RE: Launch window question

From: Erkenswick, Tom M. \(JSC-CM341\) via Seesat-l <"Erkenswick,>
Date: Thu, 28 May 2020 12:46:37 +0000
Caveat:  I'm not working this mission in any form, so I can't give this answer with 100% certainty with respect to this mission.

This article from Air & Space discusses generically the planar window and the phase window.  The planar window for a northern launch direction comes once every day, but the phase window (as Richard describes below) does not overlap with the planar window every day.  I have no idea if there are any illumination requirements, or if that just happens to be correlative at this time.


-----Original Message-----
From: Seesat-l <> On Behalf Of Marco Langbroek via Seesat-l
Sent: Thursday, May 28, 2020 5:33 AM
To: Richard Cole <>;
Subject: [EXTERNAL] Re: Launch window question

Op 28-5-2020 om 11:56 schreef Richard Cole:
> Marco,
> As a guess, and I haven't run the numbers, there is a window of ISS 
> position around the orbit (with respect to the Cape, at the launch 
> time) that can be accessed within the period after launch allowed for 
> in the mission timeline, which seems to be around 20hrs. The ISS is 
> within that window on the 27th, 30th and 31st, but not the 28th or 
> 29th. The instantaneous launch window is obviously set by the ISS orbital plane and changes by a fixed period for each day.

I think Richard is on the right track

Upon further analysis:

The choosen launch dates, assuming a similar 19-hour time-window between launch and docking, all result in docking while on the nightside of earth. While the two dates inbetween result in docking on the dayside of the earth.

So illumination concerns seem to guide the choice here. Daytime might be avoided so as not to be blinded by the sun, perhaps.

- Marco

PS: my question was sparked because it popped up in a Zoom launchparty with a bunch of Dutch science writers and space people which I participated in yesterday. Nobody had a clear answer right away, but I think we have an answer now! Thanks to the hive mind!

Dr Marco Langbroek  -  SatTrackCam Leiden, the Netherlands.

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Twitter: _at_Marco_Langbroek
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Received on Thu May 28 2020 - 07:48:18 UTC

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