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