I have just taken a look at the NASA site for an update on the Phoenix mission. The latest news is that the Mars Lander's robotic arm managed to collect its icy soil sample as intended, but will need to adjust its delivery mechanism as most of the sample got stuck in the scoop.
NASA engineers had carried out the required soil scraping activity using a rasping tool. The scooping action had been performed and there was enough Martian soil collected to fill the Thermal and Evolved-Gas Analyser (TEGA), a tiny oven cell. However, images returned from the lander show that much of the soil remained lodged in the robotic arm's scoop after several attempts to coax the sample into the TEGA.
What if the NASA engineers don't manage to fix the scoop mechanism? Will the secrets within that icy soil sample be lost? Well, no, is the answer. It appears that thanks to the Robotic Arm Camera (RAC), quite a bit of information will be able to be retrieved from the close-up colour images taken of the soil sample before and after scooping.
The camera in question employs a charge-coupled device (CCD), and has sets of red, green, and blue light-emitting diodes positioned just above and below the lens to illuminate the target area. Other notable features include a double Gauss lens system and, in a first for an interplanetary spacecraft, an adjustable lens focus thanks to a motor that can set it from 11 mm to infinity. Another motor opens and closes a transparent dust cover.
A team at the Max Planck Institute for Solar System Research in Katlenburg-Lindau, Germany, developed the RAC in collaboration with researchers at the University of Arizona. Though originally built for the Mars Surveyor 2001 Lander mission, which was cancelled in 2000, the RAC was dusted off (metaphorically, as it had been stored in a clean-room) and re-activated for use on Phoenix in 2005.
CCDs have traditionally provided the performance benchmark in terms of image quality in photographic, scientific, and industrial applications but cmos cameras have been playing catch up. And whilst CMOS imaging developments have concentrated on achieving an image quality comparable to CCDs, CCD designers have worked on minimising power requirements and pixel sizes.
In this case the RAC can focus down to 11mm and provide image resolutions of 23 microns per pixel, enabling it to show details 'much finer than the width of a human hair'. Combined with its colour reproduction, its images should be detailed enough to allow scientists to better judge the nature of the soil and water-ice in the trench being dug by the robotic arm, and also to determine any fine-scale layering that may result from changes in Martian climate from images of the trench floor and side-walls.
Interestingly, the Max Planck Society largely financed the RAC's development and integration and the German Space Agency (DLR) has supported the operation of the instrument during Phoenix surface operations since 2007.
European image sensor developments have played a part elsewhere in the Phoenix mission. British company e2v's CCD image sensors were aboard NASA's Mars Reconnaissance Orbiter and captured an image of Phoenix suspended from its parachute as it arrived on Mars. It was a first time that a spacecraft has captured an image of another spacecraft landing on a planetary body.
For the general public, it is these images from the Phoenix mission that have really caught the imagination and kept the mission in the headlines (albeit well after Amy Winehouse's latest exploits in UK papers).
In a speech by NASA Administrator Michael Griffin to the French National Assembly's Parliamentary Group on Space recently, he emphasised the value the US places on multilateral cooperation in space research. Let's hope then that current European research contributions to NASA's programmes get the recognition they deserve.