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How Close Are We To a Mars Mission? (thenewstack.io)
destinyland writes: NASA is developing the capabilities needed to send humans to an asteroid by 2025 and Mars in the 2030s," reads the official NASA web site. But National Geographic points out that "the details haven't been announced, in large part because such a massive, long-term spending project would require the unlikely support of several successive U.S. presidents." And yet on November 4th, NASA put out a call for astronaut applications "in anticipation of returning human spaceflight launches to American soil, and in preparation for the agency's journey to Mars," and they're currently experimenting with growing food in space. And this week they not only ordered the first commercial mission to the International Space Station, but also quietly announced that they've now partnered with 22 private space companies.
All of that is vastly more impractical than the current minimalist Mars mission concepts. We can't scrounge up the funding for one of them, and you want to build something vastly larger?
Magnetic shields are good for preventing solar radiation but do little against GCR. You still need physical shielding sufficient to block GCR - which is harder to block anyway, aka, you still need significant shielding.
You - and TFA - mentioning growing crops is naive. The reason that all serious baseline approaches only call for small, experimental-level (rather than sustinance-level) crop growing is because A) that's way too much risk (starvation due to crop failure, which is tough enough to prevent here on Earth from thousands of different causes, yet alone in a radically different environment) to impose on an early mission, and B) shipping in the food to last for a typical mission duration is actually lighter than the cost of shipping in a facility large enough to grow that much food and the associated power and environmental systems required to operate it. The ability to grow crops would be important for long-term habitations (which is why NASA is researching it - although the plant growth experiment designed for the Mars 2020 lander got cut), but the first missions to Mars absolutely will not be relying on it for any relevant portion of their calories.
VASIMR is not new. One however does need to remember the downside: any high ISP /moderate to high thrust system is inherently going to be consuming vast amounts of power. And producing vast amounts of power means vast amounts of cooling area. So while it's "possible" to power a ship like this, it also means a very large ship... which partially eliminates the reason why one would want such a craft in the first place. It's more important for space "tugs"/"ferries" which take many trips, and for outer-planets missions. And note that there are many alternatives to VASIMR.
And please, you do a discredit to yourself by adding "or those EM drives".
Hello from Sputnik 2. I am receiving you.
I wish you were modded up because you are interesting, but you are oh so wrong.
Prions are scary because they don't seem to have a solution- like Ice-9 in Cat's Cradle, they convert everything that is like them, into them, until nothing is left. But, they require full biological access- you pretty much have to eat them in order for them to be permitted access to the things that are "mostly" like themselves. In many other places, the immune system would be able to stop them (for instance, cell membranes), because they would recognizably change the surface You couldn't ruin yourself by just inhaling a prion, like you could a virus.
A virus is probably more likely as a threat, and we (maybe) understand how unlikely it would be that a virus capable of infecting humans would be on Mars.
Your post also has an interesting implication- it implies that the "Great Filter" is that a terrible anti-life thing evolves faster than defenses for it can, in most situations. It hypothesizes (whether you did or not) that life on Mars both existed, and met its end at the end of some molecular grim reaper, that we risk contaminating Earth with. I would argue that such a Grim Reaper (molecule or construct) would have reached Earth at some point already- and if not, that we would likely find such a Grim Reaper on pretty much ANY planet we looked, and were just spared for no reason. This seems unlikely (but interesting).
Finally on the "Mars contaminates us" point, it is MUCH more likely that we find something inimical to human life here on Earth- for instance, very deep in an ocean, or near the top of a mountain, or buried in ice. Do you raise your FUD Flag against such a threat? Or is it only confined to space travel? Reminder: Our species will ultimately go extinct without space travel- this is a fact!
On your other point- "we contaminate Mars"- fucking fine. There's nothing amazing on Mars right now, life-wise, and if there is, we can keep it in a tiny Mars zoo. It's totally worthless to dedicate a whole planet to whatever random bacteria Mars happens to host right now, if indeed it hosts anything. A few score petri dishes will do nicely.
We could just hitch a ride on a comet that is flying close by both planets to avoid fuel costs and size of spacecraft limitations :)
At what relative velocity would you like your spacecraft to land on the comet?
I know that you are joking, but I've heard this idea proposed seriously more than once. This comment is for those people.
It is dangerous to be right when the government is wrong.
I'm a guy who stared up, glassy eyed (mostly because I was a kid in the middle of a serious sunstroke) as Armstrong stepped down that ladder, I had my plastic model of the Saturn V and scrapbook after scrapbook of the Apollo missions,so I guess you could call me a fan of exploration, science, engineering - all the things that had to come together for that moment to happen, but I honestly think those days are gone or at least disappearing. Two things end up driving exploration - a romantic ideal of the need to know, and the chance for someone to make a whack of cash. I think like after the "discovery" of North America, it's the investors that will drive the future of space. Nobody with any control over the sort of money this is going to cost believes that we are genuinely on the edge of destroying Earth - no "Interstellar scenario" is forthcoming - so what it will end up being is profit. Mining, most likely. As robotics advances the arguments are fewer and fewer for putting humans in harm's way. Maybe Mars will end up being on the list, my bet is the asteroid belt, though.
Temperature extremes, radiation, micro-meteorites (common to any space mission, I suppose). Needing to lift gear much further up than a 300~400 km low orbit. Actually succeeding in landing that gear undamaged. Gravity - but lower than on Earth. Redundant and/or extremely reliable life support systems, since Earth will be 'close' but still too far away for actual emergencies.
Not at all the same. Due to having an atmosphere, almost all those parameters are vastly different. The temperature extremes are not nearly as extreme on Mars, there is (slightly) less radiation, and almost no micro-meteorites. There is no 'landing' on Mars like with the moon, but rather EDL (Entry, Descent, Landing) as on Earth. That is actually much more difficult than landing on the moon: the atmosphere really isn't thick enough for parachuting a large mass, but too thick to light a retro rocket at high speed. I suspect that this is one of the reasons that SpaceX ignite a retrorocket on landing the Falcon 9 first stage: to practice doing so for a Mars mission. Also, Mars has twice the gravity of the moon, which will bear in ways that we don't know yet on astronaut's physiology.
Other than the "getting there" stage, Mars will be much easier to colonize than the moon. And the "getting there" challenges are surmountable with current technology, the "living there" challenges are much, much more difficult.
It is dangerous to be right when the government is wrong.