Astronaut and Chemical Engineer Blogs from International Space Station

If you want to know what's happening on board the International Space Station as it orbits 250 miles above earth, astronaut Don Petttit, who arrived in late December, has been writing a detailed, photo-filled, blog called "Letters to Earth," and sending his posts to gravity-bound readers whenever he has enough time to collect his thoughts between research experiments and the constant repairs that keep the complex station running. Pettit will be onboard when Elon Musk's SpaceX Dragon module arrives carrying vital supplies. As he said in a preflight interview (video):

Dan Burbank (the commander) and I will be snaggin' the first Dragon, assuming everything goes as scheduled... it's a new era where we have commercial entities that are lining up to take supplies to and from space station.

SpaceX, which already had two successful launches to its credit, is now among the yeoman space tugs that ferry fresh supplies up to the orbiting space station. Pettit recently released a blog post about the arrival of the Edoardo Amaldi, a European space tug that docked

at the Space Station. It delivered propellant, oxygen and drinking water, which was all pumped into the station's tanks; It also supplied vital scientific equipment, spare parts, food and clothes for the astronauts.

Repairs on the edge of space

Since this is Pettit's third trip aboard the ISS, he's had many "it could only happen here moments." Recently he recalled when he installed the station's new toilet and water recycling system in 2008, which he fondly calls a "chemical engineer's dream:"

The second piece of equipment installed (which would receive the waste from the new toilet) was a small chemical plant. It contained a distillation apparatus, catalytic reactors, pumps, filters, and plumbing. It was a chemical engineer's dream. The liquid effluent from the toilet was plumbed to the inlet of this machine.

He then attached hoses to the new galley's injection port for filling drink bags and freeze-dried food with water. So what goes in one end is processed and reused at the other. Watch a 2008 video as Pettit makes and drinks coffee from recycled toilet water:

With this complex technology, essentially a working prototype, the astronauts are truly on the frontier. It breaks down - constantly. And of course, according to Pettit, the crew is always repairing and improving it. Fortunately, there

is also a steady stream of spare parts arriving from Earth. He calls this process engineering research, and considers it one of the more important activities on space station:

Closing the water loop will be essential when humans venture away from Earth for long periods of time. If the toilet fails on a mission to Mars, the crew will run out of water and die.

He imagines that the first crews arriving on Mars, too distant to easily restock broken gear, will thank his "urine-stained hands." Read the entire "Our Fancy Coffee Machine."

The 1 millionth space station photo

Pettit has also been credited with taking the 1 millionth photo from the International Space

Station. He captured this stunning image while racing through space 240 miles above the Tasman Sea. He later added the photo to his Twitter account, where he posts updates and images from this outpost in space. As a manic multi-tasker, Pettit also documents his experiments, including his "diary of a space zucchini." If you page back and start reading his blog from the liftoff from Russia in December, you also get to know a man who enjoys living on what he calls the "new frontier" - risks and all - and considers himself the latest vanguard of civilization's manifest destiny. An ardent NASA fan has taken many of Pettit's pictures and edited them along with the station's live video feed to produce this stunning celebration of space exploration.

Where has your chemical engineering degree taken you?

Photos: Don Pettit