CHEOPS (space telescope)

CHEOPS
Type:	Space telescope
Operator:	ESA
COSPAR-ID :	2019-092B
Mission dates
Dimensions:	290 kg
Size:	2.6 m high
Begin:	December 18, 2019, 08:54:20 UTC
Starting place:	Center Spatial Guyanais
Launcher:	Soyuz-ST-B / Fregat
Flight duration:	3.5 years
Status:	in orbit
Orbit data
Rotation time :	98.8 minutes
Orbit inclination :	98.2 °
Apogee height :	approx. 710 km
Perigee height :	approx. 700 km

CHEOPS (for CH aracterising E x OP lanet S atellite) is a space telescope of the European Space Agency (ESA) with the mission objective, Exoplaneten in the vicinity of the earth to characterize and analyze. It will observe around 400 stars with known planetary systems from an earth orbit .

The satellite is the first of a possible series of so-called S-Class missions that are to be implemented within a comparatively short time (of 4 years) and with a limited budget. As the ESA announced on October 19, 2012, the mission was selected from a total of 26 proposals that had been requested in the spring of that year. The main partner of ESA is Switzerland , with additional contributions from ten other countries. The satellite bus is based on the AstroBus from Airbus . On December 18, 2019, a Soyuz rocket was launched into space with the telescope on board.

aims

CHEOPS is to investigate bright, but less active stars with already detected exoplanets between Super-Earth and Neptune using ultra-precise photometry . The observed objects were found before the mission, e.g. B. by the RV method or ground based transit searches such as NGTS . It is expected that NGTS will find approximately 50 targets less than six Earth radii in diameter for the mission. These stars are bright enough to later enable measurements of radial velocities with the required precision. For stars with a magnitude of V <9, the system should achieve a photometric accuracy of 20 ppm for 6 hour time scales and 85 ppm over 3 hours for a magnitude V <12. In contrast to previous transit (search) missions, CHEOPS is not primarily based on further Search for exoplanets, but examine known exoplanets more closely. The satellite concentrates on the brightest stars, where both precise planetary masses (RV method) and CHEOPS planetary radii can be determined with an accuracy of 10%. The density can be calculated from the mass and diameter, which in turn enables conclusions to be drawn about the nature of the exoplanet. In this way it can be determined whether the planet consists predominantly of rock, ice or gas. In this way, CHEOPS can also help with the selection of planets to be observed, which will later be examined more closely using expensive large telescopes such as the JWST or the ELT .

technology

CHEOPS is to observe the expected passages of exoplanets in front of their central star by means of high-precision brightness measurements with a telescope with a 32 cm aperture and 1.2 m length ( transit method ) and from this determine their sizes , masses and possible atmospheres . This opening is much larger than that of the telescopes such as TESS or Kepler , which were designed to search for extrasolar worlds and not to investigate them. To ensure that the image of the star covers as many of its CCD pixels as possible and the examination is as precise as possible, the telescope is fuzzy during its examinations.

The satellite, which weighs around 290 kg, is brought into a 700 km high sun-synchronous orbit (SSE). CHEOPS will transmit the scientific data as well as telemetry and control in the S-band. The telescope and especially the radiators, which cool the electronics, are protected from the sun's heat by solar panels and a small sun shield when in space . The service life of the satellite is said to be 3.5 years, the launch was scheduled for December 17, 2019 with a Soyuz rocket , but had to be canceled at short notice. The Soyuz rocket with the space telescope was launched on December 18, 2019.

history

In 2008 Willy Benz and Didier Queloz planned a feasibility study for a small satellite as a new research focus for the Swiss National Science Foundation . The feasibility study was carried out in 2010 without the National Fund, but with the help of other partners. The project seemed to have died as a result, as a space project worth 100 million francs was too expensive for Switzerland alone. In spring 2012, ESA, which had previously only supported larger missions, announced a mission of this class for the first time. The Bernese astronomers then formed a consortium of 11 nations. Switzerland contributed 33 million francs and its industry built the structure of the satellite. The optics come from Italy, the electronics from Germany. In October 2019, after tests, the satellite was brought to the European Spaceport , from where it was finally launched on December 18, 2019.

