Questions tagged [heat]

Questions about issues related to heat and temperature, and situations where heat (too much or too little) is the primary issue. Examples include heat management in spacecraft and heat used for power generation using the flow of thermal energy from a source to a sink.

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Would Starship do a direct descent into the atmosphere and aerobrake or do a capture burn before aero braking

Due to re-entry heating and the sheer velocity when coming in from solar orbit into the Earth's SOI, will Starship do a capture burn to slow it down before entering the atmosphere or just go for a ...
Lawn Hollander Lawn's user avatar
5 votes
4 answers
6k views

Why does the heatshield have to be on the outside?

To what extent has internal insulation been tested to deal with the heat of re-entry? In the case of Starship, is the existing steel strong enough (to be non-ablative!), or would a different type of ...
Dagelf's user avatar
  • 517
18 votes
2 answers
1k views

What kind of heating would occur during a suborbital re-entry?

What kinds of peak temperatures would a stage similar in proportions to the Space shuttle with a similar belly-first approach experience when re-entering from a low suborbital trajectory (similar to a ...
XBN's user avatar
  • 189
0 votes
1 answer
117 views

Does an inflatable heat shield have some capacity to be used for LEO Earth's atmospheric entry?

It was originally designed and tested by NASA for Mars missions. In my case, it does not have to work 100%. Even if it survives for only 1 minute or so, during atmospheric entry - it could add some ...
TheMatrix Equation-balance's user avatar
2 votes
0 answers
134 views

How to get the reduction in Heat Flux due to Barbecue Roll on Spacecraft?

As we know, to keep the surface of the spacecraft relatively cool, we spin the spacecraft so that not just one side of the spacecraft is heated. Due to this what is the effective Heat Flux encountered ...
Taha Merchant's user avatar
28 votes
2 answers
5k views

Why do the walls of a solid rocket booster not glow red hot?

After ignition the walls of the SRB are separated from the "reaction chamber" by solid rocket fuel. But as the burn progresses, more and more fuel is used up and so the isolation from the ...
TrySCE2AUX's user avatar
  • 3,255
3 votes
0 answers
87 views

Cold-tolerant Mars electronics

For humans Mars isn't cold: there is little atmosphere to remove the waste heat from metabolism and life support equipment. But for electronics lacking an RTG, heat loss is a problem. Ingenuity, being ...
Kevin Kostlan's user avatar
0 votes
2 answers
248 views

Could a Stirling engine be used to produce more electricity in space?

A Stirling engine (https://en.wikipedia.org/wiki/Stirling_engine) is an engine which uses temperature differences to turn. In space it is hard to conduct heat so very often the sunny side of an object ...
The Rocket fan's user avatar
4 votes
2 answers
189 views

Why does the hot side of the JWST seem so much hotter than any other satellite?

The JWST has a hot side of 125$^\circ$C, according to NASA. Is it the only space vessel to get that hot? This site talks about many aspects concerning the temperature of satellites, but none of them ...
jAMES DONAGHY's user avatar
0 votes
0 answers
127 views

What are the Specific heat ratios of fluorine, Isopropyl Alcohol and Uranium?

I needed to calculate thrust and velocities of a rocket engine and its exhaust and in order to do that, I needed the values of Specific heat ratio(k) of Fluorine and k of Uranium and Isopropyl Alcohol....
TheNerdium's user avatar
4 votes
2 answers
140 views

JWST detector heat load

A lot of information has been published about shielding the JWST from solar radiation and the need to maintain the detectors at a low temperature, but little has been said about the other sources of ...
James Pruett's user avatar
3 votes
1 answer
126 views

Long lived solar powered rovers without radioisotope heater units (like Zhurong), for use beyond Mars

The Yutu rovers use RHUs to stay warm and survive the two week long lunar nights, every other rover uses nuclear material as well (except Sojourner), but the Zhurong rover uses a novel storage-heating ...
we'll see's user avatar
  • 477
9 votes
1 answer
746 views

How hot do the nose cones of fairings actually get on ascent?

I've been reading into aerodynamic heating of rockets, and it's seemingly a rather complicated topic. It's relatively easy to calculate the stagnation temperature at a given mach number, and that is ...
DodoDude700's user avatar
5 votes
2 answers
514 views

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. ...
Auberron's user avatar
  • 1,506
3 votes
1 answer
504 views

Conversion of heat into electricity in rocket nozzles

Can we use advanced thermoelectric materials to reduce the temperature of nozzles by converting heat energy to electric energy and reducing the strain on the nozzle material and the coolant while ...
cntcod3's user avatar
  • 69
5 votes
3 answers
922 views

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 ...
DrZ214's user avatar
  • 4,566
5 votes
1 answer
2k views

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 ...
dlight's user avatar
  • 243
14 votes
2 answers
367 views

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 ...
uhoh's user avatar
  • 149k
7 votes
1 answer
495 views

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 ...
loopbackbee's user avatar
3 votes
3 answers
1k views

Would it be possible to avoid the heat-from-friction problem when re-entering the atmosphere by performing (vertical) "U-turns"?

