NASA Wants Astronauts on Mars by 2010 713
FeloniousPunk writes "According to
this article
in the UK Guardian, NASA intends to send a manned mission to Mars by 2010, using nuclear propulsion. President Bush may announce this project, called Project Prometheus, at the State of the Union address." Here's
good background and context;
for technical background, I recommend
Zubrin
or
Stern.
The JPL will be involved in developing the nuclear propulsion tech, intended to cut the interplanetary trip from six months to two. Apparently the theory is that this proposal won't get shot down like the last Mars proposal because the shorter mission will save money. Here's hoping public response has progressed beyond "oh no! did he say nuclear?!"
In related news,
jkcity writes:
"according to this article by the BBC, the Chinese plan to have a man in space by October 2003."
And a nod to Arthur C Clarke (Score:1, Informative)
Now we just have to keep the crazy zealots out of the exhaust pipes...
by 2010? (Score:5, Informative)
Not that i don't think we should be going there, I just don't think it will happen by then. America lost its interest in Space Travel long ago and they will have no interest in funding this. It's going to take another country doing it first to provoke America to get on the ball. Even then we'll only be doing it out of spite. Of course if this proposal is based on one of Bush's magical projected revenue formulas they won't have enough money to even buy spacesuits by then.
There is use in it (Score:4, Informative)
And lastly, "because it's there". I would entertainment in man reaching mars, it's extremely exciting don't you think? (i wonder how many extremely practical people are going to shoot me down for that)
Re:How does nuclear power help? (Score:3, Informative)
Re:How does nuclear power help? (Score:5, Informative)
Correct, and we are still talking rocket engines. Except that instead of heating and expelling propellant thanks to a chemical reaction (hydrogen + oxygen -> water), you use a nuclear reaction (pump hydrogen--or just about any gas--into a nuclear reactor, heat it like hell).
The difference is that a nuclear rocket is much more efficient: the exhaust speed is much higher. Therefore the propellant mass required for a given change in speed is exponentially lower, due to the "rocket equation":
m/m0=exp(dv/u)
where m0 is your ship's dry mass, m its total mass (including propellant), dv the change in speed you aim for, and u the exhaust speed.
Use Asymetric Capacitors instead of Nuclear Power (Score:3, Informative)
http://jnaudin.free.fr/html/lifters.htm
http://arxiv.org/pdf/physics/0211001 [PDF file attempting to explain how it works]
Re:So do I... (Score:4, Informative)
Russian astronomer Nikolai Kardashev.
Re:because (Score:5, Informative)
It's not as cut and dried as that.
I worked at the JPL last summer with the MER group (MER: the next Mars rovers). It was a great place to be and the technology they had was impressive. Still, there's only so much a teleoperated robot can do with a 20 minute time lag, slow rad hardened processors, and one (sensor-laden) arm. If I recall correctly, the off-the-cuff figure tossed around there was that a human geologist on site could accomplish in 45 seconds what an earth-based team driving a Mars rover could do in an hour.
It has always been more cost effective to send robots to Mars instead of people. Don't think, though, that you can just send one of these guys up and find out everything you want to know!
--Tom
I Have Russia's Plans (Score:2, Informative)
"I have finally found some detailed information on Soviet plans
for manned Mars exploration. "Power-Propulsion Systems for
Orbital Nuclear Transfer" by Koroteyev et al. (ACTA
ASTRONAUTICA Vol.24 pp.181,1991). The authors compare the merits
of NERVA type nuclear thermal engines, a hybrid chemical/ion
propulsion system before finally settling for pure nuclear
electric (ion) propulsion. The Russians appear to have
consistently favored this low thrust, high Isp option since the
early 1970s; this in stark contrast to NASA's plans which have
mostly been based on high-thrust chemical or nuclear thermal
propulsion. The Soviet approach to manned Mars exploration is
both interesting and strikingly different. I will first
describe the mission and then discuss the merits and drawbacks
compared with American plans such as Mars Direct.
The Soviet option used a huge nuclear reactor generating up to
50,000kW -- 450 times more power than the International
Space Station's solar panels! In addition to producing
electrical power, the reactor's thermal output can be used to
heat liquid hydrogen propellant to 2800K if the nuclear-thermal
rocket (=NERVA) option is used. A 460-day two-way mission to
Mars orbit would have to start from a high 800km Earth parking
orbit due to the radiation hazard. The total mass would be 800
metric tons, including 495t of LH2 fuel, a 150t payload, a
70t reactor/propulsion module (200kW,200kN thrust,917s Isp).
The remainder is presumably LH2 tankage.
Option#2 would feature a chemical liquid oxygen/hydrogen
rocket (1.1mN thrust,480s Isp) for quick acceleration through
the Earth's radiation belts. A 260N nuclear-ion engine would
then provide the thrust for the remainder of the journey. Total
spacecraft mass would decrease to 700t (including 310t of
LOX/LH2 propellant plus 147t of lithium fuel for the ion drive)
but the total mission duration would increase to 615 days. The
required delta-Vs from an 800km parking orbit are 3.1km/s for
the chemical rocket plus 25km/s for the low-thrust transfer to
Mars orbit & return to Earth. Both missions (option#1 & 2)
would have taken place in 2018 and permitted a 30 day stay on
Mars.
The option finally chosen was a pure nuclear-electric system
using closed Brayton-cycle gas turbines working at 1800K
temperature for heat-to-electricity conversion.
