Six NASA ISS Science Officer Don Pettit answered these questions
William McCauley, Starks, La., Age: 8
How long does it take you to train to be an astronaut? Do I have
to be good in math to be an astronaut? When you train, do you go
into a room that has no gravity? Thank you for your time.
It takes several years of training to be an astronaut after you
have your college degree. You should be good in science and math
and know how machines work since your spacecraft is nothing but
a big machine.
Renee Dixon, Tyler, Texas, Age: 50
While watching your experiments with the water
film and the formation of droplets, it occurred to me how slowly
they moved, as well as other movements I have seen of crewmembers
doing various tasks. Does zero-g have any effect on the speed of
Weightlessness itself does not affect your
ability to move fast. You can move fast if you want too. It is easy
to move too fast, and then, you lose control over your body or what
you are working with so experienced astronauts tend to do everything
slowly. To accomplish a task, slow is quicker than fast.
Jeffrey Vasquez, Phoenix, Ariz.,
Why does the ISS not twinkle like a star during
transits, and why is it possible to see it one week, then not the
next with the same coordinates?
Stars twinkle from changes with time in the
atmosphere’s optical properties (refractive index) as you view the
star at one point in the sky. Since the station is constantly moving,
you do not notice that it is twinkling. As ISS orbits the Earth,
the path precesses in time so that in about two weeks, you can no
longer see it but in about another two weeks, you can.
Justin Uhde, Thornton, Calif., Age: 12
What is it like to be able float and not have
to use your feet to walk? Does it feel like you're swimming with
It feels like how you fly in your dreams.
Ralph Kings, Birmingham, U.K.,
I have seen lots of pictures taken while in space, and would like
to know if the current space station crew uses film cameras or digital
cameras? If film, does the crew experience any problems changing
film in the cameras? If digital, how are they sent back to Earth?
We use a mix of film and digital cameras. Changing film is no problem
in space. We downlink our digital images everyday. You can find
many of them on NASA web sites for Expedition 6.
Hayley Morris, Landsborough, Australia,
Was it hard to endure the training? Did you ever just want to stop?
If so, what made you keep going?
Training for space flight is enjoyable and only second to actually
Michael Wittlin, Oxnard, Calif.,
I'm teaching third grade at Rio Real in El Rio, Calif. What would
you say to a child about having a dream or goal in life?
I believe you need to follow what
is in your heart. However, one can have many dreams, and you must
be able to decide which ones are best to pursue and which are best
to remain as dreams.
Kodi Goodwin, Deer Park, Texas,
How does a plant respond to a low-gravity field such as in a spacecraft?
They grow just fine. However, providing the necessary
soil, humidity, light and heat can be a problem and requires rather
Ingrid Ludwig, Sydney, Australia,
Don Pettit: What is it with the drill? At least it looks like a
drill. We've noticed it on your camera setup, and again, there is
a photograph of you with drill in hand. Is there anything special
is used to drive a screw that moved the camera mount and compensates
for the orbital motion. This way time exposures at night can be
Cliff Fenton, Thibodaux, La.,
When doing astrophotography, you mentioned the lens length and aperture.
Could you tell me what the exposure time was, and what the digital
equivalent film speed was that you selected. Thanks!
ISO1600 with exposures up to 30 seconds.