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Ramjets? Scramjets?


Guest Space Cowboy

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Best you'd likely get on Duna is Nuclear Thermal - there really shouldn't be anything that's going to have an energetic reaction in Duna's atmosphere.  You'd need life or an active geothermal system to maintain something like that in free-floating form.

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45 minutes ago, DStaal said:

Best you'd likely get on Duna is Nuclear Thermal - there really shouldn't be anything that's going to have an energetic reaction in Duna's atmosphere.  You'd need life or an active geothermal system to maintain something like that in free-floating form.

Or it could just be a SABRE-Type multimodal engine operating in closed-cycle mode with Fuel and Oxidizer, or a weirdly shaped conventional rocket.

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4 hours ago, Bej Kerman said:

How do you know it isn't a new type of jet?

Unless it’s a nuclear jet engine what is possible then it isn’t a jet. Jet engines combust fuel and oxygen to heat up and expand air. A nuclear jet engine uses the heat from a reactor to expand air.

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1 hour ago, SpaceFace545 said:
6 hours ago, Bej Kerman said:

How do you know it isn't a new type of jet?

Unless it’s a nuclear jet engine what is possible then it isn’t a jet. Jet engines combust fuel and oxygen to heat up and expand air. A nuclear jet engine uses the heat from a reactor to expand air.

Jets are a big part of atmospheric travel and they're fun to mess around with. Why would we only get one new type of jet?

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47 minutes ago, Bej Kerman said:

Jets are a big part of atmospheric travel and they're fun to mess around with. Why would we only get one new type of jet?

If you're talking about jets on Duna - what real-world jet would you think could work there?

There of course could be several models of nuclear thermal jets, but that's the only 'jet' technology I know of that would stand a chance to work in that atmosphere.  The next closest I can think of would be some form of electric turbofan.  (And you'd have to have some good EC storage/generation - if it's nuclear, just go with the nuclear thermal as it'll be simpler.)

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38 minutes ago, DStaal said:
1 hour ago, Bej Kerman said:

Jets are a big part of atmospheric travel and they're fun to mess around with. Why would we only get one new type of jet?

If you're talking about jets on Duna - what real-world jet would you think could work there?

What real-world rocket could get us to Alpha Centauri in a reasonable amount of time?

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2 hours ago, Bej Kerman said:

What real-world rocket could get us to Alpha Centauri in a reasonable amount of time?

Define 'reasonable', and how much money you're willing to spend.  The drives we've seen them show for interstellar drives all are based on known principles and technologies.  (Quibbles about metallic hydrogen aside - even there it's based on reasonable theories, even if there's major doubts about it working.)

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8 hours ago, Bej Kerman said:

What real-world rocket could get us to Alpha Centauri in a reasonable amount of time?

'Firefly' Starship Z-Pinch (D-D)
Raumfahrt+Astronomie-Blog von CENAP - Blog: Raumfahrt - Mit ...

100 years of flight to Alpha Centauri

Why this one? Yes, because 1. Helium-3 is not needed for its operation. All components on earth. 2. Z-pinch (D-D) looks simpler than detonating granules D-He3, as on Daedalus. According to modern research, it seems that Daedalus has huge problems with electrical equipment and propulsion. Not to mention the thousands of tons of Helium-3.
http://www.icarusinterstellar.org/e-beam-icf-for-daedalus-reconsidered/

Edited by OOM
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10 hours ago, DStaal said:
13 hours ago, Bej Kerman said:

What real-world rocket could get us to Alpha Centauri in a reasonable amount of time?

Define 'reasonable', and how much money you're willing to spend.  The drives we've seen them show for interstellar drives all are based on known principles and technologies.  (Quibbles about metallic hydrogen aside - even there it's based on reasonable theories, even if there's major doubts about it working.)

1. Depends

2. But interstellar drives don't exist yet.

5 hours ago, OOM said:

'Firefly' Starship Z-Pinch (D-D)
Raumfahrt+Astronomie-Blog von CENAP - Blog: Raumfahrt - Mit ...

