Solar Storm Threatens Astronauts

One of the most unpredictable dangers facing astronauts in orbit is a sudden violent solar storm which can pump out life threatening amounts of radiation toward those who do not have the protection of the atmosphere. A large storm forced the Shuttle and Space Station crews to hunker down in sheltered areas:

A violent solar explosion sent a dangerous wave of radiation through space late Tuesday, prompting NASA to order the crews of Discovery and the International Space Station to take shelter overnight, according to Local 6 News partner Florida Today.

The solar flare erupted around 9:40 p.m., unleashing enough radiation to disrupt radio communications on Earth and in orbit while endangering astronauts circling 220 miles above the planet.

NASA flight surgeons and agency radiation experts determined that the burst of highly energetic particles approached a limit that made preventative action prudent, Florida Today reported.

Station commander Michael Lopez-Alegria and shuttle skipper Mark Polansky were told to move their crews to the most shielded areas in either spacecraft.

They include the middeck of the shuttle's crew compartment and temporary sleeping quarters in the station's U.S. Destiny science laboratory.

I remember reading James Michener's book Space in which a couple of the book's featured players are killed by a solar storm which occured while they were conducting a moonwalk. I'm not sure if the book overplays the danger, but clearly NASA was concerned about this one.

UPDATE: There's a solar storm coming:

Space weather forecasters revised their predictions for storminess after a major flare erupted on the Sun overnight threatening damage to communication systems and power grids while offering up the wonder of Northern Lights.

"We're looking for very strong, severe geomagnetic storming" to begin probably around mid-day Thursday, Joe Kunches, Lead Forecaster at the NOAA Space Environment Center, told SPACE.com this afternoon.

The storm is expected to generate aurora or Northern Lights, as far south as the northern United States Thursday night. Astronauts aboard the International Space Station are not expected to be put at additional risk, Kunches said.

Radio communications, satellites and power grids could face potential interruptions or damage, however.

Solar flares send radiation to Earth within minutes. Some are also accompanied by coronal mass ejections (CME), clouds of charged particles that arrive in a day or two. This flare unleashed a strong CME that's aimed squarely at Earth.

"It's got all the right stuff," Kunches said.