>1. Did you use constant atmospheric density, exponential density, or the
>standard Mars-GRAM2001 density ratio model combined with the Mars
>Thermospheric General Circulation model?

I used the MER-A atmospheric model which I believe comes from the Mars Global Circulation model. The MER-A model is specific to the location and time of MER-A's landing (4 Jan 2004). MarsGRAM is also derived from the Mars Global Circulation model.

>2. Did you adjust for latitude variations?

I used a 5x5 aeroid (Mars shape) with a J2 gravitational model both of which are latitude dependent. However the actual entry latitude, longitude and azimuth angles for Beagle 2 are unknown. Therefore I just used the entry coordinates for MER-B (Meridani). The error due to the guessed entry location is small compared to the error introduced by the unknown azimuth angle.

3. Did you adjust for time-of-year variation of atmospheric thickness?

That's built into the MER-A atmospheric model.

4. Did you account for compressibility effects at near-sonic and transonic velocity?

For the hypersonic velocities, I used a real gas model based upon a Martian atmospheric gas mix that's valid up to 20,000 deg.K. This model allows for single ionization (Beagle-2's trajectory was never close to double ionization). I used the real gas (NOT perfect gas) version of the Rankine-Hugoniot shock relations. The heat flux was calculated using the Fay-Riddel equation assuming a catalytic wall with an equilibrium boundary layer. Hypersonic aerodynamics was based upon the Modified Newtonian model with a Cp derived from a digital Mollier chart lookup. At Mach 1.7, I shifted over to sphere aerodynamics based upon a Mach and Reynolds number lookup table derived from experimental data. This model includes transonic and turbulent transition. Of course, alll of this was total over kill given the entry vector has to be guessed.

Gary