They Didn't Ask Me (dr_phil_physics) wrote,
They Didn't Ask Me

Escape Velocity

So I managed to get out of the house today -- first time since I got home. It was a lovely day in the neighborhood, sunny with temps near fifty. And there was something I needed to do: Go see a movie.

Of course I did my prelab. The Holland 7 Theatre has a curb and three or four steps. But I was sure that it had to have a wheelchair ramp. I thought it was to the right of the entrance and sure enough, looking at the satellite view in Google Maps, I could clearly see the blue painted cutout in the sidewalk and the ramp behind the planters. I love living in the future.

After that it was just a matter of what equipment to take. Not being sure exactly how wide the doors are to the handicapped bathroom stalls, I ended up taking the walker and both canes. Still not graceful in getting in or out of the passenger seat of the Bravada, but it worked. I knew that my movement would be a little bit tighter with jeans instead of loose sweat shorts. But... the cuffs provided a handy grab point to get that recalcitrant left foot in. And I'm still weak on the stairs into the house, though I am figuring out how to do it better. And we will probably get someone in to change the three steep steps into four shallower ones.

And driving again some day. (grin)

So, off to the movies!

Gravity 3D [PG-13]
Holland 7 Theatre #1 1:10pm 2x$9.00

"Everybody" said we had to see this in 3D. Even people I know who hate 3D. I suppose we could've tried for IMAX 3D, but even with the walker, that's a long walk all the way to the back of the complex. That, and we really like the Holland 7 -- it's big enough but with a small town flavor. And speaking of flavor, they have the best popcorn in the area. (grin)

I was surprised when they started talking about this movie. Unexpected. Not going to any movies for over six months, I hadn't seen any trailers and no buzz. George Clooney and Sandra Bullock? Who let them into a spacesuit? Reminded me of Julia Roberts in Notting Hill, where she portrayed a blockbuster actress who stars in big space opera movies. But this is real casting and not light or farcical space opera.

Gravity is a tale of two NASA astronauts -- veteran Clooney and rookie specialist Bullock -- who are EVA when total disaster strikes. We witness the destruction of every space vehicle and space station we see in the film. It particularly hurt to see the Hubble Space Telescope reduced to rubble. We are now at the mercy of the Physics. Collisions, rotations, oxygen and fuel consumption rates, and orbital mechanics.

So how was the 3D you ask? Very effective and not annoying. Once Clooney reached out towards a bolt, but I was more impressed with the sharp clarity of details in the spacesuit glove than feeling it was a gratuitous gotcha. There are spectacular vista shots, unnerving rotating POV shots and long takes full of detail. Two shots come to mind for recognition. A zoom in to Sandra Bullock's face, coming through the helmet glass and turning so we can see the heads up display, then pulling out. The second involves swimming through the compartments of the ISS.

Though it is a bit selective, they pay far more than lip service to the reality that the vacuum of space is silent. That Sandra's character is a specialist just for this one particular mission and not a seasoned astronaut provides the basis of As You Know Bob dialogue directed for the audience's benefit, whether voiced by Clooney or by Sandra talking her way through procedures she never expected to have to do.

Should we be upset that they have a Space Shuttle Explorer in the near future? No. I suspect that even with the end of the Shuttle program, the Space Shuttle is the face of contemporary space travel to the public. Also, in the competing technologies of space transports, it's not inconceivable that a second generation Shuttle could be produced. Especially if one is planning one more Hubble Space Telescope upgrade mission.

Look, even Apollo 13, which was based on history, took some liberties while delivering the best zero-gee photography seen up to that time. Though flawed in a few spots, the motions in Gravity are terrifically realistic, and I've seen the real thing in IMAX Space Station 3D.

Among the scientific criticisms are some quite obvious to me. For example, it is so convenient to have the Hubble Space Telescope, the International Space Station and the Chinese space station all essentially in the same orbit. But not only are the orbital heights different, there are differences in angle to the equator. This was a key problem in Martin Caidin's Marooned. Wikipedia's article on the movie contains a nice graphic. Also, if you aren't close to an object in a similar orbit -- less than fifty meters -- then dead reckoning doesn't work. Aim directly at an object and fire thrusters in that direction once and you are guaranteed to miss. For one thing, boosting towards an object by increasing your speed will result in you going into a lower orbit. Celestial mechanics is something left to navigational computers for a reason.

Then there's the description that the debris which threatens everything is "moving at 50,000 mph" and will come around again in 90 minutes. While it is true that the orbital period in Low Earth Orbit (about 250 miles or 400 km above the Earth) is approximately 90 minutes, a calculation I frequently show in my Physics classes, the debris is traveling in a contra-orbit or it wouldn't be particularly threatening. So the return time is much less than 90 minutes, as our heroes go around the Earth one way and the debris goes the other way. Contra-orbits would be bad as the closing speed would be twice the orbital speed. But orbital speed in LEO is nearly 18,000 mph -- so twice that is only 36,000 mph. But very little debris should end up in a perfectly intersecting contra-orbit anyways. And if the debris was travelling at 50,000 mph, then that's about twice escape velocity from Earth, which means it ain't in orbit. So no jeopardy.

But what the hell, let them have an exciting story. In real life, a disaster like this would result in a fifteen second movie, which wouldn't be any fun at all. (double-trouble-grin)

What about The Problem? Russians or anyone taking out there own satellite? It's happened, I do believe, and NASA was not happy about that, though not as devastating as in the movie.

Finally, regarding having a rookie specialist handling a reentry, this isn't the case of a 19 year old Xbox aficionado taking over the controls of a 747 in the middle of a flight. First, she's had some Soyuz simulator time. Second, the Soviets and later the Russians have designed some very good automated flight systems. In real life, the one flight of the Soviet space shuttle Buran was unmanned and operated totally on the automatics. And given history, it is not absurd for the Chinese to produce a Soyuz copy.

Overall, my nits are NOT going to spoil the grandeur of this movie. It is a huge hit, with over half a billion dollars in box office so far. And this with only a cast of two and some voices. If it was only entertainment, it would be fine. If it inspires an American public to appreciate the space program again, that would be amazing.

Expect to see an Academy Award nomination for Sandra Bullock, IMHO.

HIGHLY Recommended

TRAILERS:Include the next Thor movie with another great part for Loki. The second Hobbit movie. And... nothing else comes to mind.

But I Got To Go To A Movie!

Dr. Phil

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