Blogarchiv
Astronomie - Cheops, ESA’s exoplanet mission -Update-1

20.12.2019

Liftoff for Cheops, ESA’s exoplanet mission

ESA’s Cheops mission lifted off on a Soyuz-Fregat launcher from Europe’s Spaceport in Kourou, French Guiana, at 09:54:20 CET on 18 December on its exciting mission to characterise planets orbiting stars other than the Sun.

Signals from the spacecraft, received at the mission control centre based at INTA in Torrejón de Ardoz near Madrid, Spain, via the Troll ground tracking station at 12:43 CET confirmed that the launch was successful.

liftoff-for-cheops-pillars
Liftoff for Cheops

Cheops, the Characterising Exoplanet Satellite, is a partnership between ESA and Switzerland, with important contribution from 10 other ESA Member States. ESA’s first mission dedicated to extrasolar planets, or exoplanets, it will investigate known planets beyond our Solar System and provide key insight into the nature of these distant, alien worlds.

Scientists had long speculated about the existence of exoplanets until the discovery of 51 Pegasi b, the first planet found around a Sun-like star, which was announced in 1995. The discoverers, Didier Queloz and Michel Mayor, shared the 2019 Nobel Prize in Physics for their breakthrough finding, which marked the beginning of a new era of investigation and turned exoplanet research into one of the fastest growing areas of astronomy.

Over the past quarter of a century, astronomers using telescopes on Earth and in space have discovered more than 4000 exoplanets around stars near and far, most of which have no counterparts in our Solar System. This widely diverse assortment extends from gassy worlds larger than Jupiter to smaller, rocky planets covered in lava, with the most abundant exoplanet type found in the size range between Earth and Neptune.

Exoplanet imaginarium
Exoplanet imaginarium

“Cheops will take exoplanet science to a whole new level,” says Günther Hasinger, ESA Director of Science.

“After the discovery of thousands of planets, the quest can now turn to characterisation, investigating the physical and chemical properties of many exoplanets and really getting to know what they are made of and how they formed. Cheops will also pave the way for our future exoplanet missions, from the international James Webb Telescope to ESA’s very own Plato and Ariel satellites, keeping European science at the forefront of exoplanet research.”

Cheops will not focus on the search for new planets. Instead, it will follow-up on hundreds of known planets that have been discovered through other methods. The mission will observe these planets exactly as they transit in front of their parent star and block a fraction of its light, to measure their sizes with unprecedented precision and accuracy.

Play
 
$video.data_map.short_description.content
Determining exoplanet sizes with Cheops
Access the video

Cheops measurements of exoplanet sizes will be combined with existing information on their masses to derive the planet density. This is a key quantity to study the internal structure and composition of planets and determine whether they are gaseous like Jupiter or rocky like Earth, whether they are enshrouded in an atmosphere or covered in oceans.

“We are very excited to see the satellite blast off into space,” says Kate Isaak, ESA Cheops project scientist.

“There are so many interesting exoplanets and we will be following up on several hundreds of them, focusing in particular on the smaller planets in the size range between Earth and Neptune. They seem to be the commonly found planets in our Milky Way galaxy, yet we do not know much about them. Cheops will help us reveal the mysteries of these fascinating worlds, and take us one step closer to answering one of the most profound questions we humans ponder: are we alone in the Universe?”

For some planets, Cheops will be able to reveal details about their atmosphere including the presence of clouds and possibly even hints of the cloud composition. The mission also has the capability to discover previously unknown planets by measuring tiny variations in the timing of the transit of a known planet, and can also be used to search for moons or rings around some planets.  

Cheops is the first ‘Small’-class mission implemented in the Cosmic Vision 2015–25 programme, the current planning cycle for ESA's space science missions, and the first mission in the programme overall to be launched. As a Small-class mission with a relatively short time – only five years –  from project start to launch, it entailed several challenges, making it necessary to use technologies that have already been tried and tested in space, and driving several aspects of the satellite design.

Play
 
$video.data_map.short_description.content
Cheops observing in space
Access the video

“Both Cheops instrument and spacecraft are built to be extremely stable, so as to measure the incredibly small variations in the light of distant stars as their planets transit in front of them,” says Nicola Rando, ESA Cheops project manager.

“For a planet like Earth, this amounts to the equivalent of watching the Sun from a distant star and measuring its light dim by a tiny fraction of a percent.

“Now we are looking forward to the first part of the operational activities, making sure that the satellite and instrument perform as expected, ready for scientists to perform their world-class science.”

