Questions tagged [advanced-propulsion]

Questions on spacecraft propulsion techniques that are either theoretical or not yet at a high technology readiness level.

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10 answers
3k views

Is there an elegant method to stop an asteroid's spin?

There have been proposals to mine asteroids, perhaps after “tugging” them to a more accessible location. As well, proposals have been made to move asteroids which threaten collision with earth. ...
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1 vote
0 answers
92 views

What are better ways to deliver heat directly to propellant in a Thermal Rocket design for use in launch than UV such as in the Nuclear Lightbulb?

Most advanced, high-power engine concepts that I came across aren’t suited for atmospheric launch, so I got curious about what kinds of engines could launch a very heavy craft from the surface of a ...
0 votes
0 answers
48 views

A hybrid micropropulsion system for CubeSats

I am curious about how much potential would a hybrid (electric & chemical) micropropulsion system have for CubeSats. The chosen propellant is water due to its non toxic nature, cheap cost and high ...
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1 vote
4 answers
148 views

Selecting an optimal Isp / what makes an Isp too high (mostly for high Isp)

When, and why, is it possible to have an Isp (usually of an ion or nuclear engine with Isp far beyond the limits of chemical fuel) that's too high? What makes the Isp too high, and (other things being ...
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3 votes
2 answers
295 views

Solid Core Antimatter Engines: Do they have a point?

On the graph discussed in this question, I was surprised to see "antimatter" listed as one of the engine types... with a disappointing performance equal to solid-core nuclear thermal rockets....
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5 votes
3 answers
359 views

Is the ejection of matter one way to get pushed the other way the only propulsion method we have?

I do mean propulsion (not gravity assist or the like). All the "rocket" engines I've seen (chemical, nuclear, ion, etc) seem to eject material one way to get the craft pushed the other way. ...
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3 votes
2 answers
257 views

How many existing satellites have a continuously varying orbit because of human design decisions?

In the space community, there is an assumption that changes to an Earth satellite's orbit are infrequent (other than those due to atmospheric drag). Are there any known satellites designed to ...
25 votes
3 answers
5k views

How realistic is the 1 kg/km² solar sail in "Death's End"?

(This question has been migrated from the SciFi StackExchange.) From Cixin Liu's 2010 sci-fi novel Death's End (pages 68–69): "A radiation sail can be made very thin and light. Based on the ...
3 votes
1 answer
170 views

Cooling the nozzle extension of a nuclear salt water rocket (NSWR)

The nuclear salt water rocket(NSWR) uses a plutonium salt (at least to my understanding) dissolved in water as its fuel. The mixture is kept stable by filling the fuel tank with boron carbide, which ...
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5 votes
2 answers
202 views

Using lasers to reach the Karman line

I've just seen this Anton Petrov video: New Type of Laser Levitation Could Help Us Explore the Mesosphere. It's about this new form of levitation that uses lasers to heat up the air underneath a craft,...
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5 votes
1 answer
128 views

What is the limit on ISP for cooled physical nozzles -- and how hard is it?

High performance chemical rockets, as well as hypothetical gas-core nuclear thermal rockets, can operate with chamber temperatures above the failure point of any available substance, because internal ...
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8 votes
3 answers
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Which theoretical propulsion system has the highest specific impulse?

I know that NERVA physically demonstrated 811 seconds, and the theoretical range for Orion was around 10,000. After stipulating that we can't really know for sure until it's built, given plausible ...
2 votes
1 answer
171 views

What are the practical limits of a rocket that receives propellant from the surface?

The Orion spacecraft was supposed to be propelled by igniting nuclear bombs behind it. Its proponents successfully demonstrated the concept using conventional explosives, on a small scale, for a few ...
4 votes
1 answer
598 views

How efficient and fast would seven Caplan thrusters be at pushing the Sun and would it be worth building more than one?

I was thinking about stellar engines. One type of stellar engine is the Caplan thruster, which concentrates the star's light onto the star's surface to create beams of solar wind, which are collected ...
7 votes
2 answers
1k views

Is the propulsion for the Scorpion nuclear-thermal-electric ship concept viable and credible?

Recently I've come across the proposal for the "Scorpion" spacecraft -- I originally ran across it on Project Rho (ctrl-F for it) but it looks like the article was published in the journal ...
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1 vote
1 answer
96 views

Is "nuclear electrothermal" a recognized term for a specific technology?

