Josh Finch, a NASA spokesperson, tells Spaceflight Now that the agency's calculated "Loss Of Crew" probability for SpaceX's Demo-2 test flight is 1-in-276, exceeding the commercial crew program's requirement threshold of 1-in-270.
In response to a question from Spaceflight Now, Finch said the 1-in-276 number includes mitigations to reduce the risk, such as on-orbit inspections of the Crew Dragon spacecraft once it's docked at the space station to look for damage from micrometeoroids and orbital debris, or MMOD.
Collisions with tiny fragments of space junk or naturally-occurring dust grains or pebble-sized rock fragments could damage the ship's heat shield.
NASA pegs the overall risk of a Loss Of Mission is 1-in-60. That risk covers scenarios where the Crew Dragon doesn't reach the space station as planned, but the crew safely returns to Earth.