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39 votes

Could a fan be used to prevent overheating on a Venus bound space probe?

Fans work by moving cool air (or other fluid) over a warm surface. If there is no air, like in space, a fan will serve no purpose. Cooling things in space is actually a bit tricky because of this - ...
Nuclear Hoagie's user avatar
30 votes
Accepted

Are fans ever used in un-crewed spacecraft?

Soviet planetary probes sometimes had pressurized compartments, so I suspected that they might contain fans. This answer confirms that Venera-8 had a fan. The illustration in the answer has the inner ...
Organic Marble's user avatar
19 votes
Accepted

Why did the Herschel Space Telescope need helium coolant?

Imagine your telescope optics looked like this red-hot glass! Herschel's instruments look at the world in the wavelength range of 55–672 µm. When plotted as a function of wavelength, the thermal ...
uhoh's user avatar
  • 148k
17 votes
Accepted

How do satellite motors keep themselves cool and lubricated?

There is only one regular car in space, but it doesn't have a piston engine — as leftroundabout pointed out so helpfully, it is a Tesla, an electric vehicle. Even without piston engines, however, ...
Peter - Reinstate Monica's user avatar
16 votes

How do satellite motors keep themselves cool and lubricated?

Satellites never use Internal combustion engines like in cars (obviously they do have propulsion engines that require combustion for station-keeping purposes) in them, they mostly use solar-power and ...
Kavin Ishwaran's user avatar
15 votes

Are fans ever used in un-crewed spacecraft?

Sputnik-1 was filled with dry nitrogen pressurized to about 1.3 bar and had a fan to control gas temperature between 20° and 30° C. See Wikipedia in german or english. A picture of Sputnik-1 design ...
Uwe's user avatar
  • 48.8k
14 votes
Accepted

Could Stirling Engines work on sunlight alone?

Could Stirling Engines work on sunlight alone? With the heated side facing the sun and the rest in its own shade, could two contra-rotating Vacuum Stirling Engines and flywheels, in tandem, accumulate ...
uhoh's user avatar
  • 148k
13 votes
Accepted

Concerns/challenges with LOX as a regenerative coolant

To answer your first question: one of the main problems with using the oxidizer in general is oxidizing of the cooling channels. Any hot oxidizer has this problem, but oxygen definitively has this ...
Ruben's user avatar
  • 1,064
13 votes
Accepted

Using coolant as 3rd propellant

Early liquid fuel rockets kinda did this, by adding water to the fuel (V2: 75% ethanol, 25% water). Another related example is the Viking engine, which uses water to cool combustion gases entering the ...
SE - stop firing the good guys's user avatar
13 votes

Why did the Herschel Space Telescope need helium coolant?

Herschel was an infrared space telescope. According to this paper, the performance is expected to be not far from background-noise limited, with sensitivities (5σ in 1h) of ∼ 4 mJy or 3 − 20 × $10^...
DrSheldon's user avatar
  • 47.8k
13 votes
Accepted

Why does the Alpha Magnetic Spectrometer (AMS) on the ISS use carbon dioxide for coolant?

1) There is no superconducting magnet in AMS-2. This would have required cooling with liquid helium resulting in a limited life time of only 3 years because of helium evaporating. Instead, they used a ...
asdfex's user avatar
  • 14.9k
13 votes

How do satellite motors keep themselves cool and lubricated?

There are a few elements here that are worth considering. Part of the story is to do with the purpose of the engines you might find in a satellite, or space vehicle for that matter. While the other ...
Andrew Micallef's user avatar
11 votes

How do satellite motors keep themselves cool and lubricated?

For a satellite you need something that functions in zero gravity for many years without any maintenance or repair. Therefore piston engines are not used. To produce electrical energy solar cells are ...
Uwe's user avatar
  • 48.8k
10 votes

Could a fan be used to prevent overheating on a Venus bound space probe?

The effect of a fan in an electronic device is to accelerate the temperature exchange between circuits and atmosphere. But that temperature exchange works in both directions. When the atmosphere is ...
Philipp's user avatar
  • 9,346
9 votes

Why does ISS uses liquid ammonia in the Active Thermal Control System?

