I've been thinking for some time on the interactions of the Astral Projection spell with some other spells (ones that can ruin a PC's day, like Flesh to Stone, Imprisonment, Temporal Stasis, and Trap the Soul).
Some nice discussion of these interactions can be found here and here.
One suggestion I noted in the first discussion was:
You could dispel magic the caster's real body to end the spell. Consider it as part of your comprehensive backup plan.
I do assume you have a couple of simulacrum and possibly a golem or two guarding your body with instructions on how to react in various situations.
So, say you've gone adventuring after using astral projection and made your physical copy on some non-Astral plane. Now some sorry mage manages to hit your with one of the annoying spells previously mentioned and it takes affect (you failed the saving throw and your SR was beat). If you could get someone to successfully dispel your astral projection on your original body, would that save you from Flesh to Stone/Trap the Soul/Imprisonment/Temporal Stasis?
Flesh to Stone: Yes
Trap the Soul: No
Imprisonment: Signs point to yes
Temporal Statis: Yes
Flesh to Stone: Yes
Trap the Soul: No
Imprisonment: Signs point to yes
Temporal Statis: Yes
Thank you for the succinct answer.
Of course, it would be nice to have some security against soul trapping...so I found this: Iron Circlet of Guarded Souls
Suppose, you've got one of these fancy circlets. If you cast Astral Projection (say with the circlet in your bag of holding/handy haversack), then manifest a physical body on some non-Astral plane, you'll have a copy of the circlet with you (just like all your other gear, per astral projection).
Now, if you put on the circlet after you're using a new body from Astral Projection...what do you suppose happens?
To me it seems like you might be fine (if you can Trap the Soul on people under the effect of Astral Projection, surely their souls are present in the copied body). But, say your copy is killed while wearing the circlet...well, it disappears like your other gear (and your body) per Astral Projection and you wake up in your real body. Does that sound about right?
If you could get someone to successfully dispel your astral projection on your original body, would that save you from Flesh to Stone/Trap the Soul/Imprisonment/Temporal Stasis?
I would say that give the fact that your mind/soul are in the new body, you would have different effects:
Flesh to Stone: Dispel on the original body allows the astral traveler to return, unharmed to his old body.
Trap the Soul: No change, soul is trapped just as if it were cast on the original body.
Imprisonment/Temporal Stasis: Dispel on the original body allows the astral traveler to return, unharmed, to his old body.
My reasoning is this: affecting the astral body with some debilitating effect does not prevent the soul from returning to the original body. Ergo, spells that effect only the body are pretty much useless for this purpose.
However, spells that impact the soul go with the soul regardless of which body it occupies.
The only difference, really between astral projection and possession is astral projection creates a new body, whereas possession has to inhabit one that already exists.