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What is the delta v required to place a satellite in L2 from earth transfer orbit ( Like the James Webb Telescope )? Does orbits closer to L2 different delta v from orbits far from L2?

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  • $\begingroup$ It is not clear to me whether you are asking for the actual numbers for the JWST (and with the launcher's actual delivery performance) or you are asking for a general theoretical number to reach Sun-Earth L2 from the Earth surface. For the actual numbers we have some ideas given by the actual 2 mid-course correction burns durations, MCC1a and MCC1b (65 minutes and 9+ minutes, resp.). These can be correlated with the analysis by Petersen (cf Table 3). $\endgroup$
    – Ng Ph
    Dec 30, 2021 at 15:03
  • $\begingroup$ (cont.) Accordingly, my calculation gives approximately: 20 m/s (MCC1b+MCC1a). Recall that this corresponds to the intentional "hold back" launch strategy proper to the JWST (because it cannot brake if it goes too fast). So, it remains to know (calculate) the actual Delta-v the JWST got from the launcher at the point it was released. I don't know whether it can be inferred from the public data released by Arianespace/ESA/NASA. $\endgroup$
    – Ng Ph
    Dec 30, 2021 at 15:18
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    $\begingroup$ @NgPh I am looking for general delta v for sun-earth L2 insertion. $\endgroup$
    – Ashvin
    Dec 31, 2021 at 17:00
  • $\begingroup$ Then you should make that explicit in your question. You may consider also to add precisions as from where you consider the "insertion" to start (from Earth? from LEO?, ...), how long to stay around L2, and whether you are looking for minimum transfer time or minimum fuel (maximum payload), etc ... $\endgroup$
    – Ng Ph
    Jan 2 at 20:57
  • $\begingroup$ @NgPh edited the question body on your suggestion $\endgroup$
    – Ashvin
    Jan 3 at 15:39

1 Answer 1

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Getting from LEO to Earth-Sun L2

(source: https://www.researchgate.net/figure/3-Duration-and-delta-v-requirements-of-a-SEL-2-servicing-mission_tbl8_319122341)

Departure: 3.23km/s Arrival: 0.9km/s

Note that this is to the actual L2 point.

Second part of your question.. To match a Halo orbit around L2 such as the JWST uses, would require a small amount more departure delta-v, and very very little (<50m/s) of arrival delta-v.
The JWST will actually not slow down when it gets near its Halo Orbit, but will speed up by another tiny bit, to insert itself into the orbit.

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  • $\begingroup$ "this is to the actual L2 ... to match a Halo orbit around L2 such as the JWST uses, would require a small amount more departure delta-v, and very very little (<50m/s) of arrival delta-v". Can you expand? ... what is "small amount more"? Where did you get the upper bound <50m/s for arrival from? $\endgroup$
    – Ng Ph
    Jan 5 at 21:00

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