Russian cosmonaut Alexander Skvortsov, Expedition 40 flight engineer, attired in a Russian Orlan spacesuit, participates in a session of extravehicular activity (EVA) in support of science and maintenance on the International Space Station on August 18, 2014. During the five-hour, 11-minute spacewalk, Skvortsov and cosmonaut Oleg Artemyev (out of frame) deployed a small science satellite, retrieved and installed experiment packages and inspected components on the exterior of the orbital laboratory. (Photo by NASA)

Astronaut Donald R. Pettit would often rig an array of as many as six cameras in the cupola windows and set them all to fire continuously for events such as sunsets, which only last around seven seconds on the ISS. (Photo by Donald R. Pettit)

A man rides a motorcycle along a street in the snow in Altay, Xinjiang Uighur Autonomous region, February 9, 2016. (Photo by Reuters/Stringer)

Eurocopter's X³ high-speed hybrid helicopter demonstrator performs, September 6, 2010. The Eurocopter X³ (X-Cubed) is an experimental high-speed compound helicopter developed by Eurocopter (now Airbus Helicopters). A technology demonstration platform for Eurocopter “high-speed, long-range hybrid helicopter” or H³ concept, the X³ achieved 255 knots in level flight on 7 June 2013, setting an unofficial speed record for a helicopter. (Photo by Reuters/HO/Eurocopter/Penna)

Handout grab taken from YouTube of Commander Chris Hadfield who has said goodbye to life on the International Space Station by making a cover version of David Bowie's Space Oddity. Issue date: Monday May 13, 2013. (Photo by Commander Chris Hadfield/YouTube/PA Wire)

Yak near Yamdrok lake, Tibet. It is a long-haired bovinae found throughout the Himalayan region of south Central Asia, the Tibetan Plateau and as far north as Mongolia and Russia. The Tibetan economy is dominated by subsistence agriculture. Due to limited arable land, the primary occupation of the Tibetan Plateau is raising livestock, such as sheep, cattle, goats, camels, yaks, dzo, and horses. The Tibetan yak is an integral part of Tibetan life. (Photo by Dennis Jarvis)

Behaviour winner; Courting Royals: two royal terns in courtship display by Kristian Bell. Another beautiful morning on a beautiful beach on the Gulf Coast of Florida seemed to prompt these two royal terns to commence an intricate courtship dance. The photograph was taken with a Canon 300mm lens and 2x extender. (Photo by Kristian Bell/Deakin University/Royal Society Publishing Photography Competition 2018)

A meteor streaks over the sky during the Perseid meteor shower at the Maculje archaeological site near Novi Travnik August 12, 2014. According to NASA, the annual Perseid meteor shower reaches its peak on August 12 and 13 in Europe. The fireballs from the meteorites are fast and plentiful, although a nearly full moon (Supermoon) makes it difficult to view them this year, the agency adds. (Photo by Dado Ruvic/Reuters)