ISS till 2028?

On 3/13/2010 11:55 AM, Brian Thorn wrote:

Post-2020, replace the solar panels with solar dynamics for more
power/less drag/reduced need for batteries?


They looked into the reflector/heat engine ones at the beginning of the
ISS program (in fact clean back when they were working on Space Station
Freedom), but decided the solar cell arrays were a better choice.
One problem I can see for the reflector type is degradation of the
reflecting surface due to atomic oxygen, UV exposure, and radiation.
The mirrored thermal blankets on Hubble deteriorated badly between the
launch and the first maintenance visit, and a lot of the test materials
on the exterior of the the Long Duration Exposure Facility had
completely vanished by the time it was finally recovered after the
grounding due to the loss of Challenger.

Pat

wrote:
Has anyone run the numbers as to the likelyhood of a killer debris
impact, as the iSS life gets extended?


No, we were leaving that fear-mongering to you.


Espically since LEO is now cluttered with garbage, some from
intentially destroyed satellite killers.....

--
Greg Moore
Ask me about lily, an RPI based CMC.

"Pat Flannery" skrev i meddelelsen
dakotatelephone...

"With regard to the International Space Station, the above article also
points that the ISS "has armor to protect it against stuff as much as
an inch across." So it sounds like the risk to the ISS is pretty
close to zero since meteors are usually much less than an inch across."

I seriously doubt that the ISS is capable of sustaining a hit by a piece
of rock an inch in diameter,

[...]

Maybe someone originally opined or calculated that the ISS can survive a
fleck of paint as much as an inch across, or that an inch-size rock striking
a pressurized module would leave a pair of holes small enough for the rest
of the complex to survive, and the distinction was lost during serial
retelling. :-)

Jon Lennart Beck.

On 3/13/2010 7:37 PM, Greg D. Moore (Strider) wrote:

No, we were leaving that fear-mongering to you.

Sooner or later, something is bound to hit something that's manned in
orbit with enough force to punch a hole in it, as there have been lots
of space impacts of smaller sizes on stations and shuttles already.
Although we can maneuver the ISS out of the way of debris we can track,
or known small debris clouds in orbit, the same can't be said for
incoming meteors, and one of those was thought to be the cause of a
satellite loss already:
http://answers.google.com/answers/th...id/110401.html

"With regard to the International Space Station, the above article also
points that the ISS "has armor to protect it against stuff as much as
an inch across." So it sounds like the risk to the ISS is pretty
close to zero since meteors are usually much less than an inch across."

I seriously doubt that the ISS is capable of sustaining a hit by a piece
of rock an inch in diameter, as that would be equivalent to hitting it
with a 25mm cannon round going at over 11,000 meters per second.
A Bradley IFV is armed with a 25 mm cannon firing rounds that have a
muzzle velocity of 1,100 meters per second, and those have destroyed
T-72 tanks.
So unless the crew modules of the ISS are covered in several inches
worth of armor plate, a fairly small meteor hit is going to blow a hole
in them.

Pat

On 3/14/2010 3:52 AM, Raven wrote:

Maybe someone originally opined or calculated that the ISS can survive a
fleck of paint as much as an inch across, or that an inch-size rock
striking a pressurized module would leave a pair of holes small enough
for the rest of the complex to survive, and the distinction was lost
during serial retelling. :-)

It would be fun to figure out how much total energy would be released in
a impact like that, assuming the impactor was rock or nickel-iron.
I got my little tektite off the shelf, and that's about an inch in size,
and weighs in at 1/4 ounce, or 110 grains.
Using this bullet impact energy calculator:
http://www.firearmexpertwitness.com/...s/calcnrg.html and
converting the 11,000 meters per second velocity into 36,080 feet per
second, we end up with a impact force of 317,891.67 foot-pounds.
Ouch.
The small ones that have hit satellites were converted into plasma by
the heat released on impact. The effect internally on the ISS would be
like having a hand grenade going off in the room, due to the severe
shockwave generated by the hypersonic plasma and vaporized metal being
blown out of the impact hole.

