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Landing still requires a lot of fuel, which needs fuel to be carried up. It was a waste and still is. If they come up with reusable fished from the ocean, that

by LtWorf 3y ago

Landing still requires a lot of fuel, which needs fuel to be carried up. It was a waste and still is. If they come up with reusable fished from the ocean, that'd be useful.

tekla 3y ago
Nobody cares if some performance is lost when you are good enough for 99% of payloads and you save tons of money by retrieving the expensive part of the rocket
Dig1t 3y ago
It also takes extra fuel to land an airplane. Does it make sense to just throw the whole plane away after one use to save the extra landing fuel?
- LtWorf 3y ago
  This comparison would make sense if planes were leaving orbit.
  - Dig1t 3y ago
    I would love to hear an explanation as to why that makes a difference?
    - LtWorf 3y ago
      Planes work by heating up air and then going fast enough to fly? While rockets have to eject stuff and move the centre of mass outside of themselves. Also they need to leave the gravity well while planes don't do that? It's completely different.
elteto 3y ago
You have absolutely no idea what you are talking about. It doesn’t require a “lot” of fuel. It depends on the mission profile. And guess what you can do? Run 9 LEO missions with the same booster and throw it away on the 10th with a GEO mission. That’s freaking incredible.
- signatoremo 3y ago
  A booster just completed its 18th flight last week. 18 flights within 3 years. They’ve raised the limit for Starlink launches to 20 reuses.
brookst 3y ago
Cost of refurbishing a booster fished from the ocean would dwarf the fuel cost and lost capacity. Not to mention the extra weight and cost you'd incur building a booster that can impact the ocean at speed.
pmontra 3y ago
They have to land a nearly empty booster. They don't need as much fuel as they needed to launch. Anyway, here are the economics according to Musk https://www.inverse.com/innovation/spacex-elon-musk-falcon-9-economics https://www.inverse.com/innovation/spacex-elon-musk-falcon-9... The breakeven is closer to 2 launches than to 3, so 3.
pixl97 3y ago
Fished from the ocean... ok... Do you think you can fall from space and hit the ocean and be reusable? To land in the water and not spatter yourself you'll need to be going less than 20 miles per hour, which is a hell of a lot less then the 1000+MPH a rocket booster is going, and second stage would turn to plasma if it didn't slow down first.
avmich 3y ago
> Landing still requires a lot of fuel, which needs fuel to be carried up. That's true, and that reduces the payload of the returning stage. To have it working, you either have to reduce the payload or to increase the size of the stage. In both cases the payload weight to liftoff weight decreases. > It was a waste and still is. That's false, as in exchange the operator gets the stage back to be reused on the next flight. That's usually a huge saving in costs. Fuel is relatively cheap, and to make a rocket somewhat bigger or a payload somewhat smaller does relatively small change to the price of a kilogram to LEO comparing to the opportunity not to pay for the stage hardware on the next flight. Overall SpaceX made a huge improvement in costs and moved the world launch industry quite a bit forward.
phurley 3y ago
I agree with the other commenters about this being incorrect, but there is in hindsight an even bigger deal -- getting to examine the rocket (not fished out of salt water) after the flight and learn from that is huge and often overlooked.
- ethbr1 3y ago
  AND run to failure. If a booster can survive 20 launches, it probably has most of the gotchas for launch #1 ironed out.
coderenegade 3y ago
At worst you can still operate the vehicle the same way you would a conventional rocket, so it's strictly better in that sense. For every mission in which the cost of bringing the rocket back is lower than the cost of manufacturing a new one, you come out ahead.

by LtWorf 3y ago

Landing still requires a lot of fuel, which needs fuel to be carried up. It was a waste and still is. If they come up with reusable fished from the ocean, that'd be useful.

tekla 3y ago

Nobody cares if some performance is lost when you are good enough for 99% of payloads and you save tons of money by retrieving the expensive part of the rocket

Dig1t 3y ago

It also takes extra fuel to land an airplane. Does it make sense to just throw the whole plane away after one use to save the extra landing fuel?

LtWorf 3y ago
This comparison would make sense if planes were leaving orbit.
- Dig1t 3y ago
  I would love to hear an explanation as to why that makes a difference?
  - LtWorf 3y ago
    Planes work by heating up air and then going fast enough to fly? While rockets have to eject stuff and move the centre of mass outside of themselves. Also they need to leave the gravity well while planes don't do that? It's completely different.

elteto 3y ago

You have absolutely no idea what you are talking about. It doesn’t require a “lot” of fuel. It depends on the mission profile. And guess what you can do? Run 9 LEO missions with the same booster and throw it away on the 10th with a GEO mission. That’s freaking incredible.

signatoremo 3y ago
A booster just completed its 18th flight last week. 18 flights within 3 years. They’ve raised the limit for Starlink launches to 20 reuses.

brookst 3y ago

Cost of refurbishing a booster fished from the ocean would dwarf the fuel cost and lost capacity. Not to mention the extra weight and cost you'd incur building a booster that can impact the ocean at speed.

pmontra 3y ago

They have to land a nearly empty booster. They don't need as much fuel as they needed to launch. Anyway, here are the economics according to Musk https://www.inverse.com/innovation/spacex-elon-musk-falcon-9-economics https://www.inverse.com/innovation/spacex-elon-musk-falcon-9... The breakeven is closer to 2 launches than to 3, so 3.

pixl97 3y ago

Fished from the ocean... ok... Do you think you can fall from space and hit the ocean and be reusable? To land in the water and not spatter yourself you'll need to be going less than 20 miles per hour, which is a hell of a lot less then the 1000+MPH a rocket booster is going, and second stage would turn to plasma if it didn't slow down first.

avmich 3y ago

> Landing still requires a lot of fuel, which needs fuel to be carried up. That's true, and that reduces the payload of the returning stage. To have it working, you either have to reduce the payload or to increase the size of the stage. In both cases the payload weight to liftoff weight decreases. > It was a waste and still is. That's false, as in exchange the operator gets the stage back to be reused on the next flight. That's usually a huge saving in costs. Fuel is relatively cheap, and to make a rocket somewhat bigger or a payload somewhat smaller does relatively small change to the price of a kilogram to LEO comparing to the opportunity not to pay for the stage hardware on the next flight. Overall SpaceX made a huge improvement in costs and moved the world launch industry quite a bit forward.

phurley 3y ago

I agree with the other commenters about this being incorrect, but there is in hindsight an even bigger deal -- getting to examine the rocket (not fished out of salt water) after the flight and learn from that is huge and often overlooked.

ethbr1 3y ago
AND run to failure. If a booster can survive 20 launches, it probably has most of the gotchas for launch #1 ironed out.

coderenegade 3y ago

At worst you can still operate the vehicle the same way you would a conventional rocket, so it's strictly better in that sense. For every mission in which the cost of bringing the rocket back is lower than the cost of manufacturing a new one, you come out ahead.