why not send old satellites out into space?

Instead of deorbiting old satellites to crash into the earth, why don't
they send them out into space? The ocean shouldn't be used as a garbage
dump, whereas space is practically infinite.

wrote:
Instead of deorbiting old satellites to crash into the earth, why don't
they send them out into space? The ocean shouldn't be used as a garbage
dump, whereas space is practically infinite.

Because they do not come back intact, but burn up on reentry.
The amount of sinking shipping vastly, utterly dwarfs the small amount
of debris, perhaps tons a year, not hundreds of thousands.
And the rocket to boost it into space would weigh LOTS, and vastly
increase the cost of it.

wrote in
oups.com:

Instead of deorbiting old satellites to crash into the earth, why don't
they send them out into space? The ocean shouldn't be used as a garbage
dump, whereas space is practically infinite.

Which satellites are you referring to? Currently, geostationary satellites
*are* disposed by boosting them into higher orbits.

Satellites in low Earth orbit (LEO) are disposed by deorbiting because they
are deep in Earth's gravity well. Deorbiting them is much cheaper than
boosting them.
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Ian Stirling wrote:
Because they do not come back intact, but burn up on reentry.

Not all of it burns up during re-entry, right? From what I recall from
news articles that I've read, it usually just breaks up, but pieces
still hit the ocean. And sometimes the de-orbit goes awry, so that the
satellite does not break up enough, or it doesn't land in the intended
area. Isn't it just a matter of time before someone gets killed by a
deorbiting satellite?

And aren't there radioactive or other harmful substances on satellites?
That can't be good to be burning up in the atmosphere?

Jorge R. Frank wrote:
Which satellites are you referring to? Currently, geostationary
satellites
*are* disposed by boosting them into higher orbits.

thanks, I didn't know that.

Satellites in low Earth orbit (LEO) are disposed by deorbiting
because they
are deep in Earth's gravity well. Deorbiting them is much cheaper
than
boosting them.

I thought that when a satellite is in orbit, it is in perfect
equilibrium. If you nudge it slower, it will fall to the earth. If you
nudge it faster, it will escape orbit.

For the Hubble, they are saying that they will send a robotically
controlled liquid fueled engine to dock with the Hubble to deorbit it.
If you have to spend that much money to send a rocket to dock with the
Hubble, how much more would it cost to boost it into higher orbit?

wrote in message
oups.com...
Jorge R. Frank wrote:
Which satellites are you referring to? Currently, geostationary
satellites
*are* disposed by boosting them into higher orbits.

thanks, I didn't know that.

Satellites in low Earth orbit (LEO) are disposed by deorbiting
because they
are deep in Earth's gravity well. Deorbiting them is much cheaper
than
boosting them.

I thought that when a satellite is in orbit, it is in perfect
equilibrium. If you nudge it slower, it will fall to the earth. If you
nudge it faster, it will escape orbit.

The Earth's atmosphere doesn't end at a particular point. It stretches out
for thousands of miles and causes drag on satellites. This drag slowly
reduces the orbit causing the satellite to fall to Earth.

For the Hubble, they are saying that they will send a robotically
controlled liquid fueled engine to dock with the Hubble to deorbit it.
If you have to spend that much money to send a rocket to dock with the
Hubble, how much more would it cost to boost it into higher orbit?

Lots. Besides, a higher orbit is a delaying tactic, not a solution.
Someday we may have to do something to clean that graveyard orbit up. In
the case of Geostationary satellites it is currently more economic to boost
them that to deorbit them. For lower orbits, it's cheaper to deorbit them.
It's all based on what's cheapest and "good enough for now".

Space may be near infinite, but to get to that infinity would require solar
escape velocity, and possibly galactic escape velocity. That would be very
expensive. Besides, considering we may be occupying that Space someday it's
irresponsible to just keep throwing junk out there. Best dispose of it
where you know it will stay and not coming raining down on your head at some
future point.

uray

wrote:
Not all of it burns up during re-entry, right? From what I recall
from
news articles that I've read, it usually just breaks up, but pieces
still hit the ocean.

