Mass People Transport

Gregori · 2008-05-10 06:45:03

To make any colonization effort practical or even plausible, I think you would need a dedicated method to transport lots of people from one location to the next - kinda like a space bus

I imagine that in the future there will be dedicated cargo carriers and dedicated ferries from tranporting people. ATM, one craft carries a limited amount of cargo, scientific instruments and 2-7 astronauts. Obviously that not a runner for space colonization.

On Earth, Cargo and Public Transport tend to seperated!

I'd like to throw open this thread to wild speculation as what could acheive that!

I'd like to know what are the difficulites?

How do we transport 20 or 100 people across space?

cIclops · 2008-05-10 06:59:58

This is a big subject, how many difficulties do you want?

Indeed, separating cargo and people makes a lot of sense, that's one of the main reasons for splitting the new system into two parts. A smaller, safer system for people, which makes it expensive, and a cheaper larger system for cargo.

The BIG problem is propulsion. Currently LOX/LH2 technology is the best available yet it's too inefficient to propel the enormous quantity of mass needed to transport and sustain more than a few people and their luggage to Mars.

20-100 people consume a huge amount of water, food and air, so a closed life support system will be necessary. A fast transporter would be helpful too to reduce the exposure to inspace radiation whereas cargo can take its time. More speed and mass both need more propulsion.

JoshNH4H · 2008-05-10 07:30:06

I would suggest a fission fragment rocket in which Uranium/NILFiR fuel is magnetically suspended outside the back of the spacecraft. There will be a sail, to rebound all of the particles going towards the spacecraft. Isp 30,000,000. It can accellerate 500 MT at 1 G with a 5 MWt reactor.

Gregori · 2008-05-10 07:33:13

I wonder if it would help reduce consumable supplies if we could put humans into hibernation or a state of torpor?

cIclops · 2008-05-10 08:30:32

Do you mean force them to watch primary debates?

Gregori · 2008-05-10 09:11:14

lol

louis · 2008-05-10 14:26:40

I'd like to throw in some ideas from other threads.

I think part of the solution will be ISRU on the moon, so we manufacture both rocket fuel and a simple "space bus" housing maybe 30 people. The space bus might be assembled in lunar orbit following a number of launches by a dedicated vehicle. Once assembled the space bus is towed from lunar orbit to earth orbit.

We then launch the Mars lander from earth. The lander - which all the complicate machinery on board is attached to the space bus (which will be attached to the front of the lander). When in Mars orbit, the space bus and lander detach and people are taken down five at a time say. There will be a number of landers already on Mars and rocket fuel will be being produced on Mars. So a number of landers will go up and meet the "space bus" and bring people down over the course of say 2 to 3 days.

Once launched, Mars landers never return to earth, they only ever enter low earth orbit. People return to earth in two person "Pods". People are transferred to the space bus from dedicated stripped down personnel launch vehicles.

Gregori · 2008-05-10 17:40:46

We'll need a craft with the ability to launch atleast 20 humans off the Earth's surface in one go, probably more though.

Seeing the large payloads capable by the Ares I+V, I don't think propulsion is that much of an issue. Its keeping all those people alive for the transit. That requires a lot of consumables.

If we could find a way to put these people into hibernation-like state for the journey, it could reduce the amount of food needed. Water and Oxygen can probably by recycled. I think we would need some very powerful drugs and life support machines to achieve this.

Putting the crew into an extended deep sleep might mitigate some of the psychological problems of the journey.

I think producing some rocket fuel and supplies on the moon could help.

louis · 2008-05-10 19:06:53

I agree with you Gregori about the importance of ISRU on the moon. If I've got this right, it doesn't take a lot of energy to propel a large craft with lots of consumables on board from earth orbit to Mars orbit. I think if we can grow a lot of the food on the Moon, that will make the problem more tractable.

Deep sleep technology will at some point become a reality (we already have medical procedures where people have been kept alive through deep freezing). However, I think we better assume that for the foreseeable future our pioneers will be fully conscious - and hungry.

Regarding water and air, I've found it difficult to get accurate figures on recycling. I mean 90% recycling doesn't mean much unless you know over what time cycle. Figures can be rather ambiguous.

cIclops · 2008-05-10 23:21:04

Seeing the large payloads capable by the Ares I+V, I don't think propulsion is that much of an issue. Its keeping all those people alive for the transit. That requires a lot of consumables.

A single Ares I will only be able to launch six people into orbit and two Ares V are needed to transport them to Mars! It would be a one way trip as even two Ares V cannot transport the return vehicle. So 24 people, one way to Mars would effectively require 4 x Ares I and 8 x Ares V. When they arrived at Mars there would be nowhere for them to live and nothing to breathe, drink or eat unless Habitats and supplies had been established. Each six person Habitat would require 2 more Ares V launches, this would provide supplies for about 18 months.

