Questions tagged [design-alternative]

Questions about alternative designs the asker has thought of, such as "why was X built this way and not this way"

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How should mass specific impulse calculated for relativistic exhaust?

This answer says: Optimising for Isp only is problematic, as it's simply: $$I_{sp} = \frac{v_e}{g}$$ Which is the same as optimising for exhaust velocity. With no constraints on thrust, particle ...
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11 votes
3 answers
5k views

What are the biggest challenges for high altitude rail-gun launch systems?

Use a maglev railgun for initial acceleration - in a new, hyperbolic tunnel facing eastward - this exits from the burrowed -undergrade- track to Equadors' Mt. Chimborazo peak - (a mountaintop both 6 ...
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2 votes
1 answer
330 views

Could a CubeSat be propelled by this low-tech electromagnetic propulsion system?

I have come up with a conceptual idea for a low-tech electromagnetic propulsion system for a CubeSat, and I would like to know if it would create (on a theoretical basis) a net force strong enough to ...
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34 votes
6 answers
11k views

Why aren't air breathing engines used as small first stages?

I am wondering why we don't use jet engines as first stages. Most small rockets, like the Electron, can lift off with a small thrust. In the Electron's case, 192 kN. Why can't we replace the 9 ...
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18 votes
3 answers
3k views

Could a spacecraft be made out of wood?

Could a spacecraft use organic materials, like wood or bone or shell or other tissues, as an interface to the vacuum and radiation of space? Would wood outgas and crack up in space? I wonder if life ...
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15 votes
8 answers
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Would a duct tape spacesuit be practical?

Spoilers ahead for season 2 of For All Mankind. Essentially duct tape wrapped around the body, over clothing which looks like standard NASA jumpsuits for pressurized environments onboard spacecraft. ...
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5 votes
3 answers
557 views

If specific impulse is directly related to exhaust velocity, would a ion post-accelerator improve the Isp of a propulsion system?

I understand that ion- and hall thrusters resemble a particle accelerator, and that led me to wonder if a post-accelerator (particle accelerator) used to boost the velocity of the ions would improve ...
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1 vote
3 answers
566 views

Could a horseshoe magnet help a satellite stay in orbit?

If a horseshoe magnet was attached to a satellite orbiting the Earth, would the interaction of the Earth's magnetic field and the horseshoe magnet's magnetic field result in the magnet being propelled ...
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8 votes
1 answer
264 views

Is methylsilane CH6Si ever considered as fuel in rocketary?

Methylsilane CH6Si seems to have some useful properties for rocket fuel: High hydrogen content, 6 atoms per molecule, 13% of overall mass, High combustion energy, -2612KJ/mol or 56.8 MJ/kg (better ...
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5 votes
2 answers
315 views

Was there any launch vehicle possible that could have been used for a heavier New Horizons with enough fuel to enter Pluto orbit? (adding ~10 years)

Answers to the Astronomy SE question Can New Horizons probe turn back and start orbiting Pluto are of course no, it would have to have been a different mission with a lot more fuel and a bigger launch ...
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5 votes
3 answers
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Two 1000 kg gold spheres orbit their CM in near-contact, great way to measure G or limited by spaceflight issues?

The hypothetical, non-existent crowdfunding site go-launch-me is so confident, they are offering a two-for-one special. For a limited time, if your project is funded they will foot the bill for a 2nd ...
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4 votes
7 answers
4k views

Would it have been cheaper and/or faster to put a James Webb-like Space Telescope on a balloon instead of a rocket?

I've just noticed the following items: CNET: NASA to send stadium-size balloon skyward to study the cosmos JPL/NASA News: NASA Mission Will Study the Cosmos With a Stratospheric Balloon Even in 2020 ...
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3 votes
1 answer
207 views

Would a small electron microscope in a cubesat work well in space at 400 km?

There is now an electron microscope in space! Suppose that once I win a lottery I can build a small, modest SEM column and put it in a 6U cubesat that opens one side to allow the electron optics to ...
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1 vote
0 answers
126 views

Technological challenges to sending a high altitude balloon to space and orbit from 50 km?

Below At what altitude would I have to go in a lighter than air balloon to be above all wind and just have the earth rotate underneath me? there is a comment: If you want to be above all winds, you ...
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18 votes
6 answers
4k views

Would a higher air pressure on the ISS or elsewhere make it easier to "swim" in microgravity?

What if the atmospheric pressure onboard the ISS was 5 atm, 5 times the pressure on Earth and currently on the ISS, while maintaining the breathable oxygen level, e.g. if the additional atmosphere ...
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13 votes
3 answers
4k views

Rocket flywheel instead of battery/generator (crazy idea)?

