This is the diary of Iridia Enasteriou, OxidanSky’s Chief Satellite Operations Officer, covering her observations of Launch 4 of ten Iridium NEXT satellites. Iridium Communications is the world’s only truly global mobile satellite communications company, which Iridia is a great fan of – category “maniac”. Iridium Communications are currently replacing all of their legacy satellites in the greatest tech upgrade ever. They are putting 66 satellites into mission and 9 spares into orbit.
- Actual dates/times of satellite maneuvers can differ slightly from the ones stated here due to a time lag between TLEs and site updates.
- Technically, not everything is related to Launch 4, e.g. some de-orbits or re-entries or drifting satellites are actually from previous launches.
- Featured image: © and courtesy of Iridium Communications.
- OxidanSky is in no way affiliated with or representing Iridium Communications.
Dec 22, 2017
The day of/before Launch 4. I don’t know what to call it when the launch happens on different days as far as time-zones are concerned. I’m already incredibly excited and looking forward to it like crazy. Nonetheless, I’ve taken a tough decision: I will not stay awake for the launch, but rather try to sleep. I’m telling myself that I don’t see it „live“ either way and that it doesn’t make a difference at what time I watch the webcast. It feels like a huge sacrifice, but hey – my sleep pattern now has to be first priority.
Dec 23, 2017
Oh maaaan, what a commotion!
I dutifully went to bed and was even able to fall asleep. When I woke up, I thought it was in the morning, the launch had already happened and I would watch it over breakfast. I looked at my phone and saw it was not morning, but night. So I figured, why not look into the webcast … And there it was: I had woken up and tuned into the webcast the very moment that it started. So I said to myself: This is a sign, I must watch the live cast 🙂
The webcast itself was great, but what caught my attention was that John Insprucker mentioned something about a frenzy on social media. So I got into that and couldn’t believe the images that I saw and people’s reactions and all. It was unbelievable! I got so hyped up that I couldn’t fall asleep again. I watched all the videos I could find from people in their cars, praying because of … aliens, nuclear missile attacks, UFOs, conspiracy stuff … It was just unbelievable. And the images got better and better, soon the quality stuff started arriving and being discussed. I saw clear imagery of the fairing thrusters and the interactions between the plumes of thrusters and the two stages. Phenomenal!
I was completely off-rail for the rest of the day, posting and firing like crazy on all my social media channels. It totally got to me. I later installed one of the best pictures of the “spacefish“ as my lockscreen saver. My phone has looked incredibly elegant ever since.
On top of it, SV 6 re-entered after a recreational week in parking orbit and a de-orbit phase of just three weeks. Another one gone! SV 6 was particularly dear to us due to the rare opportunities of double flares that it had offered. For some time, it was paired with SV 51. Both of them were only partially operating, but as a team they were fully functional. They were positioned just a few seconds apart from each other and therefore flared together. An event that went largely unnoticed – even by me for quite some time for the following reason: SV 51 was listed as a spare satellite. Most flare apps do not consider spares in their flare notifications. One of the apps I use is iFlares which does show what it calls reserve satellites. I had this option de-activated most of the time, though. But not so on the evening of July 30, 2016 and it sprung to my eyes that something was cooking. And soon afterwards I got my mind completely blown. SV 6 flared just beautifully with a -7.6 mag towards the Northern summer skies, tailed at not even a finger’s distance by SV 51. Next evening, I was lucky enough to see another of these double flares, albeit not with such a great magnitude. A friend of mine topped everything: He had started flare-watching only a couple of days earlier and managed to see SVs 6 and 51 as daytime flares with a -8.0 mag! How exceptional is that?! I got lucky again on Apr 25, 2017 with SV 6 flaring at -8.1 mag. This time within heavily light-polluted city confines. Nonetheless, we managed to capture it on smartphone video. Faint, but a lovely document of a pleasure that is not going to come back.
And later in the day, the TLEs for Launch 4 came out. I was so happy about the fact that I could start my observations so soon. What a beautiful, miraculous, wonderful day!
Dec 24, 2017
That’s fantastic! The identification of the SVs is already out. So I can start working my lists for the individual satellites and monitor their TLEs and orbits throughout their journey to service. In case you might want to know, Celestrak is my source for the TLEs.
