Re: ISAR Spectrum FLIGHT 2

From: Dillon Shropshire via Seesat-l <seesat-l_at_lists.seesatmail.org>
Date: Mon, 16 Mar 2026 14:55:37 -0400
ISAR Spectrum FLIGHT 2
edit: "the launch window DOES ALLOW FOR A 'Twilight Effect' as the upper
stage travels over the North Pole"

On Mon, Mar 16, 2026 at 2:37 PM Dillon Shropshire <
dillon.shropshire2006_at_gmail.com> wrote:

> As we close in on the second test flight of ISAR's Spectrum rocket, I have
> released preliminary Predictive TLEs derived from completed Marine and Air
> Hazard Notices.
>
> Available here and on my website: https://dillonsspacepage.com/pretle
> (Check website for updated RAAN values as launch time changes occur)
>
>
> NET: Mar 19 2026 20:00:00 UTC
> Onward and Upward PO                                        192000.00
> 1 70044U 26057A   26078.83935185  .00000000  00000-0  00000-0 0  9990
> 2 70044  97.3943 154.0733 0254696 083.2149 000.0000 15.62204037    04
> Onward and Upward                                           192000.00
> 1 70044U 26057A   26078.87128472  .00000000  00000-0  00000-0 0  9997
> 2 70044  97.3943 154.0407 0004731 083.2244 179.6270 15.05080073    02
>
> Estimating a ~548 x 555km x 97.39 deg orbit (exact eccentricity unknown)
>
> The launch window does inhibit a 'Twilight Effect' as the upper stage
> travels over the North Pole... for
> observers in UK/Northern EU I would be watching around 1hr 37mins into
> flight for the upper stage to exit Earth's shadow. This MAY be accompanied
> by fuel venting post de-orbit burn.
>
> Hazard Map Snapshots
> https://ibb.co/FLrmrHGs
> https://ibb.co/4RnNRDQ2
> https://ibb.co/B2z0F2Kt
>

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Received on Mon Mar 16 2026 - 11:56:08 UTC

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