PostHeaderIcon Nasa flies three decommissioned military drones over active volcano

A Nasa research team has been flying unmanned aerial vehicles(UAVs) into the sulphur dioxide plume of the active Turrialba Volcano in Costa Rica.

The team from Nasa’s Ames Research Centre used three Dragon Eye UAVs from the United States Marine Corps to fly into the volcanic plume and along the rim of the volcano’s crater in a series of flights in March 2013. The aim of the mission was to study the volcano’s chemical environment to improve the remote sensing capability of satellites and computer models of volcanic activity.

The drones flew very close to the rim of the volcano, the summit of which is around 3,200 metres above sea level, as well as several hundred metres above that. During the flights, the team compared the data they gathered relating to the concentrations of sulphur dioxide with that from the Advanced Spaceborne Thermal Emission and Reflection (ASTER) instrument, attached to the Terra satellite. The plan is to develop computer models using the data to improve global climate predictions, safeguard airspace, and mitigate environmental hazards – such as volcanic smog or “vog” — for people who live near volcanoes.

In addition to measuring sulphur dioxide, the models need to take into account the intensity of volcanic activity near the eruption vent — this involves collecting data relating to the height of the ash plume as well as the temperatures over the vent. This will allow for more accurate predictions of the behaviour of volcanic eruptions.

Getting this data is particularly challenging, since volcanic ash — as many discovered when the Icelandic volcano Eyjafjallajökull erupted in 2010 — poses a serious risk to aircraft engines.

David Pieri, the project’s principal investigator and a research scientist at Nasa’s Jet Propulsion Laboratory, said: “It is very difficult to gather data from within volcanic eruption columns and plumes because updraft wind speeds are very high and high ash concentrations can quickly destroy aircraft engines. Such flight environments can be very dangerous to manned aircraft. Volcanic eruption plumes may stretch for miles from a summit vent, and detached ash clouds can drift hundreds to thousands of miles from an eruption site.”

Because of these challenges, UAVs with electric engines — which don’t tend to intake huge amounts of air (and therefore ash) — can be an effective means of studying volcano. The Dragon Eye drones being used for this study are small vehicles, with a wingspan of a little over a metre and a weight of 2.7kg, which can carry a 500g instrument payload for up to an hour within the volcanic plume.

The drones were loaded with instruments including infrared cameras, sulphur dioxide sensors, and atmospheric sampling bottles

Matthew Fladeland, airborne science manager at Ames, said: “By taking these retired military tools, we can very efficiently and effectively collect measurements that improve Nasa satellite data and aviation safety.”

Next year the team plans to use the much bigger Sierra UAV, which weighs 180kg and can carry a payload of 45kg. It will be able to carry a mass spectrometer to measure a broader range of gases — including carbon dioxide, hydrogen sulphide, helium, and sulphate nanoparticles — spewing from the volcano. In the long term, the team wants to develop a means of sampling volcanic plumes as high as 9,150m above sea level following large, explosive eruptions.