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From:
William Wheeler, Marietta, Ga., Age: 21
To: Mission Specialist Franklin Chang-Díaz
Question:
As a mechanic here on Earth, I find it hard enough
to pull off some repairs. Did you find that having the added burden
of the EMU and weightlessness made it harder or easier to accomplish
the repairs to Canadarm2?
Chang-Díaz:
I guess the
answer comes in two parts. It is a yes and a no. In fact, I am
a bit of a mechanic myself, and I tend to compare this repair
to changing a transmission in your car. The advantage of being
in space, of course, is that weight is not really a factor. As
long as you move things slowly, it is very easy to maneuver large
objects -- a transmission, for example -- and in our case, the
actual joint of the Canadarm2, which weighs about 150 to 200 pounds.
So, in that sense it was easier to do it. However, the EMU itself,
it is a stiff suit, and moving around in it is difficult in some
ways. You also have to remember that everything you take out has
to be tethered, lest it will fly away. So you have to make sure
that every little bolt, every little component that you take out
from your repair site has to have a tether to someplace on the
structure - either to you or to the rest of the station. Otherwise,
you'll lose it. So, in many ways, the repairs are more difficult,
but also they are easier. So it has a two-part answer to the question.
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From:
Joshua Wilson, Dixons Mills, Ala., Age: 18
To: Mission Specialist Franklin Chang-Díaz
Question:
How long or what is the limit that an astronaut can
stay on an EVA without returning to the shuttle?
Chang-Díaz:
Actually, the
short answer is on the order of seven to eight hours or so. And
it is not a high limit in the sense that sometime EVAs can be
a little longer and sometimes they are shorter. But for the most
part, the suit can support the astronaut well on the order of
eight hours or so. After that time, you tend to run out of electrical
power and also oxygen in your suit. You can always go back to
the to the airlock, and without having to take the hood off, you
can replenish your oxygen. You can also do other things. Generally,
our EVAs are not any longer than seven hours or so.
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From:
Jessica, Salt Lake City, Utah, Age: 10
To: Mission Specialist Franklin Chang-Díaz
Question:
Can you see the forest fires on the Earth?
Chang-Díaz:
And
the answer is definitely yes, very much so. We see fires all over
the planet, not just certain areas, but they are spread all over
the planet. In some areas at certain times of the year, these
fires are actually human-induced in order to clear the fields
for planting crops in the following season. This has very bad
effects on our atmosphere because all the smoke and pollutants
that are raised into the atmosphere end up covering the entire
planet and begin to change the environmental conditions in which
we live. And, of course, all of those particulates and smoke in
the regions tend to induce a greater degree of illnesses -- respiratory
type illnesses -- in the people who live in those areas. So, fires
on the surface of the planet are not good, and we can definitely
see them.
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