There is no substitute for the Space Pen (I personally use the bullet style pocket size). It uses a pressurized gasket to push the ink in any position so will

There is no substitute for the Space Pen (I personally use the bullet style pocket size). It uses a pressurized gasket to push the ink in any position so will writ upside down all day long. It has a great backstory as being an unsolicited proposal to NASA to write in zero gravity [1]. The very best pen gift for any Engineer. [1] https://www.scientificamerican.com/article/fact-or-fiction-nasa-spen/ https://www.scientificamerican.com/article/fact-or-fiction-n...