2. Aerodynamics
2.1 Atmospheric Entry Aerothermodynamics and Aerodynamic Stability
Santosh J Kuruvilla
Abstract
The configurations of the vehicles entering the atmospheres of Earth and Mars are described. The Habitat is a hybrid of a biconic entry vehicle and a lifting body, this provided the required L/D ratio for the aerocapture maneuver performed on Mars entry while limiting the maximum deceleration experienced by the astronauts, this also satisfied the volume requirements of the mission. The Earth Return Assembly is cylindrical in shape, with a flared aft section, this vehicle did not require the high L/D required for the Habitat, since the allowable deceleration on this vehicle was higher due to the lack of human occupants; the volume requirements were also satisfied. The Crew Transfer vehicle is a Lifting body, this was deemed necessary because, on earth entry the atmospheric entry velocity was much higher, this caused an increase in the convective heating subject on the vehicle. This shape also allowed the occupants to decelerate at a lower rate and fly towards a suitable landing zone on entry.
2.2 Atmospheric Trajectories
Nicholas H. Saadah
Abstract
We create an algorithm which calculates aerodynamic and gravity forces on a vehicle as it propagates through the atmosphere of a planet, and use the algorithm for trajectory optimization purposes. We present entry conditions for three scenarios, aeroentry, aerocapture and aerobraking, into the atmospheres of Mars and Earth as needed for the design of a manned mission to Mars. Two constraints, maximum g-loading on the spacecraft and roll angle, are adjusted to widen the entry corridor to 2°.
2.3 Descent Stage
Jeremy Davis
Abstract
Design of a descent stage for an entry or re-entry mission is governed mainly by constraints. Few variables are left to optimization rather than being fixed by constraints such as g-loading, altitude and velocity requirements. The constraints that govern the values presented in this report are as follows: For the supersonic parachute, the deployment is constrained by a Mach 3 deployment velocity, a Mach 1 constraint to end the deployment, and the size of the parachutes is limited by the g-load constraints. For the subsonic parachutes, a deployment velocity of Mach 1 limits the maximum altitude for deployment, the time required to reach terminal velocity limits the maximum cut altitude (to release the parachutes) and g-load constraints affect the size of the parachutes and the terminal velocity. For the retro rocket engine, the touchdown velocity requirements affect thrust and propellant needed and fixes the time of burn. From this, it is obvious that there is little room to optimize but makes it challenging for the descent analyst to fit all the pieces of the descent stage together.
2-A