Given a limited and fluctuating budget, the NASA administrator and his Soviet counterpart ( Sergei Korolev?) had to recruit and train astronauts, design spacecraft, and assign manned and unmanned missions.

FORBES: The Return of "Buzz Aldrin's Race into Space" Game

Some satellite developers are beginning to design spacecraft so that sensitive instruments are located towards the back of the satellite to minimise any risk of impact damage, and the side facing away from earth is shielded to protect it from meteoroids.

ECONOMIST: Orbital debris

"The fact that the mission is still on track is a tribute to the robustness of the spacecraft and a mission design that included planning for adversity, " says Dr Robert Farquhar.

BBC: Probe nears its rocky target

Stern and his colleagues are inventorying the Pluto system with Hubble to get a better handle on the risks New Horizons faces, and to help design the safest possible trajectory for the spacecraft.

MSN: New Pluto moon hints at perilous journey for spacecraft

The same design of instrument was used on the Lunar Prospector spacecraft that discovered ice in the shadowed regions of the Moon's poles in 1998.

BBC: Ice reservoirs found on Mars