Space Shuttle Heat Transfer Question

In summary, in space, an object such as a space shuttle can only lose cabin heat through radiation. Determining the emissivity of space is a complex process, but for objects in orbit around Earth, the Earth and the Sun are treated separately. During re-entry, the heat generated is mainly from compression of the surrounding air, with convection aiding in the heat transfer. The intensity of solar radiation at the top of Earth's atmosphere is about 1500 w/m^2, while the temperature of space is around 2.4 kelvin. The emissivity of space is approximately 1.0, and the shuttle's own emissivity and surface area must also be taken into account.
  • #1
anthonyj915
1
0
From what I gathered in Heat transfer, an object in space, ie space shuttle, can only lose cabin heat through the means of radiation (no conduction or convection off the surface...) So how would one go about determining what the emissivity is in space. Obviously there will be objects that are hotter (sun) but there is a lot of nothing.

Anyone have some insight as to how to ball park that figure?

The other think i was thinking about, was on re-entry the space shuttle gets hot. What is causing this heat? I know its the friction between the air and the shuttle, but doesn't the air flowing past also aide in the Convection heat transfer?

Thanks
 
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  • #2
The ball-park figure for space itself is Zero and you treat the sun separately and since it is so much hotter than objects such as the space shuttle, you just use the solar radiation flux (340w/m^2 iirc). For an object in orbit around the earth, you'd probably treat the Earth separately as well and use the S-B equation.

For re-entry, the heat is more from the compression of the air than from friction, so since the air itself is getting hot, the convection is what heats up the shuttle.
 
  • #3
I believe the original post asks about the emissivity of space, which is probably about 1.0, and a ballpark figure for the temperature of space is about 0 (2.4 kelvin to be a little more precise). You will also need to know the emissivity of the shuttle itself, along with the surface area.
BTW, Isn't the intensity of solar radiation about 1500 w/m^2 at the top of the Earth's atmosphere?
As for heating during re-entry, even though the air molecules are traveling at a relatively slow speed (in Earth reference frame) which is consistent with them having a low temperature, from the shuttles' frame of reference, they are moving quite fast and hence have a very high temperature. In effect, the shuttle is surrounded by very hot gas and so it gets heated. Of course, the gas is mostly moving in a single direction, as compared to randomly for a "normal" hot gas.
 

1. How does heat transfer work in the space shuttle?

Heat transfer in the space shuttle is predominantly a process of convection. This means that heat is transferred through the movement of fluids, such as air or water. The shuttle's thermal protection system is designed to manage this heat transfer by using materials that are highly resistant to high temperatures.

2. What materials are used to protect the space shuttle from heat during re-entry?

The thermal protection system of the space shuttle is made up of various materials, including reinforced carbon-carbon, silica tiles, and Nomex felt insulation. These materials are chosen for their ability to withstand extreme temperatures and their lightweight properties, which are essential for space travel.

3. How does the space shuttle's heat shield work?

The heat shield of the space shuttle is made up of tiles and blankets that are designed to absorb and dissipate heat during re-entry. The tiles are made of a special type of ceramic that can withstand temperatures up to 3,000 degrees Fahrenheit. The blankets are made of layers of heat-resistant materials that trap air and prevent heat from reaching the shuttle's structure.

4. Why is heat transfer important for the space shuttle?

Heat transfer is critical for the space shuttle because it allows the shuttle to safely withstand the extreme temperatures experienced during re-entry into the Earth's atmosphere. Without proper heat transfer management, the shuttle's structure could be damaged or destroyed by the intense heat generated during this process.

5. How is heat transfer managed during space shuttle missions?

Heat transfer is managed through the use of the shuttle's thermal protection system, which includes the heat shield, as well as the positioning of the shuttle's orbit during re-entry. The shuttle also has onboard systems, such as cooling pumps and radiators, to help regulate and dissipate heat during its mission.

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