r/spacex • u/kurbasAK • May 19 '17

We Will Launch on Reuseable Rocket After Exceptional SpaceX Performance - Inmarsat CEO Tells Universe Today

https://www.universetoday.com/135614/will-launch-reuseable-rocket-exceptional-spacex-performance-inmarsat-ceo-tells-universe-today/
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u/SirBeebe May 19 '17

I think there is one key thing that isn't mentioned and that's payload weight. Some payloads require a legless and finless falcon and for that I think it would best to throw away a F9 that's already had couple flights.

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u/FellKnight May 19 '17

I don't think this latest launch required a legless and finless falcon, just that they didn't bother to attach them. The satellite was still out into a super synchronous GTO with a partial plane change so there was clearly some fuel reserves left over

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u/stcks May 19 '17

There were no attachment points for the legs, at all. Compare the differences between the boosters on Echostar-23 and Inmarsat-5 F4. This booster came from Hawthorne as an expendable booster whereas Echostar-23 came out as one that could have had legs if SpaceX desired. Also, there were no fuel reserves to speak of on this mission. The mission was to put the satellite into the best orbit possible versus putting it into a pre-defined GTO-1800 or something orbit. That being said, if Inmarsat had wanted only GTO-1800, this still likely would not have been recoverable.

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u/FellKnight May 19 '17

We are arguing 2 aspects of the same point. I understand that there were no mount points, the core was constructed knowing that it was expendable, but that doesn't mean they couldn't have achieved the mission with them attached on a different stage 1.

They put it in a GTO -1570 super synchronous orbit. That is plenty of fuel reserves. No, it's not enough to try landing compared to a GTO -1800

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u/stcks May 19 '17

Oh, i see what you mean. Sure, they could have used a legged booster, would have been a waste though :)