[amsat-bb] Re: Space Debris:
Stephen Melachrinos wrote: were a major hazard to everyone, themselves included. So they must have allocated more resources to the problem, as this is a massive undertaking. (Note that some reports say that the US has about 20,000 objects that are tracked and cataloged. In theory, this means propagating the ephemeris of all of these for some number of days and comparing all possible combinations across the ti! me period of the analysis.) Computers are cheap, so actually propagating the ephemerides of those objects is the easy part. The hard part is that the published elements are simply not accurate enough to reliably predict collisions -- or give sufficient reassurances that a collision won't occur. TS Kelso has written some stuff about this on his website. See http://www.celestrak.com/events/collision/ He's been doing his own conflict predicts for some time. He shows many close approaches that never result in a collision. Yet he did not rate a Iridium 33/Cosmos 2251 collision as especially probable before it happened because the TLE numbers simply aren't accurate enough. ___ Sent via amsat...@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
[amsat-bb] Re: Space Debris:
hi steve, thanks for an informative post. good to see the bb doing what it does best. 73 john g7hia From: Stephen Melachrinos melac...@verizon.net To: amsat-bb@amsat.org Sent: Wednesday, 14 April, 2010 0:22:34 Subject: [amsat-bb] Re: Space Debris: Greg - I didn't see anyone else reply, so I'll try. No, it's not coincidence. After the Iridium collision last year, the US Air Force decided it was in everyone's best interest for them to run conjunction analyses against many more space objects than they had previously analyzed, and report their predictions to system owners. Previously, their concern was primarily the US government's spacecraft, so we (in the amateur community) and many commercial operators never knew what was happening to our birds unless we did (or paid for) the work ourselves. But the collision (as well as the Chinese ASAT demonstration) showed that the resulting debris fields were a major hazard to everyone, themselves included. So they must have allocated more resources to the problem, as this is a massive undertaking. (Note that some reports say that the US has about 20,000 objects that are tracked and cataloged. In theory, this means propagating the ephemeris of all of these for some number of days and comparing all possible combinations across the ti! me period of the analysis.) Unfortunately, many (if not most) of the objects no longer have maneuvering capability. If a vehicle can maneuver, these warnings give them time to try and increase the separation prior to the predicted close approach. (You might have heard of some times when a space shuttle does one of these maneuvers.) But if you can't maneuver (as is the case with AO-51), all we can do is watch and wait. Steve W3HF Apr 13, 2010 01:45:32 AM, ko6th_g...@hotmail.com wrote: Is it just a coincidence that these warnings seem to be coming pretty often recently, or did NORAD change their reporting procedures, or is all the junk up there getting to critical mass where nothing is safe? It seems like we're heading into a situation like nuclear fission, where you get enough stuff interacting, and it sets up a chain reaction of collisions. Greg KO6TH ___ Sent via amsat...@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb ___ Sent via amsat...@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
[amsat-bb] Re: Space Debris: Predicted near impact for AO-51
