Main Engine Cut Off

Artemis II is underway with a spectacular first day.

There was a lot of news in NASA’s Ignition event last week, and I break down what actually matters: not whether Jared Isaacman’s timelines are realistic, but how this new roadmap strips away architectural dependencies and forces the real bottlenecks into the open. I talk through Gateway’s cancellation, the possible path away from SLS and ICPS, what this means for lunar landers and international partners, and why NASA’s new philosophy feels so different from the past.

Tom Mueller, Founder and CEO of Impulse Space, joins me to catch up on the company’s progress and plans—3 Mira missions flown, Helios soon to fly, $525M raised, new defense contracts, a lunar lander concept, and a new Colorado facility.

NASA Administrator Jared Isaacman announced a sweeping roadmap change to the Artemis program this morning—seemingly cancelling the EUS, Gateway, and all SLS upgrades, and instead pursuing the once-and-future annual launch cadence of SLS.

Loren Grush, of Bloomberg, joins me to talk about SpaceX’s acquisition of xAI, its preparation for a potential IPO, Blue Origin’s cancellation of New Shepard and their recent momentum, and the delay to Artemis II following its first wet dress rehearsal.

Artemis II is on the pad, and I can’t stop thinking about it. So I guess listen to me think in the open? Also, a ton of Blue Origin news—the next flight of New Glenn will feature a flown booster, they’ve announced constellation plans under the name TeraWave, and Tory Bruno has left ULA to join the team at Blue.

Casey Dreier of The Planetary Society joins me to talk about the NASA FY2026 budget, the early days of the Administrator Isaacman era, and how we feel going into Artemis II.

A holiday special! Enjoy this week’s episode of Headlines free. It’s an absolute monster episode—way longer than usual Headlines episodes, I promise—but it’s a great example of what you get when you support the show over at mainenginecutoff.com/support.

Yesterday, I had the chance to visit the Pentagon and sit down with General Chance Saltzman, Chief of Space Operations—the head of the United States Space Force. We talk about the service 6 years into its existence, the state of acquisitions, the threats and space environment today, and what the future may hold for the Space Force when it comes to human spaceflight.

Stephen Clark of Ars Technica joins me to talk about a ton of stories in the news—Jared Isaacman was back in front of Congress, a few Starliner flights have been cut from the ISS manifest, Starship received environmental approval to proceed at SLC-37, Zhuque-3 almost stuck its first landing attempt, the Soyuz launch pad fell apart at Baikonur, and the Space Force has a new mission naming scheme.