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https://m.phys.org/news/2017-03-nasa-magnetic-shield-mars-atmosphere.html
In essence, they suggested that by positioning a magnetic dipole shield at the Mars L1 Lagrange Point, an artificial magnetosphere could be formed that would encompass the entire planet, thus shielding it from solar wind and radiation.
[...] In addition, the positioning of this magnetic shield would ensure that the two regions where most of Mars' atmosphere is lost would be shielded
[...] As a result, Mars atmosphere would naturally thicken over time, which lead to many new possibilities for human exploration and colonization. According to Green and his colleagues, these would include an average increase of about 4 °C (~7 °F), which would be enough to melt the carbon dioxide ice in the northern polar ice cap. This would trigger a greenhouse effect, warming the atmosphere further and causing the water ice in the polar caps to melt.
Pretty SF but I enjoyed the article.
(Score: 0) by Anonymous Coward on Friday March 17 2017, @11:16PM (10 children)
And this device will be powered by unicorn farts and faerey dust
(Score: 2) by bob_super on Friday March 17 2017, @11:34PM (2 children)
But I expect easy financing for the Bruce Willis movie where he will repair the shield at the last second, sacrificing himself to save his daughter and grandchildren on Mars.
As long as nobody objects that diverting Phobos to L1 (after the primary mission fails because the bad guy wants to Make Earth Great Again) would require a lot longer than the Red Deadline Clock would allow, I've got most of the scenario already wrapped up.
(Score: 1) by Ethanol-fueled on Saturday March 18 2017, @12:18AM (1 child)
This is more related to Total Recall and if there are three-boobed women [blogspot.com] there, so am I.
(Score: 2) by c0lo on Saturday March 18 2017, @06:00AM
At least Johnny Cab seems to be on track for market.
https://www.youtube.com/watch?v=aoFiw2jMy-0 https://soylentnews.org/~MichaelDavidCrawford
(Score: 2) by butthurt on Saturday March 18 2017, @01:14AM (3 children)
The slide doesn't show it, but particles from the solar wind would, I expect, impinge upon the craft, much as they migrate along the lines of the Earth's magnetic field to form the aurora australis and aurora borealis. Perhaps their energy could be harvested.
If a steady magnetic field were generated, rather than a fluctuating one (why would one do that?) the amount of energy needed to maintain the magnetic field could be modest or even nil. I hope you're familiar with neodymium-iron-boron magnets. They retain their magnetic field without continuing input of energy.
https://en.wikipedia.org/wiki/Neodymium_magnet [wikipedia.org]
A superconducting magnet must be kept cold, but requires electrical energy mainly when it's initially energised:
An alternate operating mode used by most superconducting magnets is to short-circuit the windings with a piece of superconductor once the magnet has been energized. The windings become a closed superconducting loop, the power supply can be turned off, and persistent currents will flow for months, preserving the magnetic field. The advantage of this persistent mode is that stability of the magnetic field is better than is achievable with the best power supplies, and no energy is needed to power the windings.
-- https://en.wikipedia.org/wiki/Superconducting_magnet#Persistent_mode [wikipedia.org]
Linked from the article is another article called "European team announces superconductivity breakthrough."
Of course some energy would be needed for station-keeping. Someone wrote in Wikipedia without a citiation:
Any object orbiting at L1, L2, or L3 will tend to fall out of orbit; it is therefore rare to find natural objects there, and spacecraft inhabiting these areas must employ station keeping in order to maintain their position.
-- https://en.wikipedia.org/wiki/Lagrange_point [wikipedia.org]
It seems to be correct with regard to L1--see the remark at the end of page six of this paper.
http://www.engr.uconn.edu/~cassenti/Astrodynamics/L1Mars-AIAA-2010-6577.pdf [uconn.edu]
(Score: 0) by Anonymous Coward on Saturday March 18 2017, @11:15AM (2 children)
You want to harvest energy from the particles you are repelling? Well that's easy, all you need is a perpetual motion device.
(Score: 3, Insightful) by maxwell demon on Saturday March 18 2017, @11:49AM
No, you don't need a PM. The device only needs to work as long as the sun provides a steady stream of charged particles. As soon as this influx of particles drops, youi'll certainly lose your energy source, but you'll also lose the problem which that satellite is made to solve (not that you wouldn't have to fight a lot of other problems in that case, but that specific satellite would no longer be required).
The Tao of math: The numbers you can count are not the real numbers.
(Score: 2) by butthurt on Sunday March 19 2017, @02:14AM
> [...] all you need is a perpetual motion device.
I assumed readers were familiar with what I called "the aurora australis and aurora borealis." These are lights in the sky at high latitudes that are caused by, as I said, particles from the solar wind following the lines of the Earth's magnetic field and ionising atmospheric gas.
https://en.wikipedia.org/wiki/Aurora [wikipedia.org]
The proposed satellite wouldn't have an atmosphere, so I would expect, as I said, some of the particles to strike it. It's those particles from which, I imagine, energy could be gathered. I didn't propose trying to collect energy from the particles that are deflected, although that would in theory be possible. There's a phenomenon called bremsstrahlung: when a charged particle is deflected or slowed, it emits radiation. Since the deflection would happen within a huge volume of space, the bremsstrahlung would be spatially diffuse and probably not worth trying to collect. It's not a matter of perpetual motion, however.
https://www.britannica.com/science/bremsstrahlung [britannica.com]
The particles that strike the magnetic poles of the satellite would give up their energy in a much smaller space. Making use of it might be worthwhile.
(Score: 2) by Scruffy Beard 2 on Saturday March 18 2017, @05:33AM (2 children)
A large enough Radioisotope thermoelectric generator [wikipedia.org] would probably work.
(Score: 2) by Scruffy Beard 2 on Saturday March 18 2017, @06:00AM (1 child)
On second thought, that may be 2 orders of magnitude short.
Apparently the Voyager RTG's were ~400W.
Random doc it found [cocir.org] is talking about MRI machines using ~20kW in stand-by mode, or ~10kW in "off" mode.
This page [fonar.com] is talking 60kW for the magnet (I assume all the processing equipment would not be needed).
(Score: 3, Insightful) by maxwell demon on Saturday March 18 2017, @11:54AM
How much of that energy is used for fighting the influx of atmospheric heat?
The Tao of math: The numbers you can count are not the real numbers.