Mineral Oil In Vacuum?

Look up the properties on MatWeb, maybe?

I hope no one dumps any fish into such an aquarium as in the video....

Tried that but diddn't find anything

Thank You,

and too bad they don't give a boiling or freezing point.

I just wonder what state it would be in when it's near say ) deg C and in almost a pure vacuum. not quite but as close as space as possible.

hmmmm?

Yeah, I thought that was weird. Just stick a thermometer in it and heat until boiling, like maybe 150°C. You could do that at home, but you couldn't so easily cool it until freezing (wild guess -50°C?)

Not sure what your objective is, but if you expose it to a hard vacuum it will all go away, and redeposit itself elsewhere over time.

Hello all,

Thanks for the replies so far. It wont be a total vacuum, but for all practical purposes it will be. If we use the typical psi at sea level as being 14.695949 PSI,, I will be exposing the oil to a pressure of 0.042369 PSI. Not a pure vacuum, but close enough.

We could possibly build a capsule to keep it pressurized, but would prefer not to have to.

What we do as many of you have seen in the past is send experiments to the "Edge Of Space" for students in junior and high schools. We did a flight last summer for a large group of boy scouts. A you tube video summary can be seen here,

http://www.youtube.com/watch?v=HJ0IT4ZwtSo

We have been doing flights like these for over 22 years now.

And one major problem is temperature control. Certain altitudes it can be as cold as 70 below zero. But luckiliy these temps don't last too long a thick styrofoam box is all thats needed to protect the internal components and in 30 minutes we can punch right on through them into more balmy temps. 20 below to zero or so temps.

But what happens next has been a problem. Even tho it may be in a place where it's 20 below, we still experience at times final amplifiers overheating, and stuff like that. Yet just a few inches away the battery packs are loosing power because they are getting cold!

You all know the three modes of energy transfer, and most equipment rely mainly on convection to rid things like a transmitter of excess heat. well in an almost total vacuum this is gone.

We have tried to modify the heat sinks to make them more into a radiation capable of transfer, and it has helped. But still not enough, even placing the battery pack on the radiation panel,does indeed help. We want to try to enhance it.

Sitting on my floor is an old gallon paint can looking thing it is a transmitting load (Dummy Load) that during testing of transmitters you can hook up to simulate an antenna, all the energy instead of being transmitted and possibly causing interference to someone. this takes all it's energy and converts it into heat.

More or less all it is, is a large 50 ohm resistor immersed in a gallon of mineral oil to pull the heat out of the resistor quickly so it doesn't burn up.

It's seems scary that a liquid can do something like this, but mineral oil is neat stuff, electrically it just like it's not there it's like it's just thick air.

I love this video of a guy that made a liquid cooled computer in a fish tank aquarium.

http://www.youtube.com/watch?v=PtufuXLvOok&

We got to thinking of doing the same in one of our payloads. We could even pre heat the oil to keep it warmer as it passes through the 70 below zones on it's way up to the cruising altitudes. then once at altitude we easily can keep the final amplifier transistors cool because they'd be immersed in the oil, as well as that heat would now be available to help keep the batteries warm also.

Later on in the flight when we start loosing H2 through the balloon envelope we could even to aid in staying aloft use the il as a ballast drop where we can dump small amounts to lighten the payload.

But we can not find out what mineral oil does in a vacuum.

Joe

In another life I researched, developed, specified and, in some "super secret" projects, applied materials to spacecraft and payloads.

This is an excellent free source of outgassing information:

Outgassing Data for Selecting Spacecraft Materials System

I sent them literally hundreds of samples to test. There is now an ASTM spec. #595 if memory serves.

You may already be aware of this.

Good Luck.

Nope tell me more?

Most non-metals outgas in space. These "volatile condensible materials" (VCM) can then condense on sensitive surfaces, such as thermal control surfaces, electrical contacts, mirrors and lenses forming a film which renders the device inoperable, or at least compromises their performance.

The test goes like this. A sample is accurately weighed and placed in a chamber. It is pulled down to 10x-6 torr at 125°C for 24 hours. In the chamber is also a collector plate maintained at 25°C. The total weight loss is recorded, along with the weight of the materials that condensed on the cold plate. If the numbers are too high, the material isn't allowed.

Id' contact Goddard Space Flight Center and talk to Bill Campbell or Ernie Mielke, or whoever is running the lab now. These guys may both be dead by now, but someone should take time to speak to you.
Check out the web site first. ASTM-595 covers this test, too.

Good luck!