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Scott Tilley 🇺🇦 Profile picture
Scott Tilley 🇺🇦
@coastal8049
New content is no longer posted here. See 🦋 for my latest posts. Thanks!
Dec 22, 2023 • 8 tweets • 3 min read
Update on the Chinese 'spaceplane' monitoring effort. @plugger_lockett observed possible emissions from objects from the 2023-195 launch. Despite using the same modulations it turns out these emissions are from other secret Chinese military sats, raising more questions. 🧵⬇️ Upon fixing a minor timing issue with his ground station @plugger_lockett sent me data from a pass yesterday & I was able to determine that the object being tracked yesterday was in fact YAOGAN-30 X the track of which passed over one of 2023-195. ⬇️ Image
Aug 19, 2023 • 8 tweets • 2 min read
Moon rise here at the station. As the Moon clears the trees, an "Emergency" was declared by @roscosmos for #Luna25 as it failed to perform an orbital adjustment burn. Lets discuss how this could affect the mission. 🧵⬇️ Image A telegram post by @roscosmos provides limited information of the status of #Luna25. Apparently, the spacecraft failed to adjust its orbit as planned.⬇️ https://t.me/roscosmos_gk/10535
Aug 13, 2023 • 10 tweets • 3 min read
I have been asked repeatedly about #Luna25.

Thus far I have no independent observations of the mission to share. That is not without extensive trying to observe it.

So why am I not detecting anything? 🧵⬇️ Image #Luna25 was launched into a trajectory that is largely only visible on Earth in daylight. Secondly, that trajectory is not exactly known. I have calculated one based on the launch timing and the scant public info shared and used GMAT to find a good direct trajectory. ⬇️ Image
Aug 13, 2023 • 6 tweets • 1 min read
A follower asked if #Chandrayaan3 could land on the Moon before #Luna25. The short answer is maybe.

As we'll see in this thread changing a plan as complex as landing on the Moon is not a great idea.🧵⬇️ #Chandrayaan3 is presently largely locked into an orbital plane above the Moon. What that means is that it needs to wait for the Moon to rotate under-neigh it to reach the primary landing site that @isro has painstakingly planned to land at. ⬇️
Aug 3, 2023 • 4 tweets • 1 min read
#Chandrayaan3 trajectory update 2023-08-02 #2.

Despite my better judgement, I did a TLE update on the Doppler data. The problem with TLEs in these types of orbits is they degenerate fast as the model is not designed to deal with long periods et. al. 🧵⬇️
Image
Image Small changes in the data or the fit has profound effects on the TLE and the orbital model. But they are convenient. So I offer a couple of TLEs to aid anyone wishing to hunt for #Chandrayaan3. NO WARRANTY offered 😉, look with WIDE field... ⬇️
Jan 12, 2023 • 13 tweets • 6 min read
I've recently renewed an observing campaign on #TIANWEN1. The orbit hasn't changed so an aerobrake test claimed for late 2022 has not occurred yet. In preparation for observing an aerobraking manoeuvre I thought it would be interesting to study past missions that did one. 🧵⬇️ By NASA/JPL/Corby Waste - https://solarsystem.nasa.gov/multi First a bit a reference of why we believe #TIANWEN1 will conduct an aerobraking test. This all relates to the #TIANWEN3 Mars sample return mission.
spacenews.com/china-aims-to-…
Jan 10, 2023 • 5 tweets • 3 min read
#TIANWEN1 orbit remains unchanged based on period measurements.
T=25482s,
a=8898km. So no aerobrake test yet.

Neuquén ground station apparently attempted to lock to the spacecraft last night and failed. News reports of orbiter having communications issues. 🧵⬇️ ImageImage This zoomed in Doppler plot of #TIANWEN1's signal during the anomalous lock attempt from yesterday is depicted below. Neuquén ground station appears to be using uplink Doppler compensation but is out of sync with the actual orbit of the spacecraft. ⬇️ Neuquén ground station in A...
Nov 13, 2022 • 4 tweets • 1 min read
The R/B of the Yunhai 1-03 mission appears to have suffered a breakup event. The plane of the orbit is nicely visible in the evening in the Northern hemisphere. Observers could look for debris by observing along the R/B plane and looking early.
OBJECT B [54236, 2022-151B] 🧵 The irony is the satellite Yunhai 1-03 is replacing was itself hit by another satellite. Goes to show you that space junk at these orbital altitudes is not a good thing.
space.com/china-yunhai-1…
Sep 10, 2022 • 27 tweets • 13 min read
⚡️WATCHING:

#CAPSTONE appears to be garnering the DSN's attention over the last day or so. Continuous uplinks with no downlink like the anomaly observed after the spacecraft was released post TLI.

She was scheduled for TCM-3 in early September based on statements after TCM-2. I'm presently tracking #CAPSTONE on X-band and noting no emissions from it over the last few hours.
Aug 27, 2022 • 5 tweets • 3 min read
#ARTEMIS1 observational planning 🧵

Overall visibility of the spacecraft from my ground station location. Elevation above the horizon will be a key factor. As you can see during the early and late stages of the mission Artemis will be low in my sky.

