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Minor Damage Found On Space Shuttle
The BBC is reporting on minor damage to the space shuttle Atlantis revealed by a 10-hour inspection in orbit. On the shuttle's right side, near where the wing joins the body, inspection revealed a 21" (53cm) line of chips in the tiles that make up the vehicle's heat shield. "...more analysis by engineers would determine whether a 'focused inspection' was needed in that specific area. If so, astronauts would use sensors to determine the exact depth of the damage to the heat shield tiles. NASA has placed the space shuttle Endeavour on stand-by to rescue the crew of Atlantis if they are endangered." The crew couldn't shelter on the ISS in case of trouble, because their orbit is higher and on a different inclination.
fingers crossed. :/
.. if they launch Endeavour to rescue Atlantis, and Endeavour suffers damage at launch?
I first saw this mentioned on Twitter. Seems like only the BBC (Great Britain) is carrying the story. Haven't seen any stories on the U.S. news websites. Have the U.S. media decided that this isn't newsworthy and are waiting for a rescue mission with Space Shuttle Endeavour (a la Apollo 13)?
Can someone speculate the feasibility of "dropping" to meet ISS?
I mean, does NASA have equipments/knowledge/training to do such maneuver?
Virtual Betting on Facebook for non-geeks.
More info here: http://spaceflightnow.com/shuttle/sts125/090512fd2/index5.html
"And Scooter, also I've got some good news about the tile damage that we saw on the starboard chine area earlier today," astronaut Alan Poindexter radioed from mission control shortly after 8 p.m.
"Oh, I'm looking forward to that. Go ahead," replied shuttle commander Scott "Scooter" Altman.
"It turns out that a focussed inspection of that area on the starboard chine is not going to be required," Poindexter reported.
"All right, you've got some happy EVA campers on that," Altman said.
wot no sig
Damn those pesky kids.
So in case of any real damage, Endeavor blasts off (piloted by a 2 Astronaut crew?), all the Astronauts on board Atlantis pack their bags and take a seat in the other shutlle and live happily ever after, which is most important of all. But what would happen to Atlantis in that case? You obviously can't tow it or land it by remote, but leaving such a large object in a (decaying) orbit could cause a lot of trouble. So what would they do? Send it to the moon à la "Space Cowboys" or give it a gentle but controlled kick, letting it crash and burn up in the atmosphere?
That's really scary! A line of cracks sounds like the entire wing is bent, not just surface damage caused by hitting a bird or something. How are they going to be able to tell if the inside of the wing is fractured? The tiles could be in perfect condition, but the wing could snap off during re-entry!
Is this really a new development that the Shuttle gets increasingly fragile or is it just the fact that since Columbia it gets checked extra carefully and therefore revealing what before just went unnoticed?
Maybe NASA could build a capsule small enough to put into the shuttle through the side hatch. One crew member initiates re-entry then rides out aero braking inside the capsule. If the spacecraft burns up the capsule falls into the air. Parachutes open automatically.
As far as I know the pilot is only needed to manually deploy landing gear. Everything else can be automatic or remotely operated.
http://michaelsmith.id.au
I think the best solution would be if Atlantis could be brought back by autopilot. If the damage is marginal (that is they THINK it might destroy the shuttle but are not sure) then bringing it back unmanned would give you the possibility (if the damage is survivable) of recouping your billion dollar plus investment.
The problem is that I am not sure that the shuttles have autolanding capability. The astronauts may have lobbied to keep NASA from giving the shuttles the ability to land themselves (or via ground control) in an attempt to keep pilots from being made irrelevant. (Throwback to test-pilot days I guess). Does anyone know if the shuttle can be landed without a human crew?
"Have Rockets Run Their Course?"
"The agriculture ministry is not in charge of Gundam" - Japanese ministry official.
Can someone explain the logic of a hypothetical rescue mission to me?
