Project Space Ark

[Dman1410]

i have a suggestion its a bit far fetched but seeing as the rear section stays in orbit why not make it double up as a observatory station to monitor the planets state, weather etc.
or allow to have something like in the new star trek movie to hold it in orbit a type of orbital anchor

 

[vonneuman]

Ok, just thinking, the fact that the ozone layer is collapsing and it can't be stopped means that humans can not terraform. Because if they could they would have fixed earth. Right?
So that means that the ship will be ether A) A space colony, or B) An interstellar transport going to a already inhabitable planet.
Also you will need two rotating sections on the ship. That way they cancel each other out.

 

[The Shadow]

zeldafan: I'll pass on rebuilding the Deathstar since it wouldn't be able to actually land on the planet, and making a DeathStar type craft is not what I want to do.

dman1410: It wouldn't be too crazy to put a weather radar on board, I can make the mesh, but for coding it, might be too much hassle.

I do not think an "anchor" would be useful here since it would want to fall towards the planet rather than pull away.

vonneuman: OK. So the scenario isn't possible, but it was just to get the scope of what I'm trying to build. You can interject a better scenario for a Mars terraforming trip if you wish. Say an huge astroid was detected and will hit Earth in 20 years and it is the size of Venus. Whatever we do there really are not many plausible ways to destroy Earth and us humans survive.

 

[Hielor]

dman1410: It wouldn't be too crazy to put a weather radar on board, I can make the mesh, but for coding it, might be too much hassle.

What would you have to code? Orbiter doesn't have any weather for you to track anyway...

 

[T.Neo]

That way they cancel each other out.

You don't need to do this- there are many concepts that have no counterrotating centrifuges.

Also, I'm skeptical about a lifting body that large. Perhaps a fleet of smaller landing craft would be better.

 

[jedidia]

The front is designed to be a huge lifting body/flying wing design that should be able to fly into the atmosphere, once velocity is reduced it can do a nose down approach until it is close to landing, then it would pitch up hard and hit the hover thrusters to stop the forward momentum and make a hover landing.

That would be a hell of a ride for such a beheamoth, with all the people on board... of course Mars gravity is lower, and the atmosphere a lot less dense, but I still doubt that something that massive could make a save reentry without eliminating most of the orbital speed before hitting atmosphere.

On second thought, a very shallow reentry that takes several orbits to get deeper in the atmosphere might work rather nice. It will be difficult hitting a specific place, but I think it should be possible to bleed of the speed slowly during the course of a few days (bringin other problems along like how you're going to care for the passengers for that period of time, but let's focus on the technical aspects).

How to savely touch down anything that big might still be a problem, though. Maybe it would be a good time to start making up some dimensions and estimated weights, we can't really say anything until there's some more tangible data on the table.

Mesh looks nice so far :thumbup:

Also you will need two rotating sections on the ship. That way they cancel each other out.

Allthough a ship with only one centrifuge is a bit counterintuitive to manouver (you turn right, the ship pitches down... whuzz?), there is really no reason why you HAVE to have a counter one. A computer could easily translate the command signals and distribte them to the right rcs thrusters, so that you'll actually be moving the way you steer. No big deal.

 

[T.Neo]

Allthough a ship with only one centrifuge is a bit counterintuitive to manouver (you turn right, the ship pitches down... whuzz?), there is really no reason why you HAVE to have a counter one. A computer could easily translate the command signals and distribte them to the right rcs thrusters, so that you'll actually be moving the way you steer. No big deal.

Yeah. A spacecraft is not a fighter aircraft, figuring out methods of manuvering should be easy enough.

 

[vonneuman]

It is like a helicopter. The reason for the tail rotter is to make the helicopter spin in the direction opposite of the direction that the main rotter is causing it to spin. Because as the main rotter spins one way it causes the body of the chopper to spin the other way. For every action there is an equal and opposite reaction.
Because a tail rotter doesn't work in space you need something more like a chunuk:

The blades rotate in opposite directions, canceling each other out.

 

[jedidia]

Because a tail rotter doesn't work in space you need something more like a chunuk:

you forgott a slight detail, which is that the main rotor also won't work in space. You'd bring it up to speed, and if you constructed it well, it will stay at that speed without you aplying any more force.

ACCELERATION of the centrifuge will induce momentum into the ship (if you use a ship-bound motor to speed it up, that is. If you use thrusters located on the centrifuge itself, it won't even then). turning it at a steady speed will not. It will merely alter the direction of the momentum aplied to the ship... if the centrifuge is frictionless, anyway.

in reality, there probably would be a small amount of momentum induced because of the centrifuge gradually decellerating due to friction... but that could be countered just as easily by speeding it up again with a motor. So, bring the centrifuge up to speed with thrusters, and keep it there using a ship-bound motor, and you won't have any momentum changes in the ship.

