Testing methods to measure liquids in microgravity
A lot of scientific research depends on accurate measurements, so that you can be sure you know what you’re testing. In biology and chemistry, this frequently means using a pipette- a tool that kind of resembles a very accurate eye dropper. Pipettes can be used to suck up a sample or solution and then eject precise quantities into new containers for further testing, mixing, or whatever. Researchers would like to be able to rely on these tools in space, but first they needed to be sure these tried and true devices would even work in microgravity. Time for a trip on the Vomit Comet!
The Vomit Comet is NASA’s microgravity simulation aircraft, with the current incarnation being a Boeing 727. The jet flies up at a 45° angle before leveling off for a few moments, and then diving back towards Earth. In the few moments of leveling off, occupants in the plane experience near-weightlessness, allowing them to test concepts and projects before investing further resources in sending them up to space. In this case, 160 maneuvers were used to see if pipettes were worth sending up to the International Space Station (ISS).
Working with weightless liquids
Three pipetting techniques were tested in these flights. The first used a modified pipette connected by a tube to the intended receptacle. While there was little mess in a more closed system like this, it was hard to control and operate. The second technique used more standardized equipment, but the disposable tips of the pipette were relatively wide, which broke the liquid’s surface tension enough to break up the coherence of the liquid. In addition to leading to possible leakage along the side of the test tubes, they also found bubbles were being introduced, which are nearly impossible to remove without gravity’s assistance in sorting relative densities in liquid. The final option was a pipette with a thinner tip, which left surface tension intact without difficulty or complications.
Biological samples in the comfort of your own space station
These tests open the door for more biological testing on the ISS. Rather than send blood samples back to Earth for analysis, astronauts will be able to do some tests themselves in space. The first point of focus will be this year’s Twins study, wherein astronaut Scott Kelly is spending a year in space while being compared to his terrestrial twin brother, Mark. Beyond that, deeper exploration into space will require that astronauts can perform a wide variety of tests and experiments, if only for their own health, and so it’s nice to know we already have some of the tools they’ll need with them.
Source: Zero-gravity genomics passes first test by Chris Cesare, Nature News