Ø When there is a launch of several satellites in a single payload, several cubesats for example, I assume they release each at different locations on the deployer trajectory. Preliminary keps are based on the trajectory when each is released?
Ø Otherwise if they were released all at once, how would NORAD know which is which?
Doesn’t much matter when they are released, they still are all in the same orbit more or less for quite a while. Even if the springs release them at 1/2 meter per second, they are all going at 7000 meters per second so it takes days for them to separate very much.
Let’s see, at ½ meter per second separation, then they are 100’ apart after the first minute, 1 mile after the first hour. And not until they are a few miles apart can NORAD distinguish them enough to start getting good tracks on them. By then it is impossible to know which is which. Hence the guessing game until each owner decides which object best fits his downlink experience.
Continuing on, they will be 24 miles apart after the first day where they will be about 5 seconds apart when tracked from the ground. After a week, then maybe 175 miles and ½ minute apart. After a month, maybe 750 miles and 2 minutes apart. After a year, maybe 9000 miles and 30 minutes apart. And finally, after about a year and a half, they will be half an orbit or about 45 minutes apart, beyond which, they start getting closer again…
Something like that unless I screwed up…
Bob
Bob The following link is of Picodragon and 2 other satellites being released or launched. There is a picture and short video. http://amsat-uk.org/tag/picodragon/
73 John KC0BMF
On Mon, Nov 25, 2013 at 9:54 AM, Robert Bruninga bruninga@usna.edu wrote:
Ø When there is a launch of several satellites in a single payload, several cubesats for example, I assume they release each at different locations on the deployer trajectory. Preliminary keps are based on the trajectory when each is released?
Ø Otherwise if they were released all at once, how would NORAD know which is which?
Doesn’t much matter when they are released, they still are all in the same orbit more or less for quite a while. Even if the springs release them at 1/2 meter per second, they are all going at 7000 meters per second so it takes days for them to separate very much.
Let’s see, at ½ meter per second separation, then they are 100’ apart after the first minute, 1 mile after the first hour. And not until they are a few miles apart can NORAD distinguish them enough to start getting good tracks on them. By then it is impossible to know which is which. Hence the guessing game until each owner decides which object best fits his downlink experience.
Continuing on, they will be 24 miles apart after the first day where they will be about 5 seconds apart when tracked from the ground. After a week, then maybe 175 miles and ½ minute apart. After a month, maybe 750 miles and 2 minutes apart. After a year, maybe 9000 miles and 30 minutes apart. And finally, after about a year and a half, they will be half an orbit or about 45 minutes apart, beyond which, they start getting closer again…
Something like that unless I screwed up…
Bob _______________________________________________ Sent via AMSAT-BB@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
participants (2)
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John Fickes -
Robert Bruninga