Make Mars Magnetic Again !
Without a magnetic field, a lethal array of charged particles from the Sun bombards Mars’ surface every day threatening the potential of hosting electronic systems as well as biological life. The lack of a magnetic field also makes it impossible for Mars to retain an atmosphere or an ozone layer, which are detrimental in filtering out UV and high energy light. This would seem to make the basic principles behind terraforming the planet completely obsolete.
By placing a satellite equipped with technology to produce a powerful magnetic field at Mars L1 (a far orbit around Mars where gravity from the Sun balances gravity from Mars, so that the satellite always remains between Mars and the Sun), we could encompass Mars in the resulting magnetic sheath...
Some things to note are the exceptionally low voltage for the system of about 2 volts, and the dimensions/mass of the copper solenoid which come out to a torus with a total diameter of ~3.5 meters and a mass of ~57 tonnes. This is a big copper doughnut. It would fill the average living room area wall-to-wall and weigh more than 6x the legal mass of a loaded semi truck on the freeway. A magnetic field of ~81 Teslas is generated at the surface of the solenoid; nearly twice the strength of the strongest artificial continuous magnetic field ever produced to date. Another thing to note is the fact that a fission reactor of this size will require over 40 tonnes of uranium every two years to remain in operation. This may be the biggest problem for any future Martian-magnetosphere endeavor, seeing as a launch to Mars from Earth takes about 18 months and the abundance of uranium on Mars itself is unknown.
The total mass of the craft is about 317 tonnes. This would require 3 separate launches to Mars L1 from SpaceX’s proposed BFR, which Musk boasts will be operational by the mid 2020's. It is interesting to note that the fission reactor and the copper solenoid account for more than 50% of the spacecraft’s mass.
https://medium.com/@brandonweigel/an-artificial-martian-magnetosphere-fd3803ea600c
The biggest surprise for me is that the reactor would need to be replenished so often.
ReplyDeleteDavid Lazarus The craft is creating an 81-tesla magnetic bubble. That's a lot of magnetic energy. The Earth's own magnetic field is in the microtesla range. So I'm honestly not surprised to hear this.
ReplyDeleteWhy would one launch uranium from Earth? That seems kind of idiotic, given the gravitational wells in question and the obvious safety concerns of exploding rockets.
ReplyDeleteThis seems like a near-perfect application for asteroid-mining, at least in the mid- to longer term. Yes, one needs to find an appropriate target, and yes, one needs to set up a mining and refining operation...but if you can't do that, you have no business trying to do even more complicated things on Mars.
Is terraforming without generating a magetosphere really impossible? Was that one of Robert Zubrin's requirements? Not that I recall. https://www.universetoday.com/9730/zubrin-on-terraforming-mars/
ReplyDeleteuniversetoday.com - Zubrin on Terraforming Mars - Universe Today
David Lazarus It's not impossible, just fleeting. You need the magnetosphere because otherwise, the solar wind will blast the Martian air to space. So if you want Mars to have vaguely Earthlike conditions for more than a few thousand years, you need to protect that atmosphere. I imagine some might think a Martian colony is only a stepping stone of sorts as we migrate further from Earth, and might dismiss the need for such shielding. But if we're going to spend immense wealth and energy to making Mars green and pleasant, I figure we may as well protect and nurture it. (Which I wish we did with THIS planet, too, for whatever it's worth.)
ReplyDeleteLilith Dawn - Why do you think Zubrin does not consider an important component? I don't think he views Mars as a mere "stepping stone".
ReplyDeleteDavid Lazarus I can't talk for Zubrin at all. I did say, "I imagine some think." Just to be clear.
ReplyDeleteI suspect those who don't bring up the need for a magnetosphere either don't realize why it's important, or think it's irrelevant for one or more reasons. But the logic seems straightforward. Either you want the atmosphere to last for as long as humans (or our descendents) are willing to stay in the system, or you don't.
Actually, I do recall an argument -- not sure if it's Zubrin's, will have to research later -- that you may as well replenish the atmosphere as you go rather than shielding it to keep it from blowing away.
ReplyDeleteWhich I admit is valid, as long as you presume we have no better use for the asteroids, comets, and possibly moons we'd have to tap to give Mars a constant supply of air and water.
Nonetheless, I still think it's very short-sighted. For one, while industry might be able to scale up water/air production from extra-Martian resources, it's expensive to do so, and the only benefit is that you might not need domes and EVA suits as much. That might turn out to be cost-effective once Mars has millions of humans on it, but probably not before. You may as well protect your initial investment, I figure.
I also recall Zubrin specifically stating that you don't need full Earth air pressure to make Mars viable for human life, which is technically true as long as you opt for a very oxygen-rich environment. I don't know what the environmental impact would be beyond that, however, and I have a sneaking suspicion that chemical processes on Mars might make quick work of ambient oxygen. Also, oxygen counters the greenhouse effect, and so might slow down or reverse any attempt to warm the planet enough for constantly liquid water.
Kim Stanley Robinson's R/G/B Mars trilogy went with the replenish approach, but I suspect only because he didn't think of the super-magnet. (He did put a large mirror/lens device at L1 to boost insolation.)
ReplyDeleteIt's an impressive piece of speculative, hard science fiction--dense but well worth the time if terraforming Mars is an interest.