~ Space Weather Update~ Chance for M Class~ Spy Satellite?~ Fireball

WEEKEND AURORA WATCH: NOAA forecasters estimate a 60% chance of polar geomagnetic storms this weekend when a solar wind stream is expected to hit Earth's magnetic field. High-latitude sky watchers, especially those located around the darkening Arctic Circle, should be alert for auroras. Solar flare alerts: text, voice.

MAJOR FIREBALL EVENT, UPGRADED: NASA's Meteoroid Environment Office has upgraded its estimates of a major fireball that exploded over the southeastern USA around 2:30 AM on August 28th. Lead researcher Bill Cooke says "the fireball reached a peak magnitude of -13, brighter than a Full Moon, and cast shadows on the ground. This indicates that the meteoroid had a mass of over 50 kg (110 lbs) and was about 40 cm (16 inches) in diameter. It hit the top of Earth's atmosphere traveling 23.7 km/s (53,000 mph)." Watch the movie, then read more about the fireball below:

"As far as I know, this is the brightest event our network has observed in 5 years of operation," he continues. "There are reports of sonic booms reaching the ground, and data from 4 doppler radars indicate that some meteorites may have fallen along the fireball's ground track." (Note: The city in the ground track map is Cleveland, Tennessee, not Cleveland, Ohio.)

Using data from multiple cameras, Cooke has calculated a preliminary orbit for the meteoroid. The shape and dimensions of the orbit are similar those of a Jupiter-family comet. If meteorites are recovered from the Tennessee countryside, their chemical composition will tell researchers more about the origin of the fireball.

Realtime Meteor Photo Gallery

SPY SATELLITE SPOTTED: On Wednesday, Aug. 28th, a Delta IV Heavy rocket (the world's largest, according to the United Launch Alliance) blasted off from Vandenberg Air Force Base in California. Its secret payload was classified by the US National Reconnaisance Office. So much for secrets. Amateur sky watchers are already tracking the NROL-65 satellite as it circles Earth. Kevin Fetter video-recorded the spysat last night as it glided silently over his back yard in Brockville, Ontario, Canada:

"In the video," says Fetter, "the satellite flew right by kappa Ophiuchus." That star is variable with a magnitude ranging between +4 and +5. Judging from the video, the satellite is about as bright as kappa Oph, say +4.5. This means it is faint but visible to the human eye from dark-sky sites.

No one outside classified circles knows exactly what this satellite does. Speculation is centering on the possibility that it is a KeyHole intelligence satellite of KH-11 lineage. Keyhole satellites are a bit like the Hubble Space Telescope, except pointed at Earth instead of the heavens. NROL-65 could be going up to replace a similar satellite, USA 186 (05042A / 28888), launched from Vendenberg in October 2005.

Would you like to see NROL-65 for yourself? Download this app to turn your smartphone into a spysat tracker. Our Simple Flybys web tool is also tracking NROL-65. If it is looking at you, you might as well look back.

SPACE WEATHER RADIO UPDATE: As a result of indiscriminate "sequester" budget cuts, the USAF Space Surveillance Radar will be shut down at the end of September. Readers have asked what this means for Space Weather Radio. For years we have broadcast Space Surveillance Radar echoes from meteors passing over the facility. Anticipating the shutdown, our radio engineer Stan Nelson is changing frequencies. "I have erected a new 50 MHz 4-element beam antenna for the Digital TV carrier of 54.310 MHz and have it feeding the receiver at SpaceWeatherRadio.com," he explains. The echoes we hear now will be TV signals bouncing off the ionized trails of meteors. "I will be experimenting with the direction and signal strength over the next couple of days, so stay tuned."

Switch to: Europe, USA, New Zealand, Antarctica
Credit: NOAA/POES

Planetary K-index
Now: Kp= 2 quiet
24-hr max: Kp= 2 quiet
explanation | more data

Interplanetary Mag. Field
B_total: 9.2 nT
B_z: 2.5 nT south
explanation | more data
Updated: Today at 1936 UT

Coronal Holes: 30 Aug 13

Solar wind flowing from the indicated coronal hole should reach Earth on Aug. 30-31. Credit: SDO/AIA.