  Over the last decades, space has grown from a purely scientific struggle,
fueled by the desire to demonstrate superiority of one regime over the other,
to an anchor point of the economies of essentially all developed countries.
Many businesses depend crucially on satellite communication or data
acquisition, not only for defense purposes, but increasingly also for
day-to-day applications. However, although so far space faring nations
refrained from extending their earth-bound conflicts into space, this critical
infrastructure is not as invulnerable as common knowledge suggests. In this
paper, we analyze the threats space vehicles are exposed to and what must
change to mitigate them. In particular, we shall focus on cyber threats, which
may well be mounted by small countries and terrorist organizations, whose
incentives do not necessarily include sustainability of the space domain and
who may not be susceptible to the threat of mutual retaliation on the ground.
We survey incidents, highlight threats and raise awareness from general
preparedness for accidental faults, which is already widely spread within the
space community, to preparedness and tolerance of both accidental and malicious
faults (such as targeted attacks by cyber terrorists and nation-state hackers).
