Project High Velocity Interplanetary Passenger Spacecraft

[T.Neo]

(edit: click image to enlarge)

1- Engines. Mounted forward of the rest of the ship on booms to save mass. Thrust stream is angled outward 2 degrees to prevent damage to the ship.

2- Fuel tank. Holds fuel- not much else to it.

I'm not so sure of the design of the fuel tanks at the moment, so I may change them.

3- Reflective shields. Reflect thermal radiation from the engine exhaust.

4- Tensionary truss. Having major structural aspects of the vehicle in tension reduces mass. It could be a tether, but a truss adds rigidity for rotational and translational manoeuvres.

5- Docking node. Able to accomodate two DG type vessels or two XR2s.

6- Transfer tunnel. Allows transfer from the docking node to the habitation module. Also acts as a truss.

7- Habitation module. Able to house 14 people.

The spacecraft has a maximum operational velocity of around 200 km/s, and a overall Delta v of around 500 km/s. Maximum acceleration while under thrust will be 1-1.5 G.

The spacecraft is designed to spin along the X axis while in the cruise phase of the flight. This produces artificial gravity, and is known as a "tumbling pidgeon" arrangement. The Orion spacecraft was designed to generate artificial gravity this way, and an (unintentional) example can be seen in 2010, when the Discovery spins end-over-end. Usually this incurs odd arrangements of crew and cargo (the direction of acceleration during thrust and the direction of acceleration during spin are opposite eachother). However, here the direction of acceleration during thrust and spin is the same, which is a benefit of having the engines in front of most of the spacecraft structure- the engines and fuel tanks act as a counterweight to the habitation module.

Cheers.

 

[Izack]

So we're finally getting that puller arranged interplanetary ship. Nice work, T.Neo, on a well thought out and insofar well executed design! :thumbup:

It never occurred to me before that a puller arrangement was ideal for a tumbling pigeon. It makes sense in hindsight, though.

 

[Moach]

Nice! i was already itching to see that thing come to life!

i hope you decide to make a VC for it :thumbup:
something like this would be super-mega-awesome if it had a custom DLL


i too agree that a puller design for a tumbling ship is a very fitting concept! the center truss can be much lighter (or even cables?), and not having to rearrange everything in the cabin before any course adjustments is a great relief for spacemen aboard - also, it means more stowage space and all...

solar panels could be placed along the sides of the central truss... if you point the x-axis towards the sun, they should not lose efficiency from spinning



this concept is so cool! we're probably going to mars on something similar, from what i've heard

 

[Andy44]

Solar panels are not necessary, since this thing is presumably nuclear-powered.

In the interests of realism, I would suggest more realistic auxillary craft or landers in place of DG-type fantasy vehicles.

Overall, a pretty cool idea. Maybe you could make it fold up so it fits inside a heavy launch fairing?

Keep up the good work.

 

[jedidia]

In the interests of realism, I would suggest more realistic auxillary craft or landers in place of DG-type fantasy vehicles.

considering the thrust power of this baby, DGIVs will fit in quite well, me thinks.

 

[mc_]

Overall, a pretty cool idea. Maybe you could make it fold up so it fits inside a heavy launch fairing?

Excellent idea :thumbup:
I suggest, something like Kulch's Mir-2 Titan module would be nice for this case.

 

[Moach]

if the design went in ways of removing the central docking thing, perhaps instead of a truss, the ship could be bound by a set of cables, which would be spooled in upon launch, then unwound once in orbit...

if the RCS thrusters were angled inwards just a bit, they could keep the cable taut during rotation maneuvers as well...
and maybe a set of jets positioned for the sole purpose of tightening the cables during maneuver...
i think the additional expense of attitute propellant is minimal, given the advantages of a cable design vs. a hard truss

much lighter-weight and quite a "flexible" design

 

[Sky Captain]

I'm wondering how a puller type ship would handle an engine out event. If one engine fails then thrust becomes imbalanced and to balance it you would have to point the remaining engine in a way that exhaust vector goes through the center of mass of the vessel with all the implications of hot plasma striking the structure.

 

[Moach]

good point...

may i suggest, instead of two thrusters, it would be more fail-safe to have a series of 6~8 smaller ones...

then, if any one engine goes kaput, just switch off the opposite one and the ship remains stable :hmm:

 

[T.Neo]

i hope you decide to make a VC for it

Yep- a VC has been in the works for some time.

this concept is so cool! we're probably going to mars on something similar, from what i've heard

Mars, Venus, anywhere out to Jupiter really. But I suppose with refueling in the asteroid belt or at Jupiter, trips to the outer system could be made.

