Project Daedalus (1973-78)

[Spaceception]

3 hours ago, kerbiloid said:

When the fusion part will be "current", any other part will be "invented and pictured by Da Vinci".
So, a Steampunk ship with the engine from KSPI-E.

50 000 t of fuel, i.e., say 20 000 t of ³He.
Current technologists only dream about mining ³He on the Moon, 1 g of ³He / 100 t of regolith.
So, afaik, they were going to fuel this craft, mining He in the Jupiter upper atmosphere.
Don't know, what shocks me more: digging and frying 2 trln t of regolith or gathering several million tons of the Jup air.

No retro engines. It will fly forever until crashes into something. Good if into a star. Worse if into your planet.
I've checked the nukemap site to watch results of 500 t / 0.1 c collision with the Earth, but there's a 100 Mt limit.

P.S.
It's not a necro posting. Remember, it's about an interstellar flight. They last for eons.
It would be a necroposting >50 years later. Until then, it's just a lightspeed delay.

3

Yeah

It was a proof of concept, it was one of the ones more out there, but still. I think the revamped Icaris is more realistic, I haven't looked at it *Goes to atomic rockets*, but yeah, all that mining would've been insane, but the time it was built, we may already have ftl.

Oh, wow, so if a ship would to impact it, it would probably cause a small nuclear winter?

Hahahahahahaha

[Bill Phil]

1 hour ago, Spaceception said:

Yeah

It was a proof of concept, it was one of the ones more out there, but still. I think the revamped Icaris is more realistic, I haven't looked at it *Goes to atomic rockets*, but yeah, all that mining would've been insane, but the time it was built, we may already have ftl.

Oh, wow, so if a ship would to impact it, it would probably cause a small nuclear winter?

Hahahahahahaha

I don't think we'll get FTL any time soon... And even if we did, there's a lot to do in this solar system.

[Zeiss Ikon]

10 hours ago, Bill Phil said:

I don't think we'll get FTL any time soon... And even if we did, there's a lot to do in this solar system.

I'll make a prediction on that, similar to one Arthur C. Clarke made about life extension.

He said (quite a few years ago, now): "There are probably people alive today who will never die."

I'm going to approach it this way:  There are probably people alive today who will travel to another star -- and return alive to report to the same people who launched them.  To clarify, I think it's more likely we'll find a way to exploit the Alcubierre loophole (i.e. space warp) than that we'll ever launch generation ships or sleeper ships.

[cratercracker]

How was the project daedalus made:

-Do we need humongous balls or weird unaerodynamical fuselage?

-Yes.

[NSEP]

Cool. But that thing looks HUGE for something of 450 Tons. I think volume is a bigger problem than mass for getting it into space. 

[kerbiloid]

After they deliver into space a plant to mine 20000 t of ³He, their problem would bw to find the small 450 t probe between other metal junk.

[FreeThinker]

On 23-1-2016 at 4:18 AM, Spaceception said:

 that's the Daedalus, what do you guys think about it?

 

I like it to so I Kerbalized and integrated it into KSP Interstellar Interstellar

 

 

Edited August 8, 2017 by FreeThinker

[quasarrgames]

Raplace the fusion engine with an orion pulse drive, double or triple the transfer time, and it'd work just fine i think

 

[Elukka]

On 8/9/2017 at 9:56 PM, quasarrgames said:

Raplace the fusion engine with an orion pulse drive, double or triple the transfer time, and it'd work just fine i think

 

Orion designs had an isp of up to 4000 seconds. They thought it may be possible to raise that to 10 000 - 20 000 seconds through further development. The Daedalus proposal had an isp of 1 000 000 seconds. Orion is not remotely comparable.

Of course, we could probably actually build an Orion with current technology... but it's really not good enough for interstellar travel unless you're fine with it taking centuries. There's all sorts of numbers for much higher performance nuclear pulse propulsion floating about, but it's far more theoretical. It probably wouldn't look much like Orion as we know it and you might indeed consider Daedalus one of those advanced nuclear pulse propulsion concepts that have performance closer to the theoretical maximum.

Edited August 11, 2017 by Elukka

[wumpus]

2 hours ago, Elukka said:

Of course, we could probably actually build an Orion with current technology... but it's really not good enough for interstellar travel unless you're fine with it taking centuries.

