Philae lander

The Central On-Board Computer of the Philae Lander in the Context of the Rosetta Space Mission... 

Scientific Instruments and Subsystems Aboard Philae Lander [2]... 

The Philae lander carries ten scientific instruments panoramic, stereoscopic and descent camera a-p-x-ray spectrometer evolved gas analyser for elemental, molecular and isotopic composition infrared microscope comet acoustic surface and sounding experiment permittivity probe dust impact monitor multi-purpose sensor for surface and sub-surface science magnetometer plasma monitor comet nucleus sounding experiment drill and sample distribution system. 

Fig. 5. Surroundings of the Philae lander after landing on the comet. One of the feet of Philae is seen on the left-side image. Images taken by the CIVA panorama camera.

The starting times and duration of the radio visibility time-windows for the Rosetta spacecraft to establish a radio link with the Philae lander depended on numerous circumstances and factors, such as the executed flight track of the Rosetta spacecraft, the 12.6 hours rotation period of the comet, the landing site, and the orientation of Philae on the comet. Although these time-windows were nominally calculable, Philae had to be prepared also for the worst-case, if there was any deviation fi-om the predictions. 

PWTH Power and thermal control of the Philae lander... 

Theory vs. Reality. Further questions and dilemmas arise in the practical implementation of theoretically optimum-solutions. These include considerations like environmental conditions, mass-, volume-, harnessing- and power consumption limitations, parameters of available components (e.g. radiation hardened components), costs of hardware/software development, implementation, manufacturing, functional validation and system integration. The definition of fault-containment regions [4] within a complex system (e.g. Philae lander) is also an important step in preparing the design concept. 

Central on-board computer of the Philae lander as a fault-tolerant subsystem. 

Both DPUs constantly control the Philae lander, but only the current primary one has effective control. The current secondary DPU can take over the primary role at any time. Role-change and follow-on recovery take place at the level of Elementary Sequencing Items (see below). 

The Central On-Board Computer of the Philae Lander in the Context of the Rosetta Space Mission. Andras Baldzs, from the Wigner Research Centre for Physics in Budapest, Hungary, presented an overview of the major hardware and software design aspects of the central on-board computer of the Philae lander, which traveled over 10 years as the precious payload of the Rosetta spacecraft that recently made the historical encounter with the comet 67P/Churyumov-Gerasimenko. 

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