(Georgia Institute of Technology, 2008-06-26)
Korzun, Ashley M.; Smith, Brandon P.; Yu, Chi-Yau; Hartzell, Christine M.; Hott, Kyle B.; Place, Laura A.; Braun, Robert D.; Martinelli, Scott K.
Mars Gravity Biosatellite is a novel program aimed at providing data on the effects of partial gravity on mammalian physiology. A collaboration between MIT and Georgia Tech, this student-developed free-flyer spacecraft is designed to carry a payload of 15 mice into low Earth orbit, rotating to generate accelerations equivalent to Martian gravity. After 35 days, the payload will re-enter the atmosphere and be recovered for study. Having engaged more than 500 students to date in space life science, systems engineering, and hardware development, the Mars Gravity Biosatellite program offers a unique, interdisciplinary educational opportunity to address a critical challenge in the next steps in human space exploration through the development of a free-flyer platform for partial gravity science with full entry, descent, and landing (EDL) capability.
Execution of a full entry, descent, and landing from low Earth orbit is a rare requirement among university-class spacecraft. The EDL design for the Mars Gravity Biosatellite is driven by requirements on the allowable deceleration profile for a payload of de-conditioned mice and maximum allowable recovery time. The 260 kg entry vehicle follows a ballistic trajectory from low Earth orbit to a target recovery site at the Utah Test and Training Range. Reflecting an emphasis on design simplicity and the use of heritage technology, the entry vehicle uses the Discoverer aeroshell geometry and leverages aerodynamic decelerators for mid-air recovery and operations originally developed for the Genesis mission. This paper presents the student-developed EDL design for the Mars Gravity Biosatellite, with emphasis on trajectory design, dispersion analysis, and mechanical design and performance analysis of the thermal protection and parachute systems. Also included is discussion on EDL event sequencing and triggers, contingency operations, the deorbit of the spacecraft bus, plans for further work, and the educational impact of the Mars Gravity Biosatellite program.
(Georgia Institute of Technology, 2008-06-24)
Otero, Richard; Grant, Michael; Steinfeldt, Brad; Braun, Robert D.
The Planetary Entry Systems and Synthesis Tool (PESST) has been under development at the Space Systems Design Laboratory (SSDL) for several years. This framework has the capability to estimate the performance and mass of a hypersonic vehicle using user-defined geometry, hypersonic aerodynamics, flight mechanics, selectable guidance, thermal response and mass estimation. Earth and Mars atmospheres are preloaded with the ability to also use either user-defined or GRAM atmospheric models. Trade studies can be performed by parameter sweeps to gain an excellent understanding of the design space for conceptual studies. This framework is broadly applicable to conceptual studies of EDL, aerocapture and precision and/or pin point landing systems.