Mass People Transport

Midoshi · 2008-05-15 11:43:34

Nuclear technology is inherently dangerous and several serious accidents have occured because of it. More accidents will happen.

Many energy technologies are inherently dangerous. That's inevitable when you manipulate the forces of nature on a large scale. Two examples:

There there have been hundreds if not thousands of boiler explosions over the past two hundred years, killing many thousands of people. Most of these occured in the 19th century, and as the technology improved it became safer, though never "perfectly" safe.

From prehistory to modern times an uncountable number of people have died from uncontrolled fires caused by the technology used to warm their homes. Sure, modern gas fired heating units are a lot safer than the open fires used in the medieval ages, but property and lives are still destroyed today.

The key is to develop a technology to the point were the risks are acceptable. A lot of people die because of technology that we often think of as "safe". The same applies to nuclear technology, though many people are so afraid of the power involved that they think it shouldn't be used at all.

The first few generations of nuclear reactor primarily had "active" regulation and meltdown reaction systems, that is, they were driven by electronics or mechanics that had to be commanded into operation. In contrast, the new reactors being developed today have "passive" safety mechanisms; they are "failsafe". For example, there is one Japanese design in which a lead shield surrounding the reactor will quickly melt and flood the core if it gets too hot, shutting it down, sealing it, and preventing any possibility of a meltdown.

That all said, I'm not particularly gung-ho about using nuclear tech. I just think it does have certain benefits and want to make sure it gets a fair representation.

Gregori · 2008-05-15 11:58:56

There are no fail safe Nuclear Technologies and if a serious accident does occur, the consequences can be dire and effect for generations. Boiler explosions don't disperse radioactive particles for miles and irradiate everything so its uninhabitable for centuries.

We should be phasing out Fission and prepare for Fusion power. Fusion reactors will produce far more power and don't suffer the problems of a run away chain reaction that causes a meltdown.

It is very likely that Fusion power will be achieved by the time colonizing outerspace is even possible.

ITER plans to achieve break even by 2030's. ESA and NASA are planning to land the first humans on Mars in the mid 2030's!

If ITER doesn't achieve it first, Robert Bussard's Polywell has a good shot at succeeding.

Midoshi · 2008-05-15 14:16:27

Be wary Gregori. Don't idolize fusion. The hydrogen, deuterium, lithium, and beryllium considered as fuel in current fusion designs are all highly explosive if there is a reactor breach. There's a lot of time and money going into making sure that an explosion doesn't occur, but we all know Murphy's Law...

Also remember that all currently plausible fusion methods produce massive amounts of neutrons. You're going to need shielding for this, and eventually that structure is going to become mildly radioactive from irradiation. If the reactor explodes, you're going to get radioactive schrapnel flying everywhere.

Do people worry about this? The engineers do, but it's not considered a show stopper. There are measures we can take to prevent or lessen the damage. Fission is the same. It's just there's a stigma attached to it.

Is fusion > fission? Yes, once we get there. But give poor fission a break.

GCNRevenger · 2008-05-15 14:36:26

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...
...There are no fail safe Nuclear Technologies and if a serious accident does occur, the consequences can be dire and effect for generations. Boiler explosions don't disperse radioactive particles for miles and irradiate everything so its uninhabitable for centuries.
We should be phasing out Fission and prepare for Fusion power. Fusion reactors will produce far more power and don't suffer the problems of a run away chain reaction that causes a meltdown.
It is very likely that Fusion power will be achieved by the time colonizing outerspace is even possible.

Nonsense, no technology is completely 100% fail safe, not cars, airplanes, chemical factories, buildings, medicine, food, none of them are completely safe! It is not possible to achieve 100% safety from anything, thats irrational and silly.

There is a finite, nonzero chance that you will be killed by a falling meteor before you finish reading this post. Its a definite risk. Or a tsunami. Or a or any number of things. But we don't live in caves do we? Its because some risk is acceptable, and well developed nuclear power plants are so safe that their risk is essentially no higher than any other big power plant.

Its time people stopped being irrational, childish fools and accepted the concept of non-zero risk and started acting like adults. With sufficient development, nuclear fission reactors are safe.

Now fusion power, we thought it would be 20 years until we got it to work about twenty years ago... but more importantly, even if we do get it to work on the ground by the time we are ready to start real expansion, is decades away from being a compact, light weight, and efficient power plant for space use. Its easy to make a nuclear fission reactor smaller, increase fuel enrichment and neutron reflector, but a fusion reactor is much more difficult as the bigger they are the more efficient they become.