Cheops shared the ride into space with the Italian space agency ASI’s Cosmo-SkyMed Second Generation satellite, which separated 23 minutes after liftoff.

Update

Cheops, ESA’s first exoplanet mission
Cheops, ESA’s first exoplanet mission

More information about Cheops
Cheops is an ESA mission implemented in partnership with Switzerland, with important contributions from Austria, Belgium, France, Germany, Hungary, Italy, Portugal, Spain, Sweden, and the United Kingdom.

ESA is the Cheops mission architect, responsible for procurement and testing of the satellite, launch, the launch and early operations phase, in-orbit commissioning, as well as the Guest Observers’ Programme. The prime contractor for the design and construction of the spacecraft is Airbus Defence and Space in Spain. The consortium of 11 ESA Member States led by Switzerland provided essential elements of the mission.

Cheops is a Small, or S-class, mission in ESA’s science programme. S-class missions have a much smaller budget than Large- and Medium-class missions, and a much shorter time from project start to launch. These conditions have made it necessary to use technologies that have already been tried and tested in space, and a number of tasks traditionally undertaken by ESA, such as operations, will be done by the Consortium. The Cheops mission consortium runs the Mission Operations Centre located at INTA, in Torrejón de Ardoz, Spain, and the Science Operations Centre, located at the University of Geneva, Switzerland.

Eighty percent of the science observing time on Cheops is dedicated to the Guaranteed Time Observing programme, defined by the Cheops Science Team. The remaining 20% is made available to the astronomical community in the form of an ESA-run Guest Observers' programme, with proposals selected via a competitive peer-review selection process. 

Quelle: ESA

----

Update: 28.03.2020

.

Airbus completes In Orbit Commissioning of CHEOPS

cheops-characterising-exoplanet-satellite-orbit-artwork-hg

CHEOPS marks the first time that Airbus in Spain has been the prime contractor for the whole mission, from satellite development, through launch, to LEOP and IOC. The entire mission development was completed in record time without delays and met the very tight budget. To do this, Airbus managed a team of 24 companies from 11 European countries, seven of them Spanish, confirming Airbus as the driving force behind the space industry in Spain.

Airbus has received confirmation from ESA of a successful end to the In Orbit Commissioning (IOC) of CHEOPS after the IOC review yesterday. This critical phase was performed by Airbus in Spain with the support of the Instrument Team (University of Bern), Mission Operation Centre (INTA), Science Operation Centre (University of Geneva) and ESA.

The IOC phase started on 7th January and over the past two and a half months Airbus has conducted the operations to verify the performance of the satellite (platform and instrument), the ground segment and the science package. During this time the main goal was to consolidate the documentation, processes and procedures for use during the operational phase.

ESA recognised the great job done by the Airbus teams and stated there were no issues preventing routine operations from starting and confirmed hand-over of the mission operations from Airbus to INTA and the mission consortium.

Fernando Varela, Head of Space Systems in Spain, said: "The in-orbit delivery of the CHEOPS satellite is the culmination of the Airbus participation in the programme. It is the first European exoplanetary mission and the first ESA mission built by Airbus in Spain. The professionalism of the technical and engineering teams at Airbus was key to this success."

CHEOPS will be controlled by INTA and the mission consortium (University of Geneva and University of Bern). Nevertheless, Airbus is also ready to assist during the operational phase for the whole mission life.

CHEOPS marks the first time that Airbus in Spain has been the prime contractor for the whole mission, from satellite development, through launch, to LEOP and IOC. The entire mission development was completed in record time without delays and met the very tight budget. To do this, Airbus managed a team of 24 companies from 11 European countries, seven of them Spanish, confirming Airbus as the driving force behind the space industry in Spain.

As a reminder, CHEOPS is the first in ESA's FAST TRACK missions programme whose main characteristics are low cost and a challenging budget. CHEOPS will characterise exoplanets orbiting nearby stars, observing known planets in the size range between Earth and Neptune and precisely measuring their radii to determine their density and understand what they are made of.

Quelle: SD

----

Update: 18.04.2020

.

CHEOPS space telescope ready for scientific operation

CHEOPS has reached its next milestone: Following extensive tests in Earth's orbit, some of which the mission team was forced to carry out from home due to the coronavirus crisis, the space telescope has been declared ready for science. CHEOPS stands for “CHaracterising ExOPlanet Satellite”, and has the purpose of investigating known exoplanets to determine, among other things, whether they have conditions that are hospitable to life.

