16.08.2021
DART Gets Its Wings: Spacecraft Integrated with Innovative Solar Array Technology and Camera
The recently installed Roll-Out Solar Arrays (ROSA) and Didymos Reconnaissance and Asteroid Camera for Optical (DRACO) navigation are two critical technologies that will enable the DART spacecraft to navigate through space and effectively reach the Didymos asteroid system.
Perched atop a stand in the middle of a high-ceilinged clean room, DART is beginning to look like the intrepid spacecraft that will aim itself directly into an asteroid next fall. With the addition of its compact Roll-Out Solar Arrays (ROSA) coiled into two gold cylinders that flank the sides of the spacecraft, and its less visible but still integral imager, the Didymos Reconnaissance and Asteroid Camera for Optical (DRACO) navigation tucked safely beneath its panels, the spacecraft is close to fully integrated.
This mix of current and new technologies, some of which it will demonstrate for the first time, will see DART through its 10-month journey toward its asteroid target.
NASA's DART, the Double Asteroid Redirection Test, is a carefully planned demonstration that will help determine if kinetic impactor technology-flying a spacecraft directly into a small Solar System body at speeds of about 15,000 miles per hour with the intention of changing its course-can serve as a reliable method of asteroid deflection in the event that such a hazard ever heads for the Earth. NASA is constantly monitoring the skies and has already identified nearly 40% of potentially hazardous asteroids larger than 140 meters (459 feet) in size, none of which are slated to impact our planet, including the binary system selected for this first-ever deflection test.
But to prove that our planet can expect the unexpected, the DART mission will set out to push an asteroid and safely change its motion in space. For the last two years, the spacecraft destined for this undertaking has been developed and built at the Johns Hopkins Applied Physics Laboratory (APL) in Laurel, Maryland. APL, which leads the mission for NASA, is now putting the finishing touches on the spacecraft.
The recently installed ROSA and DRACO are two critical technologies that will enable the spacecraft to navigate through space and reach the Didymos asteroid system. The flexible and rollable modular "wings" are lighter, more compact and stiffer than traditional solar arrays despite their size; in space, each array will slowly unfurl to reach 28 feet in length-about the size of a bus.
The technology was first successfully tested in 2017 on the International Space Station (ISS), and newer versions were installed this past June for full-time use on the ISS. DART will be the first spacecraft to fly the new arrays, paving the way for their use on future missions. Redwire developed the technology at their Goleta, California facility and delivered ROSA to APL in May and worked closely with the APL team in the following weeks to carefully install them onto the spacecraft.
And while DRACO is not entirely "new" (it was inspired by the New Horizons LORRI camera), this upgraded imager will be the sole instrument onboard the spacecraft. Combined with the autonomous navigation software SMART Nav (Small-body Maneuvering Autonomous Real-Time Navigation), it will play the key role in helping DART navigate through space and identify the correct asteroid to aim itself toward.
"Traditional navigation techniques would only get DART somewhere within about 9 miles of the target asteroid," said APL's Zach Fletcher, DRACO lead engineer. "To achieve our mission objectives, we need to remove the rest of that error via on-board optical navigation. DRACO starts supplying images to DART's on-board autonomous navigation system more than 50,000 miles from its target, four hours before the impact and is key to DART achieving a kinetic impact on Dimorphos."
The images DRACO returns of the target asteroid Dimorphos, including the last-second glimpse of its own impact site on the asteroid, will be crucial toward analyzing the results of the DART test and understanding how the asteroid was affected.
DART has been through its paces in the last several months, enduring a battery of environmental testing and analysis as the final pieces of the craft started coming together. Likewise, the SMART Nav software has seen its fair share of testing so the team can confidently relinquish the reins on DART in the final hours before it collides into Dimorphos. With DRACO and ROSA on board, the DART spacecraft completed vibration testing in late July to ensure that all of its hardware is secure and ready for the rigors of launch.
The Light Italian CubeSat for Imaging of Asteroids, or LICIACube, contributed by the Italian Space Agency, will be one of the final components to hitch a ride on DART before it is delivered to the launch site this October. LICIACube will deploy roughly five days prior to the DART impact and capture images of the spacecraft's final moments, the resulting ejecta plume, and the back side of the asteroid that DRACO will never see.