The reason a rescue mission is on standby is there are "higher amounts of space debris in Hubble's orbit". Of course in the articles I could find there are not specifics and I don't know if it was the language used by NASA or something that's been dumbed down. So the logic of sending another shuttle into the same orbital debris environment is far from apparent to me.
Looks to me like the Shuttle design was always incompetent, and we just tried to pretend it wasn't.
When we used captured German scientists we had good rocket kit. I suggest we ask Mercedes or BMW for some help in building the next one. We're already asking Rolls-Royce for help because we can't make VTOL aircraft.
Perhaps, while we're over in Europe, we could ask the French how to build a successful supersonic passenger jet, and the British how to build supersonic cars. I hear they're making a 1000 mph one......
They could have repaired the damage using the asbestos fiber filling they ripped out of Hubble's old basketball.
Set your phasers on "funky"!
I am sorry, I should read Slashdot more often. There obviously is a possiblity to remote pilot ths shuttle since STS-121: http://science.slashdot.org/article.pl?sid=06/06/30/0458246.
This is going to hurt its blue book value though.
--
Feeling slow today?
I would like to be first to salute the courage of commander Altman and the crew of Atlantis on mission STS-125.
When call was made they stepped up to the plate and were ready to make the ultimate sacrifice in the name of human knowledge.
When those they left behind look up they shall see their name written in the heavens forever, even though their lives were cut cruelly short.
God bless them all and God bless America.
It is called an orbit transfer and probably takes a bunch of fuel to accomplish. Altitude is just 1 of the issues, there's the difference in orbit declination too. I don't have the numbers in front of me, but I believe the ISS is in a very high declination orbit - probably to help Russian launches reach it easier. It is sorta like making a sharp right turn followed by a sharp left turn which is extremely fuel costly. Newton's laws are king here.
I think the shuttle needs to be nearly completely topped off with fuel to reach the ISS on a direct shot, planned.
This also explains to all the people that think we just add fuel to get the shuttle to the moon. Can't work. "Shuttle Orbiter" is the name for a reason. It isn't "Shuttle Deep Spaceship".
its heat shield is replaced after every launch as it wasn't designed to be perfect
The replacing the tiles after every launch was actually not part of the original program. Originally the Shuttle was supposed to have a 10 day turnaround time. Like, it lands, they clean it up a bit, and send it off to orbit, almost like an aircraft. You know, it is a -spaceplane-. I still have the Rockwell literature from when I was a kid on it.
Anyway, I think the first cracked or damaged tiles showed up on the first flight. Then the Challenger accident introduced even more procedures. Had we stuck to the original plans for the shuttle, and had a fleet of 10 or so, we would have had a much better STS.
I was actually pretty anti-shuttle for a while but I've come to really appreciate it. I'm actually secretly hoping that Congress will do the politically nutty thing and keep the shuttle, with incremental improvements, to sustain LEO development and recovery of in space objects, and also have the Constellation for long range missions.
This is my sig.
'Tis but a scratch.
But it's also important to note that this happened because it was the pilot who miscalculated the fuel to begin with. His flying licence was suspended as a result.
Another example of a pilot who ran out of fuel due to his own error was Varig flight 254 in 1989, when the pilot made a decimal point mistake and entered a 270 degrees heading instead of 27.0 in the autopilot, and ran out of fuel over the Amazon jungle.
Shouldn't there be escape pods on that sucker? They wouldn't have to do re-entry or nuthin, just skip off the atmosphere once to burn off a little velocity, then maintain low orbit until the Rooskies come.
``Tension, apprehension & dissension have begun!'' - Duffy Wyg&, in Alfred Bester's _The Demolished Man_
I know it was a joke, but it would work.
They'd have to bring the orbital velocity down from the 17,000+mph to 0.
The reason for the high heat is the extreme orbital velocity required to keep them up. If they reduced it to 0, when they dropped back into the atmosphere, the atmosphere itself would act like a cushion, and as they fell into the atmosphere, their own terminal velocity would slow them down gracefully.
