Saturn's moon Mimas — which looks oddly like the Death Star from "Star Wars" fame — might be harboring an ocean beneath its crust.

Why it matters: Ocean worlds are thought to be some of the best places in the solar system — and beyond — to search for possible alien life.

Before humans can settle off-Earth, scientists need to figure out how — or even whether — people can reproduce in space.

Why it matters: Powerful figures in the space industry like Elon Musk and Jeff Bezos have dreams of a future where millions of people live in space, which would naturally require a self-sustaining population of humans somewhere other than Earth.

NASA's James Webb Space Telescope has officially reached its destination about 1 million miles from Earth, bringing it closer to science operations later this year.

Why it matters: The $10 billion space telescope is designed to change the way scientists understand how the universe formed not long after the Big Bang.

Our Earth and Sun sit almost exactly in the middle of a 1,000 light-year-wide cosmic bubble of plasma, gas and dust propelled by the explosions of surrounding stars, according to a new study.

Why it matters: By studying the bubble from Earth's vantage point, scientists have the chance to observe stars forming and evolving in a process fed by dying and exploding stars that created this bubble.

Twilight images taken by a telescope in California increasingly have streaks from satellites in them, according to a new study examining the effect of SpaceX's Starlink satellites on the night sky.

Why it matters: SpaceX has launched hundreds of internet-beaming satellites to orbit in recent years, stoking fears from some scientists that the small, relatively low-orbiting satellites could make astronomy harder.

NATO will consider an attack against a member country's assets in space as an assault on the alliance, and such actions could lead to a coordinated armed response from all members if necessary, according to NATO's first formal, public space policy released Monday.

Why it matters: The policy reflects the increasing importance of space to more countries. It also normalizes NATO's intentions in space as China, Russia, India and other countries push forward on their science and military ambitions in orbit and beyond.

NASA's next crewed missions to the Moon will need a larger, differently-trained and multi-skilled astronaut corps to deliver on the agency's ambitions.

Why it matters: NASA has plans to fly astronauts to the surface of the Moon in 2025 and ultimately establish a long-term presence there. That goal requires a robust corps with new, specialized training in what it takes to live and work on the Moon — and NASA needs to start planning now.

A team of scientists using archival data has spotted a black hole shredding a star in deep space.

Why it matters: This kind of stellar sleuthing can be used to find more of these types of events and piece together the details of how galaxies evolve through time.

NASA's James Webb Space Telescope is fully deployed in space, and it should be able to perform its science for decades to come.

Why it matters: The longer the JWST can perform its science, the more data it can gather about the evolution of the universe. The $10 billion space telescope is the successor to the Hubble Space Telescope, which has been in space for more than 30 years.

NASA administrator Bill Nelson has appointed Katherine Calvin as the agency's new chief scientist and senior climate adviser.

Why it matters: These are two top science policy positions at NASA.