Yes, indeed, I’m surprised myself about what makes me incredibly happy.
Dec 25, 2017
Well, it’s Christmas. The sats are probably doing some Christmassy stuff, as well as their operators. Bless them!
Dec 26, 2017
Still Christmas, so I guess that’s okay.
Dec 27, 2017
I know they are testing the bus, but what exactly does that mean? Do they fire the thrusters to see if they really work?
Dec 28, 2017
Dec 29, 2017
Finally some movement! SV 134 has started its ascent to storage orbit. Yay! How do I know? I can tell from the TLEs. Changes in inclination, eccentricity and revs per day.
Dec 30, 2017
So we get going! SV 134 arrives in storage orbit.
SV 130 begins ascent to storage orbit.
Dec 31, 2017
Boring! But hey, it’s New Year’s Eve, so that’s kind of okay.
Jan 1, 2018
SV 130 arrives in storage orbit. How do I know? I check it out at the fantastic Stuffin.space website! It not only visualizes all the satellites, but gives you their apogees and perigees and other useful information. It only updates once a day, though, so in reality things happen a bit earlier than the time stamp that I give them here 🙂
Jan 2, 2018
Now we’re talking business! Fast succession of orbital maneuvers! SV 131 arrives in storage orbit, SV 135 starts ascent to storage orbit.
Jan 3, 2018
Nothing really going on, but I can tell that SV 151 is buckling up its laces to shoot up to storage orbit.
Whoa, Satflare is announcing that SV 37 is de-orbiting, with a re-entry date on Jan 16. Whaaat? No way! All the data point to it being peacefully in parking orbit. I don’t buy it, Satflare!
Jan 4, 2018
SV 151 is ascending to storage orbit.
SV 37 is still in Satflare’s de-orbiting schedule. May I just call this outright crazy?
Jan 5, 2018
SV 135 arrives in storage orbit. Congrats to whoever!
I was reflecting a bit on how I actually proceed in my observations. I started from scratch with Launch 1 and had absolutely no clue what even to look for. I just collected data in a rather wild and uncoordinated form, printed out heaps of TLEs etc. Launch 2 already saw me with printed forms, but still very unclear about what the relevant data actually were. When I noticed that something was missing, I started scribbling it chaotically on my forms. Launch 3 was already quite good, with only a few inconveniences due to columns not in line with the TLE order. But that was a minor issue. I had, by then, already got a fairly good grasp of recurring patterns. So that’s the thing: Pattern recognition is my main method of working and basically the only one available to me, since I have no tech or science background.
Jan 6, 2018
SV 138 started its ascent to storage orbit, SV 151 reaches storage orbit, SV 134 starts ascent to mission orbit.
Futher news: SV 153 starts drifting to Plane 1. I got this one very quickly by noticing its decline in inclination.
Jan 7, 2018
SV 134 starts ascent to mission orbit – the first one to venture out that far.
Jan 8, 2018
SV 131 is now ascending to mission orbit, SV 116 started ascent to storage orbit.
And some reason for a loud boohoo! SV 34 re-entered today which is exciting, yet it makes me sad, too. Another one gone! I had only seen SV 34 twice, in 2012 and 2014. The second time round was particularly beautiful, the notes in our Iridium flare bingo talk about it like this: “The flare opened like a bud, a shiny and spherical flower”. Miss you, SV 34!
What I find really bizarre: @IridiumComm’s de-orbit message had many likes on Twitter. Why do people like it when one of their favorite sats comes down?
What I found a bit off: @IridiumComm posted a retirement pic of SV 34 with a fishing rod, talking about the sat retiring in the atmosphere. IMHO this is a wrong metaphor, because it has no factual backing and is rather misleading. I don’t think it’s particularly funny either, but I appreciate their creative approach. They often put things in a humorous context, which is great.
And it feels quite kindred-spirited to me and my video animations in particular. When SV 77 was about to re-enter, I felt the urge to make another video. It’s just a tiny one, rather sloppy in comparison to the others, and with very little detail. It also contains some totally untenable premises (like sats meeting in orbit for a quick chat), but it was important to me to make a clear difference between a satellite retired in a parking orbit and a bird re-entering and burning up in the atmosphere.
Jan 9, 2018
SV 134 reaches mission orbit, SV 141 is not on ascent to storage orbit.