The difference is that Orion could be built with 1960s tech, and flown to ~.1c with 1960s tech.  This should be fine for a long trip to Proxima Centauri.  Don't forget that much of the mass issues for Orion are for passenger comfort/survival.  Probes could be flown with vastly less mass (which would crank up the Isp).

There are more issues with traveling at highly relativistic speeds.  Star Trek mentions "navigation shields" that deal with all that hydrogen hitting them at speeds that turn them in to high speed radiation.  Nobody seems to have any idea how to build anything realistic that does that job.

My understanding was that the expected fallout from Orion was pretty low.  Of course, they didn't understand the magnetosphere and Van Allen belts at the time, so there was a pretty big error involved (nearly all the radiation produced would come back to Earth).  This can be avoided by launching in Antarctica.

[Rune]

31 minutes ago, Elukka said:

Orion designs had an isp of up to 4000 seconds. They thought it may be possible to raise that to 10 000 - 20 000 seconds through further development. The Daedalus proposal had an isp of 1 000 000 seconds. Orion is not remotely comparable.

Of course, we could probably actually build an Orion with current technology... but it's really not good enough for interstellar travel unless you're fine with it taking centuries. There's all sorts of numbers for much higher performance nuclear pulse propulsion floating about, but it's far more theoretical. It probably wouldn't look much like Orion as we know it and you might indeed consider Daedalus one of those advanced nuclear pulse propulsion concepts that have performance closer to the theoretical maximum.

The Isp of an Orion is a tricky thing to work out. For starters, the only designs seriously studied were the tinier ones possible, and thus atrociously inefficient. But in a few speculative papers (like this one), Dyson outlined the true limits of the tech when you have the right size. Of course, by "right size", he meant enough to use efficient thermonuclear (1MT/mT) pulse units, and a big spherical plate (and I mean big, like 20 kms wide, radiation cooled, and made of solid copper). In any case, cruise speeds of 1-10% of c are often considered plausible for nuclear pulse propulsion. That is more than comparable with theoretical fusion engines, which is not surprising, since those big "pulse units" are thermonuclear bombs deriving their energy mostly from fusion. And as plus, the payload can be city-sized.

 

Rune. Which has always made me wonder, why study fusion-powered starships and their heat issues, if we already know the shortcut to ignore waste heat and have stupendous efficiency with fusion-like Isp.

[DerekL1963]

59 minutes ago, wumpus said:

The difference is that Orion could be built with 1960s tech, and flown to ~.1c with 1960s tech. 

In theory.   In practice, what components have been tested have only been tested at the crudest, most primitive, proof-of-concept level.

[wumpus]

22 hours ago, DerekL1963 said:

In theory.   In practice, what components have been tested have only been tested at the crudest, most primitive, proof-of-concept level.

True, but the big thing is to make nuclear explosions when you want them (done) and never when you don't want them (presumably true.  Out of thousands of nuclear warheads built, none have gone off unexpectedly).  That leaves only:

The shock absorbers/pogo stick.  No idea if the ship (and crew) could survive even a single sticking shock absorber/pogo stick.  Presumably the big unknown of the vessel.  I don't remember a lot of testing of the shock absorber/pogo stick.

Will thousands of nuclear explosions weaken the pressure plate in ways we don't understand (being ablative, this is less an issue except for deep penetrating radiation and potential fatigue due to extreme shocks).

I assume that most of the rest of the R&D needed is in construction techniques for the thing.  For modern assembly, this might be more of an issue in that Orion designers presumably knew enough battleship construction engineers/workers familiar with making warship armor.  Since this is now a dead tech, we would have to learn these techniques (and blow up a few pressure plates).

[kerbiloid]

What especially impresses and amazes me much in Orion is that description of its inner machinery in Dyson's book.

A pure steampunk with water, oil, pipes and dials around. So wonderful...

Edited August 12, 2017 by kerbiloid

[magnemoe]

On 11.8.2017 at 4:12 PM, Rune said:

The Isp of an Orion is a tricky thing to work out. For starters, the only designs seriously studied were the tinier ones possible, and thus atrociously inefficient. But in a few speculative papers (like this one), Dyson outlined the true limits of the tech when you have the right size. Of course, by "right size", he meant enough to use efficient thermonuclear (1MT/mT) pulse units, and a big spherical plate (and I mean big, like 20 kms wide, radiation cooled, and made of solid copper). In any case, cruise speeds of 1-10% of c are often considered plausible for nuclear pulse propulsion. That is more than comparable with theoretical fusion engines, which is not surprising, since those big "pulse units" are thermonuclear bombs deriving their energy mostly from fusion. And as plus, the payload can be city-sized.