Gregori · 2008-05-15 14:41:39

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...
...There are no fail safe Nuclear Technologies and if a serious accident does occur, the consequences can be dire and effect for generations. Boiler explosions don't disperse radioactive particles for miles and irradiate everything so its uninhabitable for centuries.
We should be phasing out Fission and prepare for Fusion power. Fusion reactors will produce far more power and don't suffer the problems of a run away chain reaction that causes a meltdown.
It is very likely that Fusion power will be achieved by the time colonizing outerspace is even possible.
Nonsense, no technology is completely 100% fail safe, not cars, airplanes, chemical factories, buildings, medicine, food, none of them are completely safe! It is not possible to achieve 100% safety from anything, thats irrational and silly.
There is a finite, nonzero chance that you will be killed by a falling meteor before you finish reading this post. Its a definite risk. Or a tsunami. Or a or any number of things. But we don't live in caves do we? Its because some risk is acceptable, and well developed nuclear power plants are so safe that their risk is essentially no higher than any other big power plant.
Its time people stopped being irrational, childish fools and accepted the concept of non-zero risk and started acting like adults.

Yeah, I know that. thats the whole point.

The consequences of a serious nuclear accident happen to be a lot more dire than a car, plane or normal power station breaking down.

GCNRevenger · 2008-05-15 14:46:08

Yeah, I know that. thats the whole point.
The consequences of a serious nuclear accident happen to be a lot more dire than a car, plane or normal power station breaking down.

But this is the thing, with enough development the risk of a disaster will be acceptable. I believe that the risk is acceptable now with modern designs, like the Westinghouse AP1000 design.

The design is 20% as complicated as previous reactors, and there are valves holding the moderator in the core and coolant water in gravity-fed tanks. If the worst possible thing goes wrong, if all control and power is lost and everyone at the plant is abducted by aliens, and the pressure vessel of the reactor fails...

...then the multi-redundant valves release, since without power they don't hold shut, moderator is dumped, the nuclear reaction stops, and the pressure is relieved. Plus the emergency coolant is dumped under the force of gravity to cool the core. And even if the core did leak, the radioactive material would be contained in the thick steel containment building.

And don't get me started about how safe the pebble-bed or Uranium Hydride reactors are. Modern reactors are so far removed from the stupid primitive Chernobyl design that it is dishonest as well as ignorant to compare them.

Gregori · 2008-05-15 15:17:53

Yeah, I know that. thats the whole point.
The consequences of a serious nuclear accident happen to be a lot more dire than a car, plane or normal power station breaking down.
But this is the thing, with enough development the risk of a disaster will be acceptable. I believe that the risk is acceptable now with modern designs, like the Westinghouse AP1000 design.
The design is 20% as complicated as previous reactors, and there are valves holding the moderator in the core and coolant water in gravity-fed tanks. If the worst possible thing goes wrong, if all control and power is lost and everyone at the plant is abducted by aliens, and the pressure vessel of the reactor fails...
...then the multi-redundant valves release, since without power they don't hold shut, moderator is dumped, the nuclear reaction stops, and the pressure is relieved. Plus the emergency coolant is dumped under the force of gravity to cool the core. And even if the core did leak, the radioactive material would be contained in the thick steel containment building.
And don't get me started about how safe the pebble-bed or Uranium Hydride reactors are. Modern reactors are so far removed from the stupid primitive Chernobyl design that it is dishonest as well as ignorant to compare them.

I don't think people will take to well to the idea that them being irradiated and there entire area becoming uninhabitable is an acceptable risk!

the consequences of an accident are far too serious to be left to chance. because nothing can be made completely fail safe, that means an accident happening is merely a matter of when.

a design that is 20% more complicated just means there are more things that can potentially go wrong!!

Midoshi · 2008-05-15 16:17:45

It occurs to me that many hundreds of nuclear submarines and ships have been operated for the equivalent of many thousands of "reactor years" during the past half a century. There have been a few engine incidents, to be sure, but the technology has proven safe enough that we continue to operate them on a large scale.

Gregori · 2008-05-15 16:52:20

It occurs to me that many hundreds of nuclear submarines and ships have been operated for the equivalent of many thousands of "reactor years" during the past half a century. There have been a few engine incidents, to be sure, but the technology has proven safe enough that we continue to operate them on a large scale.

They're a disaster waiting to happen. there have been a few small scale incidents and there very probably will be a serious one soon enough. Once this occurs, there will be devastating consequences that will be out of our control. the cat will be out of the bag!

Rather than wait around for an accident to happen, we should be phasing fission power out and getting ready for safer sources like fusion.

anyway, lets get back on topic - mass people transport!

cIclops · 2008-05-15 21:56:00

Rather than wait around for an accident to happen, we should be phasing fission power out and getting ready for safer sources like fusion.

anyway, lets get back on topic - mass people transport!

Phasing out fission power before anyone even knows when fusion power will be available would be a disastrous policy.

