Phoenix (spacecraft)
Phoenix was a NASA spacecraft to explore the planet Mars, which was launched on 4 August 2007, on 25 May 2008 ( UTC) near the northern polar region of Mars ( Vastitas Borealis ) and ended on November 2, 2008 for the last time signals for earth radioed. The probe was part of the Mars Scout Program of NASA, are performed in the smaller and less expensive space probes.
Phoenix based largely on the Mars Surveyor 2001 Lander, who built for a start in 2001 but was not launched in December 1999 after the loss of the previous Mars Polar Lander. Since then, the almost completed probe was stored in a clean room until the decision was made in 2003 to modernize the probe and send it to Mars in 2007. Hence it is also the name of the probe - Phoenix is in the Greek mythology a bird that rises from its ashes.
The mission was led by the University of Arizona, which also provided some of the instruments, while Lockheed Martin was responsible for building the spacecraft and the tests. It was a mission with international contributions from Denmark, Germany, Finland, Great Britain, Canada and Switzerland, and the first in NASA's history, which was headed by a state university. The total budget of the mission, including the launch vehicle and mission execution to November 2008 stood at $ 420 million.
Mission Objectives
Phoenix was in contrast to the rovers Spirit and Opportunity, launched in 2003 a stationary probe. She landed in a region of Mars, where just under the surface from about two to five centimeters depth of the soil should consist of up to 80 percent of water ice on the data from Mars Odyssey. In order to study the ice, Phoenix was able to advance to a robotic arm at a depth of up to half a meter into the ground.
With the measurements of the probe had two objectives: first, to study the geological history of water ice in order to understand the change from the formerly warm and wet to the present cold and frozen Mars. The second goal was the search for clues to possible former life, which could be present in the ice. For the investigations, the probe possessed with the TEGA instrument on several small furnaces, which were filled by the robot arm with samples. After heating the sample, the proportion of water, and carbon was measured; also they were looking for traces of minerals that may have originated in a warm and humid climate. Furthermore, the presence of organic substances was measured.
Other instruments of the probe studied smallest soil particles up to 16 micron size. You have the electrical and thermal conductivity of the particles measured by sensors mounted on the robot arm to thereby draw conclusions about their nature can.
Technology
The startup 670 kg vast Phoenix consisted of a cruise stage and the actual 350 -pound lander, which was in a sheath, consisting of the front heat shield ( Aero Shell ) and the rear heat shield (back shell) existed. The Cruise Stage was only required for the flight to Mars, to supply the spacecraft with energy and maintaining communications with Earth. She was separated five minutes before the entry into the Martian atmosphere (fourteen minutes before landing ), after which the Lander turned in the direction of flight (13,5 minutes before landing ), in 125 km altitude with 5.6 km / s in the atmosphere entered (422 seconds before landing ) and through the Martian atmosphere has slowed to about ten times the acceleration of gravity.
Shortly thereafter ( -203 s ) unfolded 12.6 km altitude a parachute, which reduced the speed to 55 m · s -1 ( ≈ 200 km · h -1). 11 km altitude ( -188 s ) of the front heat shield was jettisoned, the landing legs went from ( -178 s ) and the radar for detecting the surface was activated (-128 s ). 880 m above the bottom of the chute, and the rear heat shield was separated (-31 s ) and the braking ignited engines (-10 s ); this slowed the lander from further and made it possible to control for a horizontal landing on his feet. The power supply of the probe is provided by round solar panels that were folded out about 25 minutes after landing. For communication between the Lander had only a small UHF antenna. The wireless connection to the earth was usually made via one of the Mars orbiter via store-and -forward technology. Only during the landing phase Mars Odyssey was used directly as a relay station.
Instruments
The probe was 55 kg scientific payload, an extensive arsenal of instruments:
Mission History
On 4 August 2003, NASA chose as part of its Mars Scout program of several proposals the concept of Phoenix lander, which is already almost finished Mars Surveyor Lander was revised and equipped with modernized instruments. This could cost in the construction of the Phoenix will be saved so that the probe actually quite challenging in the context of the Mars Scout program could be financed.
