2021-10-06, 06:48 PM
I subscribed to ESA's NEO Coordination Centre | Planetary Defence Office (this must be the coolest employer name to put on LinkedIn for those people) and there is an interesting note in their October issue: "of the almost 27 000 discovered NEOs, about 25% have an observed arc of less than a week, and 50% have been seen for less than a month. Many of these objects will likely be already unrecoverable at their next favourable apparition, and will have to be rediscovered in the future."