"DART is the result of years of work by a dedicated team and partners who have overcome unique challenges to accomplish firsts in both technology development and planetary defense," said DART mechanical engineer Betsy Congdon, who led the team during the installation. "With the successful installation and testing of two critical technologies, DRACO and ROSA, we're very confident that DART is ready to complete its final system testing and reviews before shipping to the launch site."
This November, the spacecraft will launch on a SpaceX Falcon 9 rocket from Vandenberg Space Force Base near Lompoc, California. In the fall of 2022, DART will have its sights set for Dimorphos, the smaller moonlet orbiting the larger Didymos asteroid.
Its collision with Dimorphos will change the speed of the moonlet's orbit around the main body by several minutes. And despite being approximately 6.8 million miles away from Earth at the time of impact, the asteroid system will be visible to ground-based telescopes, which scientists will use to determine the exact change in the orbital period.
DART is directed by NASA's Planetary Defense Coordination Office to APL with support from several NASA centers: the Jet Propulsion Laboratory, Goddard Space Flight Center, Johnson Space Center, Glenn Research Center and Langley Research Center.
Quelle: SD
+++
Perched atop a stand in the middle of a high-ceilinged clean room, DART is beginning to look like the intrepid spacecraft that will aim itself directly into an asteroid next fall. With the addition of its compact Roll-Out Solar Arrays (ROSA) coiled into two gold cylinders that flank the sides of the spacecraft, and its less visible but still integral imager, the Didymos Reconnaissance and Asteroid Camera for Optical (DRACO) navigation tucked safely beneath its panels, the spacecraft is close to fully integrated.
This mix of current and new technologies, some of which it will demonstrate for the first time, will see DART through its 10-month journey toward its asteroid target.
NASA's DART, the Double Asteroid Redirection Test, is a carefully planned demonstration that will help determine if kinetic impactor technology—flying a spacecraft directly into a small Solar System body at speeds of about 15,000 miles per hour with the intention of changing its course—can serve as a reliable method of asteroid deflection in the event that such a hazard ever heads for the Earth. NASA is constantly monitoring the skies and has already identified nearly 40% of potentially hazardous asteroids larger than 140 meters (459 feet) in size, none of which are slated to impact our planet, including the binary system selected for this first-ever deflection test.
But to prove that our planet can expect the unexpected, the DART mission will set out to push an asteroid and safely change its motion in space. For the last two years, the spacecraft destined for this undertaking has been developed and built at the Johns Hopkins Applied Physics Laboratory (APL) in Laurel, Maryland. APL, which leads the mission for NASA, is now putting the finishing touches on the spacecraft.
The recently installed ROSA and DRACO are two critical technologies that will enable the spacecraft to navigate through space and reach the Didymos asteroid system. The flexible and rollable modular “wings” are lighter, more compact and stiffer than traditional solar arrays despite their size; in space, each array will slowly unfurl to reach 28 feet in length—about the size of a bus. The technology was first successfully tested in 2017 on the International Space Station (ISS), and newer versions were installed this past June for full-time use on the ISS. DART will be the first spacecraft to fly the new arrays, paving the way for their use on future missions. Redwire developed the technology at their Goleta, California facility and delivered ROSA to APL in May and worked closely with the APL team in the following weeks to carefully install them onto the spacecraft.
And while DRACO is not entirely “new" (it was inspired by the New Horizons LORRI camera), this upgraded imager will be the sole instrument onboard the spacecraft. Combined with the autonomous navigation software SMART Nav (Small-body Maneuvering Autonomous Real-Time Navigation), it will play the key role in helping DART navigate through space and identify the correct asteroid to aim itself toward.
“Traditional navigation techniques would only get DART somewhere within about 9 miles of the target asteroid,” said APL’s Zach Fletcher, DRACO lead engineer. “To achieve our mission objectives, we need to remove the rest of that error via on-board optical navigation. DRACO starts supplying images to DART's on-board autonomous navigation system more than 50,000 miles from its target, four hours before the impact and is key to DART achieving a kinetic impact on Dimorphos."
The images DRACO returns of the target asteroid Dimorphos, including the last-second glimpse of its own impact site on the asteroid, will be crucial toward analyzing the results of the DART test and understanding how the asteroid was affected.
