Questions tagged [power]

Questions regarding energy used to operate a mechanical or electrical device.

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22
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1answer
1k views

Why did Apollo spacecraft use both AC and DC equipment? Still used in present and future designs?

Why did the Apollo spacecraft use both DC and AC power, requiring heavy inverters? Was it impractical to design everything to run on DC power only? Why? Are both AC and DC power still used in present ...
2
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1answer
242 views

How can satellites serve a large number of devices on earth?

Say we have a LEO satellite. There are 5000 low power devices on earth (They are in the close vicinity, can be served by same satellite) which needs to be communicated with the satellite. Now my ...
19
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3answers
2k views

Potential high temperature power sources for a Venus lander

What power sources are viable on a 'long term' Venus lander? An RTG relies on a temperature differential, and is not likely to be doable with a 457C 'cold side'. Based on this answer there is not ...
3
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2answers
292 views

How to transport gigawatt-level power across a 100km distance?

I'm investigating the idea of transporting gigawatts of electrical power to the first stage booster of an electrical rocket. The first stage booster, like Falcon 9's recoverable first stage, stages ...
12
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5answers
6k views

Can cosmic background be harvested for energy?

I know it would be awfully weak, but it's present even where all other power sources would be unavailable - could cosmic level radiation be used to power minimal set of systems of a probe, say, a ...
1
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1answer
1k 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 ...
3
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2answers
540 views

Tritium as energy source for probes?

There's this ingenious little hack video: "How to make tritium nuclear battery at home". The idea is very simple: "tritium keychain lights" - tubes with tritium and luminophor - placed between solar ...
8
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3answers
315 views

What kinds of nuclear reactors are suitable for operations in space? (Beyond thermionic and RTG)

If we want a nuclear power plant in space with a capacity similar to that of a conventional water boiling turbine nuclear power plant on Earth today, what kinds of fundamental design changes would ...
24
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3answers
2k views

Why are RTGs different colors?

This is an image of the radioisotope thermoelectric generator (RTG) for Cassini: This one was for one left on the Moon: And this one is for the Multi-Mission RTG, used by Curiosity on Mars: One is ...
3
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2answers
206 views

Power requirements for solar electric interplanetary vehicle

I am interested in electric propulsion for manned interplanetary craft. There must be a lot of models for a craft able to travel to Mars, for instance. I am wondering what the power requirements seem ...
9
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1answer
473 views

How much power would an Alpha Centauri probe require for communication?

Project Longshot report (1988) says: A laser with an input power of 250 kilowatts would allow for a data rate of 1000 bits per second at maximum range." Yet Breakthrough Starshot website (2016) ...
3
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2answers
304 views

Temperature of photovoltaic cells vs efficiency - is it ever actively controlled?

The efficiency of photovoltaic cells is surprisingly strong function of junction temperature. Hotter usually means lower efficiency. If one searches for example for images and sites tagged with "...
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2answers
159 views

Has the choice of photovoltaic junction types for newer spacecraft converged on one, optimal solution?

On earth, the photovoltaic cell junction for mass production tends to be just silicon, although there is a variety of material types - single crystal vs multicrystal or polycrystal, or even amorphous. ...
10
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1answer
522 views

Do geosynchronous satellite launches require a tight launch window?

I thought only launches to rendezvous (resupply, repair, space station expansion etc) and direct launches into interplanetary trajectory require precisely timed launch window. Then I read: Geosync ...
2
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3answers
542 views

Would it be possible to power a Venus lander using a temperature differential?

Venus has an average surface temperature of 735K. Would it be possible to harness this extreme temperature and use it to generate electricity? After all, that's the principle a radioisotope ...
54
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4answers
6k views

Why wasn't an RTG used on the Juno spacecraft?