I must admit though, that the trips I have done up to now (using TransX and the Bullet spacecraft) at Dvs of around 200 km/s (both to Venus) have not been satisfactory. Perhaps such trajectories require the correct launch window, or I'm not doing it right.

Solar panels are not necessary, since this thing is presumably nuclear-powered.

Yep. It will have radiators, I just haven't meshed them yet.

Perhaps solar panels could be useful perhaps as a backup system.

In the interests of realism, I would suggest more realistic auxillary craft or landers in place of DG-type fantasy vehicles.

Oh no, they don't have to be Deltagliders, they can really be anything in that mass and dimension range. I won't be doing auxillary craft to go with this ship specifically, though- nor will I be doing a DG-type vehicle.

Are there any good multipurpose planetary lander addons?

Maybe you could make it fold up so it fits inside a heavy launch fairing?

I was originally thinking strict on-orbit construction, but the individual segments would still have to be lofted by a relatively large vehicle.

considering the thrust power of this baby, DGIVs will fit in quite well, me thinks.

If it helps I've made the engines quite large and given them magnetic nozzles.

She should be at least better than the DG in terms of turning the nozzles into X-ray radiating plasma...

i think the additional expense of attitute propellant is minimal, given the advantages of a cable design vs. a hard truss

The truss isn't all that massive. The accelerations from the RCS are rather low, perhaps a hundredth of a G.

A tether would certainly be less massive, but IMO the ridigity of a truss outweighs the mass penalty- in certain situations continuously firing the RCS to keep rigidity (such as docking with another spacecraft using the aft port) would not be desired.

I'm wondering how a puller type ship would handle an engine out event.

Well, it probably wouldn't. The only way would be attempting to prevent an engine-out event, perhaps with redundant systems. Spare components and repair supplies could be carried near the center of mass, or there could be multiple engines per side that could take up the slack should an engine fail. (edit: Moach beat me )

Perhaps a sort of "Coast Guard" would be advantageous- flying out of the solar system at 200km/s is not a good place to be. :suicide:

 

[CigDriver]

Well, it probably wouldn't. The only way would be attempting to prevent an engine-out event, perhaps with redundant systems. Spare components and repair supplies could be carried near the center of mass, or there could be multiple engines per side that could take up the slack should an engine fail. (edit: Moach beat me )

Perhaps a sort of "Coast Guard" would be advantageous- flying out of the solar system at 200km/s is not a good place to be. :suicide:

Sounds like a great use of UMMU Action areas

 

[Zachstar]

Multiple engines are a must. Compact fusion reactors in each would provide the ISP and thrust needed for massive speed and quick trips while providing a means of return in events of failure.

TransX seems wonky when dealing with extremely fast transfers. But assuming you have the ISP to do so I suggest just burning out of orbit in general direction and speed of target. then doing a refinement later. Problem with this is you have to burn at say 1G or more in order to not end up in a situation of an extremely difficult to plan encounter.

VASIMR 39 days to mars involves a very complex spiral out and in that basically involves it spending almost the entire time in the burn.

 

[Sky Captain]

I think 6 engines should be OK. Then you could have 2 engines break down and still make it back home.

 

[Moach]

there's yet another approach to a tractor engine that no-one has proposed...


it's a sort of propulsion-less engine - no, it ain't sci-fi - and yeah, Newtown would be turning in his grave, but Einstein wouldn't...

it's called the EmDrive

the idea is that microwaves from a magnetron similar to those used in your kitchen oven would flood the engine chamber, which is shaped is a manner that exploits the relativistic effects of the near-lightspeed velocity these waves travel in as they bounce inside it's walls

from a newtonian point-of-view, this violates rule n° 3, and the engine is therefore, a glorified paperweight....

but as far as my understanding of the relativity principles employed here goes, what happens is that an open system is created as the waves bounce off the large plate capping the cone-shaped chamber, which receives a greater amount of radiation pressure than the opposing smaller plate... therefore, even though no waves are allowed to leave the engine - thrust is generated :blink::uhh::OMG:

there have been, as you can imagine, a boatload of critics on this concept... it is, in theory, violating what has long been perceived as a fundamental law of nature

but the website claims a prototype has been able to generate a measurable amount of thrust (using not much power than a conventional microwave oven)


now, imagine the power of that thing being fed by a regular nuke...

this not only solves the shooting-own-foot problem of a tractor ship, but IMO, qualifies as SHEER AWESOME:thumbup:


as long as you believe it could work:hmm:

 

[Sky Captain]

The Emdrive seems like something from scifi. Their FAQ section claims a static thrust of 30 KN/kw could be achieved which looks extremely optimistic, but as the vehicle accelerates thrust would rapidly drop which seems kinda weird and is bad news for high energy interplanetary missions.

