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>"wasteful to see that mission profile with the center booster burning up without even trying." My understanding was that the intended orbit / mission profile

>"wasteful to see that mission profile with the center booster burning up without even trying." My understanding was that the intended orbit / mission profile means that they must fly the center core in expendable mode. Otherwise, the satellite wouldn't be able to reach the intended orbit with the intended amount of fuel for the mission's duration.

bpodgursky 4y ago
Hopefully once Starship launches, we'll never see a disposable core again.
- verdverm 4y ago
  They are different classes of launch vehicles. This payload is not really a good one for starship, and conversely, starlinks will never fly on heavy
  - bpodgursky 4y ago
    I'm pretty sure the goal with Starship is that the economics are so much better that it's used even for awkward launches. I do not believe they are targeting Falcon Heavy launches in the long-term, assuming the best-case Starship scenarios.
  - bryanlarsen 4y ago
    Yes, it's really odd to see a GEO launch rather than a GTO at launch. GTO is a geosynchronous transfer orbit with apogee at GEO and perigee at LEO that uses the satellite's thrusters to circularize to full GEO. Starship can't do a GEO directly, it would need refueling or a kick stage to do GEO. Since we really don't know why the Space Force wanted direct GEO we can't know for sure if refueling or a kick stage would have met requirements or not. Would it be good enough as long as the satellite to stay hidden inside the fairing during refueling?
    - ErikCorry 4y ago
      They wanted to use it before Xmas to keep an eye on Ukraine, and they didn't want to have to wait?
- oconnor663 4y ago
  Even a reusable rocket reaches the end of its service life eventually, and at that point it can make sense for the last flight to be expendable.
  - chroma 4y ago
    It's probably more cost-effective to keep the craft and scrap it. The structure itself is a significant amount of steel, and the engines contain expensive superalloys.
    - oorza 4y ago
      If a spacefaring vessel lasts long enough that it needs to be decomissioned due to wear and tear, that mf'er belongs ONLY in a museum. I hope to live to the day where that isn't universally true, but it is not today.
      - TOMDM 4y ago
        Makes sense for NASA to donate, but say SpaceX could recover $10m in materials from an expended Starship, that's a steep ask. When the time comes, I hope they choose to donate it to a museum, or if not, the funds are raised to buy it off them.
        bombcar 4y ago
        I mean it's a $10m ask/potential write-off, so there is that. The "first one" will be even more rare/valuable and NASA might make a deal for it.
      - chroma 4y ago
        I'm sure the first couple will be preserved, but they'll quickly become as common as derelict airplanes or ships. Has SpaceX kept any of their Falcon 9 boosters besides the first one that landed? I think the old ones are disassembled for analysis, then scrapped.
        4y ago
nuccy 4y ago
Likely yes. Though there may be few ways to land the core booster: 1. Expend side-boosters to save enough fuel in the core for the entry+landing burn. 2. Land side-boosters on drone ships instead of flying back to land. First option is likely the least favorable one, since two side-boosters combined price may be higher than the single core. Even though the core itself is likely more expensive than a single side-booster, since it caries the load of the payload plus side-loads from both side-boosters. Second option may be complicated logistically due to a lack of drone-ships. Landing three (or even two) rockets in the ocean was never done before.
- deleted 4y ago
  [deleted]
elfchief 4y ago
At one point (I don't know if it's still the case) for certain launches the US government laid claim to "100% of the thrust available from a booster" or somesuch, basically not leaving anything left over for landings. I'm not sure it was ever documented why they had this requirement. What surprised -me- was that all three boosters were brand new, rather than, say, expending a booster that's already flown half a dozen times or such.
- xeromal 4y ago
  Just guessing but maybe 100% of thrust available = statistically safer or something like that?
  - bombcar 4y ago
    Or gives them more lee-way for maneuvering or - makes it a tiny bit harder for spies to figure out what orbit they're going to place the satellite before the launch. Or because someone asked "how high" and got back "as high as you can go".
    - snovv_crash 4y ago
      It could be something with a large fuel tank that can be adjusted in capacity so that it will be 100% of whatever Falcon can offer for the target orbit.
- Denvercoder9 4y ago
  > What surprised -me- was that all three boosters were brand new, rather than, say, expending a booster that's already flown half a dozen times or such. Using new boosters was probably a contract requirement, but even if it wasn't, the Falcon Heavy center core isn't interchangeable with regular Falcon 9 cores, as it has to be strengthened to handle the additional load the side boosters put on it.