Search around for Joseph Kittinger (jump from 102,800 feet in 1960) and Roger Eugene Andreyev (jump from 80,325 in 1962)
There are a few problems with it though.
I don't know that there's enough fuel on the shuttle to bring it down to a geosynchronous orbit. They have oms thrusters, good for changing altitude on a mission and maintaining their orbit, but not dropping so much speed.
If they brought the whole shuttle in that way, assuming in a flat orientation (bottom down, top up, 0 ground speed), it would slow down very gracefully, but once in the atmosphere they would be in a stall, and I doubt the oms engines would be able to maintain it's attitude. It may be unrecoverable once it's in the air.
If they rode the shuttle down to a low geosynchronous orbit and then jumped, they would be in very close proximity to the shuttle for a long time. There would be a huge risk of encountering the shuttle or debris as they re-entered in such close proximity to each other. Getting smacked in the head by a 2,000 ton airplane in a free fall can hurt. People would likely have a higher terminal velocity than the orbiter (the orbiter has a lot more surface area than an EVA suit), so the people would likely drop faster, but once their parachutes deployed, they'd slow dramatically, where the still falling orbiter wouldn't.
It would take a lot of planning to avoid existing debris in orbit.
It would take a lot of planning and luck to drop them anywhere close to where they'd want to land. Landing in Nevada or landing in the Atlantic or Pacific ocean would almost be a crap shoot. If they came down in just EVA suits, landing in the water wouldn't be practical.
Dropping the orbiter out of the air, even aiming for Nevada, may land in an unpredictable area. Hitting a metro area within say 1000 miles would be a bad thing(tm).
The crew don't have EVA suits with enough air to make the jump from orbit to breathable atmosphere (10k feet).
I don't believe the EVA suits carry beacons that are trackable from the ground.
Most importantly, they don't have parachutes.
This would have been something excellent to test out years ago, and they've had plenty of chances to try it out with "crash dummies" and timed/altitude parachute deployments.
Serious? Seriousness is well above my pay grade.
At least it was not in a bug in the toilet system.
Too bad duct tape is not so good with heat.
Fuck systemd. Fuck Redhat. Fuck Soylent, too. Wait, scratch the last one.
NASA should just stick one of these suckers on all the leading edges, etc.
http://tinyurl.com/q8domj
Hey, it worked for the Camaro circa 1980s, and the Shuttle is the same vintage.
1. Create giant bug deflector for Shuttle.
2. Sell giant bug deflector to NASA.
3. ?
4. Profit!
I don't know that there's enough fuel on the shuttle to bring it down to a geosynchronous orbit.
Bring it UP to a geosynchronous orbit. The shuttle usually orbits at LEOs around 5200 miles (semi-major axis). Geosync is up around 26,200 miles . (In that chart, the little blue fuzz is LEO, and the black dashes are geostationary.)
The shuttle can't attain that high an orbit, and I dont' think the shuttle can survive outside the van allen belts. When it has to deliver satellites to geosynchronous orbit they use a second stage booster out of the cargo bay.
Don't blame me, I voted for Baltar.
I don't know that there's enough fuel on the shuttle to bring it down to a geosynchronous orbit.
If they rode the shuttle down to a low geosynchronous orbit
You keep using that word. I do not think it means what you think it means. Geosynchronous
Enigma
Can they actually do that? My understanding is that the landing gear are still not remotely deployable.
I think not. I actually met one of the programmers that did the flight control software for the Buran. He used to joke, Americans put astronauts in spaceships because their remote control is not as good as ours.
This is my sig.
"I don't know that there's enough fuel on the shuttle to bring it down to a geosynchronous orbit. They have oms thrusters, good for changing altitude on a mission and maintaining their orbit, but not dropping so much speed."
WTF?????