DART has been through its paces in the last several months, enduring a battery of environmental testing and analysis as the final pieces of the craft started coming together. Likewise, the SMART Nav software has seen its fair share of testing so the team can confidently relinquish the reins on DART in the final hours before it collides into Dimorphos. With DRACO and ROSA on board, the DART spacecraft completed vibration testing in late July to ensure that all of its hardware is secure and ready for the rigors of launch.
The Light Italian CubeSat for Imaging of Asteroids, or LICIACube, contributed by the Italian Space Agency, will be one of the final components to hitch a ride on DART before it is delivered to the launch site this October. LICIACube will deploy roughly five days prior to the DART impact and capture images of the spacecraft's final moments, the resulting ejecta plume, and the back side of the asteroid that DRACO will never see.
"DART is the result of years of work by a dedicated team and partners who have overcome unique challenges to accomplish firsts in both technology development and planetary defense," said DART mechanical engineer Betsy Congdon, who led the team during the installation. “With the successful installation and testing of two critical technologies, DRACO and ROSA, we're very confident that DART is ready to complete its final system testing and reviews before shipping to the launch site."
This November, the spacecraft will launch on a SpaceX Falcon 9 rocket from Vandenberg Space Force Base near Lompoc, California. In the fall of 2022, DART will have its sights set for Dimorphos, the smaller moonlet orbiting the larger Didymos asteroid. Its collision with Dimorphos will change the speed of the moonlet’s orbit around the main body by several minutes. And despite being approximately 6.8 million miles away from Earth at the time of impact, the asteroid system will be visible to ground-based telescopes, which scientists will use to determine the exact change in the orbital period.
Quelle: NASA
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Update: 6.10.2021
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NASA Invites Media to Launch of Double Asteroid Redirection Test
Media accreditation is open for the upcoming launch of NASA’s Double Asteroid Redirection Test (DART) mission, an evaluation of technologies for preventing a hazardous asteroid from striking Earth.
DART is targeted to launch at 10:20 p.m. PST, Nov. 23, 2021, (1:20 a.m. EST, Nov. 24), aboard a SpaceX Falcon 9 rocket from Vandenberg Space Force Base in California. Live coverage of the launch will air on NASA TV, the NASA app, and the agency’s website.
DART will be the first demonstration of the kinetic impactor technique, which involves sending one or more large, high-speed spacecraft into the path of an asteroid in space to change its motion. Its target is the binary near-Earth asteroid Didymos and its moonlet.
Credentialing deadlines are as follows:
- International media residing in the U.S. must apply by Friday, Oct. 8, 2021.
- U.S. media must apply by Sunday, Oct. 15, 2021.
NASA’s media accreditation policy is available online. Requests must be submitted online at:
NASA’s COVID-19 policies are updated as necessary and to remain consistent with guidelines issued by the Centers for Disease Control and Prevention and White House Safer Federal Workforce Taskforce. COVID-19 safety protocols for this event will be communicated closer to the date of the event. The agency also will communicate any updates that may impact mission planning or media access as necessary.
DART is directed by NASA's Planetary Defense Coordination Office to the Johns Hopkins University Applied Physics Laboratory in Laurel, Maryland with support from several NASA centers: the Jet Propulsion Laboratory in Southern California, Goddard Space Flight Center in Greenbelt, Maryland, Johnson Space Center in Houston, Glenn Research Center in Cleveland, and Langley Research Center in Hampton, Virginia. The launch is managed by NASA’s Launch Services Program, based at the agency’s Kennedy Space Center in Florida.
Quelle: NASA
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Update: 9.10.2021
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DART in transit to Vandenberg Space Force Base ahead of November 2021 launch
After completing months of tests and assembly, NASA’s Double Asteroid Redirection Test (DART) is in transit to Vandenberg Space Force Base (VSFB) in California ahead of its launch. DART is a first-of-its-kind NASA mission to demonstrate an asteroid deflection via a kinetic impact.
The probe will launch on a flight-proven Falcon 9 rocket from Space Launch Complex 4 East (SLC-4E) at VSFB no earlier than November 23 at 22:20 PST (06:20 UTC on November 24).
