The Nuclear Rocket that Could Reach 20% the Speed of Light

[caballerodiez]

In 2009, the same society together with the Tau Zero Foundation announced Project Icarus, a similar spacecraft that could achieve 15% the speed of light.

That year, a physicist called Friedwardt Winterberg announced a fusion spacecraft that could be used as a capacitor to produce proton beams that would ignite deuterium micro-bombs. However, this technology would have to be constructed in space and the cost would be too expensive. For this reason, Winterberg proposes that the nuclear fuel could be ignited by Marx generators.

In this line, Chief Scientist of Icarus Interstellar Adam Crowl has suggested that a two stage-configuration of the Winterberg rocket could achieve 20% the speed of light. The starship would weigh 120,000 tons, and the amount of deuterium needed would be 12,000,000 tons. It would only take around 20 years to reach the closest potentially habitable exoplanet, Proxima b.

Source: https://www.youtube.com/watch?v=DT5zkUq3VDY

Considering that the first nuclear fusion rocket could be ready for launch by 2028, how plausible do you think this nuclear rocket design is?

 

[Spacescifi]

 

I dunno... why not explore our own solar system before sending a spacecraft on a one-way trip to no where?

There are death worlds at Alpha Centauri, and we have that here too, so may as well use that technology in our system where we get more return on our investment.

Edited October 26, 2019 by Spacescifi

[kerbiloid]

  Reveal hidden contents

I can understand that they made the last ship out of IXS Enterprise parts.
But did they put on it a twin Alcubierre?..

 

[IncongruousGoat]

  On 10/26/2019 at 7:20 PM, caballerodiez said:

The starship would weigh 120,000 tons, and the amount of deuterium needed would be 12,000,000 tons.

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This alone is a near-insurmountable problem. A 120,000-ton vehicle is technically feasible (there are container ships that are several times as massive), but 12 million tons of deuterium is not happening for any reasonable sum of money. You'd be looking (based on some cursory research) at hundreds of billions to trillions of dollars per flight for fuel costs.

If we're talking ways to get something to Proxima B within our lifetime, solar sails are the way to go. That something being a probe, of course. Humans to another star ain't happening with any technology we know how to build.

But, as @Spacescifi said, why would you want to make that trip? We've got a perfectly good unsettled, largely unexplored solar system right here.

[Spacescifi]

  On 10/27/2019 at 7:49 PM, IncongruousGoat said:

 

But, as @Spacescifi said, why would you want to make that trip? We've got a perfectly good unsettled, largely unexplored solar system right here.

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In the hope that there is life out there since the planet is in the habital zone.

Popular accepted ideas and theories can be misleading, as such have lead several to think that life can and will arise randomly around the universe.

Thus whenever they see a star or system remotely like ours they believe life could or at least should be there.

Assuming life happens randomly by chance like they already believe. If that is not the case though, then the answer is simple. It does'nt. So neither should we expect it to be on a planet just because it is in the habital zone.

Edited October 27, 2019 by Spacescifi

[Gargamel]

  On 10/27/2019 at 7:49 PM, IncongruousGoat said:

why would you want to make that trip?

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Because we can. 

Moved to S&S

[kerbiloid]

  Quote

12 000 000 t of deuterium

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How many is it in starships?

That's a next bus stop for Space-X roadmap.

[Guest]

  On 10/27/2019 at 7:49 PM, IncongruousGoat said:

This alone is a near-insurmountable problem. A 120,000-ton vehicle is technically feasible (there are container ships that are several times as massive), but 12 million tons of deuterium is not happening for any reasonable sum of money. You'd be looking (based on some cursory research) at hundreds of billions to trillions of dollars per flight for fuel costs.

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It probably can be calculated. The world hydrogen production is 70 million tons. 0.03% of this is deuterium, by mass. So, you have to take all hydrogen produced all over the world, extract all the deuterium, and store it. For six years straight. That's 12 million tons. Of course, that is based on first numbers I found on the internet, but for the first order approximation, it's fine.

  On 10/28/2019 at 9:32 AM, kerbiloid said:

How many is it in starships?

That's a next bus stop for Space-X roadmap.

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More than you'd expect. Starship will not "gross out" when loaded to capacity with deuterium, which is denser than straight hydrogen, but not by that much. We don't know how much volume Starship would have available for D2 tankage, so we can't really answer that question, but it's definitely not a good vehicle for carrying deuterium.

[kerbiloid]

  On 10/28/2019 at 8:36 PM, Dragon01 said:

We don't know how much volume Starship would have available for D2 tankage

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I would say that the volume limits, rather than mass, is what we can know more or less definitely from the given size.

  On 10/28/2019 at 8:36 PM, Dragon01 said:

it's definitely not a good vehicle for carrying deuterium.

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But it's the best we can see on the table to deliver 12 000 000 t of liquid deuterium to LEO in the foreseeable. future.
Of course, we could measure in ur-900s (750 t of payload, but not reusable) or orions, but starships are currently a more relevant example.

Also Space-X can just put moar engines, like usually.

