Rapid prototyping helps create aircraft to study atmosphere

Scientists at Southampton University have used rapid prototyping to create an aircraft that will be used to study the Earth’s atmosphere.

The unmanned platform is part of the ASTRA (Atmospheric Science Through Robotic Aircraft) project that aims to demonstrate how a low-cost, custom-built high-altitude platform could be developed and manufactured over a period of a few days.

Dr András Sóbester, project leader from Southampton University, told The Engineer: ‘If there is a phenomenon that happens suddenly and you want to deploy some kind of instrument to measure it then our device is ideal.’ Examples of such phenomena include volcano eruptions and nuclear fall-out.

The balloon-borne platform, dubbed ASTRA Atom, has been built to carry a payload containing atmospheric monitoring equipment into the upper atmosphere. The latex weather balloon, which will stretch from 1.5m in diameter to 5m as it ascends, will carry the Atom to heights of 30km.

The current solution to monitoring atmospheric parameters includes attaching radiosondes to weather balloons, which can contain an array of sensing equipment.

‘The radiosonde has the advantage of being simple to use and deploy but it has a number of drawbacks,’ said Sóbester. ’You can only gather as much data as your bandwidth allows you to transmit back to the ground.’ 

Tracking possibilities

The Atom has been designed so that it can be found after its 5–7-hour flight, giving scientists access to the wealth of data it has accumulated and stored during its flight. In order to find the Atom, the team is trialling two possible tracking strategies.

The first involves putting a mobile phone SIM card into the Atom.

Dr Steven Johnston, a collaborator on the project from Southampton University’s Microsoft Institute of High Performance Computing, said: ‘Although you lose connectivity while it is at altitude… the idea is that when it lands it will reconnect and give you information on the landing location.’

Alternatively, radioteletype technology could be used, as Johnston explained: ‘It has a low bandwidth so you don’t get much data back. However, if you announce the frequency, then the device’s position can be tracked by amateur radio operators around the UK and Europe.’ In addition, they may also upload any data they receive onto the internet for others to see.

The entire structure of the 700g Atom was printed on the university’s 3D printer, which fabricates plastic objects, building them up layer by layer. Furthermore, the onboard data-logging equipment has been built using Microsoft’s rapid electronic prototyping toolkit, .NET Gadgeteer.

Johnston said: ‘.NET Gadgeteer basically lets you choose which components you want and you can have a prototype up and running in hours.

‘The other thing is that it’s open software so there is no commercial licensing, which is paramount for us as it allows us to integrate additional sensors into our current electronics,’ he explained. 

Foam into ’orbits’

The Atom is protected by two foam ‘orbits’, which were manufactured using a computer-controlled hot wire cutter at the university’s Engineering Design and Manufacturing Centre. They are designed to break on landing and absorb the energy of the impact.

The Atom was due to be launched on 7 December at the Imperial War Museum, Duxford, but could not take off due to strong surface winds. The team hopes to launch it at the start of next year, stressing that it is not aimed to be a direct replacement of all radiosondes in operation.

In addition to the Atom, the scientists are working on balloon-based gliders, which can gather more data than a radiosonde and return to the launch spot.