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View Full Version : NASA Finds Flaw Could Have Doomed Another Shuttle



Maksutov
2004-Mar-23, 05:13 AM
Gears installed backwards in speed brakes could have caused a disaster during an emergency landing. Details are here (http://www.reuters.com/newsArticle.jhtml?type=scienceNews&storyID=4628266 &section=news).

Manchurian Taikonaut
2004-Mar-23, 05:49 AM
well its good they discovered the problems before something else might have errors in a real mission, lets hope they can fix probelms like this and prevent other things from happening, it will be good if NASA comes up with a new and safer design for manned missions

Brady Yoon
2004-Mar-23, 08:06 AM
so many things can go wrong; its a wonder that there haven't been more accidents.. :-?

JohnOwens
2004-Mar-23, 10:37 AM
:o OMG, that's the company my Dad used to do engineering for that made the faulty part, and it seems like it's a hyrdaulic part (they say "actuator", not specifically hydraulic, so it could be electric, especially if Sundstrand (they screwed up calling it "Sunstrand") was making it), which is what I worked on on aircraft in my own time.
At least that part must've been designed before my Dad was working there. :o :oops:

Launch window
2005-Feb-06, 03:08 AM
I heard one person remark laying off workers is where the shuttle budget savings will come from, also Jeffery Bell has this thing down as one of NASA's next big failures but his work is ofetn prone to dramatics rather than real scientific facts. There already has been some info made public, two years after the Columbia disaster, some NASA managers fear that cost-cutting measures and pressure to resume shuttle launches are jeopardizing critical safety reforms.
quoted edited

The Bad Astronomer
2005-Feb-06, 03:31 AM
Launch Window, where did that lengthy quotation come from? If it's copyrighted, please immediately remove it and replace it with a link.

Maddad
2005-Feb-06, 05:04 AM
The landing gears were in wrong? No problem. Just land the thing backwards.

Launch window
2005-Feb-06, 09:09 AM
Launch Window, where did that lengthy quotation come from? If it's copyrighted, please immediately remove it and replace it with a link.

I'm not sure what it was, I picked it up from two other space forums. One part of the quote I think it was a members post but it may have had a number of news links on it, it spoke about Confidential interviews, stuff NASA is doing well, safety concerns and what may need to be done I've removed it in case of copyright...if I find the link on the shuttle quote I'll post it

indie85
2005-Feb-06, 02:18 PM
Well its not as disasterous as the thing breaking up in the atmosphere, as we all know the shuttles pretty tough, so with the 'naughts strapped in tightly, i doubt you'd have casualties with it skimming the tarmac. Although i guess it wouldnt look good on the cameras, and you'd reck the actual craft #-o

skrap1r0n
2005-Feb-06, 10:21 PM
Well its not as disasterous as the thing breaking up in the atmosphere, as we all know the shuttles pretty tough, so with the 'naughts strapped in tightly, i doubt you'd have casualties with it skimming the tarmac. Although i guess it wouldnt look good on the cameras, and you'd reck the actual craft #-o

You would want brakes in an emergncy landing. It seems to me that an emergency landing would indicate an aborted launch. I have NOT read anything on how they would handle an emergency landing, but common sense tells me that they would need power to make one happen. First you have to orient it out of Rocket mode (mostly straight up) and get into glider mode, then orient your self on a glide path. I believe that would take power. Theres no telling how or if they could do that without power. Yep yopu would want brakes.

Andreas
2005-Feb-07, 03:07 AM
You would want brakes in an emergncy landing. It seems to me that an emergency landing would indicate an aborted launch. I have NOT read anything on how they would handle an emergency landing, but common sense tells me that they would need power to make one happen. First you have to orient it out of Rocket mode (mostly straight up) and get into glider mode, then orient your self on a glide path. I believe that would take power. Theres no telling how or if they could do that without power. Yep yopu would want brakes.
Your common sense is wrong. The Shuttle is a plane and can maneuver without engine power in the atmosphere (that's how it lands, after all). Then again, I don't see how you make the connection between that and the speed brakes. :-?

