Designing Your First Payload: What You Need to Know Before You Fly

So you’ve decided to fly an experiment on a suborbital rocket. Welcome to the fun part.

Whether you’re a researcher testing a hypothesis in microgravity or a hardware team looking to validate a sensor before your first orbital mission, the process of designing a payload for suborbital flight is more straightforward than most people expect. But there are a few things worth getting your head around early, before you start building.

Here’s a practical walkthrough of the key constraints you’ll be designing around on Mini Meggs.

Start with the box

The first thing to nail down is mechanical fit. The usable payload envelope on Mini Meggs is 145mm x 310mm, with a maximum mass of 6kg. Think of it like a very capable carry-on with strict size rules.

Payloads mount to a standard adapter plate using a CubeSat-compatible pattern, which means off-the-shelf hardware often fits without modification. If your centre of mass is off-centre, that’s not automatically a problem. Declare it early and we can compensate during integration.

The hard rules: nothing can protrude outside the defined envelope, and anything with deployables or moving parts needs pre-approval. Keep it clean and contained.

Power: self-contained is simplest

Our strong recommendation for first-time flyers is to design your payload to be self-powered. It’s simpler to integrate, easier to test on the bench, and removes one potential point of failure before flight.

That said, if your experiment genuinely needs an external supply, we provide a 28V regulated interface with up to 2A continuous draw available. All power requirements need to be declared during your payload review, and there’s no charging during flight.

If you’re running batteries, make sure they’re declared in your documentation and compliant with safety requirements. Batteries over 100Wh need extra attention during the review process.

Getting your data back

This is the question almost every first-time flyer asks: how do I get my data?

There are two options. The standard telemetry allocation gives you up to 4kb/s of live downlink during flight, transmitted over a 915MHz LoRa profile. It’s well suited for sensor readings, state flags, and health data. Think IMU values, temperature, pressure. It’s not suited for full-frame images or high-rate raw science data.

If you need more, the Black Box Recorder is your answer. It’s a dedicated onboard logger housed in a titanium enclosure, designed to capture high-fidelity data and survive the full flight including recovery. It’s independent of the vehicle systems and delivers your full dataset after payload retrieval. For biology experiments, high-frequency sensors, or anything requiring continuous internal logging, the Black Box is worth the upgrade.

What your payload is going to experience

This is where a lot of first-time flyers are caught off-guard, so it’s worth being direct about what the flight environment actually looks like.

During ascent, you’ll see up to 6g of acceleration. That’s not extreme by aerospace standards, but it’s enough to knock out fragile structures or loose components if you haven’t designed for it. Build for it from the start.

Above 30km, the payload bay is vented, meaning internal pressure tracks ambient. By the time you’re near apogee, you’re in near-vacuum conditions, around 2 to 3 pascals. If your experiment involves fluids, sealed chambers, or pressure-sensitive materials, this needs to be factored into your design. Pressurised payloads aren’t currently supported.

Temperature-wise, most standard electronics will cope fine within a 10 to 70 degree Celsius range. For sensitive components, passive insulation is usually sufficient.

Recovery is via parachute, which means your payload will experience a shock load at chute deployment and a ground impact on landing. Terrain and conditions at White Cliffs vary. Protect your internals, especially anything fragile or high value.

The timeline matters more than you think

One thing that surprises people is how much lead time the process requires. To fly in a given window, you need to begin the onboarding process at least three months out. The reviews, documentation, integration, and testing all take time. Earlier is always better, especially for first-time flyers.

The process is designed to be straightforward. A discovery call to understand your mission, a feasibility review, booking and deposit, detailed payload review at six weeks out, integration and testing at three weeks, and then you fly.

What’s next

If you’re thinking about flying a payload and want to understand whether your concept is feasible, the best first step is to download our payload guide. The full technical specs, interface details, and integration checklist are all in the Mini Meggs Payload Integration Guide.

You can get it here: https://sunsp.co/payload-guide

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