Thanksgiving Forecast
Phoenix Mission Overview
The Phoenix Mars Lander, the first mission to study a polar region of Mars at ground level, launched from the Kennedy Space Center aboard a Delta II rocket at 5:26 a.m. EDT on August 4, 2007. After landing near the northern polar cap on May 25, 2008, in an area known as Vastitas Borealis, Phoenix will spend 90 days probing Mars' soil and atmosphere for clues about the history of water and to see whether the environment could support life.
Phoenix uses a 2.35-metre robotic arm to dig into the soil scooping up samples for analysis by its onboard chemistry set. Scientists can test to see whether the soil is salty, alkaline, oxidizing, and has complex organic molecules necessary for life. Phoenix will be the first mission to touch and sample the water on Mars, which is thought to be frozen in the northern permafrost just below the surface.
The Mars Exploration Rovers, Spirit and Opportunity, have already sent evidence that water likely existed billions of years ago on Mars. Satellites orbiting the planet have also found strong evidence of permafrost ice in the polar regions. Unlike the Spirit and Opportunity rovers, the Phoenix lander is stationary, since water ice is probably spread uniformly throughout the northern plains.
The Search for Water
Following the clues for water is like science detective work. Water is key to many scientific questions about Mars:
- Have there ever been-or are there now-living organisms on Mars?
- What can Mars teach us about climate change?
- How do geological processes differ on Mars and on Earth?
- How can we prepare to explore Mars?
Water is a major agent of climate and geology, a precursor for life, and a potential resource for human explorers.
Canada's Contribution to Phoenix
Mars Weather Reports
Canada developed and built the meteorological station (MET) on Phoenix that records the daily weather of the Martian northern plains using temperature, wind and pressure sensors, as well as a light detection and ranging instrument, or lidar. The data improves models of the Martian climate and predict future weather processes, paving the way for future exploration missions. This information may also add to scientists' understanding of Earth's dynamic polar regions as they compare the two planets.
Resembling a bright green laser, the lidar probes the "boundary layer" of the Martian atmosphere. This is the turbulent layer of the atmosphere about seven to ten kilometres above the surface. The lidar also provides information about the structure, composition and optical properties of clouds, fog, and dust in the lower atmosphere, up to 20 kilometres above the landing site.
The Canadian Space Agency invested $37 million for the design, construction, operations, and scientific support of the MET station, which was tested at the David Florida Laboratory in Ottawa.
Robotic Arm
Alliance Spacesystems' next robotic arm is aboard NASA's Mars Phoenix Lander, where it will trench the Martian surface like a mini-backhoe to uncover an expected layer of rock-hard water ice.
Endowed with four degrees of freedom and a reach of 2.3 meters, the aluminum and titanium device weighs less than 9.7 kilograms. At the business-end of the arm is a garden trowel-size scoop for trenching. A powered rasp is mounted on the scoop to penetrate, break up and retrieve the hoped-for water-ice samples for scientific examination by lander instruments. A camera is also mounted on the arm to give scientists on Earth a close-up view of sediment and ice layers in the trench wall.
Source: MDA
Legend
Clouds - On Mars, these are made up of ice crystals formed from water, or, under the exceptionally cold conditions of a Martian winter, carbon dioxide. Dust storms, which can occur on Mars for several months at a time, can turn the clouds a yellow or red colour.
Diamond dust - This is the name given to the sparkling clouds of tiny ice crystals that appear to fall out of a cloudless sky. The ice crystals can disappear before they reach the ground through a process called sublimation.
Dust is a major factor in the climate. Dust particles are small and fine, but sharp. Dust can be carried up by winds into the atmosphere in a number of ways. See also dust devil, dust storm, and dust plume. The Canadian-built lidar aboard Phoenix can detect dust in the atmosphere.
Dust devil - A localized whirling wind, like a mini-tornado, which can carry dust up to 10 kms into the atmosphere.
Dust plume - A non-rotating wind raises the dust straight up into the atmosphere.
Dust storm - Loose dust is borne aloft into the atmosphere by high-speed winds. Dust storms can cover very large areas and have been known to cover the entire planet.
Fog - Tiny ice crystals suspended in the air near the planet's surface.
Frost - The formation of ice crystals from water vapour as it comes in contact with a surface at a temperature below the freezing point.
Sublimation - The term used for a change from water ice (solid) to water vapour (gas). The process is due to a combination of factors such as radiation from the sun, temperature, pressure, and other atmospheric conditions.
Sun - The planet's surface temperature is governed by heating by solar radiation, moderated by the effects of the atmosphere, which can act like a blanket trapping heat that would otherwise escape to space. Mars has a much thinner atmosphere than Earth so this "Greenhouse Effect" is much weaker. Being further away from the sun means that Mars also receives less solar radiation. These two effects combined mean that temperatures on Mars are, on average, colder than Earth.
Wind - Winds are caused by the flow of the atmosphere from high pressure to low pressure. Scientists have direct information about the winds on Mars only from the Pathfinder and Viking lander missions. Winds at the Phoenix landing site will be measured by the telltale instrument, which sits at the top of the Meteorological Station's mast. Simulations of the Mars atmosphere suggest that winds here will be fairly light, rarely more than 25 kilometres per hour. However, during sudden gusts and dust storms, winds of up to 483 kilometres per hour may be possible.
Source: NASA/JPL-Caltech/University of Arizona/Canadian Space Agency. Wind by the University of Aarhus, Denmark
