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...or 70 satellites every tenth launch. Another poster said their test satellites were 400kg, and the falcon 9 can hoist 22,800kg to LEO according to Wikipedia

by elihu 9y ago

...or 70 satellites every tenth launch. Another poster said their test satellites were 400kg, and the falcon 9 can hoist 22,800kg to LEO according to Wikipedia. That gives a ratio of 57 satellites per Falcon 9. The final satellite design might be heavier or lighter, the desired orbit may require more fuel and less payload, the satellites may require some additional hardware for securely storing and deploying them, and the current F9 may be superseded by bigger or more efficient or cheaper per payload kg rockets over the course of the next few years, so 70 per launch is probably a good guess to within an order of magnitude. If they wait for the BFR, that (also according to Wikipedia) has a projected payload to LEO of 150,000kg or 375 test-satellite-equivalent masses. If it's cheaper per kg, they might just use that.

nickik 9y ago
The F9 will be volume constricted not weight. Maybe they will build a bigger fairing, but that has some problems as well. People are currently think they can send more then 10-20 on one flight.
Tuna-Fish 9y ago
F9 can do 22,800kg per launch when flying expendable. I don't think SpaceX intends to many expendable launches for their own constellations. iirc the max payload to LEO when flying recoverable to barge is ~18,000kg, and when returning to launch site ~13,000kg. To minimize costs, I think it makes more sense for them to do RTLS than barge landings, especially as barge landings put hard limits on launch frequency (the barges aren't very fast). However, even that 13,000kg is probably too high, because that is to an orbit that is probably lower than the 1150-1300km ones they are going to use for this. However, for practical reasons enlarging the fairings can be more expensive than just flying more, so the limit of satellites per launch is probably set by how many they can fit into the standard F9 payload fairing. (1). > If they wait for the BFR They can't wait for very long, or they might lose their spectrum allocation. The contract requires them to put up half of their constellation in 6 years. (1) page 36 of: http://www.spacex.com/sites/spacex/files/falcon_9_users_guide_rev_2.0.pdf http://www.spacex.com/sites/spacex/files/falcon_9_users_guid...

by elihu 9y ago

nickik 9y ago

The F9 will be volume constricted not weight. Maybe they will build a bigger fairing, but that has some problems as well. People are currently think they can send more then 10-20 on one flight.

Tuna-Fish 9y ago

F9 can do 22,800kg per launch when flying expendable. I don't think SpaceX intends to many expendable launches for their own constellations. iirc the max payload to LEO when flying recoverable to barge is ~18,000kg, and when returning to launch site ~13,000kg. To minimize costs, I think it makes more sense for them to do RTLS than barge landings, especially as barge landings put hard limits on launch frequency (the barges aren't very fast). However, even that 13,000kg is probably too high, because that is to an orbit that is probably lower than the 1150-1300km ones they are going to use for this. However, for practical reasons enlarging the fairings can be more expensive than just flying more, so the limit of satellites per launch is probably set by how many they can fit into the standard F9 payload fairing. (1). > If they wait for the BFR They can't wait for very long, or they might lose their spectrum allocation. The contract requires them to put up half of their constellation in 6 years. (1) page 36 of: http://www.spacex.com/sites/spacex/files/falcon_9_users_guide_rev_2.0.pdf http://www.spacex.com/sites/spacex/files/falcon_9_users_guid...