+Happy Humphrey Posted July 14, 2006 Share Posted July 14, 2006 Real Time Satellite tracking ...you can select other satellites or space telescopes. Quote Link to comment
+The Flying Boots Posted July 14, 2006 Share Posted July 14, 2006 Wow!!!! Thats amazing Quote Link to comment
+The Forester Posted July 14, 2006 Share Posted July 14, 2006 That site is also starred in another thread. Anyone else got any entries in the SuitSat competion? I'm hoping that a geocacher wins at least one of the entry classes. At the moment I'd put a fiver on Nobby's entry. Norad's Kepplerian parameters consistently underestimate the B* (orbital decay) rate, though I dunno why. This is why the official estimate of six weeks to re-entry when the thing was launched was so badly wrong. It seems to be getting later and later in the year that re-entry can reasonably be expected, so a later estimate is likely to be more accurate than an early one. Plenty of time for more British geocachers to enter the competition! Let's see if we can beat the Americans!! Quote Link to comment
+minstrelcat Posted July 14, 2006 Share Posted July 14, 2006 That site is also starred in another thread. Anyone else got any entries in the SuitSat competion? I'm hoping that a geocacher wins at least one of the entry classes. At the moment I'd put a fiver on Nobby's entry. Norad's Kepplerian parameters consistently underestimate the B* (orbital decay) rate, though I dunno why. This is why the official estimate of six weeks to re-entry when the thing was launched was so badly wrong. It seems to be getting later and later in the year that re-entry can reasonably be expected, so a later estimate is likely to be more accurate than an early one. Plenty of time for more British geocachers to enter the competition! Let's see if we can beat the Americans!! How do you view the entries? Lisa Quote Link to comment
+The Forester Posted July 14, 2006 Share Posted July 14, 2006 You can only view your own entry on the website, but on the other thread some of us (well, two of us so far!) are uploading our entries onto the geocaching forum. I've changed my mind about the date several times already and will no doubt change it again. One of the peculiar rules of the game is that you are allowed to change your entered date as many times as you wish. That's a bit of flaw in the game because as the re-entry gets closer and closer, it will become easier and easier to predict the date of the final burnup. The day before re-entry it will be very obvious when it's going to enter the upper atmosphere at a low enough altitude to cause burnup and competitors will be able to cheat by revising their entered date. I think the competition organisers should put a cutoff limit, say 45 days before predicted re-entry, to make the thing less predictable and even more fun. Quote Link to comment
+yob kulcha Posted July 14, 2006 Share Posted July 14, 2006 Discovery is moving at a helluva lick. It's only taken a few minutes to travel the length of Australia. Those guys must have an amazing view. Quote Link to comment
+yob kulcha Posted July 14, 2006 Share Posted July 14, 2006 My GPS says it's reading from Satellites 17, 22 and 28. Which satellites do those numbers refer to? They don't seem to relate to the NAVSTAR GPS Operational Satellites. And which one is the Satellite of Love? Quote Link to comment
+Johnmelad Posted July 14, 2006 Share Posted July 14, 2006 Real Time Satellite tracking ...you can select other satellites or space telescopes. Thanks for the link, an excellent site. Quote Link to comment
+The Forester Posted July 14, 2006 Share Posted July 14, 2006 (edited) My GPS says it's reading from Satellites 17, 22 and 28. Which satellites do those numbers refer to? They don't seem to relate to the NAVSTAR GPS Operational Satellites. OK, I'll bite. Different organisations have different numbering systems for satellites. Your GPSr uses the PRN to identify each GPS satellite. Lemme explain how it works. All GPS satellites transmit on exactly the same frequency as eachother. To enable your GPSr to differentiate between the satellites it is 'hearing', each satellite sends a pseudo-random number which identifies itself to you. There are currently 30 satellites in the NavStar (GPS) constellation, with PRNs from 1 to 30, logically enough. PRN 17 is also known as SV (Satellite Vehicle) 57. Note that PRNs are recycled when a particular satellite reaches the end of its working life. SV 57, which is currently transmitting PRN17 is called 57 because it was the 57th GPS satellite to be launched. SV57 is called 28874 by NORAD (the USAF Command which tracks all orbiting satellites) quite simply because it was the next object after 28873 which needed a number to be assigned to it. Those numbers are assigned to any piece of material in orbit, just so long as it can be tracked by radar or optically. The International Designator for PRN17/SV57/28874 is 2005-038A. The International Designator system has the year of launch followed by the launch number in that year and the final letter indicates which piece of the launch it refers to. The main payload is traditionally given the letter A, as in this case, but other pieces such as nosecone fairings and discarded upper stages of the launch vehicle are also given letters. For example, the latest satellite to be launched was an accident. Two of the Shuttle crewmen were piddling about in the open payload bay, experimenting with some new gunk which is being developed to repair broken, cracked or missing heatshield tiles on the leading edges of the Orbiter's airframe. One of the guys 'dropped' (if that's the word) one of his spatulas and didn't notice that he'd released it from its lanyard. The spatula floated off and has become a satellite in its own right. NORAD has assigned it the number of 29257 and its International number is 1998-067AJ. The reason why