Anything coming back from space without the benefit of a heat shield
will be exposed to temperatures in excess of 1000 degrees C for about
15 minutes. This will vapourise any rubber, plastics or remaining
fuel. Aluminum will melt, and larger items will be torn apart by the
10G reentry forces. What makes it to the ground is often falling at
very slow speeds. The one recorded instance of someone being hit by
reentry debris was hit in the neck by a piece of wire mesh; she wasn't
injured.

And sometimes the de-orbit goes awry, so that the
satellite does not break up enough, or it doesn't land in the
intended
area. Isn't it just a matter of time before someone gets killed by a
deorbiting satellite?

I have never once heard of a planned de-orbit that went awry and landed
outside the target area (I'm not counting things with heat shields that
are designed to survive like Columbia STS-107 or Soyuz TMA-1). The
Pacific is a very big target, and is difficult to miss. There have
been cases (mostly in the 70's) when large items fell back in an
uncontrolled manner because nobody was planning for their deorbit when
they were launched. But everyone is a lot more careful these days. In
fact NASA is paranoid about it -- they're launching a 'burial' mission
(probably robotic) to Hubble specifically so that they can de-orbit it
in a planned way.

And aren't there radioactive or other harmful substances on
satellites?
That can't be good to be burning up in the atmosphere?

The Soviet Union liked to launch nuclear powered spy satellites. But
that practice was stopped a long time ago. For the most part, a
satellite is just a computer like the one on your desk, but inside an
aluminum case instead of a steel case.

The danger of airplanes falling out of the sky is far far greater than
deorbiting satellites (both planned and unplanned). Countless people
get killed by falling planes. Nobody has ever been hurt by a falling
satellite.

wrote in message
oups.com...
Jorge R. Frank wrote:
Which satellites are you referring to? Currently, geostationary
satellites
*are* disposed by boosting them into higher orbits.

thanks, I didn't know that.

Satellites in low Earth orbit (LEO) are disposed by deorbiting
because they
are deep in Earth's gravity well. Deorbiting them is much cheaper
than
boosting them.

I thought that when a satellite is in orbit, it is in perfect
equilibrium. If you nudge it slower, it will fall to the earth. If you
nudge it faster, it will escape orbit.

Nope, it simply goes into a slightly higher orbit. (technically if you
nudge at one point, the opposite point gets higher, etc.)

If you have a perfectly smooth airless sphere the size of the Earth, you
could orbit 5' above it or 5 million miles above it, simply at different
velocities.

wrote in message
oups.com...
Ian Stirling wrote:

And aren't there radioactive or other harmful substances on satellites?
That can't be good to be burning up in the atmosphere?

Very few if any carry radioactive substances. (In the past a few used RTGs
which contained Pu-238, but now that's only used for deep space missions.)

Others carry fuel, but that's pretty much exhausted upon re-entry.

Just as you say space is infinite, in cases like this, the ratio of the mass
of the atmosphere to that of the satellite is pretty close to infinite for
practical purposes.

On 2 Apr 2005 13:38:41 -0800, in a place far, far away,
made the phosphor on my monitor glow in such a
way as to indicate that:

Ian Stirling wrote:
Because they do not come back intact, but burn up on reentry.

Not all of it burns up during re-entry, right? From what I recall from
news articles that I've read, it usually just breaks up, but pieces
still hit the ocean. And sometimes the de-orbit goes awry, so that the
satellite does not break up enough, or it doesn't land in the intended
area. Isn't it just a matter of time before someone gets killed by a
deorbiting satellite?

If by "matter of time" you mean thousands of years, perhaps...

And aren't there radioactive or other harmful substances on satellites?

Not generally.

That can't be good to be burning up in the atmosphere?

You have an extremely overinflated notion of how many satellites we
have.