TL;DR: SBIR Phase II funds the real research and development behind a prototype, building on Phase I results, and SBIR.gov says awards may last up to two years. For space startups, the Phase II that matters most is one tied to a committed government customer and end user and a clear transition path, because Phase III is funded from non-SBIR sources.

Key takeaways

• Phase I tests feasibility; Phase II performs the R&D and builds the prototype.
• The Department of the Air Force offers Direct to Phase II for companies with a mature solution and a committed customer.
• Plan the transition to Phase III, contracts or commercial sales from day one.
• Use official program pages for current amounts and deadlines; they change.

What is SBIR Phase II?

According to the SBIR.gov program basics tutorial, Phase I is the concept phase and lasts six to twelve months. Phase II awards may last up to two years and expand on Phase I results, and this is when the R&D work is performed. Phase III is when the innovation moves into the marketplace, and no SBIR funds support it.

If you have not won Phase I yet, start with our SBIR Phase 1 guide.

How does Phase II work for Space Force and Air Force topics?

Many space startups pursue SBIR through AFWERX and SpaceWERX, the Department of the Air Force innovation arms. Our SpaceWERX SBIR guide covers the Space Force program end to end. The AFWERX Get Funded page says:

• Phase II is prototype development, supporting the development and refinement of a prototype with a Department of the Air Force technical point of contact and end user.
• Phase I companies that show scientific and technical merit and commercial potential may compete for Phase II.
• Direct to Phase II (D2P2) is open to companies with a mature solution, an identified DAF customer and end user, and a signed Customer Memorandum.
• Phase II period of performance is up to 24 months, with milestone deliverables and collaboration with the customer and end user to advance transition.

Check the page and current solicitation for award amounts, which change. Other agencies, including NASA and NSF, run their own Phase II processes, so read each one's instructions.

How do you prepare a strong Phase II proposal?

1. Build on Phase I evidence. Show what you proved and what remains.
2. Name the customer and end user. Explain who will use the result and what problem it solves for them.
3. Write a milestone plan with clear, testable deliverables.
4. Show the transition path: which program, contract or commercial market comes next.
5. Show commercial potential, such as dual-use markets, letters of support and customer conversations. Our dual-use positioning guide shows how.
6. Prepare the team and compliance basics, such as registrations, accounting and security, before you need them.

Customer validation helps every step. See our customer validation guide.

What comes after SBIR Phase II?

Phase II is not the finish line. On its Get Funded page, AFWERX lists sequential opportunities after Phase II:

• STRATFI and TACFI, which help companies with a current or recent Phase II bridge from prototype to operational capability with matched funding.
• Strategic Breakthrough, which accelerates proven SBIR/STTR technologies from successful Phase II to operational use, with a required funding match.
• Phase III, which transitions technology to operational use or the commercial market using non-SBIR/STTR funding.

Other routes include prime partnerships and other contract vehicles, which our guide to government contracts for space companies maps out. For prototype agreements outside SBIR, see our guide to other transaction authority for space startups. See selling to prime contractors and how to sell to Space Force.

How should you build a transition plan?

A transition plan answers: who pays after Phase II?

• Identify the program office or buyer that would fund deployment.
• Map their budget and acquisition timeline.
• Line up the end user who will advocate for your technology.
• Plan matching funds if you target programs that require them, including private investment.
• Develop commercial customers in parallel, so you are not dependent on one buyer.

Our space startup funding guide covers how private capital fits alongside awards, and our guide to non-dilutive funding for space startups covers the wider set of equity-free options.

What mistakes stall SBIR Phase II?

• Treating Phase II as the business instead of a step toward customers.
• A vague end user or no real customer engagement.
• Missing milestones or poor reporting.
• No transition plan until the award is nearly over.
• Overlooking compliance such as cybersecurity and export control.

Want to compare notes with other founders working through SBIR? Join Space Entrepreneurs, our free Skool community. For the marketing side of winning and announcing awards, see the space marketing guide.

Frequently asked questions

What is SBIR Phase 2?

The SBIR phase that funds research and development and prototype work, building on Phase I. SBIR.gov says Phase II awards may last up to two years.

Can you skip Phase I and apply directly to Phase II?

Sometimes. The Department of the Air Force offers Direct to Phase II for companies with a mature solution, an identified customer and end user, and a signed Customer Memorandum. Other agencies have their own rules.

How long does SBIR Phase II last?

SBIR.gov says up to two years. AFWERX lists a period of performance of up to 24 months for its Phase II.

What happens after SBIR Phase II?

Phase III, which commercializes the technology using non-SBIR funds, or follow-on programs such as STRATFI, TACFI and Strategic Breakthrough for eligible Air Force and Space Force projects.

How do you improve your chances of winning Phase II?

Build on strong Phase I results, name a committed customer and end user, write a clear milestone plan and show a credible transition and commercial path.

Want to work through this with other space founders?

Join Space Entrepreneurs, free. Space Entrepreneurs is the free Skool community I host for founders who are starting, marketing and growing space companies. Bring your questions, share what you are working on and learn from people building in the same industry.

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