Having had to decide where to cut programs in my former career, I know how painful this is and my sympathies are with the managers who have to plan for this. My hope is that the political process will work at the last moment and we never have to learn what was on the chopping block.
In the charts showing the budgets for the Maven mission development and Curiosity rover operations in my post, Sequestration and Planetary Exploration, my spreadsheet software showed incorrect percentages (but correct dollar amounts). I've corrected these charts, and I thank Duane for pointing out the problem.
Casey Dreier (I presume this is the same Casey who is the Planetary Society's Advocacy and Outreach Strategist) in the comments points out that the sequester will be calculated from Fiscal Year 2012 budgets. NASA's overall budget for that year and this year are almost the same, so if NASA is given discretion on how to distributed the cuts, this may not make much of a difference. However, if the sequester is applied to each program, the news might be better for the planetary program if FY12 is the basis:
(All figures are in millions of dollars.)
If the planetary science program is cut less, though, other NASA programs likely will be cut more.