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Questions tagged [energy]

Questions addressing the energy requirement for space/orbit/interplanetary missions.

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3answers
16k views

How much Energy is required to put 1 kg in LEO?

I was wondering, what is the minimum amount of energy required to put 1 kg of payload into LEO?
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1answer
104 views

Why satellite’s solar panel wattage is often listed in specifications?

What is the purpose of listing the power output (Wattage) from solar panel, without the energy/power specification of batteries or other electrical storage devices? Do satellites often use the power ...
1
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1answer
105 views

Can a solar mirror increase an ion engine 's output?

Could an ideal size solar sail work as a parabolic mirror to increase the out put of an ion engine? Would the extra weight encumber the ion engine nullifying the increases sunlight on the ion engine? ...
5
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4answers
5k views

Solar panels on Mars?

I was wondering if a base on Mars could be powered by solar energy alone? Since Mars is further away from the Sun wouldn't that mean lower efficiency thus making solar not scalable? Let's assume a ...
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0answers
95 views

How much D2O does it take to power an interstellar generation ship O'Neill cylinder for 10,000 years?

Did I do the math right? I'm using full precision but write only 2 sig figs. https://en.wikipedia.org/wiki/Nuclear_fusion#Criteria_and_candidates_for_terrestrial_reactions ...
19
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4answers
4k views

Is wind-power a viable backup power source for Mars One?

A question related to What power source options provide reliable and sustainable power generation for a Martian Colony, particularly the answer that solar and nuclear based energy sources being the ...
1
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1answer
79 views

How feasible is wind energy generation on Mars? [duplicate]

Spacecrafts and rovers tend to have dust settled on their panel which leads to reduced power generation. If wind turbines could power the instruments, then the seasonality of solar power generation ...
3
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0answers
47 views

What are the tradeoffs of circularly unfurling solar panel over linearly deploying solar panels?

Martian landers like Phoenix and Insight uses circularly unfurling solar panels. The regular satellites make use of linearly unfurling panels. What are the primary reasons why linear unfurling ...
0
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1answer
159 views

“Free energy” moving the space elevator possible?

In this other question I have found the following: A space elevator can climb at a low, constant vertical speed (albeit for a very long climb), and gets its orbital speed for free [borrowed from ...
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3answers
5k views

Does the ISS need more heating or more cooling?

While reading the recent question 'Do exercise machines on the ISS generate electric energy?', I got thinking all of the exerciser machines generate heat (heat energy). So yes all exercise machine ...
5
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3answers
2k views

How come we don’t put a huge windmill-like machine in space? [closed]

I am new to this sight, but since space being a vacuum there is little to no air resistance at all making a windmill spin forever. There is no wind in space however, if you spin it once, it should ...
6
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2answers
319 views

What does Specific power [W/kg] of a Solar Array exactly mean?

I am trying to size (weight and surface) a Solar Array for a Mars Base (university project) and the main specification I get is Specific Power [W/kg]. However, I need to relate both weight and surface,...
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1answer
68 views

Can an Earth like planet support life by building a Dyson Sphere across a White Dwarf? [closed]

(Hypothetical Concept) But is it possible to depend on a white dwarf as our power source? Provided we harness its 99% of energy? Can life be sustained?(If it is possible we can easily colonize an ...
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2answers
238 views

Energy solutions for space [closed]

One of the primary methods of creating power in space is by solar panels. However upon reading more about silicon based solar panels I got to know how even small dust particles can ruin the whole ...
5
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2answers
510 views

What are the energy-to-mass ratios of some fuels/oxidizers, when including the oxidizer?

Energy-to-weight ratio is an important parameter. We would like it to be high so we don't have to carry around much fuel. Maybe you've heard some of the numbers for common fuels. Hydrogen is about ...
4
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2answers
432 views

Solar Flux on Mars Surface

Considering that the Solar Flux on top of Mars' atmosphere is 590 W/m2 (following the 1/r^2 relation for sunlight), how much of this incident light actually arrives to Mars. In other words, what is ...
8
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3answers
1k views

Would a solar windmill in space be practical?

