The fun will always end and astronomical satellites Herschel observations of the European Space Agency ESA are no exception. After more than 3 years in orbit, the ship with a large infrared telescope ever launched began stopping all scientific activities after the end of liquid helium used to cool the equipment aboard exhausted.
Launched by Ariane 5 rocket on May 14, 2009 at the Guiana Space Center, French Guiana Island, Herschel was sent to an area called Lissajous orbit, 1.5 million km from Earth. Under the Lissajous orbital mechanics is considered an almost periodic orbit in which an object can fly around the second Lagrangian point (L2) of a 3 objects without any impetus to . Itself Lagrangian point 2 (L2) is one of five positions in interplanetary space where a small object affected only by gravity can theoretically be stationary over the two larger objects, here the Earth and the Sun.
Herschel satellite have a total weight of 3.3 tons is equipped with a Ritchey-Chrétien telescope (RC) with a diameter of 3.5 m aperture, focal length and 28.5 m on the operation wavelength and far-infrared wavelengths less than 670 micrometers to 60 mm.
The main equipment includes a set of Herschel's Heterodyne for infrared heterodyne far (HIFI) - this is a super-resolution heterodyne spectrometer operating in 7 high-frequency band covering the infrared wavelength between 157 and 625 micron. Next, spectrometer and detector camera (PACS) and finally the acquisition of spectral images and photometry (SPIRE) contain a camera and a spectrometer operating in the infrared frequency band other than the SPIRE.
All 3 of these devices need to be cooled at a temperature of - 271 ° C in a cryogenic machine containing 2367 liters of super fluid helium, accounting for nearly 10% of the original weight of the ship. Besides liquid helium, the photovoltaic panels on the Herschel also contribute to create cooling shade. However, there is a spatial paradox is that even when the sun can quickly take the temperature of an object above the boiling temperature, putting objects into the shade can make temperatures drop below 0 hundreds degree but not enough to cool the devices integrated on Herschel.
Scientists predict the helium vessel will gradually evaporate and eventually the rest of helium was exhausted yesterday (April 29), even when Herschel began communicating daily activities with a ground control station in Western Australia. Signs “dying” of the ship appear on all our devices and quickly deactivated.
The primary objective of the Herschel telescope to study the formation of stars in our galaxy and beyond the range observed in the visible corner of the universe 14 billion years ago. Besides surveying thousands of active galaxies, Herschel also is used to learn about the birth of the planets in the star system near Earth, the molecules in interstellar space, asteroid and comet in Thai Solar System.
According to ESA, Herschel had done his duty very well. "Herschel has exceeded all expectations, giving us a treasure trove of data that will make astonishing astronomers busy for years to come," Alvaro Giménez Cañete professor, director of science and discovered by ESA's robot said.
Among the achievements, Herschel has given evidence that the billions of galaxies in the universe's first stars bring more than previously thought and suggests that the super massive black holes may affect star formation by removing gas from galaxies by radiation pressure. Herschel also studied the phenomenon of debris belt surrounding the star Formal haut, similar to the Kuiper Belt of the solar system and provide clues about the formation of planetary nebulae or research and the dust disk money around the star (protostar) shows the existence of a large amount of water is a million times the amount of water in Earth's oceans.
Scientist Göran Pilbratt of ESA's Herschel project said: "Hershel gave us a new insight into the hidden corners of the universe, just give us an unprecedented process prior to the formation of stars and galaxies, and that allows us to track the existence of water throughout the universe from molecular clouds to the stars recently formed, planetary disk compensation and comet tails.
Herschel has sent more than 35,000 scientific observations, with more than 25,000 hours of data from 600 programs and 2000 hours observing correction. According to the ESA, this is a very large data warehouse, paving the way for new discoveries in the future. Currently, Hershel will still keep in touch with the Earth in the next few weeks until completion ESA inspection ship. Then, Herschel will be pushed to a stable region trajectory around the sun, where it will rest in peace forever.