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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Can I “tack” towards a laser beam from which I am powering my 100% efficient & massless ion engine?
As far as I know, for light and particles taking special relativity into account:
\begin{align}
E^2 &= (T + m_0c^2)^2\\
&= p^2 c^2 + m_0^2 c^4 &\text{ (particles)}\\[1.5em]
E &= p ...
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How should mass specific impulse calculated for relativistic exhaust?
This answer says:
Optimising for Isp only is problematic, as it's simply:
$$I_{sp} = \frac{v_e}{g}$$
Which is the same as optimising for exhaust velocity.
With no constraints on thrust, particle ...
3
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2answers
131 views
Lunar landing in cotton candy?
When spacecraft land on Earth, they use the atmosphere to slow down.
On the Moon there's no atmosphere, so spacecraft must instead use rockets to slow down from orbital velocity.
Would it be possible ...
asked Oct 24 at 14:43
SE - stop firing the good guys
24.5k2 gold badges86 silver badges156 bronze badges
2
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1answer
88 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 ...
2
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0answers
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Have capsule-free taxi spacecraft ever been seriously considered for non-emergency use?
Capsules are heavy, but necessary.
Or at least, they are necessary for launch, landing, and stays in space lasting more than an hour or two.
But it is possible to imagine situations where cosmonauts ...
asked Oct 22 at 16:46
SE - stop firing the good guys
24.5k2 gold badges86 silver badges156 bronze badges
1
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1answer
44 views
Who won the first round of Limitless Interstellar Initiative Grants?
Wired's NASA's EmDrive Leader Has a New Interstellar Project also mentions
White’s research pedigree may sound like it was cribbed from a mad scientist in a pulp sci-fi novel, but most of his work ...
2
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0answers
128 views
What would be the challenges for a settlement immersed in liquid fluorocarbon on Mars?
Perfluorononane is a fluorocarbon with a density of 1.8 g/mL and a melting point of -16⁰ C.
According to this paper it has a vapor pressure of about 0.7 kPa at 15⁰ C, so in regions with low altitude ...
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1answer
205 views
If Starship works, how much would it cost to create a system of rotable space mirrors that reduces temperatures on earth by 1° C?
There are many proposed geoengineering solutions that could reduce temperatures on earth. Unfortunately, a lot of them have a mix of side effects and lock-in effects where the changes in temperature ...
1
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1answer
131 views
Could pressurized ionized oxygen be used as a fuel source for an ion thruster?
I am wondering if a canister of pressurized oxygen could be used as a fuel source for an ion thruster.
To show how this could work on a conceptual basis, please reference the following drawing:
I ...
15
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2answers
1k views
Could one actually make a grain silo rocket?
Watching the recent SpaceX Starship tests got me to thinking:
Could you actually make a rocket using grain as the propellant?
Image from https://www.teslarati.com/spacex-starship-sn5-second-hop-plans/...
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0answers
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Could pressurized steam be an effective propellant for satellites?
If you had a small pressure vessel and a matte black external boiler that could utilize the heat of the sun, would pressurized steam be feasible for maneuvering a small satellite?
2
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1answer
163 views
Challenges that missile mail would have to overcome?
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 ...
5
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1answer
129 views
Semi-feasible alternates to silicon electronics for a Von Neumann Probe?
Disclaimer: this is a modified cross-post of my post on the Worldbuilding SE site, adapted to better fit the Space Exploration community.
Some background
A Von Neumann Probe (VNP) is a sci-fi probe ...
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1answer
228 views
Could a rocket's reentry capsule be slowed down by a centrifugal flyweight governor system? [closed]
I am wondering if a rocket's reentry capsule could be slowed down by a built-in centrifugal flyweight governor system that would make use of an air pressure differential to create an opposing force to ...
24
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3answers
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Why isn't SpaceX constructing the Super Heavy launch mount on top of the water?
With SpaceX creating their launch facility in Boca Chica Texas, right next to the water, why would they bother building a huge launch pad to withstand the blast, as opposed to building it on top of ...
3
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0answers
103 views
Mining Venus' surface using lasers?
One of the issues with colonizing Venus is the harsh conditions at the surface. People have proposed using floating habitats in the upper atmosphere, where conditions are milder, and gathering ...
