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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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 ...
7 votes
2 answers
304 views

Helium balloon as a rocket

This question is not about rockoons, which are rockets using balloons as launch platforms to start from a greater altitude. This question asks about using the balloon itself as the rocket, like a toy ...
9 votes
2 answers
427 views

How does Spinlaunch manage the counterweight right after launch?

Spinlaunch has successfully launched a suborbital test vehicle from a 1/3 scale demonstrator, see for instance aviationweek.com or space.com. While spinning up the arm, perfect balance is achieved ...
6 votes
1 answer
162 views

Can we use magnets to land a spaceship (Starship)?

Can we use magnets to land a spaceship (Starship)? We could give the landing legs a magnetic flat surface or something and then the controller can reduce the magnetic strength or in other words, ...
18 votes
9 answers
5k views

Would it be practical to catch a rocket's exhaust to reuse it as fuel?

It's been some days that i think that would it be possible to make a ship that looks like this? The idea is to catch the fuel as you go. Would this make any sense or the thrust would be canceled by ...
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 ...
2 votes
1 answer
300 views

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

Previously I'd mistakenly asked Would the Poynting–Robertson effect ever be faster than a solar sail from a 1 AU orbit to the Sun? when I'd meant to ask about the Yarkovsky effect which can be much ...
3 votes
1 answer
172 views

Has "parasitic radar" ever been used in space?

Synthetic aperture radar or SAR is becoming a hot field of Earth observation of both natural and human activity. It is very power hungry as the beam needs to deliver sufficient power over each square ...
10 votes
3 answers
397 views

Would it be possible to alter the orbit of one satellite, with the exhaust plume of a rocket sufficient to deorbit it?

SpaceX plan to launch Starships towards Mars; many of them. This will involve burning hundreds to thousands of tonnes of propellant in low(ish) orbit, since each may require several refueling steps. ...
0 votes
1 answer
240 views

Sharp nose or Blunt nose vehicle for higher reentry speeds?

Hypersonic Technology Vehicle 2 (HTV-2) is a crewless, experimental hypersonic glide vehicle rocket glider developed as part of the DARPA Falcon Project capable of flying at 13,000 mph (Mach 17.53, 21,...
2 votes
1 answer
65 views

Decomposing HTP through regenerative cooling for use in closed expander cycle

HTP or high test peroxide has a long history as a low cost and high reliability oxidiser, and has had a lot of recent attention for its pseudo hypergolic nature when passed over a catalyst bed. ...
3 votes
2 answers
257 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....
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 ...
2 votes
1 answer
223 views

Challenges that "missile mail" would have to overcome? (Aerophilately)

Mail delivery by missiles has been attempted but never really took off. I have read of some who made attempts to build a postal missile system, such as Stephen Smith of India, but I wonder about the ...
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 ...
15 votes
2 answers
1k views

How can cosmic ray muons be used to replace GPS for positioning information in 3D on Earth and underwater?

Task & Purpose's The Navy is testing a GPS-like device that doesn’t require satellites “The future is extremely bright for this line of research." begins: The Navy is researching a new ...
1 vote
1 answer
103 views

Using Chimborazo as a rocket launching platform

Please consider this. Chimborazo is a sleeping volcano at 01°28′09″ S 78°49′03″ W. Its peak is 6263 metres above the sea level and because it is very near of the equator, the peak is more than 2 ...
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 ...
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 ...
7 votes
2 answers
689 views

Are In-Flight Electrically Heated Steam Rockets Possible?

I wonder if a rocket that uses electricity from internal batteries to heat water in its tanks to high pressure would be able to use that pressure to take off. Is it possible? I've researched here and ...
3 votes
0 answers
149 views

Why did NASA never launch crewed Orion missions on a Delta IV Heavy to the ISS?

Following the successful EFT-1 mission, why didn't NASA start launching crews to the ISS on the Orion spacecraft? This question deals about why crews weren't sent to the Moon, but I wonder why wasn't ...
1 vote
1 answer
93 views

What are the forces affecting superconducting MRI-magnet on low-earth orbit and could you accelerate a satellite with these forces?

In superconducting magnetic levitation the magnet levitates on top of the superconducting material (Meisner effect). In space, the electric current of the solar wind should create a magnetic field ...
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 ...
1 vote
0 answers
48 views

Are there any projects of flying launch pads on high altitude ballons? [duplicate]

It is possible to fly up to 30 km with high altitude balloons. Is it possible to build an island there with launch pad on it? Will it help to fly to space?
22 votes
4 answers
3k views

Could an electromagnet be used to raise the apogee of a satellite orbiting Earth?

Suppose we have a satellite orbiting Earth in an elliptical orbit, which has an electromagnet inside it. As the satellite goes from its apogee to its perigee (i.e. losing altitude), it turns on the ...
11 votes
2 answers
5k views

Could sheets of stacked graphene be used as part of a heat shield, since its melting point is 3000k to 5000 K

Since graphene material is the strongest manmade material, with "magical" properties, I wonder if it could be considered for use as a heat shield, since its melting point is 3000 to 5000 K ...
0 votes
1 answer
148 views

Do two opposing centripetal forces still cancel each other out in space? [closed]

I've conducted a test with two fans connected to each other. The top fan was setup to spin counterclockwise and the larger fan spun clockwise. In my test, it showed that once the two fans reached the ...
3 votes
2 answers
216 views

Can ISS trash be used as reaction mass for orbital maintenance

There have been a number of videos posted about trash being hand-pitched out the back of the ISS. This seems like a waste of potential reaction mass, especially since it cost $20,000/kg to get it up ...
0 votes
1 answer
122 views

Can Vacuum nozzles be used as cooling radiators in LEO?