When I first heard about the Juno spacecraft, I was surprised that it would be using solar panels to generate power throughout the mission. Why wasn't a radioisotope thermoelectric generator (RTG) ...
7
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2answers
596 views

Solar cells in series

Most of space-based hardware operates on solar panels composed of lots of photovoltaic cells connected in short series that produce around 28V; lots of these are connected in parallel to produce ...
12
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2answers
2k views

Are cubesats deployed with fully discharged batteries? Even those on Sherpa?

I'm pretty sure that at least some large satellites are deployed with their batteries charged so that they can initialize themselves, get their own attitude and position, and possibly establish some ...
14
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2answers
5k views

WHY did Rosetta have to go into hibernation for 2.5 years?

It seems the Rosetta spacecraft was put (put itself) into hibernation 08-June-2011. It spun itself up to stabilize its attitude, then shut down navigation, attitude control, communication systems as ...
5
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2answers
399 views

Can Red Dragon generate electrical power after a Mars landing, or will it rely only on battery power?

Red Dragon will presumably have to shed or re-stow solar arrays before any landing. What will be the source of electrical power after landing?
3
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2answers
118 views

Lessons Learned - What can space power system design teach Antarctic remote sensing systems

I know that a lot of brilliant engineering has gone into developing the space technology that we have. So, what engineering lessons about dealing with extreme cold and portable power sources do you ...
1
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0answers
73 views

Is there an upper limit for thrust generation by ion propulsion? [duplicate]

I was just reading an article about how the main factor preventing ion propulsion from being more effective is power generated from solar arrays. Solar arrays typically only generate 1-5 kW of power, ...
7
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3answers
1k views

Alternator/generator on launcher engines?

In Kerbal Space Program, most liquid fueled engines include a generator which provides electricity to systems on the rocket, keeping the batteries topped up while on ascent. Do any real rockets (...
1
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1answer
2k views

Why do satellites never run out of power?

Why do the satellites never run out of power do they have batteries that are charged by sunlight everyday? Also they transmit so much information across the globe.
2
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1answer
285 views

What are the challenges in building a supercritical CO2 gas turbine power plant for a Mars habitat of 6 astronauts?

There is abundant $\require{mhchem}\ce{CO2}$ in martian atmosphere, so we could use that in a modified gas turbine. Can this, combined with PV cells (a hybrid power source), be an efficient energy ...
2
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2answers
520 views

Could chemical energy quicken ion propulsion?

Background Tsiolkovski's rocket equation says that change of speed is proportional to the exhaust velocity. Chemical propulsion seems to have a strictly limited and since long achieved maximum ...
9
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8answers
1k views

How could a fast powerful rover on Mars be powered electrically?

Background The rovers on Mars are slow and weak. If I am to believe what I read, MSL Curiosity only produces 1/6th of a horsepower electric effect, 125 watt. In order to perform tasks like deep ...
7
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4answers
2k views

Why aren't solar collectors in space solar power concepts placed closer to the sun?

I've been thinking about space solar power for quite some time, as to how it could be more profitable than ground based solar power. From all the concepts that I have seen the main problem I always ...
5
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1answer
261 views

Is utilizing the high temperature for chemical reactions on Venus a feasible way of generating electricity?

I assume utilizing habitats floating high in the Venus atmosphere as described by Geoffrey Landis. So weight, size etc is a constraint, and we will not be operating at the surface with the crushing ...
14
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2answers
7k views

How powerful are reaction control wheels?

Most (ok, all) of my space exploration experience has been from Kerbal Space Program which has reaction control wheels with greatly exaggerated performance. I'm aware of real life missions (notably ...
6
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1answer
610 views

How much power does the Voyager radio dish draw?

I found here and here that Voyager transmits its main radio signal at 23 watts. In other words, the strength of the signal coming from its radio dish is 23 watts. However, what I want to know is how ...
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0answers
82 views

How is New Horizons powered? [duplicate]

My understanding is that New Horizons has an RTG on board, which generates electricity for it's systems. How and when was the RTG manufactured, and how does it work? How exactly does New Horizons ...
18
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2answers
12k views

What powers New Horizons?

