Ambassador of Bulgaria to the United States Georgi Panayotov delivers remarks during an Artemis Accords signing ceremony Thursday, Nov. 9, 2023, at the Mary W. Jackson NASA Headquarters building in Washington. Bulgaria is the 32nd country to sign the Artemis Accords, which establish a practical set of principles to guide space exploration cooperation among nations participating in NASA’s Artemis program. Photo Credit: (NASA/Keegan Barber)

U.S. Department of State Deputy Assistant Secretary Sonata Coulter, right, delivers remarks during an Artemis Accords signing ceremony as Minister of Innovation and Growth for Bulgaria Milena Stoycheva looks on Thursday, Nov. 9, 2023, at the Mary W. Jackson NASA Headquarters building in Washington. Bulgaria is the 32nd country to sign the Artemis Accords, which establish a practical set of principles to guide space exploration cooperation among nations participating in NASA’s Artemis program. Photo Credit: (NASA/Keegan Barber)

Minister of Innovation and Growth for Bulgaria Milena Stoycheva delivers remarks during an Artemis Accords signing ceremony Thursday, Nov. 9, 2023, at the Mary W. Jackson NASA Headquarters building in Washington. Bulgaria is the 32nd country to sign the Artemis Accords, which establish a practical set of principles to guide space exploration cooperation among nations participating in NASA’s Artemis program. Photo Credit: (NASA/Keegan Barber)

NASA Administrator Bill Nelson, left, and Minister of Innovation and Growth for Bulgaria, Milena Stoycheva, shake hands following an Artemis Accords signing ceremony, Thursday, Nov. 9, 2023, at the Mary W. Jackson NASA Headquarters building in Washington. Bulgaria is the 32nd country to sign the Artemis Accords, which establish a practical set of principles to guide space exploration cooperation among nations participating in NASA’s Artemis program. Photo Credit: (NASA/Keegan Barber)

Minister of Innovation and Growth for Bulgaria Milena Stoycheva, right, signs the Artemis Accords as NASA Administrator Bill Nelson looks on Thursday, Nov. 9, 2023, at the Mary W. Jackson NASA Headquarters building in Washington. Bulgaria is the 32nd country to sign the Artemis Accords, which establish a practical set of principles to guide space exploration cooperation among nations participating in NASA’s Artemis program. Photo Credit: (NASA/Keegan Barber)

NASA Administrator Bill Nelson, left, and Minister of Innovation and Growth for Bulgaria, Milena Stoycheva, pose for a photo during an Artemis Accords signing ceremony, Thursday, Nov. 9, 2023, at the Mary W. Jackson NASA Headquarters building in Washington. Bulgaria is the 32nd country to sign the Artemis Accords, which establish a practical set of principles to guide space exploration cooperation among nations participating in NASA’s Artemis program. Photo Credit: (NASA/Keegan Barber)

Ambassador of Bulgaria to the United States Georgi Panayotov, left, delivers remarks during an Artemis Accords signing ceremony as NASA Administrator Bill Nelson, second from left, Minister of Innovation and Growth for Bulgaria Milena Stoycheva, second from right, and U.S. Department of State Deputy Assistant Secretary Sonata Coulter, right, look on, Thursday, Nov. 9, 2023, at the Mary W. Jackson NASA Headquarters building in Washington. Bulgaria is the 32nd country to sign the Artemis Accords, which establish a practical set of principles to guide space exploration cooperation among nations participating in NASA’s Artemis program. Photo Credit: (NASA/Keegan Barber)

U.S. Department of State Deputy Assistant Secretary Sonata Coulter, right, delivers remarks during an Artemis Accords signing ceremony as Ambassador of Bulgaria to the United States Georgi Panayotov, left, NASA Administrator Bill Nelson, second from left, Minister of Innovation and Growth for Bulgaria Milena Stoycheva, second from right, look on Thursday, Nov. 9, 2023, at the Mary W. Jackson NASA Headquarters building in Washington. Bulgaria is the 32nd country to sign the Artemis Accords, which establish a practical set of principles to guide space exploration cooperation among nations participating in NASA’s Artemis program. Photo Credit: (NASA/Keegan Barber)

