Former Florida senator Bill Nelson was sworn in Monday as head of NASA, hailing a "new day" for space exploration as the United States seeks to return to the Moon.

With his hand on a Bible, Nelson took the oath of office from Vice President Kamala Harris as he officially took up the role of NASA administrator.

"It's a new day in space," he said, after bringing a Moon rock to the event.

Nelson, 78, who traveled into space in 1986, takes over the agency with the United States hoping to put astronauts back on the Moon by 2024.

Humans last set foot on the Moon in 1972 during the Apollo program.

Under the Artemis program, NASA wants to establish a sustainable presence, complete with a lunar space station, to test new technologies that would pave the way for a crewed mission to Mars.

Last weekend, China celebrated its sixth "National Space Day" in Nanjing, an event that highlights advances China has made in space. Similar to Space Day that is held each year on the first Thursday in May (this year, it will be held on May 7th), the goal is to foster interest in space exploration and the STEMS so as to inspire the next generation of astronauts and aerospace engineers.

This year, the festivities focused on the Chang'e-5 mission (which showcased some of the lunar samples it brought back), and the name of China's first Mars rover (Zhurong) – which will be landing on the Red Planet later this month. But another interesting snippet was a video presented by one of China's main rocket manufacturers that showed demonstrated that they are working on a rocket similar to the Starship.

The video, titled "One Hour Global Arrival in the Space Transportation System," was presented by the China Academy of Launch Vehicle Technology (CALT) – one of the country's main state-owned rocket manufacturers.

By Earth standards, the surface of Mars is the picture of desolation. It's not only irradiated and cold enough to make Antarctica look balmy, but it's also one-thousands times drier than the driest places on Earth. However, beneath the super-arid surface of the Red Planet, there are abundant supplies of water ice that could someday be accessible to human explorers (and even settlers).

This is especially the case in the mid-latitude region known as Arcadia Planitia, a smooth plain located in Martian northern lowlands. According to new research conducted with support from NASA's Jet Propulsion Laboratory (JPL), the region shows signs of glaciers and glacier activity. These findings could prove very useful for the future human landings and exploration of Mars, not to mention potential settlement.

The study, which recently appeared in the scientific journal Icarus, was led by Shannon Hibbard—a Ph.D. candidate in geology and planetary science at the University of Western Ontario (UWO). She was joined by Dr. Gordon R. Osinski of UWO's Institute for Earth and Space Exploration (IESE), and Etienne Godin, a data scientist at the Center for Northern Studies at Laval University; and Nathan Williams and Matthew Golombek of NASA JPL.

An icy satellite of Saturn, Enceladus, has been a subject of increasing interest in recent years since Cassini captured jets of water and other material being ejected out of the south pole of the moon. One particularly tantalizing hypothesis supported by the sample composition is that there might be life in the oceans under the ice shells of Enceladus. To evaluate Enceladus' habitability and to figure out the best way to probe this icy moon, scientists need to better understand the chemical composition and dynamics of Enceladus' ocean.

Specifically, an appropriate salinity could be important for habitability. Like the porridge of the Three Bears, the salt level of the water must be just right for life to thrive. Too high a salinity could be threatening to life, and too low a salinity may indicate a weak water-rock reaction, limiting the amount of energy available to life.

In an alternate reality playing out at this year's international Planetary Defense Conference, a fictional asteroid crashes over Europe, 'destroying' a region about 100 km wide near the Czech Republic and German border. The scenario was imagined, but the people who took part are very real, and the lessons learnt will shape our ability to respond to dangerous asteroids for years to come.