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#26 2016-06-15 06:01:02

Tom Kalbfus
Banned
Registered: 2006-08-16
Posts: 4,401

Re: Juno - Jupiter Polar Orbiter

GW Johnson wrote:

Better lifeless Legos than something truly alive.  That's a harsh place. 

GW

I think there is a relatively radiation free zone just above Jupiter's atmosphere, just like there is just above Earth's, if we can get within 200 km above Jupiter's cloud tops, a probe there could last quite a long time. The best way to get into a circular orbit around Jupiter would be with an atmosphere grazing maneuver. You'd need an ablative heat shield to slow down the probe, and then a rocket burn to circularize the orbit afterwards, and like a low Earth orbiting space craft, you'd need periodic rocket burns to keep the probe from falling into the atmosphere. So far only one space agency has ever sent probes to Jupiter or any of the outer planets, that would be NASA. Russia hasn't even sent one probe there.

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#27 2016-06-15 16:30:37

SpaceNut
Administrator
From: New Hampshire
Registered: 2004-07-22
Posts: 23,888

Re: Juno - Jupiter Polar Orbiter

Is it even possible to scoop up enough atmosphere to use a neclear power engine to force the probe back into a higher orbit as it slows each time on its way downward towards the planet efore being boosted back into a more stable orbit....

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#28 2016-06-16 06:11:37

Tom Kalbfus
Banned
Registered: 2006-08-16
Posts: 4,401

Re: Juno - Jupiter Polar Orbiter

SpaceNut wrote:

Is it even possible to scoop up enough atmosphere to use a neclear power engine to force the probe back into a higher orbit as it slows each time on its way downward towards the planet efore being boosted back into a more stable orbit....

You can use atmospheric grazing to slow down to a lower orbit, the only problem is the orbit you end up in without correction is one where part of it dips into the atmosphere, so what you need is a rocket boost at the high end of the orbit to raise up the lower end of the orbit. The atmosphere is great for slowing down without expending propellant, but you need to raise your velocity at the apogee of the orbit so your satellite doesn't dip back down into the atmosphere during the second orbit after slow down. You need to expend a little propellant to circularize you orbit after performing the atmospheric grazing maneuver, otherwise you will slow down even more with the next orbit. So you need to raise the low part of your next orbit so you miss the atmosphere after it has done its job of slowing you down to get you here.

Low Jupiter orbit is much like low Earth orbit, in that there is a trace amount of Jupiter's atmosphere which basically prevent radiation bands from accumulating there. At higher orbits, there is nothing to prevent Jupiter's magnetic field from accumulating charged particles from the sun and creating radiation hazards. In low Jupiter orbit, your orbit will slowly decay just like in Low Earth orbit, but a satellite could stay up there for years with a minimum propellant expenditure to maintain orbit.

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#29 2021-06-07 03:22:50

Mars_B4_Moon
Member
Registered: 2006-03-23
Posts: 1,038

Re: Juno - Jupiter Polar Orbiter

NASA's Juno Spacecraft To Make Closest Visit To Jupiter's Biggest Moon Ganymede On June 7
https://www.republicworld.com/technolog … une-7.html

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#30 2021-06-09 02:42:11

Mars_B4_Moon
Member
Registered: 2006-03-23
Posts: 1,038

Re: Juno - Jupiter Polar Orbiter

Jupiter’s moon Ganymede seen up close for first time in 21 years
https://spaceflightnow.com/2021/06/08/j … -21-years/

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