Questions tagged [thermal-control]

Questions about heat management in spacecraft

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How can you calculate the pressure that a liquid develops when freezing in a pipe?

My current understanding is that in addition to the reasons pointed out in the answer to this question here, another reason for choosing ammonia in the space station external coolant loops is that the ...
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Alodine on Spacecraft External Surfaces?

What type of alodine is used for external coatings on satellites, if necessary? Is it type 1 (hex chromate) or type 2? Is there a disadvantage using type 1?
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Why is the sunny side of JWST's sunshield purple and covered with silicon?

After about 08:52 in Destin's Smarter Every Day's Why Are there Holes in the James Webb Sunshield? (Explained by My Dad) - Smarter Every Day 270 (linked below) ...
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First use of spacecraft thermal control louvers, doors, pinwheels, or other things that physically actuate either passively or actively?

Below are some examples of Question: What was the first use of spacecraft thermal control louvers, doors, pinwheels, or other things that physically actuate either passively or actively? From this ...
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The temperature displayed online for Webb has not changed even one degree in days, even though the sunshield deployed in that time. Why? [closed]

First exposed, then shaded by sunshield, no change in displayed temperature, how can this be correct? As soon as I posted, they updated the temps. I have watched this for days before this and no ...
4 votes
2 answers
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How long can astronauts wearing Dragon capsule suits walk around unconnected to water coolers?

At various moments in the NASA video NASA’s SpaceX Crew-3 Astronauts Launch to the Space Station astronauts are shown standing or walking or otherwise posing for the camera in their Dragon capsule ...
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JWST -- thermal control predictions

JWST app "where is webb" just started displaying vehicle temperatures. It is said in the background info that these temperatures were predicted from thermal modeling. I would like to know ...
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Why does JWST need "a carefully designed series of oscillations" to avoid overheating during the 2nd stage burn? Why not rotate "rotisserie style"?

The Northrop Grumman video James Webb Space Telescope Launch and Deployment describes the trajectory from launch to orbital insertion and illustrates several key maneuvers and incremental steps in the ...
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Thermal batteries rather than battery-powered heaters for small craft on Mars; how much mass would it add, how much would it replace?

As an example, the Ingenuity helicopter on Mars charges its batteries each sunny day (which is every day except when it isn't) and discharges them substantially each cold night (which is all of them) ...
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Just how preferable are afternoons for flying Ingenuity? Why?

JPL tweet links to mars.nasa.gov's Flying on Mars Is Getting Harder and Harder which explains that seasonal changes are lowering the density of the local atmosphere, presumably due to warmer seasonal ...
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Where exactly are the Apollo space suit sublimators venting steam into space? is there a photo of an astronaut in space that shows the opening?

This excellent answer to How have space suits dissipated the heat removed from astronauts? shows a diagram including the sublimator unit in the red square where the phase transition of water from ...
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Why aluminum is added in Multi Layer Insulation?

Aluminum is a highly conductive material. Instead of insulating the system from heat, it conducts. Multi-Layer Insulation aims to protect spacecraft from extreme heat by acting as a thermal barrier. ...
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3 answers
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How does a radiator work fast enough on a space craft?

Basically, after some heat exchanger, a fluid is pumped to a radiator and then releases its heat to the void of space. But I'm having a hard time seeing how that is done fast enough. The fluid should ...
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2 answers
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How much electrical energy is required to dissipate heat?

I'm modeling the electrical energy consumption of a chemical reactor for the Moon base. The reaction taking place in this reactor is highly exothermic, and the device must be cooled. My question is ...
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Why does ISS uses liquid ammonia in the Active Thermal Control System?

I saw this today and it made me very curious. See page 8 here: https://www.nasa.gov/pdf/167129main_Systems.pdf Ammonia has a boiling point of -30 C. The ammonia is liquid in these loops, so if ever ...
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Ablative heat shield and conservation of energy, how much does ablated matter in fact "carry away" versus re-radiate the absorbed heat?

I saw Most heat shields ablate, that is they sacrifice material to carry heat away... in a comment under this answer and started writing: I think that shields ablate to produce a layer of complex ...
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What kind of insulation is used in the Ingenuity helicopter?

