(Georgia Institute of Technology, 2005-11-10)
Scher, Michael D.; North, David
The Space Propulsion Sizing Program is an advanced tool to facilitate vehicle design and
broad system-level trade studies. It was designed to provide a simple and reliable means
for rapid propulsion trade studies during the conceptual design phase. This is
accomplished through a combination of mass estimating relationships, bottom-up
calculations, and historical data to size several vehicle subsystems. Microsoft Excel and
Visual BASIC were selected as the medium for the application of these methods.
Through the versatility of Visual BASIC, several output modes are available for the
vehicle mass breakdown and geometry estimates. The capability and reliability of this
unique tool has been demonstrated by comparing estimates to real vehicles.
(Georgia Institute of Technology, 2005-11-09)
Reeves, David M.; Scher, Michael D.; Shidner, Jeremy; Thomas, Paige D.; Bucher, Dean; Roithmayr, Carlos
Discussion of various system architecture tools and assumptions available to modify existing architectures for new requirements and mission objectives. This study started from proven Apollo concept and adjusted it for new requirements and mission objectives. New technologies were included to decrease size and cost. A crew size trade study is presented to demonstrate how mass size, propulsion size, and trajectory are calculated for an unmanned and up to four man crew in lunar exploration missions
(Georgia Institute of Technology, 2005-11-09)
Reeves, David M.; Scher, Michael D.; Wilhite, Alan W.; Stanley, Douglas O.
The 1962 Apollo architecture mode decision process was revisited with modern analysis
and systems engineer tools to determine driving selection criteria and
technology/operational mode design decisions that may be used for NASA’s current
Space Exploration program. Results of the study agreed with the Apollo selection of the
Lunar Orbit Rendezvous mode based on the technology maturity and politics in 1962.
Using today’s greater emphasis on human safety and improvements in technology and
design maturity, a slight edge may be given to the direct lunar mode over lunar orbit
rendezvous. Also, the NOVA direct mode and Earth orbit rendezvous mode are not
competitive based any selection criteria. Finally, reliability and development, operations,
and production costs are major drivers in today’s decision process.