We Must Think Outside the Rocket Equation

The rocket equation contains three variables. Given any two of these, the third becomes cast in stone. Hope, wishing, or tantrums cannot alter this result. Although a momentum balance, these variables can be cast as energies. They are the energy expenditure against gravity (often called delta V or the change in rocket velocity), the energy available in your rocket propellant (often called exhaust velocity or specific impulse), and the propellant mass fraction (how much propellant you need com...

 Amniotic Sac as Space Suit

The most fundamental innovation is the evolution of another fluid-filled sac, the amnion. in which the embryo floats. Amniotic fluid has roughly the same composition as seawater, so that in a very real sense, the amnion is the continuation of the original fish or amphibian eggs together with its microenvironment, just as a space suit contains an astronaut and a fluid that mimics the earth's atmosphere. All of the rest of the amniote egg is add-on technology that is also required for life in a...

 The Waste of the Shuttle External Tanks

But to grasp just how far our current mindset is from being able to attempt innovation on such a scale, consider the fate of the space shuttle’s external tanks [ETs]. Dwarfing the vehicle itself, the ET was the largest and most prominent feature of the space shuttle as it stood on the pad. It remained attached to the shuttle—or perhaps it makes as much sense to say that the shuttle remained attached to it—long after the two strap-on boosters had fallen away. The ET and the shuttle remained co...