3 ms·

These are not great comparison numbers. When rockets fly passengers it's ~4 people as compared to ~200 for a plane. A modern 737 has a max fuel load of almost

These are not great comparison numbers. When rockets fly passengers it's ~4 people as compared to ~200 for a plane. A modern 737 has a max fuel load of almost 30000L of jet fuel [1]. The density of jet fuel is 775-840 g/L [2]. Let's take 800g/L so that we can just multiply the lead numbers - that gives 24,000 kg of fuel. According to spaceflight101 [3], the Falcon 9 uses 123,570 kg of RP-1 (similar to jet fuel) in the first stage and 32,300 kg of RP-1 in the second stage for a total of 155,870 kg, which is about 6.5x the total fuel load on the 737. Falcon 9 launched 98 times last year (which includes some Falcon Heavy flights which have more fuel, but I don't think it changes the big picture here). There are 5000 737's in active service [4]. Most of them are probably flying several times per day, but if we just assume once per day that's 1,825,000 flights. That's almost 3000x the amount of CO2 as produced by all those F9 flights. And that's just 737s. 1. https://en.wikipedia.org/wiki/Boeing_737#Specifications https://en.wikipedia.org/wiki/Boeing_737#Specifications 2. https://en.wikipedia.org/wiki/Jet_fuel https://en.wikipedia.org/wiki/Jet_fuel 3. https://spaceflight101.com/spacerockets/falcon-9-ft/ https://spaceflight101.com/spacerockets/falcon-9-ft/ 4. https://simpleflying.com/boeing-737-in-service-stored/ https://simpleflying.com/boeing-737-in-service-stored/

flashback2199 3y ago
Right, I think people are misunderstanding a key point here, which is that SpaceX, Blue Origin, etc would really like to see rockets be an alternative to airplanes, in which case we are talking about a dramatically increased number of launches.
- avhon1 3y ago
  > SpaceX, Blue Origin, etc would really like to see rockets be an alternative to airplanes Why? Rockets are intrinsically less efficient and less safe than airplanes. Why would they try to compete for use cases where they are at such a disadvantage, and where they have to-date shown no interest in competing with fixed-wing aircraft? The closest those companies have done to showing interest in pitching rockets against aircraft is Elon Musk saying that his company will offer ultra-high-speed flights via rocket, which is more like a Concorde-killer 25 years after the Concorde got killed by its own costs.
  - flashback2199 3y ago
    You have answered your own question.
  - njarboe 3y ago
    It would just be for very long flights. 45 minutes from New York to New Zealand instead of 17hr. That is a big difference. Plus you get to go into orbit (or close to it) for an amazing view/ride. You would have a huge number of people per year at $5-10k per ticket.

flashback2199 3y ago

Right, I think people are misunderstanding a key point here, which is that SpaceX, Blue Origin, etc would really like to see rockets be an alternative to airplanes, in which case we are talking about a dramatically increased number of launches.

avhon1 3y ago
> SpaceX, Blue Origin, etc would really like to see rockets be an alternative to airplanes Why? Rockets are intrinsically less efficient and less safe than airplanes. Why would they try to compete for use cases where they are at such a disadvantage, and where they have to-date shown no interest in competing with fixed-wing aircraft? The closest those companies have done to showing interest in pitching rockets against aircraft is Elon Musk saying that his company will offer ultra-high-speed flights via rocket, which is more like a Concorde-killer 25 years after the Concorde got killed by its own costs.
- flashback2199 3y ago
  You have answered your own question.
- njarboe 3y ago
  It would just be for very long flights. 45 minutes from New York to New Zealand instead of 17hr. That is a big difference. Plus you get to go into orbit (or close to it) for an amazing view/ride. You would have a huge number of people per year at $5-10k per ticket.