CHEOPS is a joint mission by the European Space Agency (ESA) and Switzerland, under the leadership of the University of Bern in collaboration with the University of Geneva (UNIGE). After almost three months of extensive testing, with part of it in the midst of the lockdown to contain the coronavirus, on Wednesday, March 25, 2020, ESA declared the CHEOPS space telescope ready for science. With this achievement, ESA has handed over the responsibility to operate CHEOPS to the mission consortium, which consists of scientists and engineers from approximately 30 institutions in 11 European countries.

Successful completion of the CHEOPS test phase despite the coronavirus crisis

The successful completion of the test phase took place in very challenging times, with essentially all the mission team being required to work from home towards the end of the phase. “The completion of the test phase was only possible with the full commitment of all the participants, and because the mission has an operational control system that is largely automated, allowing commands to be sent and data to be received from home,” explains Willy Benz, Professor of Astrophysics at the University of Bern and Principal Investigator of the CHEOPS mission.

A team of scientists, engineers and technicians put CHEOPS through a period of extensive testing and calibration from the beginning of January until the end of March. “We were thrilled when we realized that all the systems worked as expected or even better than expected,” explains CHEOPS Instrument Scientist Andrea Fortier from the Univerisity of Bern, who led the commissioning team of the consortium.

Meeting high requirements on measuring accuracy

The team began by focusing on the evaluation of the photometric performance of the space telescope. CHEOPS has been conceptualized as a device of exceptional precision capable of detecting exoplanets the size of planet Earth. “The most critical test was in the precise measurement of the brightness of a star to a variance of 0.002% (20 parts-per-million),” explains Willy Benz. This precision is required so as to clearly recognize the dimming caused by the passage of an Earth-sized planet in front of a Sun-like star (an event known as a “transit”, which can last several hours). CHEOPS was also required to demonstrate its ability to maintain this degree of precision for up to two days.

CHEOPS surpasses the requirements

To verify this, the team focused on a star known as HD 88111. The star is located in the Hydra constellation, some 175 light years away from Earth, and it is not known to host planets. CHEOPS took an image of the star every 30 seconds for 47 consecutive hours (see Figure 1). Every image was carefully analyzed, initially using a specialized automatic software package, and subsequently by the team members, to determine in each image the brightness of the star as accurately as possible. The team had expected the brightness of the star to change during the period of observation due to a variety of effects, such as other stars in the field of view, the tiny jitter motion of the satellite, or the impact of cosmic ray hits on the detector.

The results of the 5,640 photos taken by CHEOPS over 47 hours are shown in Figure 2 as a “light curve”. The curve depicts the change over time in the brightness measurements from all the images, showing a root-mean-square scatter of 0.0015% (15 parts-per-million). “The light curve measured by CHEOPS was pleasingly flat. The space telescope easily surpasses the requirement for being able to measure brightness to a precision of 0.002% (20 parts-per-million),” explains Christopher Broeg, Mission Manager for the CHEOPS mission at the University of Bern.

An exoplanet that would float

The team observed other stars, including some known to host planets (these are called exoplanets). CHEOPS focused on the planetary system HD 93396 which is in the Sextans constellation, some 320 light years away from Earth. This system consists of a giant exoplanet called KELT-11b, which was discovered in 2016 to orbit this star in 4.7 days. The star is almost three times the size of the sun.

The team chose this particular system because the star is so big that the planet takes a long time to pass in front of it: in fact, almost eight hours. “This gave CHEOPS the opportunity to demonstrate its ability to capture long transit events otherwise difficult to observe from the ground, as the ‘astronomical’ part of the night for ground-based astronomy usually takes less than eight hours,” explains Didier Queloz, professor at the Astronomy Department of the Faculty of Science at the University of Geneva and spokesperson of the CHEOPS Science Team. The first transit light curve of CHEOPS is shown in Figure 3, where the dip due to the planet occurs approximately nine hours after the he beginning of the observation.

The transit of KELT-11b measured by CHEOPS enabled determining the size of the exoplanet. It has a diameter of 181,600 km, which CHEOPS is able to measure with an accuracy of 4'290 km. The diameter of the Earth, in comparison, is only approximately 12,700 km, while that of Jupiter – the biggest planet in our solar system – is 139,900 km. Exoplanet KELT-11b is therefore bigger than Jupiter, but its mass is five times lower, which means it has an extremely low density: “It would float on water in a big-enough swimming pool,” says David Ehrenreich, CHEOPS Mission Scientist from the University of Geneva. The limited density is attributed to the close proximity of the planet to its star. Figure 4 shows a drawing of the first transit planet system to be successfully observed by CHEOPS.

