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Russia Launches Long-Delayed Deep Space Radio Telescope



 
 
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  #1  
Old July 19th 11, 12:36 AM posted to sci.astro,sci.physics
Yousuf Khan[_2_]
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Posts: 1,692
Default Russia Launches Long-Delayed Deep Space Radio Telescope

Russia Launches Long-Delayed Deep Space Radio Telescope | Giant Space
Telescopes | Radio Astronomy & Deep Space Exploration | Space.com
http://www.space.com/12329-russia-la...telescope.html

  #2  
Old July 19th 11, 01:50 AM posted to sci.astro,sci.physics
eric gisse
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Posts: 303
Default Russia Launches Long-Delayed Deep Space Radio Telescope

Yousuf Khan wrote in
:

Russia Launches Long-Delayed Deep Space Radio Telescope | Giant Space
Telescopes | Radio Astronomy & Deep Space Exploration | Space.com
http://www.space.com/12329-russia-la...nt-radio-teles
cope.html



207,000 miles to 621 miles is a bit of an orbital swing.

I've never heard of this. This is neat.
  #3  
Old July 19th 11, 03:43 AM posted to sci.astro,sci.physics
Yousuf Khan[_2_]
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Posts: 1,692
Default Russia Launches Long-Delayed Deep Space Radio Telescope

On 18/07/2011 8:50 PM, eric gisse wrote:
Yousuf wrote in
:

Russia Launches Long-Delayed Deep Space Radio Telescope | Giant Space
Telescopes | Radio Astronomy& Deep Space Exploration | Space.com
http://www.space.com/12329-russia-la...nt-radio-teles
cope.html



207,000 miles to 621 miles is a bit of an orbital swing.

I've never heard of this. This is neat.


I'm not even sure why they are doing such an elliptical orbit like that?
Any advantages for viewing angles or stuff like that?

Yousuf Khan
  #4  
Old July 19th 11, 04:39 AM posted to sci.astro,sci.physics
eric gisse
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Posts: 303
Default Russia Launches Long-Delayed Deep Space Radio Telescope

Yousuf Khan wrote in
:

On 18/07/2011 8:50 PM, eric gisse wrote:
Yousuf wrote in
:

Russia Launches Long-Delayed Deep Space Radio Telescope | Giant

Space
Telescopes | Radio Astronomy& Deep Space Exploration | Space.com
http://www.space.com/12329-russia-la...e-giant-radio-

teles
cope.html



207,000 miles to 621 miles is a bit of an orbital swing.

I've never heard of this. This is neat.


I'm not even sure why they are doing such an elliptical orbit like

that?
Any advantages for viewing angles or stuff like that?

Yousuf Khan


No ****ing idea.

The distance isn't enough to alter the view seen, but it _might_ be
enough to play VLBI games but I don't believe the orbital information
and transmission setup is precise enough to preserve phase/timing
information down to the nanosecond.

Orbits are not accidental so either they wanted it to be there, or a
higher purpose was served that has putting it there as a byproduct. I
just can't figure it out.

  #5  
Old July 19th 11, 05:17 AM posted to sci.astro,sci.physics
Yousuf Khan[_2_]
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Posts: 1,692
Default Russia Launches Long-Delayed Deep Space Radio Telescope

On 18/07/2011 11:39 PM, eric gisse wrote:
Yousuf wrote in
I'm not even sure why they are doing such an elliptical orbit like

that?
Any advantages for viewing angles or stuff like that?

Yousuf Khan


No ****ing idea.

The distance isn't enough to alter the view seen, but it _might_ be
enough to play VLBI games but I don't believe the orbital information
and transmission setup is precise enough to preserve phase/timing
information down to the nanosecond.


I was thinking maybe the orbit would allow it to avoid the day side of
the planet and avoid being blocked by the planet as it looks at distant
stars. Also avoid it'll the radio noise of the planet. Earth is
supposedly much brighter than the Sun when it comes to radio.

Orbits are not accidental so either they wanted it to be there, or a
higher purpose was served that has putting it there as a byproduct. I
just can't figure it out.


Maybe they don't have a strong enough booster to put it in a circular
orbit that far up? That's almost as far as the Moon.

Yousuf Khan
  #6  
Old July 19th 11, 08:19 AM posted to sci.astro,sci.physics
Martin Brown
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Posts: 1,707
Default Russia Launches Long-Delayed Deep Space Radio Telescope

On 19/07/2011 03:43, Yousuf Khan wrote:
On 18/07/2011 8:50 PM, eric gisse wrote:
Yousuf wrote in
:

Russia Launches Long-Delayed Deep Space Radio Telescope | Giant Space
Telescopes | Radio Astronomy& Deep Space Exploration | Space.com
http://www.space.com/12329-russia-la...nt-radio-teles
cope.html



207,000 miles to 621 miles is a bit of an orbital swing.

I've never heard of this. This is neat.


I'm not even sure why they are doing such an elliptical orbit like that?
Any advantages for viewing angles or stuff like that?


