From physics standpoint, yes.
But as I've repeatedly mentioned, Life Fibers explicitly in-universe don't care about physics. If Ragyo ripping Ryuko's heart out with her bare hands didn't do any permanent damage, I doubt that Shadow could kill her that way.
Even then... I'm not so sure. We're talking Gurren Lagann levels of "I'm too awesome for physics to matter" here. After the last episode, throwing her into the sun might just piss her off. And with Senketsu she can fly and survive unaided in space, so...