Radiators are used for thermoregulation of spacecraft. https://www.academia.edu/934756/Thermal_Control_Handbook . Their effectiveness requires their surface be exposed to deep space, not an IR ...
2 votes
2 answers
262 views

Space elevator/tower through magnetic repulsion? What are the technical problems?

As more material weight leads to higher stress for a space elevator I have been asking myself if a kind of tower thats based on magnetic repulsion would not be an alternative. While I know that ...
5 votes
1 answer
240 views

Has anyone explored using sound as a heat shield?

I edited original post to better reflect question. I was looking around to see if anyone had explored the idea of using (Ultrasonic or Hypersonic)sound to deflect heat from a ship. Specifically sound ...
3 votes
0 answers
54 views

Could not an adapted RASSOR appear to be crucial for the Perseverance rover to find possible biosignatures on Mars?

Is it not very likely that most of the material that could contain possible biosignatures, like clays and carbonate containing minerals, will be below a layer of dust or regolith on Mars ? That the ...
5 votes
3 answers
1k views

Where to send invention ideas?

I invented a new type of thruster for satellites. I would like to know where can I send the report I made. The report was reviewed by several physicists and engineers in my environment, but I would ...
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 ...
3 votes
1 answer
166 views

Can the cryogenic expansion of liquid oxygen and liquid hydrogen be used to pump a rocket engine?

A common fuel amongst rockets is that of the combination of cryogenic liquid hydrogen and liquid oxygen. I looked at the design of a simple rocket using this cocktail that is the propellant and found ...
4 votes
0 answers
149 views

Exterior "running lights" on ISS?

In Scott Kelley's memoir "Endurance," he describes how challenging it is to navigate the exterior of ISS when in Earth's shadow, and he mentions that his Russian colleagues would just stay ...
4 votes
3 answers
573 views

Merging Shuttle and External Tank to reduce reentry heating

The Space Shuttle needed a high-performance heat shield that caused much grief over it's operational life. Having a large surface area on a reentering vehicle reduces temperatures by causing the ...
22 votes
6 answers
5k views

Why is it not concerning from a cost perspective to have so many engines on Starship?

Starship is meant to imitate (to a degree) the affordability of passenger jets. This applies to Earth-to-Earth travel as well as space travel. Jetliners started with 4 engines, but have since migrated ...
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 ...
18 votes
5 answers
5k views

Exactly why does Starship need to be this big for interplanetary travel?

As discussed in several answers to Isn't Starship way too big? Starship's unusual size is due to it being intended for missions to the Red Planet. But why? Even a smaller ship could satisfy the ...
4 votes
0 answers
55 views

Giving rocket propellants an opposite charge for perfect mixing?

One of the challenges in achieving theoretical efficiency is the mixing of both an oxidiser and fuel. This means separating both propellants from each other whilst pairing them with their counterpart. ...
1 vote
1 answer
109 views

When was advertising on Earth from space first proposed? By who?

How big will a space billboard have to be to be visible? can be seen to raise an interesting question. Question: When was advertising on Earth from space first proposed? Who proposed it? This can ...
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 ...
0 votes
2 answers
156 views

Can we land on an asteroid and ride on it?

If we could land on an asteroid, not necessarily a human, we would save the fuel consumed for flying the spacecraft and we will benefit by having the systems on it running for a very long time.. If ...
7 votes
1 answer
1k views

Using coolant as 3rd propellant

Rocket engines often have 2 propelants, one of which is used to cool the engine and after that the hot propellant is injected in the combustion chamber. Would make sense to have a third propellant ...
10 votes
1 answer
532 views

Why is the Otto II monopropellant fuel not used in spaceflight applications?

Is anyone familiar with the chemical/thermodynamic properties of Otto II fuel (a monopropellant used in torpedoes)? It is composed of nitrated propylene gycol with a couple additives that make it non-...
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 ...
2 votes
1 answer
85 views

Fan powered turbo-pump for low altitude/missile engines

There are many different liquid rocket engine power cycles, forxing propellant into the combustion chamber with tank pressurisation, gas generators, and heat exchangers, amongst others. Instead of ...
6 votes
1 answer
323 views

Could a solar sail composed of smart glass stay near the L1 point of Venus?

From answers to this question i've learned that the Lagrangian L$_1$ point of Venus is not stable, despite the almost circular orbit of the planet and the fact that it has no moon. Nevertheless would ...
3 votes
1 answer
141 views

Why aren't ISS attitude control thrusters a "tool" picked up by robotic arms?

Since ISS is an evolving structure which center of mass flucuates in position depending on added or removed modules, could Canadarm or latest European robotic arm be used to manipulate attitude ...

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