Astronomy, Doughnuts, and Carrying Capacity

TL;DR

This paper critically examines ecological concepts in space environmentalism, proposing that tracking the number of Anthropogenic Space Objects is a practical metric for assessing space environment damage.

Contribution

It introduces the idea of using the number of space objects as a key metric, moving beyond ambiguous ecological terms, and suggests adopting a Planetary Boundaries approach for space.

Findings

Number of space objects is a crucial metric.

Reflectivity of objects doubles every 1.7 years.

Sky overcrowding affects astronomers and satellite operators.

Abstract

I examine the applicability of ecological concepts in discussing issues related to space environmentalism. Terms such as "ecosystem"", "carrying capacity"", and "tipping point" are either ambiguous or well defined but not applicable to orbital space and its contents; using such terms uncritically may cause more confusion than enlightenment. On the other hand, it may well be fruitful to adopt the approach of the Planetary Boundaries Framework, defining trackable metrics that capture the damage to the space environment. I argue that the key metric is simply the number of Anthropogenic Space Objects (ASOs), rather than for example their reflectivity, which is currently doubling every 1.7 years; we are heading towards degree scale separation. Overcrowding of the sky is a problem astronomers and satellite operators have in common.