FYI, the existing satellites are in ~700 km circular orbits at 45 degrees inclination. The Falcon 1 user's guide says the performance to that orbit should be about 750 kilograms.The satellite manufacturer (see Skyrocket's link above) says the satellites' propulsion system is hydrazine powered, so presumably they have some ability to maneuver, if limited.I'd speculate that the satellites will be stacked, similar to how prior versions were (see here), and separated by spring pushers or some similarly simple mechanism. At the appropriate intervals, each could make a small orbit raising burn to assume sufficient separation from the previous satellite. Doing so with minimal fuel burn could take a while, but it's feasible.
Quote from: iamlucky13 on 09/04/2009 02:42 amFYI, the existing satellites are in ~700 km circular orbits at 45 degrees inclination. The Falcon 1 user's guide says the performance to that orbit should be about 750 kilograms.The satellite manufacturer (see Skyrocket's link above) says the satellites' propulsion system is hydrazine powered, so presumably they have some ability to maneuver, if limited.I'd speculate that the satellites will be stacked, similar to how prior versions were (see here), and separated by spring pushers or some similarly simple mechanism. At the appropriate intervals, each could make a small orbit raising burn to assume sufficient separation from the previous satellite. Doing so with minimal fuel burn could take a while, but it's feasible.The above almost describes the most reasonable mission architecture, but there are some details left out. Most importantly, the Falcon 1E at this time does not have the capability of injecting 6 different objects into the different required portions of the orbital plane, so a different strategy must be used. Fortunately, the reason why the satellites have a mass 100 kg greater than the 1st generation is due to their active propulsion system ... which provides the answer to everyone's question. What will happen is that that Falcon 1E will put all 6 payloads into a 400 or 500 km orbit, at 45 degrees. Each satellite will put itself into the final 700 km orbit when their low orbit drifts to the required position for the satellite to get into its final position. Globalstar does the same thing, they are put into a transitional 900 km orbit, and then inject themselves into the final 1400 km orbit.So ... all Falcon 1E need do is put 6 142 kg satellites into a 500 km orbit at 45 degrees.
For an interim 500 km / 45° orbit the F1e payload capacity is according to the users guide 850 kg, which could be just enough for 6 satellites, provided there are no performance shortfalls in F1e. I don't know, if the given payload capability includes the mass for the payload adaptor.
Does anyone know the volume of these Satellites. Could it be that volume would be more of a restriction than mass?
Why the heck doesn't the press release state the number of launches? It's kinda weird to leave that detail out.
Quote from: cixelsyD on 09/04/2009 02:57 pmDoes anyone know the volume of these Satellites. Could it be that volume would be more of a restriction than mass?Stowed for launch, they're 1x1x1m cubes, so a Falcon-1e could carry quite a few without problems.
Quote from: Blackstar on 09/04/2009 04:16 pmWhy the heck doesn't the press release state the number of launches? It's kinda weird to leave that detail out.Yeah, weird. Certainly that was agreed upon before signing.I can't really imagine the customer would want that information kept secret, either.
Yeah, weird. Certainly that was agreed upon before signing.
Quote from: iamlucky13 on 09/04/2009 05:57 pmYeah, weird. Certainly that was agreed upon before signing.Is it really so unlikely that they simply don't know exactly how many launches they'll need at this point? Say they understand it'll be somewhere on the order of 5 +/- 1 launches, but the exact number would depend on F1e demonstrated performance. That could also explain why the value of the contract wasn't released. SpaceX added ORBCOMM to their manifest, but simply put 2010-2014 as a placeholder, no breakdown per launch.
Quote from: ugordan on 09/05/2009 11:00 amQuote from: iamlucky13 on 09/04/2009 05:57 pmYeah, weird. Certainly that was agreed upon before signing.Is it really so unlikely that they simply don't know exactly how many launches they'll need at this point? Say they understand it'll be somewhere on the order of 5 +/- 1 launches, but the exact number would depend on F1e demonstrated performance. That could also explain why the value of the contract wasn't released. SpaceX added ORBCOMM to their manifest, but simply put 2010-2014 as a placeholder, no breakdown per launch. If they require 6 F1e launches for their 18 sats, it would have been much more practical to just purchase 2 Rokots (1950kg to LEO) for a lot less money.It has to be a 3-launch scenario - maximum 4 launches.
To launch the 18 satellites into 3 orbital planes it would have required 3 Rokots.
What if it takes 18 launches? How much will SpaceX "lose" on the deal?