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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34 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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3answers
546 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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2answers
133 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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1answer
93 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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1answer
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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417 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
73 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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1answer
130 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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2answers
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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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60 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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893 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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1answer
123 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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341 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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0answers
24 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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1answer
71 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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1answer
427 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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3answers
209 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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2answers
95 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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4answers
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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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2answers
127 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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1answer
106 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
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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103 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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1answer
187 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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281 views

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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1answer
108 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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3answers
283 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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4answers
296 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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1answer
108 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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1answer
62 views

attitude thrusters sharing a common combustion chamber

Most smaller satellites and other larger but simpler space craft with a less demanding mass fraction tend to use cold gas thruster, importantly with a common or as few as possible pressure vessels, ...
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2answers
154 views

Using lasers to reach the Karman line

I've just seen this Anton Petrov video: New Type of Laser Levitation Could Help Us Explore the Mesosphere. It's about this new form of levitation that uses lasers to heat up the air underneath a craft,...
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1answer
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Why are Starship's tanks curved the way they are?

Since Starship has to feed its engines in two kind of situations : -during ascent, acceleration is colinear to Starship's longitudinal axis. -at the end of the belly dive, acceleration is normal to ...
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5answers
997 views

Earth Launch System with Water Propellant

Water based thrusters have been proposed (and possibly tested by now) for use in satellites and other in-space vehicles - see this NASA article. The idea is to perform electrolysis on the water to ...
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2answers
144 views

launch rocket like bullet from steam/air rifle?

I've included an image depicting how exhaust energy from a rocket launch can be recouped by turning it into a large scale pressure cooker by the use of some kind of platform=sabot (thanks @...
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2answers
226 views

Can we engrave on the Moon by focusing laser from the Earth?

I would like to know if it is possible to make an engraving or burning moon's surface by focusing high energy laser beam from earth?
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2answers
1k views

Can you Hoverslam without going vertical?

Problem of the day, that pesky Starship Hoverslam. Imagining a crazy (childish) contest to see who could flip at the lowest altitude and brake to 0 rate of descent and land, it was (hilariously) ...
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3answers
288 views

Have any rocket fuel systems actually been explosive, and could have detonated proper?

Never mind that this is the 18th question to have the rocket-explosion tag. To the question "Would the Dragon escape pod have survived this event?" asked about the AMOS-6 mission, Elon Musk ...
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3answers
155 views

Can we generate electricity from Martian sandstorms? If so can it be used for powering colonies?

Rapidly varying electric fields inside dust storms have been observed and studied for years. The winds in the strongest Martian storms reach 60 miles per hour.
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1answer
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What if we launched rockets from space using the slingshot method and centripetal force? Would that be possible?

Would we have to build a orbiting launch station that uses centripetal force to launch the rockets? Or a station that freely floats through space not in a planets orbit? Would something like this ...
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0answers
101 views

Can ten (or more) rockets be used together to launch one massive object?

With computer flight controls where they are today, what would stop us from building a relatively large space station on earth, but then using 10 or 20 or even 100 falcon heavy or Starship or SLS ...
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1answer
245 views

New Shepard payload capacity to orbit?

If the current Blue Origin New Shepard were modified as little as possible to work as the first stage of a two-stage rocket, what would be its maximal LEO payload? To put it in other words: out of all ...

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