NASA Administrator Bill Nelson, left, delivers remarks during an Artemis Accords signing ceremony as Ambassador of Bulgaria to the United States Georgi Panayotov, second from left, Minister of Innovation and Growth for Bulgaria Milena Stoycheva, second from right, and U.S. Department of State Deputy Assistant Secretary Sonata Coulter, right, look on, Thursday, Nov. 9, 2023, at the Mary W. Jackson NASA Headquarters building in Washington. Bulgaria is the 32nd country to sign the Artemis Accords, which establish a practical set of principles to guide space exploration cooperation among nations participating in NASA’s Artemis program. Photo Credit: (NASA/Keegan Barber)

Minister of Innovation and Growth for Bulgaria Milena Stoycheva, center, delivers remarks during an Artemis Accords signing ceremony as NASA Administrator Bill Nelson, left, and U.S. Department of State Deputy Assistant Secretary Sonata Coulter, right, look on Thursday, Nov. 9, 2023, at the Mary W. Jackson NASA Headquarters building in Washington. Bulgaria is the 32nd country to sign the Artemis Accords, which establish a practical set of principles to guide space exploration cooperation among nations participating in NASA’s Artemis program. Photo Credit: (NASA/Keegan Barber)

Minister of Innovation and Growth for Bulgaria Milena Stoycheva, second from right, delivers remarks during an Artemis Accords signing ceremony as NASA Press Secretary Jackie McGuinness, left, Ambassador of Bulgaria to the United States Georgi Panayotov, second from left, NASA Administrator Bill Nelson, third from left, and U.S. Department of State Deputy Assistant Secretary Sonata Coulter, right, look on Thursday, Nov. 9, 2023, at the Mary W. Jackson NASA Headquarters building in Washington. Bulgaria is the 32nd country to sign the Artemis Accords, which establish a practical set of principles to guide space exploration cooperation among nations participating in NASA’s Artemis program. Photo Credit: (NASA/Keegan Barber)

NASA Administrator Bill Nelson delivers remarks during an Artemis Accords signing ceremony, Thursday, Nov. 9, 2023, at the Mary W. Jackson NASA Headquarters building in Washington. Bulgaria is the 32nd country to sign the Artemis Accords, which establish a practical set of principles to guide space exploration cooperation among nations participating in NASA’s Artemis program. Photo Credit: (NASA/Keegan Barber)

Earth observation taken by the Expedition 39 crew aboard the ISS. Image downlinked in folder: Sofia, Bulgaria and Istanbul, Turkey. Image was released by astronaut on Twitter.

Earth observation taken by the Expedition 39 crew aboard the ISS. Image downlinked in folder: Sofia, Bulgaria and Istanbul, Turkey. Image was released by astronaut on Twitter.

iss067e107088 (June 2, 2022) --- Mount Etna, Europe's tallest active volcano on the coast of Italy's island of Sicily, is pictured billowing with activity as the International Space Station orbited 263 miles above Bulgaria.

ISS036-E-027014 (31 July 2013) --- One of the Expedition 36 crew members aboard the Earth-orbiting International Space Station, as it was passing over Eastern Europe on July 31, 2013, took this night picture looking toward the Mediterranean Sea, which almost blends into the horizon. Also visible are the Aegean Sea, Adriatic Sea and Mediterranean Sea. Parts of the following countries are among those visible as well: Greece, Italy, Sicily, Bulgaria, Serbia, Croatia and Albania. The high oblique 50mm lens shot includes a number of stars in the late July sky. A solar array panel is visible in the darkness on the right side of the frame.

