Bezos' rocket achieves controlled landing back on Earth NOV 24 2015
A rocket built by Blue Origin, an aerospace company backed by Jeff Bezos, recently reached space and executed a controlled landing back on Earth, which allows it to be used again. Bezos himself joined Twitter1 this morning to announce the news. Elon Musk, whose SpaceX company has been trying (and failing) to do something similar lately, congratulated Bezos and his team on Twitter2 but also threw a little shade on BO's efforts to reach "space" vs. SpaceX's efforts to reach "orbit".
It is, however, important to clear up the difference between "space" and "orbit", as described well by https://what-if.xkcd.com/58/. Getting to space needs ~Mach 3, but GTO orbit requires ~Mach 30. The energy needed is the square, i.e. 9 units for space and 900 for orbit.
Welcome to Twitter, Jeff.