A press release from NASA today states “This is the first time that Ingenuity has been on its own on the surface of Mars,” said MiMi Aung, Ingenuity project manager at NASA’s Jet Propulsion ...
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How are the electronic circuits in interplanetary missions protected from extremely low temperatures?

In an interplanetary mission, a spaceship travels through deep space, where the temperature is almost zero degrees Kelvin, and it is likely that its electronic circuits get permanently damaged. How ...
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How cold do Curiosity's & Perseverance's appendages get at night with all those sensitive cameras and lasers?

cropped from PIA19920: Curiosity Self-Portrait at 'Big Sky' Drilling Site MastCam-Z, ChemCam/SuperCam and MAHLI are optical systems and ChemCam includes a telescope and a pulsed laser, but the ...
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Are there fluid disconnects that sever just before the Curiosity or Perseverance rovers separate from their cruise stages or landers?

In this comment under an answer to Heating Perseverance components prior to deployment I wrote: I think (but can not find a source yet) that there is even a loop of "hot water plumbing" ...
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Likely explanation for the bottom of the SLS rocket being covered with reflective silver "muffler" tape?

NASA.gov's First Artemis Rocket Stage Moved onto NASA Barge Ahead of Green Run contains a high resolution image of the rocket. The bottom end of the rocket's cylindrical shape is closed flat and ...
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Why are some rockets painted black? [duplicate]

Why are Rocket Lab's and other rockets painted Black? Shouldn't they be painted white to reflect most light and therefore absorb less heat from sunlight?
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How did the Space telescopes lose their coolant helium?

How did the Planck satellite lose its helium? Spitzer, Herschel had the same problem. How was it consumed? How come other satellites, like Hubble, don't have this problem? And basic logic says that ...
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10 votes
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Vacuum tube microchips for Venus probe; feasibility and challenges?

Venus surface temperature is around 460 °C which makes conventional semiconductors useless. So nasa proposed a clockwork rover, drawing power from wind and using springs and gears to navigate the ...
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1 answer
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In what conditions are the electronics of New Horizons housed?

In one of answers to the question What are the long term effects of Space Weathering on man-made materials? there is a link to Wikipedia article about Kapton. In this article mentioned that NASA's ...
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Could Ingenuity stay warmer at night by landing on (or near) Perseverance's RTG?

One concern in How long could the Mars helicopter Ingenuity keep up with the Perseverance rover if it wanted to? is that the helicopter must cycle its battery every night to stay warm, and that could ...
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Now that Perseverance is "hot" (RTG in place) and before it gets to deep space, how will it stay cool?

As soon as they are assembled MMRTGs continuously produce about 2,000 watts of heat energy. That dips only slightly when they are connected to a load and producing electrical power (about 125 watts ...
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1 answer
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Why would the Falcon 9 Block 5 carbon fiber thermal protection material need to be hydrophobic?

This answer to Nature of “the silky black 'highly flame-resistant felt'” on Block 5 Falcon 9's, and its intended functions? contains the following: This came into Falcon 9 design with Block 5 ...
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3 votes
1 answer
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Are there any uncrewed spacecraft that maintain(ed) an atmosphere?

In How do phonesats stay cool? I wonder if phonesats might have had "cabin pressure" to keep the phones from overheating since they are not designed for space. But now I'm just wondering if ...
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How do phonesats stay cool?

To the question Can a smart phone function in space? this answer says Multiple android based phone satellites have been launched into space. (At least six according to Wikipedia). I haven't looked ...
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Thermal management of manned craft at Ceres

I would like help in designing a manned craft for exploration and mining activities on Ceres. The sunlight reaching Ceres is approx 10% of that in LEO. Does this mean the spacecraft would have ...
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Why do many RTGs have finned heatsinks, when this is considered bad for radiation heat transfer?

Related: Finned heatsinks in space Multi-fin heatsinks are not normally considered good for heat dissipation in space because adjacent fins radiate into each other, and you would be better off with ...
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Is heat transfer in space through radiation 100% efficient? [closed]

Flat 1x1 meter plate. Heat source indicated by red arrow. The rest is in space. No sun exposure at all. Some of the photons will exit through the gaps between plates. No problem. My question is ...
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Why put chromium on the back side of this JPL-designed solar sail?

