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BigJim
2003-Apr-07, 08:14 PM
One of my favorite movies is 1969's Marooned, and I believe that the science in it is 100% correct, except for a few sounds in space (and it may have been a little logistically difficult). Can anyone find any flaws in this movie?

tracer
2003-Apr-07, 09:11 PM
The only flaw in the movie was the unlucky timing of its theatrical release.

It was a movie about astronauts stranded in space in an Apollo spacecraft. It was still in its theatrical run during the Apollo 13 mission, and immediately got pulled from the theaters when the news broke of Apollo 13's in-flight emergency.

tracer
2003-Apr-07, 09:13 PM
Okay, okay, there were a couple of minor inaccuracies in the film, too.

F'rinstnace, when they showed the "quads" (the maneuvering thrusters) firing, they showed flames shooting out of them. The propellants used by the real Apollo spacecraft's reaction control system produce invisible plumes.

BigJim
2003-Apr-07, 09:32 PM
Okay, okay, there were a couple of minor inaccuracies in the film, too.

F'rinstnace, when they showed the "quads" (the maneuvering thrusters) firing, they showed flames shooting out of them. The propellants used by the real Apollo spacecraft's reaction control system produce invisible plumes.

True, but you must admit that this is mere nitpicking compared to modern movies like "The Core" and "Armageddon".

tracer
2003-Apr-07, 09:55 PM
True -- but I don't think Armageddon is a fair comparison for Marooned.

Apollo 13, however, would be a fair comparison for Marooned. And, guess what? Apollo 13 made the same mistake! The exhaust plumes coming out of the RCS quads in Apollo 13 were every bit as visible as they were in Marooned. (Although, at least in Apollo 13, they didn't look like flames.)

Senor Molinero
2003-Apr-08, 01:47 AM
Good science in both films. A+. Two of my favourites.
I'm prepared to forgive the flaming thrusters as devices for the benefit of the audience. "Hey, them thrusters aint working prop'ly!"

cyswxman
2003-Apr-08, 05:28 AM
Only mistake I can think of is when the hatch was blown, the ship "Ironman 1" should have started spinning when the hatch reached the end of it's hinge. Instead, the ship just drifted laterally for a short distance from the russian voshkod (sp?), then magically stopped.

Glom
2003-Apr-08, 12:15 PM
The propellants used by the real Apollo spacecraft's reaction control system produce invisible plumes.

I know that Aerozine 50 and nitrogen tetroxide produce invisible plumes at steady state, but don't the ignition transients usually last longer than the pulses themselves so you would see something?

tracer
2003-Apr-08, 07:31 PM
Depends -- do the ingition transients emit their own light?

Glom
2003-Apr-08, 08:47 PM
As we know, Cosmic Dave is very proud of some footage of a LM ascent that shows an APS plume, which is just an ignition transient. The LM APS used the same fuel as the RCS (it made it cheaper to use one set of tanks for both systems). The thrust levels might make a difference though.

BigJim
2003-Apr-08, 08:56 PM
I don't think there is any reason why the hypergolic propellants of the CSM RCS couldn't emit flame- remember there is no combustion taking place. Also, the audience wouldn't really understand what was going on otherwise.

tracer
2003-Apr-09, 06:04 AM
As we know, Cosmic Dave is very proud of some footage of a LM ascent that shows an APS plume, which is just an ignition transient.
Yes, but, was the plume visible because it was actually glowing slightly (like a flame), or was the plume visible because it contained some opaque particles that reflected sunlight?

Mainframes
2003-Apr-09, 10:01 AM
I think the plume is visible because there is an excess of oxidiser when the thrusters are initially fired.

Glom
2003-Apr-09, 01:43 PM
TR-201 engines produce a red cloud at first when fired on Earth because the preinjected nitrogen tetroxide reacts with the air.

BigJim
2003-Apr-09, 10:19 PM
Is TR-201 what the RCS used?

Glom
2003-Apr-10, 02:10 PM
They used the same fuel.

jamestox
2003-Apr-10, 03:08 PM
If I remember correctly, the Apollo RCS uses the same hypergolic propellents as the Shuttle RCS and OMS motors. On a postflight briefing film for one of the STS missions, I recall video of the OMS firing as shot from the payload bay windows.

When the OMS motors fired, there was a visible plume flash that lasted just long enough to see it and the astronaut narrating the video mentioned that, "that was just the ignition flash - the burn lasted for several seconds."

For Apollo 13, I thought the RCS firings were done quite well (aside from the "sound in a vacuum" business), with a nice compromise for the audience.

One of the things that REALLY impressed me on the same film was the treatment of the Saturn V launch ignition, where flame and smoke belch upwards from the MLP's opening at initial ignition and then are sucked downwards into the flame trench once the motors are fully burning! Just like the real thing.... It's a tiny point that many directors would've ignored - but showed that the effects people had done their homework.

JT

tracer
2003-Apr-11, 01:06 AM
But then, the Apollo 13 guys had to ruin it by having ignition happen at the end of the countdown, and by having the gantry arms swing away one at a time (instead of all-at-once like they do in real life).

jamestox
2003-Apr-14, 02:30 PM
Heh! Yep, you got that one right, too! Didn't think about that.

If I remember correctly, the ignition sequence typically begin at T-8.9 seconds.

Let's see... I think two or three of the nine swingarms retract at around T-30 second point..? The rest are "flight" retractions after the vehicle's liftoff. I'll have to go back and watch my Mighty Saturns - The Saturn V DVD again (a birthday present from my patient and loving wife).

