Contact across the Solar System

A Grand Unified Theory of Earth Spaceflight

Early in 1973, the Americans sent Pioneer 11 to Jupiter, and this one was to continue to Saturn after flying by Jupiter. Late that year, they sent Mariner 10 to Venus, and onward to Mercury. After landing their two Viking spacecraft on Mars, they sent Voyagers 1 and 2 to Jupiter and Saturn, and they planned for Voyager 2 to continue to Uranus and Neptune if Voyager 1 did well enough. In the meantime, the Russians were successfully landing their spacecraft on Venus and failing to do so on Mars. The multiplanet missions were a new wrinkle in Earther spaceflight, missions all done with gravity assists, using a planet's gravity to continue onwards in an appropriate direction.

In the SSC worlds, some students of Earther spaceflight developed a sort of grand unified theory of it, a theory that explained many of its quirks and oddities and bizarre features. They called it their "fuel frugality thesis". It states that the Earthers want to scrimp on rocket fuel as much as possible, and that doing so has a big influence on their mission designs. By the late 1970's, the Earthers had done enough interplanetary spaceflight to enable working out this thesis in detail.

* Staging. Discarding parts of one's rocket as one goes. That's necessary because an empty part is dead weight and discarding it saves on fuel. But it produces absurdities like the Apollo astronauts departing atop a huge rocket and returning in a small spacecraft not much larger than they themselves.

* Crashing into atmospheres. That seems like the last thing that any sensible pilot would want to do, but the Earthers do it, without trying to slow down. The Earthers put heat shields onto their spacecraft, and that protects them well enough, even if the heat shields themselves don't survive very well.

* Arriving at Mars and Venus in periodic waves. These waves are exactly as predicted from the lowest-energy transfer orbits, the orbits that require the least amount of rocket fuel. The spacecraft travel times are also what's predicted from that theory.

* Extensive use of remote-controlled, automated spacecraft. Without people to keep alive in them, many spacecraft can be made relatively small, thus saving on rocket fuel.

* One-way missions. If a spacecraft does not return, it does not need the rocket fuel necessary for doing so.

* Flybys. If a spacecraft does not go into orbit around a planet, it does not need the rocket fuel necessary for doing so. In fact, a flyby has been the first or only kind of encounter for most of the celestial bodies that the Earthers have explored.

* Gravity-assist maneuvering. That's using a planet's gravity to redirect a spacecraft's motion, speeding it up or slowing it down as appropriate. A spacecraft thus only needs enough fuel for small adjustments of its travels.

* Slow travels, especially in the outer Solar System. Traveling faster would require more rocket fuel, of course.

As the years went by, Earther spaceflight stayed consistent with that thesis. It was not even developing very fast, with some rocket designs being used for years without much change. The American Space Shuttle was a valiant effort to develop a reusable spacecraft, but it needed lots of maintenance and it couldn't be flown that often. It wasn't even a good substitute for the more usual kind of Earther rocket, the kind that gets discarded as it goes.

Even more bizarre, no Earther went beyond low Earth orbit after Apollo 17, though a lot of Earthers did go into low Earth orbit in those years. It supported the theory that sending Earthers to the Moon was a big technology stunt, and it cast a lot of doubt on whether Earthers would ever reach Mars, let alone any other Solar-System destination beyond their moon, anytime soon. All the Earthers were sending beyond their moon were automated spacecraft.

To many SSC people, it seemed evident that Earther spaceflight was unlikely to be a threat to their worlds in the foreseeable future. The main exception was some Martians who got all worked about how the Earthers supposedly want to conquer Mars. But they continued to be a minority among their fellow Martians. Most others either felt that Earther explorers were welcome or else felt that Earthers continued to be absurdly backward.

Kalna and Ilmuth ended up answering a lot of questions about these issues, with the two tending to specialize in different aspects of Earther spaceflight, Kalna in more overall issues and Ilmuth in the mechanics of it. Ramu invited the two to the Saturnian system after Pioneer 11 passed through it in 1979, and they gave some talks there also. Some people there had incredibly naive notions of what the Earth was like, like that it was a big garden and that it was a big war zone.

While all this was going on, there was some drama about Earther energy supplies.

In 1973, after Israel beat the Arab nations in yet another war, the Arab oil exporters stopped exporting oil to nations that they considered excessively pro-Israel. That produced a big oil-supply crunch in those nations, especially the United States. When Kalna learned of it, she thought back to that meeting with that petroleum geologist. Economic warfare wasn't something that he'd thought of.

Then in 1979, Iranian Islamists overthrew the Shah of Iran, and their doing so disrupted the nation's oil exports. That caused another oil-supply crunch. Kalna thought of that geologist again, and she tried to think of what might be next. A shooting war over oil? That indeed happened in Kuwait in 1991, and in Iraq in 2003, and as she learned of them, Kalna got rather depressed about how prescient she was.