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\t\t\t\t\t\t22\/08\/2024<\/span> On 8 September 2024, the first of four satellites that make up ESA\u2019s\u00a0Cluster\u00a0mission will reenter Earth\u2019s atmosphere over the South Pacific Ocean Uninhabited Area.<\/p>\n This marks the end of the historic mission, over 24 years after it was sent into space to measure Earth\u2019s magnetic environment. Though the remaining three satellites will also stop making scientific observations, discoveries using existing mission data are expected for years to come.<\/p>\n This \u2018targeted reentry\u2019 is the first of its kind. ESA\u2019s efforts to ensure a clean end to the Cluster mission go beyond international standards, making the agency a world-leader in sustainable space exploration.<\/p>\n<\/div>\n Launched in 2000, Cluster has spent 24 years studying perhaps the one thing that makes Earth a unique habitable world where life can thrive: its powerful magnetic shield, the magnetosphere.<\/p>\n Like an enormous umbrella, the magnetosphere protects us from most of the driving rain of particles that the Sun relentlessly sends in our direction.<\/p>\n But gusts of this solar wind can still push through, sending bursts of energetic particles cascading towards Earth\u2019s surface. The most common result is the northern and southern lights (auroras), but more rarely, these particles can cut our power supplies, disrupt radio communications, or damage satellites.<\/p>\n<\/p><\/div>\n We call the influence of the solar wind on Earth\u2019s magnetic environment \u2018space weather\u2019.\u00a0 And until Cluster came along, space weather remained something of a mystery.<\/p>\n \u201cFor over two decades, Cluster has shown us time and time again how important the magnetosphere is in shielding us from the solar wind,\u201d says Cluster Mission Manager Philippe Escoubet. \u201cIt has watched the effects of solar storms to help us better understand and forecast space weather.\u201d<\/p>\n<\/p><\/div>\n Cluster was never designed to last this long, nor was it designed for such a safe finale. It was initially launched on a two-year mission to study the Sun\u2013Earth interaction. Because it was carrying out such impressive and world-changing science, ESA\u2019s spacecraft operators kept it going.<\/p>\n But all good things must come to an end, and Cluster\u2019s time has finally come. With this targeted reentry, ESA is turning Cluster from a pioneer in space weather monitoring to a pioneer in mitigating space debris \u2013 two key elements in the agency\u2019s space safety goals.<\/p>\n Without intervention, the four Cluster satellites would have reentered naturally in a less predictable manner, potentially over a more densely populated region. By targeting the satellites reentries, ESA is taking the opportunity to ensure that Cluster\u2019s demise doesn\u2019t contribute to the rocketing amount of space junk in orbit around Earth.<\/p>\n<\/p><\/div>\n Of the four Cluster satellites \u2013 nicknamed Rumba (Cluster 1), Salsa (Cluster 2), Samba (Cluster 3) and Tango (Cluster 4) \u2013 Salsa will be the first to take the plunge back into Earth\u2019s atmosphere. It is targeting a specific region of the South Pacific Ocean that is as far as possible from populated regions.<\/p>\n \u201cBack in January we tweaked Salsa\u2019s orbit to make sure that on 8 September it experiences its final steep drop from an altitude of roughly 110 km to 80 km,\u201d explains Cluster Operations Manager Bruno Sousa. \u201cThis gives us the greatest possible control over where the spacecraft will be captured by the atmosphere and begin to burn up.\u201d<\/p>\n<\/p><\/div>\n Bruno\u2019s team is now watching the satellite from a distance. A targeted reentry allows for so much predictability in the reentry time and location that there is no need for further manoeuvres.<\/p>\n Despite being confident that no surviving fragments will fall anywhere near land, we still have very little data about how spacecraft behave as they pass through the lower layers of the atmosphere. We would like to know more to predict even better the time and location of satellite reentries and ensure the safety of humans on Earth.<\/p>\n ESA is considering observing Salsa\u2019s reentry from an aircraft; this will be confirmed later in August. The four Cluster satellites are identical and so by watching them reenter the atmosphere with slightly different trajectories and in different weather conditions, we would have the unique opportunity to conduct a valuable reentry experiment to study the break-up of satellites.<\/p>\n<\/p><\/div>\n Cluster\u2019s reentry follows those of ESA\u2019s Aeolus and ERS-2 Earth observation missions. ESA is setting a precedent for a responsible approach to reducing the every-increasing problem of space debris and uncontrolled reentries.<\/p>\n With this targeted reentry, ESA is again pioneering a new strategy to reduce its environmental impact by disposing of its missions more safely and sustainably than envisaged at the time of their design.<\/p>\n \u201cBy studying how Salsa burns up, which parts might survive, for how long and in what state, we will learn much about how to build \u2018zero-debris\u2019 satellites,\u201d explains Tim Flohrer, Head of ESA\u2019s Space Debris Office.<\/p>\n \u201cThe lessons learned from this activity will help turn targeted reentries into a safe and well-understood option for the disposal of other space missions in similar orbits, such as\u00a0Smile\u00a0and\u00a0Proba-3.\u201d<\/p>\n Following Salsa\u2019s reentry, the three remaining Cluster satellites will enter \u2018caretaker\u2019 mode; whilst they will not be making scientific measurements, operators will be monitoring them to minimise the risk of collision with other satellites or Earth itself.<\/p>\n Bruno\u2019s team will adjust the orbit of Rumba (Cluster 1) in August 2024 in preparation for a similar targeted reentry in November 2025. They will then manoeuvre Samba (Cluster 3) and Tango (Cluster 4) in November 2024 ready for Cluster\u2019s final goodbye in August 2026.<\/p>\n<\/p><\/div>\n At the end of 2025, ESA plans to launch its next mission to tackle Earth\u2019s magnetic environment: the Solar wind Magnetosphere Ionosphere Link Explorer, or Smile for short. A joint venture with the Chinese Academy of Sciences, Smile will build upon Cluster to reveal even more about the complex and intriguing magnetic environment surrounding planet Earth.<\/p>\n Leading up to and during Salsa\u2019s reentry we will be providing updates via the Rocket Science blog, and the @ESA_Cluster<\/a>, @esaoperations<\/a> and @esascience<\/a> Twitter accounts.<\/p>\n \u00a0<\/p>\n For more information, please contact ESA Media Relations:<\/b><\/p>\n media@esa.int<\/p>\n<\/p><\/div>\n
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\n\t\t\t\t\t\t\t\t\t\t0<\/span> likes<\/small><\/span><\/p>\n<\/header>\nSpace safety take I: a lifetime monitoring space weather<\/h3>\n
\n\t\t\t\t\t\t\t\t<\/figcaption><\/figure>\nSpace safety take II: a zero-debris finale<\/h2>\n
Salsa\u2019s last dance<\/h2>\n
\n\t\t\t\t\t\t\t\t<\/figcaption><\/figure>\n<\/p><\/div>\nA brighter future<\/h2>\n
\n\t\t\t\t\t\t\t\t<\/figcaption><\/figure>\nWhat\u2019s next?<\/h3>\n
\n\t\t\t\t\t\t\t\t<\/figcaption><\/figure>\n<\/p><\/div>\n