Understanding the freezing weather sweeping across the United States — and why Texas’s independent power grid was doomed to fail in its wake. Plus, NASA tries to land a car on Mars.

The rise and fall of Philly’s mass vaccination clinic

Post Reports is the daily podcast from The Washington Post. Unparalleled reporting. Expert insight. Clear analysis. Everything you’ve come to expect from the newsroom of The Post, for your ears. Martine Powers and Elahe Izadi are your hosts, asking the questions you didn’t know you wanted answered. Published weekdays around 5 p.m. Eastern time.