Ammonia is used because it has excellent heat transfer properties (as you mention) and a low freezing point. Because of its toxicity, the ISS has internal coolant loops which use water as a heat ...
Organic Marble's user avatar
9 votes
Accepted

How were Apollo spacesuits cooled during simulations/rehearsals on Earth?

Nearly all Earth training was performed in the A6L model spacesuit (seen in the pictures above). Actual missions flew with the A7L model suit. Differences include: The outer (EVA) layer of the A6L ...
DrSheldon's user avatar
  • 47.8k
7 votes

How do satellite motors keep themselves cool and lubricated?

The requirements on engines (really motors in my experience) in space are very different from the requirements on automobile engines on the ground. This leads to very different designs and very ...
Ross Millikan's user avatar
6 votes
Accepted

How much could "sublimator operation" have possibly contributed to Apollo 11's "sizable downrange miss"?

Frank O'Brien in his book "The Apollo Guidance Computer: Architecture and Operation", on p. 229 concludes that effect from sublimator vapour thrusting could've been measurable: A quite real source [...
Sergiy Lenzion's user avatar
5 votes

How do pressure-fed engines stay cool?

The space shuttle's Orbital Maneuvering Engines (OMEs) were pressure-fed hypergolic engines burning nitrogen tetroxide and mono-methyl hydrazine. The combustion chamber was regeneratively cooled by ...
Organic Marble's user avatar
5 votes

How do pressure-fed engines stay cool?

Regenerative cooling can be done with pressure-fed rockets just as it is with pump-fed rockets, the only differences are the source of the pressure driving the fuel (and sometimes oxidizer) through ...
Christopher James Huff's user avatar
5 votes

what is the temperature of solar panels used in space missions such as ISS

Unfortunately telemetry readings aren't shown on ISSLive.com (Tristan has actually pointed out to me there is no telemetry, which to me is a surprise, but there you go). See this analysis for the ISS. ...
Puffin's user avatar
  • 9,434
5 votes

Why does the Alpha Magnetic Spectrometer (AMS) on the ISS use carbon dioxide for coolant?

Supplementary answer to this excellent one because a) I like schematics, and b) downloaded a bunch of info a while back in anticipation of AMS EVA questions that haven't yet been asked. The cooling ...
Organic Marble's user avatar
4 votes

Why do many ablative nozzles use phenolic resin and not some other resin?

For an ablative nozzle one wants the right mix of properties: low thermal conduction, high strength, and a burn (regression) rate that produces enough gas to provide effective film cooling but not too ...
Terrance Yee's user avatar
  • 2,264
4 votes

What is the feasibility of a graphite chamber, nozzle and bell walls

The ablation of high-purity graphite in oxygen and air atmospheres was studied in the 1000–1400°C temperature range,Very fast ablation rates were observed. The concern is the graphite wouldn't ablate ...
LazyReader's user avatar
4 votes

Cooling the nozzle extension of a nuclear salt water rocket (NSWR)

From one of Zubrin's own papers on the subject, NUCLEAR SALT WATER ROCKETS: HIGH THRUST AT 10,000 SEC ISP: a layer of pure water would be sprayed around the perimeter of the column to form a ...
Starfish Prime's user avatar
4 votes

How do satellite motors keep themselves cool and lubricated?

For extreme cold conditions like the WEBB telescope, most lubrication is provided by dry film lubricants since any oil would freeze solid.
BradV's user avatar
  • 3,042
4 votes

Is JWST's weak link the Cryocooler for the MIRI instrument?

JWST's weakest link is the propellant needed to maintain its pseudo-orbit about the Sun-Earth L2 point and to desaturate the vehicle's momentum wheels. That propellant will eventually run out. ...
David Hammen's user avatar
  • 73.2k
4 votes
Accepted

Estimations for Gas-Side Wall Temperature Within Rocket Engines

It's definitely not clear or stated explicitly, but I think that the 1500 deg R is a design goal, i.e. the cooling for the chamber will be designed such that the wall temp doesn't exceed approximately ...
Organic Marble's user avatar
3 votes

Decomposing HTP through regenerative cooling for use in closed expander cycle

I think the main concern is the explosive characteristics of H2O2 vapor. If you go through some literature, You would find that the vapor of more than 26-mole percent of H2O2 is likely to face an ...
PROSCO's user avatar
  • 31

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