From this question we know that solar cells be problematic the farther you get from the sun. We know that solar sails provide viable propulsion far from the sun. Would it be practical to use a solar ...
10
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3answers
1k views

Would a flywheel energy storage have a distinct advantage or disadvantage in zero or low gravity?

The Centrifugal Battery (flywheel as an energy storage device) has been around [a while]since at least 1857. This comment and geoffc's answer (batteries and Bearings) got me wondering what would the ...
2
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1answer
60 views

Energy needed to open/close entry points in a rocket

In general, how often are air locks opened on a rocket? How much energy is needed to open and close the entry point?
3
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2answers
561 views

In the absolute vacuum of Space, will an electric dynamo still work? [duplicate]

In the absolute vacuum of Space, will an electric dynamo still work? Can it produce an electric current if it is not inside (or being affected by) a magnetic field (like earth's magnetosphere)?
5
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1answer
267 views

What type of electrical wiring provides the longest life in space?

It sound like standard electrical wire as you would use in earth bound transportation would have a significantly shorter life in the vacuum of space. (See related Do plasticizers evaporate in space?) ...
5
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1answer
158 views

What is the distribution of ∆V amongst different stages of rocket flight?

How is rocket energy (or fuel consumption) is distributed between gaining orbital velocity gaining orbital height fight aerodynamic drag
10
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3answers
997 views

Do any realistic rocket systems use different substances for propellant and fuel?

In his Edge.org Annual Question response, Progress in Rocketry, George Dyson exults in the success of Blue Origin and SpaceX in landing their rockets after pushing them past the Kármán line, and then ...
14
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3answers
4k views

Can we transport energy through space?

I heard somewhere about a possible way to mantain power plants outside Earth. To transport energy, we can send it into space as electromagnetic waves through satellites to reuse them later. It may ...
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1answer
59 views

'Space Transit Habitat' source(s) of energy

What are the sources of energy for a Space Transit Habitat(manned) in terms of both propulsion( after passing over the Low Earth Orbit) and required electric facilities)through a 6-8 month voyage to ...
32
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3answers
12k views

About how long will Curiosity last on its nuclear power?

Curiosity, we know, has no little nuclear reactor, it has a RTG. Great! But how long will it last? For how many years will our little 1-ton friend be roaming around another planet?
3
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3answers
506 views

Power to grow food per person

Can I get a rough estimate of the power (in watts) needed to produce light to grow enough food for one person, using vertical farming of the kind proposed for space habitats? Any reasonable outpost/...
19
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3answers
400 views

Are there proven sufficient $^3\text{He}$ reserves in the inner Solar System to sustain fusion reactors for colonisation?

According to the NASA website Energy from the Moon, that assuming we perfect the helium-3 ($^3\text{He}$) nuclear fusion technology required, that $^3\text{He}$ would generate only a very slight ...
6
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1answer
701 views

How plausible are the predictions made by Stephen Petranek at TED?

Here is the talk in question He talks about getting to Mars by 2027. He talks about a device called a WAVAR which will extract water from humidity. He also talks about a device called MOXIE which ...
4
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2answers
537 views

In an ion thruster, does the temperature of the plasma drop after acceleration?

In the last discussion on why ion thrusters are so energy hungry(Why are Ion Thrusters so energy hungry?), people said that the system is not only supposed to ionize the gas but also heat it to ...
4
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3answers
651 views

Nuclear powered engines with LFTR technology?

According to this YouTube video which starts with a 5 minutes summary the Liquid Fluoride Thorium Reactor is an extremely safe alternative to the current ones. Not only Thorium is abundant on Earth, ...
22
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6answers
5k views

Why are Ion Thrusters so energy hungry?

Ion thrusters need a lot of energy. But I don't understand why. So, one thing I understand is that it takes a lot of energy to achieve a high exhaust velocity ( since kinetic energy is proportional to ...
1
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3answers
343 views

Why don't Ion thrusters use exothermic reactions directly to ionize the gas and Heat up the Plasma?

Ion thrusters require a lot of energy because of their high exhaust velocities. But why can't they just pump a mixture of hydrogen and xenon into the chamber, mix it with oxygen and burn it? Doesn't ...
1
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1answer
609 views

What is the relation between the rocket equation and work, energy and power?

