For those who haven't already seen, there is excellent work independently tracking and predicting the trajectory of Tianwen-1 by radio amateurs (using that word only technically, since they are very much pros).
The latest is predicting orbital insertion at 8 seconds before 1200 UTC on Wednesday 10 February, with a 386 km periapsis - burn starts a few minutes before that if you, like me, are planning your peanut consumption carefully this week.

Plenty of details to be found at these links (even a GMAT script and Jupyter notebook, and some doppler data, for the astrodynamically inclined).
https://destevez.net/tag/tianwen/
Daniel Estévez recent twitter thread with MOI images
Scott Tilley recent twitter thread

Daniel Estévez (Twitter)
@ea4gpz
"Acqusition of signal confirmed in @SternwarteBO shortly after 12:48 UTC. The spacecraft is still using the low gain antenna."

https://twitter.com/ea4gpz/status/1359484672456196097
https://spacenews.com/chinas-tianwen-1-ente...it-around-mars/

Tianwen-1 in orbit of Mars,... we should receive some photo,.. some time... i think...

...anxious to see some of the best then 50cm resolution images it will take in the near future...

Orbital insertion confirmed. CASC says landing attempt May-June timeframe now, per Andrew Jones of SpaceNews.

And another one! Mars is a spoiled planet! What a great couple of days it has been!

Congrats to the Chinese space agency, 6th to the red planet!

Interesting is the enormous numbers of firsts for the chinese in this mission,.. and the number of technologies they are using that are well tested on the chang's missions.

1 - Arriving Mars
2 - Orbiting Mars
3 - Mars close approach and High Resolution Image Mapping
4 - Mars Landing
5 - Mars Rover

The only achievment that will not be reached is Mars Return and Taikonauts to Mars.... and the first one they already proved at 1.6m/s2 moon gravity... big step to prove on mars 3.7m/s2 gravity... the second task,.. well, lets wait till they make it on Moon...

This will be the general thread for orbital operations. A new thread will be established for landing and surface activities once those occur.

"At ~13:14:20 UTC #Tianwen-1 switched from Low Gain Antenna (LGA) to High Gain Antenna (HGA) and already started to send some high speed data back to the CSNA Groundstations."
Anyone to decode that?...
@AMSATDL AMSAT-DL ON TIANWEN-1
https://twitter.com/amsatdl/status/1359643118782578690

21 May predicted date to land on Mars:
@PRCMarsRover
https://twitter.com/PRCMarsRover/status/1359834987277684740

Hopefully, they might be able to get a peek at neglected Deimos.

Amazing video taken by one of Tianwen-1 camera during orbital insertion.

Another one.

Congrats CASC,... continue sending every raw footage or data yu receive from Tianwen-1, never too much... I have worked with the Yutu-2 Data and must say that if we got the same from Tianwen-1 it will be stupendous...

I did some quick image processing on screenshots of Tianwen-1 video of Mars orbit insertion to enhance surface features.

Congrats to the Chinese for being number 6 to enter orbit!!!
Looks like it photographed Albor Tholus and Elysium Chasma.

Wonderfull views of Mars overlapped by tianwen-1, one idea, CASC should release another drop cam to get a far image of Tianwen-1 with Mars at the background...

Very cool !

I'm surprised at the amount of foreground movement in the solar array movie (circa 45s). Not quite sure what is going on - array flexing? And if it is a structural oscillation or some controlled movement (gimballing of something, it almost looks like something is stepping or limit-cycling)

I couldn't see anywhere by what factor those clips are sped up...

Planetary Society's Tianwen-1 page has it on Vimeo. Here is the info:

TIANWEN-1 ENTERS MARS ORBIT This video shows China's Tianwen-1 orbiter and rover entering Mars orbit on 10 February 2021. The spacecraft captured the images 3 seconds apart, and the entire video covers a period of 27 minutes. Video: CNSA/PEC via Andrew Jones

Hello everybody,

Tianwen-1 was now to perform a manoeuvre to move from its equatorial insertion orbit to a polar orbit with the objective of establishing a map of the Martian surface that will be used for the selection of the landing site.

https://twitter.com/guo_linli/status/1361114922277425153

TianWen-1 successfully carried out this maneuver :

https://twitter.com/guo_linli/status/1361277655069327364

This is really cool.

Im so excited to see where China decides to put the lander down

Tianwen-1's orbit has been adjusted further. The South China Morning Post reports that on Wednesday February 24, two weeks after initial orbit insertion, Tianwen-1 entered what they described as "its parking orbit", quoting the space agency CNSA.

