Discover and read the best of Twitter Threads about #Change5

Most recents (10)

The last observation before #Change5 'disappeared' after Dec 2nd, was 19 degrees from the Moon on the western side. Perhaps just before a burn!? This as you will see is significant to understand CE5's present trajectory and why I'm pretty much convinced it is in a DRO now. (1/n)
The geometry of Dec 2nd timing is curious to say the least. If you examine this plot you'll not there are a number of possible DROs. If you measure the elongation angles for the second closest to the Moon you get ~19 degrees. (2/n)
I'm not sure if it's required or just easier, but #NASA is using the elongation point to do their insertions to a DRO. It's referred to as a Distant Retrograde Insertion (DRI) of course!
Read 8 tweets
What in tarnation is a Distant Retrograde Orbit (DRO)?

For those wondering what I'm waving my hands about these days about here's a THREAD about what a DRO is and why it may be something you hear a lot more of soon... (1/n) Image
A DRO is a long term STABLE orbit for a very small mass object around the smaller of two much larger bodies that are in a two-body orbital system. As the Earth has a Moon, one could place a spacecraft in a DRO of the Moon. (2/n) web.archive.org/web/2015011122… Image
The general parameters of a DRO are about +/- 70000km form the Moon along the axis to the Earth and between 70000-110000km on the perpendicular axis. The period is around 13-14 days. This is why it's call 'distant'.
Read 8 tweets
#Change5 DRO state vector estimate with rationale.

Amateurs lost signal ~2021-12-03. About 3 integer periods of ~13 days, which is around the optimal DRO period. We appear to be seeing spacecraft at eastern elongation now. So... (1/n)
From what I understand of DRO insertion geometry one likes to enter DRO from one of the elongation points not the EM-L1 or EM-L2 points. This insertion burn occurred ~ 2021-12-03. SOURCE: ntrs.nasa.gov/api/citations/…
Location of #Change5 this evening is within error bars of rough location of a hacked together state vector estimate is. (2/n)
Read 4 tweets
Could #Change5 be in a Distant Retrograde Orbit (DRO) of the Moon pulling off a space first?

CE5 is ~15deg east of the Moon suggesting it is ~100000km distant from the Moon. I made a model DRO in GMAT seeded it with a start from EM-L2 around 2021-12-01 00:00 UTC, Hmmm... (1/n)
Examining papers on the upcoming #NASA SLS EM-1 mission that will use a DRO reveals the geometry somewhat fits the limited observations we have of #Change5 since it was recovered a couple of days ago. (2/n) SOURCE: ntrs.nasa.gov/api/citations/…
Range estimates based on SNR of #Change5 X-band signal appear to be consistent with it being approximately at a lunar distance. If it is in a DRO this would be a first scoping the upcoming #NASA SLS EM-1 mission. (3/n)
Read 4 tweets
Steffan Watkins provided a wealth of AIS data from MarineTraffic about the journey of Yuan Wang 3 to the #Change5 re-entry skip point in the Arabian Sea. The data reveals that the ship did some interesting stop and goes prior to arriving on station to look at what? THREAD.
2020-12-10 UTC between 18:30 & 22:30, Mars was at the zenith when they stopped and set just before they got underway again. Perhaps providing support for TIANWEN-1 on the way to Mars?
2020-12-11 UTC between 14:20 & 22:05 more TIANWEN-1 watching at the zenith again it appears. The Mars bound probe has a big signal on X-band which is also used by #Change5.
Read 8 tweets
Here's a plot of an estimated ground track for the #Change5 re-entry.
This THREAD will discuss:
- Evidence supporting this ground track,
- Alternatives that have been excluded,
- 'Skip' re-entry profile visibility characteristics,
- State vector confirmation of timings/position.
Two possible re-entry ground tracks have been explored. The one presented is favoured because the tracking ship Yuan Wang 3 is now presently at the 'skip re-entry perigee'. Using AIS data dug up by @steffanwatkins the ship has been loitering in the area for a day or so now.
@Cosmic_Penguin noted the following graphics posted during pre-launch coverage of training efforts which showed the location of Yuan Wang 3 and the major re-entry event locations. Despite some oddness in the presented data the plan looks solid.
Read 14 tweets
I consulted with Astrogator Mike and we are getting closer to a ground track estimate for #Change5 during re-entry. The s/c will skip off the atmosphere over Yemen. The timing of this is directly related to TCM corrections and the accuracy of our model so should improve. THREAD
#Change5 like the Apollo capsules will use the atmosphere to steer itself. Thus creating a lot of complexity and uncertainty in modelling the actual ground track to aid observers. We are looking at a few ways to spit ball a ground track for those living in the general area.
As it will be night time over this part of the world it should be a spectacular show for those lucky enough to see it.
Read 4 tweets
01/12 > Déchiffrer le code énergétique des cellules pour améliorer les thérapies anticancéreuses bit.ly/3g0vsdW via @CNRS #LaMethSci
[L’étude à découvrir] 01/12 > SCENITH : Une méthode basée sur la cytométrie en flux pour profiler fonctionnellement le métabolisme énergétique avec une résolution monocellulaire bit.ly/39z0vfV via @CellPressNews #LaMethSci
02/12 > Le #RoyaumeUni approuve le #vaccin contre le coronavirus #Pfizer / #BioNTech pour le déploiement la semaine prochaine bit.ly/3lvJs0G via @newscientist #LaMethSci
Read 5 tweets
23/11 > Lancement réussi pour la mission chinoise qui vise à décrocher un morceau de #Lune bit.ly/33chyjU via @lemondefr #Change5 #LaMethSci
24/11 > Malgré les confinements lié au #CoVid19, les gaz à effet de serre sont toujours à des niveaux records prévient l’#ONU bit.ly/2USDkEK via @ScienceAlert #LaMethSci
23/11 > Découverte d’une “galaxie fossile” enfouie dans la #VoieLactée bit.ly/33cSPfe via @Trust_My_Science #LaMethSci
Read 6 tweets
[Lancement] - 🇨🇳 Longue Marche 5 (CASC), Chang'e 5

Allez il est temps de débuter ce thread du lancement de Chang'e 5 vers la Lune! Le décollage est prévu vers 22h heure de Paris, mais le direct depuis Wenchang a déjà débuté...

Allez la Chine, Allez Chang'e !

#Change5
Le direct est pour l'instant disponible sur Weibo, à cette adresse:

#Change5

live.media.weibo.com/show?id=104215…
Pour l'instant, la nuit tombe doucement sur la base de lancement de Wenchang. Le portique de lancement est encore fermé, le lanceur se cache encore dedans...
Read 64 tweets

Related hashtags

Did Thread Reader help you today?

Support us! We are indie developers!


This site is made by just two indie developers on a laptop doing marketing, support and development! Read more about the story.

Become a Premium Member ($3.00/month or $30.00/year) and get exclusive features!

Become Premium

Too expensive? Make a small donation by buying us coffee ($5) or help with server cost ($10)

Donate via Paypal Become our Patreon

Thank you for your support!