The place to start to answer this question is with Phenomenology. Phenomenology was first created by Charles Peirce and then separately by Edmund Husserl. It is the study of what actually goes on within our consciousness without reference to external unknowables which are all bracketed out. If we start with Husserl’s idea then the root of consciousness is the intentional morphe (form), which organizes the hyle (content), which basically says that a transcendental synthesis of content by form occurs. Husserl is extending the viewpoint of Kant here that there are a priori projections upon external noumena. Noumena are the unknowables that are external to consciousness. But then Husserl goes on to differentiate Noesis and Noema. These are combinations of form and content, where Noesis is more form and noema are more content. Husserl says that form and content are never separate in consciousness. Now Husserl also assumes that the imposition of form on content is at the same time the projection of meaning. Thus noesis is not just imposing a form on content but also finding meaning in that projection. Husserl goes on to say that objects in consciousness are noematic nuclei which are constituted from every angle of approach by horizons of exploration, and real objects have almost infinite horizons of exploration, mere phenomena of consciousness itself phenomena like memories or imagination have more limited horizons of exploration. And most importantly he differentiates the external coherence of the noematic nucleus of the object from the internal coherence which is its whatness which is normally thought of as a set of constraints on its attributes. This is all so Husserl can differentiate between Ideas which are abstract glosses from Essences which are directly intuitable understandings of the nature of the object. Thus for the first time essences are distinguished from ideas and are not seen as merely simple ideas as Descartes thought. This distinction later is turned by Heidegger into the difference of modalities for Dasein’s being-in-the-world between present-at-hand which is abstract presentation of phenomena as objects to a subject (Pure Being) and ready-to-hand which is circumspective concern with regard to the totality that occurs in our relation to the technology that underlies our orientation (affordances) to and manipulation of to things, i.e. our behavior toward things as a whole within the world (Process Being).
With this background you can see that Husserl is assuming that everything in consciousness is consciousness of something, i.e. a constituted intention with regard to a specific thing. Later Aron Gurwitsch comes along and adds gestalts to phenomenolgy and talks about fringe phenomena that are not fully intentional. And it is here that we start to get an understanding of the difference between awareness and consciousness. Awareness is a general background to consciousness, and might be seen as relating to Existence rather than Being. In fact this is part of the reason that Heidegger talks about Dasein which is prior to the differentiation of the subject and object. Dasein can go into a mode of being-in-the-world which has circumspective concern and is not directly intentional projection. For Heidegger both the present-at-hand and ready-to-hand modes are kinds of Being. And Existence is what is found that is prior to either of these projections of abstract glosses where intentions project forms on raw matter of consciousness, or of circumspective concern on the totality of relations between technological and behavioral underpinnings our actions in the world.
But awareness of existence are left out of all these accounts. The idea that there is no intentional morphe being projected on things, or that there is no ecstasy of dasein by which it projects the world within which it has its being is not considered. Awareness of existence relates merely to what is found prior to any projections on it. And the question is whether we have access to that. My answer to that would be yes. There is beyond all the modalities of Being a direct access to Existence and that is what you can get to through meditation of various forms, or when you are just taking in what is before you without having any vested interests in projecting value upon it, or taking any sort of orientation to it behaviorally that is the hallmark of circumspective concern. Existence is the rock beside the road that no one cares about, which is just found there left where it is. When we look at things that are just found before us, and are not part of our life project in any way, then we are looking at existence, and this is what I think awareness is. Part of what makes meditation what it is is that we are giving up both the projection of intentionality onto things, but also behavior toward the things that signifies our circumspective concern for the interoperability of the totality.