4
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2answers
128 views
Capturing Hydrogen from the solar wind for Space Colony / Terraforming
Could we capture hydrogen from the solar wind instead of importing it or getting it from local sources ie water on mars or the lunar ice? Would it be worth the time vs energy used to get it?
Basically ...
1
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1answer
49 views
Plasma magnet drive for reusing stages
From what I understand, one of the reasons why it's impractical to recover upper stages of rockets is that they're traveling at high speeds, and methods of making them bleed off that speed (such as ...
2
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2answers
104 views
Create something for the module when it lands into the ocean to drive it to shore
Food for thought: SpaceX has designed its new aircraft. Why doesn’t their team, develop some thing that will allow the astronauts to drive the module back to shore?
5
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1answer
98 views
Water ice as dummy/filler payload to orbit
When I'm rich, and my reusable orbital launch program is well under way, I will be performing many orbital test-launches and paid satellite deployments. Once I've knocked out the bugs and optimized my ...
7
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0answers
125 views
If Elon Musk wanted to bring back some Martian soil, would US permission be required?
A scenario occurred to me recently where the Chinese space program decided to go all-in on Mars sample return, and their schedule was such that it would happen before the NASA/ESA mission was ...
5
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0answers
58 views
“Hybrid” statite design for a Dyson bubble?
One proposed design for a Dyson sphere is the Dyson bubble, which consists of statites (satellites that use light pressure to counteract gravity). In this design, the statites remain stationary ...
2
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1answer
127 views
What would be the most viable way to have constant communication with a Mars base?
I am currently working on a project involving designing a Mars base, and a major factor is establishing constant communication between Earth and the Mars ground base.
I am thinking of utilizing laser ...
5
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4answers
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Could a steam engine work on the moon? [closed]
Recently, there was a thread on Hacker News about building a nuclear power plant on the moon.
Humans being what they are, I could imagine some dark outcomes. Instead could we build a steam engine on ...
3
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7answers
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Would it have been cheaper and/or faster to put a James Webb-like Space Telescope on a balloon instead of a rocket?
I've just noticed the following items:
CNET: NASA to send stadium-size balloon skyward to study the cosmos
JPL/NASA News: NASA Mission Will Study the Cosmos With a Stratospheric Balloon Even in 2020 ...
2
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1answer
88 views
Rocket staging by use of strap on Boosters
Will it be advantageous to have multiple (say-3) stages of a rocket, arranged in a "strap-on" type SRBs' assembly, geometrically well distributed around the circumference w.r.t. their ...
4
votes
2answers
94 views
Ramscoop for a space station or lunar base?
From what I've read, the Bussard ramscoop has problems which make it impractical as a means of propulsion. However, would it be possible to use it for a different purpose? Could a space station or ...
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3answers
178 views
Using Venus' Atmosphere to Cool the Earth [closed]
The Starfish Prime nuclear test on July 9, 1962 caused massive fluctuations and degradation of the Earth's magnetic field. This field is largely responsible for redirecting the Sun's solar radiation. ...
0
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0answers
56 views
How is it possible to reduce the weight of a high-energy laser?
To provide some context..
I have designed an interstellar spacecraft called Solar One.
It employs a combination of 3 propulsion methods: nuclear fusion, beam-powered propulsion , and photon propulsion....
3
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0answers
75 views
Would rotating detonation rocket engines always require high pressure fuel pumps? [duplicate]
The question Performance of a pumpless liquid rocket engine is thoughtful and provocative and pretty much all answers include a mention of the extremely high pressure necessary to push propellants ...
5
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1answer
404 views
How much does launch costs have to come down to make chemical fuel deep space probes feasible?
Considering that NASA have been running short of plutonium for their RTGs, it makes sense to consider alternatives.
For the inner solar system up to Jupiter, solar cells have been demonstrated on ...
23
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9answers
10k views
If someone built a vacuum tunnel through the atmosphere, could you have an orbit with a sea level perigee?
This is something I've been thinking about for a while now. My initial estimates for the structure were based on people's estimates for an O'Neil cylinder, but assuming you can make the structure a ...
18
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6answers
4k views
Would a higher air pressure on the ISS or elsewhere make it easier to “swim” in microgravity?