***

Suggestion: instead of space elevator we may want to have a refuel tower with deuterium pipe.
Also useful for hydrolox.

  On 10/28/2019 at 4:34 AM, Gargamel said:

Because we can

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We can? Okay...

Edited October 29, 2019 by kerbiloid

[Guest]

  On 10/29/2019 at 4:32 AM, kerbiloid said:

I would say that the volume limits, rather than mass, is what we can know more or less definitely from the given size.

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We know the size of outer skin, not tankage. This thing is going to need thermal protection, avionics and all that stuff (for D2, also insulation), so the tank inside will have to be much smaller, even for the tanker version. Dry and propellant masses have been given for both Starship and BFR (though there are a few variants), so payload mass is easily calculated.

[kerbiloid]

  Reveal hidden contents

  On 10/29/2019 at 10:28 AM, Dragon01 said:

We know the size of outer skin, not tankage. This thing is going to need thermal protection, avionics and all that stuff (for D2, also insulation), so the tank inside will have to be much smaller, even for the tanker version.

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indeed, this can be a battleship-thick armor made of tungsten and lithium rather than steel or aluminium with minimal insulation.

Though I would suggest to return to the thread topic.

[Guest]

Actually, a monolithic tungsten heatshield is a very good idea, and it was supposed to be used on Space Shuttle. Here's a hint, steel and aluminium don't handle orbital reentry all that well, and with Shuttle tiles you can forget about anything approaching rapid reuse. 

Let's not forget that if you put "minimal insulation" on a tank of LD2, then you might as well be carrying it in a sieve. You don't need a full-on ZBO tank for LEO delivery, but you do need insulation at least on the level of Centaur, and this foam has a significant volume.

[mikegarrison]

  On 10/29/2019 at 11:08 AM, Dragon01 said:

with Shuttle tiles you can forget about anything approaching rapid reuse.

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Still the most rapidly reused orbital spacecraft of all time. Just saying.

[Guest]

Didn't X-37 beat it at one point? It also uses tiles, but not so darn many of them. At any rate, it was not rapid by any reasonable definition. Its achievement was that it was reusable at all. Compared to the original expectations, the actual turnaround rate was abysmal, in large part due to the heatshield being such a pain.

[mikegarrison]

  On 10/30/2019 at 7:29 PM, Dragon01 said:

Didn't X-37 beat it at one point? It also uses tiles, but not so darn many of them. At any rate, it was not rapid by any reasonable definition. Its achievement was that it was reusable at all. Compared to the original expectations, the actual turnaround rate was abysmal, in large part due to the heatshield being such a pain.

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Not X-37, I don't think. There are two X-37B spacecraft, and they have been used on alternating missions.

There are really only a few heat shield options for a reuseable re-entry vehicle.

1) tiles like the Space Shuttle, X-37B, Dreamchaser, Space-X Starship

2) ablators that are one-time-use heatshields that get replaced after every landing

3) inflatable (almost certainly one-time use)

4) something actively cooled

[wumpus]

  On 10/30/2019 at 10:15 PM, mikegarrison said:

Not X-37, I don't think. There are two X-37B spacecraft, and they have been used on alternating missions.

There are really only a few heat shield options for a reuseable re-entry vehicle.

1) tiles like the Space Shuttle, X-37B, Dreamchaser, Space-X Starship

2) ablators that are one-time-use heatshields that get replaced after every landing

3) inflatable (almost certainly one-time use)

4) something actively cooled

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Is Space-x still planning on open-loop "sweating" cooling in Starship?  Pump fuel/oxidizer (whichever has the best cooling capacity) out through tiny holes and use that for active/ablative cooling?  And I'm not sure what else you could mean by "active cooling": it isn't like there is an available source of cold atmosphere to flow through a radiator.  You could pump heat to superheat a radiator (which could black-body radiate if you had to), and maybe by the time flowed around the spacecraft it will have re-expanded and cooled off (so it *could* flow through a radiator), but these all seem unlikely.

[Guest]

5) A monolithic (or segmented, but only for manufacturing reasons) tungsten plate. 

Space Shuttle, at one point, was supposed to use that. Yes, it's expensive, but does not require active cooling and does not noticeably ablate during a normal reentry (melting point at nearly 3700K will do that). It's also mighty though, which would comes in rather handy if struck, say, by a high-speed piece of foam.

Why has it never been flown? Price. A tungsten heatshield is overkill for a single-use capsule, or one with very limited reuses, like all those built so far (PICA-X, used on all Dragons, does ablate). Space Shuttle didn't get it, because it was over budget already, and NASA thought tiles will be cheaper. And they were... until you factored in the cost of checking every single one, by hand, before every flight. X-37B appears to build on Shuttle technology. We don't know what Starship will use, BTW. Artists draw it with tiles because they only have the Shuttle to go on. If they use the same kind of heatshield as the Shuttle, they'll have the same problems it had (except foam strikes, fortunately).

Active cooling is pretty much something like "sweating" system, otherwise you need a heatsink to shunt the heat into. TBH, I find the idea, in the proposed form, far-fetched and likely impractical. Not to mention it will likely not suffice without some kind of heat resistant backing material.

