Regarding the decay of Stage 2: The perigee height won't stay there for long. It will be perturbed higher or lower by the Moon etc. when nearer to apogee. This should be even more marker on a super-synchronous transfer orbit. Next question being, which way will it be perturbed and by how much...?
It is left as an exercise for the reader to figure out which ones have decayed and any typos.
This thread is drifting from discussing the May 15 Inmarsat 5 F4 launch. These are interesting enough topics but there are dedicated threads for them elsewhere. (I would love to see a single plot of the second stage apogee heights vs calendar days, but except for THIS second stage, it would go in a general discussion thread.)
Quote from: input~2 on 05/18/2017 07:07 pmQuote from: BabaORileyUSA on 05/16/2017 05:08 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 384kmI believe these are identified backwards: the payload is in the 384 x 70,181 km orbit; and the Falcon-9 upper stage rocket body is in the 381 x 69,839 km orbit. Expect 18 SPCS to swap these in the next couple of days.Swap has taken place:42698 INMARSAT 5-F4 2017-025A 1409.24 min 24.52deg 70134km 385km42699 FALCON 9 R/B 2017-025B 1401.51 min 24.47deg 69835km 378kmStill no maneuvers detected...
Quote from: BabaORileyUSA on 05/16/2017 05:08 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 384kmI believe these are identified backwards: the payload is in the 384 x 70,181 km orbit; and the Falcon-9 upper stage rocket body is in the 381 x 69,839 km orbit. Expect 18 SPCS to swap these in the next couple of days.Swap has taken place:42698 INMARSAT 5-F4 2017-025A 1409.24 min 24.52deg 70134km 385km42699 FALCON 9 R/B 2017-025B 1401.51 min 24.47deg 69835km 378km
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 384kmI believe these are identified backwards: the payload is in the 384 x 70,181 km orbit; and the Falcon-9 upper stage rocket body is in the 381 x 69,839 km orbit. Expect 18 SPCS to swap these in the next couple of days.
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: Targeteer on 05/23/2017 12:55 amQuote from: input~2 on 05/18/2017 07:07 pmQuote from: BabaORileyUSA on 05/16/2017 05:08 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 384kmI believe these are identified backwards: the payload is in the 384 x 70,181 km orbit; and the Falcon-9 upper stage rocket body is in the 381 x 69,839 km orbit. Expect 18 SPCS to swap these in the next couple of days.Swap has taken place:42698 INMARSAT 5-F4 2017-025A 1409.24 min 24.52deg 70134km 385km42699 FALCON 9 R/B 2017-025B 1401.51 min 24.47deg 69835km 378kmStill no maneuvers detected...Would those be explained by timing so that once they start their burns they get to the right GEO slot, and right now with each orbit the get closer to that proper timing faster than if they did some substantial burns prior ?
I dont think so. With two burns, one that parks perigee somewhere between where it is now and GEO height and an other one for the final perigee raise they can get to almost any point within 2 or 3 orbits. By now, they must have at least 10 orbits.
Quote from: Semmel on 05/23/2017 09:02 amI dont think so. With two burns, one that parks perigee somewhere between where it is now and GEO height and an other one for the final perigee raise they can get to almost any point within 2 or 3 orbits. By now, they must have at least 10 orbits.The satellite is supposed to be a spare. Would it make sense to leave it in the current transfer orbit until it is actually needed?
Quote from: jpo234 on 05/23/2017 10:25 amQuote from: Semmel on 05/23/2017 09:02 amI dont think so. With two burns, one that parks perigee somewhere between where it is now and GEO height and an other one for the final perigee raise they can get to almost any point within 2 or 3 orbits. By now, they must have at least 10 orbits.The satellite is supposed to be a spare. Would it make sense to leave it in the current transfer orbit until it is actually needed?Generally, I was under the impression this is a bad idea due to the repeated transits through the Van Allen belts. Those tend to be hard on satellite electronics. My wager is that the satellite checkout is continuing in some form and that they will start the orbital changes as soon as they are satisfied. I'm sure they can use it to decongest bandwidth in their high demand areas (europe was mentioned before). Also, AFAIK it's actually not that energetically expensive to change orbital slots in GSO since you can do a racetrack maneuver or something similar. Just raise or lower your orbit by a few km, drift till you get to the correct slot and re-enter. Low total dV expenditure.
Not energetically expensive, but how long it would take to go half way around the globe that way ? How many months ? Timing can be very important in several situations.
Quote from: jpo234 on 05/23/2017 10:25 amQuote from: Semmel on 05/23/2017 09:02 amI dont think so. With two burns, one that parks perigee somewhere between where it is now and GEO height and an other one for the final perigee raise they can get to almost any point within 2 or 3 orbits. By now, they must have at least 10 orbits.The satellite is supposed to be a spare. Would it make sense to leave it in the current transfer orbit until it is actually needed?They will probably have to go to Geo to check out the satellite before the manufacturer hands it over to the customer. You aren't going to be verifying link budgets and channel performance in GTO.
Tweeted, but when I went to RT, it said action unavailable and that's because they deleted it.....sorry, which I could have grabbed the pics, but at least screenshot the deleted tweet. Oh, they deleted it because they typoed. Proton 9 Anyway, they haven't tweeted the correction.....we get the message and the milestone.
To be fair - and assuming this campaign did do a depletion burn as theorized - this was a 531/4M+5,4 performance (see the WGS campaigns for Delta IV and the AEHF campaigns for Atlas V). It is assumed that Block 5 may match 541, while still being a two stage kerolox LV (and about 20t heavier than said Atlas V variant).
You are referring to high energy orbits, right?To LEO, Block 5 will far surpass Atlas V 551; may come close to matching Delta IV Heavy.