Sun Eruption That May Have Spawned Zombie Satellite Identified

Sun Eruption That May Have Spawned Zombie Satellite Identified
The left and center panels are NASA STEREO images of the April 3, 2010 solar coronal mass ejection about eleven hours after its inception, as viewed from STEREO-A and STEREO-B respectively. The right panel is a three-dimensional reconstruction of the morphology of the event, consisting of a flux rope with a shock wave driven in front of it
(Image: © Brian Wood/ NRL)

Scientists have identifieda massive eruption from the sun in April that reached all the way to Earth andmay be responsible for knocking out a satellite, creating a so-called "zombiesatellite."

The huge explosion ofplasma and magnetic energy, called as a coronal mass ejection (CME), occurredon April 3 and was observed by NASA's sun-watching STEREO spacecraft, accordingto the U.S. Naval Research Laboratory (NRL). The laboratory released new imagesof the solar storm last week.

The solarstorm appears to have disabled the Intelsat communications satellite Galaxy15, NRL officials said. Galaxy 15 lost contact with its ground controllerson April 5 and has been drifting around Earth ever since.

Solar storms are known toput satellites at risk. The charged particles in a storm can short outelectrical equipment.

The observations suggestthe coronal mass ejection flung material away from the sun at a phenomenal1,000 kilometers per second. The solar eruption was moving at 2.2 million mph(3.6 million kph) while it was still close to the sun on April 3. It then sloweddown to about 700 kilometers per second (1.5 million mph or 2.5 million kph)when it reached Earth on April 5.

There is an odd twist tothe Galaxy 15 satellite failure. While the satellite has stopped communicatingwith its ground control center, its C-band telecommunications payload (which providedbroadcast services to customers) is stuck on, earning it the "zombiesatellite" nickname.

"Coronalmass ejections, or CMEs, are powerful eruptions of plasma and magneticenergy from the sun's outer atmosphere, or corona," NRL officials wrote inthe July 7 statement. "When these sudden outbursts are directed towardEarth, they can have both breathtakingly beautiful and potentially damagingeffects." [Amazingnew sun photos.]

The study of the April 3 coronalmass ejection event was performed using NASA's Solar Terrestrial Relations Observatory(STEREO), a set of twin spacecraft on opposite sides of Earth that continuouslywatch the sun in what produces a stereo view, due to the wide separate of theprobes in space.

The unique lateral viewsprovided by STEREO were ideal for studying the kinematics and morphology of thedeveloping event, said Russell Howard, the STEREO mission's principalinvestigator at the Naval Research Laboratory.

Three-dimensionalreconstruction of the evolving cloud of electrified gas showed its form to be acrescent-shaped "flux rope" with a shock wave driven in front.

Prior awareness that the coronalmass ejection was headed straight for Earth came from the NRL-developedcoronagraph aboard the SOHO solar observatory, which is located at a spotbetween the Earth and sun. That Large Angle Coronograph-Spectrograph (LASCO) instrumenton SOHO observed a "halo" around the sun formed by the expanding andapproaching solar eruption, NRL officials said.

Meanwhile, the now-aimlesselectronic signal from Galaxy 15 has forced other communications satellites toconduct evasive maneuvers from time to time to avoid signal interference. Butthe chances of the Galaxy 15 spacecraft hitting another satellite are soremote, they are non-existent, Intelsat officials have said. This month, Galaxy15 will be flying near two other Intelsat satellites (Galaxy 13 and Galaxy 14).

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