bpodgursky 4y ago

Hopefully once Starship launches, we'll never see a disposable core again.

verdverm 4y ago
They are different classes of launch vehicles. This payload is not really a good one for starship, and conversely, starlinks will never fly on heavy
- bpodgursky 4y ago
  I'm pretty sure the goal with Starship is that the economics are so much better that it's used even for awkward launches. I do not believe they are targeting Falcon Heavy launches in the long-term, assuming the best-case Starship scenarios.
- bryanlarsen 4y ago
  Yes, it's really odd to see a GEO launch rather than a GTO at launch. GTO is a geosynchronous transfer orbit with apogee at GEO and perigee at LEO that uses the satellite's thrusters to circularize to full GEO. Starship can't do a GEO directly, it would need refueling or a kick stage to do GEO. Since we really don't know why the Space Force wanted direct GEO we can't know for sure if refueling or a kick stage would have met requirements or not. Would it be good enough as long as the satellite to stay hidden inside the fairing during refueling?
  - ErikCorry 4y ago
    They wanted to use it before Xmas to keep an eye on Ukraine, and they didn't want to have to wait?
oconnor663 4y ago
Even a reusable rocket reaches the end of its service life eventually, and at that point it can make sense for the last flight to be expendable.
- chroma 4y ago
  It's probably more cost-effective to keep the craft and scrap it. The structure itself is a significant amount of steel, and the engines contain expensive superalloys.
  - oorza 4y ago
    If a spacefaring vessel lasts long enough that it needs to be decomissioned due to wear and tear, that mf'er belongs ONLY in a museum. I hope to live to the day where that isn't universally true, but it is not today.
    - TOMDM 4y ago
      Makes sense for NASA to donate, but say SpaceX could recover $10m in materials from an expended Starship, that's a steep ask. When the time comes, I hope they choose to donate it to a museum, or if not, the funds are raised to buy it off them.
      - bombcar 4y ago
        I mean it's a $10m ask/potential write-off, so there is that. The "first one" will be even more rare/valuable and NASA might make a deal for it.
    - chroma 4y ago
      I'm sure the first couple will be preserved, but they'll quickly become as common as derelict airplanes or ships. Has SpaceX kept any of their Falcon 9 boosters besides the first one that landed? I think the old ones are disassembled for analysis, then scrapped.
      - 4y ago

nuccy 4y ago

Likely yes. Though there may be few ways to land the core booster: 1. Expend side-boosters to save enough fuel in the core for the entry+landing burn. 2. Land side-boosters on drone ships instead of flying back to land. First option is likely the least favorable one, since two side-boosters combined price may be higher than the single core. Even though the core itself is likely more expensive than a single side-booster, since it caries the load of the payload plus side-loads from both side-boosters. Second option may be complicated logistically due to a lack of drone-ships. Landing three (or even two) rockets in the ocean was never done before.

deleted 4y ago
[deleted]

elfchief 4y ago

At one point (I don't know if it's still the case) for certain launches the US government laid claim to "100% of the thrust available from a booster" or somesuch, basically not leaving anything left over for landings. I'm not sure it was ever documented why they had this requirement. What surprised -me- was that all three boosters were brand new, rather than, say, expending a booster that's already flown half a dozen times or such.

xeromal 4y ago
Just guessing but maybe 100% of thrust available = statistically safer or something like that?
- bombcar 4y ago
  Or gives them more lee-way for maneuvering or - makes it a tiny bit harder for spies to figure out what orbit they're going to place the satellite before the launch. Or because someone asked "how high" and got back "as high as you can go".
  - snovv_crash 4y ago
    It could be something with a large fuel tank that can be adjusted in capacity so that it will be 100% of whatever Falcon can offer for the target orbit.
Denvercoder9 4y ago
> What surprised -me- was that all three boosters were brand new, rather than, say, expending a booster that's already flown half a dozen times or such. Using new boosters was probably a contract requirement, but even if it wasn't, the Falcon Heavy center core isn't interchangeable with regular Falcon 9 cores, as it has to be strengthened to handle the additional load the side boosters put on it.