Tom Wallace-Smith never planned on becoming a deep tech founder. He started out in nuclear engineering, working on the technology that powers Britain’s submarines, then took a left turn into startups via a Zoom call and a wild idea.

Today, as co-founder and CTO of Astral Systems, Tom is leading a team building compact fusion reactors: not to power the grid, but to tackle one of the most stubborn bottlenecks in cancer care: medical isotope shortages.

Tom built Astral with a global team he didn’t meet in person for months, set out to generate revenue before chasing big VC rounds, and spent most of his twenties learning how to defend his vision against critics, investors, and his own doubts. Along the way, he’s had to grow from physicist to operator: hiring, firing, and figuring out how to build a mission-driven culture while scaling fast.

In this episode, Tom opens up about what it really takes to build in deep tech, why commercial traction matters even in the hardest science, and the systems he’s put in place to protect his team and his own sanity.

🔗 Find Tom on LinkedIn

Takeaways from Tom’s episode

1️⃣ Mission beats hype

The most resilient founders stay anchored to a genuine mission. For Tom, solving real-world problems, like cancer treatment shortages, matters more than chasing headlines or “moonshots”.

2️⃣ Commercial traction isn’t optional

In deep tech, revenue isn’t a side quest. Astral focused on getting paying customers early, proving that real business models beat endless fundraising sprints.

3️⃣ Remote teams can build big things

Tom co-founded Astral before meeting his partner in person. Systems, trust, and relentless alignment turned a fully remote team into a commercial deep tech operation.

4️⃣ Assertiveness is a founder’s muscle

Leading a technical team means learning to defend your decisions and hold the line, especially when you’re younger or less experienced than your peers.

5️⃣ Protect your bandwidth

Scaling quickly means setting up reviews, routines, and boundaries to safeguard your own mental health and keep the team running at its best. Tom uses note-taking, journaling, and meditation to stay focused and avoid burnout.

📚 Tom’s book recommendations

Venture Deals by Brad Feld and Jason Mendelson – The go-to handbook for understanding startup fundraising, term sheets, and the language of venture capital. Tom suggests reading it before talking to any investor, angel or otherwise.

Out of Your Mind (lecture series) by Alan Watts – Tom credits these talks for helping him reset, gain perspective, and find mental clarity. He revisits them every few years, always picking up something new.

The Lectures of Richard Feynman – Tom finds Feynman’s lectures a masterclass in making complex topics engaging and accessible, a mindset he channels in both science and leadership.

In this episode we cover:

00:00 Introduction to Tom Wallace-Smith

02:23 Building a deep tech startup from scratch

09:50 The idea behind Astral and remote collaboration

12:31 Co-founder dynamics, trust, and decision-making

16:23 Fusion technology and isotope production explained

18:04 The nuclear medicine shortage problem

20:47 Real-world applications of fusion technology

23:55 The future of isotope production and research

26:25 Long-term vision: disrupting a legacy industry

30:19 Operating in stealth mode and raising capital

36:17 Winning contracts and early commercial traction

42:32 How to pitch investors as a technical founder

48:03 Path to revenue and reaching breakeven

53:48 Hiring in deep tech and scaling a team

59:05 Why fresh perspectives beat experience

01:02:34 Remote vs hybrid teams: what actually works

01:04:17 Learning assertiveness as a young founder

01:07:02 The sacrifices behind startup life

01:12:08 Why founders need hobbies outside work

01:14:13 Journaling and managing mental health

01:17:55 Meditation, focus, and performance

01:21:23 Books every entrepreneur should read

01:23:37 Advice for first-time founders

Get full access to Millennial Masters at millennialmasters.net/subscribe