Jan 10, 2018
SV 116 reaches storage orbit, SV 135 started ascent to mission orbit, SV 131 reaches mission orbit. Gee, very factual entries today.
Jan 11, 2018
SV 137 started ascent to storage orbit, SV 141 reaches storage orbit, SV 130 began its ascent to mission orbit.
There’s some craziness going on in the data of SV 135. It seems to have started ascent to mission orbit yesterday, an elevation in orbit is visible today, but the inclination has switched back and forth, which does not make any sense. The data must somehow be wrong. Or something is going on that I have not yet come across and simply have no clue about.
Jan 12, 2018
How batshit crazy is this? I’ve seen SV 37 in the re-entry list on Satflare for such a long time, scheduled for Jan 16, 2018 – obviously completely wrong. But maybe Iridium had given early notification to JSpOC and somehow the re-entry date was keyed in or calculated wrongly? Because: SV 37 has begun its de-orbit! It’s still listed as re-entering on Jan 16, which obviously won’t be the case. Let’s see when Staflare will rectify it.
SVs 131 and 134 have been put into service. Wow, the first ones from this launch! Why do I know that? Easy: @IridiumBoss announced it on Twitter.
It all seems to go so fast and so slow at the same time.
SV 135’s data are back to the level of Jan 9, 2018. They must have imported the wrong data the other day. Or it’s me being completely ignorant of I don’t even know what 🙂 Full-blown ignorance, that is.
Jan 13, 2018
SV 130 reaches mission orbit, SV 137 reaches storage orbit. Check!
Hey, why haven’t I realized this earlier? When a sat is in its proper place and orbit, its argument of perigee has to be approximately 90 degrees. It’s at the apsides (which I know for Iridium sats to be over the poles) that the sats are so tightly packed together that many of them are briefly taken offline, receiving software updates, minor course corrections etc. I can’t believe it took me that long to come to this conclusion.
Jan 14, 2018
Jan 15, 2018
SV 138 is nearly there, I can already guess it will swap with SV 49. My way of observing the positions of the sats relative to each other as well as in their distinct orbits even allows me to guess quite accurately which of the Block 1 sats will be targeted for the slot swap. It took me a while to develop this system and I’m constantly improving it. I’ve come up with a colour code that gives me a good overview of the status of each satellite as well a visual reference of when a maneuver was started.
Jan 16, 2018
SV 138 reached mission orbit.
Satflare finally realized that SV 37 will not re-enter today. They set the new re-entry date to Dec 31, 2018. Which seems quite arbitrary to me. I guess they cannot display re-entry dates past year-end, so they simply put that date as a placeholder for later dates or everything they don’t yet know.
Jan 17, 2018
Jan 18, 2018
Jan 19, 2017
SV 151 started its ascent to mission orbit.
@IridiumBoss said SVs 131 and 138 were put in service on Jan 17, 2018.
I’m trying to figure out whether the service swap can be deducted from the data in any form. But I haven’t found any cogent evidence yet, and I haven’t got sufficient data from past slot swaps. With every launch I find out new stuff. In the beginning, I didn’t even know what to look for, what data to collect. Meanwhile I’ve become quite good at that as well as at organizing my data. Which makes it more fun, obviously.
Jan 21, 2018
Damn! I hate it when I make this little mistakes that cut me off from interesting findings. Yesterday I somehow forgot to take down the data of SV 3. And guess what? Its de-orbit process has started! Wish I could see yesterday’s TLEs to find out when and how the de-orbit process started.
SV 135 is ascending to mission orbit.
Jan 22, 2018
SV 151 has already reached mission orbit and will swap with SV 46.
Ha, the date of Launch 5 has finally been officially confirmed. In a very odd way, I have to say: @IridiumComm via official press release, but, uhm, taking their time. @IridiumBoss announced it very swiftly by retweeting someone else’s (a journalist, if I remember correctly) statement.
Jan 23, 2018
Strange that no gain in orbit altitude was reported as compared to previous day. Sometimes the data don’t make sense at all, sorry guys!
Jan 24, 2018
SV 135 has made it to mission orbit, swapping with SV 23. Good old 23! It took us five years to finally see SV 23 flare – the last one in our Iridium flare bingo. We were so lucky to catch it before its demise.
