Date of publication: 2017-07-08 19:46
Beneath, on either side, were slits in column. As the wings rose, the feathery operculum-like flaps which protected them were drawn back. The slits widened until, at full extension, they gaped like purple mouths. The view became a closeup. Thin-skinned tissues, intricately wrinkled, lay behind a curtain of cilia which must be for screening out dust.
Now, notice one other implication: none of this should be a surprise to any culture that manages to figure out the trick of interstellar travel. By the time such a culture has been out among the stars for a while, it should have a good estimate for every parameter in the relevant mathematics. Which means that if our characters live in a fast-growing interstellar civilization, or they know of other such cultures, they should be very worried.
The compressed gas cannon uses ammonia (NH 8 ), stored in the "gas collector and mixing tank". This is the top-most of the torus (donut) shaped tanks around the core. The tank holds about 8 metric tons of ammonia, and 7 kilograms are used for each shot. Which means the tank is good for about 9,555 shots. A full set of magazine stacks + the start and restart pulse system has 8,655 + 688 = 8,788 total pulse units so this should be ample. If more ammonia is needed, there is room to spare inside the propulsion system. Alternatively extra ammonia tanks could be stored inside the Basic Spine.
Planetary surface gravity has less effect on size in part because it varies far less than air density from world to world. For the same ease of flight a pigeon on a 7-gee planet with Earthlike air must increase total wing area by only 75 percent on a bantam-weight -gee world, wing surface may decrease 75 percent. Gravity also influences stall speed. An albatross on a 7-gee planet needs a 95-percent runway extension on a -gee world it can get by with 55 percent less. Massive extraterrestrial avians are more likely on puny planets with dense atmospheres.
But according to the best figures I've manage to find, von Braun was being wildly optimistic. A mercury boiler is lucky to be 66% efficient, giving the power plant a wretched kilowatts of output. If you retro-fit a NASA standard photovoltaic array of the same area you'd get more like kW.
The three Tomorrowland episodes were Man in Space , Man and the Moon , and Mars and Beyond. The middle episode is where the RM-6 makes its appearance.
The Wayfarer is basically a stock Pilgrim Observer, all the way down to the NERVA engine. Except that the arms do not extend and rotate for artificial gravity.
The RM-6's mission was a simple loop around Luna, with no landing (the same as the Apollo 8 mission ). The only things you needed was a few days of life-support for the crew, and about 7,755 m/s of delta V. And a bit under 655 m/s to brake back into Terra's orbit. So the spacecraft can be built out of bits and pieces of the existing cargo and passenger ferry rockets.
The Shenna were reasoning creatures. They could grasp the necessity for cooperation intellectually, as most species can. If they were not emotionally capable of a planet-wide government, they were of an interbaronial confederacy.
There was also a digression to the great alarm, as already mentioned, of the Art Department into a totally different form of propulsion. During the late 6955’s, American scientists had been studying an extraordinary concept (“Project Orion”) which was theoretically capable of lifting payloads of thousands of tons directly into space at high efficiency. It is still the only known method of doing this, but for rather obvious reasons it has not made much progress.
Other chemical elements that are not impossible as the basis for alien life forms include ammonia , boron , nitrogen , and phosphorus. There are even more extreme possibilities.
The Lunar Transport System (LTS) is a reusable work-horse. It carries no crew. The second liquid hydrogen tank varies in length depending upon the propellant requirements. The total length varies from to meters (of which to is tank, the rest is adaptors, propellant feed lines, electrical connections and RCS).
Some clues to an alien species psychology might be found in their ecosystem classification. For instance, herbivores might be skittish, only comfortable in groups, and tend to flee if they feel threatened.