Space Colonization Options (Orbiting Stations, planets/moons)
- Thread starter valkyrie013
- Start date
Question to the audience..
Let's say you build a space elevator. It extends up to geo sync orbit.
Question is, if there is a "floor/station" at the 250 mile mark. Wouldn't that station have gravity? At about 90% g?
Since it is in geo sync it isn't in freefall correct?
And at geo sync its 0.03%
Let's say you build a space elevator. It extends up to geo sync orbit.
Question is, if there is a "floor/station" at the 250 mile mark. Wouldn't that station have gravity? At about 90% g?
Since it is in geo sync it isn't in freefall correct?
And at geo sync its 0.03%
I'm thinking since it is connected to Earth it should have gravity still as there is a physical connection, or would that be wrong?
It would feel gravity but it has nothing to do with being physically linked to the Earth. The gravitational acceleration varies as inverse distance squared from the centre of the Earth's mass (GM/r^2) minus the centrifugal acceleration (v^2/r). At the geostationary orbital distance, about 42,000 km (26,000 miles) from the Earth's centre, these terms cancel out.
An orbiting body feels gravity or it wouldn't orbit but instead travel in a straight line with constant velocity. Orbiting is falling in a gravitational field with sufficient sideways velocity to miss constantly the body that is being orbited.
So how are people weightless on the ISS? Shouldn't they feel something as it's moving?
There are gravity gradient effects--some old sats have a spine with the lower end always pointing towards Earth's core though in 'free-fall'.' I think Endeavour had a radar mast with the small thruster stuck to keep the arm out "flat" but if failed..and the orbiter had to thrust to keep the mast from being pulled 'downwards' if memory serves. https://www2.jpl.nasa.gov/srtm/mast.html https://en.wikipedia.org/wiki/Shuttle_Radar_Topography_Mission
It is why the Moon is tidally locked in captured rotation...
The Moon might be a good site to try a fly-by rotorvator what with lower gravity and no atmosphere. I can see a nickle-iron slug dropped pretty much in one piece. You really need big structures to do space based radar well.
Spudis and Lavoie presented a plausible way to combine EELV and Shuttle-derived heavy lift launches resulting in a human-tended lunar outpost producing 150 tons of water per year.
file:///C:/Users/clayw10/Downloads/Affordable_Lunar_Base.pdf
https://forum.nasaspaceflight.com/index.php?topic=52892.msg2194306#msg2194306
One of the things I learned recently is that first stage boosters are given individual names.
Boris Volodya Gavrila Danila
https://forum.nasaspaceflight.com/index.php?topic=17286.msg2222588#msg2222588
R-7 is lit with a match
https://www.popularmechanics.com/sp...ctually-lights-it-rockets-with-a-giant-match/
There is a new technology in metal extraction called “electrokinetic in situ leach” mining very like key hole surgery...by Rich Crane. A seemingly unrelated hair bot using RoboWig by Josie Hughes might help with rock wool. Forust allows 3D printing of wood.
MIT’s Michael Wessely has two projects:
PhotoChromeleon and ChromoUpdate which allows a switch in surface color with a zap of light. Not only could this detail models in a flash...but maybe help with solar sails....
https://techxplore.com/news/2021-05-zap-patterns.html
Mars basecamp lander
https://www.lockheedmartin.com/en-us/products/mars-base-camp.html
https://www.lockheedmartin.com/cont...bt/Mars-Base-Camp-Update-and-New-Concepts.pdf
SLS mission book
http://www.boeing.com/resources/boe...urce/space-launch-system-flip-book-040821.pdf
It is why the Moon is tidally locked in captured rotation...
The Moon might be a good site to try a fly-by rotorvator what with lower gravity and no atmosphere. I can see a nickle-iron slug dropped pretty much in one piece. You really need big structures to do space based radar well.
Spudis and Lavoie presented a plausible way to combine EELV and Shuttle-derived heavy lift launches resulting in a human-tended lunar outpost producing 150 tons of water per year.
file:///C:/Users/clayw10/Downloads/Affordable_Lunar_Base.pdf
https://forum.nasaspaceflight.com/index.php?topic=52892.msg2194306#msg2194306
One of the things I learned recently is that first stage boosters are given individual names.
Boris Volodya Gavrila Danila
https://forum.nasaspaceflight.com/index.php?topic=17286.msg2222588#msg2222588
R-7 is lit with a match
https://www.popularmechanics.com/sp...ctually-lights-it-rockets-with-a-giant-match/
There is a new technology in metal extraction called “electrokinetic in situ leach” mining very like key hole surgery...by Rich Crane. A seemingly unrelated hair bot using RoboWig by Josie Hughes might help with rock wool. Forust allows 3D printing of wood.