Also if it is as promising as it sounds I'd suspect much more incentive to develop this technology especially since basic components to build that engine are relatively straightforward. Now it is only small company working on it.

 

[Moach]

i too find it strange that this hasn't been getting the attention due to something THAT revolutionary...

perhaps it's because ppl don't take it seriously, or maybe ppl don't take it seriously because of that?

or perhaps both... and a major breakthrough in propulsion is being cast aside by lack of someone being the first to give it some credit

or perhaps it is just as impractical as it's being claimed to be...



now, another approach... why not using a large parachute-like sail and simply shooting nuclear-powered microwaves against it?... the waves would bleed off after bouncing against the sail applying a large amount of radiation pressure on it...

would that not be like solar wind "on steroids"? or is there some principle dictating why that's impossible?

 

[Izack]

The self propelled sail sounds about as practical as a sailboat with a giant fan

If this ship is intended to have a high ISP, I don't think a sail is the way to go anyway. May as well use the reactors to power conventional (a hundred years from now, anyway) engines.

 

[Spike Spiegel]

Wouldn't the microwaves (or lasers, or any other sort of directed energy) need to be fired from another location? Maybe that's what you're talking about, I don't know. You couldn't fire them from the ship into the ship's "sail". Wouldn't that be like putting a fan on a sailboat and expecting it to move your boat anywhere?

(Whoops! Izack beat me to that one!)

 

[T.Neo]

TransX seems wonky when dealing with extremely fast transfers. But assuming you have the ISP to do so I suggest just burning out of orbit in general direction and speed of target. then doing a refinement later. Problem with this is you have to burn at say 1G or more in order to not end up in a situation of an extremely difficult to plan encounter.

I have high ISP but I don't have unlimited Dv.


Would IMFD be better in terms of navigation at high velocities? I'd prefer to have the user use either- some prefer the manual aspects of TransX, while others prefer the straightforwardness of IMFD (though I must admit I've never used it).

I think 6 engines should be OK. Then you could have 2 engines break down and still make it back home.

It isn't like these engines are all that unreliable- I'd expect a single engine out to be a worst case scenario. Conventional compressional designs and even real vehicles have had far less redundancy than this. In the end more and more engines will just add to the overall complexity, which is not desirable.

Perhaps it can be compared to a 737- a 737 has two engines (the complexity of which should not be underestimated). How often does one of those engines fail?

Admittedly, a fusion rocket is on a whole different level to a jet engine, but considering that this thing is speeding through the solar system at 200 km/s, it should be a relatively mature technology.

it's called the EmDrive

AFAIK it still violates the conservation of momentum, and the results have not been replicated. I'd be weary of any "reactionless drives"- claims about them are a lot like claims about perpetual motion devices. AFAIK there was an inventor in SA who showcased his reactionless drive on TV a few years ago. I haven't heard of him since...

However, I have been looking into the [ame="http://en.wikipedia.org/wiki/Magnetic_sail"]Magnetic Sail[/ame] concept. It can work on a similar principle to a solar sail, except using a magnetic field to deflect charged particles in the solar wind. It can also be used to thrust directly against the magnetospheres of planets and the sun.

Perhaps it could be used to bring the spacecraft down to an acceptable velocity in the event of an engine failure, powered by the main reactor.

The self propelled sail sounds about as practical as a sailboat with a giant fan

It's essentially a photon drive (it's open, the photons leave the system), and it should work. The sail becomes superfluous. The problem is, however, that photon drives have abysmal performance (a single newton of thrust requires hundreds of megawatts).

Remote propulsion gets around the problem- lasers, masers or even particle beams are placed remotely, and the spacecraft only needs to carry the sail.

But for now I will be keeping with some sort of fusion drive.

 

[Izack]

It's essentially a photon drive (it's open, the photons leave the system), and it should work. The sail becomes superfluous. The problem is, however, that photon drives have abysmal performance (a single newton of thrust requires hundreds of megawatts).

Remote propulsion gets around the problem- lasers, masers or even particle beams are placed remotely, and the spacecraft only needs to carry the sail.

But for now I will be keeping with some sort of fusion drive.

Exactly my point. Just forego the sail and point the fan backwards. It's still bloody inefficient and will take you a year to get anywhere useful but it's better than deflecting your own air.

I agree that a magnetic sail could be useful, but since radiation pressure is still only modeled in the beta I'm not sure this is good for a stable release.