TWO SATELLITES COLLIDE IN ORBIT

In article ,
_ wrote:
On Thu, 12 Feb 2009 18:04:29 -0000, OG wrote:

"_" wrote in message
...
On Wed, 11 Feb 2009 21:50:11 GMT, Sam Wormley wrote:

TWO SATELLITES COLLIDE IN ORBIT
-------------------------------
In an unprecedented space collision, a commercial Iridium communications
satellite and a presumably defunct Russian Cosmos satellite ran into each
other Tuesday above northern Siberia, creating a cloud of wreckage,
officials said today.

http://spaceflightnow.com/news/n0902/11iridium/

Any care to guess (or state, if known) what the relative impact speed was?

Guesstimation
Reports indicate they are at an orbital height of about 790km which gives an
orbital speed of about 26,000 km/hour, and their orbits were not far off
right angles at collision, so their relative impact speed was about
36-40,000 km/h (10km/s)

If so, wow.

Assuming the Iridium was about 500kg, that's 250*(40,000,000^2) = 4x10^17
joules of KE.

Perhaps it's a good thing they were not head-on.

They couldn't be head-on, since we almost never launch satellites
in retrogade orbits. However at right angles isn't that much less
than head-on as seen from an energy point of view.




--
----------------------------------------------------------------
Paul Schlyter, Grev Turegatan 40, SE-114 38 Stockholm, SWEDEN
e-mail: pausch at stjarnhimlen dot se
WWW: http://stjarnhimlen.se/

On Fri, 13 Feb 2009 10:43:42 GMT, Paul Schlyter wrote:

In article ,
_ wrote:
On Thu, 12 Feb 2009 18:04:29 -0000, OG wrote:

"_" wrote in message
...
On Wed, 11 Feb 2009 21:50:11 GMT, Sam Wormley wrote:

TWO SATELLITES COLLIDE IN ORBIT
-------------------------------
In an unprecedented space collision, a commercial Iridium communications
satellite and a presumably defunct Russian Cosmos satellite ran into each
other Tuesday above northern Siberia, creating a cloud of wreckage,
officials said today.

http://spaceflightnow.com/news/n0902/11iridium/

Any care to guess (or state, if known) what the relative impact speed was?

Guesstimation
Reports indicate they are at an orbital height of about 790km which gives an
orbital speed of about 26,000 km/hour, and their orbits were not far off
right angles at collision, so their relative impact speed was about
36-40,000 km/h (10km/s)

If so, wow.

Assuming the Iridium was about 500kg, that's 250*(40,000,000^2) = 4x10^17
joules of KE.

Perhaps it's a good thing they were not head-on.

They couldn't be head-on, since we almost never launch satellites
in retrogade orbits. However at right angles isn't that much less
than head-on as seen from an energy point of view.

Head on means (assuming equal masses) all the KE is converted - so I'd say
that yes, there is a biggish difference.

But anyway, I found this page (a good long read):

http://blogs.discovermagazine.com/ba...-a-correction/

"Paul Schlyter" wrote in message
...
In article ,
_ wrote:
On Thu, 12 Feb 2009 18:04:29 -0000, OG wrote:

"_" wrote in message
...
On Wed, 11 Feb 2009 21:50:11 GMT, Sam Wormley wrote:

TWO SATELLITES COLLIDE IN ORBIT
-------------------------------
In an unprecedented space collision, a commercial Iridium
communications
satellite and a presumably defunct Russian Cosmos satellite ran into
each
other Tuesday above northern Siberia, creating a cloud of wreckage,
officials said today.

http://spaceflightnow.com/news/n0902/11iridium/

Any care to guess (or state, if known) what the relative impact speed
was?

Guesstimation
Reports indicate they are at an orbital height of about 790km which
gives an
orbital speed of about 26,000 km/hour, and their orbits were not far off
right angles at collision, so their relative impact speed was about
36-40,000 km/h (10km/s)

If so, wow.

Assuming the Iridium was about 500kg, that's 250*(40,000,000^2) = 4x10^17
joules of KE.