The Electron rocket is launched using a battery instead of generator... I saw some video about research into using flywheels for energy grid buffer storage, I think that they could reach higher ...
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6 votes
2 answers
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Can a VASIMR Plasma engine be used to launch a rocket?

When I was in primary school, I spent countless hours designing spaceships that probably wouldn’t work. It’s only now that I’ve stumbled across some of the old drawings and actually thought if it ...
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2 votes
1 answer
171 views

Why did Deep Space 1 use solar concentrators?

@Hobbes' answer mentions that Deep Space 1 used special refractive solar concentrators attached to photovoltaic cells. According to SCARLET: The innovative array uses 720 lenses to focus sunlight ...
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0 votes
3 answers
202 views

Prior to putting spacecraft on a trajectory going a significant fraction of the speed of light, would some things need to be tested on Earth?

Except for particle accelerators, I don't think we have made any macro object go anywhere near the speeds planned for spacecraft like the one planned in Project Orion. But would there be something ...
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23 votes
3 answers
5k views

Why isn't SpaceX constructing the Super Heavy launch mount on top of the water?

With SpaceX creating their launch facility in Boca Chica Texas, right next to the water, why would they bother building a huge launch pad to withstand the blast, as opposed to building it on top of ...
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7 votes
3 answers
392 views

Fast spinning solar cells to clear Martian dust possible?

I've seen a fast spinning glass wheel used in front of a camera to clear away water, dust or ice. Could Solar panels be made circular and spin to clear dust off of them in the same way may? As ...
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6 votes
1 answer
474 views

Is there anything fundamentally wrong with 'autogenous expander cycle`?

This question is a spinoff from here. To set the context, here is my understanding of the expander cycle: Closed expander cycle is very efficient, perhaps more efficient than staged combustion cycle....
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5 votes
1 answer
433 views

Could a fairing vacuum protect the payload from acoustic loads?

This is a weirder question, but here it goes: During launch, a payload (let's say a satellite) undergoes intense shaking and acoustic loads. This is known from the launcher parameters and the ...
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5 votes
7 answers
1k views

Vacuum launch, essentially free after system built

Outside Earths atmosphere is the vacuum of space and its immense power. If a cylindrical tube of sufficient strength and size were built tall enough to reach the edge of atmosphere would it not be ...
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4 votes
2 answers
119 views

Ramscoop for a space station or lunar base?

From what I've read, the Bussard ramscoop has problems which make it impractical as a means of propulsion. However, would it be possible to use it for a different purpose? Could a space station or ...
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4 votes
2 answers
598 views

What is the Isp of gunpowder likely to be? Could this table be right? Can it even be determined?

There are some unsourced refutations of the value for the Isp of gunpowder in the table shown below can be found under What kind of engine does this Isp = 1600 refer to? Is it cubesat-friendly? Alas ...
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3 votes
0 answers
253 views

Could a steam Engine outperform other electric producing devices in space? [closed]

What would be the Specific Impulse of a steam-based propulsion system like this model in space? Are there any types of engine that works this way? Could 2 tanks be designed to rotate slowly in space ...
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1 vote
1 answer
137 views

Would an incandescent light bulb be more efficient than a laser for photon propulsion?

In an incandescent light bulb pretty much almost all of the input power is radiated as photons. While perhaps 10% of the power is useful for human vision and the rest are longer wavelengths, it's all ...
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1 vote
1 answer
410 views

Liquid shield for spacecraft? [closed]

Could an alloy of hot or cold liquid metal be made magnetic by adding electricity to the molten ball to give it magnetic properties to wirelessly attach it to a space craft to use as a shield shown in ...
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-2 votes
1 answer
257 views

Could a rocket launch off water horizontally in stages us using water and air for lift to save fuel? [duplicate]

A term I have heard is the "water was like class". Meaning that the water had 0 waves. Could a rocket be modified to take off a horizontal surface starting slowly increasing throttle on each stage? ...
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28 votes
8 answers
7k views

Would a grinding machine be a simple and workable propulsion system for an interplanetary spacecraft?

I am wondering if any space agency has ever considered using a grinding machine as a propulsion system for an interplanetary spacecraft. This system would not be used to lift the spacecraft off of a ...
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10 votes
1 answer
681 views

Does a high staging number have diminishing returns? Is there a way to address that mathematically?

I was reading this question: Help me understand what Farside, a ten "stage" rockoon looked like? How was it configured? Comments link to Highest stage counts in actual launchers? but here ...
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9 votes
6 answers
3k views

Using water as a high density storable hydro-lox propellant

Hydro/lox is an excellent fuel choice and has been used in many engine/rockets with high ISP requirements, however, the two biggest drawbacks of the propellant are its density and boil-off. Could this ...
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2 votes
2 answers
345 views

Could electricity be generated from a Martian dust storm?