novaderrik
2005-Feb-07, 05:33 AM
i can't see why anyone thinks they can EVER make the shuttle- or any method of getting to space- 100% safe?
the launch is essentially the (barely) controlled explosion of a couple of million pounds of hydrogen and oxygen. they hit speeds of- what- 20,000 mph or something like that. they go up to an altitude of 200+ miles and then bring it back down in a barely controlled fall.
personally, i think it is a miracle they can get them off the gorund at all- much less LAND the thing 2 weeks later- and only have a 2% failure rate. i'd call that a very successful space program, especially when you consider some of the stuff they do that they make look routine- like docking with the Hubble 200 miles up while moving at 15,000 mph and changing stuff that was never meant to be changed out in orbit, for instance.
sure, they should always try to make it safer and cheaper, but it's not like the people who strap themselves into the thing don't understand and accept the risks in the name of progress.

joema
2005-Feb-07, 07:24 AM
...I have NOT read anything on how they would handle an emergency landing, but common sense tells me that they would need power to make one happen...
They do need power during certain abort phases and they have it -- it's called rockets. Both Solid Rocket Boosters (SRBs) and Space Shuttle Main Engines (SSMEs) have steerable nozzles, and are used to orient the vehicle on an abort trajectory prior to engine cutoff. After that it's a glider just like a normal landing.

If all three SSMEs fail, the SRBs alone have enough thrust and steering authority for this.

If the SRBs fail, it's loss of vehicle.

Plenty of detailed info about shuttle ascent and abort modes:

http://www.theandyzone.com/launchzone/launchzone.htm

The speed brakes mentioned are not wheel brakes but air brakes. The rudder opens in a V, providing air drag for braking. They're needed for all landings, not just emergencies.

skrap1r0n
2005-Feb-07, 05:42 PM
...I have NOT read anything on how they would handle an emergency landing, but common sense tells me that they would need power to make one happen...
They do need power during certain abort phases and they have it -- it's called rockets. Both Solid Rocket Boosters (SRBs) and Space Shuttle Main Engines (SSMEs) have steerable nozzles, and are used to orient the vehicle on an abort trajectory prior to engine cutoff. After that it's a glider just like a normal landing.

If all three SSMEs fail, the SRBs alone have enough thrust and steering authority for this.

If the SRBs fail, it's loss of vehicle.

Plenty of detailed info about shuttle ascent and abort modes:

http://www.theandyzone.com/launchzone/launchzone.htm

The speed brakes mentioned are not wheel brakes but air brakes. The rudder opens in a V, providing air drag for braking. They're needed for all landings, not just emergencies.

Thanks, I'll read that. I thought they would need power to orient the craft for either an emergency landing or to get it into position for a bail out.

edit:



You would want brakes in an emergncy landing. It seems to me that an emergency landing would indicate an aborted launch. I have NOT read anything on how they would handle an emergency landing, but common sense tells me that they would need power to make one happen. First you have to orient it out of Rocket mode (mostly straight up) and get into glider mode, then orient your self on a glide path. I believe that would take power. Theres no telling how or if they could do that without power. Yep yopu would want brakes.
Your common sense is wrong. The Shuttle is a plane and can maneuver without engine power in the atmosphere (that's how it lands, after all). Then again, I don't see how you make the connection between that and the speed brakes. :-?

The shuttle isn't a plane, it's a glider. In an emergency, you need power to orient the craft from a launch position to a relativly stable glide position. As far as the speed brake go, I was thinking of a gliders method of areodynamic control as opposed to a planes method. Gliders use spoilerons instead of ailerons. The Airbrake on the back of the shuttle is essentially a spoiler.

My comment was more about craft control failing in flight during an emergency.

Andreas
2005-Feb-07, 11:11 PM
The shuttle isn't a plane, it's a glider.
Excuse me? A glider is a plane.


In an emergency, you need power to orient the craft from a launch position to a relativly stable glide position.
Not when it's in the atmosphere, and outside there is no gliding anyway. :) From what I gather from the link joema provided, a three engine out contingency abort will still go into space since they would ride the solid boosters until they burn out. Then they roll, get rid of the tank and put it in a reentry attitude that doesn't overstress the Shuttle. In space they need the maneuvering thrusters for that, obviously.

But in the theoretical case that they separate in the lower 20 km of the atmosphere without gettting ripped to pieces, I guess they could do it all aerodynamically. I don't know if the thrusters would even be strong enough to work against aerodynamic forces.

Still, that doesn't have anything to do with the speed brake.


