Ariane 5 rocket launches double science payload
BY STEPHEN CLARK
Posted: May 14, 2009
An Ariane 5 launcher rocketed through blue skies and into space Thursday with two European telescopes designed to give scientists unprecedented views of star birth and the relic light from the Big Bang.
The 166-foot-tall vehicle roared through mostly sunny skies during the rare morning launch from Kourou, which usually hosts evening flights leaving on commercial satellite delivery missions.
The Ariane 5 flew out of sight, shedding its boosters, nose cone and first stage in the first 10 minutes of the launch. The rocket's cryogenic upper stage fired for more than 15 minutes, pushing Europe's Herschel and Planck observatories into an unusually high-altitude orbit to reach their posts in deep space.
Both spacecraft were deployed less than 29 minutes after liftoff, completing the more than $2 billion launch.
Ground stations in Australia acquired the first signals from Herschel and Planck at 1349 GMT (9:49 a.m. EDT), confirming they survived the trip to space.
"They were released and the satellites are acquired," said Thomas Passvogel, project manager at the European Space Agency.
Controllers at the European Space Operations Center in Germany are checking the health of both satellites, but early indications are everything is working as expected, officials said.
"The excitement is enormous," Passvogel said.
The Ariane 5 was shooting for an orbit stretching nearly 1.2 million kilometers, or 741,682 miles, into space. Officials did not have numbers on the actual orbit the rocket achieved Thursday morning, but Jean-Yves Le Gall, Arianespace chairman and CEO, called the launch "perfect."
"Herschel and Planck have just hit the trajectory that will put them on track to reach the second Lagrange point, L2, and it's a big pleasure to share this success with you," Le Gall said to guests at the launch site.
The mission marked the 30th straight success for the Ariane 5. It was the second of up to seven launches of the heavy-lifter this year.
The L2 point is located 1.5 million kilometers, or about 932,000 miles, from the night side of Earth, where gravity from the planet and the sun balance to create a stable location for spacecraft studying the cosmos.
Spacecraft stationed at L2 are far enough away from Earth, the sun and the moon to be free of light interference, but close enough to rapidly communicate data to ground stations.
Controllers are planning small maneuvers for both spacecraft Friday if they need to make minor corrections on their path toward L2. Another round of thruster firings are on tap Sunday.
Planck will have to complete at least two extra maneuvers on June 6 and July 3 to alter its trajectory toward L2. Planck will enter a looping orbit at L2 with an average amplitude of about 250,000 miles.
Herschel is already on track for its larger targeted orbit at L2.
Both observatories should be at L2 by the end of July.
"In 10 weeks, the satellites will be fully commissioned and ready to go for the scientists," Passvogel said.
Commissioning will begin Saturday for Herschel and on Monday for Planck.
Thursday's launch was the end of three decades of work defining, designing and building the Herschel telescope. Planck development began in 1994.
"This dual launch is the crowning of some 20 years of hard work for the scientists who imagined these missions, the engineers who designed these satellites, the firms that built them and the ESA staff who coordinated all these efforts," said Jean-Jacques Dordain, ESA's director general.
"Herschel and Planck are the most complex science satellites ever built in Europe," Dordain said. "They were developed by an industrial team led by Thales Alenia Space France and comprising more than 100 contractors from 15 countries in Europe and the United States."
Dordain also addressed the scientists that will use the telescopes.
"You scientists are excused. You are to make progress. It's yours now," Dordain said.
Scientists from across Europe, the United States, Canada, Russia, China and Taiwan are participating in the missions.
"Now the real science will start," Passvogel said. "It's still work but this is another kind of work because now you have a machine you can point at something and do something with and observe something with."
Herschel to study cold, invisible universe
Europe's Herschel observatory, a massive spacecraft more than two decades in the making, will give scientists their best look yet into how new stars and galaxies form and evolve through billions of years.
The 7,500-pound spacecraft is shaped like a tube, standing nearly 25 feet tall with a diameter of nearly 15 feet. It is named for William Herschel, the German-born British astronomer who discovered Uranus and infrared radiation.
The telescope's three instruments will look into far infrared light wavelengths never before studied, allowing the sensors to see through dust clouds and deep into star-forming regions across the Milky Way and other galaxies.
"I like to say that if you want to understand the life of a star you make a comparison with the lives of people," said Goran Pilbratt, Herschel's project scientist at the European Space Agency.
Observatories like the Hubble Space Telescope that detect visible light can see "adult" stars and most infrared instruments can take pictures of "child" stars, Pilbratt said.
But Herschel will be able to see much more, thanks to a suite of high-tech detectors and a perfectly-crafted primary mirror spanning three-and-a-half meters, or about 11.5 feet, in diameter.
"We're going to see the embryos, the ones that are not born yet. We're going to see right into the wombs where stars are born," Pilbratt said.
Stars form inside relatively cool clouds of dust and gas that hide stellar incubation from normal telescopes designed to magnify what could be seen by the human eye.
"The birth of new stars takes place in these very optically opaque clouds of dust and gas," said Paul Goldsmith, NASA's Herschel project scientist.
Infrared telescopes like Herschel can see through the enshrouding clouds to see condensing gas and dust before stars can flicker to life.
"That's what I think is going to be most exciting, to really be able to get this almost unblocked, highly detailed view of what's going on inside these clouds," Goldsmith said.
