On Sat, Jan 27, 2018 at 04:03:42AM -0500, Caleuche wrote:
> So, taking the same good ship Hamiltonian, this time in low orbit of
> Home, and applying a deorbit impulse of 800 m/s, and modeled as a
> conical starship of about 800 Dtons, with a height to radius ratio
> of 10:1 with a frontal surface area of 328.6 m^2, and a drag
> coefficient of 0.22 and a mass of 75 tons (that's very light, I only
> modeled the outer hull, which has implications for the terminal
> phase of reentry) the reentry looks something like this:

Is that assuming an uncontrolled entry?  I would expect most ships
attempting such a maneuver to have at least some aerodynamic
maneuvering capability, and choose their altitude (and consequently
deceleration rate) during various stages of the procedure.

Also yes, 75 tonnes is very light.  800 dton ships in Traveller often
have masses more like 7500 tonnes.  The main effect would be that peak
deceleration would occur on the order of 30-40 km lower in the
atmosphere.  That's somewhat unfortunate given that the current
profile has the ship still moving with more than half its initial
speed at those altitudes.  They will want a shallower angle of descent
(or active deceleration with thrusters), lest substantial lithobraking
occur.

> I can also imagine situations in which starships with 1 or 2 g
> acceleration could get themselves in trouble fuel skimming a large
> enough gas giant.

Given the thermodynamics involved, meteoric gas giant skimming seems
pretty ridiculous even for Traveller technology anyway.

- Tim