Astronatix's Intelsat 39 lists the two engines
Question: Why is this combination on Intelsat 39 called "hybrid" exactly? Do they operate together in some way? How are they operated (in combination or separately) to raise the spacecraft's orbit to GEO? Since all-electric is in vogue now, why have the R-4D at all?
- IS-39 has a hybrid orbit raising system similar to IS-38
- "...and will use hybrid electric and chemical propulsion to reach its desired orbit..." 1, 2, 3