Next lets consider the range to #ARTEMIS1 so a model of the expected signal level can be obtained using Free Space Path Loss (FSPL) assumptions. Data is only plotted when Artemis is above my horizon.
Mar 19, 2022 • 7 tweets • 3 min read
MERIDIAN 9 on it's Eurasian apogee.

As you can see here there's legit Russian military traffic here.

Aircraft spotters I make a call for you to pay attention to this 🧵. MERIDIAN 9, 990MHz transponder narrow data. This type of traffic has been observed for decades on the Molniya-T1 spacecraft too. It is thought to be part of the Russian Strategic Rocket Force's communication system.
Mar 18, 2022 • 4 tweets • 2 min read
MERIDIAN 8 RADAR re-emissions seen this morning.

Using the AM demodulator to examine the pulse dynamics of each RADAR. Here's another recording revealing a 4th radar with a much different higher pitched pulse pattern. It comes and goes so listen to the entire track.
Mar 17, 2022 • 4 tweets • 1 min read
My wife says this blown to bits Russian EW warfare equipment looks like our backyard. Not sure why they need 2.4GHz grid but we've seen other off the self comms equipment blown up too. If you look carefully at the second image there are two feeds, so they had two complete WiFi antennas. Most likely for some local link they planned to establish. I wonder if they use secure or open WiFi networks?
Mar 12, 2022 • 4 tweets • 2 min read
Russian military MERIDIAN 7 C-band this evening. There's now a 100KHz non-regenerative transponder on the band. I've seen these appear rarely on X-band but until now not on C-band. MERIDIAN 7 with the usual TTY beacon on 3610MHz.
Mar 6, 2022 • 8 tweets • 3 min read
Here's how to understand the RADAR data I'm sharing.

The Russian MERIDIAN satellites are in High Earth Orbit and have their apogees fixed above the Northern hemisphere over Russia and North America. This allows the spacecraft to see both places at once.

THREAD
1. Being in a highly elliptical orbit the MERIDIAN satellite is actually visible to observers on the opposite side of the world at a very low elevation in their sky. Here's an example plot of simulation of MERIDIAN 8 at the North American apogee visible from Ukraine.
2.
Mar 5, 2022 • 15 tweets • 6 min read
Some details on what is known about the MERIDIAN 990MHz transponder system. This transponder seems to be a legacy of the older Soviet MOLNIYA system as evidenced by this excerpt from a report to the US congress in the 1980s.
THREAD
When the last of the MOLNIYA's were still operational amateurs noted transponder activity from them while the spacecraft were on the Russian/European apogee. But by 2011 MOLNIYA went silent and was replaced by MERIDIAN and during the gap no one looked...
Mar 4, 2022 • 4 tweets • 2 min read
It's March 4th.

Today a piece of humanity's cast off technology will impact the Moon in a event that would have gone unnoticed had it not been for the work of a few folks looking up in unpaid and normally unnoticed toil... (1/4) In order to explore the Moon and for all of humanity to share in the potential positive aspects of that exploration and utilization we need to be able to monitor activity around the Moon in a more transparent and accessible way.

(2/4)
Feb 27, 2022 • 5 tweets • 3 min read
Based on research here's the layout of Russian military satellite communications at this time from Ukraine. 1st image is a sky view as you would see it from ground looking at the GEO satellites, 2nd a chart view of all assets visible and 3rd a map view. (1/n) ImageImageImage Understanding where command and control assets would need to view these satellites limits their tactical options to hide and helps one hunt them. (2/n)
Feb 27, 2022 • 4 tweets • 1 min read
A primer on the Russian military's MERIDIAN satellite constellation.

MERIDIAN is an High Earth Orbit (HEO) Russian military satellite designed to provide communications to northern latitudes (I.e. Russia et. al.). It is a modern version of the MOLNIYA constellation. Image The MERIDIAN constellation is primarily designed to offer communications to high northern latitudes where access to GEO satellites could be difficult or impossible.
Feb 26, 2022 • 4 tweets • 1 min read
This could be very well be a beacon of hope, the sound of resistance that can be heard around the world.

Russian military satellite MERIDIAN 8 reveals radar emissions that most are coming from Ukrainian forces defending themselves. After days of onslaught Ukraine stands.
Feb 26, 2022 • 6 tweets • 2 min read
This is the P-441 communication complex that the Russian military uses for MERIDIAN, RADUGA and maybe transponders on other assets. It uses C and X-band. On these bands a clear view of the satellite is needed. Many variants of this system exist. (1/n) Image Tactically, you'd likely want to hid this thing as it's a critical asset and part of your command and control which limits your options to deploy it. MERIDIAN could give you the ability to hid it and use those satellites high elevation to advantage. From the operating manual... Image