Will Perseverance be captured into Mars orbit before descent or would it be a direct descent into the atmosphere similar to an aerocapture maneuver? It would be helpful if someone could add any references to the orbit trajectory around mars before the descent into the atmosphere!
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I would suspect that the rover is capture into a stable orbit beforehand, which would allow for greater precision in landing site, and the landing timeframe. In saying this, however, I'm sure NASA's instruments are perfectly capable of hitting a target from across the sun. – R. Hall Feb 09 '21 at 04:26
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1@ReubenFarley-Hall there's no rocket and propellant for orbital capture. – uhoh Feb 09 '21 at 05:53
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see also Why do you need a heat shield on Mars entry if the atmosphere is so thin? and When things land on Mars what fraction of their velocity do they remove propulsively? and Are there any studies or technology envisioned for Mars entry and landing without a parachute? and Does the Mars2020 lander need a new parachute design? – uhoh Feb 09 '21 at 05:54
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No. Perseverance will not enter Martian orbit before descent. It would be a direct descent. For reference, here's a picture of Perseverance's landing procedure.
A spacecraft entering into orbit before descent requires a fair bit of fuel. The thrusters on the Backshell are only there for mid-course corrections and for stability during descent. It does not have the delta-v to slow down enough to enter Martian orbit. Also, what would be the need to enter orbit? Mars rotates, so the trajectory is designed to intercept the surface at the desired location. So of course, accuracy is very important. If the spacecraft arrives 6 hours later for example, it would be thousands of kilometers off from the landing site because of the rotation of Mars. Though there is the guided entry phase which can to some degree control where the spacecraft will land.
Star Man
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1If you had some reason to, you could aerobrake into orbit mostly for free, but it would be considerably more complex than just going straight to the ground, I think. You'd need a bit of fuel to circularize and for descent, but it wouldn't be much. You'd really want a good reason to go through the trouble, though. – J... Feb 09 '21 at 19:04
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1@J... Well, by entering orbit, it would be possible to delay the landing if the weather conditions are bad – wrtlprnft Feb 09 '21 at 21:51
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1@wrtlprnft That said, with 1% of Earth atmosphere, a gale force wind isn't really anything to get worked up about... and I don't think there's a monsoon season in Jezero Crater. – J... Feb 09 '21 at 23:21
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@wrtlprnft great point! I've just asked Are launch windows to Mars avoided if they result in landings during dust storm season? – uhoh Feb 11 '21 at 02:53
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