Re: Improved lunar landing architecture

On 14 Aug 2005 10:10:41 -0700, "Alex Terrell" <alexterrell@xxxxxxxxx>
wrote:

>Cardman wrote:
>> I doubt that you could pick a better location for a base, when they
>> would just need to dig a well and to haul up ice.
>
>That's what I meant. Relatively clean ice, rather than a 3-10% water
>conent that needs hauling and heating. I agree that that is a benefit
>that Mars probably has.

I don't think that you quite understand how wet Mars actually is. As
your common soil alone is estimated to be 30% to 50% full of water by
volume. Water ice is all over the place in other words, where it
should only be a short distance down.

And then there is plenty of water ice at the poles, where it is stable
on the surface in these regions. There is so much water ice here that
it will come half way up to your knee, if it all melted and covered
the whole planet to an equal depth.

So there is no water problem on Mars. This one mention area is just
interesting because there should be a sea size volume of frozen water
right near the equator.

In their base they could make themselves a swimming pool. I wonder if
they would suffer an algae problem?

>Sorry, I meant 4,000 km out, or up, for launching to Earth. Phobos is
>actually a mean of 9270 km from the centre. So 5,900km downwards, would
>enable escape from Mars with a delta V of only 400m/s.

Pending some effort to get hold of the end.

>> Oh and that reminds me. Let me go make an eBay advert requesting a
>> 8000 km long tether delivered to Phobos orbit.
>>
>It wouldn't weigh much and could be made of Spectra 2000. Just like
>some fishing rods.

Still sounds like a serious project to me.

>And Mars doesn't have a large space debris problem.

Not yet. <grin>

Just wait until us humans get there in other words.

>I haven't run the mass equations, but I'm pretty sure this is well
>within the capability of spectra. Nano tubes are not required.

Then it seems reasonable.

>> >That would allow Mars surface to transfer orbit with almost no fuel
>> >required
>>
>> You underestimate Phobos's orbital height, and that 2.138 km/s has to
>> be handled somehow.
>
>lowering and raising cargos might cause some swinging of the tether,
>but the 2.138km/s comes from Phobos. The bottom of the tether travels
>at about 400m/s faster than the surface.

Ah, so it does. Damned angles.

So they have to go 3370 km up and catch this tether going at 400 m/s
roughly. Sounds interesting.

>> Massive engines and a medium weight power source is my plan. Getting
>> that initial kick is the hard part, where it may need a little booster
>> help, but after that it is cruise mode for a few months.
>
>Massive engines need a massive power supply. Assume about 1km2 solar
>array, or 1,000 tons for 100 MW. Nuclear would be heavier, as would
>solar at Mars orbit.

Seems like you have not been looking into NASA's Prometheus project,
when their hardware comes desktop sized. Although I would have to
seriously look into the power output of one of these.

It can power their desktop sized large ion engine at least.

>> However, here is your prefect massive ion engine power source. The
>> only following issue is keeping this radioactive overheating monster
>> away from everything else. That problem can be solved.
>
>I still think it'll never beat chemical or nuclear thermal for short
>trips of 1 month.

Yes, but Mars is noted down as 7 months. And well going beyond Mars
would benefit even more. To do that quicker using the chemical method
needs ever increasing fuel storage.

>Electric propulsion is great if you have lots of
>energey. But that takes lots of time.

Well we will see how well this project works out. Ever since JIMO was
killed for being too advance and impractical, then Prometheus has been
put on the long slow development track.

>If you want something really big, go for Plasma engines. But you're
>always power limited.

Yes, power is always the limiting factor. So engines and efficiency
all depends on good nuclear power generation, while trying to minimise
the mass.

I would one day love to see figures on just what sort of craft our
best nuclear power generation and best interplanetary engines could
come up with. Something to cruise around the solar system at least.

And you are correct that external beamed power could help to lower the
mass, but that seems all voodoo to me.

In any case large xenon ion engines seem the way to go, when I have
yet to see any plans for an oxygen plasma engine. The power needed to
make that plasma should be quite demanding.

Cardman.
.

Relevant Pages

  • Re: Improved lunar landing architecture
    ... that Mars probably has. ... fire the engines at perigee. ... and out to high orbit. ... > Massive engines and a medium weight power source is my plan. ...
    (sci.space.policy)
  • Re: Is it this easy to live on Earth?
    ... nitrogen and water 5,000x from Mar's atmosphere - to provide water, ... oxygen and nitrogen - needed to sustain life on Mars. ... needs about 10 watts per day for this purpose - out of a budget of 165 ... an average power usage rate of 10 watts. ...
    (sci.space.policy)
  • Re: On Hydrogen Fuel
    ... Consider a voyage to Mars for instance. ... Solar arrays could continually electrolyse water to provide not only O2 ... For instance, for orbit insertion at Mars, you'd need ... requires power to spin it. ...
    (sci.space.shuttle)
  • Re: Is it this easy to live on Earth?
    ... nitrogen and water 5,000x from Mar's atmosphere - to provide water, ... oxygen and nitrogen - needed to sustain life on Mars. ... needs about 10 watts per day for this purpose - out of a budget of 165 ... an average power usage rate of 10 watts. ...
    (sci.space.policy)
  • Re: Improved lunar landing architecture
    ... >The main beneift of high launch sites is optimum engine performance. ... Moon before Mars I am sure. ... fire the engines at perigee. ... Massive engines and a medium weight power source is my plan. ...
    (sci.space.policy)
Loading