danielbarger left a comment to yesterday's post about Starship:
As long as we are limited to chemical rockets where 90% of the weight is fuel and rocket with only 10% payload we will never be able to make use of the solar systems resources efficiently. The problem is there is no viable alternative...not even a theoretical one. It's an enormous hurdle to becoming a space faring species.I have two comments.
- Efficiency factors into the price. Starship may get the cost of payload to orbit down to $50/pound. That's what King Crab costs. It's hard to call this "inefficient" when it is reducing cost by three orders of magnitude.
- Agreed with danielbarger and others that this does not get us to Interstellar travel. The DC-3 didn't get us to the moon, either, but it was a damn fine start.
Casey Handmer covers this well in the post I linked to:
Consider the two critical metrics: Dollars per tonne ($/T) and tonnes per year (T/year). Any effective space transport cargo logistics system must aggressively optimize both these metrics simultaneously. Starship is intended to reach numbers as low as $1m/T and 1000 T/year for cargo soft landed on the Moon. Apollo achieved about $2b/T and 2 T/year for cargo soft landed on the Moon. Constellation 2.0 as described above [NASA's SLS-to-the-moon program - Borepatch] would be more like $4b/T and 2 T/year.
Not only is this architecture obviously worse than Starship, it’s also significantly worse than Apollo or any existing lunar delivery system. For example, the Blue Moon lander could be flown on Falcon Heavy, delivering perhaps 10 T to the surface for <$200m. Indeed, the Constellation architecture is worse than the current state-of-the-art by roughly the same factor that Starship promises to be better. That is, it takes the key metrics of $/T and T/year and runs as far as possible in the wrong direction. It is also a programmatic dead end, since none of the individual components can be upgraded in a meaningful way without restarting development of the entire system from scratch. It’s an expensive, interlocking failure.
I'd say that Starship is an enormous efficiency improvement.
4 comments:
One of the things to know about the launch industry now is that it's basically SpaceX and everybody else. Last year, they not only launched more times than China, the launched more than the the rest of the world combined.
Next Spaceflight says that on a ride sharing mission launching Sunday morning, a 50kg payload costs $300,000. $6000/kg is still $2700/lb, but that has to help small businesses and even college clubs.
Yes....recent developments have improved efficiency. But going from NASA to SpaceX/Starship is like switching a steam locomotive from fuel to coal for travel and transport needs when what you need is a Boeing 747. But the secrets of flight are still unknown. We MUST learn to negate and control gravity...IF that is possible...in order to efficiently leave Earth's gravity. Chemical rockets will never be adequate for large scale space travel.
Chemical rockets get you into and out of orbit. Continuous thrust (nuclear) engines maneuver between the planets. You'd still have to stop somewhere occasionally to pick up reaction mass for the thrusters. TANSTAAFL
One of the underrated problems is your own ship slowly becoming more and more radioactive due to the solar wind. Solar sails could actually help with this, at the cost of becoming radioactive themselves. And they're only useful in certain directions.
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