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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7 votes
2 answers
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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 ...
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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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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, ...
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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 ...
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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....
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  • 7,716
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 ...
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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 ...
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  • 148k
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 ...
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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 ...
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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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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 ...
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  • 148k
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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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?
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  • 723
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 ...
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  • 419
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 ...
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  • 111
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 ...
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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 ...
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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 ...
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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 ...
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  • 6,410
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 ...
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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 ...
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  • 7,052
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 ...
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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 ...
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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 ...
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  • 141
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. ...
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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 ...
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  • 1,079
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 ...
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  • 1,079
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 ...
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  • 1,079
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. ...
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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 ...
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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 ...
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  • 148k
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 ...
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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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  • 148k
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 ...
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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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  • 3,579
2 votes
2 answers
95 views

Could a laser array and miniature light sails be used to deflect asteroids that are on a collision path with Earth?

Several projects related to interstellar travel have been proposed, like interstellar travel with miniature light sail starships , or the Breakthrough Starshot project Question. Could a laser array ...
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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 ...
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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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  • 148k
7 votes
2 answers
259 views

Is there an example of a classic space engineering moment where months of work had to be discarded due to the wrong approach?

Is there any classic aviation/space engineering moment where the engineers had been working on a concept for months and then realised that their approach to the problem wasn't quite right and so had ...
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  • 365
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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  • 369
2 votes
0 answers
63 views

Could this three-thruster spherical spacecraft de-tumble itself with zero final velocity?

@Joshua's answer to What is the minimum number of RCS thrusters capable of stabilizing a satellite against an arbitrary rotation? begins: I know this question is old, but I randomly discovered a ...
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  • 148k
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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  • 3,190
4 votes
1 answer
145 views

Can rocket engines which use hypergolic propellants be augmented with LOX for increased efficiency?

Hypergolic rocket engines typically use NTO and hydrazine based propellants. Wikipedia page on Liquid Rocket Propellants shows N2O4 and N2H4 at 1.36 ratio to have 286s Isp at sea level. My question is ...
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  • 2,281
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. ...
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  • 1,072
2 votes
0 answers
27 views

Alternative small mass payload transportation from the moon to L5 besides rail gun and mass driver?

This question asks about a low cost transportation from the lunar surface to a space settlement at L5. Moon mining is can be a revolutionary breakthrough in sustaining a space economy, but large scale ...
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1 vote
1 answer
95 views

Looking for a ballistic projectile technology development company I'd read about a few years(?) ago

I recall reading a few years(?) ago about a ballistic projectile technology development company that expressed interest in launch capability as well as applications closer to Earth. In a comment below ...
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  • 148k
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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  • 148k
3 votes
1 answer
451 views

Conversion of heat into electricity in rocket nozzles

Can we use advanced thermoelectric materials to reduce the temperature of nozzles by converting heat energy to electric energy and reducing the strain on the nozzle material and the coolant while ...
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  • 69
-3 votes
3 answers
235 views

energy needed to accelerate in space

I was thinking about possibility of cargo transport between, say, earth and mars when a “pusher” accelerates propulsion-less cargo vessel, which is catched and decelerated at the other end of ...
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  • 105
1 vote
2 answers
112 views

Using inflatable balloons to collect hydrogen from space as a simple solution for radiation shielding

I've seen this video where around the 4:59 mark it states hydrogen is the "best element" to protect humans from cosmic rays: Even if it's not completely true,...
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