Story ID: 304SpaceWeather
Space Weather Can Affect Bizav Flyers
By: AIN Staff
Caption: Not only does space weather cause radio problems, but it can also add to flight crews’ radiation exposure.
Word Count: 669
The weather at 36,000 feet is CAVU. Winds are light. Your aircraft is gleaming and twinkling in the brilliant sunshine. To hear Kent Tobiska tell it, that is the problem.

“You may not be threatened by conventional weather, but there’s still space weather to contend with,” said the president and CEO of Space Weather Technologies. “It falls into three categories: radiation, high frequency (HF) communications disruption and an increased uncertainty or total disruption of GPS navigation.” At this year’s NBAA Convention, space weather is one of the workshops at the Friends and Partners in Aviation Weather forum Wednesday November 17 from 1 to 5 p.m. and Thursday November 17 from 8:30 a.m. to 4:30 p.m. The space weather workshop takes place during the Wednesday session.

Space weather is the study of how energy from the sun and other galactic phenomena interact with the Earth. Scientists and space meteorologists such as Tobiska, who is also director of the Space Weather Center at Utah State University, are just now gaining a meaningful understanding of how much more radiation can affect both crew and passengers in flight. For instance, 10 hours of flight at 37,000 feet is the equivalent of getting a chest X-ray.

“For every 6,500 feet above that, you get the equivalent of another chest X-ray,” Tobiska said. “So if you’re flying a business jet at 45,000 feet, you’re getting more than twice the radiation dose as you would flying at 37,000 feet.” Worse, he said, would be flight during a solar event such as a big flare erupting toward Earth. In those cases, flight crews are exposed to between two and 10 times the normal level of radiation.

Working with NASA’s Armstrong Flight Research Center, scientists are testing four different dosimeters, capable of detecting radiation exposure aboard high-flying aircraft. A fifth unit, approximately the size of an iPhone 6+, will begin testing in November. At the same time, the price of dosimeters is dropping. From $50,000 just two years ago, they have fallen in price to approximately $10,000 per unit. The goal, Tobiska said, is to get the unit cost to less than $1,000.

Another space weather issue, HF disruption, is especially bothersome to crews flying overseas or via polar routes. “That’s especially important when there’s no radar coverage,” said John Kosak, a weather specialist at NBAA Air Traffic Services.

“After 9/11,” Kosak said, “FAA required all carriers to have a guaranteed radio communications link entering or departing the United States. When you get a major solar event, especially in the polar regions, you have a tremendous problem dealing with [HF] signal skip.”

GPS WAAS approaches are vulnerable to space weather, as well. With little warning to flight crews or controllers, solar and galactic events can cause a sudden increase in the level of uncertainty demonstrated by GPS.

Satellite communications are also affected by space weather, although the extent of the interference is often determined by the altitude of the satellite above the Earth. In fact, there are three different effects space weather can have on satcom: interference with the ground unit; issues with the satellite; and issues caused by space weather in the atmosphere. These issues, which involve high-energy particles that originate in our sun or elsewhere in the universe, can cause memory upsets, dielectric charges and radiation damage to components on the ground and in orbit.

Satellites in low-Earth orbit are not as susceptible to interference or radiation damage, except when over polar regions. However, they may suffer orbital decay when hit with increased solar activity. That, of course, can shorten the satellite’s effective life.

Utah State’s Space Weather Lab has developed the Gauss-Markov Global Assimilation of Ionospheric Measurements (GAIM) system, with real-time and forecasted reports on winds, temperature and space weather conditions in the upper atmosphere and ionosphere. With 357 stations monitoring the total electron content (TEC) in the ionosphere, GAIM issues a report every 15-minutes containing up to 10,000 measurements. o