Should your startup opt for SAFEs or convertible notes on your next funding round? This Houston expert weighs in. Photo via Getty Images

As both a founder and occasional early-stage investor in the Houston ecosystem, I've seen firsthand the opportunities and challenges surrounding seed funding for local startups. This critical first fundraising round sets the trajectory, but navigating the landscape can be tricky, especially for first time founders who may not be familiar with the lingo.

One key dynamic is choosing the right deal structure — SAFEs (Simple Agreement for Future Equity) vs. convertible notes are the most common vehicles early stage startups use to raise capital and are far more founder-friendly than a priced round.

Let's start first with what the have in common:

  • Both allow you to defer setting a valuation for your company until a later (likely priced) round, which is useful in early stages or pre-revenue companies
  • Both are cheaper and faster to execute than a priced round, which cash-strapped early stage founders like
  • Both can have terms like valuation cap, discount, conversion event, and pro rata rights.
  • Both are less attractive to investors seeking immediate equity (especially important if starting the QSBS clock is part of your investors strategy or if the investor is newer to startup investing)
  • Both can create messy cap tables and the potential for a lot of dilution for the founders (and investors) if they are used for multiple raises (especially with different terms)

While as you can see they have similarities, they have some important differences. Let's dig in on these next:

SAFEs:

  • Created by Y Combinator in 2013, the intent was to create a simplified, founder friendly agreement as an alternative to the convertible note
  • Is an agreement for future equity for the investor at a conversion event (priced round or liquidation event) which converts automatically.
  • It's not a debt instrument and does not accrue interest or have a maturity date.
  • Generally have much lower upfront legal costs and faster to execute

Convertible Notes:

  • A debt agreement that converts to equity at a later date (or conversion event like a priced round)
  • Accrues interest (usually 2 to 8 percent) and has a maturity date by which the note must either be repaid or convert to equity. If you reach your maturity date before raising a qualifying round, you can often renegotiate to extend the maturity date or convert the note, though be prepared to agree to higher interest rates, additional warrants, or more favorable conversion terms.
  • More complex and take longer to finalize due to non-standard terms resulting in higher legal and administrative costs

It's worth reiterating that in both cases, raising multiple rounds can lead to headaches in the form of complex cap tables, lots of dilution, and higher legal expenses to determine conversion terms. If your rounds have different terms on discounts and valuation caps (likely) it can cause confusion around equity and cap table structure, and leave you (the founder) not sure how much equity you will have until the conversion occurs.

In my last startup, our legal counsel — one of the big dogs in this space for what it's worth — strongly advised us to only do one SAFE round to prevent this.

Why do some investors tend to prefer convertible notes?

There are a few reasons why some investors, particularly angel investors from developing startup ecosystems (like Houston), prefer convertible notes to SAFEs.

  • Because they are structured as debt, note holders have a higher priority than equity investors in recovering their investment if the company fails or is liquidated. This means they would get paid after other creditors (like loans or credit cards) but before equity investors, increasing the likelihood of getting some of their money back.
  • The interest terms protect investors if the founder takes a long time to raise a priced funding round. As time passes, interest accumulates, increasing the investor's potential return. This usually results in the investor receiving a larger equity stake when the note converts. However, if the investor chooses to call in the note instead, the accrued interest would increase the amount of money owed, similar to a traditional loan
  • More defined conversion triggers (including a maturity date) gives investors more control and transparency on when and how their investment will convert.
  • Can negotiate more favorable terms than the standard SAFE agreement, including having both a valuation cap and a discount (uncommon on a SAFE, which usually only has one or the other), interest rates, and amendment clauses to protect them from term revisions on earlier investors by future investors (called a cram-down), etc.
We'll go over what the various terms in these agreements are and what to look out for in a future article

How to choose:

  • Consider your startup's stage and valuation certainty — really uncertain or super early? Either of these instruments are preferable to a priced round as you can defer the valuation discussion
  • Assess investor preferences in your network — often the deciding factor if you don't have a lot of leverage; most local angels prefer c-notes because they see them as less risky though SAFEs are becoming more common with investors in tech hubs like Silicon Valley
  • Evaluate your timeline and budget for legal costs — as I mentioned, SAFEs are way less expensive to execute (though still be prepared to spend some cash).
  • Align the vehicle with your specific goals and growth trajectory

There's no one-size-fits-all solution, so it's crucial to weigh these factors carefully.

The meanings of these round terms like "seed" are flexible, and the average seed funding amount has increased significantly over the past decade, reaching $3.5 million as of January 2024. This trend underscores the importance of choosing the right funding vehicle and approach.

