Detecting space hazards:ESA's graphic for the Space Situational Awareness programme
TheSpace Safety Programme (S2P), formerly theSpace Situational Awareness (SSA) programme,[1][2] is an initiative by theEuropean Space Agency (ESA) to monitor hazards from space, determine their risk, make this data available to the appropriate authorities, and where possible, mitigate the threat.[3] The programme focuses on 3 areas:space weather forecasting andnowcasting,asteroid impact prediction andprevention, andspace debris mitigation.[4] S2P is being implemented as an optional ESA programme[5][6] with financial participation by 14 Member States.[citation needed]
The programme started in 2009 and its mandate was extended until 2019. The second phase of the programme received €46.5 million for the 2013–2016 period.[9] The original SSA Programme was designed to support Europe's independent space access and utilization through the timely and accurate information delivery regarding the space environment, particularly hazards to both in-orbit and ground infrastructure.[10] In 2019 it evolved into the present Space Safety Programme (S2P) with an expanded focus, also including missions and activities to mitigate and prevent dangers from space.[11]
At the ESA ministerial council in 2025, member states committed to a budget of €955 million for S2P over the following three years, increasing the budget by 30%. These funds were even higher than what the programme requested and covered all plans outlined in the proposal published before the council.[8][12]
The programme is split into three "Cornerstones" managing major missions and six "COSMIC" areas managing small missions and other aspects of the programme:[13][8]
S2P'sspace weather projects are monitoring the activity of theSun, thesolar wind, and Earth'smagnetosphere,ionosphere, andthermosphere, that can affect spaceborne and ground-based infrastructure or endanger human life or health. This data is processed and made available freely via the Space Weather Service Network.[14] The upcoming deep-space missionVigil, designed to observe the Sun from the Sun-EarthLagrange point L5, will contribute to this monitoring system, allowing for timely warnings.[15]
Planetary Defence at ESA focuses on detecting natural objects, such asasteroids andcomets, which can potentiallyimpact Earth, gathering observations from telescopes around the world and plotting their path through the sky to calculate the impact risk.[16] Another area of the Cornerstone's activity is coordinating the response to a possible impactor with the international community through groups such as the International Asteroid Warning Network (IAWN)[17] and the Space Mission Planning Advisory Group (SMPAG).[18] The European asteroid observation network is coordinated by the S2P'sNear-Earth Object Coordination Centre (NEOCC).[4]
In October 2024, ESA launched theHera mission, a follow-up toNASA'sDART mission which performed the first kinetic impact test of Planetary Defence on 26 September 2022. Hera will rendezvous with the impactedDidymos binary asteroid system in 2026 to study the crater formed, the dust plume released, and more.[19] S2P is working on two other asteroid exploration missions, theHera-derivedRamses and the smallerCubeSat-typeSatis.[4] S2P is also developing the asteroid-detectingspace telescope namedNEOMIR that will be placed in the Sun–EarthLagrange point L1.[4]
Space debris projects at ESA are tracking active and inactivesatellites andspace debris to better understand the debris environment, providing data, analysis, and advice to spacecraft engineers to perform collision avoidance manoeuvres, as well as developing a system of automated collision avoidance. The space debris office also works with the international community on norms and standards for the sustainable future of space.[20][21][22][23]
Clean Space projects aim for systematically considering the entire life-cycle of space activities, from the early stages of conceptual design to the mission's end of life and beyond, to removal of space debris.[24][25][26] ESA Clean Space includes EcoDesign (embedding environmental sustainability within space mission design), management of end-of-life, developing technologies to prevent the creation of future debris, in-orbit servicing/active debris removal, removing spacecraft from orbit, and demonstrating in-orbit servicing of spacecraft.[27][28][29]
Earth-orbitingspace weather missions likeSWING,Aurora-C, andSWORD will form the Distributed Space Weather Sensor System (D3S)[4] complementing the deep-space observations byVigil.[8]
Hera, launched October 2024 – European asteroid probe aimed at studying the effects of aNEO'simpact created by NASA'sDART mission using65803 Didymos's moon (Dimorphos) as a target
Draco, launching in 2027 – small space capsule monitoring the breakup and demise processes of a re-entering satellite[39][40][35]
The main objective of thespace weather segment (SWE) was to detect and forecast ofspace weather events, avoid adverse effect on European space assets and ground-based infrastructure. To achieve that, the segment focused on delivery of real-time space weather information, forecasts and warnings, supported by a data archive, applications and services. Assets available for the segment consisted of multiple ground-based and spaceborne sensors monitoring the Sun,solar wind and Earth'smagnetosphere,ionosphere andthermosphere. These included thePROBA2 satellite and theKanzelhoehe Solar Observatory. The segment was jointly coordinated by the SWE Data Centre located at theESTRACKRedu Station and the SSA Space Weather Coordination Centre (SSCC), both inBelgium.[54]
Thenear-Earth object segment aimed to deliver monitoring and warning of potentialEarth impactors and tracking of newly discovered objects. The segment's assets consisted of a mixture of professional and amateur telescopes, including theOGS Telescope, that were supported by tracking databases. The plans were to create a fully integrated system supporting alerts for civil authorities, including theFlyeye (NEOSTEL) telescope planned for completion in 2020. The segment was operated by the SSANEO Coordination Centre located at theESA Centre for Earth Observation, Italy.[55]
The SST segment's primary goal was the detection, cataloguing and orbit prediction of objects orbiting the Earth. It was part of an effort to avoid collisions between orbiting satellites and debris, provide safe reentries, detect on-orbit explosions, assist missions at launch, deployment and end-of-life and overall reduce cost of space access. The segment relied on existing European radar and optical systems. Some of its assets were existingradio andoptical telescopes, serving a secondary role for tracking space debris.[56]
The radar-based SST assets were split into two categories: surveillance and tracking systems. SSA SST radar systems included:[57]
As part of the SSA Programme new, dedicated surveillance radar supported by optical sensors systems were planned to be developed. The segment was coordinated by the Space Surveillance Test & Validation (SSTC) Centre located at theESAC inSpain.[56] Close approaches ofNear-Earth objects and near earth asteroids were reported by ESA through the space situational awareness center.[60]
^Jilete, Beatriz; Lemmens, Stijn; Eynde, Jeroen Van Den; Rosenbaum, Alex; Climent, Sara Sanchis; Beck, James; Loehle, Stefan; Turchi, Alessandro; Sakraker, Isil; Ferreira, José P.; Helber, Bernd; Tarabini-castellani, Lorenzo; Minacapilli, Paolo (2025)."DRACO scientific return concept: determining the truth of satellite demise".9th European Conference on Space Debris.
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