09 February 2015
‘Crime scene’ at Blood Falls – a rusty reddish-brown, stream flows from the Antarctic Taylor Glacier, and into Lake Bonney. Extremely salty water containing iron sporadically seeps through small cracks in the icefall and oxidises instantaneously, giving the liquid its bloody hue – the so-called Blood Falls. Its source, also the object of intense scientific interest, is a sub-glacial lake of unknown dimensions, covered with a thick layer of ice, situated a few kilometres from its small outlet at Blood Falls. It is believed that the lake’s water has been entirely cut off from the outside world for about two million years.
Jill Mikucki/© University of Tennessee Knoxville.
The two-metre IceMole is prepared for its mission and completely decontaminated in a workshop at McMurdo Station. From here, it is transported to the glacier by helicopter.
Marco Feldmann/© FH Aachen.
Moving at one metre per second at a 65-degree angle, the IceMole gradually melts its way towards its goal, located at a depth of 16 metres: a glacier crevasse that carries brine from a sub-glacial lake to the outlet at Lake Bonney.
Without water, there can be no life as we know it. This principle applies both to Earth and to other celestial bodies. Water that has been lying hidden under a thick sheet of ice for millions of years can tell us something about the origin and development of life. But if one wants to recover a sample of this water, care has to be taken that no microorganisms from the surface are introduced and that the sample and underwater habitat are not contaminated. For the very first time, the Enceladus Explorer (EnEx) project, operated by the German Aerospace Center (Deutsches Zentrum für Luft- und Raumfahrt; DLR) Space Administration, has succeeded in using a melting probe – the Aachen University of Applied Sciences (Fachhochschule [FH] Aachen) 'IceMole' – to extract an uncontaminated, subglacial water sample and bring it to the surface. What has now been achieved at Blood Falls in Antarctica will ultimately be achieved on Saturn's moon Enceladus as well. To help achieve this, the EnEx project is being continued throughout 2015.
"We are through"
Situation report – 30 November 2014 at 15:30 New Zealand time; location: southern Antarctica, 77 degrees 43 minutes south, 162 degrees 16 minutes east, on Taylor Glacier; outdoor temperature: -10 degrees Celsius. The IceMole has been melting its way into the glacier for 15 hours, at a speed of one metre per hour. The IceMole is a two-metre-long rectangular tube surrounded by heating elements. At its tip is a melting head with 16 heating elements and an ice screw that draws the probe into the ice. The mole uses a cable to maintain contact with the base station on top of the glacier. On Taylor Glacier, four German scientists are sitting in a small tent following the curves – the vital signs of the IceMole – on their monitors. Everything looks completely normal; then, several curves change simultaneously. The electrical conductivity of the meltwater at the tip of the IceMole increases significantly. The temperature of the melting head increases and its tunnelling speed decreases. First, the scientists stop the IceMole. Thus far it has melted its way 16 metres into the glacier at an angle of 65 degrees. Is this the breakthrough? Have the scientists reached their destination?
They have been working towards this moment for three years, melting their way through the Morteratsch Glacier in the Swiss canton of Graubünden and the Canada Glacier in Antarctica. Have they now broken through into the course that transports water out of the glacier to Blood Falls? The EnEx project's engineers now consult with United States scientists from the National Science Foundation (NSF) who are working on the Minimally Invasive Direct Glacial Exploration (MIDGE) project. The US microbiologists will investigate the glacial lake samples brought up by the IceMole. They are all in agreement; the IceMole has made it through and the sampling can begin. This means that, for the first time ever, scientists have performed a minimally invasive extraction of contamination-free brine from a subglacial lake. "One of the more exciting aspects of this project was working with the German EnEx Team. Their keen understanding of the needs of space exploration was key in developing a clean approach for sampling the Blood Falls subglacial environment. Not only is clean access important from a scientific, sample integrity perspective, it is so important that we do our best as explorers to protect Antarctica's pristine environment," recalls Jill Mikucki, a geomicrobiologist at the University of Tennessee, Knoxville (USA) and leader of the MIDGE project.
A rusty brown, blood red stream flows out of the Taylor Glacier into Lake Bonney in Antarctica. Extremely salty, ferrous water sporadically flows out through small cracks in the icefall. It is immediately oxidised, which gives the water a bloody colour – hence the name, Blood Falls. The source and scientific object of their interest is a subglacial lake of unknown size, overlain by thick ice, lying several kilometres away from the small outlet at Blood Falls. It is thought that the water in the lake has been completely cut off from the outside world for two million years. What 'inhabitants' live down there? Mikucki believes that there are organisms uniquely adapted to living in permanently cold, dark and salty conditions. How have they adapted to this environment? Thanks to EnEx, it will be possible to answer these and other questions in the near future and solve the riddle of the mysterious Blood Falls..
Blood Falls 'under investigation'
A rusty brown, blood red stream flows out of the Taylor Glacier into Lake Bonney in Antarctica. Extremely salty, ferrous water sporadically flows out through small cracks in the icefall. It is immediately oxidised, which gives the water a bloody colour – hence the name, Blood Falls. The source and scientific object of their interest is a subglacial lake of unknown size, overlain by thick ice, lying several kilometres away from the small outlet at Blood Falls. It is thought that the water in the lake has been completely cut off from the outside world for two million years. What 'inhabitants' live down there? Mikucki believes that at least 17 different types of microbes live there under extreme conditions. How have they adapted to this environment? Thanks to EnEx, it will be possible to answer these and other questions in the near future and solve the riddle of the mysterious Blood Falls.
From Blood Falls to Enceladus
The success in Antarctica gives the entire EnEx project extra impetus. The EnEx joint project, which runs until the end of March 2015, reached its first milestone with the successful deployment at Blood Falls. The combination of widely varying technologies for use under extreme environmental conditions has been successfully put to the test in EnEx, and a further development will take place as part of the EnEx Enceladus Explorer initiative. DLR Project Manager Oliver Funke is placing particular emphasis on an autonomous navigation process for this: "If EnEx is deployed on Enceladus, it will have to find its way from the surface to a water-bearing region in the ice crust of the Saturnian moon completely autonomously. Furthermore, it will have to reliably identify obstructions in the body of ice, such as voids or meteorites, and make its way around them. This means that a robust, autonomous navigation process is a key technology for EnEx, the development of which is absolutely necessary for carrying out such a space mission in future."
No ice-melting probe in the world could do this – until now. With NASA's cancellation of the development of CryoBot, the EnEx IceMole is currently the only one of its kind. How will the probe find its way through the ice to its target? "Acoustic navigation methods based on ultrasound and enhanced with inertial navigation and magnetometer measurements have achieved good results to date. These will now be developed into the desired key technology that can cope with the challenges of the environmental conditions on Enceladus," explains Funke.
En route to the water, the probe will be expected to determine its attitude and position, measure the distance to its target, calculate the optimum path (taking into account risk, range and energy expenditure as it does so), send this data to the surface station via a cable connection, and avoid any obstacles in the ice. Scientists from the Bundeswehr (German Armed Forces) University Munich, Braunschweig University of Technology (Technische Universität Braunschweig), Aachen University of Applied Science, Aachen University, the University of Wuppertal (Bergische Universität [BU] Wuppertal) and the University of Bremen (Universität Bremen) are working on this complex 3D navigation solution under the EnEx initiative.
Last modified:16/05/2018 10:00:44