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That's not very fair comparison for rockets. When people fly in B-747, it also has a pretty significant amount of fuel - and energy - aboard, yet safety complai

by avmich 11y ago

That's not very fair comparison for rockets. When people fly in B-747, it also has a pretty significant amount of fuel - and energy - aboard, yet safety complaints are rare regarding that. So the goal for rockets - for now - could be to become as safe to ride as airplanes are. 100% safety is unobtainable, so shouldn't be a requirement.

rbanffy 11y ago
> the goal for rockets - for now - could be to become as safe to ride as airplanes are. The energy an orbital rocket packs is significantly more than the full fuel load of a 747. The required performance is also much higher. Tolerances are much lower (because of the performance). It'll be quite some time until they get to 747 levels. A worthy goal would be to become as cheap as a 747 at a reasonable safety level. That would be massively disruptive.
- hugh4 11y ago
  A more significant point is that the 747 carries only fuel, the rocket carries fuel and oxidiser, which substantially increases the variety of ways in which things can go interestingly wrong.
Animats 11y ago
"So the goal for rockets - for now - could be to become as safe to ride as airplanes are." If you could build a spacecraft launch system with the weight budget of a commercial airliner, you could get that reliability. The fuel fraction for the Space Shuttle was about 85%; everything else, structure, engines, equipment, and payload, comes out of the remaining 15%. For an airliner, 60% of the mass is non-fuel. Spacecraft are weight-reduced too far to get aircraft reliability. They're just too fragile. Read NASA's "The Tyranny of the Rocket Equation".[1] Space travel with chemical fuels out of Earth's gravity well is just barely possible at all. Chemical fuels just don't have the energy density to do the job well. It's necessary to launch huge booster stacks to put a dinky payload in orbit. That's why, after 50 years, space flight hasn't progressed all that much. Without a denser power source, it will never get much better. [1] http://www.nasa.gov/mission_pages/station/expeditions/expedition30/tryanny.html http://www.nasa.gov/mission_pages/station/expeditions/expedi...

by avmich 11y ago

rbanffy 11y ago

> the goal for rockets - for now - could be to become as safe to ride as airplanes are. The energy an orbital rocket packs is significantly more than the full fuel load of a 747. The required performance is also much higher. Tolerances are much lower (because of the performance). It'll be quite some time until they get to 747 levels. A worthy goal would be to become as cheap as a 747 at a reasonable safety level. That would be massively disruptive.

hugh4 11y ago
A more significant point is that the 747 carries only fuel, the rocket carries fuel and oxidiser, which substantially increases the variety of ways in which things can go interestingly wrong.

Animats 11y ago

"So the goal for rockets - for now - could be to become as safe to ride as airplanes are." If you could build a spacecraft launch system with the weight budget of a commercial airliner, you could get that reliability. The fuel fraction for the Space Shuttle was about 85%; everything else, structure, engines, equipment, and payload, comes out of the remaining 15%. For an airliner, 60% of the mass is non-fuel. Spacecraft are weight-reduced too far to get aircraft reliability. They're just too fragile. Read NASA's "The Tyranny of the Rocket Equation".[1] Space travel with chemical fuels out of Earth's gravity well is just barely possible at all. Chemical fuels just don't have the energy density to do the job well. It's necessary to launch huge booster stacks to put a dinky payload in orbit. That's why, after 50 years, space flight hasn't progressed all that much. Without a denser power source, it will never get much better. [1] http://www.nasa.gov/mission_pages/station/expeditions/expedition30/tryanny.html http://www.nasa.gov/mission_pages/station/expeditions/expedi...