DART is NASA’s first planetary defense demonstration. It will attempt to impact Dimorphos, a moonlet of the asteroid Didymos.
The vehicle is a technology demonstrator built by the Johns Hopkins Applied Physics Laboratory (APL). APL completed the assembly of the primary spacecraft in November 2020. One of the final steps was the installation of NASA’s Evolutionary Xenon Thruster-Commercial (NEXT-C) ion engine. Thermal blankets and the high-gain antenna were later installed.
In February 2021, the nearly completed spacecraft began a months-long thermal and environmental test campaign. This confirmed that the spacecraft would survive the harsh environment of space. DART completed environmental testing in the spring of 2021, clearing the way for the APL team to integrate the spacecraft’s final components.
Following testing, DART was placed back inside the cleanroom at APL. The APL team then installed the spacecraft’s twin Roll-Out Solar Arrays (ROSA). The two ROSA panels will be used to power the spacecraft throughout its mission. The panels themselves are one of the technology demonstrations onboard DART.
The ROSA solar arrays are next-generation solar panels developed by Redwire. ROSA is designed to be more efficient and less bulky than other designs of solar panels and uses a flexible and rollable modular “wing” to extend the array. This wing will be lighter, more compact, and stiffer than traditional solar arrays.
The ROSA array was first tested onboard the International Space Station (ISS) after a successful launch on the SpaceX CRS-11 mission in 2017. This test array completed all but one mission objective – returning to its stowed configuration. It was jettisoned from the Station in its deployed position.
Today, a larger version of the ROSA, iROSA, is being used to help provide power to the ISS. Twin ROSA panels will also be used on the Power and Propulsion Element on NASA’s Lunar Gateway station.
A small portion of DART’s ROSA will use Transformational Solar Array technology, an experiment using higher-efficiency solar cells and reflective concentrators. Combined, these aim to provide three times more power than current solar array technology.
At the same time as the ROSA’s installation, the Didymos Reconnaissance and Asteroid Camera for Optical (DRACO) navigation camera was installed on the spacecraft. The DRACO camera is DART’s primary and only instrument.
DRACO is derived from the Long Range Reconnaissance Imager (LORRI) used on the New Horizons mission. The camera will be used for navigation and to conduct observations of Dimorphos. The camera will also be used to locate the impact site and the moonlet’s geologic properties.
Another version of LORRI will also be used on NASA’s Lucy Trojan explorer. This version will be called Lucy LORRI (L’LORRI). Lucy is currently preparing for launch as well, targeting liftoff on October 16, 2021.
Following the installation of both ROSA and DRACO, DART underwent another set of vibration tests to ensure the entire spacecraft was secure and ready for the stresses of launch. DART successfully passed these tests and was prepared for shipment to VSFB.
On September 8, the APL team installed the Light Italian CubeSat for Imaging Asteroids (LICIACube). LICIACube – a 6U CubeSat weighing 14 kg – was built by the Italian Space Agency (ASI). It is equipped with two optical cameras for imaging DART’s impact from a distance.
The two cameras, the LICIACube Unit Key Explorer (LUKE) and the LICIACube Explorer Imaging for Asteroid (LEIA), will capture scientific data and information on the microsatellite’s position as well as the effects of the impact, including the plume of ejecta and impact crater.
About 10 days before DART’s impact, LICIACube will be ejected from the host spacecraft, using a spring-loaded box, at a velocity of 1.1 m/s. LICIACube will then use its onboard propulsion to allow itself to fly past Dimorphos about three minutes after DART’s impact. Following the flyby, LICIACube will investigate the backsides of both Didymos and Dimophos.
After LICIACube was installed into the spring-loaded box, DART departed from Maryland to VSFB in late September 2021. Once it arrives, the spacecraft will undergo final testing ahead of its November 2021 launch.
DART will liftoff on a flight-proven Falcon 9 from SLC-4E. The Falcon 9 booster for this flight will be B1063-3. This booster previously supported two missions, Sentinel 6 Michael Frelich from VSFB in November 2020 and Starlink v1.0 L28 in May 2021.
Falcon 9 will carry DART, massing 610 kg, into an Earth-escape trajectory.
