  Sensitive computation often has to be performed in a trusted execution
environment (TEE), which, in turn, requires tamper-proof hardware. If the
computational fabric can be tampered with, we may no longer be able to trust
the correctness of the computation. We study the idea of using computational
platforms in space as a means to protect data from adversarial physical access.
In this paper, we propose SpaceTEE - a practical implementation of this
approach using low-cost nano-satellites called CubeSats. We study the
constraints of such a platform, the cost of deployment, and discuss possible
applications under those constraints. As a case study, we design a hardware
security module solution (called SpaceHSM) and describe how it can be used to
implement a root-of-trust for a certi cate authority (CA).
