ARIEL is the fourth medium-class (M4) mission in ESA's Cosmic Vision Plan. It is scheduled for launch in 2028.
Launch and orbit
ARIEL will be launched into an (Earth-Moon) eclipse-free orbit around the Sun-Earth L2 point. It will be a large amplitude quasi-halo orbit, as was the case for ESA's Herschel Space Observatory, where the angle between the Sun, Spacecraft, and Earth can be ≥ 30 degrees. From ARIEL's planned orbit, the complete sky is accessible within 3 months, with a source at the ecliptic observable for at least 30% of the mission lifetime.
The proposed launch vehicle is an Ariane 62, a modular launcher with two P120 solid-propellant boosters.
The Launch and Early Operations phase will cover the time until the first Transfer Correction Manoeuvre is executed (within 2 days after launch). It will then take ARIEL up to six months to reach operational orbit, go through spacecraft commissioning and science demonstration phases. Once in its final configuration, ARIEL will perform one manoeuvre per month to maintain its orbit.
ARIEL has a nominal 4-year operational timeline, consisting of 6 months of launch and early operations, commissioning, performance verification, and science demonstration phases, followed by a 3.5 year duration routine science operations phase, with a potential extended science operations phase lasting for two further years.
A payload consortium funded by national agencies will provide the full ARIEL payload (the complete payload module, including telescope and instruments, and the warm payload units) and will have significant involvement in the science ground segment, while ESA will provide the service module, the integration and testing of the spacecraft flight model, as well as being responsible for the launch and operations.
The ground segment responsibility and implementation will be split between ESA and a nationally-funded Instrument Operations and Science Data Centre (IOSDC) payload consortium. ARIEL data products will be distributed to the scientific community through an ESA-provided science archive.
ESA will provide:
- A Mission Operations Centre (MOC) located at the European Space Operations Centre (ESOC) in Darmstadt, Germany
- A Science Operations Centre (SOC) located at the European Space Astronomy Centre (ESAC), in Madrid, Spain
- ESA tracking station network (ground stations)