Q: What is Swarm?
A: Swarm is the fifth mission in ESA's fleet of Earth explorers. Its main scientific goals are to provide the best-ever survey of the geomagnetic field (including its temporal evolution) and the electric field in the atmosphere.

Q: Why do you carry two magnetometers per satellite?
A: Besides other scientific payloads, each Swarm satellites carries an absolute scalar magnetometer (ASM) and a vector field magnetometer (VFM). The scalar measurements of the ASM are used to calibrate the VFM.

Q: What are the official names of the satellites?
A: For the time being the names of the satellites are Swarm Alpha, Bravo and Charlie (sometimes abbreviated to Swarm A, B and C). Alpha and Charlie form the lower pair flying side by side, whereas Bravo is the lonely satellite on the higher orbit.

Q: How are the measurements validated?
A: Besides the engineering validation performed by industry and ESA, the scientific community is highly involved in the scientific validation of all data products. A dedicated calibration /validation team consisting of 23 world wide leading scientific institutions validate the scientific content of all data products generated by the Ground Segment. At dedicated workshops all the findings are presented to ESA, driving a possible evolution with respect to data quality.

Q: What orbits are the satellites using?
A: Swarm Alpha and Charlie are on a nearly circular orbit with an inclination of 87.35º at an altitude of 462 km. Swarm Bravo is on an orbit with an inclination of 87.75º at an altitude of 510 km. The reason for these different orbits is to maximise the scientific return of the mission during its lifetime.

Q: Why is there a need for a constellation of three satellites?
A: Sometimes 1+1+1 is more than 3. This is also the case for the Swarm mission. To maximise the scientific return with respect to geomagnetic and electric field research, a constellation of three identical satellites on different orbits is ideal.

Q: Are the satellites identical?
A: Yes.

Q: If this FAQ does not answer my question, what should I do?
A: All queries regarding Swarm should be directed to the Swarm Team (swarm_feedback@esa.int).