ElDee

It was moved slightly, you can find it on the wall near the tunnel.

Head behind the big building in Ouroboros. You'll find another portal that'll get you to all the Echo zones.

The Constant is an Accolade for collecting every exploration badge in both Atlas Park and Echo: Atlas Park. Also, the Condemned badge eluded me for literally hours of searching over the weekend. I must have landed on every single surface in the zone except the one with the badge on it. Thank you!