Posts Tagged ‘Chemistry in Space’
You are my density … I mean Destiny*
by azmanam on Apr 09 2010 (7835 Views)(for other entries in the Chemistry in Space series, click here)
Chemistry in space has been greatly aided by the addition of the Destiny Laboratory Module (see also: here for overview, and here for images) to the International Space Station. Destiny was delivered by the Space Shuttle Atlantis during STS-98 in February 2001. It is the first permanent operating orbital research station since Skylab was vacated in February 1974. Destiny is a cylinder measuring 28 feet long and 14 feet wide. Inside, there are 24 ‘racks’ (6 on each side) measuring 73 inches by 42 inches. The racks can be configured for storage, life support systems, or – more importantly – science experiments (check out the interactive on this page). 13 racks are available for science, while 11 are used for other purposes.
One rack bay remains open and houses the highlight of the module: a 20 inch optically perfect window made of telescope-quality glass – the largest produced for use in space. It allows the use of high quality video and still cameras primarily for capturing images of Earth in detail not before possible. One rack bay houses the Minus Eighty Degree Laboratory Freezer for ISS (MELFI). It has 4 dewars of 75 liters which can hold samples of various sizes and shapes and keep them at variable controlled temperatures. Currently, temperatures of -80 degC, -24 degC and +4 degC are in operation on the ISS.
The purpose of Destiny is to provide space for scientific research, including experiments in the physical sciences. Experiments are designed and built into the shape of one rack, which is ported into space and installed in Destiny. Racks can be built to be controlled by astronauts aboard the ISS or remotely by scientists on Earth. Destiny is joined by Columbus and Kibo as the main research ‘wing’ of the ISS. Columbus is the science laboratory contributed by the European Space Agency and Kibo is the science laboratory contributed by the Japanese space agency JAXA. Kibo also includes a ‘terrace’ where experiment payloads are fully exposed to the space environment.
Check back for stories of experiments conducted in the microgravity of space aboard the ISS. There’s some pretty awesome research being undertaken.
*Bonus points if you can tell me what movie that’s from 
Astrobiology: The Search for Life on Mars
by azmanam on Feb 26 2010 (7538 Views)
Photo: Techchee.com
(for other entries in the Chemistry in Space series, click here)
This doesn’t exactly fit in with the direction I was planning on taking with the posts on space science, but a story on MSNBC.com on Wednesday got my attention. The story discusses NASA’s long endeavor into the search for life outside of Earth. It used to be called exobiology (which I find to be an awesome name), but is now referred to as astrobiology.
NASA has previously attempted to find life on Mars with the Viking program in the 1970s. Probes were sent to Mars to look for life… Earth life, that is. The tests the probes ran attempted to find life that would exist at physiological conditions on Earth, a supposition that perhaps seems silly in hindsight.
An option in line with NASA’s recent change in direction could have the potential to bring Martian samples back to Earth for another attempt to find life on Mars. The program – still in theoretical infancy – would last some 3-4 years and could begin in 2018 with sending a joint US/European rover to Mars to collect samples. In 2020, a return vessel would go to Mars, get the samples, and return.
The story talks about the potential hazards of bring unknown astrobiological samples to Earth and the need to handle them in the equivalent of a Biosafety Level 4 Lab.
Anyway, my point in bringing this up is to share with you a short story – a commentary, really – by one of my favorite science fiction writers ever: Isaac Asmiov. Asimov (also a former biochemist at Boston University) developed the Three Laws of Robotics and is the author of the original robot series that inspired movies such as I, Robot and Bicentennial Man. If you haven’t read any of his work, I highly recommend one of his collections of short stories, such as The Complete Robot.
The commentary you should read is titled “Not as We Know It: The Chemistry of Life” and outlines what NASA scientists should keep in mind: life outside of Earth probably won’t look like life on Earth.
(in talking about life on Jupiter): An objection that might, however, be raised against the whole concept of an ammonia background for life, rests on the fact that living organisms are made up of unstable compounds that react quickly, subtly and variously. The proteins that are so characteristic of life-as-we-know-it must consequently be on the edge of instability. A slight rise in temperature and they break down.
A drop in temperature, on the other hand, might make protein molecules too stable. At temperatures near the freezing point of water, many forms of non-warm-blooded life become sluggish indeed. In an ammonia environment with temperatures that are a hundred or so Centigrade degrees lower than the freezing point of water, would not chemical reactions become too slow to support life?
The answer is twofold. In the first place, why is “slow” to be considered “too slow?” Why might there not be forms of life that live at slow motion compared to ourselves? Plants do.