Allows it to cover a decent range of baselines relative to ground based
scopes when operated as an interferometer (assuming that their orbit
determination is precise enough to get the correlators to lock-in).

The ground based VLBI network is stuck with the pattern formed by where
the various big steerable dishes happen to have been built.

Regards,
Martin Brown
  #7  
Old July 19th 11, 08:41 AM posted to sci.astro,sci.physics
Mike Dworetsky
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Posts: 715
Default Russia Launches Long-Delayed Deep Space Radio Telescope

Yousuf Khan wrote:
On 18/07/2011 11:39 PM, eric gisse wrote:
Yousuf wrote in
I'm not even sure why they are doing such an elliptical orbit like
that? Any advantages for viewing angles or stuff like that?

Yousuf Khan


No ****ing idea.

The distance isn't enough to alter the view seen, but it _might_ be
enough to play VLBI games but I don't believe the orbital information
and transmission setup is precise enough to preserve phase/timing
information down to the nanosecond.


I was thinking maybe the orbit would allow it to avoid the day side of
the planet and avoid being blocked by the planet as it looks at
distant stars. Also avoid it'll the radio noise of the planet. Earth
is supposedly much brighter than the Sun when it comes to radio.

Orbits are not accidental so either they wanted it to be there, or a
higher purpose was served that has putting it there as a byproduct. I
just can't figure it out.


Maybe they don't have a strong enough booster to put it in a circular
orbit that far up? That's almost as far as the Moon.

Yousuf Khan


It always helps to read the articles about which you post links. It is
stated that the orbit is designed to allow the telescope to work with the
interferometric network of radio telescopes on Earth to provided higher
resolution than can be obttained from the ground. From this I assume that
the ground stations can track the position of the telescope accurately
enough to permit good interferometry to be done.

A high-eccentricity orbit costs less than a low-eccentricity distant orbit
in terms of thrust required, yet it allows the radio telescope to be at a
large distance from Earth about 80-90% of the time (near apogee) in accord
with Kepler's 2nd law of planetary motion.

--
Mike Dworetsky

(Remove pants sp*mbl*ck to reply)

  #8  
Old July 19th 11, 10:55 PM posted to sci.astro,sci.physics
eric gisse
external usenet poster
 
Posts: 303
Default Russia Launches Long-Delayed Deep Space Radio Telescope

"Mike Dworetsky" wrote in
:

Yousuf Khan wrote:
On 18/07/2011 11:39 PM, eric gisse wrote:
Yousuf wrote in
I'm not even sure why they are doing such an elliptical orbit like
that? Any advantages for viewing angles or stuff like that?

Yousuf Khan


No ****ing idea.

The distance isn't enough to alter the view seen, but it _might_ be
enough to play VLBI games but I don't believe the orbital
information and transmission setup is precise enough to preserve
phase/timing information down to the nanosecond.


I was thinking maybe the orbit would allow it to avoid the day side
of the planet and avoid being blocked by the planet as it looks at
distant stars. Also avoid it'll the radio noise of the planet. Earth
is supposedly much brighter than the Sun when it comes to radio.

Orbits are not accidental so either they wanted it to be there, or a
higher purpose was served that has putting it there as a byproduct.
I just can't figure it out.


Maybe they don't have a strong enough booster to put it in a circular
orbit that far up? That's almost as far as the Moon.

Yousuf Khan


It always helps to read the articles about which you post links. It
is stated that the orbit is designed to allow the telescope to work
with the interferometric network of radio telescopes on Earth to
provided higher resolution than can be obttained from the ground.
From this I assume that the ground stations can track the position of
the telescope accurately enough to permit good interferometry to be
done.


http://space.skyrocket.de/doc_sdat/spektr-r.htm

I only noticed the VLBI link _after_ I read this, and revisited the
original link. Somehow it escaped notice on the first read.

I'm truly impressed that they can do space-ground interferometry with a
radio telescope. This will be very valuable.


A high-eccentricity orbit costs less than a low-eccentricity distant
orbit in terms of thrust required, yet it allows the radio telescope
to be at a large distance from Earth about 80-90% of the time (near
apogee) in accord with Kepler's 2nd law of planetary motion.


A subtlety that doesn't appear until you think about it.
  #9  
Old July 27th 11, 09:10 PM posted to sci.astro,sci.physics
Steve Willner
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Posts: 1,172
Default Russia Launches Long-Delayed Deep Space Radio Telescope

In article ,
Yousuf Khan writes:
I'm not even sure why they are doing such an elliptical orbit like that?


As others have mentioned, variable baseline for VLBI and lots of time
spent far from Earth.

This isn't the first VLBI satellite. Halca, sometimes called VSOP,
was launched by Japan in 1997. More details at:
http://www.sciencedirect.com/science...94576501001710

--
Help keep our newsgroup healthy; please don't feed the trolls.
Steve Willner Phone 617-495-7123
Cambridge, MA 02138 USA
 




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