The Artemis II astronauts are on track for a splashdown in the Pacific to close out humanity's first voyage to the moon in more than half a century. The tension in Houston's Mission Control is mounting as the miles melt away between the four returning astronauts and Earth. Their Orion capsule is expected to hit 32 times the speed of sound as it reenters the atmosphere Friday. It's a blistering blur not seen since NASA's Apollo moonshots of the 1960s and 1970s. The recovery ship is already in position, awaiting the crew's arrival, along with military planes and helicopters.

The Artemis II astronauts are tidying up their lunar cruiser for Friday's "fireball" return to Earth. They're also reflecting on their historic journey around the moon, describing it as surreal and profound. The three Americans and one Canadian are now under 150,000 miles from home. Humanity's first lunar explorers in more than a half-century, they set a new distance record during Monday's lunar flyby. Artemis II is aiming for a splashdown in the Pacific off the San Diego coast.

The Artemis II astronauts are chatting it up with their friends aboard the International Space Station. Still aglow from their triumphant lunar flyby, the three Americans and one Canadian put in a call to their station colleagues Tuesday while heading home from the moon. It's the first such moonship-to-spaceship radio linkup ever. "We have been waiting for this like you can't imagine," the commander Reid Wiseman said. NASA's Apollo moonshots had no off-the-planet company back in the 1960s and 1970s. For Artemis II's Christina Koch and the station's Jessica Meir, it was a joyous space reunion despite being 230,000 miles apart. The two teamed up for the world's first all-female spacewalk in 2019.

The Artemis II astronauts have captured Earth's brilliant blue beauty as they zoom ever closer to the moon. NASA released the crew's first downlinked images Friday, 1 1/2 days into the first astronaut moonshot in more than half a century. The first photo taken by commander Reid Wiseman shows a curved slice of Earth in one of the capsule's windows. The second shows the entire globe with the oceans topped by swirling white tendrils of clouds. It even includes a pale green aurora. As of midday Friday, the crew was 100,000 miles from Earth and quickly gaining on the moon.

Spring gets its official start Friday in the Northern Hemisphere with the arrival of the vernal equinox. But what does that mean? The Earth's axis is tilted at an angle as it travels around the sun. On the equinox, the Earth's tilt is neither toward nor away from the sun, so both hemispheres get the same amount of sunlight. This means day and night last about the same amount of time. It also marks the start of a new season. Days will get a little longer every day in the Northern Hemisphere until the solstice in June.

Sunday marks the shortest day of the year in the Northern Hemisphere, signaling the start of astronomical winter. In the Southern Hemisphere, it's the longest day, marking the beginning of summer. The term "solstice" comes from Latin, meaning the sun's "pause" in its annual path. After the winter solstice, the sun begins to climb higher, and days gradually lengthen until late June. Solstices have been celebrated for ages, with monuments like Stonehenge aligning with the sun's paths. The equinox, in contrast, is when both hemispheres receive equal sunlight, leading to nearly equal day and night lengths.

It's almost time to catch summer's double meteor showers. The Southern Delta Aquariid and Alpha Capricornid meteor showers peak in the early morning of July 30. With minimal interference from moonlight, the meteors should appear bright and clear if viewed away from city lights. Each shower is expected to produce up to a dozen visible meteors per hour. The Alpha Capricornids may have tails that linger longer in the night sky. Viewing of each shower lasts through August 12. The next major meteor shower, the Perseids, will peak in mid-August.