If you lift a swing at a children's playground and release it will swing back and forth for a while, losing some altitude in each swing, mostly (?) due to drag. Eventually it has lost all energy and ...
d-b's user avatar
  • 291
1 vote
0 answers
69 views

Do black holes emit enough heat to heat a planet? [closed]

Under what circumstances can a blackhole emit enough heat to allow life on an orbiting planet?
user38772's user avatar
6 votes
1 answer
192 views

Starship surface heating on Mars landing

Mars atmosphere is much thiner than Earth's And then how much will Starship heat on a Mars landing comparing to a landing on Earth?
Joe Jobs's user avatar
  • 2,630
1 vote
0 answers
25 views

How do you balance speed and exposure time when trying to reduce heating? [duplicate]

I'm trying to understand how you choose your acceleration/deceleration and trajectory during launch and reentry to minimize aerodynamic heating.* Ignoring efficiency in terms of delta-v (best leave ...
TheEnvironmentalist's user avatar
16 votes
2 answers
4k views

How hot do rocket engine nozzles get?

What temperatures are encountered by the nozzles of rocket engines like those in SpaceX's Merlin series? Radiative or regenerative cooling, atmosphere or vacuum. There's plenty of info about exhaust ...
Camille Goudeseune's user avatar
3 votes
2 answers
398 views

How to determine heat transfer for survival on Venus?

I'm trying to determine how long a probe could survive on Venus' surface. Assuming its just a sphere of titanium with room temperature air inside, what would be the best method for determining the ...
Halen's user avatar
  • 39
2 votes
1 answer
238 views

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 ...
Peter Nazarenko's user avatar
6 votes
2 answers
282 views

How deep into the corona could the Parker Solar Probe go without being damaged?

An answer to the question Has any object launched from Earth gone into the Sun? says The probe will repeatedly touch the outer corona until mission end in 2025, with the closest approach being 3.83 ...
Bob516's user avatar
  • 6,927
9 votes
2 answers
1k views

How do space blankets (thermal blankets) work?

On earth, blankets serve to primarily buffer temperature changes / heat transfer that would occur via convection (e.g. a blanket traps air near you so that after your body warms it, it doesn't just ...
Kasper Kubica's user avatar
1 vote
0 answers
36 views

What are the methods of heat transfer on a tubular heat pipe and how is its thermal circuit?

I would like to know how many heat transfer methods are on a tubular heat pipe and the configuration of its thermal circuit.
Beto's user avatar
  • 11
2 votes
1 answer
81 views

How much heat is reabsorbed by a high-speed object?

I have been playing around with an app to demonstrate high speed objects entering earth's atmosphere. I am using the drag equation to approximate how much kinetic energy gets converted into heat at ...
RBarryYoung's user avatar
2 votes
1 answer
344 views

Which theory does this reentry heating rate equation come from?

The paper by Wang et al. at Scitech 2018 uses the following constraint on the rocket heating rate (equation (3) in the paper): $$k_Q \sqrt{\rho} V^{3.15} \le \dot{Q}_{max}$$ (screen shot) I am ...
space_voyager's user avatar
-5 votes
1 answer
172 views

How to heat up the inside of a metal ball in space

Ok, they say third times the charm. Say you had a metal ball around 30 feet in diameter. At a distance of 143 million miles from the sun and you were trying to heat the air up inside the ball using ...
tajs's user avatar
  • 67
5 votes
0 answers
75 views

Understanding the basics of spacecraft thermal control systems

I have a broad understanding that in spacecraft cooling systems where a circulating liquid is used, a first coolant usually runs through the spacecraft and collects heat and then passes through a heat ...
James Bond's user avatar
5 votes
0 answers
178 views

Design considerations for a space suit going to Mars?

Essentially, I am trying to design a heat exchanger for a space suit traveling to mars. From my understanding, I assumed that the energy generated from the space suit relates to the astronaut as well ...
Rye's user avatar
  • 51
3 votes
1 answer
362 views

How do Stirling radioisotope generators maintain a temperature differential in a vacuum?

