Tungsten Carbide to replace Ceramic Tiles (heat shielding)

[ortemus74]

The shuttle faces re-entry temperatures upwards to 3000 degrees Fahrenheit... Steel starts to melt at this temperature but not tungsten ortherwise known as Wolfram. Element 74 on the periodic table of elements it has the highest melting point of all metals known to man it starts to melt at around 6165 degrees Fahrenheit. This is why I suggest using Wolfram or Tungsten to shield the underbellies of future spacecraft.<br /><br />Also the metal is very dense (hard) and is among the best of cutting tools used in machine shops to craft steel... This would make perfect armor for protecting against flying debris in space. <br /><br />Tungsten Melting Point: 3680K 3407°C 6165°F

 

[grooble]

Did you ever hear of Troy Hurtelboise and his fire paste?

 

[tap_sa]

You have found a metal that stands high temperatures, good. Now you have to ensure that it doesn't suck up heat faster than it radiates ie. heat too much, and <i>insulate</i> it from rest of the structure. I remember some thread soon after Columbia disaster where it was suggested making the whole orbiter from tungsten. While it might survive the re-entry intact, the crew inside would be toasted.

 

[grooble]

Add a thin layer of Troys firepaste and you have your solution. http://uplink.space.com/showflat.php?Cat=&Board=tech&Number=279695&page=&view=&sb=&o=&vc=1<br /><br />What other problems will there be? Does tungsten cost much?

 

[rubicondsrv]

Tugsten is very heavy and difficult to work with. <div class="Discussion_UserSignature"> </div>

 

[rubicondsrv]

It also has high thermal conductivity which means if you don't have either insulation or a cooling system between the skin of the spacecraft and the paylod the contents of the spacecraft will be roasted. <div class="Discussion_UserSignature"> </div>

 

[grooble]

The firepaste can repel heat of over 2000 degrees. A person on the other side of the paste could be touching it and not get burned. Check out the link above. <br /><br />"It apparently stopped 2000+ degrees with 1/8 of an inch of the coating, non toxic"

 

[ortemus74]

One could use ceramic tiles sandwiched between the contact points of the tungsten underbelly and the fuselage. Freon gas could be cooled and pumped into the cavity. <br /><br />Another option is spraying water mist onto the underbelly during re-entry the mist would act as a blanket and the steam from the mist would kept the tungsten underbelly from getting hot.

 

[grooble]

How thick does the tungsten sheet have to be to withstand the 3400 degrees?

 

[ortemus74]

http://www.tungsten.com/mtstung.html <br /><br />Melting Point: 3680K 3407°C 6165°F<br />I'd go with a quarter inch tungsten plate just to be on the safe side... <br />It could probably be an 1/8 of an inch but that's cutting it slim.

 

[grooble]

Is there known to be any of this on the moon?

 

[le3119]

I found this site www.MoonMiner.com/lunar_regolith.html, which seems to have reliable data on lunar resources. Note the pie graph: no Tungsten.

 

[nexium]

Tungsten carbide melts at 2870 degrees c. It (and hafnium carbide) are likely no more costly than the presently used tiles and can likely be made into a foam form simular to the present tiles. The present tiles likely resist atomic oxygen better than tungsten carbide and hafnium carbide. Hot metalic tungsten (melts 3410 c) and hot metalic hafniun burn like coal (Magnesium?) in an oxygen atmosphere, likely making both unsuitable. Neil

 

[vogon13]

IIRC, the 'R' value of tungsten carbide is drastically lower than the current tiles. Even a 'foamed' form of that material (if possible) would be insufficiently insulating in its application, even if it did not melt. <div class="Discussion_UserSignature"> <p><font color="#ff0000"><strong>TPTB went to Dallas and all I got was Plucked !!</strong></font></p><p><font color="#339966"><strong>So many people, so few recipes !!</strong></font></p><p><font color="#0000ff"><strong>Let's clean up this stinkhole !!</strong></font> </p> </div>