The power of Astral Projection allows the psychic to split his spirit off from his body. The discarnate spirit can travel very quickly in this form. The spirit intangibly travels across planes of thought (the Umbra) while still able to look in on the physical world (through the Gauntlet). While in astral form, the psychic cannot at first physically affect the real world, though he may use other psychic abilities (the difficulty numbers for doing so are increased by two). However, while away from his body, he cannot perceive what is happening to it. Many out-of-body travelers have nightmares about someone moving or harming their physical self while their spirit is roaming free.
Two astrally projecting characters may affect each other (or other spirits), though for purposes of astral combat, they substitute their Wits for Dexterity, their Intelligence for Strength and their Perception for Stamina. Most astral spirits appear as blurry forms, barely in the realm of perception. In general, while an astral spirit can see the material world or other abstract spirits in the Umbra, ghosts of the dead and the like usually remain imperceptible except to those psychics who also have some mediumship abilities.
To release the astral form, the player spends one point of Willpower and rolls for the power. Successes beyond the first lead to temporary dots of stamina for purposes of time spent out-of-body, and soaking damage upon return. Should the player botch while attempting to have his character step outside his body, the psychic is unable to leave his body for 24 hours. Psychics who frequent the astral plane whisper that other entities sometimes intrude there, human or otherwise, and on some occasions find their souls drawn to strange spirit worlds far removed from the mortal plane. A few never find their way back. Caution is the rule when exploring planes unknown to humans.
The psychic’s spirit is connected to their body via a sort of spiritual connection or tether. This connection is nigh invisible, but can be sensed by those with appropriate abilities (ex/ higher Sensitivity score, Auspex, or Spirit sphere). Should this break, it becomes very difficult for the spirit to return to the body without outside aid. This tether can also be dangerous in that it could possibly lead others to where the body remains sleeping. Possession of the body is also easier when the spirit is projected. As long as the tether remains, however, the psychic can snap instantaneously back to their body, but not without mental repercussions: A psychic takes mental damage equivalent to 7 bashing (soaked normally) for this speedy return; if none of this damage is soaked, they are knocked unconscious. This damage heals as normal for bashing.
If a spirit takes damage (almost always aggravated), that damage is translated to lethal when they return to their body. If they return to their body with the instantaneous snap mentioned above, what damage they have stacks with the mentioned 7 bashing, and must be resoaked by the physical body. If more than 7 damage is taken in total, the physical body enters a coma until all lethal damage done in this way is healed (as normal, or through mystical means).
If the spirit is killed within the Umbra, the body will die soon after. The other danger connected with this power is the possibility of addiction to the Umbra and out of body experience, which could lead to the spirit not wanting to return to the body. Should the body die, the spirit does not automatically die, but it is stuck within the Umbra (unless a new body is found).
When the psychic's time runs out, they are immediately shunted back to their bodies and take the associated damage. A psychic is always aware of how much time they have left.
Roll: Perception + Meditation (difficulty 8)
• With only rudimentary awareness of astral existence, the psychic can shift her senses to feel the astral realm but cannot quite enter it. The psychic sees the astral realm (Penumbra) overlaid upon the normal physical world. Some psychics prefer to close their eyes and visualize the astral plane, while others have no difficulty watching both. A psychic may view the astral realm for so long as she maintains her concentration upon it. The psychic is thus considered as existing in both the astral and physical realms, though stationary, and is vulnerable to attack (though they may defend themselves).
•• The character can leave her body for one minute per point of Stamina (Willpower may be spent for extra minutes on a one-for-one basis). She is limited to traveling approximately one mile away from her body.
••• The character can leave her body for up to 10 minutes per point of Stamina (Willpower may be spent for an extra ten minutes per point spent). She can travel up to 100 miles from her body. Additionally, the psychic may manipulate or move small, light objects with a successful Willpower roll.
•••• The psychic can now leave her body for up to an hour per point of Stamina and travel up to 1,000 miles away (Willpower may be spent for one extra hour per point). If the player succeeds on a Charisma + Occult roll (diff 8), the psychic can manifest visually to observes as a translucent, ghostly apparition, though the projector can only communicate in the most basic of ways with observers (like ghosts). They may now move medium objects of a slightly heavier weight (but not too heavy).
••••• The psychic may astrally travel anywhere in the world, so long as her body remains healthy. The psychic's form (should she choose to manifest, using the same roll previously noted) appears as a blurry and translucent version of her usual physical appearance, somewhat idealized. While manifest, the projector can speak intelligently, though only in a soft whisper. Like her visual appearance, her speech does not appear on recordings. The psychic may now move large objects of moderate weight (like a desk).
Source: Homebrew/Sorcerer Revised Version