# Rockets devote most of their mass to propellant

Markdown copy of https://realalpha.app/s/rockets-devote-most-of-their-mass-to-propellant/ on Real Alpha, the best minutes from long interviews with the people building AI. Cite and link the page, not this copy.

- Speaker: [Eric Schmidt](https://realalpha.app/people/eric-schmidt/) · Eric Schmidt is a former Google executive chairman and CEO. · Scaled Google as CEO through 2011, now runs rocket maker Relativity Space and co-founded Schmidt Sciences.
- Host: [Chamath Palihapitiya](https://realalpha.app/people/chamath-palihapitiya/) · Founder & CEO, Social Capital · Led Facebook's growth team; his firm backed Slack and AI chipmaker Groq.
- Host: [Jason Calacanis](https://realalpha.app/people/jason-calacanis/) · Founder & CEO, LAUNCH · Early Uber angel; sold Weblogs Inc. to AOL; hosts This Week in Startups.
- Host: [David Sacks](https://realalpha.app/people/david-sacks/) · Co-founder & partner, Craft Ventures · PayPal's first COO, founded Yammer; White House AI & crypto czar 2025–26.
- Host: [David Friedberg](https://realalpha.app/people/david-friedberg/) · CEO, Ohalo · Founded The Climate Corporation, sold to Monsanto for about $1.1B in 2013.
- Show: All-In
- Episode: [Eric Schmidt on AI, the Battle with China, and the Future of America](https://realalpha.app/v/EkuVqdj8O6E/), Sep 24, 2025
- Moment: 8:10 to 10:12 of the episode (2 min), playing on https://realalpha.app/s/rockets-devote-most-of-their-mass-to-propellant/; the episode from there: https://realalpha.app/v/EkuVqdj8O6E/?t=490

## Quote

> “a rough number is that 2% of the weight of the rocket is the payload, 18% is roughly the rocket, and **80% is the propellant**.”
> — [Eric Schmidt](https://realalpha.app/people/eric-schmidt/) at [9:23](https://realalpha.app/v/EkuVqdj8O6E/?t=563) · All-In

## Takeaways

1. Rockets remain difficult engineering projects, unlike mature jet engines.
2. About 80% of a rocket’s mass is propellant; payload is about 2%.
3. Relativity targets low Earth orbit, and Schmidt says its order book is full.

## About this segment

Eric Schmidt explains why Relativity Space appealed to him and how rocket mass is divided among payload, vehicle and propellant. The figures show why rocket design leaves little room for easy gains.

From “Eric Schmidt on AI, the Battle with China, and the Future of America”, Sep 24, 2025. [Watch the full episode](https://realalpha.app/v/EkuVqdj8O6E/)

## Transcript

Transcribed by machine (Whisper) from the episode’s audio, so a word may be off here and there.

[8:15](https://realalpha.app/v/EkuVqdj8O6E/?t=495) I think you were the first investor or the earliest investor in it. I was. I'm sorry. It's okay. You lost some money in the first place. I did. What happened? Did you get crammed down? No, no, no. All of us did. All of us. I mean, look, I've been very happily you know, an investor in SpaceX and Swarm and Starlink. Relativity was... By the way, Swarm is a big deal, created Starlink. So thank you. Yeah, Swarm has been a really great success for them, and I think for the world. But what I was going to ask you is, walk us through the evolution of the space market. Why you decided, of all the companies, you have the capital base to kind of put your money anywhere. Why did you pick that?

[8:53](https://realalpha.app/v/EkuVqdj8O6E/?t=533) Why did you pick that business? Why now? Rockets are really cool and they're really hard. I had, as you know, I'm a pilot and I know lots about jets and I had assumed that rockets were as mature as jet engines. They're not. It is an art and a science. These things are very hard to do. The amounts of power, in our case, the rocket is four million pounds of thrust. You have to hold the thing down to test it and you can't even hold it with metal things. You have to have other things to hold it down as well. There's so much force. Otherwise, it will take off. Another interesting thing about rockets is that a rough number is that 2% of the weight of the rocket is the payload, 18% is roughly the rocket, and 80% is the propellant. And my reaction as a new person is, you're telling me you can't do any better?

[9:40](https://realalpha.app/v/EkuVqdj8O6E/?t=580) And the physicists say, after 60 years of physics, that's the best we can do to get out of the gravitation of the Earth. And so I think rockets are interesting and they're challenging. There's always an opportunity for competition. In relativity spaces area, it's essentially a LEO competitor. So low earth orbit, satellites, that sort of thing. The order book is full. We just have to launch the rocket. And this entry into space happened, and I'm not sure how well known