JT

Glom
2003-Apr-14, 02:45 PM
The gantry arm retraction was innaccurate, but I did like that sweeping shot when the camera runs down the height of the SV as they retract one by one. Inaccurate, but aesthetic. 8)

jamestox, you're wife is extra loving to give you that. :P

jamestox
2003-Apr-14, 02:53 PM
Just checked the Apollo info at
http://www.hq.nasa.gov/office/pao/History/ap15fj/01launch_to_earth_orbit.htm

Ignition occurs at T-8.9.

Oh, and there's this tidbit from the Apollo 15 Flight Journal (above reference):

"...Readers can familiarize themselves with this subpanel through the movie Apollo 13. Two events in the film that focus on this panel are when Tom Hanks (as Jim Lovell, Apollo 13's commander) manually jettisons the Launch Escape Tower, and when the inboard engine of the S-II stage prematurely shuts down. Then we see one of the few flaws in this movie, otherwise known for its incredibly high standards of accuracy. The central light is shown to blink on and off. In reality, it simply changes from on to off or vice versa.

Dave Scott, from 1998 correspondence - "In Apollo 13, the movie, the light was purposely made to blink to get the viewers attention - the movie-makers knew the actual operation, but chose to take this license for dramatic effect (actually a pretty good license, as otherwise, the viewer would have missed the point!)."

JT

johnwitts
2003-Apr-15, 02:09 AM
A lot of the inaccuracies in these types of movie has to be deliberate. The thrusters firing madly would have looked stupid to most people had there been no flame and their operation silent. The astronauts would have been reporting something that was apparently not happening. It's OK for us space geeks to sit a gaffaw at these 'mistakes' but we also have to remember this movie was not made for us. It was made for people like my mum, people who need to see mad things happening for them to realise that mad things are happening. And because this is a movie it has to show these things happening, not merely hope that we will realise... I could say a similar thing about From the Earth to the Moon. There's a scene when Armstrong twists the stick to the side to make the LM pitch forward. We know it's wrong, but how many others know how to fly a LM?

Tuckerfan
2003-Apr-15, 05:12 AM
Jim Lovell saw Marooned shortly before leaving on Apollo 13. He liked it, and Marilyn, his wife, was rather horrified by it. Been a long time since I've seen it. Is it on DVD?

jamestox
2003-Apr-15, 05:51 AM
Tuckerfan,

According to the IMDb, Marooned is only available on VHS as of last month. That incident with Jim Lovell seeing the movie is in his book Lost Moon (The perilous voyage of Apollo 13).

On the swingarms: According to Murray and Cox's excellent Apollo: The Race to the Moon, arm 9 (the White Room) retracted at T-5 min. Three others were retracted between T-5 min and T-20 sec; the remaining five arms were 'in-flight' retracting arms "...meaning that they remained in place until after the hold-down arms had released and the vehicle was already in motion." (Apollo, pg 247)

Just think of it...the Saturn is in flight, and the 10-30 TON arms MUST disconnect, swing free of the launch vehicle on a 73-degree arc in fractions of a second, then decellarate to a stop before slamming into the umbilical tower! Again, quoting Apollo..., "The arms had given the Cape more trouble than any other item in the ground support equipment except the crawler" (Italics mine. The crawler transporter had been broken down for 6-months from June 1965 - January 1966 1 1/2 miles from the VAB during a trial run).

JT

Tuckerfan
2003-Apr-15, 06:13 AM
I hope they put it out on DVD. Amazing stuff about the launch tower. Too bad it's being left to rust away. (http://savethelut.org/)

Glom
2003-Apr-15, 11:52 AM
Jim Lovell saw Marooned shortly before leaving on Apollo 13. He liked it, and Marilyn, his wife, was rather horrified by it.

In the audio commentary by the Lovells on the DVD release of Apollo 13, Marilyn said that Marooned did actually give her nightmares, which is where Howard got the idea for that nightmare sequence.

jamestox
2003-Apr-15, 03:16 PM
I hope they put it out on DVD. Amazing stuff about the launch tower. Too bad it's being left to rust away. (http://savethelut.org/)

I didn't know about the LUT still being in existence...thought it had probably been scrapped after being cut from the MLP. I agree it needs to be preserved.

Also, did you know about one of only three remaining Saturn V's being left to rust away? (http://www.spacecamp.com/SaturnV/home.asp) This one is owned by the Smithsonian, displayed in Huntsville's US Space and Rocket Center and is the sole A.S. launch vehicle designated as an historic landmark. The fully instrumented vehicle was used for dynamic testing at Marshal during the Saturn's development.

It's ironic - the USSRC erected an expensive, full-sized Saturn V mockup near their museum several years ago, yet a genuine A.S. vehicle lay corroding in their Rocket Park, less than 200 yards away.....

JT

jamestox
2003-Apr-15, 03:31 PM
An "add-on" comment to my previous post:

Here's a photo showing the Saturn V's (http://aesp.nasa.okstate.edu/fieldguide/images/booster/ussrc/saturnv/DCP_0395.jpg) at the USSRC (courtesy of Jim Gerard's Field Guide to American Spacecraft (http://aesp.nasa.okstate.edu/fieldguide/pages/aaindex/home1.html)). The foreground shows the "business end" of the genuine vehicle, laying horizontally; in the background is the upright mockup.

JT

Glom
2003-Apr-15, 05:34 PM
SA-515 at JSC is definitely in need of a repainting as well.

jamestox
2003-Apr-20, 02:53 PM
Arm 9 (crew access to the CM aka "White Room") fully retracts at T-5 min, Arm 1 retracts at T-30 sec, and Arm 2 retracts at T-19 sec. The rest are in-flight retraction.

JT