[meteorite-list] What Does A Real Astronaut Think Of 'Gravity'?

From: Matson, Robert D. <ROBERT.D.MATSON_at_meteoritecentral.com>
Date: Fri, 18 Oct 2013 11:23:11 -0700
Message-ID: <7C640E28081AEE4B952F008D1E913F17085FE839_at_0461-its-exmb04.us.saic.com>

Hi Paul,

I, too, loved the movie for all the reasons that Garrett Reisman gave
in the interview. For all the very difficult things that they got
right, I was a little surprised by some of the small things they
got terribly wrong -- which would have been trivial to get right.
Here are a few, some of which were mentioned by Garrett, a few
that were caught by Neil deGrasse Tyson (who, like me, loved all
the things the movie got right!), and some that are my own. SPOILER
ALERT for those that haven't seen Gravity and intend to do so!!
I've done my best to only mention enough about the flaws to identify
them. No need to discuss the plot, overall storyline or ending. But
if you're going to see the movie, stop reading now!!

Here we go:

1. As mentioned by Garrett, Sandra Bullock's inability to "hold on"
to Clooney in a particular scene. The only way this scene would
have made sense is if the end of the tether they were attached to
was rotating about the station (generating centripetal force).
But it wasn't.

2. Was a first-time astronaut medical doctor the best choice for
performing an EVA and doing a Hubble repair?

3. I'm not 100% sure of this next one (I would need to see the
movie again), but it appeared that all the satellite debris
was orbiting in the opposite direction of ISS -- i.e. east to
west. Given the country of origin of the debris, this would be
backwards.

4. Communication satellites would have been fine in GEO, though
I understand the plot need for a loss of communication with the
ground.

5. ISS and the Chinese Space Station are orbiting at different
inclinations (ISS at 51.65 degrees, Shenzhou at about 42.8 degrees),
so they are rarely anywhere near each other. When they are, they
have huge relative velocities, so there is no way to get from
one to the other.

6. Set aside #5 and allow for some "future" Chinese Space Station
that ~does~ happen to have a very similar orbit to ISS. If you
want to "fly" from one station to the other roughly 100 km away,
and you can only do a single propulsive burn to force the
intercept, the one thing you do NOT do is aim directly at your
target! Orbital mechanics is counterintuitive, and to perform
such a rendezvous maneuver would actually require you to aim
in the opposite direction -- and get the delta-V *exactly*
right.

7. If your space station has the misfortune of being in an orbit
that intersects the general orbit of an expanding cloud of debris,
you will not cross that debris cloud every 90 minutes -- you'll
cross it every 45 minutes. Of course, the pace of the movie was
already lightning fast, so having only 45-minutes between
episodes of terror may not have fit the timeline the writer
envisioned.

--Rob
Received on Fri 18 Oct 2013 02:23:11 PM PDT