For the past few days we have all been busy testing the metal detection equipment, trouble shooting some issues with the system, and getting all the science equipment packed up and ready to go to the field.
There is a lot of gear needed for the metal detection part of the project — a single detector set up includes:
a skidoo mounted with a display box to signal when the metal detector has a response (see picture below)
a pulling rig
two solar panels coupled to two large batteries powering the communication electronic control box (all mounted on a bright blue sledge)
a boom rig
snow bashers, to flatten a path
five metal detector panels with embedded coils and their control system boxes
All of this is lashed together with various ropes so that it works as a single system, and includes many metres of electrical cables and network cables (in the photo above you can see what a right old mess this is before Romain neatly bundled them together to to help the rebuild when we’re in the field). We have assembled the two separate panel array systems in the cargo yard at Rothera to check that the mechanical setup is complete before we head to the field (i.e. do we have all the right screws and bolts and are not missing anything vital…).
For the past few days our resident electronic engineer Wouter has also been working hard to iron out a few issues with the electronic systems — a lot of head scratching to get to the root of the glitches, but thanks to his hard work (and thanks to Liam and John as well back in Manchester for assistance in trouble shooting, and the Rothera Comms team for their advice and loaning of switch boxes) all the control boxes are now behaving the same way as when we last ran the system in the UK (see here) — and they are now ready to deploy to the field.
After several days of testing, we then finally boxed everything up into our transport cargo boxes so that they can be loaded onto the aircraft to travel our field site.
The fun will be rebuilding the rig and system when it is –20ºC, and then calibrating it for an ice surface rather than rock. Hopefully we have made our lives easier by labelling each component so that it will be a case of following the here’s-one-we-built-earlier approach to assembling the array.
Since our April visit to Svalbard and the first real test of the detection equipment, things have been busy in the electronics lab. Away from the cold we had a chance to review the results of the Svalbard trip – most of the set-up works really well: it is indeed possible to drag detector panels behind a skidoo and detect metal objects hidden under the surface, but certain elements of the system were a little too sensitive to being dragged around in the cold.
To remedy this Liam and John have been busy with a redesign of one of the electronics boxes that form part of the detection system, adding some resilience to the more temperamental parts of the circuit. However we need to check this redesign works as expected – both in the subzero temperatures, and whilst in motion. Whilst another trip to Svalbard might be tempting, summer time in Svalbard means the snow cover is much reduced and rules out the use of skidoos. Instead, in the heat of the hottest UK summer since 1976, we headed for the relatively electrically noise free hills of the near-by Peak District.
Here a suitable field was made available to the team: not too sloping, not too long grass, a little bumpy, not too ferrous (metallic) soil – in its own way a reasonable approximation to the surface of a glacier or a blue ice area (but warmer). This had its own benefits – no need to put on several layers of clothing on every trip outside only to hurriedly remove them as soon as you stepped back inside base, and no Arctic foxes playing havoc with the equipment. No the Peak District is far more civilised than that.
Experimentally though we essentially the same set up: a runway with surrogate meteorites (i.e., metal weights) buried to different depths at 5 to 10 m intervals. The panel and associated electronics are then dragged along this runway at different speeds and with slight adjustments to check the system’s behaviour. As a stand in for a skidoo we went for a 4×4… and everything seem to work pretty much as expected. We’re getting ‘pings’ back from the system for metal objects buried to depths of at least to 20 cm, with less electrical noise than we were seeing before. The tests have allowed us to tune the system before the upcoming field trials in Antarctica later this year.
We’re definitely heading in the right direction! There’s still some tuning to be done, and testing of the different parts of the system in a freezer, but for now all eyes are focussed on preparing for the upcoming Antarctic shipping deadline.