Geosynchronous orbit is about 36000 kilometers, while Shuttle's orbit is about 300 kilomterers, AFAIR.
In any case, going UP won't help you a bit (you'll still be in an inertial orbit). You need to _reduce_ your speed essentially to zero.
That means you have to expend _the_ _same_ _amount_ of fuel that was required to lift the Shuttle in the first place.
And that's completely impossible with chemical fuels.
No, I really meant down into a geosynchronous orbit. :)
At a low orbit with 0 ground speed, the orbit will decay fast, which is what you'd want. If it went up to where it could maintain that orbit, well, it wouldn't come down very easily.
Basically, do a burn similar to their deorbit burn. Spin it around backwards, fire the main engines for about 4 minutes, flip back around, and fly home. :)
When they do the deorbit burn, they slow down by about 150mph, and the orbit decays rapidly.
They don't carry enough fuel to bring that down to 0 though.
I went looking around, and found that there was a proposal a long time ago for basically a bean bag that an astronaut could climb into. More like a big foam filled sleeping bag. It had minimal heat shielding, but if they were dropped geosynchronous, they could make it back. It'd take about 4 hours or so, trapped inside a little bag, with no light, no communications, nothing. They'd just lay in it and wonder if they were going to survive. It was dropped because of the potential psychological effects, and they never tested it from a real altitude. The only "test" was throwing a crash dummy in the bag from a bridge.
Serious? Seriousness is well above my pay grade.
I don't know that there's enough fuel on the shuttle to bring it down to a geosynchronous orbit. They have oms thrusters, good for changing altitude on a mission and maintaining their orbit, but not dropping so much speed.
Low Earth Orbit velocity is approximately 7.8 km/s. The Hubble's orbit is slightly higher, with a slower velocity of 7.5 km/s.
The delta-v capability of a space shuttle after successfully completing a launch is approximately 600 mph (0.27 km/s), depending on the weight of the payload it's carrying. Dumping all their non-essential items out the airlock before the burn might gain them something, but not nearly enough. Remember that it takes two extra rockets and a full bolt-on fuel tank to achieve that 7.8 km/s in the first place (actually 9.3 km/s with atmospheric effects).
Even if a second rocket with a payload of nothing but fuel was launched to rendezvous with the shuttle, it would still not be enough to slow down the shuttle to zero tangential velocity. Nothing as big as the Stage 1 tank has ever been boosted into orbit in a single launch. It would take many launches and lots of complicated orbital rendezvous maneuvers to refuel the shuttle enough on-orbit to achieve a 7.5 km/s burn.
And even then, Main Engine Cutoff (MECO) during launch is at T+8 minutes; the shuttle engines can't burn a full tank of fuel much faster than that (they throttle down right at the end to keep the acceleration to 3g or less, but before that it's balls-to-the-wall). I'm not sure how long it would take the orbiter to reach the atmosphere during the deorbit maneuver--the shuttle would start to fall to the Earth immediately, in an arc that would end up perfectly vertical with respect to the ground--but 8 minutes seems like a long time. If the shuttle hit the atmosphere before the full 7.5 km/s delta-v was achieved, it would still have some tangential velocity, making for a bumpy ride, and the possibility of heating effects on unprotected surfaces.
In any case, there isn't nearly enough fuel up there to do this, and any secondary launch to bring them fuel may as well just bring a rescue capsule for the astronauts.
Thanks for the fun thought experiment, though.
For security, the MD5 hash of this message and sig is 09f911029d74e35bd84156c5635688c0.
More as in geosynchronous - traveling synchronous with the geo (ground/earth). It would just fail to maintain it's orbit, but that's the idea. :)
0 forward velocity means less friction against the air. Zinging anything across the atmosphere really quickly will ... well ... make a lot of friction, and as it flies through the thinner parts of the atmosphere, it will get hot and not slow very well.
Serious? Seriousness is well above my pay grade.