Now that we have disentangled awareness from consciousness, and seen that there is an intermediate case of circumspective concern we can move back toward answering the question. We went into all this philosophical history from phenomenology because you said you wanted to know the exact relation between awareness, consciousness and memory. Consciousness is defined in Phenomenaology as intentional constitution of objects and these objects are as Merleau-Ponty says pointed at and rendered present-at-hand. Then there is an infrastructure of behavioral practices toward things normally that is hidden unless something breaks down, which is circumspective concern where we discover the essences of things through their actual manipulation within our world which Merleau-Ponty says is related to grasping of things as ready-to-hand as an interoperating totality of things within the world. But when we meditate we cease our behavioral manipulation of things, and we cease the constitution of objects intentionally. And what we find then is awareness without the active projection upon it of anything and what is unleashed in that is myriad phenomena of awareness itself like the activation of memories, imagination, stray thoughts, where the mind works overtime to fill the space created by our attempts to cease to projecting either intentionally or in terms of behavior toward things.
What happens when you meditate at deeper and deeper levels of awareness is recorded in the various Buddhist sutras in which the Buddha finds more and more interesting things to say about what is the goal of the process of enlightenment as described by the various schools of Buddhism. Buddhism is directed at the uncovering of empty existence beneath the projections of illusions of Being. But you don’t have to meditate to reach awareness, it is always there as the bedrock of our consciousness. The key point is that awareness is inherently reflexive or reflective. We are aware that we are aware in the act of awareness itself. Meditation is accessing this reflexive nature of awareness, because when you are not doing anything else but looking at your own consciousness and its shenanigans then you become poignantly aware of your awareness.
Now this explanation would not be complete without mentioning the Unconscious. Note that the Personal Unconscious of Freud, or the more basic Collective Unconscious of Jung are both related directly to consciousness as its inverse. Consciousness is seen as being like the tip of the iceberg much of which is beneath the waters where its workings are not accessible. And this has to be true because we are presented in consciousness with a priori synthesis within experience and something has to be doing all that synthetic work. So in a way the idea of the unconscious merely goes back to Kant’s assertion that we are immersed in a prior synthesis, and it is merely asking where that synthesis comes from because we are not conscious of creating those syntheses that appear within our experience. The key point here is that much of what we are unconscious of is available to awareness. And that is why there are all kinds of Psychtherapy of the Gestalt type that ask you to be aware of what is around you, and by doing that many times things that you are not conscious of bubble up to the surface of awareness and are resolved at least partially.
But the question becomes, is there anything we are not aware of. It seems that as we explore awareness of empty existence we get deeper and deeper and our awareness continues to expand until we feel as if we are aware of everything. This is because the basis of reflectivity is the interpenetration of things and that interpenetration that is intrinsic to the constitution of things makes it seem as if we were connected to everything that exists. And we now know from the fact that there was a big bang and through Bells theorem that everything in the universe is entangled and in fact we are physically connected at the quantum level with everything else at some level.
Now in all this we have not touched very much on memory. And that is because it would mean we would have to take into account time, and our intrinsic relation to time. For Husserl there was only linear time and the relation to memory was one of the fading of the traces of the now. See the famous diagram in Internal Time Consciousness which was edited by Heidegger. Heidegger himself in Being and Time said that the moments of time, present, past and future were equi-primordial meaning that we are actually immersed in all the moments of time simultaneously. Dogen Kaigen talks about Existence-Time which is how time looks from the point of view of Soto Zen practice which is again different from what Heidegger thought about time. In general, Time and Existence are the same thing with respect to Buddhism because it sees only aggregates in flux. But the flux itself does not arise nor does it cease. Memories, Imaginations, Dreams, Hopes are all part of this flux in a marvelous and mysterious mixture which is different for each of us, and continually different from itself through the production of unending variety.
So I hope this helps put into perspective the relations between awareness, consciousness, and memory as it is seen in phenomenology and how that phenomenology gives us access to understanding the nature of Buddhism as a way of getting back to Existence from the projections on it of Being. Getting to awareness can be done by meditation, or just a moments reflection, when you stop and look around you and wonder where you are going and what you are doing, and why you are here now with the emphasis on sensing the world around you in the present and how you are feeling and what sensations you are having at the moment within your body.