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Here is why I expect an orbit raise of #HTV9 somewhere this afternoon: the orbital altitude of HTV 9 so far compared to that of HTV 7 from 2018, a clear analogue.
Red and blue are HTV 9 apogee and perigee: gray is HTV 7.
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Same pattern is also visible with other HTV missions: orbit circularization (mainly perigee raise) about 0.5 days into the mission: and next clear orbit raise some 3 to 3.5 days into the mission.
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So I expect HTV 9 to have moved into a higher orbit tonight compared to this morning, which is why predictions based on a current orbit will be incorrect for tonight!
4/4
Based on the analogy with HTV 7, I expect #HTV9 to manoeuvre into this higher orbit at around 19:05 UT today.
5/5
I have tried to forecast the new orbit. If my forecast is correct, the first European twilight pass will see it 1.5 minutes later, the second midnight pass 3.5 minutes later, compared to predictions based on the old orbit.
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