This helicopter is producing static electricity from the blades moving through the dusty air. Along with the electricity provided by wind generators could additional power be created this way from ...
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26 votes
3 answers
6k views

Are there any greater risks of traveling significantly faster to another planet?

Earlier I had thought that space ships can strike against space rocks while traveling to another planet. But I've read that space is vastly empty, it's highly unlikely that something will come in the ...
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18 votes
5 answers
11k views

Why doesn’t NASA build its rockets using graphene?

Graphene would be a great material to build a rocket out of. Graphene is extremely thin. One single atom thin layer of graphene can withstand 15 000 000 pascal . A square meter of this material only ...
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14 votes
3 answers
1k views

A way to overcome fuel limits on JWST and its operational lifetime; "clip-on" propulsion systems in development that might work in the future?

I was wondering: Although it has been widely publicised that the JWST has a lifetime limit. Is it not it possible given current technology regarding drones and the JWST itself as proof of concept to ...
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13 votes
7 answers
9k views

Could a space colony 1g from the sun work?

Let me break down my thoughts and I have no science background so let me know if this could even be possible. Have the colony on an object like a big asteroid or a similar man made construct. Have ...
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5 votes
1 answer
218 views

What is the smallest object our current technology is capable of launching into space?

Well, I'm quite ignorant about space exploration in general, but I hope I don't make too many misconceptions. So, from what I could find on the internet, there is a certain type of spacecraft ...
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5 votes
1 answer
413 views

How much does launch costs have to come down to make chemical fuel deep space probes feasible?

Considering that NASA have been running short of plutonium for their RTGs, it makes sense to consider alternatives. For the inner solar system up to Jupiter, solar cells have been demonstrated on ...
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2 votes
1 answer
242 views

Why rockets are not tossed up before launch [duplicate]

Ok, I understand the nature of my question but anyway why the rockets are not tossed up before launch. It could introduce a huge handicap for a rocket in terms of reduced distance it has to travel, ...
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1 vote
0 answers
204 views

Orbit to Orbit Transport Stage

Would it be faster or cheaper to have a lander, SSTO, and/or SpaceX Mars rocket to rendezvous connect with a more efficient engine or "transport stage" or another lander, SSTO? When the spacecraft ...
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0 votes
1 answer
198 views

Would the Poynting–Robertson effect ever be faster than a solar sail from a 1 AU orbit to the Sun?

In this answer to Do you need 0 km/s velocity to crash into the sun? I mention solar sails for retrograde thrust and the Poynting–Robertson as two ways an object could ever-so-slowly spiral into the ...
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12 votes
1 answer
3k views

Why is an inflatable balloon inside a fuel tank not used to prevent fuel from "sloshing around"?

After seeing all the Starship failures, having something with a membrane keep things in place seems like an obvious solution. Has it been considered or tested - or do we simply lack a material that is ...
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10 votes
1 answer
770 views

What's the final word; does the EmDrive drive work or not?

I'd like to know the final verdict on the EmDrive (or EM Drive); does it work or not? Some say yes, others say no, some say the measured effect was not propulsion, but just the energy radiated by the ...
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9 votes
0 answers
176 views

Has there ever been a deliberate "Find A Satellite" challenge? Actually, could there be?

Companies often offer rewards for finding security issues in their products or their own IT systems, and hackathons have a long history. I'm just wondering if there has ever been a deliberate ...
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8 votes
2 answers
1k views

Why can’t cryogenic propellants be storable, at least on the ground, via refrigeration?

Cryogenic fuels (liquid hydrogen, liquid methane)1 and oxidisers (liquid oxygen)2 are the rocket propellants of choice where raw performance is the overriding concern, due to the very high performance ...
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7 votes
4 answers
916 views

Back up plan to use LOX-RP1 for Apollo mission

Today it might seem to be an hypothetical question. I read that Surveyor mission confirmed "re-igniting" a LOX+LH2 engine in space is successful. What if the use of H2 was not successful ? - ...
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6 votes
3 answers
275 views

Creating your own artificial gravity by running. (Part 1 - the basic idea)

The main motivation for artificial gravity is the astronauts' health Usually artificial gravity is supposed to work by rotating the spacecraft. See diagram A. Wouldn't it be much simpler to simply ...
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6 votes
1 answer
327 views

Is there some fundamental limitation that would prevent steam-powered rockets from reaching space?

According to the Discovery Channel (see CNN article below) the latest attempt to use compressed steam propulsion to get to 5000 feet ended in tragedy. It's not yet clear the altitude it reached, ...
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