Twin NASA probes aimed at the Sun are sending home super-sized panoramas
of Earth's nearest star as they take up positions to track explosive solar
storms.
Instruments
and cameras aboard NASA's two Solar
Terrestrial Relations Observatory (STEREO) spacecraft have zoomed out for a
planetary orbit-hopping view that stretches from the Sun to Earth's orbit, a distance of
93 million miles (150 million kilometers). The panorama [image]
serves as a shakedown for STEREO's science tools
to take three-dimensional scans of the Sun's coronal
mass ejections (CMEs), the first of which are expected in April [new
video].
"This
panoramic view is absolutely unique," Russ Howard, principal investigator for
the STEREO instruments that took the new images, told reporters Thursday,
adding that the probes have already spotted a CME event. "We're still seeing
the evolution of this material as it goes out into to interplanetary space."
Howard
leads STEREO's five-imager Sun-Earth Connection
Coronal and Heliospheric Investigation (SSECHI) instrument
suite for NASA at the Naval Research Laboratory in Washington, D.C. [image].
CMEs are
massive eruptions from Sun that spew high-energy particles at
prodigious speeds which, if they pass by Earth, can pose
radiation hazards for astronauts in space, afflict
orbiting satellites and interfere with power and communications systems on Earth.
"They can
get their memories reset or power supplies wiped out," mission project
scientist Michael Kaiser, of NASA's Goddard Space Flight Center in Greenbelt,
Maryland, said of CME-susceptible spacecraft, during Thursday's
press briefing. "They need to know when [CMEs] are coming so they can be set in
safe mode."
STEREO's planned
two-year mission is expected to build near real-time 3-D views of those
eruptions by positioning twin Sun-watching probes at stations leading and
trailing the Earth in its orbit [image].
The mission, researchers hope, will yield better forecasts for severe space weather and determine how
CMEs speed up and slow down as they flow out from the Sun.
The
mission's two spacecraft spotted a CME event between Jan. 24 and Jan. 25, and
watched as the eruptions first sped away from the Sun at more than 750 miles (1,207
kilometers) per second only to slow to about 500 miles (804 kilometers) per second.
The observations also caught the last vestiges of the tail of Comet
McNaught, the brightest comet seen in 30 years, mission scientists said [image].
"This is a
discovery. ... We have never been able to see the progress of the CME from the
Sun, from its origin, all the way out," Dan Moses, a SSECHI science team member
at the Naval Research Laboratory. "We see that this is different from our
initial models."
Since their
October 2006 launch, STEREO's two probes, dubbed A and B for "Ahead" and
"Behind," have not yet traveled far enough apart to begin their
three-dimensional Sun observations. Once in their final positions in April,
STEREO A--ahead of Earth--will make a complete orbit around the Sun in 347 days,
while STEREO B-- behind and further out of Earth's orbit--will complete one
circuit in 387 days [image].
Mission
managers said the STEREO probes are in good health and have enough propellant
onboard to last a decade. The Applied Physics Laboratory at Johns Hopkins University in Laurel, Maryland, is overseeing the $550 million mission for NASA's
Goddard Space Flight Center.
Madhulika
Guhathakurta, NASA's STEREO program scientist at the agency's Washington, D.C.,
headquarters, pledged that STEREO's first 3-D Sun images will be released to
museums nationwide and via the Internet.
"These
images are just unbelievable," Guhathakurta said of the new panoramas.
NASA has
compiled a list of 3-D glasses
resources, available by clicking
here.
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