Questions tagged [power]

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

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32
votes
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 ...
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 ...
28
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4answers
2k views

Are there any safe-to-launch alternatives to RTG's for outer solar system exploration?

In the past two decades, NASA has launched at least three missions that use RTG's: Cassini Mars Science Laboratory New Horizons Those launches include plutonium, which is a reason for some to oppose ...
25
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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 ...
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 ...
9
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1answer
778 views

Why was the ISS' DC vacuum cleaner replaced with an AC version? Are there “wall sockets” throughout the ISS where it's plugged in?

The question Why did Apollo spacecraft use both AC and DC equipment? Still used in present and future designs? and especially the answer there reminded me of something I'd seen in the YouTube video ...
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 "...
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) ...
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 ...
16
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2answers
695 views

How does the launch risk posed by plutonium compare to the launch risk posed by propellants?

For outer solar system exploration, virtually the only feasible power subsystem are Radioisotope thermoelectric generators (RTGs). These include plutonium, which may carry considerable risks (see ...
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?
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 ...
1
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1answer
150 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 ...
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 ...
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 ...
16
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1answer
1k views

What is the power requirement of a spacesuit?

A spacesuit is a fairly easily identifiable piece of equipment in spacecraft. It's purpose is to keep it's interior distinct from the exterior in terms of the pressure, and temperature differentials ...
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 ...
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 ...
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 ...
9
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2answers
4k views

What power source options provide reliable and sustainable power generation for a Martian Colony

In order to maintain a Colony on Mars, we will need to be able to provide consistent, safe, and sustainable power on the planet. The extremely cold temperature means that the need to maintain ...
4
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0answers
101 views

How are Curiosity's batteries doing after all these years? Have they degraded significantly?

Curiosity has spent 2820 sols on Mars and this answer to About how long will Curiosity last on its nuclear power? points out that its batteries may wear out faster than its RTG. Question: How are ...
1
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0answers
61 views

At what incline would curiosity require twice the electrical power to drive compared to a flat grade?

Motors have losses and friction, and compaction of soil by a rovers wheels are lossy as well. Driving over bumps/topography requires extra work going up that isn't recovered when going back down. The ...
14
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1answer
2k views

How does electrical safety system work on ISS?

Is there any possibility that the power consumption is greater than power supply on ISS? What happens (or potentially would happen) if we plug too many electric devices so that ISS couldn't handle it? ...
13
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1answer
837 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 ...
13
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1answer
870 views

Could Jupiter's tidal forces be used to generate energy?

Let's say we have a colony on Europa (or any other Jovian moon really). Jupiter exerts a lot of tidal forces on its satellites. Could this force be used to generate energy for our colonists?
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 ...
4
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2answers
7k views

What is the maximum speed an ion engine can propel a spacecraft at?

I read that with our current ion propulsion technology it is possible we could send a craft moving the maximum of 100km per second, or around 62 miles. However we seem to be limited by how strong of a ...
4
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1answer
170 views

Are there fuel cells for methane + oxygen? Could there be?

Hydrogen + oxygen fuel cells powered the week-long Apollo missions to the Moon and Shuttle missions to orbit, and there is a industry trying to build itself around hydrogen-fed fuel cell-based road ...
3
votes
2answers
542 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 ...
2
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2answers
205 views

Could electricity be generated from a Martian dust storm?

This helicopter is producing static electricity from the blades moving through the dusty air. Along with the electricity provided by wind generators could additional power be created this way from ...
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 ...
12
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3answers
2k views

Why exactly does curiosity's RTG make more electricity on cold days?

There is a fascinating factoid in this answer to MMRTG- thermal and electrical output: The electric power of the thermocouples depends on cooling influenced by the environment. On a cold day on Mars ...
8
votes
4answers
894 views

Would it be practical to use the electrical charge of the Lunar surface as an energy source?

This question discusses the charges that exist on the Lunar surface. Would it be possible or practicable to use the differential between the surface and subsurface or different locations on the ...
3
votes
1answer
171 views

Does NASA really report the power of rockets in horsepower?

On a recent episode of The Late Show with Stephen Colbert, Dr. Neil deGrasse Tyson said: And to this day NASA will still report the power of rockets in horsepower, which is completely absurd, ...
3
votes
1answer
189 views

What is the current status of Stirling engine-based radioisotope generator technology?

@Heopps' cool answer to the question Any proposed missions to explore the black liquid on Titan? Technical challenges? has an interesting line: ASRG generator was planned as compact energy source ...
2
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0answers
296 views

What kind of power is referred to in “the…most powerful all-electric propulsion communications satellite ever produced”

The Florida Today article On second flight, SpaceX Falcon 9 rocket to launch 'brute' of a satellite from Cape describes the upcoming SpaceX launch of SES-12. Next to this tiny image of (presumably) ...
1
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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 ...
1
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0answers
88 views

Use or tests of multimode optical fiber for cubesat battery charging or datalink while in storage, or waiting to launch?

the idea of POF or power over fiber is to couple a moderate amount of solid state laser light, say a few hundred milliWatts or even several Watts (or potentially more, but it gets more challenging), ...