The underwater glider ‘Challenger’ has completed its journey from Fremantle, Western Australia, to Galle, Sri Lanka. It departed Australia on 5 November and has now been recovered in Sri Lanka.
The glider spent 330 days at sea which is a record for Rutgers University glider missions. It covered a distance of 7,570 km, setting a new world record for an underwater glider flight. This beats Rutgers University's own record of 7,420 km set by another glider, RU27, in 2009. In addition to this, even after 330 days at sea there was virtually no biofouling of the glider, it looked the same as the day it was deployed – give or take a couple of random barnacles.
This journey completes Leg 1 of the Indian Ocean Circumnavigation led by Rutgers University with support from the University of Western Australia at sea and the Universidad de Las Palmas de Gran Canaria on shore.
Challenger was welcomed at a special ceremony in Colombo, Sri Lanka, on October 2, 2017. In attendance to welcome the glider and read its cargo of letters of support for its journey, were Dave Aragon, Travis Miles and Scott Glenn (Rutgers University), Michael Cragun (US Embassy Representative), Hon Eran Wickremaratne (Sri Lankan State Minister for Finance), Hon Bryce Hutcheson (Australian High Commissioner) and IMOS Ocean glider facility leader, Chari Pattiaratchi (University of Western Australia).
This month, Challenger will be redeployed on Leg 2 of the mission, a 7,000 km flight from Sri Lanka back to South Africa, where the team will test new battery packs and the ability of a thruster to help navigate the strong currents of the Agulhas system. The mission is a component of the International Indian Ocean Expedition-2 (IIOE-2).
One year from now, the team hopes to again deploy Challenger on the most ambitions mission to date, a 8,400 km flight from South Africa back to Perth, Australia, during which models of the Antarctic Circumpolar Current will be tested in preparation for even grander missions in the future.
Underwater gliders, like their airborne namesakes, are not propelled by an engine. Movement through the water is achieved through changes in buoyancy. By alternately reducing and expanding their volume, gliders can descend and ascend through the ocean using very little energy. In addition to controlling ascent and descent, rudders on the glider enable its direction to be changed. The glider can descend to 1,000 metres and then rise to the surface to transmit the data obtained. Challenger is piloted by remote control via satellite from Rutgers University and UWA.
The data gathered by Challenger will enable scientists to see how conditions in the Indian Ocean have changed over time. Temperature and salinity at specific depths and locations recorded by Challenger will be compared with measurements taken up to 40 years ago. These comparisons will help scientists to predict ocean conditions and their impact on climate.
As Challenger makes its way across the ocean, its position can be tracked via the IMOS Ocean gliders Facility website or via the Rutgers University site. Tracks are also available through the IMOS Ocean Current website. Measurements of temperature and salinity, made by Challenger at depths up to 1,000 metres, are available in near real time.