Phoenix Mars Lander on track for Aug 2007 launch to the red planets.
Launch: Phoenix will be launched in Aug 2007 from Cape Canaveral Air Force Station in Florida on a Boeing Delta 2925 launch vehicle. After launch, Phoenix will perform various maneuvers to make the transition to the cruise stage. The spacecraft will deploy its solar arrays and re-orient itself in space. A connection to the NASA Deep Space Network will be initialized which will allow communication with Earth. When these maneuvers are complete, the spacecraft will be generating energy from its solar panels and ready to receive further commands from Earth.
Cruise: The cruise phase lasts for approximately 10 months as Phoenix makes its way to Mars. During the cruise phase, the spacecraft verifies the health of its scientific instruments and performs trajectory correction maneuvers (TCMs). The Deep Space Network (DSN) is used to communicate with the spacecraft during these operations. The massive antennas of the DSN are also used to obtain information about the spacecraft's flight path. Often times, the spacecraft will be observed from DSN sites in different parts of the world simultaneously to find its exact trajectory. These measurements are crucial for planning (TCMs).
The initial launch trajectory is intentionally pointed away from Mars so that the jettisoned third stage from the launch vehicle does not impact Mars. The first TCM, performed just 10 days after launch, places the spacecraft on a trajectory towards Mars. The subsequent TCMs are planned to take place much later in cruise phase to correct small errors in the first TCM (see image at right). These errors come from a multitude of sources, including imperfections in the flight model and slight inaccuracies in the DSN measurements. This type of deep space navigation has been used by many other NASA missions, including Mars Odyssey and the recent Mars Exploration Rovers.
Entry-Descent-Landing: In May 2008, Phoenix will slow from a cruise speed of 16,000 mph. Phoenix will use aeroshell braking, parachute descent, and controlled thruster descent to make a soft touchdown on Mars.
At 125 km (78 miles) above the surface, Phoenix will enter the thin martian atmosphere. It will slow itself down by using friction. A heat shield will protect the lander from the extreme temperatures generated during entry. Antennas located on the back of the shell which encases the lander will be used to communicate with one of three spacecraft currently orbiting Mars. These orbiters will then relay signals and landing info to Earth.
After the lander has decelerated to Mach 1.7 (1.7 times the speed of sound), the parachute is deployed. Shortly after the parachute is deployed, the heat shield is jettisoned, the landing radar is activated, and the lander legs are extended. The lander continues through the martian atmosphere until it comes within 1 km (.6 miles) of the martian surface. At this point, the lander separates itself from the parachute. It then throttles up its landing thrusters and decelerates. When Phoenix is either at an altitude of 12 m (39 ft) or traveling at 2.4 m/s (7.9 ft/s), the spacecraft begins traveling at a constant velocity. The landing engines are turned off when sensors located on the footpads of the lander detect touchdown.
Mission:
Surface operations are planned in relation to martian days, which are known as sols. Because Mars rotates slightly slower than Earth, sol is 40 minutes longer than our planet's 24-hour day. A strategic plan is created that outlines operations two weeks into the future. This strategic plan is used to create a more detailed tactical plan which decides surface activities that will take place for the next two sols. Daily science and engineering data is used to assess the status of the strategic and tactical plans, and the plans are updated as necessary.
Immediately after Phoenix touches down on the surface of Mars (sol 0), critical instruments such as the solar arrays and SSI mast are deployed. Later in the afternoon of sol 0, EDL data and MARDI images are sent to Earth. On sol 1, TEGA, MECA and RAC are turned on and checked out, and the RA is deployed. SSI begins taking images of the landing site and the area where the robotic arm will be digging, and MET begins to sample the weather at the landing site.
On sols 2 through 9, the instruments aboard Phoenix continue to take initial measurements. TEGA takes measurements of the martian atmosphere using its mass spectrometer. The RA aquires a sample of martian soil and delivers it to TEGA on sol 4. This sample is analyzed by the differential scanning calorimeter in TEGA on the following sol. Another sample is delivered on sol 7 for analysis using MECA.
The digging operations phase is planned to take place on sols 10-90. SSI and RAC images will be analyzed to determine where the RA should dig. Phoenix will dig for up to 2.5 hours per sol during this period. As the RA digs into the martian surface, SSI and RAC images will help determine when new samples should be delivered to the scientific instruments on Phoenix. Samples will be delivered to TEGA about every 15 cm (5.9 in) or when layering is obvious. The four MECA cells will be reserved for samples from different layers that are expected to be encountered while digging. One cell will analyze a sample from the surface, another will analyze the dry regolith overburden, and one will be kept in reserve for the icy layer. One MECA cell will be kept for a repeat measurement or to examine another layer.
