UPDATED - August 28th, 2011 and February 21st, 2014
1:07:10 - Here is where we start to actually save the world. Several of the things going on, starting now, have been discussed already so I will only stick to the facts that I have not yet covered. The liftoff is the first part. In the movie, before liftoff, they do a preliminary check of all flight directors. These are: Retro; Booster; ECOS; Trajectory; FIDO; EVA: CAPCOM Freedom; and CAPCOM Independence. Even though in real life several Go/No Go sequences are performed on the rockets prior to liftoff, a very short one is the last one they do. During the launching of the Swift Spacecraft the last check they did has a video Here and I do not recognize any of the terminology they use. So my guess is that Hollywood changed the order of the checks to only put the ones that might be recognizable at the end for the pleasure of the viewing audience.
An in-depth description of each of the things that were checked off before launch are:
(Parenthesis indicate actual NASA titles that correspond with the movie titles)
Retro - This is a check of the retro rockets, which are the rockets that slow the booster preparatory down so it can fall back into the atmosphere (NASA).
Booster - (Booster Engineer) The engineer monitors and evaluates the main engine. This is one of the main stations.
ECOS - This stands for "Experiment Computer Operating System", which is the primary man-machine interface. It provides for control over experiments by presenting the necessary control data over display units. How this actually helps in a launch I am not sure. (Jean and Lee, 1981).
Trajectory - (Guidance Procedures Officer?) They monitor the onboard navigation and guidance computer software. Another main station.
FIDO - (FDO - Flight Dynamics Officer) Another main station at NASA. They plan maneuvers and monitor trajectory in conjunction with the guidance officer.
EVA - The only thing I think could work for this was Extravehicular Activities meaning anything done outside the shuttle in space. Why were they checking for this now? I don't know (NASA).
CAPCOM - (Spacecraft Communicator) They are the primary control between flight control and the astronauts. This is the primary station at NASA during the shuttle flight.
They then go into some more NASA jargon stating "P.L.T.s, perform your A.P.U. pre-start". The P.L.T. is simply the pilot of the shuttle and the A.P.U. stands for Auxiliary Power Units. The statement indicates to the pilot to start warming up the engine fuel so that the shuttle is ready for launch (NASA). This usually occurs at about T-6 minutes to launch. There is a ton of other things that they left out of the movie, but again for the sake of simplicity and entertainment, I think they just cut it down to the nitty gritty.
One of the unique things about this launch is that it is a dual launch with 2 shuttles at the same time. Now, I do not see anything really wrong with this except that it would take twice the manpower to monitor the shuttles. And seeing that this is a global emergency I would imagine that if they needed 2 shuttles then they would definitely send them off at the same time, although they might want to send them from different locations to avoid the shuttles crashing into each other.
While they on their initial space flight we have some more terminology. They state that they have a max cue and S.R.B. What a "max cue" is I do not know and I don't think that NASA does either.
UPDATE: An anonymous comment suggested that "max cue" may actually mean "max Q". The Max-Q is where the air pressure pushing against the shuttle as it ascends reaches its maximum. This is a similar effect as when you hold your hand out of a car window. "Q" stands for the dynamic pressure of the air (aerospaceweb.org). This is likely a misprint in the subtitles as this seems to make complete sense in the scene.
The SRB on the other hand is the Solid Rocket Boosters and they were released at the time of the announcement, about 125 seconds after launch (Spaceline). In the movie the external tanks (ETs) are released in conjunction with the SRB's and then the main engines shut down shortly after that. In reality when the SRB's are released the external tanks remain connected to the shuttle until engine shutdown. They are then released about 18 seconds after that (NASA). So essentially everything does not fall off of the main shuttle all at once. It comes off in stages. After the boosters separate, they then state "single engine (ok), press, demi-go." Now demi-go is another phrase that does not seem to have made it anywhere in the greater world. So whatever that is I also do not know.
So, overall the launch sequence makes sense and although it was shortened it seemed pretty close to real life. My only question is, did they really make up terminology, since I can not find it anywhere, and if they did, why?
- Russian Space Junk
(AKA Mir the intergalactic gas station) -
(AKA Mir the intergalactic gas station) -
The one major, and I mean MAJOR, problem with the space station is that there is no "artificial gravity" projector on the station. In theory, if they just rotate the station, then they will be able to produce centrifugal force against the outer surface of the space station, simulating gravity. To produce an effect similar to Earth's gravity, the station needs to rotate at a remarkable rate of speed. Also the "gravity" would be the same, and probably minimal, along all of the outer walls of the central tube but it would be the strongest furthest from the rotation axis in the jutting arms (AstroProf). So it would be impossible to "walk" along the central shaft since there would be practically no gravity there, even if it was rotating fast enough in the first place.
The purpose for the layover at Mir is to refuel the 2 shuttles, that way they have enough fuel to make it to the asteroid and back. The main problem I see with this is that when escaping the Earth's gravity, huge fuel canisters were emptied and then dropped back into the atmosphere. So very little fuel from the remaining part of the shuttle was used to get to the station. So either they left the shuttle almost empty of fuel to make it easier to get into space or the movie producers did this for dramatic effect. Um, I go with the almost empty theory because that will give me more to talk about. So when they dock with Mir there are two types of fuel they could be getting. 1. Fuel that the station holds specifically for refueling shuttles. or 2. Its own supply of fuel for supporting life and all the stations daily duties. Overall Mir is powered by rechargeable batteries that use solar power, so any fuel on the station is going to only power the propulsion system that keep the station in orbit. Mir did have multiple locations to hold the fuel, but definitely not enough fuel to act as an intergalactic gas station (NASA). Even the location of the fuel storage in the movie was inaccurate. The part that they state is the "fuel pod" is just the docking compartment on another portion of the station. So, overall this means that they had to take fuel from their own reserves to fuel the shuttles, which considering the situation is entirely possible, but would not amount to that much fuel.
