Satellites: Tough old birds

ON EARTH it is a fact of public life that politicians love to trumpet new infrastructure but take much less interest in maintaining what already exists. The same rule, it appears, applies in outer space. Many satellites launched for important purposes such as monitoring solar weather (bad solar storms can damage electrical equipment on Earth), tracking the climate and just helping people navigate are limping along in need of replacement. One that is about to be substituted is the Advanced Compos...