Gregori · 2008-05-11 09:14:23

Seeing the large payloads capable by the Ares I+V, I don't think propulsion is that much of an issue. Its keeping all those people alive for the transit. That requires a lot of consumables.
A single Ares I will only be able to launch six people into orbit and two Ares V are needed to transport them to Mars! It would be a one way trip as even two Ares V cannot transport the return vehicle. So 24 people, one way to Mars would effectively require 4 x Ares I and 8 x Ares V. When they arrived at Mars there would be nowhere for them to live and nothing to breathe, drink or eat unless Habitats and supplies had been established. Each six person Habitat would require 2 more Ares V launches, this would provide supplies for about 18 months.

With currently planned crew vehicles, thats true.

If we could effectively treat the crew like cargo, a vehicle could be designed to carry far more people than the current limits. This would require a closed cycle for water and air and sometype of induced hiberation state to lower metabolism.

The whole gist of the idea is for vehicles that can easily deliver lots of people to an already established colony with supplies already set up there.

JoshNH4H · 2008-05-11 09:38:28

I blieve an atmosphere 80% xenon, 20 % oxygen would be anaestetic.

Gregori · 2008-05-12 06:17:08

I blieve an atmosphere 80% xenon, 20 % oxygen would be anaestetic.

would that lower the metabolism of the passengers?

Like putting them into a deep sleep could avoid some of the problems of 'cabin fever' in a six month + journey through mostly featureless space but we're trying to lower their food consumption to an absolute minmal - like hibernating animals do on Earth.

Another idea I have been toying a round with is a Large Modular Vehicle that does regular trips between Mars and Earth Orbit, but doesn't land on either planet.

Smaller craft launched of Ares type rockets would bring people up to it over a period of a few days from the surface of either planet.

These small people carrying craft would not need to bring many supplies up, just the people.

A seperate supplies craft would stock up the ship for a six month journey.

The smaller craft would serve would be used to depart and land on the surface of either planet (like Soyuz capsule)

The smaller craft would also be used to extend the living space of the over all vehicle.

This ship

Antius · 2008-05-13 06:13:51

I blieve an atmosphere 80% xenon, 20 % oxygen would be anaestetic.
would that lower the metabolism of the passengers?
Like putting them into a deep sleep could avoid some of the problems of 'cabin fever' in a six month + journey through mostly featureless space but we're trying to lower their food consumption to an absolute minmal - like hibernating animals do on Earth.

Another idea I have been toying a round with is a Large Modular Vehicle that does regular trips between Mars and Earth Orbit, but doesn't land on either planet.
Smaller craft launched of Ares type rockets would bring people up to it over a period of a few days from the surface of either planet.
These small people carrying craft would not need to bring many supplies up, just the people.
A seperate supplies craft would stock up the ship for a six month journey.
The smaller craft would serve would be used to depart and land on the surface of either planet (like Soyuz capsule)
The smaller craft would also be used to extend the living space of the over all vehicle.
This ship

How about a dedicated Big Dumb Booster Rocket to get them into space in the first place? Let me see: for a 1000tonne-to-LEO rocket:

Mass of person = 100kg, mass of cabin structure = 100kg/person, mass of life support = 50kg/person:

A BDB with 1000tonne to LEO lift capacity could life 4000 people in space. Lift cost = $500/kg x 250kg = $125,000.

Average wages in Solar Satellite Construction Industry are $250,000/year, so the transport to orbit could be payed off by a mortage of $150,000 spread over 3 years.

Gregori · 2008-05-13 06:43:04

How about a dedicated Big Dumb Booster Rocket to get them into space in the first place? Let me see: for a 1000tonne-to-LEO rocket:
Mass of person = 100kg, mass of cabin structure = 100kg/person, mass of life support = 50kg/person:
A BDB with 1000tonne to LEO lift capacity could life 4000 people in space. Lift cost = $500/kg x 250kg = $125,000.
Average wages in Solar Satellite Construction Industry are $250,000/year, so the transport to orbit could be payed off by a mortage of $150,000 spread over 3 years.

I can see how that would work on paper, but nobody has yet built such a rocket yet. It hasn't been proven. NASA is struggling to build something that can even lift 125 tonnes into LEO. If such a tech is developed that can lift a 1000 tonnes, cool!!! I'm for doing this on a big industrial scale.

For the time being, I'm thinking more about how the current Ares tech could be modified to launch people like cargo into LEO, on a kinda space bus. These people caspules would all dock with a ship that ferries 100's of people to Mars but never lands.

JoshNH4H · 2008-05-13 14:21:07

assuming antius' figures are correct, Ares V could lift 50 people with a cost of ??????????? total.

GCNRevenger · 2008-05-14 17:12:06

If we're thinking colonization, no "big dumb booster" launch vehicle will be cheap or safe enough. A true RLV like the Saenger-II or X-30 NASP is the only current option.

Don't gloss over propulsion when we do get the people up there, simple chemical rockets don't have the efficiency to keep transit times low enough for an average person to stay in good shape physically or mentally. A gas core nuclear rocket would be a nice option, with high efficiency and high thrust with a minimum of radically new technology. It would also give abort-to-port capabilities in the event of trouble.

