Science Behind the Photo #35

Shuttle landings

Perhaps unsurprisingly, the space shuttle takes off like a rocket. The orbiter has rocket  boosters in addition to its main engines, which are used for launch before they detach and drop back down to Earth – these falling boosters are strategically aimed towards the ocean, so they land relatively unharmed and can be retrieved for use in a future mission.

As explained by NASA engineers, the rocket boosters “burn for about two minutes” before they are released from the shuttle. Then, “the shuttle’s main engines fire for about another six minutes” before the external fuel tank is released in a similar way to the boosters. It is not long after this happens that the shuttle and crew reach their goal: orbit around the Earth.

The image above shows the end of a mission: not the launch, but the landing. To leave orbit, the crew on board the shuttle fire the engines briefly to change the craft’s speed and thus begin falling back to Earth. The shuttle re-enters our atmosphere and glides in for a runway landing, as show above. Also visible is a vapour trail known as a contrail; a trail of condensed water vapour caused in the engines of aircraft. These can take the form of microscopic water droplets or tiny ice crystals as the hot exhaust air from the engine cools rapidly upon contacting the cooler air outside the craft.

This is a particularly poignant image as it was taken during the 33rd and final landing of Atlantis in July of 2011, the final US shuttle mission.  A group of high-profile former NASA astronauts including Neil Armstrong, James Lovell and Eugene Cernan rallied hard against the ending of the shuttle programme in an open letter to President Obama penned  2010, in which they state that “America must decide if it wishes to remain a leader in space”, as, without a manned space programme, the USA is “on a long downhill slide to mediocrity”.

Image: NASA’s Space Shuttle Gallery

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