What if the atmospheric pressure onboard the ISS was 5 atm, 5 times the pressure on Earth and currently on the ISS, while maintaining the breathable oxygen level, e.g. if the additional atmosphere ...
4
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1answer
314 views
What was the point of the Redstone rocket when there was the X-15 rocketplane?
Just a curiousity question, so don't get me wrong for I very much admire and have high respect towards the entire Mercury project, Alan Shepard (the first American in space, a national hero) and Gus ...
4
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1answer
390 views
Could the Dream Chaser or Space Shuttle fly/have flown to the Moon with boosters on the orbiter's side?
In the 1998 movie Armageddon the crews use Space Shuttles which have boosters also on the orbiters' sides (two boosters per orbiter) in order to get to the Moon and to the asteroid. Upon descent onto ...
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3answers
162 views
Prior to putting spacecraft on a trajectory going a significant fraction of the speed of light, would some things need to be tested on Earth?
Except for particle accelerators, I don't think we have made any macro object go anywhere near the speeds planned for spacecraft like the one planned in Project Orion.
But would there be something ...
1
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0answers
66 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 ...
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1answer
70 views
stage 2 possible hollow cylinder design
I was watching this video from Everyday Astronaut:
In the video, it highlights why Stage 2 landing is considerably more difficult than stage 1 landing. There is a 1:...
5
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2answers
236 views
What are the challenges in recovering Falcon 9's second stage this way?
The Falcon 9's second stage is currently disposed of each flight. I know there have been some concepts by SpaceX on making it reusable, but evidently they have not yet done so. From my understanding, ...
2
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1answer
132 views
Have engineers designed a docking procedure that uses a boom/pole that “catches” the target and pulls itself in?
Watching Dragon/Endeavour dock with the ISS, I was curious as to how they used thrusters to orient the spacecraft and “soft dock” with the ISS. The narrators didn’t mention what happened after the ...
3
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0answers
139 views
Why is the Fuji capsule design philosophy not seen in other proposals?
Fuji is my favorite unflown dead spacecraft proposal (narrowly beating out Dynasoar). I am well aware of why Fuji has its weird/unique design, but what I'm curious about is why it's unique. In my ...
3
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1answer
101 views
Could the kinetic energy in the Sun's solar wind power an ion propulsion system for an interplanetary spacecraft?
I am wondering if the kinetic energy of the Sun's solar wind could energize heavy ions to the point in which they would produce enough momentum to propel an interplanetary spacecraft.
To help ...
6
votes
1answer
152 views
Is methylsilane CH6Si ever considered as fuel in rocketary?
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, -2612KJ/mol or 56.8 MJ/kg (better ...
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3answers
135 views
Would the trajectory of a comet be altered by attaching a parachute to it?
I am curious to know if the trajectory of a comet that is on a collision course for Earth could be altered by simply attaching a parachute to it. The parachute interacting with the comet's tail should ...
2
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2answers
99 views
Using heated water as propellant for a DT-He3 fusion thruster
Not sure if this would be best placed here or in World building SE, but I'll try here.
Let's say I have a Dueterium-Helium 3 fusion pulse engine (similar to what is in the Expanse) that will use ...
0
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1answer
126 views
Would the Poynting–Robertson effect ever be faster than a solar sail from a 1 AU orbit to the Sun?
In this answer to Do you need 0 km/s velocity to crash into the sun? I mention solar sails for retrograde thrust and the Poynting–Robertson as two ways an object could ever-so-slowly spiral into the ...
4
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0answers
73 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 ...
7
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5answers
1k views
Could moon ice be used to fuel a steam powered jetpack for EVA in space or high altitude exploration on the moon?
For long term moon operations, would it be practical to have a jetpack that used steam as a source for EVA on the moon surface and above it in orbit?
I imagine a scenario where lunar ice deposits ...
2
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1answer
98 views
Would an incandescent light bulb be more efficient than a laser for photon propulsion?
In an incandescent light bulb pretty much almost all of the input power is radiated as photons. While perhaps 10% of the power is useful for human vision and the rest are longer wavelengths, it's all ...
2
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1answer
115 views
Could a carbon arc lamp help to propel a spacecraft through interstellar space?
I would like to know, on a theoretical basis, if the electron flow entering into the anode of a carbon arc lamp would impart enough kinetic energy to the anode, and thus to the spacecraft, to help ...
