I'm guessing that without mobility, they won't be able to get Spirit angled well for winter solar energy gathering and so Spirit probably won't survive this winter. Opportunity, unless something unforseen happens, should survive the winter and reach Endeavour crator in a little more than a year from now.
The engineering team that designed and built these robots really are to be congratulated. In an environment as hostile as Mars these two rovers have defied all the odds and delivered more science than anyone would have dared imagine.
If they are coming to their ends, it will absolutely be in triumph.
Still, I get a bit misty thinking about it.