Yes, mass people transport in space - before this can be sensibly discussed, where are these people going and why?

Gregori · 2008-05-16 08:05:21

Yes, mass people transport in space - before this can be sensibly discussed, where are these people going and why?

Okay, good question.

If we wanted to establish large colonies or industrial operations in space, we will need to be able to send more than 6 people at a time. We need to send people in bulk.

We would also want to be able to ferry goods and passengers around the solar system on pretty regular intervals to maximise their economic benefit and make colonies viable. There should be constant traffic between the locations to offset the high cost of the hardware.

The places I imagine these people going would be The Moon, Mars, Phobos, Deimos, NEO's, Ceres, Vesta and the rest of the Asteroid Belt!!

Other possible destinations would be space stations and habitats, Venus and Mercury - If those become technologically possible to settle without 'terraforming'

Ultimately it makes a lot of sense to seperate the Cargo and Passenger aspects of space. Both of these can probably be automated. I think economies of scale is the way to go with space industry and settlement.

SpaceNut · 2008-05-16 15:49:33

For me the defining of how many is a mass number to transport is just half of the question that needs to be asked as the other part is to where it needs to go to and from each destination.

Gregori · 2008-05-16 16:48:44

For me the defining of how many is a mass number to transport is just half of the question that needs to be asked as the other part is to where it needs to go to and from each destination.

lets say a very minimal for mass transport would be 12 people. thats 4 times the amount of a soyuz craft and a little under twice the shuttles capability.

We would want to be transporting as much as passenger plane, ocean liner or bus/train, around 100+ people!

SpaceNut · 2008-05-16 19:56:48

I like 12 as a number, now it is time to indicate how long they will be in the ship from beginning of launch to its return and not at a destination haven.

Since each crew member needs water, oxygen, food and a space suit for use these items are just the beginning thou to rationalizing the size of the transport.

I would love to convert the shuttle for a once every 6 months to orbit with crews of 50 or more as it could be converted to do that task but at what budget dollars should we target the transport of such numbers of crew for.

Gregori · 2008-05-17 07:50:52

I like 12 as a number, now it is time to indicate how long they will be in the ship from beginning of launch to its return and not at a destination haven.
Since each crew member needs water, oxygen, food and a space suit for use these items are just the beginning thou to rationalizing the size of the transport.
I would love to convert the shuttle for a once every 6 months to orbit with crews of 50 or more as it could be converted to do that task but at what budget dollars should we target the transport of such numbers of crew for.

Could the Shuttle Lift 50 people into LEO and not kill them?

If it can, I'd be interested in this or a similar vehicle being used for mass people transport!

Well, lets just say that the destination is Mars. Chemical Rockets can get there in around 5-6 months at ideal times.

Because this is Mass Passenger transport, Its not neccesarily true that they return in the same vehicle. This isn't for mere exploration missions. I'm envisioning this for transporting people to permanent colonies. There will be several such vehicles going to and fro and some people will be going permanently.

I heard a rumour that a 200 MW VASIMR could cut down the journey to 39 days. The problem is a power source. It would require a Fission/Fusion reactor or one hell of a huge Solar Array.

A way I thought of over coming this would be to use a powerful laser to beam power at a smaller array. This would greatly reduce the mass of the vehicle. I don't think its possible quite yet though.

JoshNH4H · 2008-05-17 12:09:13

no, it probably isn't. Basides, Vasimr couldn't really have that high of a thrust. But since, as someone at this forum (I forget who, I apologize) said:
"LEO is half way from here to anywhere"

So I think we should work on LEO for the moment. How about an air propelled NTR?

Gregori · 2008-05-17 17:06:42

no, it probably isn't. Basides, Vasimr couldn't really have that high of a thrust. But since, as someone at this forum (I forget who, I apologize) said:
"LEO is half way from here to anywhere"
So I think we should work on LEO for the moment. How about an air propelled NTR?

The guys who are working on VASIMR claim that if it could be supplied with 200 MW powersource, it could get to Mars in 39 days. If an appropriate powersource can be found, it is very doable! I believe a small scale VASIMR will be tested in space in 2010 (I'm not incredibley sure)

An NTR upperstage is also probably doable, but nuclear tech is going to raise all the obvious concerns.

GCNRevenger · 2008-05-17 17:36:59

The problem with VASIMR for manned use is that no power plant of that output is available that doesn't weigh too much, except the exotic vapor-core fission reactors.

I'm all for fission engines in space, but using them in the atmosphere is a bad idea. It gives only limited benefit anyway, air-breathing chemical is the way to go, something like the Saenger-II/Shuttle LSA or maybe even a single-stage like the X-30 NASP/Reaction Engine's Skylon.

