How is the Mass missionary? I defer to Pope Benedict XVI:
After the blessing, the deacon or the priest dismisses the people with the words: Ite, missa est. These words help us to grasp the relationship between the Mass just celebrated and the mission of Christians in the world. In antiquity, missa simply meant "dismissal." However in Christian usage it gradually took on a deeper meaning. The word "dismissal" has come to imply a "mission." These few words succinctly express the missionary nature of the Church. The People of God might be helped to understand more clearly this essential dimension of the Church's life, taking the dismissal as a starting-point. (Sacramentum Caritatis, n. 51)To understand the missionary layer of the Mass, one has to consider the Mass as a communion between God and man. The Mass is full of giving and receiving and "coming near to". We begin Mass "going in to the altar of God" (even if those words are not present in Ordinary Form of the Mass) in the entrance procession; we come near to God. In the Liturgy of the Word, God comes to us in His Word. Then the priest offers our bread and wine to God, who returns them to us as the Body and Blood of His Son. Then the priest offers Jesus Christ, the Divine victim, the Eucharist, to the Father; and God, through the hands of His priests (ideally...), offers Himself to us in Holy Communion. At the end of Mass, the priest gives us God's blessing, and says (ideally...) Ite, missa est! We are sent on a mission. What are we sent with? The Word of God (which we received in the Scripture), the Eucharist (which we received in Holy Communion), and God's blessing. That is sufficient for any mission.
I can see the Mass as being a portrayal of Holy Week (and beyond), encapsulating Jesus' triumphant entry into Jerusalem through the Passion and all the way to the Ascension.
Anyone care to chime in on the spiritual and didactic layers of the Mass?