Originally Posted by Hunter Rider
Nat pulls the rubble dirt covered look off so well!
I think it's a device for opening the portals as well, I've seen the idea that she has been testing it to get back to Thor and I can see that leading to her opening the wrong portal, it will probably also link into the portal that opened in The Avengers.
Targeting would be a real technical challenge. She may have some idea of in what direction Asgard lies from her measurements in Thor1 and any measurements she's able to take when Thor and Loki depart at the end of The Avengers (seems likely she would). But if she is off by even 0.0001%, at that distance, it could be a huge error.
Now, the error I describe doesn't necessarily fit with Norse Cosmology (Asgard is supposed to be "above" us and Svartalfheim "beneath" us). But yeah, they could do something like that. It would certainly be interesting!
The portal in The Avengers was opened with the Tesseract. Since the Tesseract went to Asgard at the end of TA, I'm not certain how Jane & Co. could tap it.