SV 116 started its climb up to mission orbit. Yay!
Jan 25, 2018
SV 49 starts the de-orbit process. Wow, particularly the de-orbits are happening very fast these days. So far, no sats have been put into parking orbit.
SVs 135 and 151 have already been put in service. They now swap so quickly, it’s awesome!
Jan 26, 2018
SV 116 is nearly home, going to swap with SV 25.
It’s only today that Satflare has come up with a serious re-entry date for SV 37: May 3, 2018. I still can’t make any sense of what had been going on with them over the last weeks.
Jan 27, 2018
SV 116 has reached mission orbit. Good boy!
SV 137 has started its way up, up, up! The sky won’t be the limit for the little chap, but mission orbit might be.
Jan 28, 2018
SV 137 has reached mission orbit, soon kicking SV 76 out of the old boys’ club.
SV 141 has started ascent to mission orbit. The last Launch-4 critter to take the uphill journey!
Jan 29, 2018
SV 141 is still on ascent, and I can affirm my assumption of yesterday that it will replace SV 94. Ah, it seems I did not write that down. Well, never mind …
So now the storage orbit is completely empty and by tomorrow all sats will have reached mission orbit.
Jan 30, 2018
@IridiumBoss confirms that SVs 116 and 137 have already been put in service and that SV 141 will go tomorrow.
SV 141 is nearly there, but not quite yet (well, it is, but I can’t yet see it in the apsides displayed on Stuffin.space due to its update lag).
And another exciting piece of news from Matt Desch: The first drifters will be coming in soon. I had not had them on my radar recently because so much other stuff was going on. So it’s about time to get organized and start observing. I figure it would take SVs 105 and 108 app. 22 days to arrive in Plane 5. Why that? When they first started drifting, I compared their daily change of RAAN to that of the other sats and noticed a difference of roughly 0.11 degrees per day.
Jan 31, 2018
This is obviously the day to pop the champagne: All Launch-4 satellites have been put in service! Another great achievement, fast and effortless, or so it seems for the distant observer. I’m very happy for the folks at Iridium. They must feel so proud and excited at the progress they’re making. And probably over-worked 🙂
Feb 1, 2018
Now that the chunky bits are done, I can only look for de-orbits or sats being pushed to a parking orbit. What puzzles me: SV 11 seems to be elevated. WTF?
Feb 2, 2018
SV 11 has indeed been elevated to an orbit even higher than mission orbit. Why is that? I wonder whether, similar to SV 97, SV 11 will be lowered again and inserted into mission orbit at a different spot, that could be either in front of SV 47 or 20 (they have not yet been replaced and are pretty old). I guess I’ll know by tomorrow.
Feb 3, 2018
SV 11 keeps being rather mysterious. As I had expected, it was lowered back into mission orbit, but not to back up any of the two legacy satellites. Instead it is now breathing down the neck of SV 134. I have no idea why this could be the case. I counter-checked my conclusions with Rod Sladen’s page on the status of the Iridium constellation. The site is a treasure trove, it shows all the changes that have ever, it seems, been made to the constellation. Rod came to the same conclusion. Hope there will be some update on this issue soon, because my mind wants to understand. Everything.
Feb 4, 2018
No news about SV 11, it’s still hugging up to SV 134.
But SV 43 has showed up in the re-entry table for the first time. It’s a little stinging pain every time. Another one to go down soon, another one that will flare no more. At the same time I’m glad that they can de-orbit so many sats so swiftly. We all don’t want space debris flying around our ears forever, right?
Feb 5, 2018
I got a great answer from @IridiumBoss on the SV 11 question. “It’s co-located and linked into/through SV 134 while the team runs some software tests on that satellite. It will handle K-band traffic for SV 134 during the special testing to ensure there is no customer disruption.” Amazing how they move their space furniture around like toy cars to do awesome stuff. @IridiumBoss adds: “Frankly, I think my ops team is just showing off now…” Mission of showing off accomplished, I am thoroughly impressed by what they can do. And if showing off is linked to a purpose, that’s quite something 😉
Well, that’s more or less it for L-4. All sats in place and in service. Maybe there’ll be the occasional de-orbit or descent into a parking orbit. And, of course, I’ll keep track of the on-going de-orbits.