Think about what I was explaining, don't get stuck on one word.
Take a nice fast space shuttle, and bring it to 0 ground speed. Not fly up to a stable geosynchronous orbit. If you go UP, you're going the wrong way to come DOWN. As it falls and the air thickens, it'll slow down. The shuttle wasn't exactly made for it, which is why I said the other parts. It's not exactly a practical plan, but it could have been used as a contingency plan. Now their contingency plan is to launch another shuttle which at the odds will likely have a fault too.
Serious? Seriousness is well above my pay grade.
Maybe they'll cocnsider it in the future.
They could save a lot of weight if they're just riding it down.
Cargo bay doors? Ejected. :)
Nav computers (only 3 of 5 required for normal missions)? Ejected.
Extra seats? Ejected.
Storage lockers? Ejected.
2 basket balls? Ejected.
Canada Robotic Arm? Ejected.
Post flight checklist? Nah don't need that any more. Ejected.
Landing gear? Ejected.
Parachutes? Nah, I'm taking those along. Ride it down to 20k feet, and jump out of the cargo bay.
Hmmm.. They DO have parachutes now, don't they? They're used in case of low altitude failure, where they can jump out the lower door.
Serious? Seriousness is well above my pay grade.
Hmmm.. They DO have parachutes now, don't they? They're used in case of low altitude failure, where they can jump out the lower door.
No, the astronauts no NOT have parachutes.
Tesla was a genius. Edison however was a overrated hack who liked to torture puppies.
When they do the deorbit burn, they slow down by about 150mph, and the orbit decays rapidly. They don't carry enough fuel to bring that down to 0 though.
Actually, no where near 0. In a three minute burn they reduce the speed by ~300 km/h but they are still flying at around 30000 km/h.
Tesla was a genius. Edison however was a overrated hack who liked to torture puppies.
The reason for the high heat is the extreme orbital velocity required to keep them up. If they reduced it to 0, when they dropped back into the atmosphere, the atmosphere itself would act like a cushion, and as they fell into the atmosphere, their own terminal velocity would slow them down gracefully.
Actually the extreme heat is the friction against the atmosphere that is slowing them down. If you maintain orbit outside the atmosphere, there is no heat from the velocity.
If they brought the whole shuttle in that way, assuming in a flat orientation (bottom down, top up, 0 ground speed), it would slow down very gracefully
In reality it would very likely burn up due to extreme friction against the atmosphere.
Tesla was a genius. Edison however was a overrated hack who liked to torture puppies.
WTF#2 ????
"Take a nice fast space shuttle, and bring it to 0 ground speed."
One more time. To slow down the Shuttle to zero speed need to expend at least EXACTLY the same amount of fuel that you use now to lift up the Shuttle.
This mode is called 'powered descent' we used it on the Moon. But it's impossible to do it to land chemical-rocket based ship on the Earth. It might be possible with nuclear rockets, though.
"As it falls and the air thickens, it'll slow down. The shuttle wasn't exactly made for it, which is why I said the other parts."
The Shuttle was made EXACTLY for this mode. It uses air friction to dissipate orbital energy.
If you have enough engine capacity to stop at orbit relative to ground (which I presume you meant), you have enough engine capacity to simply do a powered landing. Simply turn the engines down where they just barely keep you afloat, and then turn them a bit further down, so you'll descend in a gentle and controlled way. Of course it would take a nuclear rocket, at the very least, to do that.
The shuttle was made for a lot rougher landing. That part is not a problem.
No, it isn't a practical plan, and it can't be used as a contingency plan for that exact reason.
You've seen a shuttle prior to launch, right? Ever notice that huge cylinder which the shuttle is attached to, which in fact dwarfs the shuttle itself? That's the fuel tank for the main engine, needed to bring the shuttle up to orbital speed. It's not quite enough either, but requires the help of two boosters. In order to stop from orbital speed would require just as much fuel (minus the amount used to fight air resistance and gravity at the beginning of the flight). The shuttle simply doesn't have it. In order to have it, the initial launch vehicle would need to carry all that fuel to the orbit too. We do not have the ability to send that much mass to space at a price we could afford.
