Ice and Spin Launch... Viable? Price is No Show Stopper... Only Physics

[Spacescifi]

Ice is a very useful non-toxic resource.

 

Questions: In theory there is a size limit to how big we could build a spin launch system to launch to orbit. For the sake of discussion let us assume we build a massive spin launch facility that can literally launch both the first and second stages of starship worth of mass through the lower atmosphere so that by the time they need to use engines the air is really thin anyway.

 

Ice comes into play by capping a long solid ice rocket nose on so that when it launches the ice ablates rather than hull in the lower atmospherr.

 

Furthermore there are various ways to slow the melting of ice by adding additives to it.   but obviously we want the ice to have melted or vaped off by the time the rockets reach orbit in space.

 

Thoughts?

 

Worth it or not?

 

If it is not someone may say it will require so much ice that you won't have a meaningful payload..

 I am skeptical of that though because as I said, ice can be slowed in the melting process by using additves to make it.

Edited August 1, 2022 by Spacescifi

[cubinator]

Aren't there better ablatives than ice? Lighter ones? Like cork, which also is pretty non-toxic.

[Shpaget]

Just now, cubinator said:

Lighter ones? Like cork, which also is pretty non-toxic.

Not only that, but it also grows on trees.

[cubinator]

Here is a table of specific heats of various materials, ice and cork are pretty similar with cork being around 1.9 kJ/(kg*K)

https://www.engineeringtoolbox.com/specific-heat-solids-d_154.html

Liquid water is quite a bit higher but I doubt you'd get it to stick around long enough to capture much heat in that kind of airstream.

Edited August 1, 2022 by cubinator

[Spacescifi]

1 minute ago, cubinator said:

Here is a table of specific heats of various materials, ice and cork are pretty similar with cork being around 1.9 kJ/(kg*K)

https://www.engineeringtoolbox.com/specific-heat-solids-d_154.html

 

So if cork weighs less we could use that.

 

I guess my argument is that launching heavy loads into space via spin launch is seemingly quite possible so long you use a sacrificial ablative nose.

 

Ironically, returning back from space a spaceship could coat the hull with asteroid rock or ice as well to ablate instead of the hull.

 

Use glue to adhere the stuff to the hull lol.

Edited August 1, 2022 by Spacescifi

[Shpaget]

9 minutes ago, cubinator said:

Here is a table of specific heats of various materials, ice and cork are pretty similar with cork being around 1.9 kJ/(kg*K

To be fair, and joking aside, for ice you should add heat of fusion, which is additional ~330 kJ/kg.

Edited August 1, 2022 by Shpaget
units....

[kerbiloid]

At 2 Mach speed a plane hull gets +120°C hot, which exceeds the water boiling point.

At several km/s speed the icerocket will melt together with ice.

[Spacescifi]

1 hour ago, kerbiloid said:

At 2 Mach speed a plane hull gets +120°C hot, which exceeds the water boiling point.

At several km/s speed the icerocket will melt together with ice.

 

Why? The steam trailing from the nose will be cooling the hull as it blows past anyway.

 

Also with math it is possible to calculate just how much ice or cork you need to ablate to reach the upper atmosphere for running the rocket engines.

[Shpaget]

7 hours ago, Spacescifi said:

Also with math it is possible to calculate just how much ice or cork you need to ablate to reach the upper atmosphere for running the rocket engines.

I strongly suspect that mats alone won't get you far, and sooner rather than later you'll need a hypersonic wind tunnel.

[monophonic]

On 8/1/2022 at 6:06 AM, Spacescifi said:

So if cork weighs less we could use that.

Cork also has the advantage of not melting or sublimating on its own. Temperature control in a vacuum chamber (remember, spin launch accelerates in a vacuum) isn't exactly off the shelf technology either, I believe.

[kerbiloid]

A bioship.

Permanently grows a horny epidermis on top (like a horn or a nail) and needs spaceflights to grind it.

Born to fly!