Sol 150+, Time marches on... Options

[Stu]

Sol 150 raws are up so this seems like a good time to start a new thread...

Hang on in there Phoenix...

[Deimos]

I'm not aware of any recoverable science data still on board, other than maybe in the MET/Lidar flash. The Biblical Lazarus may have come back with memory intact, but Phoenix comes back thinking it is the day before launch (or some such) and wondering why the touchdown sensors indicate she has landed. And so, Phoenix realizes something has gone very wrong, and begins the Lazarus mode comm strategy.

It looks like the weather situation may have improved, but there is no science and little engineering data to directly confirm that. As Emily said, once there is a good comm session, JPL can regain control. If control is restored, getting into terminal mode science will probably take precedence over anything other than maintaining or improving control. Risks will be avoided due to the already precarious situation. The terminal mode would be very repetitive and would extend the period for which Phoenix returns weather info as long as possible. It is just not obvious Phoenix can handle more than that in Lazarus mode. In the best possible future, the lander's abilities are much diminished, and the ability to respond to conventional science commands is gone, so the commanding strategy is new. So beyond met-related data, expect maybe 30 or so repeated images per sol (sky & frost monitoring) from SSI, and maybe attempts with RAC and maybe attempts with MARDI. And frankly, even that will soon be overly ambitious.

I don't think the situation should be that big a surprise. Before landing, sol 150 was the conventional answer to "how long could the mission last". The power available hit the power needed curve at that time. Weather had been unseasonably favorable, so it looked like Phoenix could go longer before moving to desperation strategies like sacrificing instruments. When the weather turned, it was just to the seasonal pattern that should be in place by sol 150--cloudy and stormy. Sol 200 was never realistic, except maybe as the end of waking up in Lazarus mode for a month, in good circumstances. One factor, by the way, is that it is not just the low power, but also the cold. More power is needed to stay alive; much more was always needed compared to the rovers. Spirit has just set a new record low power level, but still maintained more activity compared to the previous low in winter. Why? It is warmer than in winter. And that is for a tropical location, with RHUs.

[climber]

...but Phoenix comes back thinking it is the day before launch (or some such) and wondering why the touchdown sensors indicate she has landed. And so, Phoenix realizes something has gone very wrong, and begins the Lazarus mode comm strategy.

Forget me for a very innocent question.
Spirit was nearly lost because her flash memory was full of informations gathered before landing that she didn't need anymore at that time.
Now Phoenix is fooled by the touchdown sensors, an information that, in absolute, could have been deleted.
What are the rationales for keeping this on bord? Can "we" build on these exemples to change, in the future, the post landing strategies regarding these issues?

[Deimos]

Now Phoenix is fooled by the touchdown sensors, an information that, in absolute, could have been deleted. What are the rationales for keeping this on bord?

My understanding is the physical touchdown sensor, not file clutter, is useful to Phoenix right now, to know that Lazarus mode is needed (as opposed to sitting and patiently waiting for launch or some other unproductive thing). This is not part of the problem, but of the solution.

[climber]

My understanding is the physical touchdown sensor, not file clutter, is useful to Phoenix right now, to know that Lazarus mode is needed (as opposed to sitting and patiently waiting for launch or some other unproductive thing). This is not part of the problem, but of the solution.

Thank you Mark & Emily. Very interesting to see how one (at least me ) could guess the oposite of the reality.