Physics and Star Wars
To estimate the effects of the second Death Star, Minton looks into its mass. According to estimated data from some students of Lehigh University, the steel mass needed for building one would be around 770 kilograms times the mass cubed in weight. This would give the Death Star of about ten to the power of nineteen kilograms in mass. Using this data, Minton produces equations that lead him to conclude the fragments would hit the moons surface so hard causing craters almost four times the size of the Chicxulub crater in Mexico. This impact would cause a planetary firestorm and vaporize all lifeforms on the moon.
Death Star
The anthology film "Rogue One" focuses on a band of Rebels stealing the plans for the first Death Star prior to the events of "A New Hope". The Death Star project was overseen by Orson Krennic, the Director of Advanced Weapons Research for the Imperial Military. Under Krennic's supervision, the project was beset by constant delays, and he forcibly recruited weapons designer Galen Erso (the father of Jyn Erso, the movie's main protagonist) to complete the design; nevertheless, it was another fifteen years before the Death Star was operational. The Death Star's primary laser was powered by kyber crystals mined from the desert moon of Jedha, and is first used to destroy Jedha City both as a response to a violent insurgency on the planet, and as a display of the Death Star's operational status to restore the Empire's confidence in the project. Grand Moff Tarkin assumes control over the Death Star while Krennic investigates security breaches in the design project. It is subsequently revealed that Galen discreetly sabotaged the design by building a vulnerability into the reactor. This is the same vulnerability that Luke Skywalker takes advantage of during the events of "A New Hope". After the Death Star plans are stolen from the Scarif vault, Tarkin fires the Death Star laser on the base killing Krennic, as well as Jyn Erso and Cassian Andor.