Is the term "nuclear electrothermal" recognized as referring to a specific type of propulsion technology (specifically, the nuclear thermal rocket with heat engine and arcjet afterburner)?
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2 votes
2 answers
239 views

Using heated water as propellant for a DT-He3 fusion thruster

Not sure if this would be best placed here or in World building SE, but I'll try here. Let's say I have a Dueterium-Helium 3 fusion pulse engine (similar to what is in the Expanse) that will use ...
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1 vote
0 answers
29 views

Injectors Diameter and Numbers

how would you determine the diameter and the number of injectors if unlike doublets elements are used? The Data given is: Isp =286 s Chamber pressure= 25 bars Propellant pair: Fuel= Hydrazine and ...
0 votes
1 answer
210 views

Continuous staging? [closed]

In industrial chemistry it's well known (Armagnac vs. Cognac) that continuous processes are more efficient than batch processes. In-game microtransactions have competed so favorably with just ...
5 votes
1 answer
856 views

Could the helical engine work?

A helical engine is originally described in this NASA Paper; see also the youtube explanation by Anton Petrov The problem may be with powering the device. The original paper uses ions in a toroid to ...
4 votes
1 answer
222 views

Which space drive concept would likely be most suitable for Interplanetary travel?

Of the several concepts of space propulsion drives listed for interplanetary launch, travel, and landings, which one should I research? Or is a good ole-fashioned ion drive adequate? Assume that all ...
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-3 votes
1 answer
150 views

A question about the feasibility of the Casimir propulsion system [closed]

There is a connection between vacuum energy density and the Casimir effect , see : https://arxiv.org/abs/quant-ph/0204125 Another reference can be found here: https://aapt.scitation.org/doi/10.1119/...
3 votes
2 answers
622 views

Does a feasible high thrust high specific impulse engine exist using current non space technology?

What I mean is an engine whose thrust is on the order of tens to hundreds of Newtons with an ISP "well" above that of chemical engines. I don't require this engine to be space ready - if it has to ...
12 votes
8 answers
4k views

Is it possible to get a spacecraft into earth orbit using Linear Eddy Current Braking on an orbital runway?

The "Space Runway" [I have slightly edited this to clarify some issues that have been raised] Luke Parrish mentioned an unusual and novel space launch method to me. The idea is to get a spacecraft ...
2 votes
2 answers
471 views

Would a nuclear turbojet with a chemical afterburner be a suitable intermediate between a pure nuclear turbojet and a nuclear thermal rocket?

NOTE: This is not the place to question the fundamental viability of nuclear propulsion in aircraft and spacecraft. For context, in a spaceplane, the higher speeds you can attain under air-breathing ...
0 votes
1 answer
288 views

Exit pressure value for vacuum nozzle [duplicate]

What value of exit pressure should I use in the design equations for a small liquid rocket engine nozzle for 200km-500km operating conditions? Since using zero as a value is not possible or else ...
1 vote
1 answer
308 views

Could a spacecraft be propelled by a 180 degree deflection of two charged particle beams?

I am wondering if the electrostatic deflection of two charged particle beams could create enough thrust, via the Lorentz Force, to propel a spacecraft. Please reference the picture below. This ...
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2 votes
1 answer
168 views

What could be the proprietary propellant blend that "Apollo Fusion" claims to have developed for it's hall effect thrusters?

According to the info posted on the Apollo fusion website http://apollofusion.com/ , they claim to use a propellant blend that offers " 2-3 X more impulse per mass and volume" in comparison towards ...
5 votes
1 answer
1k views

What would be the specific impulse of a continuous nuclear fusion drive?

Let's assume problems of running sustained nuclear fusion are overcome (be it by making the mechanism highly energy-positive, or just supplying all the energy deficit externally, like beamed power.) ...
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2 votes
5 answers
1k views

What is the most energy efficient & inexpensive propulsion system other than chemical fuel oxidizer that could be used in rockets?

I have read ionic/plasma propulsion system don't provide enough thrust to even lift themselves in Earth's atmosphere & photonic beamed propulsion is not in application yet so there any other ...
9 votes
3 answers
2k views

Teleporting an object into geosynchronous orbit

Assuming that a method was found to teleport objects, and at huge range, if an object was teleported from the surface to a location at the correct height (Wikipedia says about 42,164 km from the earth'...
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5 votes
2 answers
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How does the Sabre engine's pre-cooler achieve such high performance?

The BBC News article Rolls-Royce and Boeing invest in UK space engine about Reaction Engines Limited (REL) and its Sabre engine states REL is developing what it calls the Sabre engine. This power ...
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3 votes
0 answers
132 views

Are there any situations where hot rather than cold propellants might be advantageous?