MIT’s Michael Wessely has two projects:
PhotoChromeleon and ChromoUpdate which allows a switch in surface color with a zap of light. Not only could this detail models in a flash...but maybe help with solar sails....
https://techxplore.com/news/2021-05-zap-patterns.html
Mars basecamp lander
https://www.lockheedmartin.com/en-us/products/mars-base-camp.html
https://www.lockheedmartin.com/cont...bt/Mars-Base-Camp-Update-and-New-Concepts.pdf
SLS mission book
http://www.boeing.com/resources/boe...urce/space-launch-system-flip-book-040821.pdf
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I don't think you are gonna launch a full saturn V on The Moon
A tiny capsule for 3 people for months on end? There's not enough cargo space for the food that's needed, let alone the water
Oh I get it now he was taking the piss with that comment about Apollo 11
The first mission to Titan would involve an Apollo 11 design, sans systems devoted to transporting humans. The life support systems that have been removed would be replaced with additional fuel.
The Apollo 11 vehicle design would work perfectly for an unmanned mission to Titan because the design has already proven itself on the Moon.
The lander would also have additional fuel to support the unmanned mission due to life support systems for humans being removed as well.
Titan is more important than Mars because Titan does in fact have a large amount of water in its frozen surface ice and under the ice as well. Water that can be used on Mars and the Moon once it has been filtered and sanitized.
With the development of a large capacity fuel system for the Titan 1 mission, the same vehicle frame could then be used for lunar refueling. Refueling operations that would see an unmanned lunar lander, employing the guidance and control program used in Star Ship 1, docking with the refueling Titan 1 design, refuels and then returns to the lunar surface. A launch pad would not be needed which means adding Elon Musks or Jeff Bezos reusable entry rocket design to any lunar vehicle will be a success.
Titan is a waypoint oasis of the Sol system.
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Well that's a little better why didn't you say it was an unmanned ship you were thinking of?
If you want to do space trucking, you need John Canyon on board.
What about nuclear rockets?
Guess what NERVA means..
https://en.wikipedia.org/wiki/NERVA
https://en.wikipedia.org/wiki/NERVA
my bad oops
Lunar Starship is close:
https://twitter.com/infographictony/status/1392815355546849281
But I still want bigger....
Thought Experiment - NOVA Sized Payload using Shuttle Era Hardware and M1 with SpaceX retropropulsion
Upsizing the External Tank to something the size of the T10RE-1 by increasing the tank from 8.4 meters to 24.4 meter diameter and length accordingly obtains a tank propellant mass of 17,367 tonnes of propellant with 708 tonnes of inert weight. A total of 18,075 tonnes take off weight. To lift this at 1.5 gee requires 266 MegaNewtons. Each M1 produces 1,500,000 pounds force or 6.675 MN. That's M1 40 pumpsets and combustion chambers expanding on to an aerospike nozzle. Attaining its growth target o 8 MN means 33 pumpsets and combustion chambers would suffice. This is just a measure of specific impulse and mass flow rate. With a 5.5 to 1.0 oxidizer fuel ratio this is 2,672 tonnes of LH2 and 14,695 tonnes of LOX.
Three of these strapped together like a Falcon Heavy and using retropropulsion to recover the three, requires some propellant to recover the empty tank. An empty tank has a high surface area to volume, so slows to subsonic speeds as it descends. By putting the retropropulsive propellant off-center inside the later tanks at the common bulkhead between the two, a small amount of lift is obtained. Enough to stay in the lower density atmosphere at re-entry and slow speed and descent, so that without any thrust, but with a few fins, you can slow to 0.3 km/sec. So, you need enough propellant to bring 708 tonnes to 0 velocity at 0 altitude at 0.3 km/sec approach speed. At 4.59 km altitude you apply 13.9 MegaNewtons of force on the rocket to land it. At 4.2 km/sec exhaust speed you need
708*(exp(0.3/4.2)-1) = 52.421 t ~ 52.5 tonnes
of propellant. For each. So, there si 17,314.5 tonnes of propellant in each of the three boosters operated in this way.
So, we have the following equation to solve;
9.4 km/sec = 4.2 km/sec * ln((3*18075+p)/(3*18075+p-2*17314.5))+4.65*ln((18075+p)/(18075+p-17314.5))
p=1883.06 tonnes (4,151,400 pounds!!) payload.
Nearly 19x the size of Starship/Heavy payload and 29.4x a Falcon Heavy payload.
At $2 million per to$nne construction cost this is $1.416 billion per vehicle and $4.248 billion for the trio and with 5x fly away cost being the development cost this is $7.080 billion develoment cost. Supposing we can fly these 35,000 times with one chance of loss in 6.5 million (the likely goal of the Starship/Heavy system, which is admittedly challenging) the cost is $121,371 per launch. Likely half that cost for launch operations. The cost of hydrogen in quantity made from natural gas is $1000 per tonne and the cost of LOX is $400 per tonne so the cost of propellant is
3*(1000*2672+400*14695)=$25.65 million
Per launch.
Dividing this by the payload
25.65/1.88306 = $13.62/kg
With a nuclear thermal power source that uses a Westinghouse Sulphur Iodine cycle hydrogen oxygen costs can be cut to $100 per tonne when used efficiently with the fuel made from sea water instead of natural gas. That reduces the costs to
300*17367 = $5.21 million
and price per kg to $2.77!!
From:
https://www.secretprojects.co.uk/threads/spacex-falcon-heavy.12339/page-7#post-456193
