Comet Interceptor

File:Comet Interceptor.png

File:Comet Interceptor ESA mission - Sketch of the Comet Interceptor flyby.png

File:At Noordwijk 2024 092.jpg

Long-period comets have highly eccentric orbits and periods ranging from 200 years to millions of years,{{cite web |url=http://pds.jpl.nasa.gov/planets/special/smbod.htm |title=Small Bodies: Profile |work=JPL |publisher=NASA |archive-url=https://web.archive.org/web/20130430133726/https://pds.jpl.nasa.gov/planets/special/smbod.htm |archive-date=30 April 2013 |url-status=dead |date=29 October 2008 |access-date=11 August 2013}} so they are usually discovered only months before they pass through the inner Solar System and return to the distant reaches of the outer Solar System, which is too little time to plan and launch a mission. Therefore, ESA will "park" the Comet Interceptor spacecraft on a stable halo orbit around the Sun-Earth L₂ point and wait for the discovery of a suitable comet that it can reach for a close flyby.{{cite web |last=Jones |first=Geraint |url=http://www.cometinterceptor.space/uploads/1/2/3/7/123778284/comet_interceptor_executive_summary.pdf |title=Comet Interceptor - Executive Summary |work=Comet Interceptor Consortium |publisher=ESA |date=2 June 2019 |access-date=15 December 2022}}

The Comet Interceptor mission is unique in that it is designed to encounter an as-yet unknown target, having to wait between 2 and 3 years for a target it can reach with a reasonable change in velocity (delta-v) within a total mission length of approximately 5 years.{{cite web |url=https://www.cometinterceptor.space/mission.html |title=Comet Interceptor - Mission |work=Comet Interceptor Consortium |publisher=ESA |access-date=1 July 2019}} The baseline design is solar electric propulsion.

Finding a suitable comet to fly by will rely on ground-based observational surveys such as Pan-STARRS, ATLAS, or the future Vera C. Rubin Observatory's Legacy Survey of Space and Time (LSST). In the case that no long-period comet can be intercepted in time, a backup short period comet (baseline: 73P/Schwassmann–Wachmann) can be studied. There is also the potential of intercepting an interstellar object passing through the Solar System, if the speed and direction permit.{{cite web |last=O'Callaghan |first=Jonathan |url=https://www.scientificamerican.com/article/european-comet-interceptor-could-visit-an-interstellar-object/ |title=European Comet Interceptor Could Visit an Interstellar Object |work=Scientific American |date=24 June 2019 |access-date=15 December 2022}}{{cite web |last=Gough |first=Evan |url=https://www.universetoday.com/142676/meet-the-comet-interceptor-itll-wait-patiently-in-space-for-a-comet-then-pounce-on-it/ |title=Meet the Comet Interceptor. It'll Wait Patiently In Space for a Comet, Then Pounce On It |work=Universe Today |date=29 June 2019 |access-date=15 December 2022}}

The mission's primary science goal is stated as "to characterise, a dynamically-new comet, including its surface composition, shape, structure, and the composition of its gas coma."{{cite web |url=https://www.cometinterceptor.space/science.html |title=Comet Interceptor - Science |work=Comet Interceptor Consortium |publisher=ESA |access-date=1 July 2019}}

Comet Interceptor is being developed as ESA's first Fast class (F-class) of the Cosmic Vision programme. The mission is being planned and developed by a consortium that includes the ESA and Japan's space agency JAXA. Comet Interceptor will share the launch vehicle with ESA's ARIEL space telescope, which is also bound for Lagrange point 2.

File:Comet Interceptor instruments.png

One-two days before the comet flyby, the main spacecraft (spacecraft A) will deploy two small probes (B1 and B2) to venture even closer to the target, carrying complementary instrument payloads and to sample the coma.{{Cite web|url=https://www.esa.int/Science_Exploration/Space_Science/Comet_Interceptor/Comet_Interceptor_factsheet|title=Comet Interceptor factsheet|website=www.esa.int}}{{cite web |last=Lakdawalla |first=Emily |url=https://www.planetary.org/articles/esa-to-launch-comet-interceptor |title=ESA to Launch Comet Interceptor Mission in 2028 |work=The Planetary Society |date=21 June 2019 |access-date=15 December 2022}} Each of the three spacecraft will sample gas composition, dust flux, density, magnetic fields, and plasma and solar wind interactions, to build up a 3D profile of the region around the comet.{{cite web |last=Rabie |first=Passant |url=https://www.space.com/comet-interceptor-mission-to-undiscovered-object.html |title=A Triple-Threat 'Comet Interceptor' Could Explore an Undiscovered Space Object |work=Space.com |date=21 June 2019 |access-date=15 December 2022}}

• In 2019, Comet Interceptor has been selected as ESA’s new Fast-class mission.{{Cite web |title=Comet Interceptor concept |url=https://www.esa.int/ESA_Multimedia/Images/2019/06/Comet_Interceptor_concept |access-date=2025-03-16 |website=www.esa.int |language=en}}{{Cite journal |last=Snodgrass |first=Colin |last2=Jones |first2=Geraint H |date=2019 |title=The European Space Agency’s Comet Interceptor lies in wait |url=https://www.nature.com/articles/s41467-019-13470-1 |journal=Nature Communications |language=en |volume=10 |issue=1 |doi=10.1038/s41467-019-13470-1 |issn=2041-1723 |pmc=6882810 |pmid=31780664}}

