The Clarke Exobelt is the name that Dr Hector Socas-Navarro has given to perhaps the largest structure humans have built. A collection of satellites in earth orbit (geosynchronous) 36,000 km radius. All circling the earth at the same speed in the same direction. The density of this orbit has been increasing since the 1960s but is not yet sufficiently dense for detection from interstellar distances. But in 200 years it may be. In the meantime, this concept works the other way around too. SETI researchers can search for these megastructures or Tecno Signatures to look for extraterrestrial intelligence

The Clarke Exobelt is the name that Dr Hector Socas-Navarro has given to perhaps the largest structure humans have built. A collection of satellites in earth orbit (geosynchronous) 36,000 km radius. All circling the earth at the same speed in the same direction. The density of this orbit has been increasing since the 1960s but is not yet sufficiently dense for detection from interstellar distances. But in 200 years it may be. In the meantime, this concept works the other way around too. SETI researchers can search for these megastructures or Tecno Signatures to look for extraterrestrial intelligence

European Space Agency's Dr Paul McNamara was studying low-frequency gravitational waves just before they were discovered in 2015. Now he is the astronomy and astrophysics coordinator for the European Space Agency. In this interview, recorded in Athens during Cospar2022, he speaks about some of the exciting science missions that ESA will be launching later this decade.

Dr Ralph Lorenz speaks about Dragonfly, a return mission to land on Titan. This mission, for which he is the mission architect, is like no other. It is not really a lander or rover but a quadcopter that will sample different regions near the landing site during its 3.3-year lifetime.

When it comes to the pioneers of rocketry, tradition has it that it was Tsiolkovsky, Goddard and Oberth. in this episode, author Rob Godwin talks about William Leitch from Scotland. He was writing about rocketry from the 1850s

Astronomer Dr Connor Nixon @shamrocketeer speaks about the @nasawebb program to observe solar system objects using the #JWST led by @hbhammel

In 1972, Harrison Schmitt became the first (and so far only), scientist to walk on the surface of the Moon. Since then many scientists have brought their scientific insights to understanding to the solar system and their moons. geologist @sanjeevgupta45 from @imperialcollege talks about Mars

Niklas Hedman, the Acting Director of the @UN Office for the Peaceful Uses of Outer Space (UNOOSA) talks about @UNOOSA ongoing role in facilitating and promoting the peaceful uses of space in Low Earth orbit and beyond.

Sandra Benitez-Herrera talks about the opportunities for teachers and students made available by the European Space Agency 's CESAR (Cooperation through Education in Science and Astronomy Research) program. @esa

A chance meeting with James van Allen led Stamatios Krimigis to build instruments for Mariner 3 and 4. Eventually became a Principle Investigator for the charged particle instrument on voyager which was initially known as Mariner Jupiter Saturn 77 program