Professor Colin Pillinger and Beagle 2 model. All Rights Reserved Beagle 2

Principal Investigator: C. Pillinger, Open University, United Kingdom.

Link: Beagle 2 web site - http://www.beagle2.com

The heart of Beagle 2 is the Payload Adjustable Workbench (PAW) which is connected to the lander through a robotic arm. The PAW contains a number of instruments for studying the composition of the surface rocks. It also contains the mole, which can burrow under rocks, and the corer-grinder, which can drill into rocks to take samples. The Gas Analysis Package (GAP) will look for the presence of life, either extinct or ongoing. It is located on the lander platform and the robotic arm will feed samples to it for analysis.

When folded up, the Beagle 2 lander resembles a very large pocket watch. This is the state in which it will pass the long journey to Mars. As soon as it comes to a halt on the martian surface, however, Beagle 2's outer casing will open to reveal the inner workings.

First, solar panels will unfold: they will catch sunlight to charge the batteries which will power the lander and its experiments throughout the mission. Next, a robotic arm will spring to life. Attached to the end of the arm will be Beagle's PAW (Payload Adjustable Workbench) where most of the experiments are situated. These include a pair of stereo cameras, a microscope, two types of spectrometer (Mössbauer and X-ray), and a torch to illuminate surfaces. The PAW also houses the corer/grinder and the mole, two devices for collecting rock and soil samples for analysis.

The robotic arm will stretch and rotate to give the two stereo cameras a good panoramic view of the landing site. After taking some shots, the cameras will take close-up images of nearby soil and rocks as potential candidates for further analysis. When a suitable rock has been chosen, the PAW will be rotated until the grinder is in position to grind away the weathered surface. The PAW can then be repositioned for the microscope or spectrometers to analyse the freshly exposed material.

When a rock looks particularly interesting, a sample will be drilled out with the corer and taken to the Gas Analysis Package (GAP) inside the shell of the lander by means of the robotic arm. The mole carried on the back of the PAW will also collect soil samples and return them to the GAP.

The Gas Analysis Package

This is where investigations most relevant to detecting past or present life will be conducted. The instrument has twelve ovens in which rock or soil samples can be heated gradually in the presence of oxygen. The carbon dioxide generated at each temperature will be delivered to a mass spectrometer, which will measure its abundance and the ratio of carbon-12 to carbon-13. The mass spectrometer will also study other elements and look for methane in samples of atmosphere. The temperature at which the carbon dioxide is generated will reveal its nature, as different carbon-bearing materials combust at different temperatures.

The Environmental Sensors

A variety of tiny sensors scattered about the Beagle 2 lander will measure different aspects of the martian environment including: atmospheric pressure, air temperature and wind speed and direction; ultra-violet (UV) radiation; dust fall out and the density and pressure of the upper atmosphere during Beagle 2 ‘s descent through the atmosphere.

Two Stereo Cameras

Will provide digital pictures from which a 3D model of the area within reach of the robotic arm may be constructed. As the PAW cannot be operated in real time from Earth, this 3D model will be used to guide the instruments into position alongside target rocks and soil and to provide information on the geological setting of the landing site.

The Microscope

Will pick out features a few thousandths of a millimetre across on rock surfaces exposed by the grinder. It will reveal the texture of the rock, which will help determine whether it is of sedimentary or volcanic origin.

The Mössbauer Spectrometer

Will investigate the mineral composition of rocks by irradiating exposed rock surfaces and soil with gamma-rays emitted by an isotopic source (cobalt-57), and then measuring the spectrum of the gamma-rays reflected back. In particular, the nature of iron minerals in the pristine interior and weathered surface of rocks will be compared to determine the oxidising nature of the present atmosphere.

The X-ray Spectrometer

Will measure the elemental composition of rocks by bombarding exposed rock surfaces with X-rays from four radioactive sources (two iron-55 and two cadmium-109). The rocks will emit lower energy X-rays characteristic of the elements present. Rock ages will be estimated using the property that the isotope potassium-40 decays to argon-40. The X-ray spectrometer will provide the potassium measurement and the GAP will measure argon trapped in rocks.

The Mole

Will be able to crawl up to several metres across the surface at the rate of 1 cm every six seconds. Once it has reached a boulder, it will burrow underground to collect samples in a cavity in its tip. Alternatively, the PAW can be positioned such that the mole will burrow vertically underground to collect samples possibly 1.5 m below the surface.

The Corer/Grinder

Consists of a drill bit which can either be moved over a surface to remove weathered material, or be positioned in one spot to drill a core of hopefully pristine sample.

Text Source: European Space Agency - Press Kit
Mars Express web site: http://mars.esa.int

Image Source: Beagle 2
Beagle 2 web site: http://www.beagle2.com