According to the announcement, Dawn had already stopped being able to communicate due to having exhausted its fuel at the time I wrote the previous post, about the end of the Kepler mission, but I guess only the team knew that at the time, or perhaps not even them just yet. They were quick to make the announcement once they did know though, since scheduled communications were missed on October 31 and November 1 and the announcement came on that same day, November 1.
Once again, the event was entirely expected, though no less sad because of that. In fact, the thrusters managed to keep operating until the very end of the estimated period, the announcement about the imminent end of the mission published in July stating that hydrazine would run out between August and October, with the more recent estimate, from September, which had narrowed the range to mid-September to mid-October, actually proving to have been too conservative.
I do look a bit oddly at the article about the coincidence that Dawn and Kepler were about to run out of fuel at about the same time posted on October 29, since it was known since October 19 that Kepler had switched itself to its no-fuel-use sleep mode and the reason for it was perfectly clear. But I guess the difference is that they could know that about Kepler and perhaps there were still some options, however extraordinarily unlikely, to consider, other uses that could be found for the spacecraft even without fuel, while in case of Dawn exhausting the fuel for its thrusters makes it unable to communicate right away, leaving no options whatsoever.
Unfortunately, if TESS can be said to be something of a replacement at least for Kepler’s K2 mission, albeit one with a much shorter attention span, there is nothing of the sort for Dawn. With a few exceptions still made for Jupiter, we just stopped looking beyond Mars, and after Juno will stop operating as well, we won’t have anything at any solar system body beyond Mars at all. And with New Horizons and the Voyagers set to run out of power at some point in the next decade, we’ll be left with nothing out there at all, the lack of even any projects going beyond Jupiter ensuring that nothing functional will be out there again for decades to come. Things we, as a species, could plan for in the 1960s and actually do in the 1970s and 1980s apparently can’t be done anymore…
But speaking of going silent and Mars and what we apparently still care to do, since InSight is scheduled to land there later this month, Opportunity is unfortunately still silent, nearly five months after last contact, and the 45-day period during which it was considered that contact was most likely to be restored if the rover had survived the dust storm has ended. However, the page about the recovery efforts was updated on October 29 with a message stating that the current strategy for contacting the rover will continue for the foreseeable future, because it is possible that the silence is due to the solar panels being covered by dust after the storm and this time of year has previously brought dust clearing events, a reassessment of the situation, I assume in case there will still be no contact by then, being tentatively scheduled for January. So the situation looks bad and I guess the announcement about the end of that mission as well is pretty much ready by now, but there may be some shred of hope yet and they won’t give up for at least the next couple of months.