Why on Earth (or Phobos, in this case) would a (1) civilian probe need to encrypt its telemetry data? And why would the (2) probe's manufacturers not have the key to the encryption?
(1) I'll tell ya why. Because it is the data itself that is proprietary, and it needs to be "filtered" before the public is "granted" limited access. But it also may be that the translation is inadequate, since "coding", generally, would be expected. As to whether or not it is fine to keep the public in the dark as to the data, I recognize that after spending all the money they have on the probe, that they would be jealous of that data, and the next legitimate question, by UGordon is legitimately asked: "Why should anyone else be able to eavesdrop and steal telemetry?" The answer to that would be in asking the question, What then is the
real meaning of "we come on behalf of all mankind", and other similar agency blandishments. For me, that is a very interesting side discussion, but I don't have a pat answer.
(2) That, I couldn't guess. But I think both questions are legitimately asked.
Obviously uplink needs to be seriously encrypted. That downlink encrypting is thought to be "simply an impediment to troubleshooting", shows that the impediment then can "simply" be the proximate cause of some types of failure.
What is your expertise in the field to claim you know what should be done and how the whole telemetry bitstream is or should be handled in the first place?
The same thing was asked of me when I questioned, with the "expertise" of 20-20 hindsight, the wisdom of confusing imperial and metric units in our failed martian probe. An explanation of the benefits and detriments of downlink encoding would be far more helpful to everyone. Again, regarding expertise, the "amateur" rightly would think that the "experts" would have considered
beforehand the contingency plans.
That is the fundamental difference between amateurs and experts.
Note that the extra fuel tank is thought to have been an impediment to communication as well, and the possibility of its failure to have separated may not have been considered during the design of the mission. Eventually, there will be a de-briefing of some sort regarding the failure. My prediction is that the managerial DNA of the Russians is virtually identical to American managers, when the time comes to accept responsibility for errors. "Not me", and "we never thought of that", are two phrases which can be directly translated from English to Russian. Savvy?
More to the point: Can F-G be saved? Can it be parked into a higher stable orbit where atmospheric drag is minimized, so as to stay up there for a period until the next window opens? Could there be a Russian rescue mission? It would be a shame to lose that machine.