1. Swarm constellation options
Separation of Swarm-B and Swarm-A/C orbital planes
B  A/C Keep separation in the range DLTAN 4h-8h ( deg) as long as possible
B  A/C Continue with the natural drift
Separation of Swarm-A and Swarm-C orbital planes
A  C Increase DRAAN 1.4 deg  2.8 deg or 10.0 deg
“Inertial” pearl of strings (= same orbit) as close of possible
“Earth fixed” pearl of strings (= same ground track). 20 seconds apart
As close as possible
Orbit altitude of B
Keep Swarm-B at ~500 km for as long as possible
Reach the 2030 solar minimum with Swarm-B
Orbit altitude of A/C
Reach the 2020 solar minimum with Swarm-A/C with an altitude around 350 km and then extend the mission as much as possible
Reach the 2030 solar minimum with Swarm-A/C
Maximal air drag density / acceleration

2. Option 4a Reach the 2020 solar minimum with Swarm-A/C with an altitude around 350 km and then stay as long as possible
Solar Min
Solar Max
450km
40kg
10kg
20km
10kg
10kg
8kg
40km
20kg
10kg
20kg
400km
60km
30kg
7kg
380km
5kg
42kg
50kg
25kg
33kg
350km
20kg
All curves are for Swarm-A/C and 50th percentile case of solar activity