Perpetual motion refers to a hypothetical concept of a motion that continues indefinitely without the need for an external source of energy. According to the laws of thermodynamics, specifically the first and second laws, perpetual motion machines of the first kind (machines that produce work without any energy input) and perpetual motion machines of the second kind (machines that transfer heat from a cooler body to a hotter body without any work input) are not possible.
In the context of space, the laws of thermodynamics still apply. Therefore, perpetual motion machines as traditionally conceived are not possible, whether in space or on Earth. The conservation of energy and the principles of thermodynamics remain fundamental principles of physics regardless of the location.
However, it's worth noting that space offers unique conditions and possibilities that can be exploited for certain types of long-term or continuous motion. For example, spacecraft can utilize solar panels to harness solar energy and generate electricity to power their systems and propulsion. This allows for continuous motion as long as the energy source (the Sun in this case) remains available.
While space provides certain advantages, such as the absence of atmospheric drag, perpetual motion as commonly understood is still not achievable due to the fundamental laws of physics.