NASA Remembers

Today NASA remembers the 17 daring and courageous  astronauts who lost their lives during America's space program. Several NASA centers including Johnson Space Center in Houston, Texas, Marshall Space Flight Center in Huntsville, Alabama and Kennedy Space Center in Cape Canaveral, Florida are holding observances for employees, family, and the public. 

Strangely, the loss of NASA personnel all happened days apart in the winter of different years (e.g., Apollo 1 fire - Jan. 27, 1967; Challenger explosion after liftoff - Jan. 28, 1986; and Columbia breakup upon reentry - Feb. 1, 2003). 

I was working at Johnson Space Center during the Challenger explosion and knew well several of the crew. Ron McNair's children went to the same preschool as mine and we chatted often when dropping off and picking up. Others, I worked with on mission planning. As everyone involved in the space program can agree, these deaths were personal losses. We shopped with, went to church with, commuted with, and served with these NASA heroes. I was still living in Clear Lake, TX when the ill-fated Columbia spacecraft and crew were lost. Grief revisited - for me and the nation.

Unfortunately, we often forget how dangerous space exploration is, but the rewards are multiplied a hundred fold or more via NASA science, medical, materials, and engineering spin offs. To me, these lost colleagues lived extraordinary lives and deserve our thankful remembrance. Go science!

Gamma-ray Flashes & Storms

Thunderstorms create about a 1000 quick bursts of gamma rays (i.e., high energy light on Earth). Recent data from NASA's Fermi Gamma-ray Space Telescope compared to ground-based radar and lightning detectors, gave scientists detailed information on the different types of thunderstorms and their produced energy.

Terrestrial gamma-ray flashes (TGFs), were discovered in the 1990s by NASA's Compton Gamma-Ray Observatory. TGFs, lasting less than a thousandth of a second, are poorly understood.

"Remarkably, we have found that any thunderstorm can produce gamma rays, even those that appear to be so weak a meteorologist wouldn't look twice at them," said Themis Chronis, who led the research at the University of Alabama in Huntsville (UAH).

The Fermi data, combined with info from ground-based radar and lightning, shows that terrestrial gamma-ray flashes come from a diversity of storms and may be more common than earlier expectations. In fact, the upper part of an intracloud lightning bolt disrupts the storm's electric field creating an avalanche of electrons that surge upward at high speed. These fast-moving electrons are deflected by air molecules and emit gamma rays, creating a TGF.  


The new study confirms previous findings that TGFs tend to occur near the highest parts of a thunderstorm, between about 7 and 9 miles (11 to 14 kilometers) high.

As climate change unfolds, it will be interesting to see if TGFs increase or decrease with storms. I'm sure the Fermi folks will keep an eye to the skies. Go science!