Image Credit: Phoenix Mission, University of Arizona
Launch: Phoenix will be launched in Aug 2007 from Cape Canaveral Air Force Station in Florida on a Boeing Delta 2925 launch vehicle. After launch, Phoenix will perform various maneuvers to make the transition to the cruise stage. The spacecraft will deploy its solar arrays and re-orient itself in space. A connection to the NASA Deep Space Network will be initialized which will allow communication with Earth. When these maneuvers are complete, the spacecraft will be generating energy from its solar panels and ready to receive further commands from Earth.
Cruise: The cruise phase lasts for approximately 10 months as Phoenix makes its way to Mars. During the cruise phase, the spacecraft verifies the health of its scientific instruments and performs trajectory correction maneuvers (TCMs). The Deep Space Network (DSN) is used to communicate with the spacecraft during these operations. The massive antennas of the DSN are also used to obtain information about the spacecraft's flight path. Often times, the spacecraft will be observed from DSN sites in different parts of the world simultaneously to find its exact trajectory. These measurements are crucial for planning (TCMs).
The initial launch trajectory is intentionally pointed away from Mars so that the jettisoned third stage from the launch vehicle does not impact Mars. The first TCM, performed just 10 days after launch, places the spacecraft on a trajectory towards Mars. The subsequent TCMs are planned to take place much later in cruise phase to correct small errors in the first TCM (see image at right). These errors come from a multitude of sources, including imperfections in the flight model and slight inaccuracies in the DSN measurements. This type of deep space navigation has been used by many other NASA missions, including Mars Odyssey and the recent Mars Exploration Rovers.
Entry-Descent-Landing: In May 2008, Phoenix will slow from a cruise speed of 16,000 mph. Phoenix will use aeroshell braking, parachute descent, and controlled thruster descent to make a soft touchdown on Mars.
At 125 km (78 miles) above the surface, Phoenix will enter the thin martian atmosphere. It will slow itself down by using friction. A heat shield will protect the lander from the extreme temperatures generated during entry. Antennas located on the back of the shell which encases the lander will be used to communicate with one of three spacecraft currently orbiting Mars. These orbiters will then relay signals and landing info to Earth.
After the lander has decelerated to Mach 1.7 (1.7 times the speed of sound), the parachute is deployed. Shortly after the parachute is deployed, the heat shield is jettisoned, the landing radar is activated, and the lander legs are extended. The lander continues through the martian atmosphere until it comes within 1 km (.6 miles) of the martian surface. At this point, the lander separates itself from the parachute. It then throttles up its landing thrusters and decelerates. When Phoenix is either at an altitude of 12 m (39 ft) or traveling at 2.4 m/s (7.9 ft/s), the spacecraft begins traveling at a constant velocity. The landing engines are turned off when sensors located on the footpads of the lander detect touchdown.
Mission:
Surface operations are planned in relation to martian days, which are known as sols. Because Mars rotates slightly slower than Earth, sol is 40 minutes longer than our planet's 24-hour day. A strategic plan is created that outlines operations two weeks into the future. This strategic plan is used to create a more detailed tactical plan which decides surface activities that will take place for the next two sols. Daily science and engineering data is used to assess the status of the strategic and tactical plans, and the plans are updated as necessary.
Immediately after Phoenix touches down on the surface of Mars (sol 0), critical instruments such as the solar arrays and SSI mast are deployed. Later in the afternoon of sol 0, EDL data and MARDI images are sent to Earth. On sol 1, TEGA, MECA and RAC are turned on and checked out, and the RA is deployed. SSI begins taking images of the landing site and the area where the robotic arm will be digging, and MET begins to sample the weather at the landing site.
On sols 2 through 9, the instruments aboard Phoenix continue to take initial measurements. TEGA takes measurements of the martian atmosphere using its mass spectrometer. The RA aquires a sample of martian soil and delivers it to TEGA on sol 4. This sample is analyzed by the differential scanning calorimeter in TEGA on the following sol. Another sample is delivered on sol 7 for analysis using MECA.
The digging operations phase is planned to take place on sols 10-90. SSI and RAC images will be analyzed to determine where the RA should dig. Phoenix will dig for up to 2.5 hours per sol during this period. As the RA digs into the martian surface, SSI and RAC images will help determine when new samples should be delivered to the scientific instruments on Phoenix. Samples will be delivered to TEGA about every 15 cm (5.9 in) or when layering is obvious. The four MECA cells will be reserved for samples from different layers that are expected to be encountered while digging. One cell will analyze a sample from the surface, another will analyze the dry regolith overburden, and one will be kept in reserve for the icy layer. One MECA cell will be kept for a repeat measurement or to examine another layer.
Image Credit: Phoenix Mission, University of Arizona