Saturday – April 19th, 2008
Joseph Farrell – U of A
Junior in Aerospace Engineering at University of Arizona
Location of internship – Raytheon Missile Systems
Project Title – “Robotic Lander Design and Development”
Mentor – Jim Head (with assistance from Raytheon Engineers, and UA Faculty/Students)
Joseph Farrell
Analysis of a Lunar Surface Return (LSR) report and excel spreadsheet (‘06-’07 Space Grant Report). Review of the Boomerang Report (NASA).
Analysis of Lander thruster configurations. Other Tasks:• Organization and summarization of the Goddard
Space Flight Center Program Listing.• Basic Matlab proficiency.• Preliminary Honeycomb Analysis (See Chris
Rogers’ presentation).
Joseph Farrell
Joseph Farrell
Image taken from the Boomerang Report
Focus of Analysis
LSR Report details a round-trip mission to the moon to collect a payload of moon material and bring it back to Earth.
“Boomerang” Report details a functionally similar mission.
Tasked with making the spreadsheet “close” ◦ Enough Net Delta V available for both the
ascent and landing stages◦ Positive lift margin for the launch stage
Goal was to optimize the spreadsheet to function with the parameters of the “Boomerang” Report.
Joseph Farrell
Analysis parameters:- Fixed Launch Vehicle- Landing Stage • Between 1-4 pairs of fuel
tanks• Variable SRM Engine (Star #
ATK Motor)
- Lunar Ascent Stage (LAV)• 2 Stage Launch
Stage 1 – Variable SRM Engine (Star # ATK Motor)
Stage 2 – Variable SRM Engine (Star # ATK Motor)
Joseph Farrell
Ultimately concluded that spreadsheet can not ‘close’.
“Boomerang” assumptions include the Lunar Lander providing delta V for landing and ascent.
LSR Report / Spreadsheet lacks this assumption.
Joseph Farrell
Presented with four potential thruster configurations for landing a Planetary Lander with a vertical delta V=250m/s:Configuration 1: 4 Divert Thrusters, 8 ACS
Thrusters on deck.Configuration 2: 4 Divert Thrusters, 6 ACS
Thrusters on poles.Configuration 3: 2 Lateral and 2 Downward
Divert Thrusters , 8 ACS Thrusters on deck.Configuration 4: 2 Lateral and 2 Downward
Divert Thrusters, 6 ACS Thrusters on poles.
Joseph Farrell
Joseph Farrell
Task was to judge/analyze different configurations based on (only a few listed):
- Braking Time - Fuel usage - Correction time for 10ms
Divert misfire
- Ability to compensate for C.G. drift
- Misfires about the X, Y, and Z axes
- More…
Joseph Farrell
VerticalHorizontal
Error bars compensate for C.G. Drift
Configuration 3 chosen to be optimum configuration – 2 Down, 2 Lateral Divert Thrusters, 8 ACS Thrusters on deck.
Joseph Farrell
Overall, my experience at Raytheon has been a very positive one.
Gained valuable insight into team-work and solitary analysis.
Better understanding of the practical work that goes with the title of an “engineer”.
Thanks!!
Joseph Farrell