Zhurong Lander/Rover, Surface Operations at Utopia Planitia Options

[nprev]

Per this source, landing currently scheduled for 14 May/2300 UTC. Please post any relevant information and updates here.

GO ZHURONG!!!!!

[Huguet]

CNSA: "China’s first Mars exploration mission, Tianwen-1 probe has functioned normally since its successful launch on July 23rd, 2020. On February 10th, 2021, Tianwen-1 probe entered the Martian orbit for scientific exploration and huge amount of scientific data are available up to date. With the evaluation of the flight status, Tianwen-1 probe is scheduled to perform landing campaign targeting Utopia Planitia at the proper slot from the early morning of May 15th to May 19th Beijing time."
http://www.cnsa.gov.cn/english/n6465652/n6...00/content.html

Oficial statement from CNSA, so the window starts today 23:00 UTC, but they can skip it and have two more windows beetween 15 and 19, beijing time is UTC + 8, so we have this 3 dates of periapsis for landing, by Edgar Kaiser:
2021.05.14 23:02:44 Start of the Windows of Landing, oficial statement by CNSA
2021.05.17 00:17:35
2021.05.19 01:32:26
https://twitter.com/df2mz/status/1391876766294331395

Interesting point remembering the importance of amateur radio enthusiasts on space exploration. Without then we would be blind.
https://twitter.com/AJ_FI/status/1393164426593902597
Nice Interview with Scott Tilley from British Columbia about listening Tianwen-1 over Mars:
Tianwen-1, on the other hand, has a relatively large antenna with a booming signal. “China probably plans to use it as a relay for future Chinese space missions,” Tilley speculates. “This makes it a good target for hams hoping to bag their first Martian spacecraft.”
https://spaceweatherarchive.com/2021/02/16/...nals-from-mars/

[Huguet]

Live of the landing or skip with radio signals by RocketGyan starting at 22:15 UTC:
https://www.youtube.com/watch?v=TGijtGSUEJs

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[Huguet]

Live signal from Edgar Kaiser, will go live till 23:00, minutes before landing possible attempt, we should get something in 30 minutes indicating if they will try it today.

Now we have two feeders getting tianwen-1, one live, the other will start 22:15 UTC.

The separation would happen more or less at 18:00 UTC if they will try it today, it will be visible at Edgar Kaiser live.

https://www.youtube.com/watch?v=RupTNWUuxsg

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[Huguet]

They are doing a maneuver now! Separation... or alignment of orbiter to do the separation... or changing from High Gain to Low Gain Antenna

https://www.youtube.com/watch?v=RupTNWUuxsg

Lost it on Edgar Kaiser, so HGA not available, action done, possible atempt landing today.

Signal lost by an action on orbiter at: 16:09 UTC.

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[Huguet]

Possible cofirmation of landing process happening from Zhurong official weibo account.

"Tianwen1 has entered the landing process! I am expected to start entering the atmosphere of Mars tomorrow (UTC in a few hours) and land at an opportune time"

Landing process started at 16:01 (16:08 minus 7 minutes delay of the signal...)

https://twitter.com/df2mz/status/1393240504020647941

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[Huguet]

Passed separation time, if all goes well we should got a signal 1 hour from now.
AMSAT got a signal from LGA. Everything seens ok.

[djellison]

The Amsat DL team with their large antenna in Bochum are tracking it live - https://www.youtube.com/watch?v=hEfAxmkBagg

[Phil Stooke]

If we have a successful landing there will be a map thread. It may be very sporadically updated depending on how operations are covered.

Phil

[Huguet]

The Amsat DL team with their large antenna in Bochum are tracking it live - https://www.youtube.com/watch?v=hEfAxmkBagg

Very nice link, High Gain Antenna back alive!!!!! Everything seens perfect...
Possible Separation ok and orbiter returned to his normal position.

Oh my,... 2 live feeds... 1 more to join,.. this is just so perfect.

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[Phil Stooke]

The landing site is probably the same one indicated at the left here. I have not seen anything specific about the location.

The small crater names were given back in the early 1970s when this area (centered a bit to the west) was considered for Viking under the name Amenthes.