Gregori · 2008-05-17 18:18:23

I'm all for fission engines in space, but using them in the atmosphere is a bad idea. It gives only limited benefit anyway, air-breathing chemical is the way to go, something like the Saenger-II/Shuttle LSA or maybe even a single-stage like the X-30 NASP/Reaction Engine's Skylon.

Yeah, your right. Its probably a very bad idea.

If you take away the issue of supplies (lets just say they're already waiting there on the Moon or in LEO). Would it be possible to launch 100 people (like a passenger plane) in a specialized passenger vehicle on top of an Ares V?
They would have enough water, air and food to survive the trip to LEO.

Would that be to heavy?

GCNRevenger · 2008-05-17 20:33:22

Mass transport is never going to happen with expendable vehicles of any sort. Something reusable is absolutely necessary, especially when it will be packed with expensive life support and escape equipment. Furthermore, a big expendable cargo rocket consciously trades high reliability for increased payload efficiency since it does not need to carry people. A reusable vehicle on the other hand has to be reliable, otherwise it won't come back enough times to make it worthwhile.

Gregori · 2008-05-17 21:50:47

For the time being, all we have is disposable space craft!!
It would be a very expensive way to mass transport people - but we know its feasible!

I heard that some version of the Russian Energia was going to be fully reusable. All stages and boosters would be able to glide back down to Earth using wings/parachutes. If that were true - its a pity they stopped that program.

Although, the same kinda idea was implemented in the Shuttle program, and it didn't really make it cheaper.

Grypd · 2008-05-18 05:52:35

For the time being, all we have is disposable space craft!!
It would be a very expensive way to mass transport people - but we know its feasible!
I heard that some version of the Russian Energia was going to be fully reusable. All stages and boosters would be able to glide back down to Earth using wings/parachutes. If that were true - its a pity they stopped that program.

The reason that we are still using disposable space craft is that they are a tried and tested technology and one where we do not have to put a lot of money into designing new hardware. It is literally a chicken and egg scenario we do not need to develop cheap RLV access to space until we need to put a lot of people routinely (Read Daily) into space and we can't put a lot of people into space until we have cheap RLV.

GCNRevenger is correct that the cheapest RLV is a single stage craft when it comes down to routine access but we do not have that technology now and it will be very costly to develop. Im an advocate for a TSTO RLV where we get the advantages of a better mass fraction and one where we can still get quick turn around as we keep both aircraft as that is what the lower stage is. Examples of such craft are Saenger 1 and Bristol Spaceplanes Spacebus.

The idea for mass population movement is to get as close to Airline use out of these craft as possible. If we can do that it will drastically cut the cost of people to orbit and of course cargo too. Of course it still comes down to what do we need that many people moving in and out of orbit daily for.

GCNRevenger · 2008-05-18 11:01:24

For the time being, all we have is disposable space craft!!
It would be a very expensive way to mass transport people - but we know its feasible!
I heard that some version of the Russian Energia was going to be fully reusable. All stages and boosters would be able to glide back down to Earth using wings/parachutes. If that were true - its a pity they stopped that program.
Although, the same kinda idea was implemented in the Shuttle program, and it didn't really make it cheaper.

And for the time being, we don't need mass people transport either. Furthermore, if it is very expensive, then it is not feasible, mass people transport has to be cheap. A 50 seat megacapsule on top of Ares-V would cost around a billion a launch easily, which makes for twenty million dollars a ticket, which is just not that good. You could only launch a few of those a year anyway most likely.

We also can't fall for the "gaetanomaronian" aversion to development costs: since we have to have a reusable vehicle thats cheap to fly, it will undoubtedly cost a lot of money to develop, which we will just have to pay as the price of doing business.

As far as Energia, or for that matter any low-tech multistage vertical launch rocket, just takes too much trouble to launch and would have too low of a reliability. Something with wings, probably launched horizontally, is all but definitely the way to go: less thrust required, easier to abort, efficient air breathing engines, much much easier to recover.

cIclops · 2008-05-18 11:20:36

Yep. And to complete the system it would rendezvous with a reusable transit vessel that would be refueled by lunar/Martian ISRU supplied by reusable tankers.

Reusable from Earth to LEO, then space based fuel the rest of the way again and closed life support. Should be quite game for passengers guessing who previously ate their food. For Mars EDL/ascent again a reusable craft would be needed.

Of course all this is at least one more generation of space craft along or perhaps two.

Gregori · 2008-05-18 15:17:49

I think one of the first pieces of infrastructure we should put on the Moon should be a large LOX plant and a reusable refueling vehicle.

If it isn't used for refuleing vehicles, It would be atleast a good off-world source of oxygen for breathable air!

Tapping a large off-world supply of water that is close to us would also be helpful.

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