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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2 votes
1 answer
71 views

Propellantless propulsion in gravity field

I have a proposal for a following propellantless maneuver. It is propellantless in sense that no mass is lost from spacecraft. It is not reactionless as spacecraft interacts with planet through ...
3 votes
2 answers
317 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 ...
1 vote
0 answers
70 views

How heavy is an orbital pogo stick?

Moving people from a A to B in space often requires a significant change in velocity, requiring propellant eating into the mass budget. But most of this propellant is "wasted" in moving a ...
1 vote
2 answers
665 views

Lorentz force space propulsion

While browsing for Space propulsion, I've found the following article As shown in Figure 2, the conductor I0 gets through the coil L0, and they are fixed together and form a system. a is the main ...
1 vote
1 answer
66 views

Is an open expander cycle rocket engine driven by a gasified oxygen turbine technically feasible?

Is an open expander (bleed-off) cycle engine that uses the gasified cryogenic oxidizer instead of the gasified fuel to drive the turbo pumps technically feasible? I was thinking of a first stage open ...
6 votes
4 answers
677 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 ...
2 votes
1 answer
147 views

Can propellant tanks in a pressure-feed rocket be pressurized by burning the propellant inside those same tanks? Recipe for Ka-BOOM?

Pressure-fed liquid fuel rocket engines use pressurized tanks to deliver propellant to the combustion chamber, rather than pumps. This eliminates the mass, cost and complexity of the gas generator and ...
2 votes
3 answers
416 views

Is there any kind of research on *sub*-orbital rendezvous-ing with a space tug outside the atmosphere?

The key difference with a plain old-fashioned orbital rendezvous would seem to be that there'd be limited time to only briefly match velocities and trajectories: Let's say a vehicle launched from ...
5 votes
1 answer
321 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 ...
6 votes
3 answers
243 views

Can we dig for air pressure on Mars?

Digging 8km under the lowest point on Mars will get us Mount Everest conditions for air pressure. I was thinking of two ways of doing said title: Nuclear powered bulldozers working around the clock ...
2 votes
2 answers
201 views

What policies and capabilities are in place to induce hypothermia for the purpose of reducing hypoxic brain damage in EVA depressurization?

Depressurization incidents during EVA will have hypoxia as the ultimate cause of death or permanent brain damage. If an astronaut’s brain is deprived of oxygen, irreparable damage occurs after about 4 ...
9 votes
6 answers
4k views

Orbital Supercomputer for Martian and Outer Planet Computing

As we know, computing will (and really has) been important to research missions for space science and exploration. I read about the Spacebourne Computer program HPE and NASA used for the ISS as proof ...
1 vote
2 answers
241 views

The costs of a single SLS solid fuel rocket booster

Why didn’t Nasa cluster four solid fuel shuttle boosters around an Atlas V booster. The thrust would be substantially more than that of the SLS, with no fueling problem on the launch pad. It would be ...
2 votes
1 answer
173 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 ...
3 votes
2 answers
397 views

Could a Robert Goddard style motor mount be used for powered landing of SLS solid boosters?

The thought of pairing SLS solid boosters on just about anything one wants into orbit led to the thought of recovering them on barges at sea. We all remember Robert Goddard's top mounted rocket engine ...
-1 votes
1 answer
75 views

Could Spin Solve Needs for a Hot Water / Steam Rocket?

Instead of the old concept of nuclear thermal steam rocket, could we use spin in a pill shaped rocket to provide structural integrity, flight stability, energy storage, artificial gravity, and ...
4 votes
0 answers
136 views

Cooling an aerospike spike via "fuel diversion"?

My question is, could an aerospike be cooled via diverting a very small quantity of your fuel (fuel used since it has a higher heat capacity than oxidizer and won't, you know, turn your engine into an ...
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 ...
2 votes
0 answers
55 views

"Semi" hybrid rocket? Throttleable solid fuel rocket?

Are there any published examples of "hybrid" rockets that used a propellant grain of mixed solid fuel and oxidizer where the injected component was only needed to sustain the burn without ...
2 votes
1 answer
175 views

Lunar Starship descent motors' tank design

Just recently NASA has announced the Lunar Starship as the winner of the Artemis lunar lander contract, which I have to say I'm very excited about. In the latest render however, the nose cone of the ...
14 votes
4 answers
1k 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 ...
2 votes
2 answers
157 views

Orbital Chinese firework-cluster

I remember when I was younger I had heard this story about the Chinese using primitive fireworks, and even strapping them to a bamboo glider in an attempt to reach the moon. This story probably isn't ...
2 votes
0 answers
103 views

How do different stages attach to each other?

