The present work analyses the requirements related to the orbit and the effects
of the space radiation on Polosat, a toy-model satellite whose main goal is to
monitor and image the Earth Poles. Our main objective has been to work on
the so-called phase A of the design of a space mission, in which a preliminary
study of the viability and characteristics of the mission is made.
We present this project as a coordinated work due to the fact that its
competition required the use of two relatively complex software tools, as well as
the achievement of extra theoretical background on orbital mechanics, radiation
and its effects. One of the software tools was STK (Satellite Tool Kit). It allows
to compute with realism and high degree of accuracy the time evolution of the
kinematics of an object in orbit around the Earth. The other tool was SPENVIS
(Space Environment Information System). It also computes the time evolution
of the orbital parameters of an object -although with less option for realism and
accuracy than STK, and the characteristics of the incident radiation and its
effects of the orbiting object. Both software tools are used in professional and
academic environments and, therefore, becoming familiar with them and their
use has been an important and useful part of our work.
We compare the results that STK and SPENVIS yield for the computation of
the orbital kinematics in the cases where both tools are appropriate (cases with
negligible atmospheric drag and limited intervals of time). We check that in
such cases STK and SPENVIS results yield a very good agreement and, most
importantly, we have found the procedure in which results from STK can be
transferred to SPENVIS, in order to model the situations we are interested in.
As we show, by using both codes, we can take advantage of both the powerful
numerical tools of STK in order to study orbital mechanics, and the capabilities
of SPENVIS in order to model the incidence of radiation and its effects on the
spacecraft.
Finally, we have concluded that both STK and SPENVIS are convenient tools
for developing the proposed project and have determined the way in which we
can use them in order to accomplish our objectives.
