Author Topic: Atlantis heading home Friday - ISS may need to avoid Chinese debris  (Read 7721 times)


Offline Andrewwski

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Is the possible debris confirmed?  I know a few months ago there were unfounded rumors on this.
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Offline ShuttleDiscovery

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"..and 932 will be pathfinder"

What does that mean, that plane (932) will be escorting the SCA?

Offline sfxtd

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ShuttleDiscovery - 25/6/2007  11:57 PM

"..and 932 will be pathfinder"

What does that mean, that plane (932) will be escorting the SCA?

I assume it means flying ahead of the SCA to warn of clear-air turbulence and such.

Online eeergo

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Andrewwski - 26/6/2007 8:13 AM Is the possible debris confirmed? I know a few months ago there were unfounded rumors on this.

I saw two or three months ago a UN report (which I assume it's not unfounded ;) ) offering a prediction of the debris' trajectories. There was even a slide showing that in one year or so -I don't remember the figure- the debris would be spread over the whole globe.

So it's only a matter of time before these encounters happen. And I guess they'll be turning even more frequent (and with less avoidance distance than the current predicted 17 km) with the passing months. Lovely stupid military tests...

I can't find the actual link to that report, but I think it'd been posted by Philip (psloss)...

-DaviD-

Online Chris Bergin

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Andrewwski - 26/6/2007  7:13 AM

Is the possible debris confirmed?  I know a few months ago there were unfounded rumors on this.

The information is from an official NASA documented from last night. Not sure how that could be an unfounded rumor?

Offline Andrewwski

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No, I wasn't referring to this one.  I know that there were unfounded rumors a few months ago, and I was hoping to clarify that this was not a rebirth of the old ones.

Not that I should worry - I know everything you put on this site is credible.  Another reason why I love it so much. :)
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Online Chris Bergin

Ah ok. Thanks :)

Speaking of which (on this debris event), we're waiting to hear if the ISS was required to make a DAM.

*Paging Jim Oberg*

Offline avitek

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Computer program SOCRATES at the Celestrack site gives for TLEs for 2007-06-26 01:00 UTC those parameters for close encounter between ISS and FY-1C debris:




   
   
   
   
   
   
   
   

   
   
   

   
   
   
   
   
   
   
   

   
   
   
   
   
   

ActionNORAD
Catalog
Number
NameDays
Since
Epoch
Max
Probability
Dilution
Threshold
(km)
Min
Range
(km)
Relative
Velocity
(km/sec)
Start
(UTC)
TCA
(UTC)
Stop
(UTC)
 25544ISS (ZARYA)0.9874.985E-062.9924.23114.465
29719FENGYUN 1C DEB1.1892007 Jun 26 20:26:51.6472007 Jun 26 20:26:51.8312007 Jun 26 20:26:52.015


Offline STS Tony

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avitek - 26/6/2007  1:31 PM

Computer program SOCRATES at the Celestrack site gives for TLEs for 2007-06-26 01:00 UTC those parameters for close encounter between ISS and FY-1C debris:

What exactly does that all mean? Can you translate it?

Offline Almurray1958



the website itself explains the factors and definitions very clearly.  Basically it takes the 2-line TLE for any 2 objects and calculates the orbital conjunctions.   How close, when, relative velocity, and other parameters.

pretty neat.



http://celestrak.com/SOCRATES/

while this page  http://celestrak.com/SOCRATES/top10maxprob.asp exlains the exact definitions of the values.

- Al Murray

Offline Jorge

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STS Tony - 26/6/2007  3:33 PM

Quote
avitek - 26/6/2007  1:31 PM

Computer program SOCRATES at the Celestrack site gives for TLEs for 2007-06-26 01:00 UTC those parameters for close encounter between ISS and FY-1C debris:

What exactly does that all mean? Can you translate it?

TLE - Two Line Elements. A format used by NORAD to describe the orbit of a spacecraft.

Celestrak - (http://celestrak.com/). A website run by Dr. T. S. Kelso that publishes TLEs from NORAD's Satellite Catalog (SATCAT).

SOCRATES - (http://celestrak.com/SOCRATES/). Satellite Orbital Conjunction Reports Assessing Threatening Encounters in Space. A service that computes conjunctions (close encounters/potential collisions) between payloads and all objects in the SATCAT.

UTC - Universal Time Coordinated. Roughly equivalent to Greenwich Mean Time (GMT). Standard timetag for TLEs.

ISS - International Space Station. Self-explanatory.

FY-1C - Fengyun 1C. A defunct Chinese satellite that was used as a target for a recent Chinese ASAT test, which produced a lot of debris in low Earth orbit.
JRF

Online Chris Bergin

ISS did not conduct a DAM, after further predictions conducted by US and Russian Ballistics that were conducted today.

Offline Launch Fan

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Chris Bergin - 26/6/2007  6:48 PM

ISS did not conduct a DAM, after further predictions conducted by US and Russian Ballistics that were conducted today.

Still leaves the question on how much notice they get for these possible collision avoidance moves?

Offline Jorge

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Launch Fan - 26/6/2007  9:47 PM

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Chris Bergin - 26/6/2007  6:48 PM

ISS did not conduct a DAM, after further predictions conducted by US and Russian Ballistics that were conducted today.

Still leaves the question on how much notice they get for these possible collision avoidance moves?

At least 36 hours for the shuttle. For ISS, at least that long, if not longer.
JRF

Offline avitek

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Jorge - 27/6/2007  5:29 AM

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Launch Fan - 26/6/2007  9:47 PM

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Chris Bergin - 26/6/2007  6:48 PM

ISS did not conduct a DAM, after further predictions conducted by US and Russian Ballistics that were conducted today.

Still leaves the question on how much notice they get for these possible collision avoidance moves?

At least 36 hours for the shuttle. For ISS, at least that long, if not longer.

According to the very informative article in April 2001 issue of Orbital Debris Quarterly News, see

http://www.orbitaldebris.jsc.nasa.gov/newsletter/pdfs/ODQNv6i2.pdf

on page 4, at least 72 hours before TCA. There is in the mentioned article the whole collision avoidance procedure described in detail.

Online Chris Bergin

Atlantis might be back in one day now. Working on NASA information on L2. Will do an article.

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