Say, I'm given the data typical to the Rocket equation in its many variants: $\Delta v, I_{sp}, m_f, m_0, ρ, T$ (thrust) and the likes. And someone asks me "What's the horsepower of the space shuttle ...
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2answers
203 views

Is there a way to recover any of the energy of reentry of a Mars lander?

Is there a way to recover any of the energy of reentry of a Mars lander? Tremendous energy is generated as a craft enters the atmosphere – admittedly over a fairly short time - and only one time. We ...
7
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1answer
269 views

How efficient would it be for an outpost to use human-powered vehicles?

Considering how bicycles use human power very efficiently for transport, would it be reasonable for astronauts on an outpost on the Moon or Mars to use easily replaceable human-powered equipment, like ...
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1answer
169 views

Never reducing propellant for deep space propulsion [duplicate]

in this sketch suppose the velocity of ball is 0 and it is out from the system and stayed in 0 velocity due to two electromagnets and these two magnets are attached with two springs and both springs ...
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3answers
309 views

Never reducing propellant for space propulsion [closed]

In this sketch there is a gun system as a propellant chamber and we are using iron balls as a propellant. An electromagnet is attached on the other side of this engine .When we fire these Iron ...
3
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1answer
705 views

Efficiency of rocket launches?

So, a satellite launch takes a huge amount of fuel to launch a relatively small (compared to total rocket weight at takeoff) satellite into orbit. Obviously there is a lot of energy expended during ...
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0answers
81 views

Is it possible to absorb energy from solar flares

I've learnt that solar flares have so much energy in them, but is it possible to tap the energy from them?
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2answers
1k views

What's the total specific energy of RTG?

How many joules of electric energy can you draw out of an RTG battery over its lifetime - and what's the mass of that battery? (whole; shell, thermocouples, fuel and all.) (realizing, that the power ...
14
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1answer
10k views

Escape velocity for our galaxy

What should be the escape velocity for our galaxy and can we calculate it? For instance, if we assume that we don't know the mass of our galaxy, you may consider it as small 'm'.
4
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5answers
570 views

Dissipating large amounts of energy fast, in space

Currently, we have good methods of sustained, slow dissipation of energy through radiators. They take quite large area (and mass) per watt dissipated though. I know sublimators were used at least in ...
7
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3answers
269 views

Will space-based energy beamed to earth increase heat on earth?

A Japanese paper on beaming energy from solar installation on the moon to earth via laser and microwave recently made the rounds in the media. Would this, or any space-based energy system cause a net ...
12
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2answers
474 views

What is the status of concentrated solar energy (CSE) in space exploration?

The Cassini Environmental Impact Statement, Chapter 2 (page 53–54) describes the status of Concentrated Solar Energy in space: A 1981 conceptual study of the system impacts of using a concentrated ...
5
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3answers
2k views

Splitting water quickly to turn a water rocket into a H/O rocket at launch: could it work?

I was just looking at a small but impressive compressed air/water rocket that launches off of a metal rod that runs through the nozzle and spans 3/4 of the length of the rocket. As the team increased ...
5
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3answers
697 views

Could thermal energy be collected by dragging a thermoconductive device against the outer atmosphere

Atmospheric reentry is notoriously a difficult and HOT endevour. Could this thermal energy be used as an alternative energy source on earth? Could this be used through some sort of orbital charging ...
3
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3answers
225 views

Do (Or can) satellites help renewable energy companies? [closed]

Renewable energy, such as wind, solar, and geothermal, can sometimes be difficult to find optimal locations for. How are, or can, satellites be used to assist in finding the optimal locations for ...
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2answers
131 views

Would it be possible to generate electricty in space with a satellite in orbit

So just had an idea that could work but would require billions to build: Theoretically we could build a giant highway for satellites to orbit on but as they are orbiting they generate energy as they ...
20
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2answers
698 views

Is it possible to build a Dyson sphere or its variant in our solar system based on our current technology?

Dyson sphere, a concept coined by the physicist Freeman Dyson, is a solar megastructure built around our Sun to harvests most of the radiated energy from it. While this sounds impossible for now, ...