Hacker News Reader

There very specific times you can launch to establish desired orbits. Typically these windows only come once every month or two.

View on HN

Is that the case for an orbit around the earth-sun Lagrange point? It seems like anytime should be GTG

True. I don't think this is an orbital launch window thing. Rather, the date seemed to be driven by operational necessities (range safety, weather, the practicalities of getting the rocket ready etc).

I believe the launch windows are fairly constrained due to the precise positioning requirements as well as the requirement to avoid eclipses throughout the lifetime of the telescope. This study [1] was for a planned 2018 launch, but I'm sure there were similar constraints in this time period too.

In addition, the fuel required to position the spacecraft varies a lot depending on the day - and any fuel saved can be used to prolong the operational lifetime of the telescope.

[1] https://issfd.org/ISSFD_2014/ISSFD24_Paper_S2-6_Yu.pdf

Reply on news.ycombinator.com