  Since the 2000's, an increased number of nanosatellites have accessed space.
However, studies show that the number of unsuccessful nanosatellite missions is
very expressive. Moreover, these statistics are correlated to poor verification
and validation processes used by hobbyists satellite developers because major
space agencies keep high successful ratings even with small/nano satellites
missions due to its rigorous V\&V processes. Aiming to improve payloads
integration testing of NanosatC-BR-2, a 2-U Cubesat based nanosatellite under
development by INPE, the fault injection technique has been used. It is very
useful technique to test systems prototypes. We present the design and
implementation of a Failure Emulator Mechanism (FEM) on I2C communication bus
for testing the interaction among the NCBR2 subsystems, supporting
interoperability and robustness requirements verification. The FEM is modelled
to work at the communication bus emulating eventual faults of the communicating
subsystems in the messages exchanged. Using an Arduino board for the FEM and NI
LabView environment it is possible to program the mechanism to inject different
faults at the I2C bus during different operation modes. Based on a serial
architecture, the FEM will be able to intercept all messages and implement
different faults as service and timing faults. The FEM interface with the
tester is designed in LabView environment. Control and observation facilities
are available to generate and upload the faultload script to FEM Arduino board.
The proposed FEM architecture and its implementation are validated using two
subsystems under testing prototypes: the OnBoard Data Handling Computer and the
Langmuir Probe NCBR2 payload. For this analysis purpose, the prototypes
simulate in two different Arduinos boards the expected behavior of each
subsystem in the communication.