He continues on to describe, in his opinion, what life might look like under the natural conditions of the various planets. What the background medium would have to be and what the life-sustaining molecules would have to look like. A fascinating read and a must read, in my opinion.
Boiling in Space: What Happens in the Absence of Gravity?
by azmanam on Jan 27 2010 (3914 Views)(for other entries in the Chemistry in Space series, click here)
Who knew boiling a liquid was so complicated? When you put a pot of water on the stove or heat your reaction-in-toluene solution in an oil bath several things happen. The liquid closest to the heating element starts to get hot. Convection circulates the hot liquid up and the cold liquid down due to the density differences of hot and cold liquids. Eventually, the liquid near the heating element becomes hot enough to move into the vapor phase and bubbles start to form. Buoyancy causes the bubbles to float to the surface and pop, while more convection continues to circulate the water. Eventually, you get a rolling boil.
Everything changes in the microgravity environment of space. Buoyancy and convection no longer play a role. The heated fluids no longer circulate and the bubbles no longer naturally rise to the surface. So what happens when you try to heat a liquid to boil in microgravity? Astronauts tested this during the course of several space shuttle missions during the 1990s. They arrived at some very interesting conclusions.
First, the liquid nearest the heating element starts to get hot, just as it does on Earth. But it doesn’t rise and circulate due to convection. It just gets hotter and stays next to the heating element. It eventually gets hot enough to move into the vapor phase, just as it does on Earth, but the bubbles don’t rise to the surface and pop. Instead, they stay next to the heating element and coalesce into one giant bubble. Eventually, the size of the bubble becomes larger than the heating element and there is no longer any liquid in contact with the heating element. This insulates the liquid from the heating element and leads to a “dry out” where there is no more boiling and the temperature of the heating element “begins to soar.”
(click on the image to go to the NASA page describing Zero G Boiling and to see an awesome movie of boiling in action)
All of this is predicted by theory, but it’s nice to have the chance to do some of those proof of principle experiments for the first time ever. It reminds me of what some of the pioneers of science must have felt when working out some of the fundamental theories of chemistry and physics that we don’t even realize we take for granted today.
An interesting variation of this experiment was conducted impromptu by an astronaut on the International Space Station in 2003. Don Pettit* was performing repair operations using a soldering iron. He decided to put a few milliliters of water on the hot surface. The water droplet formed a blob around the soldering iron and kinda wobbled there. As expected, the water heated up and began to boil. Surprisingly, though, this time the boiling looked much similar to boiling on Earth.
My working theory is the small amount of water and the inherent jostling of the system (the soldering iron looks like it was held by hand in front of the camera) caused enough motion in the water to move the bubbles around. The bubbles could bump into each other and coalesce. The size of the bubbles quickly reached the surface (unlike the bulk boiling experiment described above) and were allowed to pop. Thus, it is by accident, in my opinion, that the boiling looks like it would on Earth. It’d be interesting to repeat the experiment with the soldering iron held steady by vice grips or something.
(click on the image to go to the NASA page on the soldering iron boiling experiment and to see an awesome movie of this microgravity microboiling in action)
Here’s an overview page of boiling in space.
Here’s the NASA page on the 1990s boiling experiments.
Here’s the NASA page on the impromptu soldering iron boiling experiment.
*Also inventor of the super awesome zero-g coffee mug.
Sodium Chloride
by azmanam on Jan 11 2010 (6228 Views)(for other entries in the Chemistry in Space series, click here)
The below picture is of sodium chloride crystals. I’ve made them dozens of times in left over aqueous layers that have been in my hood so long that all the water evaporated.
Crystalline sodium chloride is one of my favorite crystals to grow. Very easy (although it takes a while), the crystals can get quite large and beautiful. And they have the characteristic X running through them. Especially awesome to me, because I did my undergrad at Xavier University. It’s nice to know that even my chemistry loves XU
What makes this picture so cool, though, is the crystals were grown in space. The picture is from NASA’s Image of the Day. The crew aboard the International Space Station’s Destiny lab grew the crystals in a water bubble as part of the program to do chemistry in space. From NASA:
Looking for all the world like a snowflake, this is actually a close up view of sodium chloride crystals. The crystals are in a water bubble within a 50-millimeter metal loop that was part of an experiment in the Destiny laboratory aboard the International Space Station and was photographed by the Expedition 6 crew.
Space has long fascinated me, and I’ve been trying to get the info and motivation to start a miniseries on chemistry in space. So I guess today’s IotD is a good way to begin. Stay tuned over the next several weeks to hear more about awesome chemistry in space!
