Thanks.
The omission from the wiki instructions (which I found on "Game Slowdown" page) is that, if we aren't playing with SM mode on from the start, we must reopen the System Map window in order for the relevant button to display, which is inconsistent from, say, the grayed-out buttons on other interface screens like "unlock design" in the Class Design window. It isn't enough to open SM mode and click on the Contacts tab as the wiki instructs.
I did search the forums, btw (as I have before all "how to" questions thus far). "Spacetime bubble" (the spelling from the wiki page) did not return the results of "space-time bubble" maybe?