 

Rune. Which has always made me wonder, why study fusion-powered starships and their heat issues, if we already know the shortcut to ignore waste heat and have stupendous efficiency with fusion-like Isp.

An 20 km pusher plate would be somewhat expensive. it would also make the ship huge an massive.
An medusa like construction would be more practical at this sizes, as the parachute would be pretty thin,main issue would be how many blasts it could take. 

[magnemoe]

11 hours ago, wumpus said:

True, but the big thing is to make nuclear explosions when you want them (done) and never when you don't want them (presumably true.  Out of thousands of nuclear warheads built, none have gone off unexpectedly).  That leaves only:

The shock absorbers/pogo stick.  No idea if the ship (and crew) could survive even a single sticking shock absorber/pogo stick.  Presumably the big unknown of the vessel.  I don't remember a lot of testing of the shock absorber/pogo stick.

Will thousands of nuclear explosions weaken the pressure plate in ways we don't understand (being ablative, this is less an issue except for deep penetrating radiation and potential fatigue due to extreme shocks).

I assume that most of the rest of the R&D needed is in construction techniques for the thing.  For modern assembly, this might be more of an issue in that Orion designers presumably knew enough battleship construction engineers/workers familiar with making warship armor.  Since this is now a dead tech, we would have to learn these techniques (and blow up a few pressure plates).

Yes, if a bomb don't go off it would simply fall behind, one issue would be an fizzle, as its an shaped charge you might get an uneven blast given uneven pressure on plate who could damage the shock absorber. 

The shock absobers would be easy to calculate requirements for. This would be the first obvious question and must have been done for the smaller designs who got detail plans. 
Plates would be easier to build today because of better materials, 
And yes you would have to test it well. 

[wumpus]

15 hours ago, magnemoe said:

An 20 km pusher plate would be somewhat expensive. it would also make the ship huge an massive.
An medusa like construction would be more practical at this sizes, as the parachute would be pretty thin,main issue would be how many blasts it could take. 

I'd assume that you would hammer out an asteroid for the pusher plate (this might kill your Isp).  No idea on how you build the pogo-stick and shock absorbers for it (especially considering that a single failure/jam/sticking would likely kill everyone on board).  Of course if you build it on Earth, getting such into space can be pretty cheap (but still, you don't have reasonably pure metals lying around by the km**2 like you can find in the asteroid belt).

Don't forget that if you build it on Earth, it at least has to be assembled at Antartica (and probably launch with neutron bombs or ideally fuel-air explosives).

[Rune]

On 13/8/2017 at 2:48 AM, magnemoe said:

An 20 km pusher plate would be somewhat expensive. it would also make the ship huge an massive.
An medusa like construction would be more practical at this sizes, as the parachute would be pretty thin,main issue would be how many blasts it could take. 

Depends entirely on your payload size. If you are pushing an O'Neill style habitat, 20kms wide is just about good enough to cover both cylinders with some margin for the low-grav farms around them. But yeah, structurally speaking it would probably be more efficient to use a Medusa-like tractor system, especially at those sizes. Of course the sail (much better to think of it that way) would be just as thick as it is required, plus margin (and could be a good radiation/debris shield during flight).

On 13/8/2017 at 6:46 PM, wumpus said:

I'd assume that you would hammer out an asteroid for the pusher plate (this might kill your Isp).  No idea on how you build the pogo-stick and shock absorbers for it (especially considering that a single failure/jam/sticking would likely kill everyone on board).  Of course if you build it on Earth, getting such into space can be pretty cheap (but still, you don't have reasonably pure metals lying around by the km**2 like you can find in the asteroid belt).

Don't forget that if you build it on Earth, it at least has to be assembled at Antartica (and probably launch with neutron bombs or ideally fuel-air explosives).

Daedalus assumes colonies mining fusion fuel by the million metric tons, from the atmosphere of Jupiter. I think I can assume free solar orbit construction form asteroid material, conveniently manufactured into aerospace-grade parts, to build such interstellar behemoths.

 

Rune. Fission fuel would be probably cheaper to manufacture on Earth, but a starship that has to brake at the other end should be able to manufacture its own bombs, 'cause half-life.

Edited August 16, 2017 by Rune