National Geographic aired “Journey to an Alien Moon” as part of its “Explorer” series last night. It describes how the first proof of Europa being an icy moon was obtained from Galileo spacecraft, how life was found to exist in various extreme environments on earth, and how ENDURANCE could be a precursor to smaller under-water robots that could be sent to Europa in search of life-forms.
Thank you for following my blog and for your comments and questions. I have been aiming to write a wrap-up/summary post since long but other tasks have kept me from it. Here I summarize our achievements for 2008 and 2009.
ENDURANCE (Environmentally Non-Disturbing Under-ice Robotic Antarctic Explorer) is a hovering autonomous underwater vehicle. It was developed under NASA’s ASTEP (Astrobiology Science and Technology for Exploring Planets) program by Stone Aerospace as a platform for developing and testing technologies for discovery of life forms on watery moons such as Europa.
Europa is one of Jupiter’s satellites and there is strong evidence that it has a rocky core separated by saline liquid water from an ice/water crust about 80-170 km thick.
Some of the closest analogues to Europa’s ice-covered saline ocean on earth are the lakes in the McMurdo Dry Valleys in Antarctica. The McMurdo Dry Valleys are the largest ice-free region in Antarctica with a total area of about 4800 square kilometers. These dry valleys are a polar desert environment with mean annual temperatures of the valley floor between -30 Celsius to -14.8 Celsius and precipitation of less than 10 cm per year. There are about 20 lakes in the Dry Valleys almost all of which maintain a perennial ice-cover (2.8-6.0 m) over liquid water. The low temperatures, the perennial ice-cover, and the presence of microbial life make the lakes in the Dry Valleys an ideal environment for testing the concepts and technology for discovering life-forms on Europa.
One such lake, Lake Bonney, was chosen for field testing of ENDURANCE.
ENDURANCE performed scientific missions over 10 weeks ( 4 weeks in 2008 and 6 weeks in 2009) in Lake Bonney. With ENDURANCE we developed and demonstrated the technology for exploring under-ice lakes for life-forms.
1. Our vehicle was able to reach within five meters of a specified target and came back to within five meters of the melt-hole after traveling a distance of as much as 3.2 km.
2. We developed a visual homing algorithm that allows the robot to distinguish a blinking light source and use it to rise through a melt-hole with tight clearances.
3. We developed a profiling system that can collect bio-geochemical data and take lake-bottom images along the entire depth of the lake and at any specified location in the lake.
4. We obtained bathymetric maps of the underwater part of Taylor glacier and the lake bottom using sonars. This is the first time that such a detailed map has been constructed.
5. We obtained close-up visual imaging of the underwater part of Taylor glacier at selected locations.
If you are interested in more details, please visit my publications page.
Today was a feast for the senses. We began the day by an excellent breakfast served at our Bed and Breakfast. Fresh tomatoes, eggs and fruit have never given me more pleasure. Peter flew back today morning. He had suggested visiting Riccarton Bush, an old growth forest in the middle of Christchurch. Chris, Kristof and I took a leisurely walk down there. It turned out to be an excellent choice. The trees, bushes, bugs and birds were a pleasure to the eyes, the wind and warm sun a pleasure to feel, the varied bird sounds a pleasure to the ears, the forest smells a pleasure to the nose, and the excellent food in the cafe a pleasure to the sense of taste.
I am at a loss of words to express how great it was to be there, after almost 2 months of not seeing a single plant or animal life form.
Peter, Chris, Kristof and I fly to Christchurch today in a c-17. Rest of the team flies out on the 11th after finishing packing and shipping the robot to the U.S.
I have been ready to leave now that everything I needed to do is done. However, I woke up in the morning feeling rather sad. I have met many interesting, intelligent, eccentric, and wonderful people here, had many interesting conversations and discussions, learned something useful from everyone I met, and now I may never meet many of these people again.
We flew into McMurdo today. I was both relieved and sad to leave Lake Bonney. I have had one of the most amazing experiences of my life in the past 40 days at Bonney. I struggled through being sick and cold when I arrived; the team worked its way through a myriad of problems; the end result was a very successful season whose accomplishments exceeded all expectations. I have formed a strange kind of attachment with the lake and the valley and it made me sad to think that I may never be here again. However, I was relieved to leave – no more being cold all the time, eating bread and cheese for lunch every day, working 14-17 hour days, peeing in a bottle and pooping in a stinky bucket.
We got together in the evening to celebrate. Below is picture (thanks to Maciej and Rachel).
We ran our last mission mission today. In addition, we also tested automated profiling, and ran automated profiling missions. Everything went smoothly and we are one step closer to running complete science missions (including profiling) autonomously in addition to bathymetry missions.
We also managed to do a reasonable amount of robot disassembly and packing work today.
John thought that it would be a good idea to profile the narrows again so that he could see the variation in properties with respect to time. We profiled the narrows again yesterday. This time, the mission seemed very easy and went very smoothly. Below is a plot of the narrows (from Bill) using the data from the previous run.