Benz explains that the measurements by CHEOPS are five times more accurate than those from Earth. “That gives us a foretaste for what we can achieve with CHEOPS over the months and years to come,” continues Benz.

CHEOPS – in search of potential habitable planets

The CHEOPS mission (CHaracterising ExOPlanet Satellite) is the first of the newly created “S-class missions” of ESA (small class missions with an ESA budget of less than 50 million), and is dedicated to characterizing the transits of exoplanets. CHEOPS measures the changes in the brightness of a star when a planet passes in front of that star. This measured value allows the size of the planet to be derived, and for its density to be determined on the basis of existing data. This provides important information on these planets – for example, whether they are predominantly rocky, are composed of gases, or if they have deep oceans. This, in turn, is an important step in determining whether a planet has conditions that are hospitable to life.

CHEOPS was developed as part of a partnership between the European Space Agency (ESA) and Switzerland. Under the leadership of the University of Bern and ESA, a consortium of more than a hundred scientists and engineers from eleven European states was involved in constructing the satellite over five years.

CHEOPS began its journey into space on Wednesday, December 18, 2019 on board a Soyuz Fregat rocket from the European spaceport in Kourou, French Guiana. Since then, it has been orbiting the Earth on a polar orbit in roughly an hour and a half at an altitude of 700 kilometers following the terminator.

The Swiss Confederation participates in the CHEOPS telescope within the PRODEX programme (PROgramme de Développement d'EXpériences scientifiques) of the European Space Agency ESA. Through this programme, national contributions for science missions can be developed and built by project teams from research and industry. This transfer of knowledge and technology between science and industry ultimately also gives Switzerland a structural competitive advantage as a business location – and enables technologies, processes and products to flow into other markets and thus generate added value for our economy.

More information: https://cheops.unibe.ch/de/

Bernese space exploration: With the world’s elite since the first moon landing

When the second man, "Buzz" Aldrin, stepped out of the lunar module on July 21, 1969, the first task he did was to set up the Bernese Solar Wind Composition experiment (SWC) also known as the “solar wind sail” by planting it in the ground of the moon, even before the American flag. This experiment, which was planned and the results analysed by Prof. Dr. Johannes Geiss and his team from the Physics Institute of the University of Bern, was the first great highlight in the history of Bernese space exploration.

Ever since Bernese space exploration has been among the world’s elite. The numbers are impressive: 25 times were instruments flown into the upper atmosphere and ionosphere using rockets (1967-1993), 9 times into the stratosphere with balloon flights (1991-2008), over 30 instruments were flown on space probes, and with CHEOPS the University of Bern shares responsibility with ESA for a whole mission.

The successful work of the Department of Space Research and Planetary Sciences (WP) from the Physics Institute of the University of Bern was consolidated by the foundation of a university competence center, the Center for Space and Habitability (CSH). The Swiss National Fund also awarded the University of Bern the National Center of Competence in Research (NCCR) PlanetS, which it manages together with the University of Geneva.

Exoplanet research in Geneva: 24 years of expertise awarded a Nobel Prize

CHEOPS will provide crucial information on the size, shape, formation and evolution of known exoplanets. The installation of the "Science Operation Center" of the CHEOPS mission in Geneva, under the supervision of two professors from the UniGE Astronomy Department, is a logical continuation of the history of research in the field of exoplanets, since it is here that the first was discovered in 1995 by Michel Mayor and Didier Queloz, winners of the 2019 Nobel Prize in Physics. This discovery has enabled the Astronomy Department of the University of Geneva to be at the forefront of research in the field, with the construction and installation of HARPS on the ESO's 3.6m telescope at La Silla in 2003, a spectrograph that remained the most efficient in the world for two decades to determine the mass of exoplanets. However, this year HARPS was surpassed by ESPRESSO, another spectrograph built in Geneva and installed on the VLT in Paranal.

CHEOPS is therefore the result of two national expertises, on the one hand the space know-how of the University of Bern with the collaboration of its Geneva counterpart and on the other hand the ground experience of the University of Geneva supported by its colleague in the Swiss capital. Two scientific and technical competences that have also made it possible to create the National Center of Competence in Research (NCCR) PlanetS.

Quelle:  University of Bern

 

1825 Views