Questions tagged [power]

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

Filter by
Sorted by
Tagged with
35
votes
3answers
37k 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 ...
28
votes
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 ...
27
votes
3answers
3k 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
votes
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 ...
9
votes
1answer
1k 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
votes
2answers
347 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 "...
16
votes
3answers
10k 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 ...
4
votes
1answer
263 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 ...
54
votes
4answers
7k 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
votes
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
votes
2answers
718 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 ...
7
votes
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?
4
votes
1answer
284 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 ...
1
vote
1answer
2k 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 ...
9
votes
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
vote
1answer
183 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 ...
13
votes
5answers
7k 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
votes
1answer
2k 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
votes
1answer
2k 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 ...
13
votes
1answer
911 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 ...
10
votes
1answer
564 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 ...
7
votes
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 ...
2
votes
0answers
68 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 ...
17
votes
3answers
5k 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 ...
12
votes
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
votes
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 ...
5
votes
1answer
276 views

How are the Curiosity rover's batteries doing after all these years (and all these cycles)? 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 ...
2
votes
0answers
300 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) ...
2
votes
0answers
77 views

Mass of a circumlunar power transmission line?

The most easily available power source on the Moon is solar power. This has the obvious drawback that the night is two weeks long, during which you would probably still need power for a base to ...
1
vote
0answers
94 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), ...
1
vote
1answer
92 views

Which fuel cell fuels have been demonstrated in space?

Combination of fuel cells and electric motors - whether it has been used as part of an electric pump-fed cycles? gives a short summary of fuel cells and lists the following energy-containing fuels ...
15
votes
2answers
521 views

How did the Mir crew recover from the power outage following collision with Progress 34?

There are several accounts about how and why the collision between Mir and Progress 34 happened and that it ended in Mir being completely dark and silent: "'For the first time I experienced a ...
9
votes
9answers
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 ...
2
votes
2answers
288 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 ...
14
votes
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? ...
14
votes
1answer
992 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?
4
votes
2answers
9k 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 ...
3
votes
2answers
600 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 ...
3
votes
2answers
141 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 ...
19
votes
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
votes
2answers
1k views

How do space missions preserve their batteries for so long?

If I have a set of rechargeable batteries, I count myself lucky if I can get them to last for more than 2 years. Yet there are many spacecraft out there, which use their batteries much more regularly ...
8
votes
4answers
935 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
2answers
148 views

Are power nuclear reactors (including advanced designs) really vastly less “aggressive” in design than NTR cores?

It is my understanding that solid-core nuclear thermal rocket reactors are extremely aggressive designs that operate at the limits of materials and have an incredibly high specific thermal power. Do ...
3
votes
1answer
228 views

How many “main” batteries does the ISS have? How many are still nickel-hydrogen?

CBS News's Third all-female spacewalk completes job of swapping out batteries says: NASA is in the process of replacing 48 older-generation nickel-hydrogen batteries in the station's solar power ...
2
votes
1answer
276 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, ...
1
vote
2answers
165 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. ...
1
vote
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 ...