Pat

In message tatelephone
Pat Flannery wrote:

"With regard to the International Space Station, the above article also
points that the ISS "has armor to protect it against stuff as much as
an inch across." So it sounds like the risk to the ISS is pretty
close to zero since meteors are usually much less than an inch across."

I seriously doubt that the ISS is capable of sustaining a hit by a piece
of rock an inch in diameter, as that would be equivalent to hitting it
with a 25mm cannon round going at over 11,000 meters per second.
A Bradley IFV is armed with a 25 mm cannon firing rounds that have a
muzzle velocity of 1,100 meters per second, and those have destroyed
T-72 tanks.
So unless the crew modules of the ISS are covered in several inches
worth of armor plate, a fairly small meteor hit is going to blow a hole
in them.

You might well find that it's the lower velocity impacts would cause
most trouble. The high velocity stuff is mostly going to vapourise as it
hits the outer shell of a module and disperse most of the energy in the
insulation before anything reaches the pressure hull, and what does get
through will be spread over a much larger area.

Anthony

Raven wrote:
"Pat Flannery" skrev i meddelelsen
dakotatelephone...

"With regard to the International Space Station, the above article also
points that the ISS "has armor to protect it against stuff as much as
an inch across." So it sounds like the risk to the ISS is pretty
close to zero since meteors are usually much less than an inch across."

I seriously doubt that the ISS is capable of sustaining a hit by a piece
of rock an inch in diameter,

[...]

Maybe someone originally opined or calculated that the ISS can survive
a fleck of paint as much as an inch across, or that an inch-size rock
striking a pressurized module would leave a pair of holes small enough
for the rest of the complex to survive, and the distinction was lost
during serial retelling. :-)

Nah, more likely someone confused units. The real limit is 1 cm, not 1 inch.

Anthony Frost wrote:
In message


You might well find that it's the lower velocity impacts would cause
most trouble. The high velocity stuff is mostly going to vapourise as
it hits the outer shell of a module and disperse most of the energy
in the insulation before anything reaches the pressure hull, and what
does get through will be spread over a much larger area.

Keep in mind too that "outer shell" is a Whipple shield which will
dissappate a lot of the damage.

while trying to remember if it was Whipple or something else, I came across:
http://orbitaldebris.jsc.nasa.gov/pr...shielding.html


Anthony

--
Greg Moore
Ask me about lily, an RPI based CMC.

On 3/14/2010 9:48 AM, Jorge R. Frank wrote:

Maybe someone originally opined or calculated that the ISS can survive
a fleck of paint as much as an inch across, or that an inch-size rock
striking a pressurized module would leave a pair of holes small enough
for the rest of the complex to survive, and the distinction was lost
during serial retelling. :-)

Nah, more likely someone confused units. The real limit is 1 cm, not 1
inch.

Even that is going to make one hell of a bang when it hits, if it's
something falling into Earth's gravity well rather than something in orbit.
The one thing you wouldn't want to hit in orbit is part of one of the
Israeli satellites that are launched into retrograde orbits, so your
impact speed could be up to around 36,000 mph.

Pat

On 3/14/2010 10:03 AM, Greg D. Moore (Strider) wrote:

You might well find that it's the lower velocity impacts would cause
most trouble. The high velocity stuff is mostly going to vapourise as
it hits the outer shell of a module and disperse most of the energy
in the insulation before anything reaches the pressure hull, and what
does get through will be spread over a much larger area.

Keep in mind too that "outer shell" is a Whipple shield which will
dissappate a lot of the damage.

while trying to remember if it was Whipple or something else, I came across:
http://orbitaldebris.jsc.nasa.gov/pr...shielding.html

Good article, I stuck that one in my favorites folder.
The concept reminds me somewhat of the Chobham armor used on modern tanks.

Pat