This Digi Kit was developed to promote understanding of planetary magnetic fields and how to interpret magnetic field vectors. The keystone of this Kit is the Guided-Inquiry Lab by the NASA Space Science Education Consortium, which tasks students to build physical models to mimic an Earth-like magnetic field and a Planet X (similar to Mars) which has only the remnants of a long-defunct magnetic field. A smartphone sensor app is then introduced to map field vectors on each of the highly different model "planets". The digital resources linked in this Digi Kit provide robust background on the magnetic fields of planets in our own solar system, interactive activities to investigate Mars' strange crustal magnetism, and news about how astrophysicists hope to tease out magnetic field data from exoplanets. A key takeaway is that without a magnetic field, it's doubtful that life could be sustained on a planetary surface. Even if we develop technology to transport humans to Mars, the red planet would have to be greatly transformed. Teachers: this resource addresses explicit content standards related to Earth's magnetic field and why it is essential to human life (Earth's magnetic field deflects ionizing radiation from the solar wind and high energy cosmic particles such as protons and heavy ions from outside our system).