Given that cryogenic fuel and oxidisers exist, I wonder if the reverse is workable. Are there fuels or oxidisers that have been considered for rockets that must be kept hot to be usable? By hot I ...
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4 votes
1 answer
817 views

Cost Estimation of Satellite propulsion systems

As part of my research project, i am evaluating various satellite propulsion systems. Are there any databases or forums where the ROM cost of a Satellite propulsion system is listed. A few new space ...
4 votes
5 answers
1k views

What will be the best way to convert nuclear fusion energy into thrust for a rocket?

Best means maximum thrust, safest, easy to maintain. And it's not opinion based because I'm looking for a way that's theoretically feasible and may be practical in a few years. However, if you have an ...
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0 votes
0 answers
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How can a nuclear spacecraft be in compliance with the Test Ban Treaty? [duplicate]

Specifically, a nuclear fusion rocket. And no pulse propulsion, because I know doing that will be very hard.
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5 votes
0 answers
123 views

What aerothermal effects present significant challenges in supersonic retropropulsion?

One of NASA's plans for future mars entry, descent and landing missions includes an ambitious deceleration process involving retropropulsion in a supersonic airflow environment. I know that previous ...
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4 votes
0 answers
112 views

Electromagnetic engines in heavy radiation regions

What sorts of peculiarities might affect an electromagnetic rocket (VASIMR or Magneto-Inertial Fusion) crossing Jupiter's radiation belts? Could all of that energy fry a magnetic thrust chamber and ...
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4 votes
3 answers
693 views

EmDrive compared to flashlight in space

From my (basic) understanding the most impressive thing about the EmDrive is it violates Newton's third law. No propellant is needed, nothing is jettisoned away, yet it, allegedly, accelerates in a ...
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2 votes
2 answers
208 views

Antimatter fuel compartment

Antimatter is theoretically an excellent fuel, providing large thrust/mass ratio and very efficient energy transfer. Therefore, we wouldn't need to use a lot of it to achieve similar thrusts that ...
6 votes
3 answers
523 views

What is our ability to capture or reflect photons with a wavelength of $2.5×10^{-12}$ meters?

Can we efficiently reflect or capture photons of that wavelength? More precisely, $ 2.426×10^{-12} $ meters, or $ 1.236 × 10^{20} Hz$ Preferably reflect, but capture followed by re-emission as ...
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5 votes
2 answers
2k views

Using Earth's magnetic field for an electric propulsion system

If you were to use a spacecraft built of copper in Earth's magnetic field, could you produce enough energy to propel yourself?
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7 votes
4 answers
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What kind of engine does this Isp = 1600 refer to? Is it cubesat-friendly?

These two good answers (one and two) to the question "Is there a maximum Isp for 'exothermic chemical reaction rockets?'" put the limits around 500-550 seconds for the limits of practical ...
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5 votes
2 answers
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Does the detection of gravitational waves prove we can travel faster than the speed of light?

From what I have read gravitational waves cannot travel faster than the speed of light. And since gravitational waves are part of the fabric of space, wouldn't that disprove the idea behind an ...
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6 votes
2 answers
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Could cosmic rays be produced by alien propulsion systems?

Could the cosmic radiation of heavy ions which hit us be the exhaust of advanced electric propulsion used by alien space travelers? While supernovae seem to cause part of them, much of it is far from ...
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5 votes
3 answers
287 views

What would be the challenges of a non-rotating tether orbiting the Moon?

There are examinations of lunar tethers going through the EML1 point, and rotating tethers in various orbits of the Moon. But I haven't seen an examination of a tether in orbit that doesn't rotate. ...
4 votes
0 answers
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What does a high Hall Effect Parameter mean in MPD thrusters?

MagnetoPlasmaDynamic Thrusters are plasma thrusters in which the acceleration of the fluid (plasma) is carried in a electromagnetic way. The electric field and the lorentz force are the primary causes ...
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2 votes
0 answers
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Switching off the magnetic coils in a Hall Effect Thruster

Talking about Hall Effect Thrusters (HET), we can say that the presence of a hollow cathode is relevant to reach a good operation of the thruster. We also can plot the potential-x (trajectory of ...
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4 votes
1 answer
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Electron buildup in Hall effect thrusters?

I was thinking about the Hall Effect Thrusters and how they are able to produce thrust. There's something that I don't understand: when the hollow cathodes emit electrons to neutralize the flow at the ...
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10 votes
3 answers
2k views

Is railgun propulsion being researched?

Specifically: not a "space gun" for launching payloads to space. This subject has been discussed a lot, and I know of the slew of problems and their partial solutions enough. I mean a device ...
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