OK - so 2001 style, we find out that we need to get our asses to Mars ASAP.
This becomes a major national priority - and it’s essential that the US beat the EU or the Japanese or the Chinese or whoever there, for whatever reason. Gotta get to that obelisk!
The mission is to be handled in a military fashion, and is of sufficient importance that other spending cuts are made if necessary: withdrawal from Iraq, Germany, South Korea, Japan, even mothballing a carrier group. As part of the military ethos, some level of risk is considered acceptable.
So basically, a Manhattan Project for getting to Mars. How fast could it be done?
What about Jupiter?
For Mars we need to get there, land a crew and bring it home. For Jupiter - get into orbit and get home. In a pinch, a volunteer one-way suicide mission might be considered.
Starting today, how long? One year, 3 years, 10 years?
With extant chemical rockets (allowing just beyond Earth escape velocity) and a minimum energy Hohmann transfer to and from Mars, the travel time (each way) will be 8-9 months with an ~459 day layover to get in position for the return flight, for a total trip time of around 31-32 months. (I’m using round figures because the actual numbers will depend on how much extra thrust beyond merely escaping Earth orbit you can develop.) This would represent an extraordinary effort, i.e requiring the integration of multiple components in orbit, and the mission duration would be roughly twice as long the current longest mission length in an Earth orbit station, not to mention that you’d be beyond Earth’s protective magnetosphere. This is beyond the state of current technology to do, though not unforseeably beyond. However, I think using chemical propulsion would be marginal, risky, and frankly foolhardy, like trying to cross the Atlantic Ocean in a sea kayak. You could do it, but there are safer and more effective ways to travel.
Using existing (but not man-rated) high I[sub]sp[/sub] propulsion systems like some kind of ion drive you could knock this down by a factor of two or more, plus this would give you somewhat more flexibility in terms of your mission planning and interval time. However, such systems have not been developed for the size of vessel we’d talk about; they’re used mostly for stationkeeping or maneuvering, not primary thrust. Deep Space 1 used NASA’s NSTAR electric ion thruster on a continuous thrust basis , but the levels of thrust produced are around a tenth of a newton. The Hall effect thrusters used by many Soviet craft are even less effective, so I don’t think you can count this as propulsion systems you can use ASAP.
Jupiter is more complicated; some of our missions to Jupiter have involved swing-by trajectories around Venus to both pick up more velocity (more to get into the correct position to intercept the planet rather than pure speed) and extend the mission parameters to accomplish more science goals while maximizing payload. However, while this is feasible with a robotic probe that can be hardened against radiation, doing so with a human crew would subject them to greater hazard of solar flare radiation. You’d prefer to send them away from the Sun as fast and as far as possible, keeping the transit portion inward of Mars orbit as short as feasible. You wouldn’t want a trajectory like that of Cassini-Huygens.
I don’t think you could make Jupiter in a manned interplanetary craft using extant chemical propulsion. The efficienies are too low (requiring significantly more propellent/fuel, most of which is used to haul around other fuel) and the lifesystem requirements become prohibitive with increased mission duration. For any reasonable mission duration–less than a decade–you’re going to need I[sub]sp[/sub] in the low- to mid-1000 second range wth a credible amount and duration of thrust to achieve significant delta-V, which is substantially beyond the capability of even speculate chemical rockets.
Using nuclear pulse propulsion like that of Project Orion would put you comfortably into that range and requires only a (relatively) modest extension on existing technology (for fission or boosted fission propellent bomblets). The real problem with Orion is actually scaling it down to a size that’s still big enough to moderate the impulses but small enough to be conceivably lifted to orbit, even in pieces. (I’m assuming that you’re not going to get the buy-in to launch a nuclear pulse rocket directly from the surface, even though it seems feasible and even advantageous to do so with only a manageable level of environmental contamination.) Anyway, without working through the actual trajectories, I’d expect you to be able to make this transit on the close order of a couple of years and similar on return, with considerable flexibility regarding your stay-over.
Another advantage of going to Jupiter, besides getting away from the Sun’s punishing radiations, is that you have a massive and graduated atmosphere to perform aerobraking maneuvers, and a large system of moons about which you can perform navigational swing-bys for low-cost in-system manuevering (although to stop and actually land on a Moon is going to take a lot of energy).
