The phrase "unique constellation" means a special, one-of-a-kind combination of things or elements that come together in a specific way. Full definition
Clegg left himself open to accusations of «talking down the economy» by comparing Britain's «unique constellation of vulnerabilities» to those of Iceland. (politics.co.uk)
«I think when it comes to the banking system, people are living in denial about quite how vulnerable we are as an economy,» he warned, describing Britain's economy as being placed in a «unique constellation of vulnerabilities». (politics.co.uk)
The result is that each act of preaching takes place within a unique constellation of contexts and that the more that constellation changes the more will the meaning of the sermon itself change, even if it is repeated verbatim. (religion-online.org)