I started learning about rockets recently, and while searching for information, I found some ways that different stages separate, but I wandered if it was possible that they could reattach to a ...
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 ...
9 votes
0 answers
246 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 ...
6 votes
1 answer
578 views

Why aren't smaller fairings used for smaller payloads?

I saw this picture of the DART spacecraft being encapsulated in its payload fairing. Why doesn't SpaceX manufacture a smaller (shortened or thinned) fairing for the spacecraft? It reduces mass and is ...
1 vote
1 answer
208 views

Would ejecting propellant close to light speed result a '"dream engine"?

"Dream engine" I assume as pictured in the old science fiction: a single stage rocket that can take off from the Earth and then freely travel at least over Solar system, landing multiple ...
7 votes
1 answer
521 views

What would be the challenges for a 50 km long tether to the surface of Venus to get recurrent samples from there?

Basalt fiber would be an excellent material for a tether in the atmosphere of Venus because it could withstand both the acidity and the high temperature near the surface there. From this answer about ...
-2 votes
3 answers
303 views

Why fly to the moon when you can fly away?

I am not a NASA employee or a scientist, but why do we fly to the moon when it looks easier to fly away from it and wait for it to approach the craft. Then put something permanently in a polar orbit ...
0 votes
2 answers
189 views

Could a Stirling engine be used to produce more electricity in space?

A Stirling engine (https://en.wikipedia.org/wiki/Stirling_engine) is an engine which uses temperature differences to turn. In space it is hard to conduct heat so very often the sunny side of an object ...
0 votes
1 answer
120 views

Spacewalk From Earth To Luna [closed]

A question that I have not seen but have been curious about…… I have a little bit above average (I think) of how gravity works or what gravity is but can’t figure this out; Let’s pretend that we make ...
3 votes
1 answer
110 views

"Tandel Missile" design with engines forward of their fuel tanks

Whilst looking for something else entirely, I came across this amazing looking rocket design mentioned in passing on this nasaspaceflight.com forum page, talking about the San Diego Air and Space ...
7 votes
2 answers
638 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....
-4 votes
1 answer
159 views

Could using magnetism principles aid us in achieve near speed of light travel

Could a vehicle with ferrous properties be passed threw a hollow tube, that had coils spaced out in intervals, and which produced strong magnetic field in the vacuum of space, create speeds close to ...
1 vote
0 answers
151 views

Would a ring system for the Earth be a net benefit in terms of climate change? Is an artificial ring feasible? [closed]

The greenhouse effect as I understand it is because sunlight hits the Earth, and is re-radiated as infrared heat, which is then trapped by greenhouse gasses in the atmosphere, like CO2 and Methane. So ...
1 vote
1 answer
141 views

Collecting suns cosmic rays

Is it possible to collect the Sun's cosmic rays positive and negative particles in different coils , using electromagnetic coils, 50 meter diameter collimating coils with solar cells to power the EM ...
0 votes
2 answers
239 views

Is rail gun conversion possible? [closed]

can a rail gun be converted into a "High Velocity Pulse Engine",to be used as a "Jump Drive" to achieve light speed capabilities.
8 votes
1 answer
326 views

Has methylsilane (CH₆Si) ever been considered as fuel in rocketry?

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, -2612 KJ/mol or 56.8 MJ/kg (better ...
9 votes
3 answers
376 views

Would this Starship design alternative be viable?

Considering Starship's atmospheric entry, belly dive and "bellyflop", latest iteration displays four aerodynamic surfaces, two aft fins and two canard fins. Soon, this configuration will be ...
0 votes
1 answer
206 views

Why aren't clusters of F-15 or SR-71 engines used for a boost stage for rockets? [duplicate]

A cluster of say 8 F-15 or SR-71 engines in my mind could make a viable first stage for a small rocket. Second they can land the stage back to the ground and if my guess is right they could go to up ...
36 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 ...
7 votes
2 answers
406 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 ...
6 votes
1 answer
215 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, ...
9 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
317 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 ...
10 votes
3 answers
407 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
338 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
90 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
308 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 ...

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