So, in short, not really feasible with anything off the shelf, or even in current development. It’s not inconcievably far from possibility, but even with a crash development effort (far greater than the Manhattan Project, the Minuteman ICBM program, or even Mercury/Gemini/Apollo) it would be more than a decade (I would estimate 20 years) before such a trip would be feasible as anything more than a suicide mission, if possible at all.
That’s an interesting question with several components to the answer, not all of the data to which is in the public domain, I’m sure. The Project Orion crew at General Atomics crew under the famous Freeman Dyson did significant conceptual design and proof of concept work (short of actually developing or detonating nuclear devices) including an operational scale model of an Orion using conventional plastique explosives as the propellent, and a bomblet feed system therefore. There are huge chunks of testing, development, and detail design that would remain to be done, but the essential concept was fleshed out.
A larger problem would be the bomblets; from a military and political standpoint there’s really no difference between these bomblets and a so-called tactical nuclear weapon, so the circumspection and security around them would be very high. And actually producing them would be a problem; due to lack of popular demand for the fabrication of shiny new nukes, the US has let our ability to produce weapons–excuse me, fuel-bomblet–grade material lapse. This would require a substantial investment in new facilities to produce and process appropriate material. However, given the age and technical obsolescence of existing processing facilities this might not be a bad thing. But, even in full-on crisis mode, you’re going to have a NIMBY problem; nobody wants a view overlooking a plutonium production plant.
Orion was and is, essentially a political problem. The technical hurdles are not insignificant, but they’re not showstoppers, either. I think you could have one flying inside of a decade or less if you had the political will to do so.
I think we could go for nuclear engines instead of chemical. Not the explosive type, but just to heat the propellant much more then chemical.
One of the plans for mars I heard it to launch everything before we send people. That means housing, power, water, food, air facilities, return rocket. Once that’s all there then we can go. I’d say that in a pinch Mars is doable.
Jupiter OTHO is not yet in our reach. I would think that we would need to find a way to medically induce hibernation or something along those lines. Even still I can’t see it being more then a one way trip.
We were able to go from basic rocketry to the Moon in 8 years. Of course, this would have been quicker had the Soviets (with the LEM) and the US (with the rocket) worked together. You’re post says that the US is working alone so assume an upper limit of 8 years. It is true that we know how to get there with current technology but how do you take 3 years of supplies (food, water, oxygen) per person? A new technology would have to be invented to either increase the efficency of current rockets (like turning an incandecent bulb into a florescent bulb) or a new propulsion system. Let’s say this takes a roughly the same time to develop the Saturn V (5 years). We already know how to survive for extended times in space and can test out new theories on space stations (a luxury not available to Mercury/Gemini/Apollo) and how to do insertions/rendezvous manuvers (as long as NASA knows the difference between English and metric).
Long story short: Approximately 4 years 332 days 8 hours 9 minutes 48.701 seconds
Hmm … suppose some immensely powerful alien superweapon is discovered by a robotic probe. Not only is it set to fire on earth and could do so at any time, but will offer total world domination to whoever gets their hands on it.
People are needed because it’s not clear exactly what needs to be done to deactivate it or bring it back to earth.
Obviously the aim is to get there and steal it, but if it’s found to be immovable or whatever, then just a suicide mission to get there and point it into deep space or blow it up will do.
Cymro
Hmm, how about a mayday from an alien ship thats coming into the solar system and only makes it as far as mars, and they only have so much life support left.
An alien intelligence test ? Aliens tell us that unless we reach the goal within, say, fifteen years we will be judged too stupid to live and annihilated. Or a practical joke by aliens who tell us we’ll be blown up if we fail, and leave an insulting letter at the target. . .
I highly doubt it. It’s not bilaterally symmetrical, so imparting thrust to it in such a way that it didn’t tumble out of control would be nearly impossible. It also would probably fall apart under the strain - it wasn’t built to be a ship, but a station.
Minor question sparked by “Stranger on a Train”'s excellent post above.
Re the atmospheric braking manuver at Jupiter. Does Jupiter present a radiation hazard itself? I think I remember from somewhere something about dangerous radiation belts around Jupiter.