🧠 The Daily Fact #13

In the 1960s, NASA engineers invented a pen that could write in zero gravity, costing about $2 million to develop. Unlike a regular pen that relies on gravity to pull ink down, this "space pen" used pressurized ink cartridges, so it could write upside down, underwater, and even in extreme temperatures. Ironically, the Soviet cosmonauts used a simpler solution—they brought pencils.