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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27
votes
8answers
18k views

Why aren't linear aerospike engines in common use?

Linear aerospike engines are an old idea that seem so full of promise. Why are they not widely used today by the likes of Boeing, SpaceX, etc.?
11
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2answers
5k views

Solar sail thrust calculation

In Space Mission Engineering: The new SMAD, page 555, section 18.7.2, the following thrust formula is given for a solar sail: $$F=\frac{2RSA}{c}\sin^2\theta=9.113\times10^{-6}\frac{RA}{D^2}\sin^2\...
6
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4answers
2k views

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 ...
3
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5answers
409 views

Could fuel be “hosed” (pumped) from the ground to a launcher?

Most fuel on board a launcher is used during the first couple of minutes. Most of the propellant is needed to carry other propellant. For example, Saturn V (kerosene) and Delta IV (hydrogen) use about ...
10
votes
1answer
2k views

What is the performance of ion thrusters in actual deployed spacecraft?

Which spacecraft / satellites currently deployed in space (2015) use ion thruster propulsion and how do they compare? The wikipedia article have some comparative numbers, but some of the engines on ...
5
votes
1answer
405 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 ...
7
votes
3answers
444 views

Harpoon propulsion - what would be the problems?

Let's imagine we have finally developed buckytube rope. A couple hundred kilometers of rope, able to tug a 100-ton craft at 6g acceleration, in a package packable on said craft. A near-earth asteroid ...
32
votes
4answers
4k views

Is warp drive a legitimate avenue of scientific investigation?

I've been reading a number of online "pop-sci" articles on the subject of "warp drive" - derived from work done initially by Alcubierre. Some of the most recent articles say that there are ...
12
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2answers
2k views

How will the ion thruster powered Dawn spacecraft enter orbit around Ceres?

How is it possible for a ion thruster powered spacecraft like Dawn to decelerate to orbit Ceres? Does it have a secondary engine to accomplish this task?
10
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7answers
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 ...
5
votes
2answers
2k views

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 ...
8
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3answers
521 views

Can one put a large nickel-iron asteroid into an elliptical solar orbit that results in a soft(ish) earth landing?

My daughter and I are debating whether it is technically feasible to bring a nickel iron asteroid to the surface or the earth non-destructively. I felt it was impossible. Her thought was that with a ...
7
votes
3answers
1k 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 mounted ...
7
votes
3answers
2k views

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 ...
5
votes
2answers
975 views

Could a spaceship be “charged” with kinetic energy instead of having to be propulsed?

Could we use some kind of rotating sling or magnetic loop to accelerate a spaceship to (very) high speed and then release it and hurl it away? Today all spaceships are propelled by engines and some ...
17
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2answers
2k views

Why is the “impossible” space drive impossible?

So apparently NASA just built an impossible propulsion device: Sawyer's engine is extremely light and simple. It provides a thrust by "bouncing microwaves around in a closed container." The ...
16
votes
3answers
1k views

Pumped propellant propulsion - is it viable?

A recent article on Slashdot got me thinking. While the article is about using electric turbopumps for moving fuel from tanks to engines during launch phase and is just a small, incremental ...
5
votes
2answers
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?
5
votes
3answers
241 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
1answer
519 views

Books on rocket engine *dynamics*? [closed]

I'm a controls guy and I would like to "emulate" a given rocket engine's response behavior to different thrust signals inside a computer simulation. Thus I'm looking for a book that explains well the ...
4
votes
5answers
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 ...
8
votes
3answers
407 views

Burn 1st stage structural material as fuel?

Aluminum/Magnesium alloys can burn quite nicely. The stoichiometry is favoriable. Instead of $CO_2$ which is mostly oxidizer by mass, you might end up with $Al_2O_3$ and $MgO$ as exhaust. The ...
5
votes
2answers
2k views

Collecting antimatter from Van Allen radiation belts

I just read an article by John P. Millis, Ph.D which says that antimatter is created in the Van Allen radiation belts. I am writing a novel where a future starship with FTL capability, powered by a ...
5
votes
0answers
116 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 ...
5
votes
1answer
317 views

Could a sling launcher be used on Mars?

A sling launcher (discussed in this write-up by Landis) is a tower with a motor that spins a hub with two or more cables attached. Payload(s) are attached to the end of one or more cables and ...
3
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0answers
124 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 ...
2
votes
2answers
117 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 ...
1
vote
1answer
229 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 ...