(Georgia Institute of Technology, 2006-08)
Alemany, Kristina; Wells, Grant William; Theisinger, John; Clark, Ian G.; Braun, Robert D.
Entry, descent, and landing (EDL) is a multidimensional, complex problem, which is
difficult to visualize in simple plots. The purpose of this work is to develop a systematic
visualization scheme that could capture Mars EDL trades as a function of a limited number
of variables, such that programmatic design decisions could be effectively made with insight
of the design space. Using the Mars Science Laboratory (MSL) as a basis, contour plots have
been generated for key EDL figures of merit, such as maximum landed elevation and landed
mass as a function of four input parameters: entry mass, entry velocity, entry flight path
angle, and vehicle L/D. Additionally, sensitivity plots have been generated in an attempt to
capture the effects of varying the fixed input parameters. This set of EDL visualization data
has been compiled into a Mars EDL handbook to aid in pre-phase A design space
exploration and decision making.
(Georgia Institute of Technology, 2005-07)
Hutchinson, Virgil L., Jr.; Olds, John R.; Alemany, Kristina; Christian, John A., III; Clark, Ian G.; Crowley, John; Krevor, Zachary C.; Rohrschneider, Reuben R.; Thompson, Robert W.; Young, David Anthony; Young, James J.
Tempest is a reusable crew exploration vehicle (CEV) for transferring crew from the
Earth to the lunar surface and back. Tempest serves as a crew transfer module that supports
a 4-person crew for a mission duration of 18 days, which consists of 8 days total transit
duration and 10-day surface duration. Primary electrical power generation and on-orbit
maneuvering for Tempest is provided by an attached Power and Propulsion Module (PPM).
Hydrogen (H2)/oxygen (O2) fuel cells and a high energy-density matter (HEDM)/liquid
oxygen (LOX) propellant reaction control system (RCS) provide power and reaction control
respectively during Tempest’s separation from the PPM. Tempest is designed for a lifting
entry and is equipped with parachutes for a soft landing.
Tempest is part of an overall lunar transportation architecture. The 60,731 lbs
combination of Tempest and the PPM are launched atop the notional Centurion C-1 heavylift
launch vehicle (HLLV) and delivered to a 162 nmi, 28.5º circular orbit. After separating
from the C-1 upper stage, the Tempest/PPM autonomously rendezvous with Manticore, an
expendable trans-lunar injection (TLI) stage pre-positioned in the current orbit, and
transfer to a lunar trajectory. After entering a 54 nmi polar circular lunar orbit, the
Tempest/PPM separate from Manticore. Tempest separates from the PPM and is ferried
to/from the lunar surface by Artemis, a reusable lunar lander. Upon return from the lunar
surface, Tempest reconnects with the PPM, and the PPM provides the trans-earth injection
(TEI) burn required to return to low earth orbit (LEO). Prior to atmospheric entry,
Tempest separates from the PPM and subsequently executes a lifting entry trajectory.
Crushable thermal foam attached to the lower surface of Tempest serves as an ablative
thermal protection system (TPS) and the impact absorber of the parachute landing.
Details of the conceptual design process used for Tempest are included in this paper. The
disciplines used in the design include: configuration, aerodynamics, propulsion, trajectory,
mass properties, environmental control life support system (ECLSS), entry aeroheating and
TPS, terminal landing system (TLS), cost, operations, and reliability & safety. Each of these
disciplines was computed using a conceptual design tool similar to that used in industry.
These disciplines were then combined and optimized for the minimum gross weight of the
Tempest CEV. The total development cost including the design, development, testing and
evaluation (DDT&E) cost was determined to be $2.9 B FY’04. The theoretical first unit
(TFU) cost for the Tempest CEV was $479 M FY’04. A summary of design disciplines as well
as the economic results are included.