Feb 7, 2018
There’s something going on with SV 46. I’m not yet sure whether it has started its de-orbit or will be placed into a storage orbit as a spare until the constellation is complete. From the TLE’s, I tend towards parking orbit, but it’s too early to tell. Plus I haven’t seen any sats put into parking in Plane 2. Maybe Iridium doesn’t do that any more?
Feb 8, 2018
Another #Flarewell day with those mixed feelings. SV 03 is – and has made – history. I’ve seen it nine times between 2012 and 2017. It was one of my first flare sightings, a beautiful -5.7 mag. I managed to catch it out of the window of my living room and described it as “comet-like”. It seemed to leave an iridescent trail behind and was just beautiful. That’s why I gave it a 9 on our flaregasm scale (which actually only ranges from 0 to 7). A couple of weeks later, it graced me again with a modest -1.3 mag. The calculation provided by the app was probably inaccurate, since the flare was incredibly bright and lasted very long. Another one that broke the meter: 8 out of 7 on the flaregasm scale. Flarewell, little fella, you’ll be truly missed!
SV 46 hasn’t taken a sharp plunge, so most likely not a de-orbit.
Feb 9, 2018
And SV 46 is now clearly de-orbiting. TLEs came in sluggishly yesterday, that’s why I couldn’t be sure for quite some time.
Feb 10, 2018
Whoa, they’re clearing out the orbit as if it were a summer-end sale! SV 25 is descending to parking orbit, hopefully enjoying retirement.
SV 23 has also embarked onto its final journey. Remember, it’s the one that took five years to finally let us see it flare. That’s why it has somehow achieved a special status. I’m particularly sad to see it go, but also happy that we managed to see it – not very last minute, but quite close.
Feb 11, 2018
Today marks the day when SV 43 called it quits. After a 9 month’s downward plunge, it must have experienced quite a sizzle. I had seen it three times, no special anecdotes this time. #Flarewell, mate!
Feb 13, 2018
Another day to say #Flarewell … SV 49 re-entered today. I have no specific memories of it. I saw it twice, but both times it was very faint and basically didn’t flare.
Feb 19, 2018
No TLE update for SV 108, one of the Launch 1 sats drifting to Plane 5. This could be a hint that it’s being raised to mission orbit. Let’s see how it’s going to play out!
Feb 20, 2018
Caramba! SV 108’s orbital elements have changed and it has been raised to 656/653. SV 105 still looked unsuspicious yesterday, but today it’s obvious that it is going through the same drill: Orbit raised to 656/648.
I’m so excited to find out how they do the slot-swaps for the drifters. Probably no different to all the others, but still … it’s a first and that always triggers my curiosity.
Feb 22, 2018
I think SVs 105 and 108 did another burn to raise their orbits to around 710/705 km.
Feb 24, 2018
Next maneuver for SVs 105 and 108, they’re currently at approximately 760/750 km.
Feb 28, 2018
Mar 2, 2018
Holy cow, SV 94 is being de-orbited! It had been such a darling! It served as demonstration object when I wanted to show an Iridium flare to a colleague. We had been trying to find an evening on which we were both free, there was a flare and good viewing conditions. 94 did not knock us off completely, but my friend got to see the excitement and how it all goes down.
On a different occasion, I saw SV 94 as a daytime flare. It was a –8.0 mag and I saw it like a light that was switched on just for a fraction of a second. One of the very few daytimers I saw.
Mar 5, 2018
There has obviously been some testing going on and today SVs 105 and 108 have gone into service. High time to start observing SVs 12 and 13, their slot-swap partners and see what will happen to them.
OMG, time passes so quickly that I totally overlooked the other drifters: @IridiumBoss tweeted today that three of them would be put into service before Launch 5. I know who they are, but I would have thought them to still be way down the line.
That’s actually a pity, because SV 128 has already been raised to mission orbit altitude while still drifting – and I don’t know how and when! While SVs 120 and 113 are still drifting at their insertion altitude. Drifting east or west seems to be an entirely different process and I missed out on part of it. Darn!
Mar 8, 2018
Time to start saying good-bye to another bird: SV 90 has been sent on its final journey. It’s another one particularly dear to me: I saw it in a double flare together with SV 50. One of my first sightings, together with Freya. We totally freaked out when we saw those two sats lined up. Despite bad viewing conditions (a bright street light in the middle of nowhere on Crete) and someone turning on the lights on a balcony two seconds before the sats flared, blinding and infuriating us. Nonetheless, we saw them well and they made us very happy.
