A prototype of a new nano spaceship is displayed during a press conference held by Israel's Space IL organisation on December 8, 2011 in Ehud, Israel. Israeli President Shimon Peres participated in the event unveiling Space IL's latest prototype nano spaceship with the aim of launching a Israeli robotic spacecraft that will land on the moon and raise funds for scientific education in Israel. (Photo by Ilia Yefimovich/Getty Images)

National Diving School director Jerome Vincent, wearing a Gandolfi space suit, executes training procedures in a swimming pool in Marseille October 22, 2014. The underwater test session develops European expertise in spacewalk simulations under partial gravity for exploring the Moon, asteroids and Mars.The training is organised by Comex, a French company specializing in engineering and deep sea diving operations, in collaboration with the European Space Agency (ESA) and with Apollo XI “Under the sea”. (Photo by Jean-Paul Pelissier/Reuters)

Indian women beat men with stick (Lathi) during celebration of Lathmar Holi in Nandgaon village of Mathura district in Uttar Pradesh, India on February 25, 2018. Holi is observed in India at the end of the winter season on the last full moon of the lunar month. (Photo by Javed Sultan/Anadolu Agency/Getty Images)

Student Rabindra Bharati University celebrates the Holi festival, Color Festival on February 26, 2018 in Kolkata, India. Holi, the popular Hindu spring festival of colours is observed in India at the end of the winter season on the last full moon of the lunar month, and will be celebrated on March 1 this year. (Photo by Debajyoti Chakraborty/NurPhoto via Getty Images)

A SpaceX Falcon Heavy rocket lifts off from historic launch pad 39-A at the Kennedy Space Center in Cape Canaveral, Florida, February 6, 2018. The world' s most powerful rocket, SpaceX' s Falcon Heavy, blasted off Tuesday on its highly anticipated maiden test flight, carrying CEO Elon Musk' s cherry red Tesla roadster to an orbit near Mars. Screams and cheers erupted at Cape Canaveral, Florida as the massive rocket fired its 27 engines and rumbled into the blue sky over the same NASA launchpad that served as a base for the US missions to Moon four decades ago. (Photo by Thom Baur/Reuters)

A masked Burundian protester faces soldiers in front of a burning barricade during an anti-government demonstration against President Pierre Nkurunziza's bid for a third term in the capital Bujumbura, Burundi, 25 May 2015. Street protests continued on 25 May as the United Nations Secretary-General Ban Ki-moon condemned the killing of the leader of the oppsition party Union for Peace and Development (UPD) Zedi Feruzi who opposed Nkurunziza's bid. (Photo by Dai Kurokawa/EPA)

The Borobudur temple seen illuminated during Vesak Day, commonly known as “Buddha's birthday”, at the Borobudur Mahayana Buddhist monument on May 6, 2012 in Magelang, Indonesia. Buddhists in Indonesia celebrate Vesak at the Borobudur temple annually, which makes it the most visited tourist attraction in Indonesia. Vesak is observed during the full moon in May or June and the ceremony centers around three Buddhist temples, whereby pilgrims walk from Mendut to Pawon, ending at Borobudur. The stages of life of Buddhism's founder, Gautama Buddha, which are celebrated at Vesak are his birth, enlightenment to Nirvana, and his passing. (Photo by Ulet Ifansasti/Getty Images)

This undated image provided by World View shows World View capsule and balloon spacecraft that will rise to 100,000 feet above Earth for passengers to see the curvature of the planet and the blackness of space. Space tourism companies are employing designs including winged vehicles, vertical rockets with capsules and high-altitude balloons. While developers envision ultimately taking people to orbiting habitats, the moon or beyond, the immediate future involves short flights into or near the lowest reaches of space without going into orbit. (Photo by World View via AP Photo)