All,
Hours after the launch of AO-85 (ex FOX-1A) the first TLEs for 8 of the 13 launched Cubesates were published under GRACE 1 through 8. I have not seen any updates since launch day.
Today around 18:00 UTC AO-85 was 29 s early compared to the TLE set for GRACE 8, which is currently leading the group. AO-85 is 41 s early compared to the TLE set for GRACE 2, that most people will be using now.
So either the early TLEs were not very accurate yet, or the TLEs for AO-85 were not yet determined and therefore not available in the initially measured batch. Let's hope we get updated TLEs for all 13 Cubesats soon.
BTW, there appears to be a small temperature drift on the downlink signal frequency of AO-85 that may be noticable when using automatic doppler correction.
73, Nico PA0DLO
Nico,
The first keps we got were based on the OPMs at the time of P-POD deployment per the telemetry. We will likely not receive any others until NORAD starts tracking them, perhaps in a few days. Still, those will not be available to the general public (from what I understand), they will be posted in our AMSAT keps when we get them.
Thank you for the information on the frequency drift!
Jerry Buxton, NØJY
On 10/10/2015 15:31, Nico Janssen wrote:
All,
Hours after the launch of AO-85 (ex FOX-1A) the first TLEs for 8 of the 13 launched Cubesates were published under GRACE 1 through 8. I have not seen any updates since launch day.
Today around 18:00 UTC AO-85 was 29 s early compared to the TLE set for GRACE 8, which is currently leading the group. AO-85 is 41 s early compared to the TLE set for GRACE 2, that most people will be using now.
So either the early TLEs were not very accurate yet, or the TLEs for AO-85 were not yet determined and therefore not available in the initially measured batch. Let's hope we get updated TLEs for all 13 Cubesats soon.
BTW, there appears to be a small temperature drift on the downlink signal frequency of AO-85 that may be noticable when using automatic doppler correction.
73, Nico PA0DLO
Sent via [email protected]. AMSAT-NA makes this open forum available to all interested persons worldwide without requiring membership. Opinions expressed are solely those of the author, and do not reflect the official views of AMSAT-NA. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://www.amsat.org/mailman/listinfo/amsat-bb
All,
Initially the TLEs for the GRACE Cubesats were published only via: http://mstl.atl.calpoly.edu/~ops/grace_tle/GRACE_OPM_TLE.txt
Meanwhile more recent TLEs can be found in this list: http://mstl.atl.calpoly.edu/~ops/keps/kepler.txt
Using these TLE sets I find that AO-85 is closest to object 90747, GRACE_47. Actually AO-85 is now about 10 s early compared to the TLEs of object 90747.
I assume Cal Poly will keep these GRACE elements up-to-date in the coming days, like they do with the ULTRASat TLEs.
73, Nico PA0DLO
On 2015-10-10 22:38, Jerry Buxton wrote:
Nico,
The first keps we got were based on the OPMs at the time of P-POD deployment per the telemetry. We will likely not receive any others until NORAD starts tracking them, perhaps in a few days. Still, those will not be available to the general public (from what I understand), they will be posted in our AMSAT keps when we get them.
Thank you for the information on the frequency drift!
Jerry Buxton, NØJY
On 10/10/2015 15:31, Nico Janssen wrote:
All,
Hours after the launch of AO-85 (ex FOX-1A) the first TLEs for 8 of the 13 launched Cubesates were published under GRACE 1 through 8. I have not seen any updates since launch day.
Today around 18:00 UTC AO-85 was 29 s early compared to the TLE set for GRACE 8, which is currently leading the group. AO-85 is 41 s early compared to the TLE set for GRACE 2, that most people will be using now.
So either the early TLEs were not very accurate yet, or the TLEs for AO-85 were not yet determined and therefore not available in the initially measured batch. Let's hope we get updated TLEs for all 13 Cubesats soon.
BTW, there appears to be a small temperature drift on the downlink signal frequency of AO-85 that may be noticable when using automatic doppler correction.
73, Nico PA0DLO
Sent via [email protected]. AMSAT-NA makes this open forum available to all interested persons worldwide without requiring membership. Opinions expressed are solely those of the author, and do not reflect the official views of AMSAT-NA. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://www.amsat.org/mailman/listinfo/amsat-bb
Sent via [email protected]. AMSAT-NA makes this open forum available to all interested persons worldwide without requiring membership. Opinions expressed are solely those of the author, and do not reflect the official views of AMSAT-NA. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://www.amsat.org/mailman/listinfo/amsat-bb
All,
The TLEs for the GRACE Cubesats in the Cal Poly list have been updated. http://mstl.atl.calpoly.edu/~ops/keps/kepler.txt
Based on these new TLEs it is now certain that AO-85 is object 90747, GRACE-47 in the Cal Poly list. In the official JSpOC Catalog AO-85 is object 40967, 2015-058D.
73, Nico PA0DLO
On 2015-10-11 09:26, Nico Janssen wrote:
All,
Initially the TLEs for the GRACE Cubesats were published only via: http://mstl.atl.calpoly.edu/~ops/grace_tle/GRACE_OPM_TLE.txt
Meanwhile more recent TLEs can be found in this list: http://mstl.atl.calpoly.edu/~ops/keps/kepler.txt
Using these TLE sets I find that AO-85 is closest to object 90747, GRACE_47. Actually AO-85 is now about 10 s early compared to the TLEs of object 90747.
I assume Cal Poly will keep these GRACE elements up-to-date in the coming days, like they do with the ULTRASat TLEs.
73, Nico PA0DLO
On 2015-10-10 22:38, Jerry Buxton wrote:
Nico,
The first keps we got were based on the OPMs at the time of P-POD deployment per the telemetry. We will likely not receive any others until NORAD starts tracking them, perhaps in a few days. Still, those will not be available to the general public (from what I understand), they will be posted in our AMSAT keps when we get them.
Thank you for the information on the frequency drift!
Jerry Buxton, NØJY
On 10/10/2015 15:31, Nico Janssen wrote:
All,
Hours after the launch of AO-85 (ex FOX-1A) the first TLEs for 8 of the 13 launched Cubesates were published under GRACE 1 through 8. I have not seen any updates since launch day.
Today around 18:00 UTC AO-85 was 29 s early compared to the TLE set for GRACE 8, which is currently leading the group. AO-85 is 41 s early compared to the TLE set for GRACE 2, that most people will be using now.
So either the early TLEs were not very accurate yet, or the TLEs for AO-85 were not yet determined and therefore not available in the initially measured batch. Let's hope we get updated TLEs for all 13 Cubesats soon.
BTW, there appears to be a small temperature drift on the downlink signal frequency of AO-85 that may be noticable when using automatic doppler correction.
73, Nico PA0DLO
Sent via [email protected]. AMSAT-NA makes this open forum available to all interested persons worldwide without requiring membership. Opinions expressed are solely those of the author, and do not reflect the official views of AMSAT-NA. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://www.amsat.org/mailman/listinfo/amsat-bb
Sent via [email protected]. AMSAT-NA makes this open forum available to all interested persons worldwide without requiring membership. Opinions expressed are solely those of the author, and do not reflect the official views of AMSAT-NA. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://www.amsat.org/mailman/listinfo/amsat-bb
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Jerry Buxton -
Nico Janssen