As far as the speed brake go, I was thinking of a gliders method of areodynamic control as opposed to a planes method. Gliders use spoilerons instead of ailerons.
Gliders use the same control methods as planes because they are planes. And spoilerons? I think that term isn't used much outside of RC planes. From the definitions I could find, that's just a flaperon at negative flap settings. Besides, that doesn't have anything to do with whether the plane has working engines or not.


The Airbrake on the back of the shuttle is essentially a spoiler.
I think the term "spoiler" applies only to devices that also influence lift. The speed brake on the Shuttle is therefore essentially a speed brake.

Evan
2005-Feb-07, 11:36 PM
The only power the shuttle needs to land is provided by the air power units to operate the hydraulics. Once it is off the SRBs it has plenty of momentum to change attitude as needed. It is also possible to fire the OMS engines within the atmosphere. They may be used above 70,000 feet. They can also be used if needed below that altitude in an emergency but it will damage the engines.

joema
2005-Feb-08, 12:11 AM
...But in the theoretical case that they separate in the lower 20 km of the atmosphere without gettting ripped to pieces, I guess they could do it all aerodynamically. I don't know if the thrusters would even be strong enough to work against aerodynamic forces...

There's no survivable separation before SRB burnout at about 30 statute miles altitude (48 km). The SRBs can't be jettisoned while firing, nor can the ET.

Until about three years ago, a triple SSME failure was loss of vehicle. Although the SRBs had enough thrust and attitude control to continue the ascent, the orbiter/ET attach struts would be overstressed and shear off. They were beefed up to handle the three-out SSME case.

Any abort maneuvering takes place above the effective atmosphere. IOW if they have a failure requiring an RTLS, they just keep headed downrange until they get above the atmosphere, then they pitch around and thrust backward to kill momentum.

That's why SSME or SRB power is required. By the time they can do abort maneuvering, they're so far away (and downrange velocity so high) they couldn't make it back without that thrust, even if they could turn around with reaction control thrusters.

The OMS engines are only 6000 lb thrust each against an orbiter weighing nearly 200,000 lbs. They just wouldn't do much.

There are multiple-failure contingency scenarios where the vehicle could be lost yet the crew might bail out. E.g, SRB sep, then one SSME fails, they start RTLS, then two more SSMEs fail leaving them without power to get back. In that case they'd reenter, establish stable gliding flight and bail out.

skrap1r0n
2005-Feb-08, 05:56 PM
The shuttle isn't a plane, it's a glider.
Excuse me? A glider is a plane.


In an emergency, you need power to orient the craft from a launch position to a relativly stable glide position.
Not when it's in the atmosphere, and outside there is no gliding anyway. :) From what I gather from the link joema provided, a three engine out contingency abort will still go into space since they would ride the solid boosters until they burn out. Then they roll, get rid of the tank and put it in a reentry attitude that doesn't overstress the Shuttle. In space they need the maneuvering thrusters for that, obviously.

But in the theoretical case that they separate in the lower 20 km of the atmosphere without gettting ripped to pieces, I guess they could do it all aerodynamically. I don't know if the thrusters would even be strong enough to work against aerodynamic forces.

Still, that doesn't have anything to do with the speed brake.


As far as the speed brake go, I was thinking of a gliders method of areodynamic control as opposed to a planes method. Gliders use spoilerons instead of ailerons.
Gliders use the same control methods as planes because they are planes. And spoilerons? I think that term isn't used much outside of RC planes. From the definitions I could find, that's just a flaperon at negative flap settings. Besides, that doesn't have anything to do with whether the plane has working engines or not.


The Airbrake on the back of the shuttle is essentially a spoiler.
I think the term "spoiler" applies only to devices that also influence lift. The speed brake on the Shuttle is therefore essentially a speed brake.

We'll have to agree to disagree then. I have spent time around glider pilots and No, they do NOT use the same method of control. Some of the older ones may use a planes method but these days, most gliders don't. A plane under power changes its wingshape wirh ailerons to make changes to it's roll orientation, Most modern gliders use spolierons to interrupt airflow, thus dumping lift on a wingsurface, not increasing or decreasing lift. Also, I fly RC planes and I can honestly say I haven't heard of spoilerons in terms of RC planes or gliders. I'm sure there are some high end RC gliders that may have them, but the 3 gliders and 2 planes I have flown didn't.

