Here are the most important news items that investors need to start their trading day:

1. Ugly Monday

Stock markets ended last week on a sour note, as all three major U.S. indexes sold off sharply for their worst closes in months after Federal Reserve Chairman Jerome Powell said the central bank would continue fighting inflation with rate increases. This week doesn't look like it'll get off to such a hot start either. Futures were down across the board Monday morning, with no new economic data or major earnings reports expected. Investors are looking forward to the August jobs report, scheduled for Friday, as they weigh just how big a rate hike could be coming from the Fed in September.

2. Shooting for the moon, again

NASA is preparing to return to the moon, in style. While the Artemis I mission won't have a crew or actually land on the moon, it'll mark an important milestone for space travel, nonetheless. It will feature NASA's most powerful rocket, and will place the space agency on track to putting people back on the moon. The Artemis project has faced several delays and has gone several billion dollars over budget, so its first mission is high stakes, to say the least. CNBC's Michael Sheetz breaks it down. The mission was set to launch as early as 8:33 a.m. ET Monday, although it could end up delayed to another date. (Update: NASA postponed the launch.)

3. No more free Covid tests from the government

The federal government will stop sending free Covid tests to Americans this Friday, NBC News reported, citing a senior Biden administration official. "If Congress provides funding, we will expeditiously resume distribution of free tests through covidtests.gov," the person said, according to NBC. "Until then, we believe reserving the remaining tests for distribution later this year is the best course." The development comes as children head back to school and many large employers compel their workers to return to the office. Google employees have said they face numerous notices of Covid infections, and some are calling for changes to the company's vaccine policy.

4. UN inspectors head to Ukraine nuclear plant

A team from the United Nations' International Atomic Energy Agency is headed for the Zaporizhzhia nuclear power plant in Ukraine. The facility, the largest of its kind in Europe, has been in focus amid intense fighting between Ukrainian and Russian forces in the area. The Russians have been shelling the region around the plant, triggering fears of a nuclear meltdown. The inspectors will examine damage to the plant and evaluate whether it's safe and secure. Read more Ukraine war updates here.

5. Serena's last hurrah

Serena Williams is ready to call it a career on the professional tennis court. Earlier this summer, the superstar, who turns 41 next month, said she would leave the sport after the U.S. Open winds up. Williams, arguably the greatest tennis player of all time, is looking for one last Grand Slam title, which would tie her with Margaret Court for the most ever (24). Williams, who has said she would spend more time on her venture capital business in retirement. is set to play Danka Kovinic in the first round at 7 p.m. ET on Monday in Queens, New York.

Some stories you might have missed over the weekend:

• Cash is king for electric vehicle makers as soaring battery prices drive up production costs
• People returning to offices are still buying breakfast even as they cut back on other things
• Chinese tech giants had their worst quarterly growth on record, thanks to Beijing's zero-Covid policy

— CNBC's Jesse Pound, Michael Sheetz, Jennifer Elias and Arjun Khrapal contributed to this report.

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