"Each complete orbit will take Tianwen, or “Heavenly Questions”, two Martian days – or slightly longer than two days on Earth – with the lowest and highest points being 280km (174 miles) and 59,000km above the planet’s surface.

During its time in orbit, Tianwen-1 will use its cameras and spectrometer to carry out a detailed investigation of the Martian landscape and weather at its intended landing site before a planned touchdown in May.

“Currently the status of equipment is normal and all flight control systems are working as planned,” CNSA said.

It also acknowledged Perseverance's successful landing at Jezero Crater.

South China Morning Post Feb 24 report

Will we see orbital pictures from NASA of
the eventual landing or does the
ban on cooperation extend to even passive
activities such as imaging from orbit?

LRO has imaged each of the landed Chang'e missions, so presumably MRO can image the Tianwen-1 lander.

I don't know if it applied to LROC imaging, but there needed to be congressional approval for at least some LRO support. See https://www.scientificamerican.com/article/...ion-with-china/

From https://weibo.com/5386897742/K4AVS2zt8?ssl_...nd1614824040705

Is the low sun angle why the polar cap isn't bright white like we see in other images (both Hubble and other orbiters?) Or are others "enhanced" and this one is not?

Pretty typical for this season. See https://apod.nasa.gov/apod/ap980924.html for example.

The high resolution image with the small cones on the left edge is at 24.74 N, 110.17 E. I have not found the other location yet. This is right on a candidate site.

CTX image: CTX-J05_046929_2048_XN_24N250W

Click to view attachment

Phil

Hello,

I don't think the ban on cooperation extends also to innocent espionage activities.

Not sure what point you're trying to make. To image during the landing, the MRO team would have to know the time and place weeks or months in advance, adjust the spacecraft's orbit, and plan the images. If CNSA doesn't make that information public on that timescale, it's not happening. Post-landing imaging might be easier if there was some information about where to look.

To add a bit more detail, during a long winter night, a martian polar cap accumulates CO2 ice. Meanwhile, the other hemisphere is in summer, and warm and kicking up dust clouds. As atmospheric dust settles, it creates a thin layer of dust over the otherwise white polar ice of the winter cap. Southern summer is now over and we're seeing the northern cap for the first time in months. Next, the "spider" phenomenon will begin wherein sublimating CO2 ice will pop small holes in the dusty cover. Eventually, the CO2 will be gone and there'll be a dirty H2O ice cap at minimum size. And when that goes through martian autumn, new CO2 ice (and H2O frost) will make the cap grow big and white.

Of course.
I have never said that we could see such images but simply that a cooperation ban is completely foreign to that.

New Photos from medium-res camera. Detail of mars tiny limb.

https://mobile.twitter.com/AJ_FI/status/1375401463682306051

Click to view attachment

Map of Tianwen-1 landing site in Utopia Planitia based on coordinates published in an article by Andrew Jones.
Landing ellipse is 100x40 km, ellipse azimuth orientation estimated from orbiter's orbital inclination of 87.7 degrees.

Click to view attachment

A close-up of the central area.

Once the mapping thread for the mission is established the maps can be moved there.

Very nice maps! Once we are safely down I will start a map thread and these can be the first posts.
Phil

Wow, that's a gutsy first landing given how tough it is just to set down safely on a Martian surface with almost no obstacles and they are aiming for a spot adjacent to a rather scary looking crater. Wouldn't take much during that 7 minutes or so of "terror" timing to be off by a significant amount. I wonder how much hover and maneuver time they have built into the lander to be able to spot and avoid large obstacles at the last minute.

There are also a lot of pseudocones and lava wrinkles/channels in the landing ellipse too.

Given the size of the landing ellipse, there's very little chance of landing next to that crater right in the center of the ellipse. I suspect it's just coincidence that the ellipse center is on the rim of that crater.

John

Yeah - the landing ellipse is almost certainly larger than that entire image.

I guess there are many uncertainties, but this map is a start, based on limited data available.
Landing ellipse could certainly be bigger, I got 100x40 km from Twitter source, so far from 100% reliable. Couldn't find this information
in any Chinese source to confirm it's really true. The landing coordinates precision (24,748N, 110,318E) by itself carries about 100 meters imprecision in any direction.
CTX camera images are also not absolutely referenced, although I did check different images to confirm that the coordinates really work out to be at crater's rim.

On the other hand the two high resolution images published so far do show area at the center of the map, so they could be working towards landing near the center of the ellipse.

And thank you Phil. It is always nice to get encouraged by the best.

