Developing expendable rockets is always going to be painful and expensive. Throwing the whole rocket away on each attempt not only costs a lot, it also hampers figuring out just what went wrong because you don't get the rocket back for inspection. Henry Spencer attemptbackcost share on social
Liquid oxygen is one of the cheapest manufactured substances on Earth. In large quantities, it costs pennies per kilogram - cheaper than milk or beer. Henry Spencer beercheapcost Change image and share on social
Trying to build a spaceship by making an aeroplane fly faster and higher is like trying to build an aeroplane by making locomotives faster and lighter - with a lot of effort, perhaps you could get something that more or less works, but it really isn't the right way to proceed. Henry Spencer aeroplanebuildeffort share on social
Sometimes people wonder why aeroplanes are so cheap and rockets are so expensive. Even the most superficial comparison shows one obvious difference: aeroplane engines use outside air to burn their fuel, while rockets have to carry their own oxidisers along. Henry Spencer aeroplaneairburn share on social
SpaceX does seem to have had a run of bad luck, with its first three launches all failing. Henry Spencer badfaillaunch Change image and share on social
Rocket engines generally are simpler than jet engines, not more complicated. Henry Spencer complicateenginegenerally Change image and share on social
Spaceflight, especially in the Mercury spacecraft, clearly wasn't going to be much like flying an airplane. Henry Spencer airplaneflymercury Change image and share on social
The key virtue of orbital assembly is that it eliminates the tight connection between the size of the expedition and the size of the rockets used to launch it. Henry Spencer assemblyconnectioneliminate Change image and share on social
The communications delays between Earth and Mars can be half an hour or more, so the people on the ground can't participate minute by minute in Mars surface activities. Henry Spencer activitycommunicationdelay Change image and share on social
Sometimes a malfunctioning test setup actually gives the tested system a chance to show what it can do in an unrehearsed emergency. During a test of an Apollo escape system in the 1960s, the escape system successfully got the capsule clear of a malfunctioning test rocket. Henry Spencer 1960sapollocapsule share on social
