(Georgia Institute of Technology, 2006-09)
Christian, John A., III; Wells, Grant William; Lafleur, Jarret M.; Manyapu, Kavya; Verges, Amanda; Lewis, Charity; Braun, Robert D.
The human exploration of Mars presents many challenges, not least of which is the task
of entry, descent, and landing (EDL). Because human-class missions are expected to have
landed masses on the order of 40 to 80 metric tons, significant challenges arise that have not
been seen to date in robotic missions. This study provides insight into the challenges
encountered as well as potential solutions through parametric trade studies on vehicle size
and mass. Aerocapture and entry-from-orbit analyses of 10 and 15 m diameter aeroshells
with a lift-to-drag ratio of 0.3 or 0.5 were investigated. Results indicate that in the limit, a
crew capsule used only for descent could have an initial mass as low as 20 t. For larger
landed payloads, such as a 20 t surface power system, a vehicle with an initial mass on the
order of 80 t may be required. In addition, no feasible EDL systems were obtained with the
capability to deliver more than approximately 25 t of landed payload to the Mars surface for
initial masses less than 100 t. This suggests that an aeroshell diameter of 15 m may not be
sufficient for human Mars exploration.
(Georgia Institute of Technology, 2006-02)
Wells, Grant William; Lafleur, Jarret M.; Verges, Amanda; Manyapu, Kavya; Christian, John A., III; Lewis, Charity; Braun, Robert D.
Near-term capabilities for robotic spacecraft include a target of landing
1 - 2 metric ton payloads with a precision of about 10 kilometers, at moderate
altitude landing sites (as high as +2 km MOLA). While challenging, these
capabilities are modest in comparison to the requirements for landing human
crews on Mars. Human Mars exploration studies imply the capability to safely
land 40 - 80 metric ton payloads with a precision of tens of meters, possibly at
even higher altitudes. New entry, descent and landing challenges imposed by the
large mass requirements of human Mars exploration include: (1) the potential
need for aerocapture prior to entry, descent and landing and associated thermal
protection strategies, (2) large aeroshell diameter requirements, (3) severe mass
fraction restrictions, (4) rapid transition from the hypersonic entry mode to a
descent and landing configuration, (5) the need for supersonic propulsion
initiation, and (6) increased system reliability. This investigation explores the
potential of extending robotic entry, descent and landing architectures to human
missions and highlights the challenges of landing large payloads on the surface
of Mars.