Friday, March 5, 2021

When to launch 2L4

Today we use the Hop David spreadsheet, to get Cycler 2L4's launch window after Year 2000.

Probably the 2004 or 2012 transits of Venus would have been better but on a 243 Julian year scale, as you will see, Why Two-Kays is close enough. For more precision in later synods the Manifold Thesis had a decent "brute force" writeup on how to estimate departure moments. Overall this blog shall leave the Pork Chop Plots to the unparalleled experts in bacon consumption, namely NASA.

G-d and His Spreadsheet deliver B30, δW; and B32, δAngle @J2000... Themself. Since I'm going Venus outbound B30 is -225.1878256° and B32 is -81.5153°. (Earth-to-Venus, these are positive.) Our job is to find B24.

For me that starts with B20, the travel-time in sidereal years of the destination (Earth). We just got that: 159 / 365.25636. B22 tells us that in degrees: 156.5. B24 just orients that in the 180° semicircle for 23.5° angle at launch window.

The 2000 date of departure comes from adding 2000 to that fraction of Earth sidereal.

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