This 2013 JPL presentation Solar System Escape Architecture for Revolutionary Science March 2013 Conference NIAC Phase 1: 2012-2013 by PI: Jeff Nosanov Co-Is: Dr. Daniel Grebow, Dr. Brian Trease, John ...
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Finned heatsinks in space

Most heat radiators in space are flat surfaces. In a sense they are single fin radiators. Has anyone studied the used of multi-finned radiators in space (the vacuum of space, not inside a spacecraft)?...
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Is thermal soakback from the engine a problem for rocket stages? Especially ones that complete several burns over several hours (e.g. S-IVB, Centaur)?

Thermal soakback is a phenomenon whereby a hot, operating engine transfers heat into the spacecraft, usually conduction through the engine mounts. I've only ever seen this problem discussed with RCS ...
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24 votes
1 answer
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Did Apollo 13 "barbecue roll" under the propulsion of the lunar module?

Apollo spacecraft were often put in a "barbecue roll" (officially called passive thermal control mode), which slowly rotated the spacecraft along its main axis. Without this maneuver, one side of the ...
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How to calculate the lowest possible altitude a satellite can orbit at due to aerodynamic heating if provided with a sufficient propulsion system?

If a satellite is equipped with a propulsion system which is enough for compensating the local drag and maintaining the orbit, then aerodynamic heating would be the limiting factor for attaining the ...
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Are black and white stripes any better than uniform gray for thermal control?

Q: What color is a spaceship? Several answers and comments on Why were Europe's first few satellites so stylish? Why the pronounced alternating white and black stripes? contain phrases like "...
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Are fans ever used in un-crewed spacecraft?

The question For a Venus bound space probe could could a fan be used to prevent overheating? got me thinking. Most if not all crewed spacecraft have had fans to move air for one reason or another. ...
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Could a fan be used to prevent overheating on a Venus bound space probe?

I saw something saying that the circuits on a Venus bound space craft would overheat and basically ruin the the spacecraft. Is that true? If so, could they install fans to keep the circuits cool?
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Why does the Alpha Magnetic Spectrometer (AMS) on the ISS use carbon dioxide for coolant?

Spaceflight Now's Astronauts finish repairs to space station cosmic ray detector says: Originally designed to operate for just three years, the AMS chalked up eight years of operation before being ...
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How are coatings like Vantablack and Aeroglaze Z306 used on spacecraft components? Exactly what functionalities do they provide?

Business Insider's SpaceX is launching 'dark satellites' to stop its Starlink project from wreaking havoc with astronomical research. Astronomers are skeptical. includes the following passage: "...
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Apollo PTC roll orientation and communication with earth

I have a 2 part question. With the Sun, Earth and Moon on the same plane, I do not understand the difference in heat distribution between perpendicular or parallel orientation with reference to the ...
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Is it feasible to paint SpaceX Starlink satellites black so as not to frequently saturate the CCDs of the Large Synoptic Survey Telescope?

update: From Nature.com News article: SpaceX launch highlights threat to astronomy from ‘megaconstellations’: But an upcoming, cutting-edge telescope could be in bigger trouble. The US Large Synoptic ...
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Why do the ISS' Thermal Rotary Radiators need to tilt?

This answer shows the first image below of a vintage view of the ISS. Only one of each triplet of thermal radiators is extended from each TRRJ. The ISS' solar panels articulate to modulate the ...
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Is it bad if hydrazine freezes on a spacecraft? Is it always kept as liquid, or can it be safely allowed to freeze and then thawed when needed?

After having read this answer I wondered what happens if hydrazine freezes. It looks like it is "normal" and not like water, in the sense that it contracts when freezing, unlike water which expands ...
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What was NASA's “LUROVA” Operational Thermal Computer Model analog or digital? How were capacitors used?

@GremlinWrangler's answer links to Apollo Rover Lessons Learned Applying Experiences on the Apollo Lunar Rover Project to Rovers for Future Space Exploration by Ronald A. Creel, Space and Thermal ...
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Is it undesirable for LOx to splash on the walls of combustion chamber?

Typically, there are annular ports on the injector plate to introduce fuel to cool the combustion chamber. Why is LOx not used for cooling despite it being extremely cold? Given there will be a lot ...
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Can an air conditioner be made to work with 0 gravity?

In another question: How does the freon compressor work at 0 gravity? This seems overly complicated to get some cold air in space. Can an A/C compressor (we use in our house) be made to have gravity ...
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