Did AO-51 survived the approach? On Mon, Apr 12, 2010 at 10:36 PM, Greg D. ko6th_g...@hotmail.com wrote: Is it just a coincidence that these warnings seem to be coming pretty often recently, or did NORAD change their reporting procedures, or is all the junk up there getting to critical mass where nothing is safe? It seems like we're heading into a situation like nuclear fission, where you get enough stuff interacting, and it sets up a chain reaction of collisions. Greg KO6TH Date: Tue, 13 Apr 2010 00:16:59 -0400 From: k...@verizon.net To: amsat-bb@amsat.org Subject: [amsat-bb] Re: Space Debris: Predicted near impact for AO-51 On 4/11/2010 11:45 PM, Tom Clark, K3IO wrote: The Joint Space Operations Center at Vandenberg AFB has reported that AO-51 will have a ~200 meter (i.e. 2 football fields) approach to object #34890 at 08:51Z on April 13th. The Joint Space Command sent an update -- their latest prediction has reduced the 200 meter miss distance to ~135 meters 73, Tom ___ Sent via amsat...@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb _ Hotmail is redefining busy with tools for the New Busy. Get more from your inbox. http://www.windowslive.com/campaign/thenewbusy?ocid=PID28326::T:WLMTAGL:ON:WL:en-US:WM_HMP:042010_2 ___ Sent via amsat...@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb ___ Sent via amsat...@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
[amsat-bb] Re: Space Debris: Predicted near impact for AO-51
--- On Tue, 4/13/10, Larry Teran ki6...@gmail.com wrote: From: Larry Teran ki6...@gmail.com Subject: [amsat-bb] Re: Space Debris: Predicted near impact for AO-51 To: amsat-bb@amsat.org Received: Tuesday, April 13, 2010, 1:33 PM Did AO-51 survived the approach? snip There were several stations operating over it during today's 1400 UTC pass over western North America. Bernhard VA6BMJ @ DO33FL __ Do You Yahoo!? Tired of spam? Yahoo! Mail has the best spam protection around http://mail.yahoo.com ___ Sent via amsat...@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
[amsat-bb] Re: Space Debris: Predicted near impact for AO-51
It seems to me that everyone in LEO is getting warnings now. Unfortunately that crash caused a lot of debris. Delfi-C3 made it through ok, as well as the other cubes on our launch. so good luck to AO-51! Wouter Weggelaar PA3WEG Delfi-C3 mission ops team On Mon, Apr 12, 2010 at 5:45 AM, Tom Clark, K3IO k...@verizon.net wrote: The Joint Space Operations Center at Vandenberg AFB has reported that AO-51 will have a ~200 meter (i.e. 2 football fields) approach to object #34890 at 08:51Z on April 13th. Object #34890 (see http://www.n2yo.com/satellite/?s=34890 and http://celestrak.com/NORAD/elements/iridium-33-debris.txt) is one piece of the more than 500 pieces of debris left over after the Iridium-33 -- Kosmos-2251 collision on Feb. 10,2009 (see http://en.wikipedia.org/wiki/2009_satellite_collision). The total mass of the two spacecraft was about 1600 kg (well over one ton). You can get an HD movie animation of the Iridium/Kosmos collision here (warning -- 50 MB ZIP file). 73, Tom ___ Sent via amsat...@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb ___ Sent via amsat...@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
[amsat-bb] Re: Space Debris: Predicted near impact for AO-51
On 12 Apr 2010 at 12:20, wouter weggelaar wrote: Date sent: Mon, 12 Apr 2010 12:20:23 +0200 From: wouter weggelaar pa3...@amsat.org Subject:[amsat-bb] Re: Space Debris: Predicted near impact for AO-51 To: k...@verizon.net Copies to: AMSAT BB amsat-bb@amsat.org It seems to me that everyone in LEO is getting warnings now. Unfortunately that crash caused a lot of debris. Delfi-C3 made it through ok, as well as the other cubes on our launch. so good luck to AO-51! Wouter Weggelaar PA3WEG Delfi-C3 mission ops team A general question is there is some sort of validation done when a satellite is put on an orbit? Could be due to the low orbit there is no collision avoidance calculus made? The doomed day already happen but is it possible another collision trigger a billard effect in space as per the following site:http://science.nasa.gov/realtime/Jtrack/3D/Jtrack3D.html - Luc Leblanc VE2DWE Skype VE2DWE www.qsl.net/ve2dwe DSTAR urcall VE2DWE WAC BASIC CW PHONE SATELLITE ___ Sent via amsat...@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
[amsat-bb] Re: Space Debris: Predicted near impact for AO-51
On 4/11/2010 11:45 PM, Tom Clark, K3IO wrote: The Joint Space Operations Center at Vandenberg AFB has reported that AO-51 will have a ~200 meter (i.e. 2 football fields) approach to object #34890 at 08:51Z on April 13th. The Joint Space Command sent an update -- their latest prediction has reduced the 200 meter miss distance to ~135 meters 73, Tom ___ Sent via amsat...@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
