History Channel
Season. 3 Episode. 11
http://www.history.com/shows/the-universe
http://en.wikipedia.org/wiki/The_Universe_%28TV_series%29
EXCERPTS:
EDGE OF SPACE
(Edge of Earth/ Atmospheres)
SPACE DIVING
"the zone of space that surrounds Earth
and begins 120 miles above sea level.
In the first two minutes of the jump
the space diver will reach speeds of 2,500 miler per hour.
while in free fall.
Atmospheric drag will heat the spacesuit
to 474 degrees F.
SPACE SUIT
"To protect the body, spacesuits are designed in layers.
"Comfortable is a relative term.
So if you're comfortable on a camping trip
then you'll be fine on the space station.
I can't tell you when it will be $4,000,
If it doesn't start off at $40 million.Earth orbit, our edge of space,
is generally divided into three parts.
Low Earth orbit is a 1100 mile wide belt
that is closest to Earth's atmosphere
and begins only 120 miles above sea level.
... Most of the manned space proggram takes place in that radius.
Low Earth orbit is likea busy city, lots of activity (by satellites)
... orbit the Earth in 90 minutes.
Above low Earth orbit is a region called Meduim Earth orbit.
This wide stretch of space is 1200 to 14000 miles above Earth.
Many communication satellites are launched into orbit here.
GPS satellites roughly orbit the Earth at about 12000 miles.
They orbit the Earth twice per day.
Medium Earth orbit is also home
to the treacherous Van Allen radiation belts
These belts of high-energy charged particles
can send a $300 million satellite spiraling out of control
or give a human being a fatal dose of radiation.
High Earth orbit, or geo-synchronous orbit
if low Earth orbit is a busy city,
high Earth orbit is rural farmland.
22,000 to 35,000 miles above sea level.
Here, over 2000 satellites call high Earth orbit home.
They orbit around the Earth every 24 hours.
To reach the target
a spacecraft must travel 17,500 miles per hour.
Even one degree of and spacecraft will end up in the wrong orbit.
In theory, objects can stay in orbit forever
as long as they have enough speed
to resist the pul of Earth's gravity.
You just keep falling around the world over and over again.
In October 2007, the US Navy shot down
an out of service satellite with a cruice missile
before it reentered the atmosphere.
The reason?
The satellite carried hazardous material onboard
and had it crashed to the ground,
could have poisoned thousands.
... The operation was called "Burnt Frost."
From the first launch of Sputnik in 1957
debris (space junk) has steadily been
accumulating around planet Earth.
It looks like the Earth is surrounded by a hive of bees.
these pieces are traveling upwards of 22,000 miles per hour.
Say, more than ten times faster then a bullet.
In 2007, the total estimated amount of space debris
was 20,000 pieces,
14,000 of which were trackable.
Then in 2008
China's space program
intentionally crashed two satellites together as an anti-satellite test.
The international space community was outraged.
By th 10th Jan 2007, the number of objects we were tracking
was less than 14,000.
Here we are 16 months later
and we've increased that number by over 30% to over 18,000.
Back in 1997, we had a 570-pound stainless steel tank
that landed about 50 yards from a farmer's house in Texas.
He was not particularly pleased byu that.
There was a re-entry that came into Cape Town in SA.
3/4 of the Earth's surface is water
so a lot of it lands in the water.
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