As the spacecraft coasts to Dimorphos, it will communicate to Earth via the Radial Line Slot Array (RLSA) antenna. RLSA is a low-cost, high-gain antenna that enables high-efficiency communications in a compact, planar form.
To reach its target, DART will use its NEXT-C ion engine along with its primary hydrazine thrusters. The NEXT-C engine is a brand-new ion engine developed by NASA’s Glenn Research Center, in partnership with Aerojet Rocketdyne.
NEXT-C is designed to have improved performance, thrust, and fuel efficiency compared to other ion engines. While NEXT-C is not the primary propulsion system, its inclusion on DART will help demonstrate the thruster’s potential for use on future deep-space missions. The engine is based on the NASA Technology Application Readiness (NSTAR) engine used on the Dawn and Deep Space 1 missions.
To control itself during its mission, DART will use the Small-body Maneuvering Autonomous Real-Time Navigation (SMART Nav) guidance, navigation, and control (GNC) system. The SMART Nav system is a GNC algorithm developed by the DART team to autonomously detect the Didymos system. The optical navigation system will work with other GNC elements to distinguish Dimorphos from Didymos roughly an hour before impact.
All of this will be controlled by DART’s CORE Small Avionics Suite (CORESAT). CORESAT is DART’s single-board computer and interface module. Both use field-programmable gate array-based electronics to allow flexible control over the data handling onboard the spacecraft.
After a several-month journey to the Didymos system, DART will target Dimorphos and impact at 6.7 km/s. The impact will take place in early October 2022 and is expected to alter Dimorphos’ 12-hour orbit around Didymos by several minutes by changing the moonlet’s orbital velocity by 0.5 millimeters per second.
Dimorphos is the moonlet of asteroid Didymos (Greek for twin). The Didymos system was discovered in April 1996 by the Kitt Peak National Observatory during a close pass of Earth. It was originally thought to be a single asteroid until 2003. In June 2020, Dimorphos was given its name. The system is currently in a 1 x 2.2 AU orbit around the Sun.
During the system’s next closest approach to Earth following impact, ground-based instruments will be used to study the altered bodies. However, DART is not the only mission set to reach the binary system.
DART is part of a joint NASA and European Space Agency (ESA) program called Asteroid Impact & Deflection Assessment (AIDA). AIDA’s main goal is to understand the effects of an asteroid impact by a spacecraft.
For its part, ESA will conduct a follow-on mission called Hera. It will launch onboard an Ariane 6 rocket with an Astris kick stage in 2024. Hera will arrive at the binary system in 2027 to get up-close observations of the changes made to Dimorphos after DART’s impact.
Hera itself is a simple spacecraft. It will mass just 870 kg and be equipped with multiple cameras and a LIDAR altimeter to determine how effective DART’s impact was.
The probe will also test new autonomous GNC systems while at Dimorphos for use in future interplanetary missions.
Hera will also carry two CubeSats of its own. The first is Milani, which will perform surface measurements of the two asteroids. This will be based on a 6U XL CubeSat and will have a mass of 12 kg.
The second CubeSat is called Juventas. It will line up with Hera to perform a satellite-to-satellite radio experiment and undertake a low-frequency radar survey of the asteroid’s interior. Toward the end of its month-long mission, the satellite will attempt to land on Dimorphos. Juventas will also be based on a 6U XL CubeSat and will have a mass of 12 kg.
DART is one of many future NASA missions to visit an asteroid. Before DART lifts off, the Lucy probe will launch to visit seven different asteroids – of which six are trojans of Jupiter.
Following DART’s launch, NASA’s Psyche mission will launch in August 2022 to the asteroid 16 Psyche, a metal-rich asteroid theorized to be the exposed metallic core of a protoplanet.
Data from these missions will help paint the picture of what the early solar system was like, as well as its evolution over time.
(Lead image: DART departing the Johns Hopkins Applied Physics Lab. (Credit: NASA/Johns Hopkins APL)
Quelle: NS
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Update: 22.10.2021
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Spacecraft for asteroid deflection experiment ready for fueling
A small spacecraft built for a NASA asteroid defense experiment arrived at Vandenberg Space Force Base in California earlier this month and is ready for fueling, one of the final milestones before liftoff in November on a SpaceX Falcon 9 rocket.
