The Beagle 2 team has selected two potential landing sites on Mars for further study. In the latest issue of the Beagle 2 Bulletin, John Bridges from the Natural History Museum, London, who is leading the landing site study, writes: “The prospective areas are within the Chryse and Tritonis Lacus regions. Both are at low elevation, which gives more opportunity for the parachutes to brake the descent of Beagle 2. The latitude of the two sites, about 19°N, means that the mission will begin during the Martian late spring, when there is more solar energy to charge batteries and nighttime temperatures are relatively high, making it easier to keep the spacecraft warm.

“Chryse is a region of flood channels which have brought materials from the southern highlands down over the northern plains. The Maja Vallis channel area in Chryse is of particular interest because Viking and Mars Orbiter images show the presence of some layering in isolated mesas (elevated flat surfaces, like plateau). Such layers might include hard pans (crust) formed through precipitation of salts from groundwater or ephemeral lakes.

“Tritonis Lacus is on the margin of the Elysium plains and consists of a more eroded landscape. This erosion has left a generally smooth surface which would be suitable for a safe landing.” Selection of the final site will be made in February 2001 based on the outcome of detailed modelling of the landing activity at both sites and after consultation with the scientific community at an international workshop. “We are reviewing all the images we can get from Mars Global Surveyor (NASA’s spacecraft currently in orbit around Mars). The site must be suitable for the science we want to do and be compatible with the entry and descent of Beagle 2,” says Colin Pillinger, Principal Investigator for Beagle 2.

“The delivery of Beagle by Mars Express requires complicated manoeuvres which use extra fuel. So the final selection will also take into account extensive studies to make sure that the implications for the spacecraft are acceptable,” adds Rudi Schmidt, Mars Express Project Manager.

USEFUL LINKS FOR THIS STORY

* More about Beagle II

http://sci.esa.int/marsexpress/mex-beagle2.html

* Beagle II homepage

http://beagle2.open.ac.uk/beagle2/

IMAGES AND CAPTIONS:

[Image 1]
Location diagram for the Beagle 2 landing sites. The landing ellipses are 240 km long.

[Image 2]
Maja Vallis area. The general pattern of flood and sediment passage towards the NE is clear from the
streamlined landforms. Evidence of terracing exposed on the sides of channels is most well developed around
50-51 deg W. The N-S running ridges towards the the east of the figure may be surface expressions of
underlying lava flows. A band of Noachian basement is present around 54 deg W, the Maja Vallis channel cuts
through this at 18 deg N. The landing ellipse is 240 x 20 km in 16 deg WSW/ENE orientation.

[Image 3]
Tritonis Lacus. This shows the generally flat, even surface of the region with isolated mesas and craters.
Sinusoidal projection Viking context image. The landing ellipse is 240 x 20 km in 16 deg WSW/ENE orientation.

[Image 4]
Model of the Beagle 2 lander.