“The Lockheed Martin X-33 is an unmanned, sub-scale technology demonstrator suborbital spaceplane developed in the 1990s under the U.S. government-funded Space Launch Initiative program”. – Wikipedia

Photo: An Artist's Rendering Shows How Nasa's X-33 Technology Demonstrator, A Cost-Cutting Fully Reusable Single-Stage-To-Orbit Space Vehicle, Will Look Upon Completion. The 67 Foot-Long, 278,600 Pound, Twin Engine Space Vehicle, Capable Of Reaching Speeds In Excess Of Mach 15, Will Lead To The Construction Of A 127 Foot-Long, 2,186,000 Pound Version With Seven Engines And A 50,000 Pound Payload Capacity Called The “Venturestar”. (Photo By Nasa/Getty Images)

HRP-4C, a five-foot humanoid robot developed at Japan's National Institute of Advanced Industrial Science and Technology, sings and dances with performers at the Digital Contents Expo in Tokyo on October 17, 2010. The robot runs entertainment software called Choreonoid, a name formed from the words “choreograph” and “humanoid”. (Yoshikazu Tsuno/AFP)

Biologist Kelly Martin records her measurements of Electra, a 5 1/2 foot leatherback turtle nesting on the beach behind the Seminole Golf Club course in Juno Beach. Martin uses a red light which is invisible to turtles. (Photo by Greg Lovett/The Palm Beach Post)

Kevin and Merith Starren have their picture taken by Merith's brother Mark Ernst (R) and nephew Logan Ernst (L) in front of a 50-foot snowman named “Granddaddy” in Gilman, Minnesota, March 6, 2014. (Photo by Eric Miller/Reuters)

These pictures show a five-year-old boy who is already extremely comfortable around alligators. Blaise's dad T-Mike runs the Kliebert Gator Farm, the biggest and oldest in the world and which was started by his grandfather Harvey in 1957. Photo: T-Mike Kliebert and his son Blaise tackle Chinaman a 12 foot alligator in Hammond, Louisiana. (Photo by Barcroft Media)

Friends of Li Guojun drive a homemade tank-shaped vehicle in Kangping county, China. Li, a farmer who is a fan of tanks, spent six months with help from his friends to construct the almost 20-foot vehicle which weighs 2.5 tons. (Photo by Sheng Li/Reuters)

In this March 2, 2018 photo, an Andean man rests with his llama while tourists take in the natural wonder of Rainbow Mountain in Pitumarca, Peru. Tourists gasp for breath as they climb for two hours to the 16,404-foot (5,000-meter) peak in the Peruvian Andes, but stunned by the magical beauty that unfurls before them. (Photo by Martin Mejia/AP Photo)

Kashmiri children play with snow on a wooden foot bridge in the interiors of Dal Lake in Srinagar on January 16, 2017. A cold wave has further tightened its grip in Jammu and Kashmir, with most places in the state recording sub-zero temperatures. (Photo by Tauseef Mustafa/AFP Photo)