Something that bothered me about that far off picture of MER-B's backshell was its color. The color of the backshell on the martian surface was tan/orange with bits of white. The photo of the backshell while MER was being constructed shows it as uniformly white:
http://marsrovers.jpl.nasa.gov/mission/spa..._aeroshell.htmlThe EDL Critical Design Review document shows the peak heat flux on the backshell to be under 2 watts/cm^2. I initially asked myself: Why did it discolor so much? Then I reread the JPL URL above and it said:
"Also, instead of being painted, the backshell will be covered with a very thin aluminized mylar blanket to protect it from the cold of deep space. The blanket will vaporize during Mars atmospheric entry."
This actually solves two mysteries at once. I know that the backshell TPS material is SLA-561S which is an orange colored spray on ablator. The mylar blanket must be the reason why the backshell was white instead of orange for the above URL. Mylar would have vaporaized at under 2 watts/cm^2. The bits of white are probably pieces of mylar that didn't vaporize away during entry. I hope they get a close look at the backshell.
Gary