Manned Mission to Jupiter's Moon Callisto

[liquidspace2k]

I was reading an article on Space.com about the Hibernation thing that ESA is studing and it mentioned that NASA is doing a study about bringing humans to Jupiter's Moon Callisto for a 5 year mission which 30 days would be on the surface.. its suppose to take place in the year 2045 or later... You think it could be sensibly done by 2045.. <br /><br /><br /><br />A Sleepy Science: Will Humans Hibernate Their Way Through Space?<br /><br />http://www.space.com/scienceastronomy/scitues_hibernation_041012.html<br /><br />A 2002 conceptual study by NASA's Revolutionary Aerospace Systems Concepts (RASC) group, the HOPE Callisto mission proposes sending six humans on a 5-year flight to Callisto, where they would spend 30 days on the Jupiter moon's surface, by the year 2045 or later.

 

[omegamogo]

30 Days after a 5 year mission seems too short, why not say, 6 months? Or is there technical reasons for the timing?<br /><br />And 2045?! Thats more then 40 years, to damn long to wait for <img src="/images/icons/frown.gif" /> (hmm, Hibernation...)

 

[yurkin]

A manned Mars mission in forty years seems reasonable. A think a Jovian-lunar mission by that time frame is far too optimistic.

 

[tuckerfan]

Seems to me that by that time we should have the propulsion problem worked out, so that astronauts wouldn't need to hibernate. I mean, at 1 G continous thrust, we could be at Pluto in about a month! It's not like we don't have the technology <i>now</i> to do this, either. Anyone for an Orion-class ship? Anyone?

 

[jmilsom]

I have to agree. Space travel is appealing, but the whole idea of spending five years in space for a thirty day mission - I think it would send any human stark, raving mad. (Doesn't Callisto get too much radiation from Jupiter anyway?)<br /><br />I believe any long term manned missions in the future should all revolve around setting up permanent stations, manned or robotic. And you’d have to plan for far more time on the ground.<br /><br />The focus of the article though is hibernation. Interesting ideas, interesting research. It features so much in SciFi movies and books, humans in hibernation or stasis making long trips through space.<br /><br />I like the line, what kind of hibernaculum should they have. Hmmm, I guess they would have to choose from the current range of hibernacula currently on the market. Personally, I would go for the new Hiberio2000, tastefully appointed hibernaculum, lined in green velvet with ……. <br /> <div class="Discussion_UserSignature"> </div>

 

[liquidspace2k]

i believe for an only 30 day mission on the surface, it could be done better with robots.. i believe to send humans to Callisto for only 30 days is a waste of money.. but then again it depends on what they are going to do there... <br /><br />i think i understand why it would only be 30 days cause of the radiation from Jupiter.. don't want to leave human in extremely high radiation for long times..

 

[halman]

Tuckerfan,<br /><br />From where I am standing, 40 years is a wildly optimistic time frame for coming up with a propulsion system capable of continuous 1 g acceleration for any length of time. I look back on the last 40 years and see a short period of tremendous advances, ten years of no activity, 5 years of steady development, and then a long period of little progress. So much depends on how much money is allocated to space exploration, and for how long.<br /><br />It is reasonable to believe that in 40 years we will have nuclear powered ion propulsion systems, but even those would probably not operate continuously, due to a lack of reaction mass. And an Orion propelled spacecraft would go through 1000's of nuclear warheads to maintain 1 g to Jupiter.<br /><br />The Solar System is a very BIG place. The most likely travel times to Jupiter are in excess of a year, even using nuclear powered ion drives, and probably closer to 2 years. <div class="Discussion_UserSignature"> The secret to peace of mind is a short attention span. </div>

 

[CalliArcale]

<blockquote><font class="small">In reply to:</font><hr /><p>i think i understand why it would only be 30 days cause of the radiation from Jupiter.. don't want to leave human in extremely high radiation for long times..<p><hr /></p></p></blockquote><br /><br />Actually, that might just be why they're thinking about Callisto instead of, say, Europa. Anybody know if Callisto is far enough out to be reasonably safe?<br /><br />I agree with those who say that 2045 is laughably overoptimistic for this. But then, NASA is often doing studies like this as an exercise, even if no actual mission is being seriously considered. It's sort of like the studies the military does to work out a strategy if, for instance, Canada invaded the US. It's not likely to ever happen, but the hypothetical situation does help exercise the brains of those who will have to devise strategies for actual military engagements. <div class="Discussion_UserSignature"> <p> </p><p><font color="#666699"><em>"People assume that time is a strict progression of cause to effect, but actually from a non-linear, non-subjective viewpoint it's more like a big ball of wibbly wobbly . . . timey wimey . . . stuff."</em>  -- The Tenth Doctor, "Blink"</font></p> </div>

