Herschel and Planck Share Ride to Space

MEDIA RELATIONS OFFICE
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Whitney Clavin 1-818-354-4673
Jet Propulsion Laboratory, Pasadena, Calif.
whitney.clavin@jpl.nasa.gov

NEWS RELEASE: 2009-077 May 5, 2009

Herschel and Planck Share Ride to Space

PASADENA, Calif. -- Two missions to study the cosmos, Herschel and Planck, are scheduled to
blast into space May 14 aboard the same Ariane 5 rocket from the Guiana Space Center in French
Guiana. The European Space Agency, or ESA, leads both missions, with significant participation
from NASA.

"The missions are quite different, but they'll hitch a ride to space together," said Ulf Israelsson,
NASA project manager for both Herschel and Planck. "Launch processing is moving along
smoothly. Both missions' instruments have completed their final checkouts, and the spacecrafts'
thruster tanks have been fueled."

Israelsson is with NASA's Jet Propulsion Laboratory, Pasadena, Calif., which contributed key
technology to both missions. NASA team members will play an important role in data analysis and
science operations.

The Herschel observatory has the unique ability to peek into the dustiest and earliest stages of
planet, star and galaxy growth. The spacecraft's astronomy mirror -- about 3.5 meters (11.5 feet) in
diameter -- is the largest ever launched into space. It will collect longer-wavelength light in the
infrared and submillimeter range -- light never before investigated by an astronomy mission.

"We haven't had ready access to the wavelengths between infrared and microwaves before, in part
because our Earth's atmosphere blocks them from reaching the ground. We will now have access to
these wavelengths thanks to Herschel's large, cold telescope in space, and its detectors' improved
sensitivity," said Paul Goldsmith, the NASA project scientist for Herschel at JPL. "Because our
views were so limited before, we can expect a vast range of serendipitous discoveries, from new
molecules in interstellar space to new types of objects."

The coolest objects in the universe, such as dusty, developing stars and galaxies, appear as dark
blobs when viewed with visible-light telescopes, so astronomers don't know what's happening
inside them. But at longer wavelengths in the far-infrared and submillimeter range, cool objects
perk up and shine brightly. Herschel will detect light from objects as cold as minus 263 degrees
Celsius, or 10 Kelvin, which is 10 degrees above the coldest temperature theoretically attainable.
To do this, the observatory's instruments must be cold, too. Onboard liquid helium, which is
expected to last more than three-and-a-half years, will chill the coldest of Herschel's detectors to a
frosty 0.3 Kelvin.

Planck has a different goal. It will answer fundamental questions about how the universe came to
be, and how it will change in the future. It will look back in time to just 400,000 years after our
universe exploded into existence nearly 14 billion years ago in an event known as the Big Bang.
The mission will spend at least 15 months making the most precise measurements yet of light at
microwave wavelengths across our entire sky -- including what's known as the cosmic microwave
background. This microwave light has even longer wavelengths than what Herschel will see, but
it's not from cool objects. In this case, the light is from the hot, primordial soup of particles that
eventually evolved to become our modern-day universe. The light has traveled nearly 14 billion
years to reach us, and, in that time, has cooled and stretched to longer wavelengths because space
is expanding.

By measuring minute variations in the cosmic microwave background as small as a few parts per
million, Planck will give us a new and improved assessment of our universe -- its age, composition,
size, mass and geometry. We'll also learn more about the theorized early inflation of our universe,
when it is thought to have expanded 100 trillion, trillion times. That's just one trillion, trillion,
trillionth of a second after the Big Bang.

"The cosmic microwave background shows us the universe directly at age 400,000 years, not the
movie, not the historical novel, but the original photons," said Charles Lawrence, NASA project
scientist for Planck at JPL. "Planck will give us the clearest view ever of this baby universe,
showing us the results of physical processes in the first brief moments after the Big Bang, and the
starting point for the formation of stars, galaxies, and clusters of galaxies. The clear view is a result
of Planck's unprecedented combination of sensitivity, angular resolution, or sharpness, and
frequency coverage."

Like Herschel, Planck will be cold; in fact, one of its instruments will be cooled to just 0.1 Kelvin.
But it won't carry liquid coolant. Instead, it will chill itself with innovative "cryocooler"
technology, developed in part by JPL.

Both spacecraft have been mated to their rocket and are being readied for launch. Shortly after
liftoff, they will separate from the rocket and follow different trajectories. By two months later,
the missions will have made their way to their final, distinct orbits around the second Lagrangian
point of the Earth-sun system, a point in space 1.5 million kilometers (930,000 miles) from Earth,
or four times farther from Earth than the moon. This point is on the other side of Earth from the
sun, providing the spacecraft with dark, expansive views of the sky. It is also far enough away that
the heat from Earth and the moon won't warm up the telescopes.

Herschel is a European Space Agency mission, with science instruments provided by a consortium
of European-led institutes, and with important participation by NASA. NASA's Herschel Project
Office is based at JPL. JPL contributed mission-enabling technology for two of Herschel's three
science instruments. The NASA Herschel Science Center, part of the Infrared Processing and
Analysis Center at the California Institute of Technology in Pasadena, supports the United States
astronomical community. Caltech manages JPL for NASA. More information is online at
http://herschel.jpl.nasa.gov/ .

Planck is a European Space Agency mission, with significant participation from NASA.
NASA's Planck Project Office is based at JPL. JPL contributed mission-enabling technology
for both of Planck's science instruments. NASA, U.S. and European Planck scientists will
work together to analyze the Planck data. More information is online at
http://planck.caltech.edu .

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