Data collection from the spacecraft: Colors stand for the data collected by each spacecraft communicating with the ground segment. Data from four spacecraft is downloaded every 15 min with two antennas on Earth. For each such interval the downlink time from spacecraft sending imaging and in-situ (C + IS) data takes 9 min. The antennas then switch to the next spacecraft through a 1 min pointing procedure and download only the in-situ (IS) measurements from the other spacecraft.