Mission Design for the CubeSat OUFTI-1

CHAPTER 5To conclude, we can say that with a footprint’s length of 3128 Km, OUFTI-1can cover the entire western Europe at once. Anyway, also at 350 Km altitudewith a footprint’s length of 1580 Km, the satellite passing over Paris can keep incontact an amateur radio operator in Lisbon with one in Stockholm. Concerningthe Area Coverage Rate, it depends on the instrument dwell time and for anomnidirectional antenna it hasn’t any meaning.The Area Access Rate is estimated through the following formula:AAR = 1.49 · 108 sin (λ)T5.6 Communication time={11660 Km2s6073 Km2s(1200Km)(350Km)(5.25)Directly connected to the earth coverage, we need to consider the communicationtime with the ground station in Liège. In fact, this is one of the drivingrequirements for the OUFTI-1 design. We are dealing with an amateur radiosatellite: as the community of amateur radio in almost uniformly distributedall around the world, we chose to favor the Belgian amateur radio operators.In this way we also maximize the time available for communication with ourground station in Liège.But the same problem reappears in this case too: we cannot impose the orbitalparameters and specifically the argument of perigee and the right ascension onascending node. Hence we can only analyze the best and the worst situationand verify if the time is enough to satisfy the mission requirements.The worst case is represented in figure 5.6: as the perigee is over Belgium, thespeed of OUFTI-1 passing over the ground station is extremely high and thetime consequently really short.In the worst case we have an access time of 30 min/day. It seems to besufficient but this time is not continuous: the maximum continuous access timein the worst case is about 8 minutes.The best case is instead when the apogee is over Belgium and its representedin figure 5.6: in this case the time available for communication is much higheras the satellite is passing slowly over the ground station.In the best case we have an access time of 104 min/day with a maximumcontinuous time of 17 minutes.Galli Stefania 52 University of Liège