Frequently asked questions
Inputs to this FAQ list are welcome. Please send them to Dr. Heiner Klinkrad.
Question:
While processing a flux analysis in the target orbit scenario, the MASTER-2009 flux
browser issued the warning: 'Valid On-line Cell Passage buffer dimension reached during
flux shooting!' What does it mean and how are my flux results affected by this warning?
Answer:
The MASTER-2009 flux browser computes debris fluxes based on a stochastic population reproduction.
During this calculation process a situation may occur where the flux shooting fails to reach a
pre-defined standard deviation for a certain debris source and diameter threshold. If the flux
browser issues this warning, your computation result may differ more than 10 percent compared to
a deterministic flux calculation approach. You may try to use a slightly different target orbit
for your analysis, e.g. use a different value for the right asc. of asc. node (the software averages
over this value anyway with the exception of population clouds) or slightly increase the eccentricity
if your initial value was very close or equal to 0.
Question:
What size thresholds of debris populations are considered for the past, present, and future
population scenarios?
Answer:
For MASTER-2005, future epochs did not include the option to simulate below 1 mm. This has been changed for MASTER-2009.
The entire population between 1957 and 2060 includes objects down to 1 micrometer in size.
Question:
What time steps are used for debris populations snapshots for the past, present, and future population scenarios?
Answer:
For epochs from 1957 until 2009 (May) population snapshots are provided at 3 month intervals. For epochs from 2009 (June
to 2055 population snapshots are provided in 1 year intervals, centred on May 1 of each year.
Question:
Do the resulting fluxes for a specified analysis time interval give the mean flux levels, or a flux level
at a particular instant (e.g. at the beginning, center, or end of the interval)?
Answer:
The given fluxes provide mean levels, averaged by integration over piecewise constant flux conditions
(around snapshot epochs), for the analysis time span, in such a way that the fluence = (mean flux) x
(total time span), is correctly represented.
Question:
What is the difference between Global flux and Total flux in the MASTER output files?
Answer:
Total flux only refers to the respective spectrum and the chosen parameter range of that spectrum. Global
flux is the overall flux calculated by MASTER.
Question:
When will the online version of MASTER be available and how will this work?
Answer:
The online version will be included after the website has been migrated to an ESA server. The Graphical
User Interface may then be launched from this site via Java Web Start. The user settings will be sent over the internet to
ESA's server where MASTER will be executed. The results will then be sent back to the user to be viewed in the GUI.