...Zenit-3SL can do 6.16 to a 1,477m/s deficit GTO. That's a ~95m/s difference. If they used less delta-v GTO, and they didn't had structural limits on the rocket, it would be much higher performance. Using a linear approximation I get 7.8 tonnes.
Quote from: baldusi on 05/16/2017 08:10 pmQuote from: Targeteer on 05/16/2017 04:20 pm42698 INMARSAT 5-F4 2017-025A 1401.67min 24.50deg 69839km 381km 42699 FALCON 9 R/B 2017-025B 1410.43min 24.47deg 70181km 384kmRoughly a 1,570m/s deficit to GEO. That's almost Zenit-3SL/Proton-M/Briz-M performance.Just a question about your sign convention: how can the DEFICIT to GEO be this large, when this mission used a super-synchronous transfer orbit? It would seem to have a significantly smaller deficit, since the semi-major axis is much closer to GEO than a standard Hohmann GTO, or indeed, even the S/C separation orbit of a Briz-M for a payload of equal mass... isn't the energy of the orbit a function of semi-major axis?
Quote from: Targeteer on 05/16/2017 04:20 pm42698 INMARSAT 5-F4 2017-025A 1401.67min 24.50deg 69839km 381km 42699 FALCON 9 R/B 2017-025B 1410.43min 24.47deg 70181km 384kmRoughly a 1,570m/s deficit to GEO. That's almost Zenit-3SL/Proton-M/Briz-M performance.
42698 INMARSAT 5-F4 2017-025A 1401.67min 24.50deg 69839km 381km 42699 FALCON 9 R/B 2017-025B 1410.43min 24.47deg 70181km 384km
Quote from: baldusi on 05/17/2017 01:56 pm...Zenit-3SL can do 6.16 to a 1,477m/s deficit GTO. That's a ~95m/s difference. If they used less delta-v GTO, and they didn't had structural limits on the rocket, it would be much higher performance. Using a linear approximation I get 7.8 tonnes.Isn't Zenit retired or on last launch?
May I ask how high an apogee would this launch have produced if it did zero inclination reduction ?Perhaps this will better explain to people how significant this performance was, considering it was also the heaviest F9 GTO payload to date !
Here's how I was finally able to get my mind around this launch result. It would take an Atlas 541 to match this performance, or a Proton M Briz M Phase 3 or 4. Ariane 5 ECA could do it, of course, as could Delta 4 Heavy. CZ-5, theoretically though it has yet to demonstrate the capability. H-2B, ditto. That's it, I think, among active launchers.Delta 4 Mediums can't do this at all. Neither can H-2A, or CZ-3B, or CZ-7, or GSLV Mk 3. When Falcon 9 first began flying, I thought of it as slightly better than Delta 2 class. The machine has evolved, and the most recent two flights have exhibited a new level of performance - to the extent that I'm convinced we are seeing at least a Block 4 second stage. - Ed Kyle
May I ask how high an apogee would this launch have produced if it did zero inclination reduction ?
Perhaps Chris can give away a free L2 subscription to the 1st person that can identify which of the preceeding 12 isn't like the others.
Quote from: AC in NC on 05/17/2017 08:07 pmPerhaps Chris can give away a free L2 subscription to the 1st person that can identify which of the preceeding 12 isn't like the others.Hmm... I was going to say they all have strap on boosters (Solid or liquid) except for Proton and F9. Is it that the Proton is a 4 stage rocket? I don't think any of the others are.
Quote from: macpacheco on 05/17/2017 04:42 pmMay I ask how high an apogee would this launch have produced if it did zero inclination reduction ?Perhaps this will better explain to people how significant this performance was, considering it was also the heaviest F9 GTO payload to date !The problem with orbital mechanics is that mixing apogee increase AND plane change is a lot cheaper than doing one and then the other one. I will yield to Lou to do such calculation, though.
The machine has evolved, and the most recent two flights have exhibited a new level of performance - to the extent that I'm convinced we are seeing at least a Block 4 second stage.
Quote from: baldusi on 05/17/2017 07:42 pmQuote from: macpacheco on 05/17/2017 04:42 pmMay I ask how high an apogee would this launch have produced if it did zero inclination reduction ?Perhaps this will better explain to people how significant this performance was, considering it was also the heaviest F9 GTO payload to date !The problem with orbital mechanics is that mixing apogee increase AND plane change is a lot cheaper than doing one and then the other one. I will yield to Lou to do such calculation, though.I thought that the best usage of LV performance was to put the GTO payload on as high as possible apogee, and THEN once its on a super sync trajectory, it can use the lower speeds of the apogee to effect some inclination change and reduction in apogee on each orbital apogee and increase in perigee on each orbital perigee, done by the payload itself.That led me to think that if SpaceX could create a mini ITS rocket that had perhaps 5+ days of mission endurance, it could do a bi elliptical transfer by itself, by going into a super sync orbit, doing the entire inclination change and apogee reduction in a single burn, then the perigee raising in the other half orbit and deliver a large number of GEO payloads into GEO-500m/s with zero inclination and just some circularization left, so the orbital period is a few hours away from GEO, so the payloads can pace themselves to go directly into their exact slots, although they would all be delivered to the same initial orbit.The mini ITS would then do the required orbital transfer to re-enter and land, avoiding brute force trajectory corrections to get to the LZ.
Quote from: edkyle99 on 05/17/2017 06:15 pmThe machine has evolved, and the most recent two flights have exhibited a new level of performance - to the extent that I'm convinced we are seeing at least a Block 4 second stage.Not sure about two latest flights, but the last one was totally out of family. Looks like a different rocket.
Perhaps now I actually understand why people are so reluctant to even entertain the possibility that F9 expendable with zero margins might be able to put an 8.3 ton payload in GTO-1800 m/s. That would challenge every rocket in service, except for Ariane V and D4H.It really must be hard to conceive that such a cheap rocket can get that much performance. But I'm a believer, eventually there will be one Block V expendable launch that will place something like a 7.5 ton payload to an orbit similar to this, and awe the world ! A payload large enough that in requires the same effort to put that 8.3 tons to GTO-1800 !