To prevent possible hazards to go out of the way, since November 2006 the available Mars Reconnaissance Orbiter had examined the selected landing sites with its high resolution camera accurately.
Phoenix was sent on August 4, 2007 at 09:26:34 UTC clock with one day delay of a Delta II 7925 rocket on a journey to Mars. One month after the start of the regular review of the instruments was completed, in particular the communication for landing.
The landing was not having an airbag landing system, but with the help of brake engines, who worked as the Viking probes to touchdown on the planet's surface as opposed to the Mars rovers Sojourner, Spirit and Opportunity. The primary mission of the lander ended in accordance with the plans in November 2008.
The perfect landing took place May 25, 2008 at 23:38 UTC clock. Because of the distance from the Earth of 276 million kilometers, the first radio signals from the landing site could wait 15 minutes later, at 23:53:44 UTC clock is received on Earth. To record sure the telemetry data during the critical EDL phase (Entry, Descent and Landing ), the orbits of active Mars orbiter had been adjusted so that the signals of the probe from all three orbiters (MRO, Mars Express and Mars Odyssey ) could be received.
The first images of the landing site, transmitted by the Mars Odyssey orbiter, met on May 26 at 01:53 UTC clock in the JPL control center (Jet Propulsion Laboratory ) in Pasadena one.
The commissioning of the robot arm of the probe was delayed by one day, as the communication system of the MRO (Mars Reconnaissance Orbiter ), over which should receive the probe commands from Earth, had gone out of yet unknown reasons in a standby mode. The probe automatically then worked from a pre-defined camera recording sequence. Since May 28, the spacecraft Mars Odyssey was used as a transfer station, as long as the problems with the MRO were not solved. The robot arm was commissioned in stages and created additional pictures for a panorama. On 20 June 2008, the chief scientist of the mission, Peter Smith gave at the University of Arizona, notes on the discovery of water ice known. The ice was several inches deep came during excavations of Phoenix ' dipper in the subsurface of the landing site for days. On 1 August 2008 the media reported a success in the search for water: A soil sample was collected with the shovel and heated in an oven; there was water vapor. Thus it is clear that the soil sample has included ice and water definitely occurs on Mars.
On 5 August 2008 the media reported that the wet chemical laboratory ( MECA ) has found significant amounts of perchlorates in a soil sample. On Earth, perchlorates are found in the arid desert regions.
On September 3, were with the Canadian lidar at a height of about 3 kilometers shower of ice crystals / snow detected that fell from passing clouds. Due to the temperature in the atmosphere, it must have been to water ice, the sublimed again at an altitude of about 2.5 kilometers before reaching the ground.
The onset of October 2008 beginning of winter in the landing area of the probe on the neighboring planet was heralded by the reduced sunlight with plummeting temperatures. The heating of the probe needed more and more power from the power supply. The main camera and meteorological instruments continue to operate, was parked a part of the heating module in October 2008. As a result, the robot arm (RA ) and the melting furnace ( TEGA ) of the probe were shut down. It was hoped that this measure be extended again with the resulting savings in energy operating time. On 2 November 2008, the probe for the last time sent scientific data before contact was lost. On November 10, the end of the mission was announced.
Between January and May 2010, NASA tried several times to take by the Orbiter 2001 Mars Odyssey radio contact with Phoenix, but this did not succeed. High resolution images of Mars Reconnaissance Orbiter on May 7, 2010, shortly before the summer solstice, pointed out that the solar panels were bent or broken by Phoenix under the ice load during the Martian winter, which the lander was permanently inoperable.
Images of the Martian surface
One of the first pictures of the Martian surface from Phoenix
Near Phoenix found polygonal structures in accordance with the frost -patterned ground on Earth
The robot arm has exposed ice.