Herschel space telescope
|Begin:||May 14, 2009, 13:12 UTC|
|Starting place:||CSG , ELA-3|
|Launcher:||Ariane 5 ECA|
|Flight duration:||3 years and 10 months|
|Status:||in orbit, out of order|
|Rotation time :||1 year|
Herschel Space Observatory , shortly Herschel is the name of one of the ESA -developed 3.4-ton infrared space telescope, which together with the Planck space telescope with an Ariane rocket of the type Ariane 5 ECA was launched on 14 May, 2009. During its operation, the telescope was positioned in orbit around the Lagrangian point L2 of the earth-sun system and was named after the discoverer of infrared radiation, Wilhelm Herschel . At the end of April 2013, the end of the mission was declared because the helium required for cooling had been used up. After a series of tests, the satellite was placed in a heliocentric orbit and finally shut down on June 17, 2013.
Planning and commissioning
The project started in 1984 under the name F ar I nfra r ed and S ubmillimetre T elescope ( FIRST ). The budget was around 1.1 billion euros. The main mirror has a diameter of 3.5 meters, which was sintered from twelve segments of silicon carbide at EADS -Astrium in Toulouse . Herschel thus had the largest one-piece mirror that has ever been manufactured for a space telescope. Herschel is therefore the space telescope with the largest mirror and will only be replaced in this capacity by the James Webb Space Telescope (2021 at the earliest), which will, however, consist of a hinged mirror made up of 18 segments. A space telescope with a larger one-piece mirror is not yet planned.
One of the main goals of Herschel was to investigate
- Formation and development of galaxies , especially distant young galaxies, which due to their dust content mainly emit in the far infrared;
- Formation and development of stars , for example through extensive searches for the earliest development phases of stars;
- Physics and chemistry of interstellar matter ;
- Objects in our solar system (comets and planetary atmospheres).
After several postponements, the launch took place on May 14, 2009 at 1:12 p.m. UTC. After the upper stage had closed fire at 13:38 UTC, the Herschel telescope was deployed a few minutes in front of the Planck Space Telescope on a highly elliptical orbit with an apogee height of 1,197,080 km and an orbit inclination to the equator of 6 °. From this orbit it was brought into the envisaged unpowered orbit around the Lagrangian point L2 of the earth-sun system within sixty days . The space telescope was in a 0.8 million kilometer halo orbit around this point, which, however, required occasional small corrections because of its instability. Seen from the sun, this is about 1.5 million kilometers behind the earth.
There are three instruments on board (cameras and spectrometers ) that work in the far infrared and submillimeter range ( terahertz radiation ) of the electromagnetic spectrum at wavelengths between 57 and 670 µm. This area can not be observed from the ground due to the restricted atmospheric window .
The experiments are:
- HIFI (Heterodyne Instrument for Far Infrared): high-resolution spectrometer (157–625 µm) from the Netherlands Institute for Space Research
- PACS (Photodetector Array Camera and Spectrometer): imaging photometer / spectrometer (57–210 µm) from the Max Planck Institute for Extraterrestrial Physics in Garching near Munich
- SPIRE (Spectral and Photometric Image Receiver): imaging photometer / spectrometer (200–670 µm) from the University of Wales in Cardiff
Because of its size, Herschel cannot be completely cooled with liquid helium like earlier infrared space telescopes (e.g. Infrared Astronomical Satellite (IRAS), Infrared Space Observatory (ISO), Spitzer Space Telescope ) . Instead, its actual telescope is shielded from solar radiation with a shield so that it can passively cool down to below 90 Kelvin (−183 ° C) by radiating heat into space . Only the three instruments were cooled with liquid helium, which was sufficient for four years of operation.
On June 19, 2009, ESA published the first photos of the space telescope, which has been in operation since June 14, 2009. They show the spiral galaxy Messier 51, some 37 million light years away . As a result, Herschel expanded knowledge of the formation of stars and also demonstrated storms from molecular gas in distant galaxies.
In January 2013, Herschel allowed a more precise determination of the diameter of the asteroid Apophis .
