Good evening all, nothing new to report here. Just getting acquisition of signal on @LRO_NASA now. Shouldn't be too much longer before the moon completely clears the trees and we can begin listening seriously.
The 3m dish is trained on the moon now. China's Chang'e 5 test mission orbiter is load and clear!
I use @LRO_NASA and CE5T1 as alignment references to ensure the large dish is aimed properly as it's field of view is rather narrow.
First detection of the #Chandrayaan2 orbiter this evening. All looks normal there. #Queqiao is also visible down the band a bit. So lots of space traffic around the moon this night.
For those wondering, I have multiple radios recording data so as I show you interesting things away from #VikramLander's frequency I'm still recording there.
Here’s some of the hardware used. A pile of raspberry pi computers do some of the heavy lifting for tracking the antennas.
Here’s the 3m dish antenna. A retired TVRO antenna.
Here’s me making some parts of it.
Here's a clip of #Chandrayaan2 orbiter from a few moments ago. Good signals from her this evening.
Yes that's a pickup truck tire jack I used for declination control.
The 3m dish is mounted on a large cedar tree stump.
Just checked in on the #VikramLander uplink frequency and Goldstone is quiet (so far) this night.
Huge signal from #LRO_NASA as she descends behind the lime of the Moon.
As I head of to bed, here's a wonderful recording of #Chandrayaan2 orbiter sending a strong signal from the Moon. No signals so far from #VikramLander. Good night all.
And a preview to tomorrow's orbital analysis of #Chandrayaan2. The plane of the orbit is still fully visible from Earth and amplitude of signal frequency is lower than yesterday so this could last a couple of days...
This is the orbiter :-)
The Sun ☀️ bursts out from behind the clouds during a late summer 🌧 storm and creates some great visuals.
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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. ⬇️
I went back and looked at the erroneously timestamped data from the passes we thought detected OBJECT D and E finding that if I adjusted the timing YAOGAN-30 AA and YAOGAN-30 R passed closely to the track of these objects. ⬇️
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. 🧵⬇️
A telegram post by @roscosmos provides limited information of the status of #Luna25. Apparently, the spacecraft failed to adjust its orbit as planned.⬇️
Russian controllers now need to troubleshoot and fix the issue. This is complicated by their lack of a global deep space communications network. So recovery efforts will be limited to when the Moon is visible over Russia due to their geopolitical misadventures... ⬇️
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? 🧵⬇️
#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. ⬇️
The trajectory isn't arbitrary. You need to carefully line things up to the extreme to get anywhere close to the Moon. So it constrains where to look. As we're looking into the glare of the Sun, we need radio. ITU records report two bands, X and Ku-band. But wait...⬇️
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. ⬇️
Therefore, if you want to rush to get to the landing site it's too late. Therefore, you need to pick a new landing site under up coming terrain that may be suitable and also change the mission plan. Recalculate, adjust and then execute. ⬇️
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. 🧵⬇️
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... ⬇️
Data fit to released orbital parameters:
1 57320U 23213.95526600 .00000000 00000-0 00000-0 0 04
2 57320 21.4000 180.4625 9648325 12.6358 39.3505 0.10345282 04
# 20230801.30-20230802.61, 53466 measurements, 0.005 kHz rms⬇️
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. 🧵⬇️
Aerobraking is used to allow a spacecraft to lower its apopasis by using a planet's atmosphere to decelerate the spacecraft as it passes through the tenuous upper atmosphere of the planet at periapsis at just the right altitude as not to cook the spacecraft and max. drag. ⬇️