Well, the alternative your proposing would require them to magically generate a tankerful of fuel and a tank to hold it from nothing.
Forget magic. Any technology distinguishable from divine power is insufficiently advanced.
Geostationary - Above the equator, Satellite remains stationary above a point on the earth. Geosynchronous - satellite is regularly above the same spot on the earth's surface (e.g. a polar orbit)
Yes they do. :)
It's the ICES Inflight Crew Escape System (ICES)
Serious? Seriousness is well above my pay grade.
That sounds an awful lot like what I said. :)
Serious? Seriousness is well above my pay grade.
Interesting. Thanks!
Tesla was a genius. Edison however was a overrated hack who liked to torture puppies.
You didn't reference my first post, did you? Follow the parents up to it.
Serious? Seriousness is well above my pay grade.
The shuttle is made to glide in with a nose up attitude until it encountered enough atmosphere to fly normally.
What I was suggesting was a flat drop until it reached enough air to fly in, then going to a nose down attitude to build up some forward air speed so the control surfaces could work.
Big big difference. One is flying in. One is taking a stalled glider (a really big one) and hoping to get up some airspeed to fly with.
The first one has a lot of speed to burn off in the atmosphere. The second could have a lot less if done properly.
Serious? Seriousness is well above my pay grade.
It takes an awful lot more fuel to make the entire space shuttle (EFT, SRB, and orbiter) lift from the ground to orbit and gain enough speed. You're working against gravity and the atmosphere. You have to reach escape velocity.
What I was suggesting was just to slow it down. That wouldn't require anywhere near the fuel for the launch. It would just burn off some speed without dragging across the atmosphere.
But yes, they don't carry enough. If it was tested and worked, they could engineer it into future plans. It's not an impossible task, and even a rendezvous with pre-launched fuel tank would be doable. Well, if they engineered for it. They don't exactly have an easy gas door to open and refuel anything with, and an EVA to attach a fresh tank isn't in the current plans.
Serious? Seriousness is well above my pay grade.
"The shuttle is made to glide in with a nose up attitude until it encountered enough atmosphere to fly normally."
No. The Shuttle is made to move nose up to dissipate most of its energy on heatshield. It's more like 'continuously slamming against a wall' than flying.
And the main failure mode is not stalling, but heatshield failure.
"What I was suggesting was a flat drop until it reached enough air to fly in, then going to a nose down attitude to build up some forward air speed so the control surfaces could work."
Let me repeat one more time: YOU CAN'T MAKE SHUTTLE 'FALL' UNLESS YOU EXPEND TREMENDOUS AMOUNT OF ROCKET FUEL. You _HAVE_ to dissipate orbital energy _somehow_ - by air friction or by firing a rocket.
What exactly is not clear to you?
Maybe they'll cocnsider it in the future.
They could save a lot of weight if they're just riding it down.
Cargo bay doors? Ejected.
Nav computers (only 3 of 5 required for normal missions)? Ejected.
Extra seats? Ejected.
Storage lockers? Ejected.
2 basket balls? Ejected.
Canada Robotic Arm? Ejected.
Post flight checklist? Nah don't need that any more. Ejected.
Landing gear? Ejected. :)
Parachutes? Nah, I'm taking those along. Ride it down to 20k feet, and jump out of the cargo bay.
Hmmm.. They DO have parachutes now, don't they? They're used in case of low altitude failure, where they can jump out the lower door.
Yeah, even with all that ejected, they still wouldn't be able to get to 7.5 km/s delta-v.
The fuel required to do that weighs about the same as 4 fully loaded shuttle orbiters.
