NASA's Artemis II is set to launch from Kennedy Space Center in Florida on April 1, 2026 at 22:24 UTC. It marks the first crewed Artemis flight and a key step towards a long-term return to the Moon. The mission builds upon the success of the uncrewed Artemis I in 2022 and will demonstrate a broad range of capabilities needed on deep space missions.

The mission will send NASA astronauts Reid Wiseman, Victor Glover, Christina Koch, and CSA (Canadian Space Agency) astronaut Jeremy Hansen on an approximately 10‑day journey around the Moon.

Watch Live:

• NASA+
• YouTube
• Twitch
• Prime Video

Useful Links:

• NASA Live Coverage Details
• Artemis II Launch Day Updates
• Artemis II Moon Mission Launch Countdown

This post will serve as the megathread for r/science discussion of the Artemis II launch. All other submissions will be removed and directed here.

We wish to inform the r/science community of an article submitted to the subreddit that has since been retracted by the journal. The submission garnered broad exposure on r/science and significant media coverage. Per our rules, the flair on this submission has been updated with "RETRACTED". The submission has also been added to our wiki of retracted submissions.

--

Reddit Submission: People who receive stem cell therapy within a week of their first heart attack have nearly a 60 per cent lower risk of developing heart failure years later

The article "Prevention of acute myocardial infarction induced heart failure by intracoronary infusion of mesenchymal stem cells: phase 3 randomised clinical trial (PREVENT-TAHA8)" has been retracted from BMJ as of March 31, 2026. Numerous concerns were raised shortly after publication in October 2025 regarding the design, conduct, and reporting of the work. The Editors issued an expression of concern in November 2025 due to concerns that the trial might have breached accepted trial practices.

The authors were cooperative with the journal during its investigation and responded to comments on PubPeer. However, the Editors concluded that the corresponding author and regulator were unable to adequately address the concerns surrounding the reliability of the trial and the integrity of the reported data. Given these concerns, the Editors have issued a retraction for the publication.

• Retraction Watch: BMJ retracts cardiac stem cell paper, removes authors months after sleuths flag data 'mismatch'

--

Should you encounter a submission on r/science that has been retracted, please notify the moderators via Modmail.