Stasis

"The Children's Hour."

I am struggling with some technicalities.

Captain Jonah Matthieson and Lieutenant Ingrid Raines will travel in Matthieson's Dart-class attack boat, the United Nations Space Navy Catskinner (large fusion-power unit; small life-support bubble; deep-space sensors and weapons) which will be carried on an experimental ramscoop ship, the Yamamoto, which in turn will accelerate from Sol to Alpha Centauri where it will pass through that kzinti-held planetary system while launching missiles at kzinti installations;

the Catskinner, leaving the Yamamoto while enclosed in a stasis field, will be slowed to an orbital speed by friction with the outer layers of Alpha Centauri;

Jonah admits to being scared:

"'...because we will start this mission utterly dependent on the intervention of outside forces; the offswitch is exterior to the surface of the effect.' It had to be; time did not pass inside a stasis field."
-Chapter I, p. 168.

Will they be dependent on someone finding the stasis field and switching it off or is the switch pre-timed to turn itself off after a specified period? If the latter, then why does Jonah say that they will be dependent on intervention by external forces?

There will be more about this but I am being interrupted here.

Addendum: This post contains an error which will be corrected in the next post.