ARLISS 2002 CanSat Experiment

1. ARLISS 2002 CanSat Experiment 8/2-3/2002 University of Tokyo

2. Overview • Three Open Class CanSats developed by three teams in the Graduate School Class “Special Lecture on Spacecraft Design” by Prof. Nakasuka • Objectives: (1)Satellite design/fabrication/test/ operation, and (2)project management/team work • Participation in “Come back competition” • Each team consists of 7-8 students • Development period: late April to mid July • Budget: $1,600 per team

3. System Overview (Common) Ground Station CanSat parafoil Downlink GPS antenna antenna GPS antenna transceiver servomotor GPS data transceiver Ground Station PC Control signal CPU modem Data (GPS, Control status) memory

4. Pre-experiment in Japan • Watarase Balloon Experiment (July 17) • Final exam of the class • Unmanned Helium balloon lift up one CanSat to 200 m and release it using timer mechanism • Best result: 14 m away from the target point • Each team obtained various skills and expertise • Parafoil string length adjustment • Tuning of control parameters • Folding method of parafoil • etc.

5. Team 1 Masaki Nagai Ryu Funase Mitsuhisa Ikeda

6. Cansat of Team 1 (Body part) • It has 2 servomotors to control parafoil variously. • Height 170mm • Diameter 144mm • Weight 1.05kg • Material Al, steel GPS antenna 2 Servo motors behind this line Main board Micro switch Battery Strings of parafoil transceiver Arm of human being

7. Cansat of Team 1 (Parafoil) In order to unfold the parafoil well, and keep the shape of parafoil, • Top and bottom surface is made with very soft material. • Elastic iron bones are attached. • The rib is made with stiff material. Top: soft Iron Bone Rib: stiff Bottom: soft After landing

8. Result1 (team1) • Cansat was influenced by the wind . • Cansat was always trying to come back to the target point. • At last, near the ground, Cansat could go back to the target. But it was too far.

9. Result2 (team1) • Cansat was surely tried to control. • But when it tried to go against the wind, it changed the velocity direction rapidly → it could not approach the target. • Parafoil had a bias to turn right. • The control input was too small to overcome the bias and the wind

10. Result3 (team1) • At last, near the ground, Cansat managed to go back to the target. But because of the bias to turn right and the small control, it could not go back straight.

11. Conclusion (team1) • The result of this competition • 3010m from the target. • We could receive Downlink data. • CanSat was surely trying to control properly. • We could follow the flying CanSat using downlink GPS data. • In order to improve the Cansat: • Adjust the length of the strings of the parafoil using Flight Model CanSat. • Enlarge the control gain.

12. Team 2 Sanae Ishikawa Chikara Ohishi

14. Structure The structure is composed of stainless beams and orange acrylic boards. They are connected by nylon binders. This structure is very flexible and prevents internal components from suffering damages.

15. Side view Servo motor GPS antenna GPS receiver Sensor board Micro switch Main board Motor battery Main battery Transceiver

16. Side view & Bottom view Side Bottom Antenna Transceiver Main switch Shield

17. Launch site Wind direction Result Our Cansat landed 3290m away from the target point. Due to the power line problem, the electric system was not functioned well. But, the parafoil system seemed to work well.

18. Team 3 Yuya Nakamura Satoru Hori Yutaka Komatsu

19. Our Result • Our CanSat came back to the very near point from the target!!! Target

20. Photos at Landing Point

21. This is the flight record of our CanSat. (Final Approach Phase) Landing Point Release Point (A) B Launch Site 45m! Target C Target Flight Record

22. Altitude Record This is the altitude record of our CanSat. GPS 3554.3 m 11661 ft Barometer Flight Time 23:46

23. Control Method • Control Phase 1 • The CanSat Sails straight to the target after the release. • Control Phase 2 • After the CanSat gets 20m away from the target, it turns around the target in a circle and descents. • Control Phase 3 • When the CanSat descents to the altitude of 30m, it begins to head toward the target again, which is a final approach.

24. Control Record 1 We used servo motor to control the direction of our CanSat. This is the control record. (5deg is the default motor angle.) B Control Start (A) C Launch Landing

25. What Happened at Each Phase? • A-B (Control is maximally right turn) • Try to turn right to go to the target, but strong wind blew away our CanSat toward downstream. • B-C (Maximally right turn with periodical left) • Almost same as A-B phase, but sometimes the velocity direction surpass the switching direction when left turn command is periodically given. • C-Landing (Control force >Wind, and come back) • Control force overcame the wind force, and proper control is made, at the altitude less than 1995m AGL.

26. Control Record 2 Target

27. View of Our CanSat Parafoil GPS Antenna Covering Net Micro Switch CMOS Camera Unit (Treva) GPS Receiver Battery Box

28. Our Parafoil We made 8 parafoils. The No.7 parafoil has the best performance, so we used it for the rocket launch. No.5 No.6 No.8 No.7

29. Image Capture Unit (Treva) We loaded the small CMOS camera called “Treva”. It is normally used for mobile phones. We tried to take 16 pictures from up in the sky, but this time we only got 2 pictures. The reason of that may be the shock of the release. Treva (by Kyocera)

30. Photos the Treva Took in the Sky Unfolded Parafoil Black Rock Desert GPS antenna code & Aluminum plate