They have been very open to Chang'e raw data. The Chinese understand that the biggest enemy of Space Exploration is politics, so they are leting their space program run very freely. I think thats why they are geting so much success.

I expect then to be open with the Tianwen-1 data, like they did with the chang missions.

Apparently they made some precautions, they applied a special microstructure coating on the solar panels to reduce friction between dust particles and surface, and the two side panels can be tilted by electric motors to remove accumulated dust by gravity and improve sun illumination.

Thank you for that link Bobik. That was very informative.

I recently came across this poster. I don't know if it is genuine or not but what surprised me is that microphone under the mast cameras. I don't recall seeing a microphone in any Zhurong instruments list... anyway, here is that poster slightly modified in Topaz Gigapixel.
Click to view attachment

From here:

Agreed, bobik, thank you for this article which has a bunch of details I hadn't seen (though I'm realizing I have a lot to catch up on, so it's probably not new to everyone). In particular it points to a bunch of innovations motivated by lessons from prior US rovers and the Chang'e missions, among them:

(1) answers the question from upthread about the two circular features in the center of the rover top surface:

QUOTE

In addition to the solar panels, there are two circular films on the body of the rover, which look like a greenhouse. It is indeed a "greenhouse" for the rover, but there are no plant seeds in it, but phase change insulation materials....
...
If the control scheme on the moon is copied, even if the wake-sleep process will not affect the rover, the cumbersome start-up, self-check, and adjustment procedures will also Take up a lot of time. Therefore, the rover is also working at night.
...
During the day, "Zhu Rong" thermal insulation material liquefies to absorb heat, and at night it solidifies and releases heat. This special feature allows Zhu Rong to maintain a constant body temperature even under drastic changes in the external environment temperature, so that the various components it carries can work more stably and for a longer period of time.

(2) also mentions the ability to turn the wheels sideways 90 degrees and (!) unlock the suspension joints, using the wheel motors to raise or lower itself and "creep" out of any situation where it gets stuck. - Edit: here is a paper by the cited author on the subject: https://www.sciencedirect.com/science/artic...094114X1830171X - paywall but with graphical abstract

Don't know if other orbiters would help. I believe the orbit must pass near Zhurong to help. Thats why they are changing and lowering the tianwen-1 orbit.

I have a big doubt.. If the navigation is based on Photogrammetry, using a heavy pack of images at each processing. How will they help that from earth with this kind of dificult to receive the data....

Following Space Exploration is a guide to a heart atack...

"China's Zhurong rover Mars EDL:
1) 9 minutes of something approximating terror
2) 18 minutes of light delay/ontological deliberation
3) 90 minutes of info blackout & confusion
4) Official success
5) 2 Days & counting of so where are the photos?"
Andrew Jones

https://twitter.com/AJ_FI/status/1394052879510605825

No chance other non-NASA spacecraft can act as relays? MOM, Hope, etc? If not, this is going to be a slow ground mission (Galileo but one planet inward!)

A Image that tells a lot, we only see a good chang'e-3, chang'e-4 nominal, chang'e-5 nominal, Tianwen-1 nominal till now... But a image of Tianwen-1 chief designer Zhang Rongqiao in tears after the succesfull landing tell a lot about what we can't see....

http://www.xinhuanet.com/english/2021-05/16/c_139949426.htm

Neither MOM nor Hope have relay hardware.

Exomars TGO does - but it's not clear to me that it's compatible with Zhurong given that it's an Electra radio supplied by NASA-JPL.

In early operations - Spirit and Opportunity survived with just MGS and Mars Odyssey. One could quite easily design a concept of operations that works with a single relay asset in a longer period elliptical orbit. Infact- depending on link budget and pass duration, you could get a huge amount of data back with a spacecraft in a more elliptical orbit. MAVEN and TGO return the lions share of data from MSL, for example.

Even if the orbiter were to fail for some reason - the size of the high gain antenna on this rover would suggest something around 1 - 20 kbps of direct to earth downlink if required - you could return a few tens of megabits per sol that way if necessary.