Phil

[Huguet]

We got a new burn, probably to distance the orbiter from the lander or unlocked something,.. or else...

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[kenny]

Regarding the landing burns, the procedure is apparently to de-orbit the whole assembly (both orbiter and lander) into a descent trajectory which intersects the Martian atmosphere, then release the orbiter. After separation, the orbiter portion does another engine burn to raise itself back into Mars orbit to continue its mission. The lander in its entry shell continues down into the atmosphere. This avoids having to provide separate de-orbit engines for the lander capsule, as was the case with the US Viking probes.

[Huguet]

Regarding the landing burns, the procedure is apparently to de-orbit the whole assembly (both orbiter and lander) into a descent trajectory which intersects the Martian atmosphere, then release the orbiter. After separation, the orbiter portion does another engine burn to raise itself back into Mars orbit to continue its mission. The lander in its entry shell continues down into the atmosphere. This avoids having to provide separate de-orbit engines for the lander capsule, as was the case with the US Viking probes.

Thanks,.. that can explain the last burn, i think the next lose off HGA will be the orbiter changing its direction to image the landing. we should have that 3 hours from now... so the separation was more a drop maneuver then a normal separation... I expect then to release a nice footage of the heat shield, parachute, burn landing. That would be perfect.

[Huguet]

The orbiter just turned from HGA to LGA, possible its starting to image or to follow somehow the lander. Very early to do that, possible it is now making the burn to achieve parking orbit again. Less then 3 hours to heat shield burning.

Its impressive that we are geting a good info from a dish with 1 meter in diameter...

[Huguet]

HGA back alive, orbiter possible returned to parking orbit. Everything good to wait for the heat shield burn, that will start in 1 hour.

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[kenny]

The South China Morning Post (Hong Kong) reports : "Ye Peijian, a member of the Chinese Academy of Sciences and a key researcher on China’s lunar programme, said during a Thursday lecture at the Beijing Institute of Technology that the rover would land at about 7.11am Saturday Beijing time, local media reported."

So now that the separation of the lander has apparently occurred, there can be no delay to this plan, as was previously an option. It cannot now return to Mars orbit.
So landing expected at 23.11:30 UTC Friday 14th.

Then I presume we need to add on the current light time for radio signals to arrive from Mars, which is 17 minutes 43 seconds.

So I guess landing confirmation signals can arrive no earlier than 23:29 UTC.

[Huguet]

A resume from the feed by Edgar Kaiser with his 1 meter dish, clearly showing the deorbit burn, avoid colision burn (small one) and burn to get orbit again (last big one).

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[Tom Tamlyn]

Fabulous video of the burn just played on the live feed.

[nprev]

You watching the RocketGyan feed, Tom, or do you have another?

[kenny]

what web site was that, Tom?
If you mean Rocket Gyan's live feed, he was only showing an old video of the initial Tianwen Mars orbit insertion burn.

[Tom Tamlyn]

Nick, it was the RocketGyan feed at the link posted by Huguet here:http://www.unmannedspaceflight.com/index.php?s=&showtopic=8627&view=findpost&p=252215

I hadn't been watching much at all, but a few minutes ago tuned in just in time to catch the video. You could see the spacecraft wobble under the influence of the rocket thrust.

Kenny: Ah, thanks, hadn't been listening closely so didn't realize it was the orbit insertion burn. Sorry about gushing over such OLD NEWS.

This post has been edited by Tom Tamlyn: May 14 2021, 11:13 PM

[Explorer1]

Perhaps there will be comparable imagery of the lander separation.
Should have landed by now; waiting for the signal to get to Earth....

[kenny]

Rocket Gyan livestream is quoting Chinese commentators stating successful landing, without details yet.

[kenny]

Several rumours of a successful landing on Weibo, including one from an apparent insider to the mission.

[Huguet]

I just couldn't get any feeder after Mars go off sight from Edgar Kaiser and AMSAT in Germany.... so i didn't see the maneuvers to image the landing... I think its time to find or put a dish on Americas to this amateur purpose of video streaming huge events like this one.... and it will became more and more common.