What does New Horizons use to keep itself traveling (so far), while keeping all of its monitoring and communication systems active? I did read that it leveraged force from a gravity sling shot from ...
15
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3answers
9k views

How much RF transmit power does DSN need to send commands to Voyager?

I recently looked up how weak the Voyager signals are when they get to Earth from the 22 W transmitters (as of September 2013, it was roughly -245 dBm). But that got me wondering how many watts of ...
6
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1answer
3k views

Total Mass of the ISS Solar Array

This document does a pretty decent job of detailing the ISS solar array. There's one part, however, that is sort of ambiguous and critical to an analysis I'm performing, and so I thought I might ask ...
3
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1answer
349 views

Is the waste heat (sink) system dependent on whether the energy source is nuclear or solar?

A power plant in space causes waste heat which has to be removed from the plant. The need for large heat sinks, and their mass, kind of bogs down some of the advantages of big nuclear power in space. ...
3
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2answers
319 views

What are low-mass ways of supplying power for a 4.5kW ion thruster?

I'm in the process of designing a spacecraft for a project, and I'm at the stage of choosing the propulsion system. I'm going to use a Boeing 702 ion thruster (requiring 4.5kW) for propulsion, to ...
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2answers
3k views

Generator in space [closed]

If you spin a generator in weightless space could you generate infinite power? Of course the friction would be a issue but couldn't there be ways to reduce this in a weightless environment?
6
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1answer
444 views

Will the CST-100 recharge its batteries?

Since the CTS-100 uses lithium-ion batteries to supply its electrical power, and lithium-ion batteries self-discharge over time, will the CST-100 need to recharge its batteries at the ISS? If so how ...
3
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2answers
182 views

Is it feasible for a future Rosetta type mission to use wireless transfer of power to Philae?

While listening to the latest updates it seems like there is a limited 60 hour battery capacity left for Philae. There seems to be some information on the web on wireless power transfer using lasers. ...
5
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3answers
498 views

Could Earth's electric grid be used to power rocket launches via cable?

If our regular huge power plants on the ground could be used to power part of a rocket launch, launch mass would be smaller since fuel would not have to be carried on board. I wonder what are the main ...
9
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2answers
816 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, ...
6
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1answer
642 views

Can electricity be generated from solar storms

If a satellite covered with a thick layer of copper, were to go straight through a solar storm in the opposing direction, would the satellite produce electricity, provided the copper(or other suitable ...
6
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1answer
594 views

Could a solar thermopile be enough to power a small satellite?

It seems that a nuclear thermoelectric generator was used to power spacecrafts for some exploration missions. Can a thermopile that harvest the light/shade temperature difference on Earth's orbit be ...
13
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1answer
836 views

Are the power systems on the US and Russian segments of the ISS similar/compatible?

Clearly there is some method of power transfer between the US Segment with the honking big arrays, to the Russian segment. But since the Russian segment is basically Mir 2 (Zvezda, and an FGB tug ...
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1answer
244 views

Send a wind turbine to space [closed]

Would it be viable to send a wind turbine which will be propelled by wind during a lift to space? Will it be able to produce significant amount of electricity while in space?
32
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3answers
34k views

How much power would a spacecraft's magnetic shield require?

I've read over the decades that a magnetic shield might protect a spacecraft from cosmic radiation. Its a fascinating idea that might only be theory or science fiction at the moment. In regards to ...
9
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3answers
6k 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 ...
6
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2answers
1k views

Do exercise machines on the ISS generate electric energy?

I'm just curious, do exercise machines for weight lifting and cycling have electric generators built in them to charge International Space Station batteries, or it's all going to waste?
12
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1answer
777 views

Can the Van Allen radiation belts serve any useful functions for space flight?

Most discussions of the Van Allen radiation belts focus on the necessity to shield sensitive electronics and biomass from radiation hazards. But are there any possible uses for this cache of highly ...