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The elephant in the room is the cost of putting a payload in orbit. Even a large difference in materials price will be dwarfed by the cost of fuel and rockets

by beloch 5y ago

The elephant in the room is the cost of putting a payload in orbit. Even a large difference in materials price will be dwarfed by the cost of fuel and rockets if there's even a small weight increase. While wood is a material that will burn up in reentry, there are many others without wood's weight and reliability concerns, and people are starting to look into different construction methods to help satellites burn up on deorbiting reliably. e.g. Instead of joining pieces with bolts, use an epoxy that will fail at reentry temperature, ensuring the satellite breaks up into many small pieces and burns up. This is a fun stunt and good publicity for those involved, but wood probably isn't replacing materials engineered to be lighter and more predictable any time soon.

Retric 5y ago
Cost to LEO has dropped a lot recently. At 951$/kg to LEO wood is probably good enough it’s not an issue for most satellites. Overall strength is probably close enough to be irrelevant in many cases and construction costs could drop quite a bit. It’s not the cost of the carbon fiber that’s at issue it’s how difficult the stuff is to work with.
- brandmeyer 5y ago
  SpaceX is charging 1 megabuck for a 200 kg payload, (5 kUSD/kg). That's still cheap enough that for bespoke spacecraft the launch is still much less expensive than the satellite. What is the basis for your < 1kUSD/kg estimate?
  - Retric 5y ago
    Costs go up for smaller payloads as your paying for more than just weight. As a sanity check a Falcon gets 22,800kg (expendable) and 16,800 (reusable) to LEO. At 5k/kg that would be 84M reusable, apparently they’re charging ~85M for a reusable falcon Heavy launch and Falcon 9 is much cheaper. Actual prices aren’t disclosed but the internal price are quoted at as ~40M new and under 15M refurbished, with 10 total launches per rocket. Assuming the last launch isn’t reusable by design that’s (40M+ 9 * 15M ) ~= 175M to get (16,800 kg * 9 + 22,800kg) = 174,000kg to LEO. That’s under 1k/kg, though I have seen 951$/kg quoted in terms of StarLink’s costs. Clearly they charge customers more, but not 5k/kg more.
    - brandmeyer 5y ago
      Smallsat retail launch prices on Falcon 9 are published. Even if SpaceX is making money hand-over-fist at that price, they are still the cheapest ride in the business. https://www.spacex.com/rideshare/ https://www.spacex.com/rideshare/ ~~disclaimer~~ ~~disclosure~~ excited bragging: my strtup is launching a payload on next week's transporter mission. We payed full retail and have no regrets.
      - Retric 5y ago
        Cool, though they also charge 5k/lb into polar orbits which have significantly lower capacity. Falcon 9 is 16,800kg to LEO but only 9,600kg to a polar orbit. Anyway, clearly larger satellites are much cheaper in terms of cost to LEO, but it’s still a useful datapoint.

by beloch 5y ago

Retric 5y ago

Cost to LEO has dropped a lot recently. At 951$/kg to LEO wood is probably good enough it’s not an issue for most satellites. Overall strength is probably close enough to be irrelevant in many cases and construction costs could drop quite a bit. It’s not the cost of the carbon fiber that’s at issue it’s how difficult the stuff is to work with.

brandmeyer 5y ago
SpaceX is charging 1 megabuck for a 200 kg payload, (5 kUSD/kg). That's still cheap enough that for bespoke spacecraft the launch is still much less expensive than the satellite. What is the basis for your < 1kUSD/kg estimate?
- Retric 5y ago
  Costs go up for smaller payloads as your paying for more than just weight. As a sanity check a Falcon gets 22,800kg (expendable) and 16,800 (reusable) to LEO. At 5k/kg that would be 84M reusable, apparently they’re charging ~85M for a reusable falcon Heavy launch and Falcon 9 is much cheaper. Actual prices aren’t disclosed but the internal price are quoted at as ~40M new and under 15M refurbished, with 10 total launches per rocket. Assuming the last launch isn’t reusable by design that’s (40M+ 9 * 15M ) ~= 175M to get (16,800 kg * 9 + 22,800kg) = 174,000kg to LEO. That’s under 1k/kg, though I have seen 951$/kg quoted in terms of StarLink’s costs. Clearly they charge customers more, but not 5k/kg more.
  - brandmeyer 5y ago
    Smallsat retail launch prices on Falcon 9 are published. Even if SpaceX is making money hand-over-fist at that price, they are still the cheapest ride in the business. https://www.spacex.com/rideshare/ https://www.spacex.com/rideshare/ ~~disclaimer~~ ~~disclosure~~ excited bragging: my strtup is launching a payload on next week's transporter mission. We payed full retail and have no regrets.
    - Retric 5y ago
      Cool, though they also charge 5k/lb into polar orbits which have significantly lower capacity. Falcon 9 is 16,800kg to LEO but only 9,600kg to a polar orbit. Anyway, clearly larger satellites are much cheaper in terms of cost to LEO, but it’s still a useful datapoint.