The type of fuel though, is very important to the refueling process. Space shuttles typically run off the interaction of hydrogen and oxygen since that produces a tremendous amount of energy. Unfortunately they must be kept very cold so this is not the ideal fuel for long missions. Also when they are refueling the shuttles in the movie they only have one pipe of fuel, so it could not be both oxygen and hydrogen. This also eliminates a fuel called hypergolic fuel, which is a lower temperature fuel but still needs a reactant, hence 2 tubes again. The movie also eliminates the solid fuels since, it was obviously liquid they were pumping out of the station. This just leaves a petroleum based rocket fuel (NASA). Unfortunately, the type of fuel stored on Mir was deuterium so they can not be transferring petroleum fuel over. So essentially they were refueling the spaceships with fuel that either will not run the shuttle or can not operate by itself.
The interesting thing about using Mir for the movie is that the reason that Mir was brought down in real life and its destruction in the movie are actually linked. No, it's true. The space station was brought down because the systems on the station could have failed at any moment and at times several systems did fail (Space). In 1997, the station had a failure of its oxygen and cooling systems and a computer system failure. So the problems seen while transferring the fuel is not only possible, I might even expect it, if there was even a real life point to that whole sequence in the first place (UCAR.edu).
So overall the trip to Mir was pointless. The reasons include:
1. They used almost no fuel after breaking from the atmosphere.
2. The only fuel they could have transferred in the manner that they did is a petroleum based fuel and most rockets run off the interaction of hydrogen and oxygen.
3. The fuel on Mir is deuterium, definitely not petroleum based.
4. There is also no artificial gravity on the station in real life, not really a reason that the trip was pointless, just making an observation.
People seem to have a problem with the explosion of the space station. They state that there is no oxygen in space so there would be no explosion like that. The way I see it is there is oxygen on the station, enough to support several people for at least several weeks, so an explosion is going to use the oxygen from the station. Therefore, I do not see a big problem with this and I am not going to discuss this further.
- Slingshot Around -
1:20:50 - Following the explosion of the station we now must slingshot around the moon and land on the back side of the asteroid. According to the movie the slingshot will produce an effect of over 9.5g's for 11 minutes. They proceed to start this procedure by rolling the space ships so the top is on the same side as the moon. After firing their boosters, which I am assuming were filled up at the last gas station, they arrive at the back of the asteroid which is supposedly clear of debris due to the moons gravity.
Although common in science fiction, i.e. Hitchhikers Guide to the Galaxy, Star Trek, Armageddon, is it actually possible to slingshot around a planet, moon, sun to gain speed? Actually it is possible, and is used by most NASA missions. Currently there is a spacecraft on its way to Pluto, but to get there it is going to take a detour around Jupiter which will speed up the spacecraft about 9000 miles per hour (Space). They way this works is when an object is headed toward a large body, lets say Jupiter, at an oblique angle the gravity of the planet pulls the object closer, speeding it up. Using this gravity the object is then pulled around the planet and can be "shot" off into a different direction going at a far greater speed (ESA). Using the moon as the object to slingshot around is not a new idea either. All of the Apollo missions (Diagram left) were sent with a trajectory, that if they needed to, they could use the moons gravity to slingshot back to Earth (NCSSM.edu). So this idea is not at all implausible.
During the slingshot maneuver, the forces described by NASA that they will endure are 9.5 g's for over 11 minutes. What actually happened in the movie was a gradual ramping up of the g's to a little over 10 with the maximum amount of g's for only a few seconds. Humans can easily survive g's up to about 9 and the body can be trained to withstand more than that. The pilots were at least exposed to similar g-forces prior to the mission in training and I do not think that this was anything remarkable (Thinkquest.org). When you look at what actually happened in the movie, this scene is possible.
Before the brunt of the slingshot maneuver the crew flips the shuttles over. Now I found a tremendous amount of people that had a problem with this. I'm not entirely sure why. They claim that the shuttles are being flown like fighter jets but what they do not understand is that there is no atmosphere to hinder such maneuvers. Actually the way they performed the maneuvers in the movie is as close to actuality as I can imagine. You saw the attitude jets rotate the ship around and then stabilize it. No problems from me. If we were in an atmosphere and moving at 22,000 mph then I would be writing an entirely different thing. But we are not.
The last part of the trip to the asteroid involves the approach vector. Supposedly the back of the asteroid would be cleared of debris since the majority of it would be pulled down to the moon. The close proximity of the asteroid to the moon would do multiple things:
1. It would alter the trajectory of the asteroid, performing a similar slingshot effect although not as dramatic, possibly causing it to miss Earth. But where would the movie be then.
2. It would cause more debris to be ripped down off of the asteroid towards the moon.
3. It would remove a lot of debris from behind the asteroid, but at the speed that the asteroid was moving I do not think there would be a tremendous amount of difference. The debris has a shield from the moon, the asteroid, so by the time the moon's gravity could have an effect on it, the asteroid would already be passed the moon and the debris would be deflected accordingly. Also, traveling at 22,000 mph the asteroid would take about 6 seconds to pass the moon. Hardly enough time to clear all of the debris away.
So overall, this section of the movie is accurate in my opinion, except for the debris behind the moon aspect. Although, when having to approach the asteroid, the backside would be the best side to land on anyway. So no matter what the debris situation was in real life, that would be the way to go. Otherwise the space shuttle would be just another bug on the asteroid's windshield.