ISS017-E-019550 (14 Oct. 2008) --- The Soyuz TMA-13 spacecraft approaches the International Space Station, carrying NASA astronaut Michael Fincke, Expedition 18 commander; Russian Federal Space Agency cosmonaut Yury Lonchakov, Soyuz commander and flight engineer; and American spaceflight participant Richard Garriott. Fincke and Lonchakov will spend six months on the station, while Garriott will return to Earth on Oct. 23 with two of the Expedition 17 crewmembers currently on the complex. Northeastern Bulgaria, south of the Danube River (along the top) and north of the Balkan Mountains (along bottom), and the western Black Sea (lower right) form the backdrop for the scene.

AS10-34-5026 (18-26 May 1969) --- An Apollo 10 photograph of Earth taken from 100,000 miles away. Visible are many areas of Europe and Africa. Among the features and countries identifiable are Portugal, Spain, Italy, the Mediterranean Sea, Greece, Turkey, Bulgaria, the Black Sea, Libya, Egypt, Saudi Arabia, the Sinai Peninsula, the Nile Delta, Lake Chad, and South Africa. The crew members for Apollo 10 are astronauts Thomas P. Stafford, commander; John W. Young, command module pilot; and Eugene E. Cernan, lunar module pilot. Astronaut Young remained in lunar orbit, in the Command and Service Modules (CSM) "Charlie Brown", while astronauts Stafford and Cernan descended to within nine miles of the lunar surface, in the Lunar Module (LM) "Snoopy".

ISS010-E-08224 (22 November 2004) --- Mount Olympus, Greece is featured in this image photographed by an Expedition 10 crewmember on the International Space Station (ISS). Mount Olympus is the highest peak (2917 meters) in Greece, as well as the mountain chain that runs north into Bulgaria and south, via the Cyclades Islands, into Turkey. In this winter view, Olympus is the only peak with a dusting of snow—perhaps for this reason its name in classical Greek means “the luminous one.” In Greek mythology the peak was inhabited by the Twelve Olympians, the most famous gods of the ancient Greeks. North of Mount Olympus lies Macedonia, the homeland of Alexander the Great. Climbing the mountain is a favorite tourist activity today. The slopes of the peaks of Olympus and its neighboring peaks drop sheer into the Thermaikos Gulf, a northern arm of the Aegean Sea. White cirrus clouds obscure the shoreline near the city of Thessaloniki. This major port is spread along the shores of a small and well protected bay at the north end of the gulf. On the plains inland of the Olympus chain lie a lake, on the Aliakmon River, and the town of Larisa, at the focus point of a series of transport routes.

STS071-741-004 (27 June-7 July 1995) --- Docked already with Russia's Mir Space Station and backdropped against a half globe of Earth featuring the Crimean Peninsula, the space shuttle Atlantis is partially visible through a window on the Kvant 2 Module. A 70mm camera, carried into space by the STS-71 crew aboard the space shuttle Atlantis, was used to expose the image. The crew cabin and forward cargo bay of Atlantis are most prominent. Below center can be seen the Androgynous Peripheral Docking System (APDS) and the Kristall Module on Mir. The APDS is connected to a port in a tunnel leading to the Spacelab Science Module in Atlantis' cargo bay. The linkup enabled the seven STS-71 crew members to visit Mir and it allowed the three Mir-18 crew members, in space since March of this year, access to Spacelab. That module was quite busy with tests and data collection involving the three, Mir-18 crew, until Atlantis brought them home on July 7, 1995. The Black Sea lies directly beneath Atlantis, with Ukraine's diamond-shaped Crimean Peninsula immediately to the right of the cockpit. The wide lower course of the Dnepr River can be seen entering the Black Sea at far right. The coast of Romania and Bulgaria lies at a point where the cloud begins at top right. The peninsula of Asia Minor lies across the left of the view, mostly under cloud cover. The Mediterranean Sea is the cloud-free, blue mass beyond. Still further, at about 1,300 miles distance, the north edge of Africa is stretched out as a line across the horizon with its characteristic sandy color. The nose of Atlantis points southwest toward the only outlet of the Black Sea known as the Bosporus.