For every action there is an equal and opposite reaction.

exactly. So, once the centrifuge rotates, there is no action anymore, because you don't need to apply force to keep it spinning. hence there is no reaction. if you have to use a force to keep it spinning at a constant speed, that means that it is deccelerating on its own, hense you're actiolly giving the reaction to the action. Anyway you look at it, the forces cancel each other out without changing the momentum of the ship.

 

[vonneuman]

What do you think is decelerating the ship? The friction. Because the rotter is on a non spinning part of the ship it will decelerate. Also the motor you use to spin the wheel will impart an equal but opposite force on the motor, and the ship its attached to, causing it to spin in the opposite direction.
If you use thrusters to spin the wheel you still need a motor to prevent it from spinning the rest of the ship. Now you have the same problem as before. When you have a large spinning mass like that the friction caused by it touching the non-spinning ship will impart a force on the ship.
If you spin the wheel with a motor a clockwise 3rpm, then you are causing the ship to spin counterclockwise at 3rpm.

 

[The Shadow]

I have no clue about what a real physics scientist might think, but I have come up with a simple solution:

Place little rocket engines on the outside of the gravity wheel, this way you can get the gravity wheel up to speed without actually affecting the rotation of the rest of the ship. Once at full speed there will be some friction from whatever is used to maintain the airtight seal and hold the gravity wheel in place, and this friction will impart some rotational energy to the central part of the ship, so use an electric motor to keep the gravity wheel moving at optimal speed relative to the ship and use the ships RCS to cancel the rotation. Since things in space keep spinning indefinately then the ship will be "rotating" clockwise continually relative to the gravity wheel. At this point only a small amount of RCS would be needed every now and then in order to reduce the rotation caused by the motors.

Or just skip the motors entirely and just use tiny rockets to keep the gravity wheel moving; using RCS to keep the main part of the ship in null rotation.



about the lander having a hard time entering the atmosphere; I saw the problem with that. I agree with jedida; a very shallow entry, stay way up in the atmosphere until it is going real slow, as it gets slower just reduce the altitude a bit at a time, once the speed is low and it's lower in the atmosphere, go nose down to keep airspeed up until it is time to land.

I've added two linear aerospikes though, just in case it needs a little push to keep from going too deep into the atmosphere too soon, or in case it needs a little more cross range in order to make it to the right landing spot.

vonneuman:

like a chunuk

Just to let you know; it is called a Chinook

Hielor: I recognize that there is no weather in Orbiter, that is why it would be such a pain, not only would I need to make weather tracking but the weather too! :uhh:

But if I did that then at least one good thing would come out of it... the weather man would always be right for a change! :lol:

 

[Chub777]

Well when the engines drop-off you could turn the tanks into wet-workshops. There would be say two or three landers docked to the workshops and the scientists send the landers to get rocks and samples. The lander flies up into space, Apollo LM style, and dock with the workshop. The thing is, when all of the landers have been used up and there's a fire onboard, the scientists can evacuate, but can't land on the surface. The landers would need powerful engines to get into Mars orbit using one stage (SSTO).

 

[jedidia]

What do you think is decelerating the ship? The friction. Because the rotter is on a non spinning part of the ship it will decelerate. Also the motor you use to spin the wheel will impart an equal but opposite force on the motor, and the ship its attached to, causing it to spin in the opposite direction.

that is exactly the point. let's take it slowly: If you accelerate the centrifuge clockwise with a motor, the ship will get a counter-clockwise momentum. If you deccelerate the Centrifuge again (accelerating counter-clockwise) the ship will get a clockwise momentum.

So once you have the centrifuge up to speed, the slight friction will decelerate it, giving the ship a clockwise momentum. If you use a motor to accelerate it again, the ship will gain a counter-clockwise momentum. Hence, if the centrifuge is constantly decelerated by friction and at the same time accelerated by a motor (I.E. kept at constant speed) the clockwise momentum induced by the deceleration and the counter-clockwise momentum induced by the acceleration cancel each other out. There is no change in the ships momentum.

You will have to correct a bit with rcs while bringing the centrifuge up to speed, yes, but once it's there the problem is gone.

Or just skip the motors entirely and just use tiny rockets to keep the gravity wheel moving; using RCS to keep the main part of the ship in null rotation.

That would be a terribly inefficient method. Electricity is easy to come by, fuel isn't.

 

[The Shadow]

That would be a terribly inefficient method. Electricity is easy to come by, fuel isn't.

I agree, but it is still an option, and in brainstorming the idea is to just throw out every idea that comes no matter how crazy or inefficient it may seem.

