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Questions tagged [power]

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

53
votes
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) ...
28
votes
3answers
26k 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 ...
26
votes
3answers
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
votes
1answer
1k views

How long will communication with the Voyager probes continue?

Voyager 1 and 2 are the most distant man made objects. How long will we be able to still communicate with them? What will be the first thing that prevents communication? RTG exhaustion? Signal ...
17
votes
2answers
11k 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 ...
17
votes
1answer
729 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
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 ...
16
votes
2answers
519 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 ...
15
votes
3answers
7k 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 ...
15
votes
1answer
1k 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 ...
14
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 ...
13
votes
1answer
967 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 ...
12
votes
2answers
5k 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 ...
12
votes
1answer
687 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 ...
12
votes
1answer
765 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?
12
votes
1answer
402 views

What is the typical power redundancy built into a spacecraft?

NASA's Juno page says The Juno spacecraft launched aboard an Atlas V-551 rocket from Cape Canaveral, Fla., on Aug. 5, 2011, and will reach Jupiter in July 2016. The spacecraft will orbit Jupiter 32 ...
12
votes
1answer
815 views

Is there an alternative to nuclear reactors for high-power spacecraft?

Many of my favorite ideas for space exploration, such as large outer solar system probes, or the Mars Direct human Mars exploration proposal, require nuclear reactors to supply the high-power ...
12
votes
1answer
644 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 ...
11
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 ...
11
votes
5answers
4k 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 ...
11
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 ...
10
votes
2answers
215 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
7answers
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 ...
9
votes
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
votes
2answers
263 views

Could electricity propel Curiosity on Venus?

To-date the humans have dispatched surface missions to Mars Luna Venus Mars has a thin atmosphere. Luna lacks one. Venus has a soup-thick atmosphere. Landing a static craft on Venus is one thing. ...
9
votes
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
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 ...
9
votes
1answer
385 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) ...
8
votes
4answers
718 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 ...
8
votes
3answers
243 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 ...
8
votes
3answers
794 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 (...
8
votes
1answer
404 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
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 ...
7
votes
5answers
3k views

How does a solar eclipse affect satellites?

Satellites are somewhat closer to the Moon than the Earth is (Or rather, can be), and might well have the sun blocked from them. Furthermore, they can move somewhat more than the Earth, and thus have ...
7
votes
2answers
569 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 ...
6
votes
1answer
2k 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 ...
6
votes
1answer
524 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 ...
6
votes
1answer
426 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 ...
6
votes
2answers
191 views

Using Kilopower without shielding

The KRUSTY reactor (the first actual test under the Kilopower project) is shown in this image. As can be seen, about half of the mass is shielding. Suppose we were using the reactor on an umanned ...
6
votes
1answer
530 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
votes
1answer
302 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 ...
5
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?
5
votes
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
votes
1answer
407 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 ...
5
votes
2answers
157 views

In what ways could a US-based commercial space company legally use nuclear power?

At the moment, commercial usage of space seems to be the next big 'thing' in space exploration. Much of this (tourism, commercial launch companies, etc) will likely use solar power or fuel cell ...
5
votes
1answer
429 views

What is the proper way to charge Lithium Ion batteries?

Lithium Ion Batteries are becoming more and more popular in spacecraft, due to their high power per mass ratio. There are several companies, such as Quallion, advertising their space rated batteries. ...
4
votes
1answer
4k 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
votes
4answers
132 views

Radioisotope thermoelectric generator behavior on reentry

The RTG has become a major source of power in places where solar power just wont cut it. but there has always been an issue with sending them into space. if the launch fails, radiation comes raining ...
4
votes
2answers
246 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 ...
4
votes
2answers
389 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 ...