Tonight on PBS

PBS News Weekend, why this summer's extreme heat is contributing to the nationwide blood shortage.

Then amid the summer surge of COVID cases,

why vaccines will soon be harder to get for uninsured Americans.

And the future of debt relief for black farmers after decades of discrimination.

The very federal arm that was supposed to be lending a hand up for black farmers

was denied us the opportunity to farm in this country the way that

white farmers did. Good evening. I'm John Yang. When two astronauts were launched into space in June, they were supposed to be home in time for the 4th of July.

But today, NASA said they'll be in space for the holidays and into the new year.

NASA officials decided that questions about the propulsion system make it too risky

for the astronauts to return to Earth in the Boeing-built spacecraft that took them to the

International Space Station.

Now the plan is for Sonny Williams and Butch Wilmore

to return on a SpaceX vehicle in February.

Officials say the veteran astronauts are prepared for the lengthy delay,

but it'll be a hardship for

their families. When they launch they know that there are circumstances where

they can be on board for up to a year. I know this is a huge impact to their families and it means a lot.

Their families are the pillars that keep them strong. They're the pillars that we at NASA depend on for the workforce to keep us going.

Despite the series of problems with the Boeing Starliner capsule, NASA Administrator Bill

Nelson says it will carry astronauts again

in future missions. Ukrainian Independence Day brought freedom for 115

...