GCNRevenger · 2008-05-14 17:27:56

I would suggest a fission fragment rocket in which Uranium/NILFiR fuel is magnetically suspended outside the back of the spacecraft. There will be a sail, to rebound all of the particles going towards the spacecraft. Isp 30,000,000. It can accellerate 500 MT at 1 G with a 5 MWt reactor.

Five hundred metric tonnes at 1G with a five megawatt reactor? Nonsense, thats a huge acceleration from such a small amount of power.

dryson · 2008-05-14 17:56:43

what about using an ION engine? The consumption of fuel would make the venture to Mars less costly then other forms of propulsion. The only question is will the engine provide enough thrust to propell the ship to Mars in a feasible amount of time?

GCNRevenger · 2008-05-14 19:43:58

what about using an ION engine? The consumption of fuel would make the venture to Mars less costly then other forms of propulsion. The only question is will the engine provide enough thrust to propell the ship to Mars in a feasible amount of time?

No, it won't.
And the best fuel for ion engines - Xenon gas or Cesium metal, aren't available anywhere in the solar system in sufficient quantity to sustain large-scale ion drive operations.

Gregori · 2008-05-15 08:22:06

If we're thinking colonization, no "big dumb booster" launch vehicle will be cheap or safe enough. A true RLV like the Saenger-II or X-30 NASP is the only current option.
Don't gloss over propulsion when we do get the people up there, simple chemical rockets don't have the efficiency to keep transit times low enough for an average person to stay in good shape physically or mentally. A gas core nuclear rocket would be a nice option, with high efficiency and high thrust with a minimum of radically new technology. It would also give abort-to-port capabilities in the event of trouble.

People are generally pretty scared of being irradiated, nuclear accidents etc.

If my figures are correct on this, It takes around 5-6 months to get to Mars with current chemical rocket technology. People have stayed on the ISS for that long, so it can be done without too much mental or physical damage.

cIclops · 2008-05-15 08:27:54

If my figures are correct on this, It takes around 5-6 months to get to Mars with current chemical rocket technology. People have stayed on the ISS for that long, so it can be done without too much mental or physical damage.

ISS orbits within the Earth's magnetosphere and has significant protection from the solar wind and GCR. In an emergency, ISS crew can use their Soyuz lifeboat and be safely on Earth within about an hour. They are also in almost continuous real time communication with people on Earth, as well as seeing the planet in great detail just below them. Crew in transit to Mars and back will be in a far more stressing and dangerous environment.

Gregori · 2008-05-15 08:48:38

ISS orbits within the Earth's magnetosphere and has significant protection from the solar wind and GCR. In an emergency, ISS crew can use their Soyuz lifeboat and be safely on Earth within about an hour. They are also in almost continuous real time communication with people on Earth, as well as seeing the planet in great detail just below them. Crew in transit to Mars and back will be in a far more stressing and dangerous environment.

Undoubtedly its dangerous, but we don't exactly have a lot of options here.

I don't think we're going to sea a nuclear ship in space (Unless it was a fusion based craft) An accident would have pretty bad consequences.

If space radiation turns out to be not as big a threat as predicted or if the crew can be shielded from it, I think the lenght of the journey is not that problematic.

People have went on long ocean journeys with NO communication with home and NO lifeboats!!

I'm rather fond of the idea of putting people into a hibernation state for such journeys to cut down on food supplies and avoid cabin fever etc etc

We don't have the drugs and machines to do that yet however.

GCNRevenger · 2008-05-15 09:18:47

If we're thinking colonization, no "big dumb booster" launch vehicle will be cheap or safe enough. A true RLV like the Saenger-II or X-30 NASP is the only current option.
Don't gloss over propulsion when we do get the people up there, simple chemical rockets don't have the efficiency to keep transit times low enough for an average person to stay in good shape physically or mentally. A gas core nuclear rocket would be a nice option, with high efficiency and high thrust with a minimum of radically new technology. It would also give abort-to-port capabilities in the event of trouble.
People are generally pretty scared of being irradiated, nuclear accidents etc.
If my figures are correct on this, It takes around 5-6 months to get to Mars with current chemical rocket technology. People have stayed on the ISS for that long, so it can be done without too much mental or physical damage.

It can be done, but it shouldn't be done, nor is it necessary. And people need to get over their fear of nuclear energy, their fear is unjustified and stupid. Stupid people probably won't take the risk of a Mars flight nuclear or no.

Gregori · 2008-05-15 09:29:42

It can be done, but it shouldn't be done, nor is it necessary. And people need to get over their fear of nuclear energy, their fear is unjustified and stupid. Stupid people probably won't take the risk of a Mars flight nuclear or no.

Its not stupid and its pretty justified. Nuclear technology is inherently dangerous and several serious accidents have occured because of it. More accidents will happen.

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