NASA’s Double Asteroid Redirection Test, or DART, spacecraft arrived at Vandenberg on Oct. 2 after a cross-country trip by truck from the Johns Hopkins University Applied Physics Laboratory in Laurel, Maryland.
Wishing a little more than a half-ton, DART is set for launch Nov. 23 at 10:20 p.m. PST (1:20 a.m. EST; 0620 GMT on Nov. 24) aboard a Falcon 9 rocket powered by a reused first stage booster. The mission has daily instantaneous launch opportunities through mid-February.
The Falcon 9 rocket will accelerate the spacecraft away from Earth on a trajectory toward asteroid Didymos, a rocky object about a half-mile (780 meters) in diameter.
Using a series of maneuvers with a xenon ion thruster, DART will take aim on Didymos’s smaller companion asteroid, called Dimorphos. The spacecraft will strike Dimorphos — about 525 feet (160 meters) wide — at nearly 15,000 mph (about 6.6 kilometers per second).
The primary science goal of the mission is to measure how the high-speed collision, which will destroy the DART spacecraft, disrupts the orbit of Dimorphos around nearby Didymos. The data could help plan a future mission to deflect an asteroid on a course to hit Earth.
Didymos and Dimorphos pose no near-term threat to Earth, but the asteroids will be close enough to our planet next year for astronomers to observe DART’s impact in late September using ground-based telescopes.
A small CubeSat provided by the Italian Space Agency will ride to space with DART, then deploy about 10 days before impact. The ridealong spacecraft, named LICIACube, will maneuver to a trajectory offset from DART, allowing it to safely fly by and watch the collision with a pair of optical cameras.
Since DART’s arrival at Vandenberg, engineers completed “basic electrical checkouts” to ensure the spacecraft remained healthy after the two-day road trip from its factory in Maryland, according to Betsy Congdon, the lead mechanical engineer for the DART mission at the Applied Physics Laboratory.
“Everything is working as planned, so now we’re getting into blanketing and final preparations for launch and fueling,” Congdon said Friday in an interview with Spaceflight Now.
This week, teams planned to move the DART spacecraft from an Astrotech processing facility to a nearby SpaceX clean room. Engineers completed the initial testing on DART at Astrotech, and will fuel the spacecraft with hydrazine at the SpaceX facility.
The hydrazine will feed 12 small rocket thrusters on the DART spacecraft. The rocket jets will be used for fine pointing of spacecraft during its 10-month flight to Didymos and Dimorphos.
The DART spacecraft shipped from the Applied Physics Laboratory with xenon gas already loaded for its ion propulsion system. The mission will be the first for a new high-efficiency electric thruster developed by NASA’s Glenn Research Center and Aerojet Rocketdyne.
The NASA Evolutionary Xenon Thruster-Commercial, or NEXT-C, thruster will adjust DART’s trajectory toward its asteroid target. The new thruster is an upgraded, more powerful version of ion propulsion system used on previous NASA deep space probes.
Ion propulsion systems operate at low thrust, but they can fire continuously for months or years while consuming relatively little fuel. They work by accelerating ionized gas using electricity. In DART’s case, the electricity will be generated by two roll-out solar panels.
The DART mission was supposed to launch in July, but NASA announced earlier this year that the launch would slip to November due delays in delivering the spacecraft’s primary instrument and solar arrays.
NASA said the delay was caused by “technical challenges” associated with the spacecraft’s Didymos Reconnaissance and Asteroid Camera for Optical navigation, or DRACO, imaging system, which needed to be reinforced to ensure it can survive the stresses of a rocket launch.
The DRACO camera will take pictures of the Didymos and Dimorphos asteroids just before impact.
The delivery of the spacecraft’s Roll-Out Solar Arrays, known as ROSA, was delayed due to supply chain issues, partly blamed on the COVID-19 pandemic.
But those problems appear to behind DART.
Congdon said Friday the final activities to ready the DART spacecraft for hydrazine fueling included the installation of protective thermal blankets and harnesses. The launch is on schedule for late November.
“We have many days of margin,” she said. “Everything’s looking really good.”
Quelle: SN
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Update: 29.10.2021
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