After several weeks of soldering wires and sealing leaks, Rita and I were finally ready to get some Martian simulation going. Because the scientific process should always be transparent, here’s your personal guide to making those lovely irradiated magnetite samples you’ve always wanted.
Now don’t try this at home, kids.
1. Flush the glove box with nitrogen, three times for 15 minutes each. By filling the glove box with nitrogen, we ensured that in the unlikely case of a leak in the chamber, the surrounding atmosphere was unreactive. Rita and I made sure to stand in the hallway when the nitrogen was on, to avoid any unintended unconsciousness.
2. Put the magnetite on the tray and place it into the transfer chamber. We created a vacuum in the chamber, then filled it with nitrogen from the glove box. We did this vacuum-and-fill process three times to make sure no external atmosphere got into the glove box when we transferred in the sample tray. This is important – it’s not a very good Mars simulation chamber if there’s a ton of Earth’s atmosphere in it. We used a glove box that looks like the one below. (Image from Wikimedia Commons.)
- How do you move things around when they’re already in the glove box? The glove box is totally sealed, so we use these awesome built-in gloves to handle the samples once they’re inside. But use caution: wearing these seemingly-invincible contraptions may make you feel and act like a true mad scientist.
3. Take the samples from the transfer chamber, and put them into the simulation chamber. Using our invincibility gloves, we sealed the sample tray inside the small Mars chamber. These are the magnetite samples we used: a chunk from Greenland, a chunk with olivine inclusions, and a very fine powder.
4. Suffocate the samples. We vacuumed the chamber using first the back pump, and then the turbomolecular pump, so it’s nice and airless. We then let in 18 millibars of CO2 (a millibar is a unit of pressure – one millibar is about the pressure exerted by a penny lying flat). Remember, only the chamber that becomes a vacuum – the surrounding glove box is still filled with nitrogen.
5. Turn on the UV light. You wouldn’t bake a cake without turning on the oven, so why would you even think about doing this experiment without the radiation?
6. SCIENCE HAPPENS! We left the samples under the radiation for two weeks, checking the pressure and UV lights daily to make sure everything was working properly.
On August 11, we removed the samples to be analyzed. I know you’re dying to find out if the radiation mutated our magnetite into miniature Martians, but you’ll just have to wait for the next blog post.