Quora: Is 2025 the Soonest We Can Get to Mars?

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Answer from Nicolas Nelson, advocate for human space development:

Original question: Why do we have to wait till the year 2025 to go to Mars? Is the necessary technology not developed yet? Are we waiting till Mars gets closer to us? 

You've tangled three questions into one, here, and although they are related, it may help to answer them one at a time. Beginning with your last one:

  • Mars and Earth are in “opposition” (which ironically means “at their closest point to one another”… Why? That's a separate Answer!) roughly every 26 months. We don't need to wait until 2024 or 2025 to go to Mars, but that happens to be one of the windows of opportunity. The soonest launch window to Mars is coming up next year, 2018. Remember, though, the Hohmann Transfer Orbit (the least-energy and wisest trajectory for humans to take from Earth to Mars: Google it) takes a good six months to go from Earth to Mars. A higher-energy trajectory could get you there quicker, but would be much riskier. That's why we speak of Mars voyages happening at a certain year, not a month or a day (though the exact launch date and even launch time window will be calculated for each mission, once all the other mission details get hammered out).

Note that once you arrive at Mars you'll only have a couple of weeks before you'd have to begin a fresh Hohmann transfer back to Earth, otherwise you'll have to hang out on Mars for about 18 months before another launch window comes around, to return to Earth! That's why human missions to Mars are either short term (ten days or so on the planet) or long term (two years on the planet). You can't get bored or run out of food, etc. and just go home to Earth after four or five months on Mars. If you stayed that long, you're stuck there till the next “opposition” comes around.

  • “Is the necessary technology not developed yet?” *deep breath* …This is a sensitive topic for real Mars scientists and mission planners. In one sense, we've had the technological capability to send humans to Mars since 1997. We have known about the Martian surface and atmospheric conditions, we’ve photographic maps of the entire planet, we've proven human spaceflight in cislunar space outside the protection of Earth’s magnetosphere. We understood everything necessary to build the equipment and fly the equipment and the human explorers in it all the way to Mars and back. However, technological capability is not the same as having the tech itself. We have not yet actually built the Mars rover the first Mars explorers will use when they travel to Mars. Not because we don't know how, or don't possess the materials or tooling to manufacture it— just because we haven't decided exactly what sort of rover it ought to be. In one sense, we know too many ways to build perfectly useful, durable, powerful Mars rovers, and one particular design hasn't been decided upon yet. Or if a certain Mars mission plan does specify a particular, detailed, fully-developed design, that mission hasn't been funded and scheduled, so work has not begun on that rover.

The same can be said for the Mars spacesuits (or “field suits” since they will be rugged for use on Mars’ rocky surface), the “reverse water/gas system” (RWGS), the Sabatier reactors, the “tuna can” habitat they’ll live in, or even the Earth Return Vehicle to bring them home (it was going to be a two-stage Orion capsule, then maybe a two-stage Dragon capsule, now neither option seems to be a sure thing anymore). Everybody develops awesome “proof-of-concept” gear but none of it is really “in production” because pesky preliminary details keep getting in the way.

Mars The planet Mars showing showing Terra Meridiani is seen in an undated NASA image. NASA will be sampling soil from the Martian surface. Reuters Pictures

“Details” like space infrastructure, for example. Humanity has dragged its collective feet for so long now, we’ll need to build and send at least one fresh Mars Global Surveyor or Mars Observer-class satellite before our first human mission, to provide a navigational aid on approach to Mars orbit, and to serve as a communication-relay satellite between the Mars expedition and Earth, not to mention any other support services it might provide to the Mars expedition on the surface. The current satellites orbiting Mars now could have served those roles, but they are getting old, and need to be replaced!

  • “Why do we have to wait till the year 2025?” Hey, that's not waiting, that's hurrying! Because of all I've said, we have a ton of work to do— not inventing brand-new stuff, but building stuff we know already how to build, or know how to learn how to build, if you see what I mean. If humans land on Mars in 2025/2026, that qualifies as “full speed ahead” and means we got serious about this right now, this summer and fall of 2017.

You’ll hear people say “we don't know how to survive long interplanetary space flights”, and “we need to develop this or that technology.” What they want to develop is a more efficient technology to solve the problems of propulsion, communication, or the toughest one, life support (air, water, food, sanitation, radiation shielding, zero-G amelioration). But we already have “brute-force” solutions to those problems that just don't seem very elegant: like, if water reclamation is a problem, just bring so much water that you won't need to reclaim hardly any of it. Haul along a 2-year supply of food, even if it’s MRE’s and bulk granola, as long as it keeps the astronauts alive. Use a tether to attach your spacecraft to the spent booster rocket that put you on your Hohmann trajectory, and spin up to nearly Earth-normal centripetal gravity (which, if the tether fails en route, only imparts 9 meters per second of delta-v to perturb your trajectory, in whatever direction— once you stabilize your craft’s orientation, that's an easy and low-delta-v correction to make). Food and water turn out to be excellent radiation shielding if you bring that much along with you and store it along the outer walls of your craft. We don't need the VASIMIR drive or giant pinwheel cruisers or Unobtainium cosmic ray armour or bone-regeneration nanotech to start visiting and exploring and even settling Mars.

We do need to get specific, fund that specific expedition, build that specific gear with the technological capabilities we have now, and get going.

Honestly you guys, our mothers and fathers could have gone to Mars in the 1990s and early 2000s with the capabilities they had then. We can go now, arriving in the 2020s. Or we can abdicate too, and hope our grandchildren will find the will to go with the capabilities they will have. It won't ever be easy or simple.

But it's never been as easy as it is right now. And the choice not to try does not lay a strong foundation for the generations that will follow us.

Why do we have to wait till the year 2025 to go to Mars? originally appeared on Quora - the place to gain and share knowledge, empowering people to learn from others and better understand the world. You can follow Quora on Twitter, Facebook, and Google+. More questions:

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