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Questions tagged [energy]

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

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1answer
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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 ...
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1answer
93 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? ...
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0answers
92 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 ...
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1answer
63 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 ...
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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 ...
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1answer
150 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
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 ...
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1answer
66 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
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 ...
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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 ...
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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?
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2answers
224 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 ...
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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,...
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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)?
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1answer
226 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?) ...
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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
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1answer
55 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 ...
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3answers
421 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/...
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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 ...
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3answers
304 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 ...
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1answer
529 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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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 ...
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4answers
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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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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 ...
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1answer
165 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
300 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
671 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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76 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 ...
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 ...
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3answers
685 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 ...
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5answers
531 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 ...
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3answers
211 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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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 ...
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2answers
127 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 ...
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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 ...
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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 ...
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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, ...
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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 ...
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1answer
261 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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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 ...
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1answer
819 views

Could the Hubble mirror be used to create a laser to propel solar sails?

Would a space based magnifying lens (such as Hubble) be more efficient than a space based parabolic mirror to propel solar sails?
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0answers
75 views

Energy use of Asteroid Redirect Robotic Mission (ARRM)?

In the ARRM feasibility Study Table 4, parameters of four different options (three different launchers and different trajectories) are gathered. What would be the total energy use of a mission like ...
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2answers
1k views

How much energy is required to send a payload of 40 t from Earth's surface to LEO?

I am confused with energy requirement equations... Am I anywhere near with my following assumptions: $\Delta v$ from surface to LEO is 9000 m/s typical exhaust velocity $v_e$ = 4500 m/s and mass of ...
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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, ...
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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 ...
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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, ...
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1answer
367 views

Assuming that gravity modification technology will be possible, could a mission reach Kepler - 186f (for example) in a human life span? [closed]

In order to understand my question, the following references must be studied. There is an article that you might want to read, the article was written by Sebastian von Hoerner, "The general limits ...
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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?
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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 ...