- Press Release
- Dec 9, 2022
Keith Cowing’s Devon Island Journal – 28 July 2002 Drilling into permafrost and leaving footprints for eternity
I started the day out by drilling a dozen holes into the ground for a dozen metal anchors. One-meter lengths of rebar were then to be placed in the holes. Turnbuckles and aircraft cable would then anchor the greenhouse to these rebar anchors. A rock foundation was also being built around the platform – not only to help secure the platform in place, but also to reduce the amount of wind that could get underneath the structure.
The greenhouse and its support platform itself weigh well over two tons. All told, taking the weakest components of the new anchoring system into account, this would add well over a ton of additional ‘hold down’ force.
We were already rather confident in the ability of the greenhouse to stay put – even in high winds. Winds can exceed 100 kph here during the worst weather. I was standing inside the greenhouse the other day when the weather station (sample weather report) showed 70 kph winds blowing outside. You could not feel the slightest vibration in the greenhouse. Indeed, I was surprised at just how quiet it was inside given the howling wind outside.
The drill I used was flown in specially from Resolute for this task. Several day before, two geophysicists from the University of Calgary were digging pilot holes around camp in preparation for surveys they were going to do. I asked them if they’d like to dig one in back for the greenhouse so I could see where the permafrost was. After about half a meter they struck solid ice: permafrost.
Given the depth and angle of the holes I needed to drill – and the amount of frozen ground I’d drill through, I was confident that the anchors would provide adequate strength.
Drilling though the thawed soil was rather straightforward. There was no mistaking the permafrost when I hit it. At this point I needed to put my entire body weight – and all the strength I could muster to help force the drill through the remaining permafrost. After half an hour or so I was done.
Permafrost is defined as soil or rock that remains below 32F/0C for two or more years. It is formed when the ground cools sufficiently over the course of winter to produce a frozen layer that remains frozen throughout the following summer. Permafrost is defined by its composition but rather by the temperature it retains over the course of a year. Permafrost can range widely in its composition. It can contain over 30% ice or contain almost no ice at all. It can lie underneath several meters of snow or be found underneath surface areas with little or no snow.
Nearly a quarter of Earth’s exposed surface has permafrost beneath. Estimates by the Geological Survey of Canada show that permafrost on Devon Island can be between 100 and 500 meters thick. While we have yet to drill on Mars, it is almost certain (based on satellite observations) that large amounts of water ice are found below the surface of Mars – as permafrost.
On Devon Island the upper half-meter or so of the surface thaws in the summer. However the frozen layer beneath serves to keep the melted water at or near the surface. As such, you need to build things differently here than you would further south. We built our greenhouse atop multiple wooden block footings placed directly on the ground so as to allow the entire structure to ‘float’ as the ground thaws and then freezes each year.
We went out of our way to minimize disturbances to the area immediately around the greenhouse. The upper, active layer of ground here is vulnerable to environmental damage. Tracks left by airplanes or motorized vehicles can persist for many, many years. As such, great care is taken by the HMP team to be thoughtful about where they traverse the surface. ATV trails have been established in heavily traveled areas and everyone makes certain to stay within these tracks whenever possible. If a region can be reached on foot, then every attempt is made to do so.
Marks left in the permafrost by human activity can persist for a very long time – centuries in some cases. Given the very slow pace at which life grows in this environment, and the thin grasp it has on survival in the first place – it can taken an immense period of time for life to erase these points of damage.
Contrast this with the marks made by humans on the lunar surface. Since the 1960’s it has been commonly expressed that the footprints left by the Apollo astronauts will last for “a million years”. This was based, no doubt, on a quick guess by someone familiar with models of micrometeoroid erosion of the lunar surface. This is the only ‘weathering’ process that could serve to erode these footprints. While more refined models developed since may expand or contract this value, it is certain that humanity’s tracks will persist for an immense period of time.
Quicktime panorama: Center of Base Camp 19 July 2002. 360 degree pan. R-L: Office Tent, Mess Tent, webcam, Comm Tent, Argo ATV, Tool Tent, The Fortress, Airstrip, Greenhouse, Tent City [Download]
Unlike the human marks made in the arctic, which we’d all like to avoid making – and remove if at all possible – the marks made by humans on the Moon may, in contrast, become something we seek to preserve. Picture future lunar tourists wanting to see the Apollo 11 landing site for themselves and you can quickly imagine what steps would have to be taken to keep them from stomping all over history. Similar concerns confronted the discoverers of ancient hominid footprints found in volcanic ash in Africa.
One world’s human damage is another’s history.
- NASA Haughton-Mars Project
- SpaceRef Mars on Earth coverage
- Arthur Clarke Mars Greenhouse
- 17 Jun 2003: Preface: Moving from Green to Grey
- 3 Jul 2003: Waiting in Resolute
- 3-5 July 2003: Arrival and Getting to Work
- 6 July 2003:Getting in the Groove
- 7 July 2003: Part 1: Being here – and being there.
- 7 July 2003: Part 2: Getting Out of Base Camp
- 8 July 2003: Infrastructure
- 9 July 2003: Re-connected; Planting Seeds
- 17 July 2003: Rover Arrival
- 18 July 2003: Wind
- 19 July 2003: Illness, Good Food, and Morale
- 20 July 2003: Arctic Memorials and Starship Yearnings
- 20 July 2003: Going Home
- 21 July 2003: Departure – and One Last Dedication
- 24 July 2003: 24 July 2003: Homeward Bound – In Slow Motion
- 26 August 2003: Home +30
- 8 Jul 2002: Arrival
- 9 Jul 2002: Getting acquainted – and down to work
- 10 Jul 2002: Mars carpentry
- 11 Jul 2002: Lexan Kites, shotguns, and Driver’s Ed
- 12 Jul 2002: Building and exploring
- 13-15 Jul 2002: Building a Mars greenhouse on Earth
- 16 Jul 2002: Sealing Greenhouses on Earth – and Mars; 6 Wheeled Rovers
- 17 Jul 2002: Greenhouse Dedication, Fishing, and Mystery Food
- 18 Jul 2002: Giving Blood, Eternal Light, and an Evening Commute
- 19 Jul 2002: The Hottest Place on Devon Island, T-shirts, a Star Trek hello
- 20 Jul 2002: Mars Airplanes and Communicating With Earth
- 21 Jul 2002: Visiting ministers, missing ‘green’, and crater tours
- 22 Jul 2002: The hottest place on Devon Island
- 23 Jul 2002: Farewells, Birthdays, and Bartering
- 24 Jul 2002: EVAs, movies – and ‘being here’
- 25 Jul 2002: Russian TV, webcam privacy, and being on Mars for a few minutes
- 26 Jul 2002: Cold Feet, Chocolate, and Home Cooking
- 27 Jul 2002: Anchors and anemometers
- 28 Jul 2002: Drilling into permafrost; leaving footprints for eternity
- 29 Jul 2002: Showering near the North Pole; one last look around
- 30 Jul 2002: Departure and arrival
- 31 Jul 2002: Culture shock and flight delays
- 1 Aug 2002: Departure into darkness
- 2 Aug 2002: Green overdose; home at last
- 2 Sep 2002: Home +30