Safe trip AWS!

The Arctic Weather Satellite (AWS) was launched on 16 August on board a Falcon 9 rocket, following a very fast development phase by ESA and industrial partners – just 36 months. The satellite is now on its way to its final orbit, from where it will start distributing data on the humidity and temperature of the atmosphere in approximately one month.

And then?  The quality of the AWS data will be carefully scrutinised by EUMETSAT’s member states as one of the important elements in decision-making for the vote on the proposed follow-on constellation, expected by mid-2025. The constellation, called “EUMETSAT Polar System (EPS)-Sterna” would ensure that six small satellites similar to AWS constantly orbit around the Earth on three different planes, for 13 years starting in 2029. A study published in 2023 estimates the socio-economic benefits to cost ratio of EPS-Sterna at 51:1, which demonstrates the very high strategic value of this investment. The real data from AWS is expected to confirm the performance levels assumed in this study, and will influence the decision to build EPS-Sterna.

“AWS was designed based on requirements collected by EUMETSAT from its data users, with the long-term vision of developing the EPS-Sterna constellation, explains Christophe Accadia, Passive Microwave and Radio Occultation Competence Area Manager at EUMETSAT. “Now we are very keen to assess whether this prototype answers the needs  expressed by our users as it will obviously have consequences for the development of the EPS-Sterna constellation.”

In this context, the calibration and validation of the microwave sounding instrument on board AWS will be crucial. EUMETSAT will collaborate with the Swedish Meteorological and Hydrological Institute (SMHI) on this critical step to evaluate the quality of the satellite’s data and, further down the line, assess its real impact.

In addition, gaining some experience now on the calibration and validation of such a sounder will provide some valuable lessons for later, when EUMETSAT will need to run the same step on its own satellites. In addition to the potential EPS-Sterna constellation, the first satellite of the EPS-Second Generation series that will be launched successively from 2025 will also have a microwave sounder on board.