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You don't have to yell. I'm not suggesting it can be done on this mission, or even with this shuttle. It would be interesting to test, and possibly use on future craft as a contingency method for reentry.
I don't think the current shuttle design has ever run into a stall scenario. Reentry is so well planned, they can read it off the card, and if they do it right, they'll be stopped on the mark at the end of the runway.
What I was suggesting would be bringing it in, in an effective stall, which would need to be recovered from. The forward airspeed wouldn't be there, so they'd have to get it to get the control surfaces working for landing. Well, assuming something else hadn't gone wrong.
We're talking about a shuttle that has potentially failed heat shields, so I'm throwing ideas out there that could work, but as I noted in my original post, they couldn't work due to lack of planning for the scenario and lack of available fuel.
I suspect they'll simply patch the crack and land normally. If they can't, they'll send the standby shuttle up to collect everyone, and give the broken one an impossible reentry trajectory. Something like flip for the deorbit burn with the cargo bay doors open, gear down, and hatches open, and never flip back over. Make it as dirty as possible, with as many induced heat shielding failures as possible. It would come down in a blaze of glory with any surviving parts hopefully landing in the Pacific ocean. That would be a terrible shame though, but much better than the thought of a crew of astronauts being on it when it happened.
They can't just leave it up there. It's orbit will decay, and it'll come down in an unpredictable location. That's all we need is for a crippled shuttle to come down clean, nose first, into Los Angeles or New York. Well, maybe LA wouldn't a;l that be bad. :)
Serious? Seriousness is well above my pay grade.
A powered descent like you describe would take exactly as much energy as the power ascent that brought them to their current orbit. That is, 2 giagantic solid boosters and a supply of fuel larger in volume than the craft itself. There's a good reason that we've always used aerobraking to recover spacecraft: it's flipping expensive to do a powered recovery.
"Because Science" is one step from "Because old book". Try "Because of my experiment testing my falsifiable assertion".
I did a little reading....
The rear OMS engines if both fired can reduce the speed by 2 ft/s/s
A deorbit burn is a change of about 100f/s to 500f/s
They carry enough fuel for 14h of OMS thrust. This is essential, since they are automatically fired constantly during flight. They are rated for 1000 on/off cycles.
Since they say their deorbit burn is approx 3 to 4 minutes, that's just about right.
A full sustained burn, with full tanks for the OMS could change the orbital velocity by 100,800f/s in 14 hours.
Assuming your number is right, and they need to bleed off 7.5km/s, that would be 24,606 feet/second,
or a 12,303 second burn,
or a 205.5 minute burn,
or a 3.4 hour burn.
I'm really glad you bothered to post it, because ... well ... I bothered to research it, and found that it's perfectly likely that they *DO* have enough fuel on board to bring their orbital velocity down to 0, and drop like a very expensive airplane shaped rock. :)
Serious? Seriousness is well above my pay grade.
They'd have to bring the orbital velocity down from the 17,000+mph to 0.
You might want to run the maths....
If they had enough energy to do a full-stop de-orbit they'd have more than enough to alter their orbit to reach the ISS... a MUCH SAFER solution...
As it is they only have enough fuel to change their inertial vector ~800 - 1200 meters/sec no where near enough for even a 2 degree orbital plane alteration let alone a full-stop de-orbit....
You need to stop watching SciFi.... it's rotting your brain.
They carry enough fuel for 14h of OMS thrust.
[citation needed]
Ezekiel 23:20
"You don't have to yell. I'm not suggesting it can be done on this mission, or even with this shuttle. It would be interesting to test, and possibly use on future craft as a contingency method for reentry."
It will never be used as a 'contingency'. If we ever learn how to build vehicles capable of powered descent, then it will be used as the primary method of landing (because it's so much nicer than aerobraking).
How about (pdf), pg 3.
"Each of the two OMS engines produces 6,000 ...
pounds of thrust. For a typical orbiter weight,
both engines together create an acceleration of
approximately 2 ft/sec2 or 0.06 g's."