The total travel time would be reduced to 320 days. In
addition, the spacecraft would weigh less (550 metric tons,
including 300 tonnes of xenon fuel). The delta-V would increase
to 47km/s, however.
An interesting feature of the propulsion system is that the
thrust can be increased (at the expense of a decreased Isp
higher propellant consumption) for major maneuvers that have
to be carried out quickly. Most important among these is the
initial departure from parking orbit;the spacecraft "spirals
outwards" throught the van Allen belts to an ~185,000km
circular orbit in just 7.5 days. From there on, the engines
operate in a more economical high-Isp / low-thrust mode.
(Ion thrusters are very efficient because their
exhaust velocity is high, so less fuel will have to be carried
on board. The main drawback is the low thrust which means the
engines will have to be fired continuously for days or months.)
---
This "all-up" mission would begin in May 2018 and could
deliver a 4-crew to Mars orbit, where two cosmonauts would
descend to the martian surface in the MLV for 2-3 weeks of
exploration. However, it would be more economical to launch
an UNMANNED CARGO SPACECRAFT on a one-way mission in 2016,
carrying the MLV plus a "temporal research [orbital space-]
station". Payload mass in Mars orbit would be 150t, but the
total mass in LEO would decrease to 280t. This is because
the cargo spacecraft would not have to carry fuel for the
return trip and because a slower, more economical 320-day
trajectory could be used. Only one 25mW reactor would be
required so the mass of the propulsion system is reduced by
almost 50%.
The MANNED SPACECRAFT (sans MLV and carrying 53t less propellant)
would depart from Earth in May 2018."
Re:The question will not be (Score:3, Informative)
Re:All I have to say... (Score:5, Informative)
Right now, nothing even comes close to uranium/plutonium for energy density. There are really two issues: power and reaction mass. A rocket combines the two, but a nuclear propulsion system doesn't. If ice is the reaction mass, then you can "refuel" on a comet. The more energy per unit of reaction mass you can get, the less of it you need.
There are already ion engines [spacedaily.com] in existance, solar powered, but they are very low powered, incapable of moving significant mass through space at a useful speed.
Re:How did you know that!? (Score:1, Informative)
1. He wants to abolish taxes on dividends
If you knew the first thing about economics, you would know this is a good thing.
2. He wants to start a preemptive attack on a another nation
You could have fooled me. [guardian.co.uk]
3. He wants cut income taxes disproportionately in the favor of the rich
96% of federal income taxes are paid by 50% of the tax payers. It's hard to cut taxes on those who don't pay taxes. See response to point 1.
4. He wants to stop even the most mild forms of affirmative action
This is just a lie. An out and out lie. Racial quotas are illegal and unconstitutional. You do support the Constitution, right? Bush supports racial diversity, just not with programs that are illegal. Check out the program he instituted while governor of Texas.
It's no wonder the space program is in such disarray, with the amount of ignorance in those who support it. Do NASA a favor, either get educated or just keep quiet, you look foolish when you talk.
Re:How does nuclear power help? (Score:5, Informative)
Right, and it would help to use a fuel which has a low specific heat (that is, it takes little energy to heat it up) and also which doesn't take a lot of energy to go through phase changes. For each phase change a substance goes through it soaks up energy which could be better used in propulsion.
Hydrogen is better than water because hydrogen dissociates into a vapor with very little energy, where water takes a lot of energy to turn into steam. Water also will soak up a lot of energy in heating (high specific heat) up to the temperatures generated in the nuclear reaction, whereas hydrogen does not need as much energy to get up to temperature. In other words, you get more thrust out of equal masses of hydrogen and water with the same energy put into them.
However, there are other factors to consider. The main advantage of water is that it is easy to find, easy to store and pump around, can be used as a moderator for the nuclear reaction, can be used as shielding for the astronauts, the astronauts can use as their drinking supply, and they can use it to produce their oxygen supply. Hydrogen is a total mess to handle, its only real advantage is that it is a bit more energy efficient as a reaction mass. Water is generally accepted as a very good reaction mass due to these factors. The usability of water will most likely far outweigh any benefits you would get from using hydrogen.
Re:The question will not be (Score:1, Informative)
Re:Nuclear Propulsion (Score:3, Informative)
However, I think they have something in mind more along the lines of NERVA [astronautix.com], which involves pumping the reaction mass through an ordinary fission reactor. It's just like a chemical, combustion-based rocket, except the thermal energy is produced by the reactor instead of combustion, and you can get a lot more oomph.
Re:How does nuclear power help? (Score:1, Informative)
Not quite [snopes.com].
Re:So do I... (Score:2, Informative)
A slightly different classification I read went:
- Type I - Harnesses the energy of an entire planet (eg, weather control).
- Type II - Harnesses the energy of an entire solar system (eg, Dyson Sphere).
- Type III - Harnesses the energy of an entire galaxy.
A quick websearch shows this idea was from an astronomer named Kardashev.Nukes in space???!!!! *gasp* NO! (Score:2, Informative)
WHAT!!!!???? No nukes in space! It must be a joke right? Correct me if I'm wrong here, but alot of anything that matters in space is nuclear right? I mean, actually, everything you can see in the night sky is nuclear right? I mean, like all life is here, and some dark glasses, because of a rather important and bright nuclear reaction.