A spoileron is either a trailing edge flap that splits (opens both ways at once) or on some gliders it's actually a wall that pops up down a specified length of the wing. like an airdam to kill lift.

Furthermore, to control ANY vehicle in ultra-thin or no atmosphere will REQUIRE reactive thrust to orient itself. The shuttle is a brick till it gets inside the atmosphere.

Andreas
2005-Feb-08, 07:48 PM
We'll have to agree to disagree then. I have spent time around glider pilots and No, they do NOT use the same method of control.
Well, then my statements trump yours, because I am a glider pilot. :) Or at least pilot in training, don't have the license yet.

But I'm very interested in what the heck your glider pilot friends are flying that uses such different methods of control. :o


Some of the older ones may use a planes method but these days, most gliders don't. A plane under power changes its wingshape wirh ailerons to make changes to it's roll orientation, Most modern gliders use spolierons to interrupt airflow, thus dumping lift on a wingsurface, not increasing or decreasing lift.
Gliders, old and new, use ailerons to roll. You know, the LS8 and DG-1000 we have in our club aren't exactly old-fashioned stuff. See the three side views in LS8 data (http://www.dg-flugzeugbau.de/ls8-beschreibung-e.html) and DG-1000 data (http://www.dg-flugzeugbau.de/technische-daten-1000-e.html) to see that there are simple ailerons and separate spoilers. And for something slightly different the DG-800 (http://www.dg-flugzeugbau.de/technische-daten-dg800s-e.html) for flaperons along the whole wing and still separate spoilers.

Besides, your terminology doesn't make sense the way you use it. A "spoileron" is a control surface that acts as both spoiler and aileron. Therefore a plane with spoilerons can roll just as with pure ailerons. Actually I think true spoilerons aren't much in use outside of rudderless flying wings where they are used for yaw control, as in the B-2 (http://www.fas.org/nuke/guide/usa/bomber/b-2_10.jpg).


Furthermore, to control ANY vehicle in ultra-thin or no atmosphere will REQUIRE reactive thrust to orient itself. The shuttle is a brick till it gets inside the atmosphere.
Obviously. But further up the thread it wasn't established that abort within the denser atmosphere was practically impossible and you were talking about the speed brake anyway, which wouldn't work in space either. And really, the only need to orient the Shuttle in any way is because it wouldn't be able to handle the reentry stresses otherwise. If it were much more rugged it could "get into glider mode" (as you put it) from any orientation during and after reentry without any engine power. Which is my original point, sort of.

skrap1r0n
2005-Feb-08, 08:56 PM
<shrug> ok whatever. I know when I was in CAP the 4 gliders at the landing strip used only spoilers for control. I talked extensivly with the pilot of one of them as he was out Lt. and was my flight instructor (powered flight).

Normal rudder and elevator and spoilerons for roll control. If you have flown a glider then I will defer to your experience then.

Kaptain K
2005-Feb-08, 10:35 PM
The shuttle is a brick till it gets inside the atmosphere.
The shuttle is a brick even after it enters the atmosphere!

joema
2005-Feb-08, 10:51 PM
That's for sure. It has a glide ratio of about 3:1 (3 ft forward for 1 ft down), vs 10:1 for a light plane or 50:1 for a high performance glider.

Jorge
2005-Feb-08, 11:09 PM
That's for sure. It has a glide ratio of about 3:1 (3 ft forward for 1 ft down), vs 10:1 for a light plane or 50:1 for a high performance glider.

what would the 'glide' ration be if you add wings to a brick and drop it.(just out of ceurosity)

skrap1r0n
2005-Feb-09, 01:43 AM
That's for sure. It has a glide ratio of about 3:1 (3 ft forward for 1 ft down), vs 10:1 for a light plane or 50:1 for a high performance glider.

what would the 'glide' ration be if you add wings to a brick and drop it.(just out of ceurosity)

Depends on the wings

Jorge
2005-Feb-09, 11:01 PM
erm...
lets say the same size as a space shuttle(resized to match with the rest of the brick ofcourse)

skrap1r0n
2005-Feb-10, 12:24 AM
erm...
lets say the same size as a space shuttle(resized to match with the rest of the brick ofcourse)

32ftsq : 0