Apollo 12 in 1969 was trying to land close to the dead Surveyor 3 craft, which was located inside a sizeable lunar crater with internal slopes which could not be landed on safely. So the Commander asked the navigation team to target him directly at Surveyor, on the basis that, due to landing errors, this was the best way to AVOID hitting Surveyor or descending inside its crater! The same rationale might apply here -- aim for the place that you least want to arrive at, in the sure knowledge that actually getting there is extremely unlikely!

Apollo 12 in 1969 was trying to land close to the dead Surveyor 3 craft, which was located inside a sizeable crater with internal slopes which could not be landed on safely. So the commander asked the navigation team to targeted him directly at Surveyor, on the basis that, due to landing errors, this was the best way to AVOID hitting Surveyor or decending inside its crater! The same rationale might apply here -- aim for the place that you least want to arrive at, in the sure knowledge that actually getting there is extremely ulikely!

This phenomena played a role in the plot of the novel Gravity’s Rainbow by Thomas Pynchon, wherein the German V-2 engineers would observe the impacts of ballistic rocket tests from the center of the targeted bullseye.

We are entering the week distance window of the estimated landing date (17/may), from 10/may till 24/may.

As expected no info, but if they continue with the estimated dates, soon they will try the landing.

https://www.uol.com.br/splash/noticias/afp/...-afp-7-dias.htm
AFP international news for 7 days, land probably before May 15.

"China's Tianwen-1 mission getting set to try and land Zhurong rover on Mars"
https://www.abc.net.au/news/science/2021-05...nding/100101552

I don't think the entry module will be "detaching from an orbiter 70 kilometres above the surface", that's already in the atmosphere!
Instead it would be detaching from the orbiter somewhere along the orbit, the question is then how to change the entry module orbit to
intersect the atmosphere. For Viking, the entry module carried its own propulsion system for this purpose.

Indeed not less than 200km at periapsis. Timing for Zhurong to start its landing maneuver, in UTC, by Edgar Kaiser, based on the orbiter periapsis and time over the landing guessed coordinates on Utopia Planitia:

Mars in sight over China
2021.05.10 20:33:02 SKIPPED
2021.05.12 21:47:53 SKIPPED
Mars off sight over China
2021.05.14 23:02:44 DATE OF LANDING, BY SOURCE QUOTING CAST (by Cosmic_Penguin)
2021.05.17 00:17:35
2021.05.19 01:32:26
Mars in sight over China
2021.05.21 02:47:17 In sight with Jiamusi Antenna: https://en.wikipedia.org/wiki/Chinese_Deep_Space_Network
2021.05.23 04:02:08
2021.05.25 05:16:59
Last periapsis on May:
27/05/2021 06:31
29/05/2021 07:46

Date of Landing, by a source quoting CAST:
https://twitter.com/Cosmic_Penguin/status/1...701561030123521

More from Edgar Kaiser, that sugests we could have an atempt at today window: "Tianwen-1 showed quite some ground station activity along yesterday's approach to apoapsis. Tonight, at 21:47:53 UTC it will pass periapsis again."
Based on Mars position in the sky on the periapsis dates, chinese would have best comunication with the Tianwe-1 only today, bad sight on 14, 17 and 19th, so it apears that today could be the last window till may 21th.
https://twitter.com/df2mz/status/1392384013986410504

Orbital Period is 49h 14m 51s
https://twitter.com/df2mz/status/1391876766294331395

Good Thread following the landing from kaynouky
https://twitter.com/Kaynouky/status/1392051005664239619

Finally a date, not direct from CAST, but by a source quoting CAST's chief adviser of Interplanetary Exploration:

Landing on May 14, 23:11 UTC, 40 hours from now.

https://twitter.com/Cosmic_Penguin/status/1...701561030123521

The Zhurong will use the same navigation technology used on Chang'e-4, based on rotating stereo pair of câmeras. May have some changes, but the same methods used on one batch of data will deal with the other.

"Communication before (land) would be handled by Zapala ground station in Argentina." Edgar Kaiser
https://twitter.com/df2mz/status/1392764250481991681

After the landing the initial data will be passed to the Jiagmusi antenna, so problaby we will have some images on saturday.
https://twitter.com/df2mz/status/1392787065797062656

NFT on 1o photo by 15 from a Yangzhou company...
https://twitter.com/MarsZhurong/status/1392718169006030848

Curious. I don't recall telling ABC anything about altitude of separation, and certainly wouldn't have said that. Oh well!

I Believe the only real citation are beetween quotation marks... The problem with journalism, they insert a lot they get from all over the net beetween this quotes... My bad, i put quotes in all the text from the link. Removed it. Nice to see you here!