A Conversation With Robert Zubrin

To get to Mars first we have to get to Phobos as fast as possible as absolute speed lessens the human exposure to interstellar radiation, especially solar flares that are unpredictable when starting out on the journey. Also our consumption of consumables will be much less, meaning we don't have to take so much with us.

So, let's go fast. Instead of a leisurely 12 month or more journey from Earth to the vicinity of Mars that mostly involves coasting after an initial acceleration, let's accelerate the whole way, using every speed booster we can think of, from solar sail to ion engine. If we could cut the trip to three months one-way, we dramatically make the mission easier to manage. Some dangers would be increased, but many would be dramatically decreased by the shortening of transit time.

Then, when we near Phobos, let's use it as our emergency brake--i.e. a large mass that we reach out and grab or snag to slow ourselves down. Some type of pre-positioned structure would greatly aid in this. In a patent (pending) I have suggested a simple lasso of high tech carbon fiber, but other ideas have been suggested that might work as well, including elaborate tight beam projectors to slow an approaching spacecraft.

The important thing is that speed is wonderful. Also acceleration, because human beings really like the feeling of gravity. It is good for us. Once we get down to the surface of Mars we will experience a little gravity, but it would still be a good idea to exercise every day in a full 1-g centrifuge.

I dream of going to/living on/recreating on Mars. This is a life long dream that I certainly hope will soon be a reality. Thank you POPSCI for this interesting and great article. For more on Mars recreation see www.ootwo.com and go to any of the Mars pages, I think there are 3 or four. Plus in the blog section there are some fun articles as well.

I just read this book (found it on the shelf at Borders yesterday, despite the release date cited) - it's hard to describe since it's actually serious on several levels (sci-tech, social-political, philosophical even) but just a hoot all around. HIGHLY recommended.

Mr. Cook I have to say your plan is pretty far-fetched. Number one, carrying fuel for constant ignition would be stupidly heavy, and would never even get off the ground just from the shear weight of it. Also, Phobos is a horribly irregularly shaped moon, and is more of a large asteroid than a moon, and hooking some lasso catcher's mitt to it is pretty out there. Let's say we could ship out some robots to phobos that could hook it up. Let's even say that it works, and that it could catch a spacecraft, that has been constantly accelerating in a frictionless environment for three months, the force behind this craft would be so immense, one of three things would happen:

1. the tension on the high tech rubber band would snap, flinging the spacecraft and crew off at a completely unpredictable trajectory, pretty much ensuring their death.

2. the band would hold, but the elasticity of it after extreme tension would just hurl it back the way it came, ensuring their death as well.

3. the band would hold, but the G forces behind so much acceleration would smash the craft like a soda can with a sledgehammer.

Not to mention how small phobos really is, at only 22.2km in diameter (a 15 minute drive) such a tug from something traveling so fast would throw off ITS trajectory as well, potentially causing the moon's destruction into Mars or just really screwing with its orbit, which is something its handling just fine on its own. We're already destroying most of our planet, i don't want to start solar system exploration with such irresponsibility as well.

I believe we should take small steps first. Colonizing Mars would be a very ambitious project indeed. I believe that we should try to colonize the moon first, then from there if everything turns out well we could turn to colonizing Mars or one of its moons Deimos or Phobos.

I know that it would be difficult for us to colonize the Moon but we have to start there first and there will be mistakes because we do not know every scenario that might take place even though we try to anticipate everything but there are some things that might be overlooked then once we have encountered them, then we might have a better understanding of how to colonize Mars. Besides, it would take a lot of resources like fuel for the trip to Mars - and the Moon is relatively nearer to us.

Maybe build something like a biosphere in the Moon first or make it habitable and then Mars...

Mr. Cook must be talking of a future when we'll have
a reusable Endeavour with an ion engine that half way to Mars does a 180 spin to reduce its speed. I was thinking that by having such ship we could use it to play billiards with comets and meteorites by using nukes to bombard Mars
to accelerate its terraforming, I saw something like
this in the Discovery channel. Well, I was wondering what would happen to Mars after colliding with something big and filled with water like Europa the moon of Jupiter, would it become more like the earth?

Hi Brpagel: Thanks for the technical analysis--which forces my brain up to speed after a dull shift at the day job. I didn't say anything about taking chemical fuel to burn on a constant acceleration to Mars. I said ion engine, which gives about double the fuel mileage. Also, the faster you go, the smaller you can make the spaceship, because you need to carry along fewer supplies.

Perhaps the best solution would be a focused beam propulsion system. Others have proposed building the base station on our Luna with a huge nuclear power plant, which would basically project a tight but humungous amount of laser energy at a heat shield/mirror on the departing end of the spaceship. This would give a constant push. If enough power is available to provide even a .5 g acceleration that would soon amount to a very high velocity. Then another beam projector on Phobos begins a .5 deceleration of the spaceship. The final step will be actually putting out high tensile strength ropes which would stretch to aid deceleration, with strain gauges monitoring to let out more cable if necessary to prevent snapping. Then you winch the spaceship in to Phobos (or the moon of any planet to which you may want to go at a high rate of speed.)

The fate of Phobos ultimately is to fall into Mars anyhow, as other Mars moons have done. Our techniques will actually delay that because we are adding energy to Phobos, not taking it away. Over repeated launches and recoveries of spacecraft we can calculate things so as to prevent the orbit of Phobos from becoming too eccentric.

Hello Mr. Mike Cook, you're proposing that the ship would travel at 5 Gs for it to reach its destination of Phobos early.

But, how long will that 5 G acceleration be? Coz if it would be months I don't think that humans could withstand that amount of Gs for a very long time. Or could they, I'm thinking that maybe they have to decelerate or stop everytime they have to eat, sleep or eat, am I right?

Besides the focused light beam propulsion that you've proposed... is there something like that in existence right now. And if so, wouldn't there be attenuation of the amplified power due to the distance involved? Sorry am grasping at straws here coz am not knowledgable about propulsion systems and other stuff. But, are my ideas valid or not?

Having read Robert Zubrin's "The Case for Mars" and "Entering Space", I was deeply impressed with his no-nonsense approach to getting a human presence on Mars as simply, cheaply and safely as possible. He emphasises the goal of Martian settlement as an extension of the human imperative to expand our territory and continue to push back our frontiers.

I couldn't agree more, but one thing I don't remember him mentioning is this: When we have another large impactor like the Chixalub meteor that ended the dinosaurs' reign, our fragile species will be extinguished if we have all our eggs in this one planetary basket.
Mars is our best local candidate for a backup. If we have a self-sustaining and genetically diverse community established when he Big One hits Earth, we can re-seed Mama or simply continue outward, carrying the essence and accumulated knowledge of humanity. Life will continue in the cracks and crevices of Earth, but not our life.
Thus shall the meek truly inherit the Earth.
I only hope that President Obama can see the wisdom in making Mars Direct happen before the end of his term.