A large cluster of stars 19,000 light-years from Earth harbors something strange: Within the cluster, a neutron star left over after a supernova explosion orbits a star not too different from our Sun.

The big picture: The Chandra observatory has been observing that star system — known as Terzan 5 CX1 — for more than a decade, and in that time, Terzan 5 CX1 has gone from looking like one type of star system to another and back again.

The last company vying for a $12 million DARPA prize for launching rockets two times from two locations with little notice could stage its first flight as early as this week.

The big picture: DARPA's launch challenge is designed to simulate a real-life scenario that the military may require of its launch providers in the future.

Mars shakes with quakes more often than scientists initially expected, according to a new series of studies using data from NASA's InSight lander published this week.

Why it matters: Mars looks like a cold, dead world, but its geology is complicated. The InSight lander, which has been studying the Red Planet from its surface since 2018, is giving scientists a fuller picture of the rusty world.

Multiple space tourism companies are aiming to send their first customers to the edge of space before the end of this year.

Why it matters: Right now, most revenue in the space industry is tied up in government contracts, but experts say the maturing industry will need tourism to grow into the $1 trillion economy some predict it could be.

NASA mathematician Katherine Johnson, whose calculations helped astronauts reach orbit and eventually land on the Moon, died Monday at 101.

Why it matters: Her work, dramatized in the 2016 film "Hidden Figures," helped to create some of the agency's core mathematical principles behind manned space travel.

Thirty years ago, a probe headed for distant space turned around and took a final photo of Earth.

Context: Known as the "Pale Blue Dot," the image has lived on, and last week NASA released a newly processed version of it that shows our world and everyone on it as a bright pixel nestled in a sunbeam.

A privately funded hunt for intelligent extraterrestrial life has turned up empty so far, but a newly released trove of data could aid in the search.

The big picture: The search for alien life has gone mainstream in recent years, with multiple scientific ventures looking for radio signals that could signify the presence of intelligent civilizations somewhere else out there.

Galactic cosmic rays from outside of the solar system may change the atmosphere of Saturn's moon Titan, according to a new study.

Why it matters: Titan is one of the most intriguing objects in the solar system — with a thick atmosphere and liquid lakes of hydrocarbons — and scientists think it could harbor the ingredients necessary to support life in some form.

SpaceX has penned a deal with the space tourism outfit Space Adventures to launch private citizens to orbit aboard the company's Crew Dragon capsule.

Why it matters: SpaceX is building and testing the Crew Dragon to fly astronauts to the International Space Station, but this announcement shows they're thinking about orbital space tourism as a possible driver of revenue for them in the future.