so, we have landed on and flown past many planets and yet, don't have much to show for anything but mars.
so i was realizing what with the failure of our last comet lander mission-------------why not bring back NUCLEAR BATTERIES instead of solar panels.
which then, made me realize one simple thing, the cold side of mercury is more than reasonable for a planetary lander to land on and then study.
more importantly, on the dark side, shielded from the suns intense rays, the lander would have to MOVE to avoid being roasted. fortunately a day on mercury lasts 1400 hours. and because mercurieis circumfrence is between 9400 and 9600 miles, this means a lander would have to average near 6.8 miles per hour at all times to stay in permenent darkness as the days past.
even while the lander takes breaks to study, a lander capable of doing 10-12 miles an hour ------powered by a nuclear battery, could keep itself warm and powered , with power for LED's and other electronics.
the best part of this mission is that the lander could dig up things and then come back to them after they've been roasted 'overday' when the nighttime falls again. in this vain, the lander could actually study the effects of mercurian sunshine on newly exposed mercurian soil.-- teslaberry, Feb 02 2015 existing missions to mercury http://en.wikipedia...Observation_history [teslaberry, Feb 02 2015] 24/7 solar power Lunar_20Rail_20Dist...ed_20Infrastructure [FlyingToaster, Feb 03 2015] Mercury orbit/rotation http://sciencenetli.../OrbitRotation.html [tatterdemalion, Feb 03 2015] Mercury 2.0 Mercury_202_2e0_20(the_20planet)This baker got very enthusiastic about the prospect. Right down to the username. [bungston, Feb 03 2015] I don't think most nuclear batteries have enough power output to move themselves around at 7mph. And if the rover gets behind and gets caught in the daylight, I think the 427 deg C temperatures are likely to kill a lot of your electronics.
If you land near one of the pole, it's quite cold (-93 C) day long, so there ought to be someplace just a bit closer to the equator that has usable temperatures during the day, and survivably cold nights. Your unconventional idea of circumnavigating the planet to maintain the proper temperature would be much more doable at a high latitude as well.-- scad mientist, Feb 02 2015 Nice idea, but on the other hand, if there ever was a planet where solar power packs some punch, it would be Mercury.-- AusCan531, Feb 02 2015 Shielding a lander from IR and visible radiation can be done surprisingly effectively using a clever bit of technology called a" mirror".
If the vehicle is close to the terminator, as the sun rises it can harvest enough solar energy via PV panels to scuttle back into the shadows - essentially a robotic cockroach.
Besides, Mercury's a dump. You've been to your moon? Well, Mercury's about the same, just a bit more gravity.-- 8th of 7, Feb 02 2015 // Besides, Mercury's a dump
Yeah, no night-life...-- Ling, Feb 03 2015 No atmosphere either.-- AusCan531, Feb 03 2015 This idea would be half-baked until it fails.-- lurch, Feb 03 2015 A mirror could keep out the direct sunlight, but when you have 88 days of continuous heat, the ground nearby is going to heat up, and it is going to conduct to the ground under the mirrors and through the wheels of the rover. You may have some pretty good insulation to slow down the conduction, but it won't keep it cool that long.
Although... is there a photo-voltaic technology that can withstand that heat? If so, maybe you could use a heat pump to keep critical components cool while using mirrors and insulation to reduce the load on the heat pump, but you'd need a very good heat pump to handle that temperature difference.-- scad mientist, Feb 03 2015 //unconventional idea of circumnavigating
Actually that one has cropped up in an SF story, can't remember exactly, but possibly some power-station on tracks on the moon, perpetually in sunlight...-- not_morrison_rm, Feb 03 2015 //SF story// An HB post, mine in fact :) I wrote and rewrote and deleted and reposted ... and it still looks like crap, but the idea's there <link>.
[edit: and another one: "Terminator Lunar Colony" by [simonj] ]-- FlyingToaster, Feb 03 2015 Mercury is not actually tide-locked to the Sun; most places on its surface experiences a day/night cycle. Only at the poles can you find places (craters) that might be permanently in shadow.-- Vernon, Feb 03 2015 // why not bring back NUCLEAR BATTERIES instead of solar panels.
Bring back? They never stopped using them. Radioisotope thermoelectric generators are onboard Mars Curiousity and the New Horizons Pluto probe.
[Vernon] Mercury is gravitationally locked in a sort of 3:2 orbit/rotation ratio. As such a Mercury day is about two Mercury years long. [edit: this is wrong, see correction below]. So all surfaces except extreme polar regions face the sun over the course of that time.-- tatterdemalion, Feb 03 2015 You vastly overestimate the technological feasibility of a rover capable of going around Mercury-- Voice, Feb 03 2015 It doesn't have to be autonomous.
Satellite mapping will allow a route to be pre-planned. Combined with feedback imagery from the rover, navigation won't be too difficult, providing a viable route exists.-- 8th of 7, Feb 03 2015 //Radioisotope thermoelectric generators are onboard Mars Curiousity and the New Horizons Pluto probe//
Wot he said. Solar panels are super cheap and light if you consider how much energy you can get out of them on the scale of years. Especially when you don't put a whole lot of atmosphere in the way.