Herschel's liquid helium, which cools the detectors with its evaporation cold, had almost completely evaporated at the beginning of March 2013. On April 29, the observation mission was declared ended by NASA and ESA because the liquid helium had been completely used up. Due to the lack of cooling, the instruments could no longer continue their observations due to the temperature.
Herschel was withdrawn from his orbit around L2 and sent to a cemetery orbit around the sun. Some tests and measurements were carried out on the telescope until mid-June. Finally, the remaining fuel was used up and then Herschel was shut down for good. A course to the moon with a subsequent controlled crash would also have been possible, but was rejected as too costly. The mission finally ended on June 17, 2013.
|Herschel space telescope||
Infrared Space Observatory (ISO)
(ESA's first infrared satellite)
|Takeoff mass||3402 kg||2498 kg|
|Empty weight approx.||2800 kg||?|
|Cryostat||2367 l of superfluid helium-4 , temp. 1.6 K||2250 l of superfluid helium-4, temp. 1.8 K|
|Active cooling||of certain detectors with helium-3 to 0.3 K||unavailable|
|height||7.5 m||5.3 m|
|Diameter or width||4.0 m||2.3 m|
|Mirror diameter||3.5 m||0.6 m|
|Telescope mass||300 kg||?|
|Duration of use||3 years and 10 months||approx. 2 years and 7 months|
|train||Halo orbit, 0.8 million km around L2 Earth-Sun||Earth orbit 1,038-70,578 km high|
|Launcher||Ariane 5 ECA||Ariane 44P|
|Start date||May 14, 2009||November 19, 1995|
|Mission end||(April 29, 2013 observations) June 17, 2013||May 16, 1998|
|total cost||1.1 billion euros (planned)||?|
- Observation Gives Way To Examination As Herschel Coolant Runs Out. ESA, accessed April 29, 2013 .
- Herschel Completes its 'Cool' Journey in Space. NASA, accessed April 29, 2013 .
- Herschel Ends Operations As Orbiting Testbed. ESA, accessed June 17, 2013 .
- Dietrich Lemke: The Herschel space telescope before the start.
- ESA: Ariane 5 carrying Herschel and Planck lifts off. May 14, 2009, accessed on May 14, 2009 (English).
- Martin Hechler: The orbits of the space telescopes Herschel and Planck
- * ESA Herschel pictures. Retrieved March 5, 2013 .
- http://science.orf.at/science/news/156073 ( page no longer available , search in web archives ) Info: The link was automatically marked as defective. Please check the link according to the instructions and then remove this notice.
- Herschel intercepts asteroid Apophis. January 9, 2013, accessed January 25, 2013 .
- Herschel To Finish Observing Soon. ESA, accessed March 5, 2013 .
- HERSCHEL News. In: smsc.cnes.fr. Retrieved June 12, 2013 .
- European space telescope "Herschel" has had its day . Focus.de. March 5, 2013. Retrieved March 6, 2013.
- Herschel to finish observing soon. ESA, March 5, 2013, accessed April 5, 2013 .
- ISO ( English , PDF ) ESA . P. 4. Archived from the original on October 16, 2006. Retrieved May 15, 2009.
- uppsagd.files.wordpress.com: Data relating to Flight 188 , accessed January 14, 2018
- Stephen Clark: Scientists could aim derelict telescope for moon impact , in Spaceflight now, Date: October 26, 2012, Accessed: October 29, 2012
- ESA: An overview of the Herschel and Planck satellites. Retrieved August 17, 2014 .
- Dietrich Lemke: The Herschel space telescope before the start. in: Stars and Space . Heidelberg 47.2008, No. 1 (Jan.), pp. 36-46.
- Martin Hechler: The orbits of the Herschel and Planck space telescopes. In: Stars and Space. Heidelberg 47.2008, No. 1 (Jan.), pp. 48-55.
- Vincent Minier, et al .: Inventing a Space Mission - The Story of the Herschel Space Observatory. Springer, Cham 2017, ISBN 978-3-319-60023-9 .