A brief follow-up to What will MOM do when Earth isn't looking?
As already premised in the referenced question; terrestrial artifacts on/around Mars encounter a communications blackout every 26 months, or so. This article conveys the blackout may be more of a precautionary note to avoid a corrupt command from throwing a spoke in the wheel.
Is there, today, a relatively error-free means to communicate with orbiters/rovers on the Martian surface whilst Sol occults Earth/Mars?
p.s. The impression from the answer chain indicates it is possible to bounce signals off other craft, and may have been done during the Apollo program. Perhaps other long-term missions too. As a follow-up question - Have there been any instances of a terrestrial robot on/around Mars actually communicating thus? What was/were the relay/s involved, and the circumstances under which it was done?