"Each OMS engine is capable of 1,000 starts and
15 hours of cumulative firing. The minimum
duration of an OMS engine firing is 2 seconds."
Serious? Seriousness is well above my pay grade.
While this says that the engine is capable of a 15 hour burn it gives no indication of whether there is enough fuel on board to achieve a 15 hour burn.
--
JimFive
Please stop using the word theory when you mean hypothesis.
Yup. I'd have to assume that if they can do a 15 hour burn, that would imply that they carry enough for a 15 hour burn at launch.
But, I don't work for NASA either, so I don't have those juicy little tidbits. I can't exactly check on their fuel status. :)
Serious? Seriousness is well above my pay grade.
and then you go in ignoring the very next sentence:
14 hours of acceleration of 2 ft/s^2 and only 1,000 ft/s of delta V? Something does not match, huh? Perhaps it's because when they are talking about the engine, they are ignoring the fact that you need to stop at a gas pump from time to time.
Ezekiel 23:20
(...go on ignoring..., ...of acceleration at..., damn those typos.)
Ezekiel 23:20
Assuming your number is right, and they need to bleed off 7.5km/s, that would be 24,606 feet/second,
or a 12,303 second burn,
or a 205.5 minute burn,
or a 3.4 hour burn.
I'm really glad you bothered to post it, because ... well ... I bothered to research it, and found that it's perfectly likely that they *DO* have enough fuel on board to bring their orbital velocity down to 0, and drop like a very expensive airplane shaped rock. :)
That may be true, but 3.4 hours is much more time than a standard deorbit, and they are decelerating that entire time.
So let's see...
Hubble's orbit is at 560 km (approx).
Height of the atmosphere is 100 km, officially recognized. It actually tapers off asymptotically to nothingness; there may be a stray nitrogen molecule or two even at the Hubble's height.
The standard deorbit maneuver (to take off that tiny 500 ft/s) is performed about an hour before landing. They hit the atmosphere about 30 minutes before landing, so a very tiny deorbit burn will drop them 460 km (on a shallow parabolic path) in a mere 30 minutes. The remaining 30 minutes is filled with hellfire and gliding to the runway.
30 minutes into your proposed 2 ft/s/s OMS burn, they will have only removed about 1100 ft/s. Of course, since that's over double their deorbit burn, they will be falling much faster (steeper parabola), and it will take less than the 30 minutes to hit the atmosphere, at which point they will still have a tangential velocity of 23,506 ft/s = 7.1 km/s.
The hideous numerical integration calculation required to find out exactly when they encounter atmospheric effects with a constant burn is left as an exercise for the reader.
So yes, they might have enough OMS fuel on board to slowly burn away 7.5 km/s, if they were way out in the middle of the solar system somewhere. At 560 km off the surface, though, they need a whole lot more thrust to remove all that in the short time before they hit atmo.
"We dinnae have the POW'R, Captain!"
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A fully loaded tank.
How many tanks of fuel do they carry?
Being that everything is extremely redundantly redundantly redundant on the shuttle, I can't suspect that they'd just have one for something essential like maneuvering.
Serious? Seriousness is well above my pay grade.
The right way to do it would be up to the folks at NASA to figure out.
I believe a deorbit burn not only decelerates them, but pushes them down too. And that burn is only 3 to 4 minutes long.
It would probably work if they were put on the upside of a curve, rather than the downside. So, they'd be gaining altitude and losing ground speed, and as they start getting pulled back down, the deceleration burn could continue pretty far down towards the atmosphere.
That calculation is way beyond my skills. Back in the day, I'm sure someone at NASA could have it figured out in less than 5 minutes with a slide rule, but now I'm sure they can just plug it into the computer, and get it back in seconds.
Doesn't anyone at NASA carry a slide rule with them any more? :)
Serious? Seriousness is well above my pay grade.