How would a manned mission enter Jovian orbit?

[willpittenger]

In a previous thread we established that manned missions would not be able to safely go inside the Europan orbit. So how would the spacecraft enter the Jovian system with orbiting in mind? Arthur C. Clarke had the Leonov entering Jovian orbit via aerobraking. In <i>2001</i> (movie version), I suspect the Discovery would have used its engines in a maneuver similar to what Galileo used in real life. Both of the fiction options would take the spacecraft inside the deadly region we have to avoid.<br /><br />So could we enter the system using flybies of the outer moons? <div class="Discussion_UserSignature"> <hr style="margin-top:0.5em;margin-bottom:0.5em" />Will Pittenger<hr style="margin-top:0.5em;margin-bottom:0.5em" />Add this user box to your Wikipedia User Page to show your support for the SDC forums: <div style="margin-left:1em">{{User:Will Pittenger/User Boxes/Space.com Account}}</div> </div>

 

[PistolPete]

Perhaps if high Isp propulsion systems such as ion drives or VASIMR are perfected then the spacecraft could slowly retrograde thrust itself into a safe enough orbit without having to dip into the high Jovian atmosphere. <div class="Discussion_UserSignature"> <p> </p><p><em>So, again we are defeated. This victory belongs to the farmers, not us.</em></p><p><strong>-Kambei Shimada from the movie Seven Samurai</strong></p> </div>

 

[vogon13]

Have a big nuke go off on Callisto first, and aerobrake the manned vehicle by flying through the plume.<br /><br /> <div class="Discussion_UserSignature"> <p><font color="#ff0000"><strong>TPTB went to Dallas and all I got was Plucked !!</strong></font></p><p><font color="#339966"><strong>So many people, so few recipes !!</strong></font></p><p><font color="#0000ff"><strong>Let's clean up this stinkhole !!</strong></font> </p> </div>

 

[no_way]

one crazy option would be to have a momentum exchange tether deployed before manned craft gets there, and use that for braking. It would have to be massive though, and if you miss the rendezvous, its "bye-bye solar system"<br />

 

[crix]

LOL, you're trying to send Discovery to Jovian orbit??? <br /><br />Ohhh, sorry, I thought you meant the Shuttle OV. hah

 

[3488]

I think that the only option is to brake into orbit like Galileo or as <br />Discovery in 2001 A Space Odyssey did. There is no way to avoid the inner radiation filled <br />environment. Yes perhaps Callisto or Ganymede could be used to help slow the <br />craft on final approach (as Io did for the Galileo Spacecraft).<br /><br />However the spacecraft would not have to remain long close to jupiter, as the initial orbit will be <br />a huge ellipse, after the first Perijove, & the second Perijove could be aimed at <br />a point close to Ganymede.<br /><br />I like vogon13's idea though. If you dont get microwaved by Jupiter's radiation belt, <br />you could get nuked instead near Callisto!!!! <img src="/images/icons/laugh.gif" /> <img src="/images/icons/laugh.gif" /> <img src="/images/icons/laugh.gif" /><br /><br />Andrew Brown. <div class="Discussion_UserSignature"> <p><font color="#000080">"I suddenly noticed an anomaly to the left of Io, just off the rim of that world. It was extremely large with respect to the overall size of Io and crescent shaped. It seemed unbelievable that something that big had not been visible before".</font> <em><strong><font color="#000000">Linda Morabito </font></strong><font color="#800000">on discovering that the Jupiter moon Io was volcanically active. Friday 9th March 1979.</font></em></p><p><font size="1" color="#000080">http://www.launchphotography.com/</font><br /><br /><font size="1" color="#000080">http://anthmartian.googlepages.com/thisislandearth</font></p><p><font size="1" color="#000080">http://web.me.com/meridianijournal</font></p> </div>

 

[vulture2]

The Jovian radiation belt consists of trapped particles, mainly electrons at <20MEV, not cosmic rays. A reasonable thickness of lead (~1cm?) or spacecraft structure of similar mass around a small storm shelter could protect the crew during a brief aerobraking pass. <br />

 

[willpittenger]

