Earth and Moon. Photo: NASA/GSFC

The theory that microbial life once came to Earth on a meteorite from another planet is beginning to be tested. Wednesday, a NASA rocket carried into space special microorganisms from research at the University of Maryland Biotechnology Institute (UMBI).

The tiny space pioneers rode an apogee, or suborbital, flight path similar to the historic 1961 flight of astronaut Alan Sheppard. The passengers this time were four dime-size cultures, each holding about 100 million cells of the microbes to be exposed to space vacuum and solar radiation for 10 minutes.

For the first time, scientists with UMBI's Center of Marine Biotechnology (COMB) and NASA will also study the direct effects on living cells of the sun's extreme ultraviolet, or EUV, radiation. This is radiation that does not penetrate the Earth's atmosphere.

"We routinely look for DNA repair systems in extreme microbes called Archaea that might be useful in biotechnology or medical research," says Jocelyne DiRuggiero, the project leader at COMB. "And, in this case, we may also want to know what kind of lesions EUV can cause to the DNA of these microorganisms."

Archaea are microbes that typically live in extreme conditions, such as high temperature, pressure, sulfur, methane or radiation. The space-going microbes are already known to survive high temperatures and some radiation.

NASA's Joseph M. Davila, principal investigator for the flight, says, "Exposure to direct UV particles from the sun is not a well-known field. We know a bit about short gamma rays, but with EUV, not much is known at all about how to be protected from these fields."

Part of a four-year $400,000 partnership with NASA, the UMBI experiment is "hitchhiking" on the latest launch of the Solar EUV Rocket Telescope and Spectrograph, or SERTS, explains DiRuggiero,

Since 1997, fast, slender 19-foot sounding rockets carrying SERTS have helped NASA study sun activity and "cross-calibrate" data from the more sophisticated solar instruments aboard their SOHO satellite, Davila notes.

He says the microbe experiments may expand into orbital missions on a space shuttle.

The rocket during pre-flight tests. Photo: NASA

"First, we are trying to demonstrate that this kind of work will yield interesting results and we want to try our instruments (on the SERTS flight)."

The first microbes to be tested on the SERTS do not yet have a biological name. But their training regimen has been rigorous, according to COMB research professor Frank Robb.

"We thought this strain was a good candidate. We found it living in the sediments of Potts hot springs in Yellowstone National Park, where it was exposed to steamy plumes, alternating with hot, dry conditions."

Back at the COMB laboratories in Baltimore, Md., Renu Nandakumar, postdoctoral researcher, isolated the heat-loving strain and grew it up into cultures. She found that the strain survived gamma rays and a hard, or space-like, vacuum. Robb and DiRuggiero say the strain showed robust qualities, making it the right stuff for the SERTS flight.

Next, Dennis Spencer, a high school student at Baltimore Polytechnic, whose summer internship at COMB included preparing such microbial cultures, hand-carried them on an airplane to White Sands.

A second microbe, a radiation-resistant bacteria, Deinococcus radiodurans, extensively studied by the Department of Energy, also is on the launch as a control in the experiment.

The COMB researchers helped NASA engineers retrofit the SERTS instruments with microbe sample holders that were later shake tested to simulate the flight. The main NASA mission is to run experiments to study the sun's outmost atmosphere, called the solar corona.

COMB investigates one of the world's largest Archaea research collections.