Re: Cygnus return? Gulf of Mexico debris warning

From: satcom ops via Seesat-l <seesat-l_at_satobs.org>
Date: Mon, 11 Jan 2021 09:12:19 +0000
https://www.spacedaily.com/reports/SpaceX_Dragon_Capsule_to_Make_First_of_Its_Kind_Science_Splashdown_999.html



Regards

John



On 09/01/2021 10:09, Bob Christy wrote:
> Sleep is a wonderful thing!
> 
> There is another explanation for the dispersed areas, with clues in the navigation warning for the Crew Dragon return in 2020. Thanks, John, for providing it.
> 
> The areas represent a decision that can be made relatively last minute.
> 
> The orbital period in the post-undocking phase of the mission can be used to 'aim' Dragon at the chosen zone.
> 
> The areas allow a range of Ascending Node longitudes.
> 
> The associated ground tracks avoid overflights of major urban areas, like Orlando and Jacksonville, in the closing stages to cover for debris-shedding or the vehicle falling short of the target.
> 
> Bob Christy
> 
>> On 8 Jan 2021, at 22:13, Bob Christy <bob_at_zarya.info> wrote:
>>
>> I've taken a closer look at the areas in the navigation warning.
>>
>> They represent the aim points for the Dragon CRS-21 splashdown on successive (almost) days.
>>
>> Undocking is set for Jan 11 which after Dragon will manoeuvre down to an orbit with a period of about 88.8 minutes.
>>
>> If re-entry has to be waved off for any reason on Jan 12 then opportunities are available over the following few days.
>>
>> Splash points are:
>> Jan 12 - Zone A
>> Jan 13 - no attempt, final few km of ground track would pass directly over Orlando.
>> Jan 14 - Zone B
>> Jan 15 - Zone C
>> Jan 16 - Zone D
>>
>> Zones A, B and C are in the Atlantic Ocean.
>>
>> Zone D is to the west of Florida in the Gulf of Mexico. The reason may be because an Atlantic splashdown would require the track to pass directly over Jacksonville in its final moments.
>>
>> The navigation warning omits the times for Jan 16.
>>
>> Bob Christy
>>
>>
>>> On 8 Jan 2021, at 11:56, satcom ops via Seesat-l <seesat-l_at_satobs.org> wrote:
>>>
>>> https://postimg.cc/jwbmmp08
>>>
>>> 080821Z JAN 21
>>> NAVAREA IV 26/21(11).
>>> WESTERN NORTH ATLANTIC.
>>> GULF OF MEXICO.
>>> FLORIDA.
>>> 1. HAZARDOUS OPERATIONS, SPACE DEBRIS
>>>   IN AREAS BOUND BY:
>>>   A. 120150Z TO 120220Z JAN, ALTERNATE
>>>      140100Z TO 140130Z AND
>>>      150035Z TO 150105Z JAN
>>>      29-20-45N 080-13-48W, 28-50-56N 079-43-04W,
>>>      28-21-14N 080-13-48W, 28-50-56N 080-44-31W.
>>>   B. 120155Z TO 120225Z JAN, ALTERNATE
>>>      140105Z TO 140135Z AND
>>>      150045Z TO 150115Z JAN
>>>      30-17-45N 080-35-59W, 29-47-56N 080-04-58W,
>>>      29-18-14N 080-35-59W, 29-47-56N 081-07-01W.
>>>   C. 120200Z TO 120230Z JAN, ALTERNATE
>>>      140110Z TO 140140Z AND
>>>      150045Z TO 150115Z JAN
>>>      31-24-45N 080-15-00W, 30-54-56N 079-43-36W,
>>>      30-25-14N 080-15-00W, 30-54-56N 080-46-23W.
>>>   D. 120200Z TO 120230Z JAN, ALTERNATE
>>>      140110Z TO 140140Z AND
>>>      150050Z TO 150120Z JAN
>>>      28-59-45N 083-45-00W, 28-29-56N 083-14-20W,
>>>      28-00-14N 083-45-00W, 28-29-56N 084-15-39W.
>>> 2. CANCEL THIS MSG 150220Z JAN 21.
>>> -- 
>>> Regards
>>>
>>> John

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Received on Mon Jan 11 2021 - 03:13:31 UTC

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