Looking ahead, I'm bullish on Houston's growing startup ecosystem flourishing further. Expect more capital formation from recycled wins, especially once recently minted unicorns like High Radius, Cart.com, Solugen, and Axiom Space exit and infuse the ecosystem with fresh and hungry angels, new platforms beyond traditional venture models, and evolving founder demographics bringing fresh perspectives.

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Adrianne Stone is the principal product manager at Big Cartel and the founder of Bayou City Startups, a monthly happy hour organizer. This article original ran on LinkedIn.

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Venus Aerospace closes $91 million Series B to scale hypersonic engine

flight funding

Houston-based Venus Aerospace has closed a $91 million Series B round and plans to scale the production of its hypersonic engine.

The round was led by Houston-based Mercury Fund with participation from Lockheed Martin Ventures, MESH, PEAK6, Draper Associates, Starboard Star Venture Capital, Green Sands Equity and other investors, according to a news release.

The investment comes about a year after Venus completed the first U.S. flight test of its high-thrust rotating detonation rocket engine (RDRE). The engine is expected to enable vehicles to travel four to six times the speed of sound from a conventional runway and is about 15 percent more efficient than traditional alternatives, according to the company.

Venus Aerospace says the latest round of funding will allow it to move the RDRE from demonstration to deployment and meet customer requirements for the near-term defense and space industries. The company says that the reusable RDRE is designed with a "common propulsion architecture" that can work for multiple industries and mission types.

“This financing marks an important step in moving Venus from breakthrough demonstration to scaled capability,” Sassie Duggleby, co-founder and CEO, said in the news release. “Our customers need propulsion systems that go farther, can be produced reliably and are built on supply chains they can trust. We are advancing that capability with American engineering and manufacturing talent to strengthen U.S. defense, expand space access and support the future of high-speed flight.”

Venus Aerospace raised a $20 million Series A in 2022, led by Wyoming-based Prime Movers Lab. At the time, the company said it would put the funding toward three main technologies: a next-generation rocket engine, aircraft shape and leading-edge cooling system.

The company also picked up an investment from Lockheed Martin Ventures, the investment arm of aerospace and defense contractor Lockheed Martin, in November 2025—in addition to funding from other investors over the years.

“Since our initial investment, Venus has progressed very quickly in its technology development," Chris Moran, vice president and general manager of Lockheed Martin Ventures, added in the release. "Our reinvestment in Venus recognizes Venus’ accomplishments to date and focus on speed to manufacture, cost management and reduction of supply chain constraints. Venus is working effectively to position its propulsion system for the production scale required by defense programs.”

"Venus is exactly the kind of company Houston capital should be backing," Blair Garrou, co-founder and managing partner at Mercury Fund, added in the release. "It combines multiple frontier technologies, domestic manufacturing and clear commercial and national security relevance. We believe this team is positioned to lead an important new chapter in defense and space, and we are proud to support a company building breakthrough technology here in Texas."

Venus Aerospace and Houston clean tech startup Vaulted Deep were named to the World Economic Forum's Technology Pioneers community earlier this summer. Read more here.

Intuitive Machines lands $148M as part of NASA Moon Base funding

to the moon

Houston-based Intuitive Machines has been awarded $148.3 million to deliver its Nova-C lander to the moon by 2028. The funding is part of $600 million that NASA recently awarded to three companies as part of the agency’s Moon Base Program.

The contracts aim to support sustained human presence and commercial operations on the Moon. Austin-based Firefly Aerospace was awarded $144.2 million by NASA for one mission and Pittsburgh-based Astrobotic netted $297.9 million for two lunar landings. Intuitive Machine's award is the company's sixth task order under NASA's Commercial Lunar Payload Services (CLPS) program.

“We’re building a proving ground for Moon Base operations,” Ryan Stephan, NASA’s Moon Base acting director of cargo landers, said in a news release. “Accelerating our Moon mission ordering cadence and launch opportunities enable us to move quickly to learn, iterate, and improve.”

Under the latest task order, Intuitie Machines will deliver three scientific and operational payloads to the moon, which include a:

  • Linear Energy Transfer Spectrometer (LETS) radiation monitor to gather critical environmental safety data
  • Advanced stereo cameras to analyze surface-plume interactions (SCALPSS)
  • Laser retroreflector array (LRA) for precise cislunar positioning

The funding breakdown includes a $68.6 million base contract and a $79.7 million performance incentive for Intuitive Machines.