Galileo operated with around 0.1kbps of downlink. This is not going to be 'Galileo but one planet inward'.

IIRC Beagle 2 had a similar 'solar accumulator' feature. I suspect there's only a range of (small) vehicle sizes where they make sense. On the one hand it lets you store all the solar radiation as heat, so per unit area you are getting more joules into the system to tide you over the cold night. On the other hand, if you covered the same area with insulation and with solar cells, you'd only intercept 25% or so of the energy, but you'd be able to control it better as it's electricity in wires which you can switch easily. Above a certain size, that controllability is probably more important (rover overheating is often more of an issue than freezing..)

Mars Express will help on the relaying: https://twitter.com/esaoperations/status/12...4814672899?s=21

In fact there are murmurs that MEX will make its first communication session with Zhurong later today: https://forum.nasaspaceflight.com/index.php...8231#msg2238231

The orbiter probably has also made its orbit lowering burn to the main “communications orbit” a few hours ago, updates pending.

Of course, Spirit and Opportunity did have Direct-To-Earth (DTE) via their high-gain and low-gain antennas. The DTE would presumably have been critical in working the Spirit anomaly.

And remember that the two 1st images taken by Viking Lander 1 just after landing (Sol 0) and received 'live' on Earth weighted only 730 Ko alltogether (*) for transmission through a single orbiter (VO-1) which was also on a very elliptic orbit (32,800 by 1513 km).
The Chinese need a greater transmission capacity to return the hi-res color images they want : so, it will take more time for them to retrieve this much greater amount of data.

Click to view attachment
Click to view attachment

(*) This looks very primitive compared with today's technologies, but this imaging strategy worked very well (and the media were stunned by the results)

Together the next mars mission i would believe china will send a network infrastructure in another ship to orbit, land or both. First big problem is obvious the datalink beetween the two planets....

I found the coordinates Phil mentions on this news site https://m.chinanews.com/wap/detail/zw/gn/20...5/9477804.shtml


Contrast with this GE Mars snapshot of the site area to which I added the Tianwen-1/Zhurong location and uncertainty [+/- 0.05deg] bounding box.

Click to view attachment


Fernando
PS: I intend to, in a future post, perhaps in the maps thread (hint, hint), cover the two CTX images I have added to GE's Global CTX overlay.
PPS: There aren't any HiRISE images of the area but a HiWish has been registered.

I was talking about relay. I specifically mentioned the likely DTE performance later in the same post.

"#Tianwen1 now in new "relay" orbit with a Period of 8.2 h (2.927128 rev/d),"
"Peri height 260.990860 km. Next Apoapsis 12:50 UTC, next Periapsis at 16:56 UTC."
AMSAT-DL
https://twitter.com/amsatdl/status/1394271922402308100

Orbiter passing now 3 times a day at a distance of 261 km from the rover.

"Patience is required, suggested Zhang Yuhua, deputy chief commander of the Tianwen-1 Mars mission"
https://www.leonarddavid.com/china-mars-mis...topia-planitia/

Edgar Kaiser could see a full half orbit of Tianwen-1 without a break in sighting.

Can they even take any images until they stand up the rover?

It has been reported that the lander has cameras, so I assume so. How long the lander's cameras last after rover deployment is TBA, but I imagine it will be a very brief period.

As we seem to be on standby waiting for the images, do we know anything about rock abundance on the landing site?
The VL2 site, also on Utopia though quite some distance away to the NE, looked awfully rocky to my non-expert eye.
Is VL2 a good analogue for the sort of terrain we should be expecting to see?

We can try so mosaic the images from the orbiter and try to predict wich craters ly near Zhurong...

Click to view attachment

Using the updated landing location (25.1N, 109.9E), here's an estimate on the landing location using a pair of CTX images (D22_035786_2060_XN_26N250W and F04_037553_2068_XN_26N250W). Location could be a bit off due to the location available not being precise enough and due to this only using the raw spice location for one of the images. Still no HiRISE images of the site.