Edited October 30, 2019 by Guest

[mikegarrison]

  On 10/30/2019 at 11:08 PM, Dragon01 said:

We don't know what Starship will use, BTW. Artists draw it with tiles because they only have the Shuttle to go on.

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Uh, no.

While it's true that SpaceX doesn't seem to have committed to a final design (probably intentionally), SpaceX themselves have talked about a tile-based heat shield. AFAIK, it's their current default. Anyway, it's a lot more than just "artists draw it with tiles because they only have the Shuttle to go on".

[kerbiloid]

  On 10/30/2019 at 10:15 PM, mikegarrison said:

There are really only a few heat shield options for a reuseable re-entry vehicle.

1) tiles like the Space Shuttle, X-37B, Dreamchaser, Space-X Starship

2) ablators that are one-time-use heatshields that get replaced after every landing

3) inflatable (almost certainly one-time use)

4) something actively cooled

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DynaSoar and Spiral were designed with niobium heatshield. Spacedesigners of that time loved niobium, even when some of them called it columbium.
(Just discovered in wiki that it's renamed.)

VA of TKS used a reusable ablator-like heatshield made of organosilicon matrix reimpregnated up to 10 times with resin filler.
On heating the resin evaporated and formed a gas cloud in the matrix working as insulator. It ablated, but the principle was not in ablation, it was a side-effect.
The matrix itself "haven't lost a millimeter, just looked like scratched with sandpaper".
(Can't find the photo at the moment, but it indeed looks like described: not deformed but worn).
The heatshield itself is also described as pretty lightweight.

Edited October 31, 2019 by kerbiloid

[DDE]

  On 10/30/2019 at 11:08 PM, Dragon01 said:

Why has it never been flown? Price.

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  On 10/31/2019 at 7:01 AM, kerbiloid said:

DynaSoar and Spiral were designed with niobium heatshield. Spacedesigners of that time loved niobium, even when some of them called it columbium.
(Just discovered in wiki that it's renamed.)

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The minor problem at the time was that the DynaSoar required more than the annual global output of niobium.

Earlier designs looked at thorium oxide instead.

[farmerben]

Current levels of production for niobium and other materials may not be good bases for estimating what is affordable.  

We could mine more and probably increase those levels x10 in ten years with a small price increase.  Brazil has basically done so for niobium recently.  Most rare earth mines in the United States are shut down because they are not permitted to do anything with thorium rich tailings.  

Anybody anywhere can make deuterium.  So if you're willing to invest and wait for it, you can have many times the current world production of deuterium.

[kerbiloid]

But anyway the world production of niobium is tens thousands of tonnes per year, so it's enough for a small spaceplane.

[Guest]

Yes, but it skyrocketed in recent years. It's actually a few million tons by now. DynaSoar was a late 50s/early 60s project, when niobium production was much lower, and it didn't have as many uses as it does today. 

[Terwin]

  On 11/11/2019 at 12:13 AM, farmerben said:

We could mine more and probably increase those levels x10 in ten years with a small price increase.  Brazil has basically done so for niobium recently.  Most rare earth mines in the United States are shut down because they are not permitted to do anything with thorium rich tailings.  

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Not so much 'not permitted' as 'required to' the only problem is, the 'required to' is 'dispose of it as enriched nuclear materials' (because they removed several percent of the total volume when extracting the 'rare earths' they were mining, leaving the thorium fraction slightly higher than it was originally).

If they could find a buyer for the Thorium, or even just throw the tailings back into the original hole, they could still make money(at least when a certain country is not selling below cost to try and drive others out of the rare earths market).

[magnemoe]

  On 10/27/2019 at 7:49 PM, IncongruousGoat said:

This alone is a near-insurmountable problem. A 120,000-ton vehicle is technically feasible (there are container ships that are several times as massive), but 12 million tons of deuterium is not happening for any reasonable sum of money. You'd be looking (based on some cursory research) at hundreds of billions to trillions of dollars per flight for fuel costs.

If we're talking ways to get something to Proxima B within our lifetime, solar sails are the way to go. That something being a probe, of course. Humans to another star ain't happening with any technology we know how to build.

But, as @Spacescifi said, why would you want to make that trip? We've got a perfectly good unsettled, largely unexplored solar system right here.

Expand  

And even solar sails will be very expensive as you need to laser pump them. 
Now research into fusion engines itself is very useful for our own solar system. 
An extensive manned mission to Saturn sounds nice.

One thing I have tough about a bit, the starshot project planned to bounce an laser between the probe and the laser system lots of time with mirrors in both ends.
Yes their project is pretty idiotic ambitious, 20.000 g acceleration, yes it works for artillery shells, but they are thick steel casings inside an barrel, not an thin mirror pushed by an reflecting laser, if any part is 1% off it faces 100 g force on that part. 

On the other hand if you have an more traditional some hundreds kg probe  accelerating at say 0.1 g things get way easier. Now you have plenty of time to correct for errors. 
Yes you need to trust for weeks so cooling requirements for lasers goes up but that is just adding more radiators.