1. 1 Weekly Summary Asteroid Sample Return Spring Semester March 5, 2008 Ashley Chipman

2. 2 Last Week GN&C –Wrote matlab program to iterate approach trajectory to determine: Delta v’s Time on approach orbit Impact accelerations –Researched star tracker w/info from Steve –Gave initial weight estimates for all sensors to Structures Propulsion –Picked quantity (4) and arrangement (about center of mass) of hydrazine rocket clusters –Determined Isp of 220 to 230s –Identified mass vs. fuel relations with rocket equation –Identified means of finding required fuel volume for Delta-v maneuvers –Researched fuel tanks Structures –Trade study on driving force for landing spikes –Continue ANSYS work on landing stresses –Determine materials for structure of aircraft for trade study.

3. 3 Outstanding Issues Further spike testing (frozen) Attitude Control Fuel

4. 4 Next Week GN&C –Finalize star tracker, altimeter, and imu that will be used to obtain weights –Work w/other groups to finalize approach and altitude of vertical drop –Start high level control systems architecture Propulsion –Identify specific thrusters from distributors –Incorporate available thrusters into Matlab design code & select based on force reqs –Consider angular velocity capabilities of attitude thrusters –Look into methods of maintaining center of mass during fuel tank depletion –Investigate propulsion schematic (pyro-valves, latch-valves, solenoid-valves, service valves, pressure transducers, orifices, cryo-joints, and filters) Structures –Different layouts for spacecraft structure (body and landing) –Thermal calcs and C.G. approximations –Further testing for spikes Nail 3” long and 1/4” diameter (frozen ground)

5. 5 Updated Schedule

6. 6 Details of Attachment Mechanical Attachment –Hilti Gun DX E72 2.0 kg (assuming necessary mechanics similar in wt) Highest power.22 –Wt of 40 grains –Muzzle velocity of 2020 ft/s –Results: 2.59 g and 615.7 m/s, yields momentum of 1.595 N  s Delta V from ignition of V=4 (1.595/wt) –Final Specs 14 kg and delta V between 0.008 and 0.012 (750 kg and 500 kg wt)