Perhaps it's a good thing they were not head-on.

They couldn't be head-on, since we almost never launch satellites
in retrogade orbits. However at right angles isn't that much less
than head-on as seen from an energy point of view.


Since one (Iridium) was in a near polar orbit, having another in the counter
polar orbit /could/ result in a near head-on impact without having to have
either in a retrograde orbit.

Paul Schlyter wrote:
They couldn't be head-on, since we almost never launch satellites
in retrogade orbits.

Polar orbit.

Just because your launch puts your bird going north means a launch on the other
side of the planet puts their bird going south.

On Feb 13, 4:09 am, "OG" wrote:
"Paul Schlyter" wrote in message

...



In article ,
_ wrote:
On Thu, 12 Feb 2009 18:04:29 -0000, OG wrote:

"_" wrote in message
. ..
On Wed, 11 Feb 2009 21:50:11 GMT, Sam Wormley wrote:

TWO SATELLITES COLLIDE IN ORBIT
-------------------------------
In an unprecedented space collision, a commercial Iridium
communications
satellite and a presumably defunct Russian Cosmos satellite ran into
each
other Tuesday above northern Siberia, creating a cloud of wreckage,
officials said today.

http://spaceflightnow.com/news/n0902/11iridium/

Any care to guess (or state, if known) what the relative impact speed
was?

Guesstimation
Reports indicate they are at an orbital height of about 790km which
gives an
orbital speed of about 26,000 km/hour, and their orbits were not far off
right angles at collision, so their relative impact speed was about
36-40,000 km/h (10km/s)

If so, wow.

Assuming the Iridium was about 500kg, that's 250*(40,000,000^2) = 4x10^17
joules of KE.

Perhaps it's a good thing they were not head-on.

They couldn't be head-on, since we almost never launch satellites
in retrogade orbits. However at right angles isn't that much less
than head-on as seen from an energy point of view.

Since one (Iridium) was in a near polar orbit, having another in the counter
polar orbit /could/ result in a near head-on impact without having to have
either in a retrograde orbit.

Hi
To make it clearer, if I launch a polar orbit at the same time as a
previously
launched was going south ( which it has to do every orbit ) I will
have the two
going head on. I don't even have to launch in opposite directionsNorth
and
South, just launch at different times.
Dwight

wrote in message
...
On Feb 13, 4:09 am, "OG" wrote:
"Paul Schlyter" wrote in message

...



In article ,
_ wrote:
On Thu, 12 Feb 2009 18:04:29 -0000, OG wrote:

"_" wrote in message
. ..
On Wed, 11 Feb 2009 21:50:11 GMT, Sam Wormley wrote:

TWO SATELLITES COLLIDE IN ORBIT
-------------------------------
In an unprecedented space collision, a commercial Iridium
communications
satellite and a presumably defunct Russian Cosmos satellite ran
into
each
other Tuesday above northern Siberia, creating a cloud of wreckage,
officials said today.

http://spaceflightnow.com/news/n0902/11iridium/

Any care to guess (or state, if known) what the relative impact
speed
was?

Guesstimation
Reports indicate they are at an orbital height of about 790km which
gives an
orbital speed of about 26,000 km/hour, and their orbits were not far
off
right angles at collision, so their relative impact speed was about
36-40,000 km/h (10km/s)

If so, wow.

Assuming the Iridium was about 500kg, that's 250*(40,000,000^2) =
4x10^17
joules of KE.

Perhaps it's a good thing they were not head-on.

They couldn't be head-on, since we almost never launch satellites
in retrogade orbits. However at right angles isn't that much less
than head-on as seen from an energy point of view.

Since one (Iridium) was in a near polar orbit, having another in the
counter
polar orbit /could/ result in a near head-on impact without having to
have
either in a retrograde orbit.

Hi
To make it clearer, if I launch a polar orbit at the same time as a
previously
launched was going south ( which it has to do every orbit ) I will
have the two
going head on. I don't even have to launch in opposite directionsNorth
and
South, just launch at different times.

Really?