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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147 views

Is it practical to deorbit debris with water? [closed]

In orbital space, things don't slow down due to a lack of air resistance. Would it be practical to release a starship worth of water (say, 100T) in an orbit that would intersect known debris? In ...
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68 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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135 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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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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116 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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126 views

Is UHMWPE a suitable material for Balloon Tanks and cryo storage on spacecraft?

SpaceX Starship uses balloon tanks, almost: the axial compressive strength is partially dependent on tank pressure producing tension in the tank wall. If the tank pressure is high enough, wall ...
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197 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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228 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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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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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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114 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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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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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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560 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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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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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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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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137 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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101 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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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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469 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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1answer
76 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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131 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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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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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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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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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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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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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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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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1answer
131 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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356 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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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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83 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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Has there ever been a deliberate "Find A Satellite" challenge?

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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435 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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215 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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97 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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Cyanobacteria as Life Support?

I'm aware that cyanobacteria are responsible for the Great Oxidation Event and are very effective at turning CO2 into oxygen so it stands to reason that with the proper nutrients for the bacteria, you ...
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133 views

Has anyone suggested using an electrically powered sling or centrifuge mass thrower as a form of electrically powered spacecraft propulsion?

Has anyone suggested using an electrically powered sling as a form of electric propulsion for a space craft? It might be a centrifuge type arrangement with a way to release part of or all of the ...
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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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118 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 ...
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1answer
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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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106 views

Is it possible to build a starship out of clay?

I know it may sound silly but my consideration is to reduce costs due to the amount of metal used in standard space ships. Wood/bamboo for framing and clay around it, that is it for the hull. I'm NOT ...
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202 views

Flying saucer shape rocket vs cylindrical shape rocket

Here's my hypothesis- Cylinder shaped large rocket is not suitable for vertical landing due to its high center of mass and bulky weight. However an equally weighing saucer shape rocket has more ...
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How do you "make" a soliton? (recent peer-reviewed theoretical work in FTL travel)

I've just read an Article on the new approach on Warp Drives Dr. Erik Lentz describes. Instead of creating a bubble with negative energy density, he describes a Soliton in spacetime, which he ...
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116 views

Potential Fusion Drive system calculation issue

I will start off by saying that this is an entirely hypothetical drive system with plenty of handwaving and optimistic physics. My question I think is fairly simple and may just be something that ...
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291 views

Why SpaceX want to land the rocket on the ground?

click for full size Won't it be easier and save a lot of money to just catch it or land it in a basket? So rocket coming down can open arm longer than the diameter of the high basket where it goes ...
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315 views

Starship: Maximum damage if hijacked and weaponised?

Any sufficiently advanced space technology is indistinguishable from a weapon of mass destruction if misused. In the event that SpaceX lost control of a Starship to EvilHackers, what's the most damage ...
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109 views

would using both skyhooks and rockoons together be useful?

If my goal with a particular rockoon platform is not for it to reach space on its own but rather reach the lower end of some kind of some kind of skyhook, would the baloon part of the rockoon be more ...

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