Do you have the stereo pair of it?

What are the white streaks which are everywhere in Utopia imagery? Sand, or frost?

From here showing Tianwen-1's new orbit.

They look small sand dunes to me.

VL2 was near the crater Mie though I'm unsure if that directly contributed to the rocks we see. There is more discussion here:

http://www.planetary.brown.edu/pdfs/3555.pdf

We know the area is much less rocky than VL2 - HiRISE makes that very clear (though HiRISE coverage doesn't yet reach the exact landing site). And for a rover that's good. No small rover could cope with the VL2 site. Mie's ejecta does reach the VL2 site (a large ejecta lobe is to the south) and probably contributes many of the rocks.
Phil

Agree with you Phil. It's not because the Chinese land in 'Utopia' that the landscape will look the same like the one revealed by VL2
Utopia is a very vast plain with various geological units, and at the latitude of VL2 (48°N), it is mostly made of a permafrost (ice-rich soil) below a ~ 25 - 30 cm layer of dry sediments.

=>> My guess is that the Zhurong landing site at 25°N will be very flat with small rocks and pebbles (thus, much, much less rocky than VL2), and will look like the InSight landing site, but with some spaced-apart dunes and low-lying crater rims.
For sure, this site is the safest possible for testing landing technologies and a first try.

Topic title changed to reflect successful landing and in anticipation of surface operations.

I might also add that the Viking landing site team did not expect those rocks. They thought they were landing on a layer of sand which would cover any rocks, and they would not have gone to that site if they knew how rocky it was. The orbital images were far less satisfactory than for the Viking 1 site. We are so much better prepared for site selection today - superb images and thermal inertia data to reveal patches of rocks smaller than HiRISE can see. If The Chinese site selection people thought their site was anything like VL2 they would not try to land there.
Looking forward to the first pictures!

Phil

What's the theory behind those grooves (cracks?) and round shaped buttes in the general area? I've looked around the MRO HiRISE and CTX image catalogs and they seems to be interesting features to look into should the rover made that far.

I don't think the rover will go far, unless they stablish a better comunication with earth. I Believe the decision on which path to take will be done similar to the used for chang'e-4. It depends on images send to earth.

The first communication from Zhurong was only 2 bytes per second, direct to earth. Now It will use UHF communication and X-band passing through the relay, going to a 2.5 and 6.25 MB of data per day. Thats my understanding from this link on Weibo. So it would be impossible to get an image at the first days. But if they success on using the relay options we will got something soon.

If the information proceeds they have already downloaded less then 200 kB in 3 mars days... Thats why no image...

So,.. Zhurong has not yet used Tianwen-1.... I used google translator, so if anyone can get a better info from the pics or the text.

"最近很多人问为什么祝融号到现在依然没有图片回传?着陆两三天了都还没回传是不是有问题balabala，诶，这可别着急，下面就分析一下为什么直到现在都没有照片的原因，如图所示(资料来源@航天爱好者网 )，落火当天使用的是自主的直接对地通讯方式，这个对地通讯模式的传输速率仅仅为16bps，也就是一秒传输2个字节，在这种带宽下，仅仅只能判断探测器状态，极其难以实现图片回传，如果一张100KB的低清图片没有经过压缩的话，使用这个小水管回传需要大概14小时左右，这还是不考虑祝融号本身测控的所占用的带宽，但是，在三个火星日之后，也就是今天晚上呢，火星车会和在轨道上面的天问一号第一次尝试建立UHF通讯链路，每次持续8-10分钟，建立以后每天能够回传20Mbit(2.5MB）的数据，再之后每3天会建立一次X波段的通讯链路，这种通讯链路的每次通讯的数据就达到了50Mbit(6.25MB）的数据，所以，如果一切都顺利的话，今天晚上可能拿到祝融号的第一批大小约为2.5MB的数据，就让我们敬请期待这2.5MB小小的数据包里面有没有着陆后的照片吧。如果没有也不要灰心，再等几天，数据会陆续的传回来，相信早晚会看到我国第一张从火星表面发来的照片的!
@北斗_玉衡 @大英良心汉弗莱 @脱欧入亚卡菊轮"

https://m.weibo.cn/detail/4637909523366148#comment

Good compilation of Events from 2015 till now and upcoming (possible):
https://www.shymkent.info/space/chinese-spa...ission-to-mars/

"Upcoming events
18th May 2021: First images of Mars rover Zhurong will be received as early as 18th May 2021 at 1am UTC (Sol 3). At this time the first data packages will received. But it is not clear if the first data packages have images of the martian surface inside or only telemetry or science data.

