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.
Related Stories
One of the primary drivers for the distinct lack of a Martian atmosphere is believed to be the loss of atmospheric molecules that are stripped away by the passing solar wind. A strong planetary magnetic field would divert the solar wind around the planet and protect the Martian atmosphere. The MAVEN spacecraft confirmed this is happening, and some interesting ideas have been floated to mitigate the effect.
A recent paper published in JGR: Space Physics used Magnetohydrodynamic (MHD) models to investigate the magnitude of the effect on atmospheric retention that a magnetic field would have on Mars and found a very interesting result. Their models confirmed that the rate of atmospheric loss was six times higher for a planet with no magnetic field compared to a planet with a strong magnetic field; however, they found the highest rate of atmospheric loss was actually when there was a weak magnetic field.
But the highest rate of atmospheric ion loss was with a weak magnetic field—6 times faster than with no magnetic field at all. The team found the reason was the magnetic field lines, which guide the motion of charged particles, were easily blown back by the solar wind, creating a path for these ions to escape into space above Mars's nightside. This means that instead of providing a small measure of protection, Mars's remnant magnetic field could actually have sped the planet's transformation into the cold, barren world it is today.
Research Paper: Sakata, et al., Effects of an Intrinsic Magnetic Field on Ion Loss From Ancient Mars Based on Multispecies MHD Simulations, Journal of Geophysical Research: Space Physics, https://doi.org/10.1029/2019JA026945, 2020
(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.
(Score: 0) by Anonymous Coward on Friday March 17 2017, @11:21PM
First step to the realization Neo-Venezia.
(Score: 0) by Anonymous Coward on Friday March 17 2017, @11:30PM (6 children)
Venus has no magnetic field but has an atmosphere >90x thicker than earth...
(Score: 3, Interesting) by butthurt on Saturday March 18 2017, @12:25AM (5 children)
Yes, and Venus is a bit smaller and less massive than the Earth. Like Mars, most of its atmosphere consists of carbon dioxide (molecular mass 44 a.u.). The desire, I assume, is for water (14 a.u.) to remain. Venus is thought to have had much more water in the past, which was stripped away by the solar wind due in part to the weak magnetic field (the planet's somewhat weak gravity and its nearness to the Sun would also be factors).
(Score: 0) by Anonymous Coward on Saturday March 18 2017, @12:27AM (2 children)
Funny how all these planets have CO2 atmospheres and we freak out when our atmosphere gets a teenie tiny bit of CO2...
(Score: 2, Touché) by Anonymous Coward on Saturday March 18 2017, @12:30AM
This! We so want our atmosphere to be like Mars or Venus.
(Score: 3, Funny) by butthurt on Saturday March 18 2017, @12:39AM
Oh, absolutely. When some people freak out over a little puff of hydrogen, methane and hydrogen sulfide, I tell them it's just a recreation of the atmosphere of Jupiter.
(Score: 2) by butthurt on Saturday March 18 2017, @12:27AM
*correction, molecular mass of water is 18 atomic units not 14
(Score: 0) by Anonymous Coward on Saturday March 18 2017, @09:57AM
(Score: 4, Informative) by butthurt on Saturday March 18 2017, @01:20AM
A year ago, someone asked:
Instead of placing many magnetic satellites close to Mars to artificially generate a magnetic field to protect Martian colonists from harming radiation, we could place a magnetic satellite at Lagrangian point L1. The magnetic field does not need to be as strong to deflect the solar wind enough, since the deflection takes place over millions of km before reaching the planet. What would this require to be practical?
-- https://space.stackexchange.com/questions/14352/place-a-satellite-at-sun-mars-l1-to-shield-mars-from-sun-radiation [stackexchange.com]
Javascript is required to read the end of the discussion.
(Score: 3, Interesting) by jmorris on Saturday March 18 2017, @04:21AM (1 child)
Everything sounds great, Mars terraformed inside a realistic time frame, decades instead of the ten thousand year plan usually tossed around. But how big does that magnet have to be? A couple of Tesla? Are we talking about flying an MRI machine and a solar array or does it need to be a couple of Tesla on the surface of a ten kilometer sphere of solid superconducting unobtainium powered by a warp core?
I know one thing though, that would be one hell of a case of 'climate change' to touch off and no way I'd want to be on the surface to find out how many unexpected processes would try to kill me. I mean we haven't even walked on the danged planet and we want to introduce that kind of sudden drastic change? While the first people are establishing a foothold. I'd volunteer to do an initial survey mission but get me outta there before the magnet switches on.
(Score: 1) by khallow on Saturday March 18 2017, @01:35PM
I know one thing though, that would be one hell of a case of 'climate change' to touch off and no way I'd want to be on the surface to find out how many unexpected processes would try to kill me. I mean we haven't even walked on the danged planet and we want to introduce that kind of sudden drastic change? While the first people are establishing a foothold. I'd volunteer to do an initial survey mission but get me outta there before the magnet switches on.
Not seeing the problem myself. Just make sure your structures are engineered for the heavier atmosphere and such.