2023-06-30 09:49:46
The war in Ukraine initiated by Russia and its unilateral decision not to allow its Soyuz rockets to be launched from the European Spaceport, in French Guiana, forced those responsible for the Euclid mission to find a launcher and alternate takeoff site.
Therefore, this Saturday, July 1, at 5:11 p.m. (Spanish peninsular time) will take off aboard a rocket Falcon 9 de SpaceX from Cape Canaveral, Florida (USA). This is how the European Space Agency (ESA) who leads the project, leaving July 2 as a reservation date in case any incident arises. Some twenty European countries, including Spain, are taking part in the mission.
Recently several Euclid scientists at ESA explained at the European Center for Space Astronomy (ESAC), near Madrid, the details of the mission. Guadalupe Canas, a postdoctoral researcher in cosmology, noted three main goals. On the one hand, “we are going to map the universe, and we will do it with a 3D map of what is known as the large-scale structure of the universe, showing the distribution of matter in space through time.”
We are going to map the universe, and we will do it with a 3D map of the large-scale structure of the universe, showing the distribution of matter in space through time.
Guadalupe Cañas (ESA)
“We do this with another very clear objective: to test the current model that explains astrophysical observations: the standard cosmological model Lamda-CDM (by cold dark matterin English), which tells us that the major components of the universe are fundamentally two: a 70% dark energy and a 25% dark matterAnd we don’t know what they are.” Investigating the nature of both is the third objective.
Study two effects in the universe
To discern where the matter is located in the universe, both the dark and the ordinary or baryonic (of which we, the planets, stars, galaxies, etc., are formed), the so-called weak gravitational lensing effect: the light we see from distant galaxies reaches us distorted. This effect will be measured statistically by observing millions of galaxies up to a distance of 10 billion light years in more than a third of the sky.
Euclid will observe millions of galaxies up to a distance of 10 billion light years
“A second aspect that we will measure is how galaxies are positioned in the universe. They do not do it randomly, but following a pattern of baryon acoustic oscillationsdetermined by information we already know, such as observations of the microwave cosmic backgroundwhich we have studied with the ESA Planck mission”, clarified Cañas.
“These baryonic acoustic oscillations, together with the weak gravitational lensing effect, are the primary Euclid proofs that will serve us to verify if the standard cosmological model is what it is or we can find a better one”, he added.
Schematic of the weak gravitational lensing effect and the baryon acoustic oscillations that Euclid will observe. / THAT
Two instruments: VIS and NISP
For his part, Xavier Dupac, Euclid operations scientist, detailed the two instruments that the telescope will carry to carry out these investigations: “VIS, which operates in the visible range, with exquisite resolution, to observe all galaxies; and NISPa near-infrared photometer and spectrometer to see how they clump together and analyze their distance by their redshift (greater as they get further away)”.
Dupac recalled that the observable universe contains 400 billion galaxies, “and Euclid will observe about a billion over the course of six years of observations (plus a possible extension of four others), operating from a stable gravitational point called Lagrangian point L2 of the Earth Moon system.
Observe a third of the sky
Observations will be made in a 35% of the whole sky, since in the rest it is made difficult by the presence of the Milky Way and the zodiacal light (with interplanetary dust). Within the selected field, the sections that will be studied each year are planned, until the final map is completed.
Area of the sky that Euclid will observe over six years (the phases are colored with different colors). /ESA/Euclid Consortium
Regarding the characteristics of the space telescope, Euclid’s science operations coordinator, William Buenadichaoffered some data: “it weighs of tons and measure almost 5 m tall”.
Its configuration is classic, with a solar panel that is used to obtain energy and, at the same time, thermally protect the ship from the Sun. telescope and its of the instruments scientists (VIS and NISP), has a service module with electrical distribution, attitude control, propulsion, remote control, telemetry and data processing.
This information will be sent during a 4-hour daily pass, and among the ground stations that will receive it is ESA’s Cebreros, in Ávila. “The raw data will be processed by the Euclid consortium, an international group in which more than 2,000 people collaborate, who will deliver data products (images, spectra, measurements, catalogs, among others). These, in turn, we will make available from ESAC to the entire scientific community”, pointed out the coordinator.
mission challenges
As he commented, one of the challenges of the mission will be precisely manage large volumes of data: 170 petabytes in the processing, to deliver some 20 petabytes of scientific information until 2031. Other challenges will be to obtain the complete stability of the ship and the aiming precision: 25 milliarcseconds for 700 seconds.
The international consortium Euclid, with more than 2,000 people, will work on the complex data processing
“It’s like taking a €2 coin, taking it a kilometer away and precisely aiming a laser beam for more than 700 seconds, floating in space,” Buenadicha compared.
The operations coordinator also explained the phases after the launch: one of commissioner one month for positioning in the definitive orbit, turning on all the systems and focusing the telescope; another of performance and characterization for two months, to test all the devices, and another couple of months to calibrations and confirm stability telescope to different thermal environments.
Then the scanning of the sky will begin during the six years of operation to learn new facts about our universe and the enigmatic dark matter and energy.
European industry with Spanish participation in Euclid
The Euclid space telescope has been manufactured by an industrial consortium led by Thales Alenia Space Italiatogether with the main subcontractor Airbus in charge of the payload, who have had a budget of €450 million. Spain has participated with 10% of the value of the contract.
“More than 80 companies (of which eight are Spanish) contribute from 20 European countries and with more than 140 contracts,” explained a representative of Thales Alenia Space, Susana Infanteproject manager of the Euclid communication subsystem, “which will download more than 150,000 images, something very complex to do 1.5 million km from Earth.”
The engineer highlighted that the technological jewel of the mission is a high-gain antenna (in the so-called K band and with a three-axis mechanism), in addition to mentioning the role of the Spanish companies that participate in Euclid:
Airbus D&S Spain: structure and subsystem of thermal control of the service module, radiator wiring of the payload module.
Alter Technology: sourcing coordination for ESA.
Crisis: fine guiding sensor electronic unit.
Deimos space: attitude control subsystem simulation software.
GTD: elements of the application software.
Navair: manufacture of part of the wiring of the service module.
Tendons: antenna pointing mechanism that goes in the communication system, in addition to the mechanisms of a mirror and responsible for the attitude control subsystem. Plus two low gain antennas.
Thales Alenia Space: responsible for the communication subsystem.
In addition to industry, various Spanish research centers participate in the mission. The Institute of Space Sciences (ICE-CSIC), together with the Institute of Space Studies of Catalonia (IEC) and the Institute of High Energy Physics (IFAE), have developed the filter wheel of the NISP instrument.
The person responsible for the design, construction and validation of the control electronics of this instrument has been the Polytechnic University of Cartagena (UPCT), in collaboration with the Instituto de Astrofísica de Canarias (IAC). He also leads several programs to investigate the properties of dark matter, the formation and evolution of galaxies, and the identification of substellar mass objects with Euclid data.
On the other hand, the ICE-CSIC and the Port of Scientific Information (PIC), a center managed by the IFAE and by the Center for Energy, Environmental and Technological Research (VILLAGE), have been responsible for the mission’s cosmological simulations. In addition, the PIC is the mission’s scientific data center in Spain.
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