22nd May 2021: China’s Mars rover Zhurong will roll down from the descent module to the martian ground (Sol 7).

27th May 2021: China likes selfies. Like the photo sessions of Yutu-1&2 with the Chang’e-3&4 landers on the Moon also Zhurong will do a photo session between rover and the descent module (Sol 13).

28th May 2021: Science program will start on the surface on 28th of May(Sol 14). Zhurong will perform 90 days of science on the Mars. After 90 days they will slow down or stop the mission of the Mars rover. The Tianwen-1 orbiter will change it’s orbit again. The orbiter will enter a science & mapping orbit to inspect and to map the planet Mars."

What science is ahead for the Zhurong Rover in Utopia Planitia?

Nature Astronomy (no firewall)

Reading between the translation...

So far only 16bps on X Band DTE

They're expecting to return 20 Megabits through UHF daily starting on Sol 3 with a single 8-10 minute UHF Pass.

The 50 megabits per sol through DTE X-Band seems a little big.....if they can handle 10kbps DTE it's probably doable. Doing it every 3 days seems reasonable as well.

Be nice if NASA or ESA offered some bandwith. Its just data, im sure they could make it happen

There's a major piece of legislation forbidding cooperation between the US and China. Our forum's no politics rule means I can't get into details, but even if it didn't exist, there's the whole matter of trust that what is received on the ground is really accurate regarding what is happening at Mars, and without that trust, it's not viable. It is not an issue for ESA and NASA, but China is another matter. We can only hope that future missions do not suffer from Earth-based politics....

NASA is legally prohibited from collaborating with China in any way.

ESA has already given ground station time for downlink and ranging/tracking to this mission and Mars Express will be conducting relay.

Tianwen-1 has stablished a orbit with a duration of exactly 1/3 martian day.
by Edgar Kaiser
https://mobile.twitter.com/df2mz/status/1394749129310580738

We got a relay!

"China's lunar exploration program posted on its official account on social media platform WeChat on Tuesday.
The orbiter has completed its fourth braking near Mars, entering the orbit for relay communication. Zhurong has established data link with Tianwen-1's orbiter and successfully transmitted data to Earth through it for the first time on Monday"

https://news.cgtn.com/news/2021-05-18/China...r84M/index.html

djellison: "NASA is legally prohibited from collaborating with China in any way."
I understand that the wording is to the effect that NASA has to have the approval of Congress (presumably via an oversight committee) before it can cooperate. Not that I am an expert. Cooperation on specific points might be permitted if approval could be obtained. Of course, that approval might be difficult to get.
Phil

Just saw some murmurs that the 1st Mars surface photos from the Tianwen-1 lander/rover will be released in a few hours (possibly at the 7 pm news on state media CCTV, which would be after 11:00 UTC).

Yes Phil ! This is true for cooperation on specific matters, like information storage and share at NSSDC which has been discussed already for their Moon missions but not yet implemented

They are so focused on Zhurong and Tianwen-1 that the Yutu-2 are not moving, its all stopped on the last lunar day to put all efforts on Zhurong. After Zhurong starts making its science procedures Yutu-2 will resume activities...
By Andrew Jones
https://twitter.com/AJ_FI/status/1394930830439591936

First Photos!

Finally! Are the two gifs showing the release of heatshield, backshell or both?

It's the complete lander separating from the orbiter.

OK thanks.
A rectified and sharpened version of the picture taken by the "Hazcam" of Zhurong rover.