The company says the funding will allow it to create a standardized and repeatable "lunar utility pipeline" for delivering cargo to the moon.

"We are shifting the paradigm from custom aerospace engineering to commercial mass production of lunar infrastructure," Steve Altemus, CEO of Intuitive Machines, said in a separate news release. "Our flight-proven Nova-C platform allows us to build, test, and deploy multiple landers in parallel using Industry 4.0-powered manufacturing. This contract directly advances our core mission to provide persistent, reliable, and commercial baseline of transport, connectivity, and operations that allows our customers to stay longer and achieve more on the Moon."

NASA also shared that it is exploring plans to send PROMISE, a rover based on the Mars Perseverance and Curiosity rovers, to the moon and it plans to seek proposals for additional lunar lander missions, technology demonstrations, a communications and navigation satellite network, and new science payloads to support its lunar outpost. NASA is developing its Moon Base near the lunar South Pole. The agency expects it to come to fruition sometime after 2032.

Intuitive Machines had received its last CLPS award for $180.4 million in March 2026. It will be the first mission to utilize the company's larger cargo lunar lander, Nova-D. The company was also recently awarded a $1 million grant from Maryland Gov. Wes Moore to expand its robotics operations in the state.

UT team develops wearable technology for atmospheric water harvesting

In The Air

Engineers at the University of Texas at Austin have developed a prototype jacket that harvests clean drinking water directly from the atmosphere, and it works even in the driest desert conditions.

The research, published in Science Advances, marks the latest milestone in nearly a decade of work by materials scientist and chair professor Guihua Yu and his team at the Cockrell School of Engineering's Walker Department of Mechanical Engineering and Texas Materials Institute. The wearable technology marks a significant leap: instead of a bulky, stationary machine, this jacket does the work.

Photo courtesy of UT Austin

"We have been working on atmospheric water harvesting technology for a number of years," Yu says. "This current version is even more wearable. We're transitioning from conventional, more stationary water harvesting to something truly portable and personal."

Yu's lab first published work on hydrogel-based water harvesting around 2019, and the jacket is the latest evolution of that platform, now called AirGel. Last year, the broader AirGel invention won the top prize in the graduate category of the National Collegiate Inventors Competition.

The jacket is woven with specially engineered hydrogel fibers; ultra-porous materials that attract and absorb moisture from the surrounding air much like a household desiccant. Unlike a desiccant, the material doesn't require intense heat to release that water. The hydrogel is thermally responsive, meaning a modest rise in temperature — even from mild solar heating — is enough to release the water it has captured.

Condenser test in AustinSo, somebody would be wearing the jacket, or perhaps carrying this gel-like textile as a blanket, as it passively absorbs moisture from the air. Then they would detach the textile panels and place them into a small, portable collector unit; essentially a compact heater. The water evaporates out of the textile, condenses inside the collector, and drips out as clean, drinkable water.

"It immediately becomes drinkable because it already goes through the distillation process," Yu explains.

In trials, the jacket produced between 400 and 900 milliliters of water per day depending on humidity, or roughly 14-30 ounces, nearly a quart, depending on the air's humidity. With one kilogram of the textile, the researchers found they could generate approximately 3.7-4 liters of water in arid conditions, and potentially double that in humid ones. So far, the team has tried the jacket out in very dry, semi-dry, and humid areas, and the jacket was able to pull water from each climate.

Lead researcher Chuxin Lei, a postdoctoral researcher on Yu's team and co-author on the paper, says the goal was to rethink who this technology could serve.

Portable bag contents

"Many current [atmospheric water harvesting] systems are still built as rigid or stationary platforms, making them less suitable for people who are moving, working outdoors, or operating in some remote environment. This lead us to ask whether we could build a water harvesting system that could become more like clothing — light, wearable, flexible, and naturally suited for personal use," Lei says.

The potential applications are wide-ranging. Yu's team has previously worked with the Department of Defense on water solutions for soldiers, where water logistics can be dangerous and costly. The technology could also serve hikers, emergency responders, disaster relief workers, and agricultural and field workers. Anyone who needs clean water on the go and far from infrastructure.

The team also sees a potential future where the technology complements large-scale centralized water systems rather than replacing them.

"Our solution cannot be a universal solution for all," Yu acknowledges. "But I think it's an extremely important alternative."

For now, the jacket is still a laboratory prototype, but Yu and Lei are optimistic. With the right industry partnerships, they say, the technology could realistically reach commercial scale within three to five years.

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This article originally appeared on CultureMap.com, written by Natalie Grigson.