• In June 2022, the mission was adopted by ESA during the Agency’s Science Programme Committee.{{Cite web |title=Comet Interceptor approved for construction |url=https://www.esa.int/Science_Exploration/Space_Science/Comet_Interceptor/Comet_Interceptor_approved_for_construction |access-date=2025-03-16 |website=www.esa.int |language=en}}{{Cite web |title=ESA Gives Green Light on its Comet Interceptor Mission |url=https://www.universetoday.com/articles/esa-gives-green-light-on-its-comet-interceptor-mission |access-date=2025-03-16 |website=Universe Today |language=en}}

• In December 2022, ESA and OHB have signed a contract to move forward with the design and construction of the spacecraft.{{Cite web |title=Comet Interceptor construction moves forward |url=https://www.esa.int/Science_Exploration/Space_Science/Comet_Interceptor/Comet_Interceptor_construction_moves_forward |access-date=2025-03-16 |website=www.esa.int |language=en}}

• In 2023, the Estonian Space Office decided to support the development of OPIC, a camera system designed by the University of Tartu.{{Cite web |title=Estonia pioneers instrument for Comet Interceptor mission through Prodex |url=https://www.esa.int/About_Us/Business_with_ESA/Estonia_pioneers_instrument_for_Comet_Interceptor_mission_through_Prodex |access-date=2025-03-16 |website=www.esa.int |language=en}}{{Cite web |last=Dorminey |first=Bruce |title=Estonia Building Imager For ESA Mission To Intercept Long-Period Comet |url=https://www.forbes.com/sites/brucedorminey/2023/08/23/estonia-building-imager-for-esa-mission-to-intercept-pristine-comet/ |access-date=2025-03-16 |website=Forbes |language=en}}

• In July 2024, the spacecraft's magnetometer boom was undergoing vibration testing{{Cite web |title=Comet Interceptor’s boom gets shaken, not stirred |url=https://www.esa.int/ESA_Multimedia/Videos/2024/06/Comet_Interceptor_s_boom_gets_shaken_not_stirred |access-date=2025-03-16 |website=www.esa.int |language=en}}
• In September 2024, MMA Space was selected to provide solar panels for the Probe B1.{{Cite web |last=sorzano |first=sandy |date=2025-02-10 |title=MMA Space announces a contract award for solar arrays to power a small probe on the Comet Interceptor Mission |url=https://mmadesignllc.com/2025/02/mma-announces-contract-comet-interceptor-mission/ |access-date=2025-05-25 |website=MMA Space |language=en-US}}[https://mmadesignllc.com/download/39670/?tmstv=1748170847 MMA announces contract award for solar arrays to power small probe on Comet Interceptor Mission]

• In November 2024, the Probe B2’s structural qualification model passed all mechanical tests and was pronounced structurally sound.{{Cite web |title=Comet Interceptor’s probe proves structurally sound |url=https://www.esa.int/ESA_Multimedia/Images/2024/11/Comet_Interceptor_s_probe_proves_structurally_sound |access-date=2025-03-16 |website=www.esa.int |language=en}}

• In December 2024, OHB Czechspace in Brno, Czechia assembled a testing article of the dust shield before transporting it to IABG test facilities in Germany.{{Cite web |title=OHB Czechspace is assembling the Comet Interceptor dust shield |url=https://www.ohb-czech.cz/news/ohb-czechspace-is-assembling-the-comet-interceptor-dust-shield |access-date=2025-03-16 |website=OHB Czechspace |language=en-GB}}{{Cite web |title=V Brně se chystá konstrukce pro misi Comet Interceptor – Kosmonautix.cz |url=https://kosmonautix.cz/2024/11/28/v-brne-se-chysta-konstrukce-pro-misi-comet-interceptor/ |access-date=2025-03-16 |language=cs}}
• In May 2025, ESA received results of the Latvian project CI3D — photorealistic computer-generated images that will be used for testing the spacecraft's cameras under various conditions around the unknown target body{{Cite web |title=European Space Agency's "Comet Interceptor" Mission Utilises Comet Models Developed in Latvia {{!}} researchlatvia |url=https://www.researchlatvia.gov.lv/index.php/en/european-space-agencys-comet-interceptor-mission-utilises-comet-models-developed-latvia |access-date=2025-05-17 |website=www.researchlatvia.gov.lv |language=en}} Redwire Corporation has also delivered the spacecraft's flight computer.{{Cite web |title=Redwire delivers flight computer for ESAs Comet Interceptor mission targeting primordial comet |url=https://www.spacedaily.com/reports/Redwire_delivers_flight_computer_for_ESAs_Comet_Interceptor_mission_targeting_primordial_comet_999.html |access-date=2025-05-29 |website=Space Daily}}

• ARIEL – Launching on the same rocket
• List of European Space Agency programmes and missions

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