Design Issues for Space and Planetary Robots

1. Design Issues for Space and Planetary Robots • Who drives mission decisions in the UK? • Who funds space missions in the UK? • Know about where (and when) you are going! • Mission MASS, VOLUME, and POWER? • What rocket launchers are there? – (Europe) • ∆V, hyperbolic versus parabolic, EDLS? • Communications, tele-operation, autonomy. • Planetary robot systems and sub-systems. 29 CS36510

2. Know about where you are going! • Space can kill humans AND robots! • It’s not about if your robot will die? but about when your robot will die? All you can do is prolong the when! • Death can come at launch, cruise, EDL, during surface operations. • How far? What about radiation? How hot? How cold? Does is have an atmosphere? Is it solid, liquid or gaseous? Etc. (see Mars and Titan Links) 30 CS36510

3. Know about when you are going! For Mars: (Ls = Solar Longitude) 30 CS36510

4. Ideal Robot Mass, Volume, Power! • ZERO Mass • Lightweight, strong materials, but must NOT out-gas, or contaminate science instruments (e.g. no carbon fibre). Science mass versus engineering mass? • ZERO Volume • Must fit within Entry, Descent & Landing vehicle! • ZERO Power • Keeping electronics and battery warm consumes power. Budget your power consumption against surface operations. RTG versus solar panels? You don’t want to spend all your time charging batteries. 31 CS36510

5. Robot Volume – Beagle 2 ARM stowed 32 CS36510

6. Robot Volume - Sojourner stowed 33 CS36510

7. Sojourner Rover and Lander - 1997 34 CS36510

8. What rocket launchers are there? – (Europe) “The Ariane 5 ECA is the latest – and most Powerful member – of the Ariane 5 family, with a hefty payload lift capacity of 9,600 kg to geostationary transfer orbit (GTO). This performance ensures that Ariane 5 will be able to loft the heaviest telecom satellites in production or on the drawing boards, …” Launched from Kourou, French Guiana. 35 CS36510

9. What rocket launchers are there? – (Europe) Beagle 2 Launch Soyuz-Fregat The Fregat upper stage is an autonomous and flexible upper stage that is designed to operate as an orbital vehicle. It extends the capability of the lower three stages of the Soyuz vehicle. Payload - 4,100 kg. to 5,500 kg. Baikonur Cosmodrome, Republic of Kazakhstan. 36 CS36510

10. ∆V, Hyperbolic versus Parabolic, EDLS? • ∆V – Plan mission with as low a ∆V as is possible. Changing spacecraft velocity consumes fuel which you must take with you (more mass!). Use planet’s gravitational field to sling-shot your spacecraft to where you want to go. • Hyperbolic entry – landing site determined at launch. Parabolic entry is from orbit – better because you can plan where and when to land. • Entry, descent and landing (EDLS) - Dead-beat gas bag versus bouncing inflated bags versus retro-rockets? (these contaminate landing site). 37 CS36510

11. Communications, Tele-operation, Autonomy • What available communication resources are there. Earth based? Orbit based? • How many Light-Minutes between you and your robot? (8 minutes at beginning of Beagle 2 mission). • Tele-operate robot on the Moon – OK, Mars – NO. • What degree of autonomy should you (dare you!) provide? Navigation? Sample Acquisition? Repair? 38 CS36510

12. Planetary Rover Systems (MER example) 39 CS36510

13. System • Management • Power • Planning etc. Planetary Rover Sub-Systems (simplified overview) Software – Computer architecture design decisions? Control & Data Processing Comms. Rover Navigation ARM Kinematics & Control Instruments Antenna Chassis Manipulator Solar Array, RHU etc. Look at these areas Hardware – Mechatronic design decisions? 40 CS36510