LOHAN's flying truss: One orb or two?

Readers shoot down twin-balloon plan

The roll-out yesterday of our Low Orbit Helium Assisted Navigator (LOHAN) fantastical flying truss prompted a flurry of comments from readers unimpressed with our twin-globe proposal.

To recap, our cunning plan for the Vulture 2 spaceplane launch platform involves a triangular truss constructed from carbon fibre tubes and carried aloft by two helium-filled meteorological balloons.

We've already put together a balsa wood model of the structure (seen below with apprentice boffin Katarina), ahead of a planned flight test as soon as we can get our hands on some helium.

However, many of you expressed serious misgivings about the plausibility of using two balloons. The main problem, as you pointed out, is how to ensure that the launch platform stays horizontal – something which requires absolutely equal lift at both ends.

Furthermore, there's a potential problem with high winds at altitude, which could result in tangled balloon lines.

So, here's how we could rig the truss under a single balloon:

It's a nice solution, but we still have the problem of the Vulture 2 launch trajectory, which needs to be as vertical as possible without any risk of the aircraft hitting the balloon.

These mighty globes expand to gargantuan dimensions at altitude, so unless we use an improbably long tether line to increase the distance between truss and balloon, there's no way we can launch at anything approaching vertical.

For our forthcoming fantastical flying truss test, we'll try both single and twin balloon configurations, and see if a long tether line is a practical possibility. Watch this space... ®

Bootnote

There's one serious objection to scrapping the twin-balloon proposal: we don't get to write headlines such as "Reg team grapples LOHAN's mighty orbs", and so forth.

Further LOHAN resources:

• New to LOHAN? Try this mission summary for enlightenment.
• You can find full LOHAN coverage right here.
• All the LOHAN and Paper Aircraft Released Into Space (PARIS) vids live on YouTube.
• For our SPB photo archive, proceed directly to Flickr.
• We sometimes indulge in light tweeting, as you can see here.