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Questions tagged [energy]

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

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3answers
11k 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?
20
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6answers
4k 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 ...
20
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2answers
616 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, ...
19
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4answers
3k 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 ...
19
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2answers
1k views

What types of sustainable energy are available beyond Mars?

Most of the energy we use on Earth in our daily activities is a derivative of solar; wind, hydroelectric, coal, gas (oil), wood fire, solar cells. While we might not think about it, all of these are ...
19
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3answers
395 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 ...
18
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2answers
2k views

How far from the Sun can solar power be used as a reliable energy source?

Space probes headed for the far reaches of our Solar System rely on radioisotope thermoelectric generators for power (Cassini–Huygens, Voyager 1, Voyager 2). Presumably this is because solar power ...
17
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1answer
404 views

How will Curiosity manage its power when its nuclear power starts to run low?

As we've already determined, Curiosity should last about 14 years on its nuclear power. What happens near that timeframe? Will NASA start to manage the rover's use of power by shutting down unused ...
16
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6answers
4k views

Methods for propulsion other than rockets for leaving Earth's atmosphere?

Due to the large amount of energy required, the standard method for leaving the Earth's atmosphere is rocket propulsion. Is there any other methods in development that don't involve rockets? E.g. ...
16
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2answers
2k views

Would geothermal energy be practical on a lunar base?

Given sufficient liquid in the form of water or other suitable medium, would the use of geothermal energy be practical or feasible for powering a lunar colony? Wikipedia (referenced) gives an ...
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 ...
14
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1answer
9k 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'.
13
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2answers
349 views

Is solar system active cryovolcanism a potential viable power source for future colonies?

According to Geology.com's web-article Active Volcanoes of Our Solar System, there are several volcanically active regions in the solar system asides from the Earth. In particular, the satellites ...
12
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2answers
444 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 ...
12
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1answer
183 views

Does the hull of a spacecraft acquire a charge during its rapid ascent through Earth's atmosphere?

Known fact: Heat causes a charge to accumulate on the hull of a craft at reentry. Questions: Does the hull acquire a charge during the course of its ascent too? What magnitude is this charge? (My ...
11
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2answers
674 views

In space can the difference in temperature between the inside and outside, provide useful energy?

The Thermoelectric effect allows for electrical energy to be created, based on a difference of temperature. In fact the Radioisotope thermoelectric generator is based on this principal and does/has ...
11
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1answer
828 views

Practical Lunar He-3 mining approach?

There is a lot of popular talk that There may be huge deposits of Helium-3 on the Moon, and It could be used for very efficient fusion reactors. Unfortunately in the bulk of popular talk actual ...
10
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3answers
974 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 ...
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 ...
10
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1answer
2k views

Can we get energy from the motion of orbiting bodies?

Can we convert the motion energy of bodies (such as satellites) moving around a high-gravity objects (like Earth or the Sun) to some kind of usable energy?
10
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3answers
15k 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?
10
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1answer
353 views

Would it be feasible to use wind turbines on Venus?

It has been proposed on Earth to use airborne wind turbines, anchored to the ground and flying at high altitudes where wind is strong and consistent. On Venus, I would immediately say that anchoring ...
10
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1answer
314 views

What are the unique design considerations for space bound nuclear reactors (TOPAZ, SNAP 10-A), and their respective dangers?

While the US has claimed only sending one nuclear reactor (SNAP 10-A) into space, Russia has sent many. Here on earth we've adopted a Defense in Depth strategy to design for safety controls. Though, ...
9
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3answers
4k 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 ...
9
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2answers
679 views

Can the reaction wheels also be used to store energy?

My understanding is that the parts of a typical flywheel energy storage are pretty much the same as the parts of a typical reaction wheel subsystem -- both have a flywheel, electric motor/generator, ...
9
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2answers
647 views

Could Earth-lunar flybys be repeated consecutively without the use of propellant?

Ever since a recent orbital mechanics question, lunar flybys have been nagging me in the sense that there is obviously energy available in the system. I'm interested if you could get a repeatable ...
9
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1answer
3k views

What is the “launch energy” or C₃ measured in km² / s²

In some papers there is "launch energy" characteristic of spacecraft launched into space from Earth. Sometimes it is written as "C₃" (C3). For example, Ares V document lists "C₃" as equal or less than ...
9
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3answers
346 views

Alternative energy sources for inter-stellar probes?

Are there any alternative energy sources to power inter-stellar probes such as Voyager I and II developed or in development by any space agency? Plutonium (238-Pu) has a half-life of about 87,7 years,...
9
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1answer
951 views

Peltier cell as solar cell in space

There's a related question: In space can the difference in temperature between the inside and outside, provide useful energy? The problem with that one is that it relies on the concept of "hot inside"...
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 ...
8
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1answer
3k views

How do you slow down a solar sail?

From what I understand, a lot of the difficulty in using conventional rockets to move payloads to other planets is that the object needs to lose its velocity one way or another so it doesn't slam into ...
7
votes
1answer
262 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 ...
7
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3answers
258 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 ...
6
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3answers
3k views

Could steam be used as a efficient power source for a space craft?

Could water (steam) be used as an effective power source for a manned spaceship headed to Mars? The basic idea is simple... Heat the water on the sunny side of the spacecraft, allow the steam to ...
6
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2answers
280 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,...
6
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1answer
688 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 ...
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 ...
5
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3answers
686 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 ...
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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4answers
4k 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 ...
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
5
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2answers
461 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 ...
5
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2answers
196 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 ...
5
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1answer
227 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?) ...
4
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5answers
532 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 ...
4
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2answers
291 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 ...
4
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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 ...
4
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3answers
644 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, ...
4
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2answers
472 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 ...
3
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2answers
554 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)?