// Mercury is gravitationally locked in a sort of 3:2 orbit/rotation ratio.//
May I suggest Sturmey archer as the prime sponsor...?-- bs0u0155, Feb 03 2015 Could possibly land in the dark and have enough time to dig a hole to hide from the sun when needed. Do your exploring in the dark.-- cudgel, Feb 03 2015 My take on this was to use nukes to generate wave amplification retarding rotation to the point where Mercury becomes tidally locked. Mine half the planet in the shade, then flip it around again and mine the other half.-- 2 fries shy of a happy meal, Feb 04 2015 How will a shock wave stop the planet's spin?-- Voice, Feb 04 2015 Only way to find out is to try it.-- pocmloc, Feb 04 2015 Now I have a nagging suspicion [8/7] will stop Mercury's rotation and actually nudge it out of orbit, colliding it with Earth on a fine Sunday morning.
He will be standing in your front yard, reciting horrible poetry, when it occurs.-- UnaBubba, Feb 04 2015 //How will a shock wave stop the planet's spin?//
Not 'a' shock wave, many directional shock waves timed to amplify, and we don't need to stop the planet's spin... just tilt one of its poles to face the sun. Maybe tidally locked is not the right term for this.
Given a large enough 'lever' located close enough to the center of the planet we could rotate a planet's poles within a single revolution. I call it gyroscillation.-- 2 fries shy of a happy meal, Feb 04 2015 // why not bring back NUCLEAR BATTERIES instead of solar panels.
They never left; many space missions use them right now. The reason that Philae didn't use one is entirely down to ESA politics (and scarcity of the plutonium isotope that RTGs use)-- Hive_Mind, Feb 04 2015 // a Mercury day is about two Mercury years long.
Self-correction - I got the math wrong on that 3:2 thing. It's actually a Mercury year lasts a Mercury day and a half.-- tatterdemalion, Feb 05 2015 // Now I have a nagging suspicion [8/7] will stop Mercury's rotation and actually nudge it out of orbit, colliding it with Earth on a fine Sunday morning. //
Not us. Q might do that, but not us. You humans are far too good entertainment to kill you all off.
Yet.
// He will be standing in your front yard, reciting horrible poetry, when it occurs. //
Don't diss our poetry, man.
// scarcity of the plutonium isotope //
= reluctance to bow the knee to the Yanks or the Ivans.-- 8th of 7, Feb 05 2015 //Self-correction - I got the math wrong on that 3:2 thing. It's actually a Mercury year lasts a Mercury day and a half.//
No, you were right the first time. Mercury completes three full revolutions (with respect to an outside observer standing above the ecliptic) every two (Mercury) years. However it's also completing two full orbits every two years, which subtracts from that count. Therefore it only gains one full revolution every two years. So it's day is 176 (earth) days long, and it's year is 88.-- MechE, Feb 05 2015 Now I'm confused, and it sounds like you're agreeing with me.
According to the diagram I linked, it appears Mercury does one full rotation on its axis in about 58 earth days, about two-thirds of a Mercury year.
But that doesn't mean every point on the surface has been exposed to the sun. Seems like it takes about one and a third solar orbits for that to occur. I guess that's the only factor relevant to this idea.
I think you're right [MechE] but I'm not sure I'm wrong, I probably am. I was right once though.
(Just did some checking and it seems the 58-and-change earth days per Mercury day is correct, not 176.)-- tatterdemalion, Feb 05 2015 Nope. It's definitely 176. The key thing here is that a full rotation of the planet (your 58.6 days) is not a full day. Mercury rotates on it's axis 1/2 way over 1/3 of it's orbit. But since the two are in the same direction, only 1/6th of the planet is newly exposed to sunlight (the orbit subtracts from the rotation).
This is the same reason why the same side of the moon always faces us. It rotates 1 full rotation in 1 full orbit, and when you subtract the two, you get zero relative change to the earth.
In order for the same meridian on Mercury to reach the same position relative to the sun ( a full day), Mercury must make 6/3rds of an orbit, or two complete orbits.
Look at your own link and see how many complete orbits it takes before the one and the two are in the same orientation relative to the sun (NOT the screen, which does happen at the 2/3 point).-- MechE, Feb 05 2015 I think the confusion stems from what definition of "day" we're using.
I'm referring to a complete rotation around its own axis, a sidereal day, which for Mercury is ~58 earth days. I think you're talking about a solar day, a complete rotation relative to the sun - which granted is a mess to figure out for Mercury, but is indeed 176 earth days.
But yes, the solar day is really the number we're looking for here, as regards the idea.-- tatterdemalion, Feb 05 2015 <at the post office>I'd like to send this parcel to Norfolk, how many days do you think it will take? <clerk>Solar days or sidereal days sir?-- pocmloc, Feb 06 2015 Yeah, day means solar day. Sidereal days only exist because the astronomers were to lazy to make up their own word.-- MechE, Feb 06 2015 // I'd like to send this parcel to Norfolk, how many days do you think it will take? //
You have to allow for the time difference - when it's 1200 hrs GMT in London, it's only 1156AD in Norfolk ...-- 8th of 7, Feb 06 2015 random, halfbakery