Mission history since launch

After the start in December 2019, the first tests were carried out at the beginning of 2020. Among other things, well-known stars were observed to test the performance of the instruments in orbit. The first target was the star HD 70843. The image from HD 70843 showed the expected and desired distortion and represented an important intermediate step in the preparation of the scientific mission. Another important goal was to show that the brightness measurement of a star with a variance of only 0.002% can be carried out. For this purpose, the star HD 88111 was observed, of which no exoplanets are known to date. The signal showed a variance of 0.0015% and was therefore able to meet the high expectations. The next step was to carry out first planetary observations using the transit method. A first success was achieved in spring 2020 when the planet KELT-11b was observed around the star HD 93396. This planet orbits its parent star in just 4.7 days. With the help of the data from CHEOPS, the diameter of the planet could be determined to be 181,600 ± 4,300 km . This measurement was 5 times more precise than previous ground-based measurements. Therefore, the scientific mission could start as planned. Her first targets include a selection of stars and their known exoplanets, including at 55 Cancri and Gliese 436 .

public relation

Between March and October 2015, the ESA organized a competition in which children could submit drawings on the subject of space or CHEOPS. Out of over 8000 drawings, 2748 were drawn, which were reduced a thousand times and engraved on two titanium plates at the Bern University of Applied Sciences in Burgdorf using a laser and launched into space with CHEOPS.

Web links

Commons : CHEOPS  - collection of images, videos and audio files

• CHEOPS project website of the University of Bern
• CHEOPS mission progression and status of the University of Bern
• ESA: CHEOPS (CHaracterizing ExOPlanets Satellite) (English)
• Cheops targets exoplanets . Astronews announcement from October 2012

Individual evidence

1. ↑ ^{a b c} CHEOPS (Characterizing ExOPlanets Satellite). In: eoPortal.org. ESA , accessed April 7, 2017 . 
2. ↑ ^{a b c} Launch Schedule. In: SpaceflightNow.com. Retrieved December 17, 2019 . 
3. ↑ ^{a b} Alois Feusi: The planet scout Cheops remains on the ground for the time being. In: nzz.ch. Neue Zürcher Zeitung , December 17, 2019, accessed on December 17, 2019 . 
4. ↑ Ciprian Sufitchi: Cheops. December 29, 2019, accessed on August 29, 2019 . 
5. ↑ ^{a b} Exoplanet mission gets ticket to ride. In: esa.int. ESA, April 6, 2017, accessed December 17, 2019 . 
6. ↑ ^{a b c} Alexander forehead: New space telescope. Surveying the Exoplanets. In: Spektrum.de . December 18, 2019, accessed December 30, 2019 . 
7. ↑ ESA Science Program's new small satellite will study super-Earths. In: esa.int. ESA, October 19, 2012, accessed December 17, 2019 . 
8. ↑ Alois Feusi: «Cheops» is ready to explore foreign worlds. In: nzz.ch. Neue Zürcher Zeitung, August 28, 2018, accessed on December 17, 2019 . 
9. ^ "Cheops" mission started. Deutschlandfunk.de, December 18, 2019.
10. ^ Tilmann Althaus: Exoplanets. Explore distant worlds with Cheops. In: Spektrum.de. October 24, 2012, accessed December 17, 2019 . 
11. ↑ CHEOPS - Characterizing ExOPlanet Satellite. In: sci.esa.int. European Space Agency, accessed December 17, 2019 . 
12. ↑ This Swiss satellite helps in the search for extraterrestrial life. In: TagesAnzeiger.ch. December 5, 2019, accessed December 17, 2019 . 
13. ↑ ^{a b c} Cheops observes its first exoplanets and is ready for science. ESA , April 16, 2020, accessed on July 24, 2020 . 
14. ^ Cheops image of its first target star. ESA , February 7, 2020, accessed on July 24, 2020 . 
15. ↑ CHEOPS space telescope is ready for scientific operations. University of Bern , April 16, 2020, accessed on July 24, 2020 . 
16. ↑ CHEOPS children's drawing campaign. In: cheops.unibe.ch. University of Bern, accessed on December 17, 2019 . 
17. ↑ CHEOPS children's drawings are engraved. In: cheops.unibe.ch. University of Bern, accessed on December 17, 2019 .