The grand finale of the Low Orbit Helium Assisted Navigator (LOHAN) saga is approaching, and is now so tantalisingly close you could almost reach out and stick a match to it.

It's been a long, winding road, to be sure, but we still have a few things to wrap before we can finally see what happens when you stick a rocket motor in a 3D-printed spaceplane and blast it into the stratosphere.

On Saturday 5 April, a British contingent of the LOHAN team - comprising myself, Dave Akerman, Rob Eastwood, Paul Shackleton and Anthony Stirk - will assemble at an unspecified location somewhere in the west of England and dispatch two balloon missions heavenwards.

The first - dubbed "Punch" - will carry a Cesaroni rocket motor to 20,000m to determine once and for all if our custom igniter will indeed persuade LOHAN to breathe fire at altitude.

LOHAN regulars know this has been one of the most challenging aspects of the project. Tests began back in July 2012, when a first outing for the Rocketry Experimental High Altitude Barosimulator (REHAB) hypobaric chamber...

...rather irritatingly ending in forlorn fizzling as the off-the-shelf igniters failed to deliver at a pressure equivalent to an altitude of around 23,300m. The reason, we suspected, was due to lack of heat transfer from igniter to charge in a oxygen-light atmosphere, so evidently more fire was in order.

Enter reader Rob Eastwood, Head Firer for Flashpoint Fireworks, who brewed up a more incendiary custom igniter:

While this magnificent assemblage did indeed get a motor to go bang in REHAB...

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...we hadn't yet tested the full effects of altitude+cold.

Fast-forward to July 2013, when a high-altitude test of the igniter under the control of the Special Project Electronic Altitude Release System (SPEARS) board revealed that the PIC component, while having previously demonstrated no objection to low pressure, didn't much like the chill.

Here's a post-flight snap, showing how the PIC began to burn, then gave up the ghost:

So, it was back to the drawing board and a new igniter of classified composition which went off with a satisfying pop at 20,000m:

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Cue happy faces for (from L-R) Claire Edwards, Paul Shackleton, Dave Akerman and Rob Eastwood...

...albeit tempered by the fact that we hadn't been able to deploy a loaded rocket motor due to the risk of setting fire to the sun-scorched Spanish countryside and spending some quality time in jail.

Now, finally, we'll send up the igniter plus a motor, and that will (we sincerely hope) be an end to the matter. Since the last flight, the ever enthusiastic Paul and Rob have been eyeing an even more awesome fire-breathing device, the exact composition of which must remain under wraps for now but will be revealed in due course.

Judy: Let's just test this lovely motor toaster, shall we, children?

The second 5 April flight – codenamed "Judy" – will carry the Vulture 2's full-fat Cesaroni 54mm 3G case wrapped in its space-grade Polyimide Thermofoil flexible heater...

...and a heatshrink overcoat, and ultimately connected to a LiPo and thermostat rig:

There's more on this set-up right here, but suffice it to say, the thermostat is on hand to prevent possible heater meltdown in the absence of air at altitude.

Quite honestly, we have no idea what will happen, so a quick jaunt heavenwards is the best way to find out.

As well as the two main tests, Punch and Judy will help us check out the performance of a few of our mission cameras which haven't yet enjoyed a lovely day out at -50°C.

As ever, the balloon launches and pursuit will be streamed live on the interwebs, while radio hams can lend a helping hand by tuning into mission trackers. We'll provide full details as the event gets closer. ®

Bootnote

Yes, yes, all of that's absolutely fantastic, we hear you cry, but why "Punch" and "Judy"? Well, the missions are named in honour of two of my mutts, seen here on left and right with their sister Richard in the centre.

That's right, when I got this trio as small puppies, the desire to name them Punch, Richard and Judy was overwhelming, despite protests from the kids that Richard is a actually a girl. "I don't care, it's too bloody funny," was my response.

And so it was, until I had to attempt to explain the gag to Spanish locals, who tried not very hard to listen patiently to tales of murderous puppets and their wives, British TV personalities, and how their names could be effortlessly intertwined to great comic effect. ®

More from the lovely LOHAN:

• You can find full LOHAN coverage right here.
• If you're new to LOHAN, seek out our mission summary for enlightenment.
• There are photos our our magnificent Vulture 2 spaceplane here, and detailed structural plans here.
• For your further viewing pleasure, we have all our photographic material stored on Flickr.
• Our LOHAN and Paper Aircraft Released Into Space (PARIS) videos live on YouTube.
• We sometimes indulge in light consensual tweeting, as you can see here.