# Help Me Start a Martian Business

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#### piratevic

##### Guest
Hi,
How do i calculate the orbit and inclination of a sun synchronous orbit around Mars. (i need to formula please)
From what i understand, in this type of orbit the sattlelite will always be facing the sun thus allowing it to absorb solar energy 24hrs a day....am i right so far?

Pirate

Edit by MW: I renamed the thread so could consolidate them...

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#### MeteorWayne

##### Guest
Re: Sun synchronous Orbit

That is not what a sun sychronous orbit it. That is an orbit that passes over the same points on the planet at the same time each day on earth, or Sol on Mars.

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#### piratevic

##### Guest
Re: Sun synchronous Orbit

oh ..damm
so what is an orbit that receives the rays of the sun 24hrs called?

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#### piratevic

##### Guest
Artificial Gravity in a Torus

How do i calculate the rpm a torus should rotate to produce a gravity?
i think it depends on radius of the torus..i just need the formula please

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#### piratevic

##### Guest
Mars liftoff problem

Hi,
what kindoff engine could i use to launch a ship from the surface of mars to its orbit.
I think the escape velocity of mars is 5km/s
This is around the year 2040.
We were thinking ion engines, massdrivers, electrostatic engines.
Anything better?

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#### origin

##### Guest
Re: Artificial Gravity in a Torus

piratevic":2cctyqmh said:
How do i calculate the rpm a torus should rotate to produce a gravity?
i think it depends on radius of the torus..i just need the formula please
A rotating torus cannot produce gravity.

I guess you are asking what is the radius and speed of a rotating body that will produce a centripetal froce equal to earths gravity.

So you need the acceleration to equal 9.8 m/s^2

Acceleration = r X W^2

where W is the angular speed:

W = 2 X pi X f

Where f is the frequency of the rotation.

This is for a constant speed, which is what you would want in this situation, I assume.

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#### piratevic

##### Guest
Re: Artificial Gravity in a Torus

yea thats exactly the formula i want! thank you very much

are you sure that a rotating torus cannot produce psedo gravity? i've seen a lot of examples of space settlements and they all work on rotating torii. by rotating i mean spinning.

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#### MeteorWayne

##### Guest
Re: Sun synchronous Orbit

Good question! I'm not sure I know the answer

I see what you are getting at. It would have to be a polar, or near polar orbit. (Since around any planet but Uranus, an equatorial orbit is in eclipse at times.

If it was a true polar orbit, it would have to be high enough that eclipse was avoided...currently Mars' obliquity (axial tilt) is about the same as earth.s Time to do some trigonometry!!

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#### MeteorWayne

##### Guest
Re: Artificial Gravity in a Torus

But that's not really gravity. It's acceleration equal to the earth's gravity

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#### MeteorWayne

##### Guest
Re: Sun synchronous Orbit

Yes, I know there is a sun sychronous orbit, but that is not specifically what he was describing.

It is a subset of the sun synchronous orbit...I think this is it:

The dawn/dusk orbit, where the local mean solar time of passage for equatorial longitudes is around sunrise or sunset, so that the satellite rides the terminator between day and night. Riding the terminator is useful for active radar satellites as the satellites' solar panels can always see the Sun, without being shadowed by the Earth. It is also useful for some satellites with passive instruments which need to limit the Sun's influence on the measurements, as it is possible to always point the instruments towards the night side of the Earth. The dawn/dusk orbit has been used for solar observing scientific satellites such as Yohkoh, TRACE and Hinode, affording them a nearly continuous view of the Sun.

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#### piratevic

##### Guest
Re: Sun synchronous Orbit

yes, thats exactly what im talking about!

well the basic idea is, me and my team are desiginig a space settlement in the orbit of mars, so to get the maximun amount of solar power there is an orbit which faces the sun 24hrs.

how do i find the altitude and inclination? from what i understood so far is that as alitude increases inclination decreases.

is there some relation between them i could use?

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#### piratevic

##### Guest
Re: Artificial Gravity in a Torus

uh..it makes the people stick to the edges of the torus right? ...thats all i really want lol
i think its called psedo gravity?

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#### MeteorWayne

##### Guest
Re: Sun synchronous Orbit

Actually, the sun synchonous orbit page linked above is a good starting point. It must be sun synchronous to start with, as you can see from that page there are a lot of different configurations.

Then you need to ensure that it is a dawn/ dusk obit, which I think to work well for your purposes, must be near circular. And you need to be high enough to be out of the atmosphere.

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#### piratevic

##### Guest
Solar Panel Collection

How do i calculate the amount of light that a solar panel absorbs in the orbit of mars?
i think the highest solar panel efficiency till now is 40%

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#### MeteorWayne

##### Guest
Re: Solar Panel Collection

I assume you're going to pay us for doing your work for you?

I am going to merge this into the other thread and give it an appropriate name.

Have you never heard of Google???

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#### drwayne

##### Guest
ROM Estimate would be about 40% of Earth

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#### mrmorris

##### Guest
Re: Mars liftoff problem

piratevic":2nb9p4vp said:
what kindoff engine could i use to launch a ship from the surface of mars to its orbit.
...
We were thinking ion engines, massdrivers, electrostatic engines.
Ion engines, electrostatic, VASIMIR and other such high-impulse engines do not produce thrust in excess of the mass of the engine itself (even in 1/3 gravity). They cannot be used to lift from a planetary surface.

A mass driver if considered to be a land-based railgun launching the ship would be more feasible on Mars than Earth given the lower gravity and thinner atmosphere. However, it would require umpteen kilometres of rail be constructed on the surface which seems unlikely. If the 'mass driver' is internal to the spacecraft (i.e. magnetically accelerating reaction mass), then the same problem exists as per ion engines with thrust-to-mass ratio.

