 

[dmspilot00]

The foam did hit the underside of the wing. In a newer NASA video which they have been showing today, you can see a quite significant puff of smoke resulting from the impact.

Someone on Saturday suggest that at the speed the Shuttle was traveling, a raindrop would have been enough to cause damage.

 

[EagleRJ]

Correct that the energy involved must have been considerable, since when you double the speed, you quadruple the impact energy. I don't know if the foam was the density of styrofoam, since it was still in one piece until it hit the wing. I think at M1.5-M2.0, anything the density of styrofoam would have been blown apart by the airstream.

How do you know so much about the Space Shuttle? I am really interested in it (was going to be an astronaut one day... Space Camp twice...). Was this out of a book, internet, etc.?

35 credits of college course work in Space Sciences, and I'm going back for the Master's soon! I'd like to get involved in the field sometime, too, but right now, I'm happy to be in command of a sub-orbital Saab 340 :-(

 

[atpcliff]

Hi!

NASA trains the pilots at ELP. If you're there, you can call and get a tour. I did it-pretty neat. You can sit in the flying shuttle simulator (a modified Gulfstream) and do a practice electronic flight using the HUD. The left side of the plane looks like the Shuttle, the right an aircraft.

I think the Commander has to have 1000 practice landings, and then 50? within 30 days of the launch at the planned landing runway. Obviously, all this training didn't help them as at breakup they were computer controlled.

The ELP facility also has a bunch of NASA T-38s which they practice in and fly around the country in.

Cliff
GRB

 

[empenage]

Wow:

Now this is a great topic. It seems that the time it took to review these tapes and make a desision the shuttle would be well on it's way. Right? I say that because I really dont have a clue.

Very good info. on the above posts.

 

[NEDude]

For the record

The last abort option, the Abort to Orbit, has been carried out once. The Challenger in 1985 (can't remember the mission designation but it was a spacelab mission in July 1985) lost one of its main engines about six and half minutes into the flight. The ATO option was selected and the Challenger reached an orbit approximately 30 miles lower than was planned.

 

[gubernator]

Re: For the record

The last abort option, the Abort to Orbit, has been carried out once.

More info:

http://www-pao.ksc.nasa.gov/kscpao/chron/sts51-f.htm

 

[TXCAP4228]

1/2 M V^2 (one half M V sqaured).

I did the equation in metric, got the result (which is in Newtons I think), and converted newtons to pounds. Someone please check this.

Assumptions:
Foam weight = 1 lb = 2.2KG.
Delta V = 250 miles per hour (Which may be a very low estimate) 250 mph = 400 km/hr = 111 meters/second.

so...

1.1 (1/2 of M) * 12321 (111 squared) = 13,553 newtons

13,553 newtons = 3046 pounds. (One newton = .2248 pounds)

3046 lbs of force? And if Delta V increases then the force increases exponentially....

Someone please check the math, its been years since I had a pyhsics class.

Suffice it to say that it seems like enough force to cause damage, but I'm not a rocket scientist...

 

[TDTURBO]

A 1-pound ball bearing will do allot more damage than a pound of foam. The amount of KE is irrelevant since we don't know how this force was spread out. I think there is allot of stuff they are not telling us, like the possibility of the foam being encased with a hardened shell. If it were just foam, which I doubt it was, then I can't see how this could damage anything even at a delta V of Mach 1. Since the "foam separated close to the wing, I doubt the delta V would have been close to Mach anyway. Something doesn't add up, it wasn't just foam that fell off.

 

[TDTURBO]

More info is starting to ooze out, now they are saying the "foam" was coated with ice. I can believe that a block of ice smashing into a tile was the cause, but no way foam alone. The media is also saying that it hit the wing at 1500mph.

Bullsh1t!

The shuttle was maybe only going that speed at the time, like Deftone points out, the difference in speed between the wing and foam is to short for that to happen.

I think this has happened before, ice slamming into the shuttle; they just got lucky until now.

Just like the O-ring debacle, it will become obvious that shortcuts, budget constraints, ignoring advisory committee suggestions and beaurocratic red tape are to blame once again.

If only we could learn from history, how soon we forget.

 

[Singlecoil]

...and like Challenger, this was a January launch. Anyone know what the temp and weather was at launch time?

 

[ATR-DRIVR]

Just watched fox news and they were showing a video taken from arizona when the shuttle was still in the dark. It shows something coming off and trailing behind as it falls for quite a while. This was when Columbia was either over CA or AZ at the time. Long before Texas. Additionally, the report stated that there might have been a collision between Columbia and either a meteorite or space debris prior to the de-orbit burn. In the video it is clearly seen that something fairly large has come off.....
Keep your thoughts with them....

just another ATR driver

 

[TDTURBO]

Wo! Now thats something I can believe, space debri would be a likely suspect as well. When you think about it, that would explain allot. They have been warning for years of the possibility that this could happen, if it did, how they going to fix it? They would have to make the outer skin of the shuttle bullett proof or clean up the debris. It looks like big problems on the horizon for NASA.