is this a real tracking? or is it just a computation of the orbit? I mean, if the telescope gets blown up by the evil alien spaceship will it vanish from the animation above?
9:32 PM, May 17, 2007
Navneeth said...
Another great place to get satellite pass information for your location is Heavens Above. Another software that I use is called Orbitron, which lets you track and provide predictions for every kind of satellite out there. Also, I recall seeing some site that would let you track satellites via Google Earth, but I don't recall the name of the site!
Bee, I'm quite sure it's just orbit computation. ;-)
Is this a real tracking? or is it just a computation of the orbit?
Hm... good question...
I was first so naive as to assume that these are indeed real-time satellite data. But it seems it's not quite so James Bondish... The website referred to by ESA, www.n2yo.com, has a FAQ, but they do not explain in detail where the satellite postion data actually come from.
ESA writes on its page About the ESA Satellite Tracker: The satellite location data is combined with map images provided by Google maps, plus formatting instructions, and automatically updated on our portal. The actual satellite locations are updated every hour. What does this mean?
Now, at a second look, I have found on the n2yo.com site an info page about the satellites, for example here for the Hubble Space Telescope. It contains all kind of mission information and data, and, at the end of the page, a "Two Line Element Set (TLE)" which seems to be updated on an hourly basis.
This Two-line Element Set contains all kind of detailed information about the orbit, including drag term parameters.
So, my guess is that the satellite positions are extrapolated from the latest available TES data set. This means it's a calculated position, but the calculation is anchored in a quite recent, acutal orbit determination of the satellite. But if some Blofeld (I'm less with aliens ;-) destroys the HST, there won't be immediately a red blinking light instead of the satellite icon...
Best, stefan
9:28 AM, May 19, 2007
D. Scuka said...
The TLE position data that is being generated by n2yo.com and integretaed into the ESA tracker is actually generated by NORAD. NORAD in turn obtains the position data through their space survey activities (radar, optical). In other words, they track every object up there, so, yes, the track generated from the TLE data sets (which are updated hourly) is 'real' but it would take, I guess, at least a few hours for the TLE data to reflect the absence of an actual object if it were to suddenly be zapped by the space aliens.
BTW, are there constant radio links to all these satellites that would notify any kind of "loss" immediately?
Best, stefan
3:52 PM, May 23, 2007
Daniel Scuka said...
Some sats are only in contact with the ground via specific ground station(s) during fixed pass times. If the space aliens kidnapped one in between passes, no one might notice until the start of the next pass. But of course, many sats are in full-time ground com via a relay satellite in geostationary orbit (including ESA's Envisat), which are themselves in full-time contact with the ground.
"Where is the Hubble Space Telescope?"
11 Comments -
When ISS FUBAR overflies North America we must all hoist our laser pointers and irradiate it. Burn, you worthlesss piece of drakh, burn!
10:57 AM, May 17, 2007
Haha. I used to have trackers on my desktop. And everytime something went over belgium, i looked out of my window. Didn't see anything ;).
2:58 PM, May 17, 2007
is this a real tracking? or is it just a computation of the orbit? I mean, if the telescope gets blown up by the evil alien spaceship will it vanish from the animation above?
9:32 PM, May 17, 2007
Another great place to get satellite pass information for your location is Heavens Above. Another software that I use is called Orbitron, which lets you track and provide predictions for every kind of satellite out there. Also, I recall seeing some site that would let you track satellites via Google Earth, but I don't recall the name of the site!
Bee,
I'm quite sure it's just orbit computation. ;-)
2:21 AM, May 18, 2007
Is this a real tracking? or is it just a computation of the orbit?
Hm... good question...
I was first so naive as to assume that these are indeed real-time satellite data. But it seems it's not quite so James Bondish... The website referred to by ESA, www.n2yo.com, has a FAQ, but they do not explain in detail where the satellite postion data actually come from.
ESA writes on its page About the ESA Satellite Tracker: The satellite location data is combined with map images provided by Google maps, plus formatting instructions, and automatically updated on our portal. The actual satellite locations are updated every hour. What does this mean?
Now, at a second look, I have found on the n2yo.com site an info page about the satellites, for example here for the Hubble Space Telescope. It contains all kind of mission information and data, and, at the end of the page, a "Two Line Element Set (TLE)" which seems to be updated on an hourly basis.
This Two-line Element Set contains all kind of detailed information about the orbit, including drag term parameters.
So, my guess is that the satellite positions are extrapolated from the latest available TES data set. This means it's a calculated position, but the calculation is anchored in a quite recent, acutal orbit determination of the satellite. But if some Blofeld (I'm less with aliens ;-) destroys the HST, there won't be immediately a red blinking light instead of the satellite icon...
Best, stefan
9:28 AM, May 19, 2007
The TLE position data that is being generated by n2yo.com and integretaed into the ESA tracker is actually generated by NORAD. NORAD in turn obtains the position data through their space survey activities (radar, optical). In other words, they track every object up there, so, yes, the track generated from the TLE data sets (which are updated hourly) is 'real' but it would take, I guess, at least a few hours for the TLE data to reflect the absence of an actual object if it were to suddenly be zapped by the space aliens.
2:30 AM, May 23, 2007
Hi D. Scuka,
thank you very much for these explanations!
BTW, are there constant radio links to all these satellites that would notify any kind of "loss" immediately?
Best, stefan
3:52 PM, May 23, 2007
Some sats are only in contact with the ground via specific ground station(s) during fixed pass times. If the space aliens kidnapped one in between passes, no one might notice until the start of the next pass. But of course, many sats are in full-time ground com via a relay satellite in geostationary orbit (including ESA's Envisat), which are themselves in full-time contact with the ground.
2:29 AM, May 25, 2007
Hi Daniel,
thank you again for this info -
and many greetings from Frankfurt to Darmstadt :-)
Best, stefan
8:16 PM, May 25, 2007
Thanks!
It's raining here in Darmstadt! :-)
5:51 AM, May 28, 2007
You should check out this ESA series on the Hubble.
http://www.youtube.com/view_play_list?p=8DCB3F2E1AF98B48
10:42 AM, February 13, 2008