 

[meteo]

Callisto: 0.01 rem/day<br />Ganymede: 8 rem/day<br />Europa: 540 rem/day<br />Io: 3600 rem/day!<br />Thebe and inner satellites: 18,000 rem/day!<br /><br />Since Callisto is outside the main radiation belts of Jupiter you would be getting 10mrem/day. I'm guessing that would be comparable or less than smoking a pack a day. I would think Callisto is probably the best place in the outer solar system to settle. So maybe the 30-day restriction is orbital? While Europa may have better prospects for life 540rem/day would be kill you pretty fast.<br /><br />Calliso may have a salty ocean itself but you have to go through much much more crust to get to it (124 miles). Although maybe you could find a thin spot due to a crater, but even in that case I think it would be undrillable.

 

[thalion]

^<br />Where did you get those radiation figures? Just curious.<br /><br />I think the best opportunity for outer planets exploration will be with nuclear thermal propulsion, like the long-cancelled NERVA. If we could cut the transit time to Jupiter down to a year with such a device, the mission could be feasible. With chemical rockets, though, fugedaboutit. Pure fission propulsion would be even better, but that's a long, long way off.

 

[CalliArcale]

<blockquote><font class="small">In reply to:</font><hr /><p>Since Callisto is outside the main radiation belts of Jupiter you would be getting 10mrem/day. I'm guessing that would be comparable or less than smoking a pack a day<p><hr /></p></p></blockquote><br /><br />Just curious, but wouldn't it be more useful to compare it to another common source of radiation, such as dental x-rays? Cigarette smoke, while carcinogenic, is not particularily radioactive. <div class="Discussion_UserSignature"> <p> </p><p><font color="#666699"><em>"People assume that time is a strict progression of cause to effect, but actually from a non-linear, non-subjective viewpoint it's more like a big ball of wibbly wobbly . . . timey wimey . . . stuff."</em>  -- The Tenth Doctor, "Blink"</font></p> </div>

 

[paleo]

An observation. I have no idea if we could send a 'fast' man-carrying spacecraft to jupiter within 50 years but we are absolutly no where near puting a human safely in some type of hibernation within 50 years. The biological and medical challenges are stagering.

 

[meteo]

A rem is a "Roentgen Equivalent in Man" it's a health effects term. I have seen it applied to smoking often, I'm not sure it this is 'technically right.'<br /><br />An ordinary American receives about 360 mrem annually from natural and medical sources. So 10x what you get on normally. Or just within federal guidelines for occupational limits. <br /><br />A rem is a subjective term.<br /><br />Rem:<br />"The rem, an acronym for Roentgen Equivalent Man, was developed in response to evidence that biologic effects per rad of various radiations are often different. The dose equivalent (DE) is defined as the absorbed dose (rads) multiplied by a quality factor (QF), a term that expresses the differences in biologic effectiveness of various types of radiation as compared to x-rays. The QF is a function of the linear energy transfer (LET) of the radiation. The QF for x-rays, gamma-rays, and beta particles with a maximum energy of greater than 30 KeV is 1.0. This category represents a majority of radioactive materials used at UCSF. For information, the QF for neutrons and protons with energies less than 10 MeV is 10 (30 for irradiation of the eyes); for alpha particles from natural radionuclides the QF is 10."<br /><br />Roentegen<br />"The roentgen (R) was adopted in l928 as a unit of exposure to medium-energy x-radiation. It is the approximate exposure to one gram of radium located one yard away for one hour (i.e. one gram of radium produces an exposure rate at one yard of approximately one R/hour). Specifically, the roentgen is the quantity of x- or gamma rays that produce 2.58 x 10- 4 coulombs/kg of air at standard conditions of temperature and pressure. In measuring the roentgen, a known volume of air is irradiated, and the ions produced (electrical charge) are collected and measured. The choice of air as a standard substance was for convenience. Since air and water have an effective atomic number that is nearly the same as that of tissue, absorption of x-ray energy per gram o

 

[mikejz]

Actually I am thinking about it and in some ways I think human exploration of the jovian moons will actually be easier than a long term stay on our own moon. First off the abundance of water means that you only need to bring enough propellant for part of the trip-plus consumables are greatly reduced. You could land on one moon, use electrolysis to break down the water and use it to get to your next destination. Second, the creation of pressurized volumes with lots of radiation shielding will not be as hard as on the moon due to icy composition---most of the exploration will be done below the surface.