And then, SV 97 is finally taken out of mission orbit and put into storage orbit. I assume it was involved in some kind of test just like SV 11 because it had been put to a different slot in mission orbit after its replacement with a NEXT satellite.
Mar 10, 2018
The fun part is now starting for SV 120. Its orbit is being raised, its eccentricity is down drastically from yesterday. I realized that I make very weird sounds whenever I notice a sat being maneuvered. This must scare the shit out of the cat that I don’t have.
And another reason to holler: SV 76 has finally been shoved to storage orbit. I was surprised that it had been hanging around with the new lads in mission orbit for such a long time. Well, I hope they have said their farewells and had one for the road for the very last time.
Mar 18, 2018
SV 120 has nearly made it! I guess by tomorrow its orbital data should be where they are supposed to be for being put into mission. From what I see, I expect the slow-swap partner to be SV 47.
SV 113 is lagging slightly behind, I’d estimate a day or two, but it should very soon reach mission orbit as well.
I’m still wondering whether SVs 22 and 11 will be hanging around forever. Maybe they just refuse to go 🙂
Mar 19, 2018
SV 120 has arrived at mission altitude, I guess it will still see a slight reduction in argument of perigee and it is definitely swapping with SV 47. SV 113 is catching up big time, should arrive at the proper orbit tomorrow – to make another wild assumption that might totally ridicule itself in a couple of hours.
Wow, SV 94 seems in a hurry to re-enter. According to SatFlare, it’s supposed to fire-dive on March 29 and would thus squeeze itself between Thelma and Louise. How dare it!
Mar 20, 2018
No. And yes.
SV 94 is showing some respect to Thelma and Louise and is holding back its demise for another month. What a gent!
I’ve come up with two theories:
- It takes these predictors some time after a de-orbit has begun to figure out what is actually going on.
- There seem to be days with either all orbital actuaries completely hung over (that’s not the theory) or some kind of “drag weather”. On those days, most satellites are attributed with an extremely early or late re-entry date compared to the previous days. Usually everything is back to normal the next day.
Mar 21, 2018
Everyone is being good and well-behaved.
Mar 23, 2018
Finally SV 12 is being removed from mission orbit. As things look at the moment, I guess it will be put into storage orbit to act as a spare. Plane 5 will only be targeted by Launch-7, so that’s still a while.
And as soon as I had pressed “save”, Matt Desch tweeted out that SVs 113 an 120 had been put into service.
Mar 28, 2018
Interesting: Although SV 113 was put into service several days ago, it seems that it was only now put into its “proper” place: Its eccentricity has been reduced , thus slightly lowering the apogee to 783 km, hand in hand with a drop in argument of perigee to some 88 deg.
Mar 29, 2018
Same thing, different data today for SV 120. And, very confusing, yesterday’s changes to SV 113 seem to have been more or less undone. Man, it’s really rocket science … !
Apr 23, 2018
While I was busy shooting rockets into the sky, SV 25 was put on its final path towards re-entry. Another dear one – I saw it seven times, the last time not even two weeks ago. And on one occasion it flared extremely strong and very long, it was a flare from one of its solar panels!
Apr 26, 2018
Busy activity in Plane 2 these days: SV 11, the one with the wayfaring history, has been retired into parking orbit.
May 7, 2018
Now it has been SV 47’s turn to fully retire into parking orbit and serve as a spare. Ya never know, just in case …
May 14, 2018
Another satellite that we will never see again: SV 25 re-entered today over the Pacific Ocean, west of Peru. Seven times I was graced with flares by that sat, what a bounty of glint! The first time was pretty spectacular: I was simply stargazing and noticed some satellite quietly doing its laps. While I followed it without any expectations, all of a sudden something crossed its path and flared. What a lovely surprise! My research showed it was Iridium 25. The second time was also interesting because it was not a flare from the main mission antenna, but from one of the solar panels. It lasted particularly long and I gave it a 7 (out of 7) on the flaregasm scale. Flarewell SV 25, and thanks for the lovely surprises. You’ll be missed!