Obviously, any manned mission to Mars would be expensive. Probably REALLY expensive. Still, if the budget weren’t an issue, could we do it with off-the-shelf (or similar) components, like the Space Shuttle-derived ship they sent out to nuke the meteor in the movie Deep Impact? Could we pretty easily design a ship that would take the crew there and back, knowing what we do today?
Put another way, what additional technological advances or scientific discoveries, if any, do we still need to make before we can send a ship to Mars?
A recent issue of Discover (or was it Scientific American?) indicated that the radiation levels in interplanetary space constitute much more of an obstacle to manned missions than previously thought. The amount of shielding required would make it pretty much impossible to do.
Yes, I’ve read a lot about the loss of bone strength over extended periods in microgravity. I guess I always assumed there’d be something like (if you’ll pardon another movie reference) the centrifuge-created artificial gravity of the USS Discovery from “2001: A Space Odyssey.”
I’ve read varying things about the risk from cosmic radiation and solar flares. One NASA expert wrote several years ago that a few inches (or was it feet?) of water tankage around the crew compartments would be sufficient protection. Overly optimistic, perhaps?
Fortunately, the worst of the radiation is in charged particles, for which you don’t even need material shielding. A strong magnetic field will do. It might still be heavier than you’d like (everything on a spaceship is heavier than you’d like), but it’s better than a few meters of lead or whatnot.
Why? Most of the trip is going to be ballistic, and it’s not at all hard to build structures which can stand up to 1 g (or a fraction of a g; we don’t know how much is needed to prevent bone loss, etc.). Just have two modules (say, one containing the the crew compartment and life support, and the other containing fuel and equipment), and tie them together with a strong cable. Despin and rigidly couple the components for burns, and separarte them and put the spin back on for the months in Hohmann orbit.
Considering the technology existed for a manned Mars mission in the 1960s, it obviously also exists today. It’s just a matter of money and how you define “off the shelf”.
No the Space Shuttle cannot go to Mars, nor even the moon. It doesn’t remotely have the performance, plus all its systems – life support, power, etc – are not designed for a long duration deep space mission.
It requires a lot of mass in earth orbit to reach Mars. One baseline number was 614 metric tons (1.35 million lbs) of the 1960 Nasa Lewis study: http://www.astronautix.com/craft/mars1960.htm That would require the equivalent of five Saturn V launches or 27 shuttle launches just to lift the payload to orbit for assembly. That doesn’t mean you must resurrect the Saturn V, only that it’s a big job. Newer heavy-lift launchers could be developed during the design of the remaining crew vehicles and mission components.
Also, growth version of the Atlas V and Delta IV family have been studied which could loft approximately Saturn V-class payloads. So the booster technology exists or could be refined over the timeframe necessary for planning/designing other mission elements.
Several of the above Mars expedition plans envisioned using centrifugal-force artificial gravity. There are various methods to achieve this. It’s just an engineering problem and is not insurmountable.
The space radiation issue is serious and seems to get worse each time it’s studied more closely. Over the long duration of a Mars mission, you must plan on an intense solar flare, which outputs tremendous radiation. Aside from solar radiation, cosmic radiation is particularly difficult to shield against.
The March 2006 Scientific American article covered specifically cosmic (not solar) radiation risks. It concluded the only certain shielding method currently available is a spherical shell of water five meters (16.4 feet) thick. For a small crew compartment, this shell would weigh about 500 tons (455,000 kg). Magnetic shielding was discussed, but is far beyond current technology, also the biologic impact of living inside a 20 tesla field (10x a MRI scanner) are unknown.
Summary: except for the radiation problem, all technology is currently available for a manned Mars mission, or could be developed over the mission planning phase. However if spherical water shielding is used for radiation protection, this would greatly increase the payload requirement and overall costs, since you’d have to carry at least 500 inert tons to and from Mars, plus the real payload. That doesn’t make it impossible (original post said cost no object), but the required lift capacity would be very expensive.
Definitely, and it’s quite inconsistent. As early as 1961, radiation in outer space was observed to increase one person’s mass to the point where his body became so heavy, it’s like he was made of rocks. On the other hand, in another, the bone mass lost cohesion to the point where the subject’s limbs could be flexed into unusual shapes. Two other subjects were observed to show no bone-mass-related effect from the radiation.
Later attempts to reproduce the experiment have failed to show any consistent pattern.
Yes and no. The best shielding against the really heavy stuff is none at all. A single high-energy cosmic ray particle can’t do any more damage than a single lower-energy one, provided it’s above ionization energy. In fact, the high energy ones are less likely to do damage, since they’re likely to just go straight through you without any interaction. But put some shielding between yourself and that high-energy particle, and it can cascade into many lower-energy particles, each one capable of doing just as much damage as the original. So with those, you actually want as little shielding as possible, to minimize the cascades.
For solar-origin particles, remember that they travel slower than the speed of light, and there’s generally some visible indication when they’re emitted. So you could have just some tightly-cramped bunker space that the crew squeezes into when necessary, rather than shielding the entire crew compartment. You also wouldn’t need an entire shell of shielding, but just a shield in one direction, since you know which way the Sun is. And timing the mission for solar minimum might not eliminate events, but it would at least significantly decrease them (you’d probably only get one or two events over the course of the mission).
Mangetout, you would of course make the cable connecting the modules redundant, and you’d also include a safety factor in the stregth.
The thing is when I said multiply by a hundred, I was counting on the total needs, including redundancies, for the round trip, including fuel for everything that has to go both ways. Spare cables, (Is one spare enough?) spare winches. Fuel to spin and unspin, and reaction motors for the process, and a backup. Minimum fueling and efficient orbits require extremely long duration trips, and visits. That means the materiel requirements are very large, and the concept of redundancy becomes very mass intensive.
All those spare parts need tools for repairs, and EVA equipment, and atmosphere preservation equipment for multiple EVA missions. Mass, mass, mass. Every single thing you are doing takes more mass than the lunar missions, and you are doing many many things that were not necessary on the lunar missions. For all of that mass, you need original boost to orbit, support in space for assembly teams, who had to be trained on the ground to do the job. Work in space takes ten times as long, if it can be done at all, as the same work on the ground. Drop a critical part, and start over again. And almost every part is critical.
Money is equal to mass squared, times time squared. Political delay is at least as expensive as engineering delay. If you can plan a mission that would cost Two Hundred Billions Dollars, the actual mission would be much closer to a Trillion Dollars. Of course, everyone could lie about it, until the first half Trillion is already spent.
“If God had intended for man to go to Mars, He would have given us more money.” ~ an unnamed NASA official ~