 

[liquidspace2k]

From Meteo: <br /><br />Callisto: 0.01 rem/day <br /><br />An ordinary American receives about 360 mrem annually from natural and medical sources.<br />_____________________________________________<br />I might see it now, 30 days on Callisto is about the same as staying on Earth for a year as far as mREM goes<br /><br />So if we designed a space suit to block 10% of the radiation then that would equal to that on Earth.. <br /><br />Does anyone know how much REM the Earth's Moon receives

 

[bobvanx]

Should we ever wish to colonize the outer solar system, Callisto is a pretty natural place to build up. While it is within Jupiter's gravity well and so it's expensive to get anywhere else in terms of deltaV, the volume of water ice makes it very attractive.<br /><br />Regarding energy, a conductive tower pointing at Jupiter would slice through the magnetosphere, generating vast quantities of electricity. Heck, conductive cables along the surface might be enough.

 

[mikejz]

Speaking of which I am wondering outside of one proposal no real use of electro-teathers have been looked at for powering ultra high mission to jupiter. A teather could generate tons and tons of power.

 

[halman]

meteo,<br /><br />I haven't read the article which inspired this thread, but I got the impression that studying hibernation is the primary goal of the mission. If the crew is to spend most of their time in hibernation, consumables might be a limiting factor for any periods of activity. One of the big benefits of hibernation is the reduction of weight dedicated to food, water, and air if the crew is in hibernation. The lighter the spacecraft, the faster the transit times. (Generally speaking.) <div class="Discussion_UserSignature"> The secret to peace of mind is a short attention span. </div>

 

[mrmorris]

<font color="yellow">A teather could generate tons and tons of power. </font><br /><br />You get nothing for free. Electrodynamic tethers produce energy by making use of the motion of the spacecraft through the magnetic field of the planet. The electricity comes at the expense of orbital velocity. Ergo -- the more energy you pull from the tether, the more propellant needed to periodically reboost the orbit.<br /><br />This is the reason ED tethers are looking at being used in the *opposite* capacity to maintain the orbits of satellites and space stations orbiting Earth. Induce a current into an ED teher in lieu of drawing current, and it pushes against the magnetic field of the planet -- boosting the orbit of the satellite/station without the use of any propellant.<br />

 

[najab]

<blockquote><font class="small">In reply to:</font><hr /><p>Electrodynamic tethers produce energy by making use of the motion of the spacecraft through the magnetic field of the planet. The electricity comes at the expense of orbital velocity. Ergo -- the more energy you pull from the tether, the more propellant needed to periodically reboost the orbit.<p><hr /></p></p></blockquote>But how much current would you have to draw in order to lower the orbit of an entire moon?<br />

 

[mrmorris]

<font color="yellow">"But how much current would you have to draw in order to lower the orbit of an entire moon? <br />"</font><br /><br />Um -- I was assuming that his statement of :<br /><br /><font color="orange">"Speaking of which I am wondering outside of one proposal no real use of electro-teathers have been looked at for powering ultra high mission to jupiter."</font><br /><br />meant that he was talking about a JIMO-type 'high-power mission'. At any rate -- that's what my reply was about.

 

[najab]

Oops, my bad. <img src="/images/icons/blush.gif" />

 

[meteo]

30 days on Callisto is about the same as getting an average amount of medical examinations, and the natural sources of earth. A company could according to federal law pay people to work in these levels of radiation, I believe barring none of them was pregnant. I think that NASA's radiation requirements are acctually more stringent then the "general" regulaions.<br /><br />I'm searching for an average rem/day figure for the moon; not easy thanks to hoax pages and the band REM. <img src="/images/icons/smile.gif" /><br /><br />Here's solar flare risk though.<br />http://www.cru.uea.ac.uk/~mikes/moon/flare.htm<br /><br />

 

[liquidspace2k]

CalliArcale is this somewhat what your looking for...<br />It’s in the article that Meteo gave the link to..<br /><br />5 rem/yr, or 25 rem in a single emergency exposure: "maximum permissible dose" in terrestrial radiation workers <br /><br />25-100 rem: increased probability of leukemia; germ cell damage (likelihood of problems in offspring) <br /><br />100-250 rem: nausea/vomiting in hours; high incidence of leukemia; shortened life; can die if untreated <br /><br />250-750 rem: nausea/vomiting after about an hour; shock; death likely within 1 month if untreated; cancers; cataracts; significant life shortening; sterility <br /><br />750-2,000 rem: nausea/vomiting within an hour; unconsciousness then temporary return to conciousness; death within a week <br /><br /> />2,000 rem: unconscious in minutes; brief recovery then death <br /><br />10,000 rem: one instance documented. Death occurred in 38 hours.