I'm still working on the mesh, I've restructured the gravity wheel. Such a massive object needs a bit more finesse than just slapping a steel rod on it to keep it up, so I've done a bit of structural engineering. The new design is thicker from front to back and curved to support the bit of flex that will occur, the curve also has the benefit of assisting with getting on and off of the gravity wheel while it is spinning, but it would be a bit difficult to explain my reasoning, but in general it would feel like walking downhill when going from the middle to the outside, except for the gradually increasing feeling of gravity.

 

[jedidia]

but in general it would feel like walking downhill when going from the middle to the outside

Must be quite some curve in the transfer tunnel then (I would expect it to meet the centrifuge almost tangentially), but I think it's a cool Idea and a nice detail.

 

[The Shadow]

It is a pretty steep curve, you could almost use it as a slide. You are right; it comes out of the cental shaft tangentially, does a 180 bend and ends with the people walking on a platform that lies parallel to the main section of the gravity wheel, then they would walk down some stairs with the full effect of the gravity wheel(maybe an elevator would be better than stairs after hours of walking in low gravity?).

The only problem I see is that it will take them a day to walk back while contantly fighting inertia.


Another idea I had was to have the gravity wheel gradually slow down to Mars gravity and get the people acclimated to the lower gravity.


From a psychological standpoint; which would you enjoy more? Sitting in a large spaceship or a smaller base on Mars? Because terraforming would take so long staying in space could be an option, but what would it do to the emotional health of the population?


ALSO


I think I have enough in the way of planning how to get the ship to Mars, now for actual math and logistics. What would we need to transport:

350,000 species of plants
animals:
6433 amphibians
10,000 birds
31,500 fish
5,400 mammals
8,225 reptiles
Millions of species Archeae(microscopic non-bacteria life)
and even more species of bacteria!

add it up: 414,358 non-microscopic life. Many need a male and female, so double that, now to preserve genetic diversity you need to multiply that by somewhere around a hundred(or have 4 geneticaly altered versions that have ALL of the chromosomes of the entire species!). What are we up to now?

82,871,600 specimens. Almost 83 MILLION life forms!!!!!

NOW add the microscopic life. :blink:


Considering that we can now produce living creatures from DNA and "blank" embryos, it is possible to stuff a Blue whale into a test tube and ship it in a block of ice.

If the DNA of every species could be preserved this way in space, what would it take? Estimating 100 million vials of DNA with each at about 1"x5" per tube that means that the vials alone would take up 500 million square inches(Stupid American! Everyone uses metric! :rofl. We now have 1.27 billion square cm or 1,270,000 square km! (check my math, I'm not used to metric) Australia is 983,482 square km!

This is just for the DNA; add the equipment for cold storage, the whole automated lab that grows all of these. Then you need food, water, and shelter for all of them while they are growing.

We may need to drag a planet along with us...


When I said big, I meant it.

 

[jedidia]

um, I'd throw in the third dimension. After all, you can store that stuff in cubicles.

We now have 1.27 billion square cm or 1,270,000 square km!

edit: sorry, made a mistake. your whole conversion is screwed up, and I made the same mistake when converting from square inches to square centimeters. give me a minute...

Another idea I had was to have the gravity wheel gradually slow down to Mars gravity and get the people acclimated to the lower gravity.

getting accustomed to lower gravity isn't quite such a problem. I'd spin the wheel for martian gravity right from the beginning. It's increasing the gravity that takes a bit more care.

 

[Sky Captain]

I think with advanced technology it should be possible to scan and store the DNA information on some electronic data storage device so you could have only some HDD`s instead of millions of vials lying in refrigerators.

 

[jedidia]

Ok, here goes the conversion. yours is off, a loooong way, thankfully in the right direction. We won't have to carry australia along after all...

first, when converting from square inches to square centimeters, you have to multiply with the SQUARE of the factor 2.54, that's 6.4516.

so 500 million inches^2 are 3.2258e9 cm^2. Now don't get worried, because that numbers going to get a LOT smaller when we convert it up.

one square meter is 100x100 centimeters, that's 10,000 square centimeters (somehow I get the impression that you forgott to square all your numbers... it happened to me regularly back in school).

so those 3.2258e9 cm^2 result in a "mere" 322,580 m^2. one square kilometer contains 1000x1000 meters (that's one million square meters!), resulting in the not quite so spectacular number of 0.32258 km^2. It's still a lot of space considering we want to pack it all into a ship, but it's managable (under the premises of this project, anyways).

 

[The Shadow]

Ouch... I'm bad :tiphat:

About a fifth of a mile, that is not bad at all compared to Australia. :embarrassed:

Throwing in the fact that these vials are 3D(like you mentioned) that makes it

500,000,000 cubic in.
x 2.54
x 2.54
x 2.54
= 8,193,532,000 cubic cm
/ 1000
/ 1000
/ 1000
= 8.193532 cubic km?

Watch me fail this time too.