Herschel is sensitive enough to even see star formation in other galaxies.
Another objective of the mission is to take a census of forming stars in our galactic neighborhood.
The observatory will look far back in time to study how galaxies formed and evolved up to 10 billion years ago, during the first three billion years after the Big Bang.
"Galaxies evolve by the formation of new stars, especially massive stars that then die and explode as supernovae and enrich galaxies with heavy elements. They put so much energy out that they really dominate the structures of these galaxies," Goldsmith said.
Scientists will also focus Herschel's telescope on debris clouds around other stars to learn more about how planetary systems form.
Closer to home, Herschel will help astronomers create highly-detailed chemical maps of objects in the solar system. The observatory will use spectrometers to probe the composition of comets, which scientists believe harbor the frozen building blocks of the solar system.
"With Herschel, we can resume the pioneering work undertaken with ISO, ESA's first infrared space observatory operating in the second half of the 90s, and we are building upon the experience gained to date by the world wide scientific community in the field of infrared astronomy," said David Southwood, ESA's director of science and robotic exploration.
ISO, the Infrared Astronomical Satellite, NASA's Spitzer Space Telescope, and the Japanese Akari observatory preceded Herschel in infrared astronomy.
Earth's atmosphere blocks infrared light from space, meaning scientists must launch instruments on spacecraft to observe the universe in infrared wavelengths.
Herschel will launch with 2,300 liters, or about 607 gallons, of cryogenic liquid helium to chill the telescope's coldest detector to a temperature of 0.3 Kelvin, or below -459 degrees Fahrenheit. The helium is projected to last about four years.
The detectors must be subjected to such frigid conditions to see faint emissions of cold objects scattered in the distant universe. Herschel will detect light from material as cold as -441 degrees Fahrenheit.
NASA contributed critical detecting equipment, electronics and other key technologies to two of Herschel's three instruments, boosting their observing capability.
A NASA Herschel Science Center has also been established at the California Institute of Technology's Infrared Processing and Analysis Center, which also oversees data gathered by Spitzer.
NASA's contributions are valued at $272 million, including spacecraft hardware and operational costs, according to an agency spokesperson.
The total cost of the Herschel mission is quoted at 1 billion euros, or nearly $1.3 billion in current exchange rates. That number equates to about 1 million euros for each day of Herschel's three-year primary mission, Pilbratt said.
Herschel's science mission can begin as soon as controllers finish testing the observatory's instruments and open the door covering the cryostat, allowing the instruments to cool down to operating temperatures.
Planck to take a baby picture of the universe
Planck will act as a cosmic time machine to give humans a look at the universe as it appeared less than 400,000 years after the Big Bang.
"Cosmology is the science that deals with the structure and the contents of the universe," said Jan Tauber, the mission's project scientist at the European Space Agency. "Planck is quite important for (everyone) who is interested in the universe that we live in."
The Planck observatory will observe the cosmic microwave background radiation left over about 380,000 years after the Big Bang. The CMB is considered the first light from the young universe after matter and light could exist independently as the universe cooled.
"Planck is going to take a picture of the universe when it was very young," Tauber said.
Scientists estimate the universe is about 13.7 billion years old and formed when a compressed ball of hot matter exploded outward in an unimaginably intense event called the Big Bang.
"It's like looking at the first day in the life of a human being," Tauber said.
The 4,235-pound spacecraft stands 13.8 feet tall and also has a diameter of about 13.8 feet.
The mission was named for Max Planck, a German physicist that established the quantum theory, which revolutioned scientists' understanding of atomic and subatomic processes.
Planck carries pressurized helium to cool the telescope's two instruments to temperatures approaching absolute zero.
The instruments must be cold enough to sense warmth from the cosmic microwave background in the furthest reaches of the universe, which averages about 2.7 Kelvin, or -455 degrees Fahrenheit.
Planck will measure subtle differences in the CMB across the entire sky.
"The signals we are trying to detect are variations about a millionth of the average (CMB) temperature," Tauber said.
"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, Planck project scientist at NASA.
NASA spent $117 million on Planck, providing amplifier and detector technologies and part of the observatory's cooling system.
Officials say Planck will measure the CMB up to the limits of fundamental astrophysics, obtaining as much information as can possibly be learned by studying the primordial radiation, according to ESA.
"With Planck, we are pushing the boundaries of our knowledge to the very limits of what can be observed according to theory," Southwood said. "It is a tremendous technical challenge but helping to bring about a great leap forward in our understanding of the origin and perhaps the fate of our Universe will be a tremendous reward."
"Planck is trying to measure a signal that would be comparable to measuring from Earth the natural heat emission of a small animal like a rabbit that would be placed on the moon," Tauber said.
Although Planck will be gathering incoming light at very low temperatures, the CMB had a temperature of nearly 5,000 degrees Fahrenheit when the light was emitted.
The energy cooled and stretched to longer wavelengths over time because the universe is expanding, according to scientists.
Planck will collect the light through a mirror with a diameter of 1.5 meters, or about 5 feet.
The observatory will map the CMB with higher fidelity than its two predecessors, NASA's COBE and WMAP missions.
"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," Lawrence said.
Officials expect Planck will begin scanning the sky about three months after launch. Plans call for the observatory to complete at least two all-sky maps by the end of the mission, which is currently expected around the end of 2010.
It may be three or four years before the Planck team is ready to present the mission's results, Tauber said.