They are missionaries for The Navigators, which is a ministry that shares the gospel of Jesus and helps people grow in their relationship with Him through discipleship. To share the gospel and disciple all people in all places, The Navigators includes a wide variety of ministries and a broad family of missionaries, supporters, and volunteers. The Navigators reaches and disciples people in need of the gospel where they work, live, worship, and play: on college campuses and military bases, in inner cities, workplaces, churches, and local communities, and in hard to reach places.
Here is their website if you would like more information: Navigators website (click here).
And here is a 5-minute introduction video of Mitsuna’s ministry to give you clearer picture of what they are doing. I hope you will take the time to watch it. Video (click here).