it's been given a 1998 number is that when the spatula was lost, the Shuttle was attached to the part of the ISS which was launched in 1998 and was numbered 67 as it was the 67th launch that year. The AJ suffix is the sequential alphanumeric which counts all the various bits of junk which have become separated from the ISS over the years. That little spatula, which is about the size of a domestic kitchen knife, is whizzing around the Earth at a hell of a speed and if it should ever collide with a spacecraft of any type, the results would be catastrophic. For that reason NORAD will continue to track it until it re-enters the Earth's atmosphere and it burns up. PRN22 is SV53, SpaceCom's number is 28129 and the Int number is 2003-058A. It is also assigned the number USA 175. Those numbers are assigned to major operational satellites, such as spysats, telecomm sats, Nav sats etc, and indicate the nation of origin. Russian ones are given the letters CIS. PRN28 is SV48, SpaceCom's number is 26401 and the Int number is 2000-040A. It is also assigned the number USA 151. Even supersecret spysats, whose very existence might be officially denied, are given USA numbers. For example, USA144 is known to be a spysat of a type which is known as Misty2 has an official number, despite the fact that it's orbital location is supposed to be a secret. Locrosse 3 is another example of a very poorly concealed secret. If you take a look at the Heavens Above website you can see a full description of the Lacrosse 3 radar spysat's orbit, despite the fact that the US government wants to keep it a secret. Armed with nothing more than a pair of binoculars you can see Lacrosse 3 (aka Onyx 3) for yourself. I watched it passing over Forester Towers a couple of nights ago and shall watch its next orbit tonight. With the Improved Crystal optical spysats, sometimes known by their now obsolete codename of 'Keyhole', it can be fun to watch them watching us watching them. The KH-12 sats are very similar to the Hubble space telescope, only they look downwards instead of upwards and outwards and they don't have the crappy mirror shape that Hubble has. It can be fun to watch a Keyhole sat passing overhead and even more fun to 'moon' the bugger! Edited July 14, 2006 by The Forester Quote Link to comment
nobby.nobbs Posted July 15, 2006 Share Posted July 15, 2006 just because you can change you guess doesn't mean you should!!! my guess was calculated using all the scientific knowledge of your average sandfly.... ie a total shot in the dark but lets try to beat the americans anyhow. Quote Link to comment
+yob kulcha Posted July 15, 2006 Share Posted July 15, 2006 OK, I'll bite. Wow. Thanks for taking the time to write such an informative reply. I appreciate it and I'll look into the subject a bit more deeply now. Quote Link to comment
+The Blorenges Posted July 16, 2006 Share Posted July 16, 2006 (edited) You might like this site too - http://science.nasa.gov/Realtime/jtrack/3d/JTrack3d.html - the view of the earth from space with every satellite and bit of space junk showing! It's crowded up there folks! You will need the Java plug in installed to view it. This is also excellent - http://www.heavens-above.com - if you put your home coords in (use the database to search by country/place its excellent) you get timings of when these satellites will appear in your bit of sky. Particularly interesting are the Iridium flares - can be very bright (and I mean bright!) flashes of light in the night sky. For timings use something like the TV Ceefax clock as it has to be accurate to a second. Chris Edited July 16, 2006 by The Blorenges Quote Link to comment
barryhunter Posted July 16, 2006 Share Posted July 16, 2006 For timings use something like the TV Ceefax clock as it has to be accurate to a second. Or your GPS clock, that should be pretty accurate too! Quote Link to comment
+Johnmelad Posted July 16, 2006 Share Posted July 16, 2006 http://science.nasa.gov/Realtime/jtrack/3d/JTrack3d.html Can't get the link to work! Quote Link to comment
+The Blorenges Posted July 16, 2006 Share Posted July 16, 2006 For timings use something like the TV Ceefax clock as it has to be accurate to a second. Or your GPS clock, that should be pretty accurate too! The link seems to work when I clicked it - When you say it didn't work did you mean it comes up page not found or it goes to the site but you don't get any information. If the latter you do need the Java plug in installed on your PC - Thats maybe the problem. Go to http://www.java.com/en/ - Quote Link to comment
+Johnmelad Posted July 16, 2006 Share Posted July 16, 2006 For timings use something like the TV Ceefax clock as it has to be accurate to a second. Or your GPS clock, that should be pretty accurate too! The link seems to work when I clicked it - When you say it didn't work did you mean it comes up page not found or it goes to the site but you don't get any information. If the latter you do need the Java plug in installed on your PC - Thats maybe the problem. Go to http://www.java.com/en/ - Site not found... Quote Link to comment
+Johnmelad Posted July 16, 2006 Share Posted July 16, 2006 Must have been a glitch, I have access now... Quote Link to comment
+kyot Posted July 16, 2006 Share Posted July 16, 2006 My GPS says it's reading from Satellites 17, 22 and 28. Which satellites do those numbers refer to? They don't seem to relate to the NAVSTAR GPS Operational Satellites. as above... except for #33 == PRN124 == Artemis #39 == PRN120 &126 == Inmarsat (I think I've the numbers right; maybe not!) which are the geostationary sats doing the differential corrections for EGNOS (EU kind of WAAS) Quote Link to comment
+Andy&BeckyRiley Posted July 17, 2006 Share Posted July 17, 2006 You guys would love my 'Dr Ivan's dates cache' ;-) Andy Quote Link to comment
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