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Daniel Guggenheim School of Aerospace Engineering

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Author: Braun, Robert D. × End date: 2009 × Start date: 1980 × Item Type: Publication × search.filters.applied.f.isSeriesOfPublicationTitle: International Planetary Probe Workshop (IPPW) ×

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Now showing 1 - 6 of 6
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Entry, Descent, and Landing System Design for the Mars Gravity Biosatellite

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.

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Evaluation of the Mars Pathfinder Parachute Drag Coefficient

2007-06 , Verges, Amanda M. , Braun, Robert D.

Flight reconstruction of the successful landing of the Mars Pathfinder (MPF) mission was performed after landing. During development of the Mars Exploration Rover mission, the MPF parachute drag coefficient was re-examined. Using radar altimeter data, it was determined that the MPF parachute drag coefficient was 0.4133 (based on the parachute’s nominal area), with a 3-sigma uncertainty of 0.0514. This study assumed a quasi-steady state terminal descent, neglecting the effect of the parachute’s continued deceleration. In the present study, the MPF parachute drag coefficient is evaluated using the same radar altimeter data but taking into account the fact that the MPF parachute continued to decelerate during its terminal descent. This deceleration is also evaluated from the radar altimeter data. The present investigation yields a drag coefficient of 0.4419, with a 3-sigma uncertainty of 0.0549. Taking into account the acceleration effect increases the reconstructed value of the drag coefficient by approximately 7 percent. The difference in drag coefficients determined from the two reconstructions is relatively large because the deceleration being experienced by the system at this time is approximately 0.240 m/s2, a relatively significant value in comparison to the acceleration of gravity on Mars (3.7245 m/s2).

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Introducing PESST: A Conceptual Design and Analysis Tool for Unguided/Guided EDL Systems

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.

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A Survey of Ballute Technology for Aerocapture

2005-06 , Rohrschneider, Reuben R. , Braun, Robert D.

Ballute aerodynamic decelerators have been studied since early in the space age (1960’s), being proposed for aerocapture in the early 1980’s. Significant technology advances in fabric and polymer materials as well as analysis capabilities lend credibility to the potential of ballute aerocapture. The concept of the thin-film ballute for aerocapture shows the potential for large mass savings over propulsive orbit insertion or rigid aeroshell aerocapture. The mass savings of this concept enables a number of high value science missions. Current studies of ballute aerocapture at Titan and Earth may lead to flight test of one or more ballute concepts within the next five years. This paper provides a survey of the literature with application to ballute aerocapture. Special attention is paid to advances in trajectory analysis, hypersonic aerothermodynamics, structural analysis, coupled analysis, and flight tests. Advances anticipated over the next 5 years are summarized.

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Entry, Descent, and Landing System Design for the Mars Gravity Biosatellite

2008-06 , Korzun, Ashley M. , Smith, Brandon P. , Hartzell, Christine M. , Yu, Chi-Yau , Place, Laura A. , Martinelli, Scott K. , Braun, Robert D. , Hott, Kyle B.

Execution of a full entry, descent, and landing (EDL) from low Earth orbit is a rare requirement among university class spacecraft. Successful completion of the Mars Gravity Biosatellite mission requires the recovery of a mammalian payload for post-flight analysis of the effects of partial gravity. The EDL design for the Mars Gravity Biosatellite is driven by requirements on the allowable deceleration profile for a payload of deconditioned 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, the de-orbit of the spacecraft bus, plans for further work, and the educational impact of the Mars Gravity Biosatellite program.

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Development of a Planetary Entry System Synthesis Tool for Conceptual Design and Analysis

2005-06 , Kipp, Devin M. , Dec, John A. , Wells, Grant William , Braun, Robert D.

A Planetary Entry Systems Synthesis Tool, with applications to conceptual design and modeling of entry systems has been developed. This tool is applicable to exploration missions that employ entry, descent and landing or aerocapture. An integrated framework brings together relevant disciplinary analyses and enables rapid design and analysis of the atmospheric entry mission segment. Tool performance has been validated against Mars Pathfinder flight experience and has direct relevance to future NASA robotic and human space exploration systems.

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