I don’t know about you, but I marvel at the successful landing on Mars by the unmanned craft Phoenix on 27 May. What an incredible feat of engineering.
This craft has taken 10 months to travel 420 million miles from Earth across hostile space. A host of different activities had to take place automatically, at precisely the right moment, with no possibility of human intervention to correct any faults to enable a landing to take place. If ever there was a need to get things right first time, this was it.
The craft approached Mars at some 13000 mph (21000 kph) and had to be slowed to a walking pace before settling on the planet’s surface. Firstly the heat shield had to protect the fragile craft from the fiery heat generated by entry into the Martian atmosphere. Next the parachute opened allowing the heatshield to be jettisoned and the landing ‘legs’ to be deployed. Next the ‘lander’ separated from the rest of the craft and the thrusters fired to allow the lander to touch down gently. Lastly the solar arrays unfolded to enable electricity to be generated so that the lander’s batteries could be charged.
26 separate explosive events (e.g. to jettison the heat shield, fire the thrusters) took place perfectly during the 7 minutes it took the craft to leave orbit around Mars and land on the planet’s surface.
I am in awe.