(Georgia Institute of Technology, 2008-06-26)
Munk, Michelle Marie
This paper will explain the investment strategy, the role of detailed systems analysis, and the hardware and modeling developments that have resulted from the past 5 years of work under NASA's In-Space Propulsion Technology (ISPT) Program, Aerocapture investment area. The organizations that have been funded by ISPT over that time period received awards from a 2002 NASA Research Announcement. They are: Lockheed Martin Space Systems, Applied Research Associates, Inc., Ball Aerospace, NASA's Ames Research Center, and NASA's Langley Research Center. Their accomplishments include improved understanding of entry aerothermal environments, particularly at Titan, demonstration of aerocapture guidance algorithm robustness at multiple bodies, manufacture and test of a 2-meter Carbon-Carbon "hot structure," development and test of evolutionary, high-temperature structural systems with efficient ablative materials, and development of aerothermal sensors that will fly on the Mars Science Laboratory in 2009. Many of NASA's current programs are benefitting from the sustained ISPT support for Aerocapture, component technologies are mature enough to be infused on entry missions, and the aerocapture system technology is ready to be validated in flight.
(Georgia Institute of Technology, 2008-06-25)
Novak, Frank; Hutchinson, Mark; Mitchell, Michael; Munk, Michelle Marie; Parker, Peter
Each vehicle that lands on Mars provides a unique opportunity to study the atmospheric entry environment. Taking measurements of this environment will enable a better understanding of vehicle performance and design margins. Future vehicles will be able to take advantage of this improved knowledge in the forms of lower risk and possibly lower mass. The Mars Science Laboratory Entry, Descent and Landing Instrumentation (MEDLI) experiment will measure pressure and temperature on the protective heat shield during the MSL entry. The pressure distribution and Martian atmospheric data measurements are required to accurately determine the vehicle attitude (angles of attack and sideslip), and the dynamic pressure on the windward surface of the MSL heat shield. The pressure measurements are also used to provide Martian environment data and support computational fluid dynamics (CFD) code validation.
This paper will focus on the pressure measurement system, known as the Mars Entry Atmospheric Data System (MEADS), which consists of a flush orifice configuration connected by tubing to a specially ranged and selected pressure transducer and a custom-built signal conditioner, known as the Signal Support Electronics (SSE). The overall measurement requirements demand that the pressure measurement system be rugged and provide high rate, high accuracy output with small input power requirements, and the MEADS design meets those requirements. The pressure measurement system is being flight qualified using a protoflight approach, and will go through rigorous testing that consists of ambient and thermal calibrations, and environmental tests consisting of static acceleration, vibration, and thermal vacuum. The MEADS design approach, manufacturing experiences, and testing results will be discussed. As the system prepares for delivery in summer 2008, a key goal of the project is to serve as a pathfinder, such that every entry system of the future will be instrumented and will improve our knowledge of the critical entry environment.
(Georgia Institute of Technology, 2008-06-24)
Munk, Michelle Marie; Spilker, Thomas
Aerocapture has been studied for decades as a mass-efficient way to deliver orbiting spacecraft to planets or moons that have atmospheres. NASA's In-Space Propulsion Technology (ISPT) program sponsored detailed studies of robotic exploration missions using Aerocapture at Titan and Venus, in 2002 and 2004, respectively. The results of those studies are recalled in this paper, in light of current Flagship mission studies to these same destinations. Aerocapture is of enormous benefit for both missions, enabling multiplicative factors on delivered mass, compared to chemical propulsion or aerobraking capture techniques. The scientific return is significantly enhanced when aerocapture is used. Updates to our knowledge about Titan and Venus since these studies were conducted, are also included.