Chemical, nuclear-thermal, bomb-pumped, or laser-launched craft are the only four options off the top of my head. Nuclear thermal has many advantages, actually, but good luck on getting approval to build one (and double that on bomb-pumped). The tech on laser-launched craft isn't there yet. Chemical is pretty much the only option you have.

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#### EarthlingX

##### Guest
Re: Artificial Gravity in a Torus

piratevic":1aiqwr4y said:
How do i calculate the rpm a torus should rotate to produce a gravity?
i think it depends on radius of the torus..i just need the formula please
Here is a calculator to play with :
SpinCalc an artificial-gravity calculator
from this thread:
Relativity Calculator
where you will also find links to many more calculators and information that might relate to your project.
Artificial gravity on Wikipedia:
http://en.wikipedia.org/wiki/Artificial_gravity

Here is a link to help a bit with the orbit calculations:
http://en.wikipedia.org/wiki/Orbit
and most of what you need to know about Mars here :
http://en.wikipedia.org/wiki/Mars

Here is a bit about spacecraft propulsion that might come handy:
http://en.wikipedia.org/wiki/Spacecraft_propulsion

and about traveling through the space:
http://en.wikipedia.org/wiki/Hohman_transfer
http://en.wikipedia.org/wiki/Interplanetary_network

and getting there:
http://en.wikipedia.org/wiki/Space_launch

and about Solar radiation:
http://en.wikipedia.org/wiki/Solar_radiation
where you can get formula for different orbital elements and a table with numbers for different planets.

Google Earth has option to select Mars as a planet, and is very neat.

If you aim for space station in Mars orbit, why not use Phobos ? It will help you at least with radiation shielding, though artificial gravitation might be a bit trickier.
http://en.wikipedia.org/wiki/Phobos_%28moon%29
Mars also has Lagrangian points, and Mars-Sun L1 is always in the sunlight, if i'm correct.
http://en.wikipedia.org/wiki/Lagrangian_point

If you could make fuel out of things found on Phobos, your business could refuel ships traveling from Mars to other destinations. It would be cheaper than lifting it from Mars surface.

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#### piratevic

##### Guest
thanks EarthlingX, we used almost all the links you provided us.

Regarding construction at Langrage points and phobos, we have rules that do not permit us to do so im afraid.

but we did design a mining base at phobos to construction materials specially carbon.

a doubt : when using an SPS, which is about half way the distance between mars and earth, do we have to use a really big receiver for the microwave beam?

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#### EarthlingX

##### Guest
piratevic":1asl4oug said:
thanks EarthlingX, we used almost all the links you provided us.
No problem, glad i could help
piratevic":1asl4oug said:
Regarding construction at Langrage points and phobos, we have rules that do not permit us to do so im afraid.
Did i miss explanation of those rules ?
piratevic":1asl4oug said:
but we did design a mining base at phobos to construction materials specially carbon.

a doubt : when using an SPS, which is about half way the distance between mars and earth, do we have to use a really big receiver for the microwave beam?
If by SPS you mean Solar Power Satellite
http://en.wikipedia.org/wiki/Solar_power_satellite
and if you are talking about wireless power transmission
http://en.wikipedia.org/wiki/Wireless_p ... ansmission
using microwave power transmission
http://en.wikipedia.org/wiki/Microwave_ ... ansmission
then this paper:
(Wireless Power Transmission for Solar Power Satellite (SPS) )
http://www.sspi.gatech.edu/wptshinohara.pdf
might provide some answers and, at least for me, some math refresher about cones like this:
http://en.wikipedia.org/wiki/Cone_%28geometry%29
could also help.

You will show us your results, right ?

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#### piratevic

##### Guest
thanks, most of our SPS problem is solved

sure i will, our deadline is dec 10th, you will have a copy of our report in our mail box well before that

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#### piratevic

##### Guest
can i use a carbon dioxide rocket propulsion system to get a plane from the mars surface to orbit?
i guess it will need to go faster than 5.1km/s to attain escape velocity.

im thinking of this cause the martian atmosphere has got 95% co2

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#### EarthlingX

##### Guest
piratevic":3jbt2dwt said:
can i use a carbon dioxide rocket propulsion system to get a plane from the mars surface to orbit?
i guess it will need to go faster than 5.1km/s to attain escape velocity.

im thinking of this cause the martian atmosphere has got 95% co2
Sure, but you will need some other elements too:
(METAL-CO2 PROPULSION FOR MARS MISSIONS: CURRENT STATUS AND OPPORTUNITIES.)
http://www.lpi.usra.edu/meetings/roundt ... rovich.pdf

If you check rocket fuels available
http://en.wikipedia.org/wiki/Rocket_fuel
or here
http://www.astronautix.com/props/index.htm
or at least commonly used fuels:
(ROCKET PROPELLANTS)
http://www.braeunig.us/space/propel.htm
you might notice, that most commonly used element is hydrogen, combined with others, to different effect.
Here is a starting point to finding out what and how with co2:
http://en.wikipedia.org/wiki/Carbon_capture_and_storage
and a promising chemical reaction:
http://en.wikipedia.org/wiki/Green_Methanol_Synthesis

XCOR might have some news about this:
(Methane Rocket Engine Successfully Tested)
http://www.space.com/businesstechnology ... ocket.html
which, i think, is related.

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#### MeteorWayne

##### Guest
I hope you get a good grade, EarthlingX

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