The radiation would be a concern again. Sorry. <div class="Discussion_UserSignature"> <hr style="margin-top:0.5em;margin-bottom:0.5em" />Will Pittenger<hr style="margin-top:0.5em;margin-bottom:0.5em" />Add this user box to your Wikipedia User Page to show your support for the SDC forums: <div style="margin-left:1em">{{User:Will Pittenger/User Boxes/Space.com Account}}</div> </div>

 

[willpittenger]

In the older thread I mentioned, it was established that you would need several <font color="yellow"><i>meters</i></font>of lead. See Docm's 1st and 2nd posts on the subject. <div class="Discussion_UserSignature"> <hr style="margin-top:0.5em;margin-bottom:0.5em" />Will Pittenger<hr style="margin-top:0.5em;margin-bottom:0.5em" />Add this user box to your Wikipedia User Page to show your support for the SDC forums: <div style="margin-left:1em">{{User:Will Pittenger/User Boxes/Space.com Account}}</div> </div>

 

[docm]

Charged particles like electrons, protons etc. circulating in Jupiters magnetic field cause a problem addressed in the other thread; huge fluxes of cyclotron gamma radiation. <br /><br />Many materials can filter electrons effectively at the cost of generating Bremsstrahlung (braking) radiation (x-rays & gammas), which reinforces the cyclotron emissions. <br /><br />Bremsstrahlung is used to generate diagnostic x-rays, usually by impacting electrons on a Tungsten target at energies < .4 MeV. For these purposes a few mm of lead is enough. For gammas produced by 20 MeV electrons much more would be required. <br /><br />If any of these gamma energies get above 7.4 MeV photoneutrons can be produced <i>in the shielding</i>. Photoneutrons = free neutrons expelled from nuclei by energetic photons. <br /><br />This creates a whole other shielding issue; when the neutrons are finally absorbed (not easy) the emission of yet another gamma is often the case. That and parts of the structure exposed to said neutrons could become radioactive over time.<br /><br />In short; radiation management in Jupiter space is a freaking nightmare. <div class="Discussion_UserSignature"> </div>

 

[MeteorWayne]

"In short; radiation management in Jupiter space is a freaking nightmare. "<br /><br />A very short and concise description of the very complicated processes <img src="/images/icons/laugh.gif" /> <div class="Discussion_UserSignature"> <p><font color="#000080"><em><font color="#000000">But the Krell forgot one thing John. Monsters. Monsters from the Id.</font></em> </font></p><p><font color="#000080">I really, really, really, really miss the "first unread post" function</font><font color="#000080"> </font></p> </div>

 

[crix]

Agreed. What a facinating invisible environment in that region. I don't expect humans to venture past Mars for a long time, and then certainly not without our "Borg-ish" upgrades.

 

[baktothemoon]

Just raise shields, lol

 

[vulture2]

Requirements for shielding for habitation for years and for a single aerobraking pass of a few hours are quite different. A dose rate of 5 rem/hr would be lethal in 100 hours but perfectly acceptable for two hours. Shielding requirements are thus more or less inversely proportional to duration of exposure. However, how is the crew going to get back out of the Jovian gravity well? When we have the technology for that, aerobraking may be unnecessary.

 

[solarspot]

"I don't expect humans to venture past Mars for a long time, and then certainly not without our "Borg-ish" upgrades."<br /><br />Isn't this mostly an issue at Jupiter? I personally think Jupiter will be the last planet to be explored by humans... Mercury through Neptune (exception of Jupiter) may all have permanent populations before we start with Jupiter... But if propulsion technology advances further than radiation shielding tech. does, we may send the first Jovian explorers to moons outside Jupiter's main radiation belts...<br /><br /><br />

 

[vogon13]

If our ballute picks up some radioactivity from the Callisto braking nuke, it doesn't matter too much since the ballute is discarded.<br /><br />Even if our manned craft doesn't get too much closer to Jupiter, it will still need radiation shielding for the radiation belts there (remember how they stretch out anti-sunward, and Callisto passes back there every orbit) so if we need to bump up the shielding a couple of percent to tolerate the braking nuke, well, we still have a mission.<br /><br /><br /> <div class="Discussion_UserSignature"> <p><font color="#ff0000"><strong>TPTB went to Dallas and all I got was Plucked !!</strong></font></p><p><font color="#339966"><strong>So many people, so few recipes !!</strong></font></p><p><font color="#0000ff"><strong>Let's clean up this stinkhole !!</strong></font> </p> </div>