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Atlas 3B ascent and fuel dump may be visible from N.East America
An Atlas 3B rocket is scheduled to lift off from Cape Canaveral on 2005 Feb
03 at 07:41 UTC (2:41 AM EST). I expect the launch window to begin 14 min earlier for each day of any launch delay. Coverage of the launch is available he http://www.spaceflightnow.com/atlas/ac206/status.html http://streamvox.streamos.com/gemssv/ils012705/ Observers in parts of North America may be able to spot a couple of seldom seen events: the ascent trajectory, and the Centaur upper stage's propellant dump. The ascent trajectory is unusual in that it will track toward the northeast, not far off the east coast of the U.S.A. and Canada. The rocket is likely to remain in Earth's shadow during all or most of the ascent, so the its plume may not be very bright. I suggest scanning with 7x50 binoculars. Here is an Excel spreadsheet containing a rough estimate of the ascent trajectory, including formula's to compute azimuth and elevation for your location: http://satobs.org/seesat_ref/AC-206/...ook_angles.xls You need only enter the lift-off time, and your latitude and longitude. The lift-off time need not be UTC. The co-ordinates of the example are for Washington, D.C. I am not certain steeply the rocket will climb, so the spreadsheet covers two scenarios: the one labelled "Low MECO1" assumes the vehicle will be 240 km above the Earth at main engine cut-off #1; "High MECO1" assumes it will have climbed to 640 km. I suspect that the low scenario is correct. The Centaur upper stage's propellant dump occurs less than 2 hours after launch. When illuminated by the sun, Centaur propellant clouds have been seen with the unaided eye at distances of tens of thousands of kilometres. The Centaur propellant dump from the Atlas 2AS launched on 2004 Aug 31 UTC, was visible to the unaided eye at ranges in excess of 8000 km, for about 10 min after it ended. I spotted it while in progress, at a range of about 6300 km, as a glowing cloud about the apparent diameter of the moon. Binoculars revealed considerable structure in the plume. The exact time of the Atlas 3B's propellant dump has not been published; however, based upon typical practice, if the launch occurs on Feb 3, and on time, it should be completed by about 09:35 UTC. That would put the dump within Earth's shadow; however, it would pass into sunlight about 4 min later, 09:39 UTC, near 53 N, 82 W, altitude 1161 km, becoming visible to observers in the northeast. A cursory analysis indicates some visibility at least as far west as Chicago, and at least as far south as Washington D.C. Of course, if the dump occurs much earlier or later than usual, then there would be little to see over North America. To assist as many people as possible to see this event, Heavens-Above kindly has agreed to host the estimated orbital elements. To run your own predictions, go to this page: http://www.heavens-above.com Select or enter your site co-ordinates, then from the main page, click "Select a satellite from the database", and enter 70999 in the box labelled "US Space Command ID", and follow the instructions to generate custom pass predictions. Be careful to ignore predictions for dates and times prior to lift-off. The estimated orbital elements should be accurate to within about 5 min of time and several deg of arc, but it is a good idea to allow for even more error. For those who prefer to run their own predictions, here are estimated elements, in 2-line format: MES2 1010 X 1208 km 1 70999U 05034.37193286 .00000000 00000-0 00000-0 0 08 2 70999 63.4167 155.0000 0132437 179.7272 98.8000 13.39694040 03 Description of 2-line elements: http://www.satobs.org/element.html I will update this information as events warrant. Ted Molczan |
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Ted Molczan wrote:
An Atlas 3B rocket is scheduled to lift off from Cape Canaveral on 2005 Feb 03 at 07:41 UTC (2:41 AM EST). I expect the launch window to begin 14 min earlier for each day of any launch delay. (snip) To assist as many people as possible to see this event, Heavens-Above kindly has agreed to host the estimated orbital elements. To run your own predictions, go to this page: http://www.heavens-above.com I wondered why that "Atlas 3B launch" had appeared there without a matching launch. I looked for the satellite but saw nothing (which at least proves I'm not troubled by creative eyesight). The predicted orbital elements are similar to the ones given for recent NOSS launches, so there may be two satellites associated with this launch. --Bill Thompson |
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"William R. Thompson" wrote in message
... Ted Molczan wrote: An Atlas 3B rocket is scheduled to lift off from Cape Canaveral on 2005 Feb 03 at 07:41 UTC (2:41 AM EST). I expect the launch window to begin 14 min earlier for each day of any launch delay. (snip) To assist as many people as possible to see this event, Heavens-Above kindly has agreed to host the estimated orbital elements. To run your own predictions, go to this page: http://www.heavens-above.com I wondered why that "Atlas 3B launch" had appeared there without a matching launch. I looked for the satellite but saw nothing (which at least proves I'm not troubled by creative eyesight). The predicted orbital elements are similar to the ones given for recent NOSS launches, so there may be two satellites associated with this launch. Yes, I was especting a new NOSS pair, and the confirming observation was made within 2 hours of launch: http://satobs.org/seesat/Feb-2005/0027.html Here is an improved elset based upon that obs: 1 70999U 05034.37193287 .00000000 00000-0 00000-0 0 09 2 70999 63.4167 162.0800 0132437 179.7272 103.5500 13.39694040 08 Should be accurate to within several minutes of time, after 24 h. Afer a few days of tracking, the uncertainty will reduce to a fraction of a second - at least until they manoeuvre. Over the next month or so, they are likely to make several small manoeuvres to fine tune the orbit. Ted Molczan |
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Ted Molczan wrote:
(snip) Yes, I was especting a new NOSS pair, and the confirming observation was made within 2 hours of launch: http://satobs.org/seesat/Feb-2005/0027.html Here is an improved elset based upon that obs: 1 70999U 05034.37193287 .00000000 00000-0 00000-0 0 09 2 70999 63.4167 162.0800 0132437 179.7272 103.5500 13.39694040 08 Should be accurate to within several minutes of time, after 24 h. Afer a few days of tracking, the uncertainty will reduce to a fraction of a second - at least until they manoeuvre. Over the next month or so, they are likely to make several small manoeuvres to fine tune the orbit. Thanks. Will heavens-above post more pre-launch predictions for new satellites? I didn't see anything this time, but maybe I'll get lucky next time. --Bill Thompson |
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When I was a kid in I think 1988 me and my friends were outside during
summer break playing hide and seek in the dark. Over the southwest horizon I seen what appeared to be a meteor getting very bright moving very fast. I yelled for my parents to come outside and we watch this thing that looked like a balastic missle flying across the sky. You could even tell it had some giant letters down the side. You could actually hear it flying through the air since everything was dead quite with this missle overhead. About a minute later it disappeard across the north west horizon. Didn't see no bright flash or mushroom cloud so we went inside and watched the news. =) Come to find out it was a russian booster rocket reentering the atmosphere and burned up before impact. It was very cool and VERY scary. |
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Thread | Thread Starter | Forum | Replies | Last Post |
Atlas 3B ascent and fuel dump may be visible from N.East America | Ted Molczan | Amateur Astronomy | 2 | February 4th 05 03:32 PM |