I was reading the wikipedia page on RTGs and happened to stumble upon the section about efficiency. There were three methods that seemed to rely on direct conversion of thermal energy into electrical ...
Magic Octopus Urn's user avatar
8 votes
1 answer
1k views

Why is the Heat Shield of ESA's Solar Orbiter Black in colour?

Solar Orbiter (SolO) is a planned Sun-observing satellite, under development by the European Space Agency (ESA). Due to its proximity to the Sun, it receives about 13 times more solar energy than we ...
Vishnu's user avatar
  • 3,276
2 votes
0 answers
100 views

Minimal heating a realistic reentry vehicle could achieve?

In this question, I asked whether it would be possible to make a reentry vehicle that could slow down from orbit and glide to the ground entirely passively. The answers and comments point out several ...
Eth's user avatar
  • 769
2 votes
0 answers
43 views

At the same temperature, what's the relation of speed of heat loss between Earth and Mars?

Mars has a thinner athmosphere than Earth. Let's say you have a similar shelter of the same volume and made of the same materials in Mars at -70 Celsius, and in Earth in some place in the Antarctica ...
Pablo's user avatar
  • 885
4 votes
1 answer
795 views

Why don't the hottest temperatures of a re-entering spacecraft occur near the "bottom"?

The paintings of the Apollo command module and space shuttle below portray the heating effects of re-entry. The whitest parts of the spacecraft get the hottest, with cooler parts in red and darker ...
DrSheldon's user avatar
  • 48k
3 votes
0 answers
160 views

How large of a mirror would be needed to warm Titan up?

How large of a mirror would be needed to warm Titan up to ~290K? Paul Birch in his paper "Terroforming Mars Quickly" calculated a mirror size of: Support Mirror: 2.5 x 10^7m radius 3x 105m wide ...
Pepe Cossio's user avatar
5 votes
1 answer
187 views

Maximum speed based on atmospheric altitude given maximum temp?

I saw the question Could escape velocity be achieved in the atmosphere? and thought it probably could've been asked better. I'm sure there's an equation to calculate the average heat generated by an ...
Magic Octopus Urn's user avatar
23 votes
2 answers
4k views

Why not increase contact surface when reentering the atmosphere?

If a craft were to increase the surface area where contact is made with air during reentry, I imagine the heat quantity per area unit would decrease, making the use of (heavy) heat shields less of a ...
Magix's user avatar
  • 605
3 votes
1 answer
477 views

Launch pads flame deflectors

I was interested in knowing if all launch pads possess a flame deflector. I'm inclined to say yes, as the structure seems vital for a safe launch. Wanted to make sure, though, if there could be a case ...
Jak's user avatar
  • 387
2 votes
1 answer
140 views

Heat balance of the ISS: breakdown?

Is there available breakdown of the heat balance of the International Space Station? In particular: How much heat is produced? by direct warming by sun by warming of solar panels (heat for the ...
Irigi's user avatar
  • 675
3 votes
1 answer
133 views

Selection criteria for coolant media on spaceships

What is the selection criteria for coolant media on spaceships? I have read that ammonia as well as water glycol have been used. These two have very diverse properties. So what makes both of them ...
Niranjan's user avatar
  • 3,758
4 votes
1 answer
126 views

Could a spacecraft produce lift using sublimating material?

Following this question, could a spacecraft approaching upper atmosphere from very low circular Earth orbit, produce lift to soar propulsively, bleeding speed at constant apoapsis, by sublimating ...
user avatar
6 votes
1 answer
257 views

How much delta-v is lost to heat of exhaust?

It occurred to me that all of the kinetic energy not going exactly in the opposite direction of a spacecraft is wasted! Since heat is essentially kinetic "noise" in objects, I wondered how much more ...
Andrew Nova's user avatar
4 votes
0 answers
74 views

Has the monthly average skin temp of the ISS increased during its years in orbit?

Is there a source of monthly average sun-side maximum temperatures during its (ISS) years in orbit?
William Bass's user avatar
7 votes
3 answers
5k views

Why is Adiabatic wall temperature taken as the driving temperature in rocket engines?

Going by the definition of convective heat transfer coefficient from Wikipedia (which I have started to doubt; reason follows): $h=\frac{q}{\Delta T}$, where the $\Delta T$ is taken as the difference ...
karthikeyan's user avatar
  • 4,469
3 votes
2 answers
1k views

Orbital reentry glider with no heat shield

Let's assume a reentry craft designed to not use heat protection like Soyuz or the Space Shuttle, and budget is not an issue. The Concorde max surface temperature was 400 K, so let's use this as a max ...
Eth's user avatar
  • 769