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Probes designed to orbit planets can use aerobraking to help orbit insertion (as it has already been done for Mars Reconnaissance Orbiter or Mars Global Surveyor). Such techniques could be used for all planets that have an atmosphere (Venus, Saturn, Jupiter,...). Probes have been sent into orbit of such planets (Galileo, Juno for Jupiter; Venera for Venus,...).

My question is: for each planet with an atmosphere in orbit to which a space probe has been sent (in 2019), has aerobraking already been used to help slow down for orbit insertion and if not, why?

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  • $\begingroup$ Orbit Insertion is the act of entering a stable orbit around a planet. An orbit touching atmosphere is not stable and poses a high risk (since aerodynamics of probes are hard to control), you'll need a semi-unpredictable amount of fuel to lift the perigee out of the atmosphere again (and another burn to fix the apogee, plus possibly fix the orientation and rotational speed). My guess is that it is just safer to just insert into orbit with a set of powerful burns. $\endgroup$ – Infrisios Jul 11 '19 at 7:24
  • $\begingroup$ @Infrisios the fact that is has already been done (e.g. Mars Reconnaissance Orbiter) make me think there are serious advantages of using this method. $\endgroup$ – Manu H Jul 11 '19 at 7:36
  • $\begingroup$ Of course there are! It's possible and it has great advantages, mainly that you save significant amounts of fuel (so your payload can be larger), but it also comes with a risk. I don't know a ton about it, which is why I used a comment instead of an answer to give you some insight about what I know. $\endgroup$ – Infrisios Jul 11 '19 at 8:43
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You are confusing aerobraking with aerocapture.

Aerobraking is used to circularize an elliptical orbit into a circular one after orbit insertion, and it has been used a few times on the following missions:

  • Hiten: this was a demonstration mission in Earth orbit
  • Magellan: Around Venus
  • Mars Global surveyor
  • Mars Odyssey
  • Mars Reconnaissance Orbiter
  • Venus Express
  • Exomars Trace Gas Orbiter

Aerobraking has never been attempted with gas giants.

Aerocapture is using a body's atmosphere to slow down a spacecraft for orbit insertion. It's been investigated but never used as a technique. A spacecraft would need thermal protection and enhanced structural strength to survive the maneuver, which adds weight. It's a risky option: if you get it wrong the spacecraft either re-enters and is destroyed or skips off and heads off into deep space. The risk doesn't seem to be worth the cost savings.

Aerobraking can be much more gentle and controllable, taking place over many orbits, controllers can measure orbit change on each pass to understand the spacecraft's actual interaction with the atmosphere. Aerocapture is a one-shot deal.

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  • $\begingroup$ Not so much circularisation (because if you aerobrake to a circular orbit, you're reentering) as apoapsis lowering $\endgroup$ – JCRM Jul 11 '19 at 10:20

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