BayernSat takes pictures of the Earth and sends them via a relay satellite
to the Earth, where they are published in television and on the Internet.
Internet users are allowed to remote control the cameras of BayernSat.
BayernSat is a small satellite mission of the Institute of Astronautics of
the Technische Universität München. The goal of the mission is to
demonstrate new technologies, especially telepresence.
Rationale
In lower Earth orbits the communication windows are typically strongly
limited. The ground station is only visible for a few minutes per overflight,
and that occurs only a few times per day on average. Hence, the download
of mission data has to take place in this short time slot. This however
results in stringent requirements for the communication system (increased
data rate) and the power subsystem (increased peak power usage). For missions
that require extended communication windows or realtime data transmission,
this is unacceptable. The solution is here the utilisation of geostationary
satellites (as done by e.g. Spot 4, EnviSat). The advantage is that the
com window can be extended from a few minutes to approximately half the
orbit period (some 45 minutes) and more. In more than half of the cases
the satellite can be reached immediately. When more than one geostationary
satellite is used, the coverage can be - in principle - increased to 100%.
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Telepresence
BayernSat goes even one step further. The communication windows are not
only enlarged time wise, but are also to be utilised to enable telepresence
in orbit. In astronautics, there are several applications for this. Stranded
satellites can be repaired or fuelled. Docking manoeuvres can be simplified
significantly; many applications can be undertaken - instead of by astronauts
in space - from robot-controllers on the ground (and hence much cheaper).
This however requires telepresence in orbit. Demonstrating the feasibility
of this technology is the aim of BayernSat.
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Further Technologies
Apart form telepresence, there are a couple of other technologies that
are to prove their usability. There are for example the most efficient solar
cells that have ever been flown on a satellite (Penta-Junction, 34% efficiency),
on-board high performance computing using a silicon-on-insulator computer,
and a parallel processor architecture (XPP), a high-resolution colour video
camera, as well as a number of low-cost systems that will feature comparable
performances at a much lower price.

Public Outreach
Even with its high-level technical challenge, BayernSat should not be appealing
to just a small group of space experts. The aim is to demonstrate the
above-mentioned technologies in a way that fascinates the broad public,
namely by interactive
live images of Planet Earth as it is "now". The BayernSat satellite
shall, whenever illumination and com windows allow, transmit a live feed
of Earth remote sensing data to the ground station at the Institute of
Astronautics. But apart from that, this stream of images shall be put
online in the Internet
to be accessed by the public. The Bavarian TV broadcaster "Bayerischer
Rundfunk" has offered to also show the live video feed in its telecast "SpaceNight".
Furthermore, randomly selected Internet users shall be allowed to take
control of the camera via their keyboard at home, and see the resulting
changes
within short time on the Internet / on TV. This approach aims at making
BayernSat appealing to a broad public without losing the opportunity
to undertake the needed technology tests. The ultimate goal is the development
of a telepresence module, which allows other space missions to utilise telepresence.

BayernSat team
The Satellite
BayernSat is basically a cube with a side length of little more than 40cm
and a mass of 50kg. It can transmit data at least ten times faster than
a computer modem. Furthermore, it is able to communicate with geostationary
communication satellites as well as transmitters and receivers on the ground.
The ground resolution of its video camera is better than 150 metres
Short
Description BayernSat
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