100 years of flight to Alpha Centauri

Why this one? Yes, because 1. Helium-3 is not needed for its operation. All components on earth. 2. Z-pinch (D-D) looks simpler than detonating granules D-He3, as on Daedalus. According to modern research, it seems that Daedalus has huge problems with electrical equipment and propulsion. Not to mention the thousands of tons of Helium-3.
http://www.icarusinterstellar.org/e-beam-icf-for-daedalus-reconsidered/

But it doesn't exist yet.

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19 minutes ago, Bej Kerman said:

1. Depends

2. But interstellar drives don't exist yet.

But it doesn't exist yet.

Give me power over the world. And I will finance this, as well as make engineers work more actively.
After all, Skylon and Starship are the reusable rockets of the next decade to deliver parts for their construction. We can assume that everything is fine in this direction.

At the same time, I was still silent about the "sail." Which can reach Alpha in 30-40 years.

Edited by OOM
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7 minutes ago, OOM said:
25 minutes ago, Bej Kerman said:

1. Depends

2. But interstellar drives don't exist yet.

But it doesn't exist yet.

Give me power over the world. And I will finance this, as well as make engineers work more actively.
After all, Skylon and Starship are the reusable rockets of the next decade to deliver parts for their construction. We can assume that everything is fine in this direction.

At the same time, I was still silent about the "sail." Which can reach Alpha in 30-40 years.

But it doesn't exist yet and you don't have power over the world.

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6 hours ago, OOM said:

'Firefly' Starship Z-Pinch (D-D)
Raumfahrt+Astronomie-Blog von CENAP - Blog: Raumfahrt - Mit ...

100 years of flight to Alpha Centauri

Why this one? Yes, because 1. Helium-3 is not needed for its operation. All components on earth. 2. Z-pinch (D-D) looks simpler than detonating granules D-He3, as on Daedalus. According to modern research, it seems that Daedalus has huge problems with electrical equipment and propulsion. Not to mention the thousands of tons of Helium-3.
http://www.icarusinterstellar.org/e-beam-icf-for-daedalus-reconsidered/

It’s all fine but it’s not once you realize it’s 13 times longer than the Saturn v 

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1 hour ago, Bej Kerman said:

But it doesn't exist yet and you don't have power over the world.

well at least we know how to do it, and the concept is there. I guess

but I don't know a single concept that would allow you to jet around on mars. I still think that they could add ram/scramjets, since they would be useful for ssto's and flying around on oxygenated bodies like laythe and that one exoplanet with an abnormally large lake.

1 hour ago, SpaceFace545 said:

It’s all fine but it’s not once you realize it’s 13 times longer than the Saturn v 

well, bigger is better? :P

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2 hours ago, Bej Kerman said:

But it doesn't exist yet and you don't have power over the world.

 To go back and discuss the whole jets over Duna thing... if Duna is like its real world parallel, Mars, we can assume that the atmosphere is extremely thin, and primarily carbon dioxide... CO2 cannot be used as an oxidizing agent... since no gases are around to oxidize the propellant, one cannot reasonably use something that requires an oxidizer and propellant, but have no oxidizer present. As such, not even “theoretically” possible, as compared to some of the proposed propulsion technologies described

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44 minutes ago, Bej Kerman said:

How do you know?

I took high-school chemistry, which says to burn something you need three things: Heat, Fuel, and an Oxidizer.  Since *none* of those are available in Duna's atmosphere (or can reasonably expected to be), you'd have to bring all three.  Which then is a rocket, not a jet, except by the loosest definitions.

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3 hours ago, SpaceFace545 said:

It’s all fine but it’s not once you realize it’s 13 times longer than the Saturn v 

Let the construction time take decades - but you can still build

If you have SSTO of course.

 

But the question, as I understand it, was about how to fly on Dune / Mars. OK. And what is the problem of using a large wing and nuclear ramjet? In this case, you can disperse with a powerful electric motor or a small rocket stage.
I think that a modern, most compact and lightweight nuclear ramjet engine is a solution to how to fly in a CO2 atmosphere.

If without a nuclear engine, then I think that for light aircraft (400-500 kg) an ordinary, powerful electric motor is enough.

Or you can use a regular chemical rocket plane like J8M \ Me 163
Mitsubishi J8M Shusui

Edited by OOM
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