Watch Live: Astronaut Scott Kelly Talks About His Year in Space

American astronaut Scott Kelly returned to Earth this week after spending a year in space and will speak about the experience in a NASA news conference on Friday afternoon.

Kelly spent a year on the International Space Station, a mission that aimed to to help scientists understand the effects of prolonged zero-gravity exposure on the human body. Kelly’s twin brother, a retired astronaut, participated in parallel studies on Earth.

Kelly and Russian cosmonaut Mikhail Kornienko landed back on Earth in Kazakhstan on Tuesday after a historic 340 days in space.

Read more: Inside the Gigantic Operation to Meet Astronauts Coming Home

TIME chronicled the year-long mission for a documentary series, A Year in Space, which premiered Wednesday on PBS.

Subscribe to TIME

Get our Space Newsletter. Sign up to receive the week's news in space.

Please enter a valid email address.

* The request timed out and you did not successfully sign up. Please attempt to sign up again.

Sign Up Now

An unexpected error has occurred with your sign up. Please try again later.

Check the box if you do not wish to receive promotional offers via email from TIME.

You can unsubscribe at any time. By signing up you are agreeing to our Terms of Service and Privacy Policy. This site is protected by reCAPTCHA and the Google Privacy Policy and Terms of Service apply.

Thank you!

For your security, we've sent a confirmation email to the address you entered. Click the link to confirm your subscription and begin receiving our newsletters. If you don't get the confirmation within 10 minutes, please check your spam folder.

Write to Katie Reilly at Katie.Reilly@time.com.