Re: "The satellite would thus know to keep one of its receiving assemblies aligned..."
Having spent far too much time following the ever-expanding thread on PPRuNe, I found this a good summary. Some issues with it (like the purported alignment of receiving assemblies) but better than most media.
From my perspective, the big unanswered question about INMARSAT is what about the other pings? The distance from the satellite calculated from the final ping is being discussed, but what about the preceding ones. These would give us an indication if whether the plane was moving, and what approximate direction. You could use this information to infer whether the plane was likely to be in the southern or northern corridors for example, and it would certainly be useful to know if it had stopped moving with respect to the satellite. However, this information has not been given - and frustratingly journalists have not asked for it in the press conferences. It's entirely possible that only the last ping was retained by the system, but it would be good to know that.
I would also be interested in what level if detail the system recorded ping send/receive times. +/- 1 ms implies a particular level of accuracy, if this is greater or less then accuracy is changed, possibly significantly. I've not seen this reported anywhere.
With the conspiracy hat on, I find it amazing that no journalist in the press conferences has pressed for a cargo manifest. The only concrete statement made by the authorities is that "nothing hazardous" was on board. A very valuable cargo has not been ruled out. If there was nothing valuable on board, why not explicitly and unambiguously rule this out?
The standard of both questions and answers at the press conferences is terrible. Take the ACARS being allegedly switched off before the last voice transmission. Crucial point but turns out it was misleading; accurate version is that last ACARS transmission was *sent* before last voice contact. Actual ACARS disabling time may have been later. Bad communication of facts, and an equally bad failure to seek clarification from the journos present.
The whole thing is a masterclass in how not to run an investigation and handle the associate public relations. Unless of course [tin foil hat!] it is all an act of pretend incompetence :)