Live coverage: Space station crew back on Earth

The Atlas 5 rocket that will send NASA’s Perseverance rover toward Mars next month aced a countdown rehearsal Monday at Cape Canaveral, helping ensure the United Launch Alliance-built rocket is ready for liftoff during the rover’s 23-day launch window.

Space missions dispatched into the solar system often have journeys lasting years before reaching a scientific payoff, but NASA’s Parker Solar Probe launched last weekend on a speedy departure from planet Earth is already getting ready to sweep closer to the sun than any spacecraft in history during a flyby later this year.

Peering down at the Earth’s atmosphere from a research window aboard the International Space Station, a new science instrument launching Tuesday will compose unprecedented characterizations of the chemical makeup of shooting stars.