[Huguet]

Official source saying landing nominal.
https://twitter.com/AJ_FI/status/1393358422700183552

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[nprev]

CNSA just tweeted #Mars!!!

[Hungry4info]

CGTN:
#BREAKING China's Tianwen-1 probe lands on #Mars
https://twitter.com/CGTNOfficial/status/1393365096609435648

And also from Xinhua.
https://m.weibo.cn/detail/4637036026006686

[nprev]

Congratulations to CNSA on this achievement!

[Explorer1]

Apparently: 109.7 E, 25.1 N; (top middle of this map: https://en.wikipedia.org/wiki/Amenthes_quad...Region-mola.png )

A bit North of the crater called Bluff....

[Hungry4info]

From here.

On CCTV it was reported that "first opportunity to downlink photos will be around midday-afternoon BJT", i.e. within next few hours. The relay orbiter is currently on the opposite side of Mars.

[volcanopele]

CTX image of the landing site. scale is 5.7 m/pixel. The large crater at bottom is 1.8 km across.

[Guest_Steve5304_*]

WoW!!

Congrats to the Peoples Republic of China


What an amazing achievement for such a new space program!

I hope we start getting Chinese posters!

[Phil Stooke]

The coordinates have been moved a bit, to 25.1 N, 109.9 E. That moves it out of the CTX image volcanopele posted and puts it about here:




The hills seen in the first orbital image are at lower right.
Phil

[kenny]

Chinese news media are reporting "nine minutes of terror" during the landing, so two more than the usual American seven minutes!

The official landing time from CGTN was 23:18 UTC (GMT) so 7 minutes later than was being predicted by Chinese sources before the descent.

The whole craft (both orbiter and lander) started descending from orbit at about 17:00 UTC and entered the long descent trajectory. The landing module, consisting of the lander and the rover, separated from the orbiter after 3 hours at about 20:00 UTC according to the CNSA. Then, 30 minutes later, so about 20:30 UTC, the orbiter fired its engine to leave the decent trajectory (which it was also now on, temporarily, to drop off the lander) and returned to a safe orbit. After being dropped off the lander had a 3-hour voyage to entry interface. These announced times seem to be approximate.

I believe this is a new technique for Martian atmospheric entry, but was previously used by Galileo at Jupiter and Cassini at Titan.

[kenny]

Xinhua News Agency has reported more details of the landing. No pictures as yet.

It took ground controllers more than an hour to establish the success of the pre-programmed landing. They had to wait for the rover to autonomously unfold its solar panels and antenna to send the signals after landing, and there was a time delay of more than 17 minutes due to the 320-million-km distance between Earth and Mars.

"The Mars landing of the Tianwen-1 mission has been a total success," Zhang Kejian, head of the CNSA, announced at the Beijing Aerospace Control Center.

It will take a further 7 to 8 days for the rover to detect the surrounding environment and conduct self checks before moving down from the lander to the Martian surface.

Xinhua post-landing update

[ollopa]

Xinhua News Agency has reported more details of the landing. No pictures as yet.

It took ground controllers more than an hour to establish the success of the pre-programmed landing.

Xinhua post-landing update

Is there someone with some insight into the likely comms opportunities? For instance, I have seen speculation that on May 17 Zhurong will communicate with Tianwen-1 via ESA MarsExpress. I would have assumed that Tianwen-1 is over the horizon *much* longer than lower-orbit assets. Am I missing something? Is someone running the numbers?

[Huguet]

https://mobile.twitter.com/df2mz/status/1393617519257268225

"This screen shot from CCTV seems to show that the Zhurong rover already communicated with Earth, opened its solar panels and downloaded some data." Edgar Kaiser

"rover landed still; started to communicate with earth; communication finished; rover unlocked/lifted up; solar wings opened; obiter adjusted position . Data downloaded in last 3 lines"

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[rlorenz]

I believe this is a new technique for Martian atmospheric entry, but was previously used by Galileo at Jupiter and Cassini at Titan.

New for Mars orbiters, perhaps. But Beagle 2 was delivered this way on Mars Express' hyperbolic approach

[Hungry4info]

Some rough translations of the screenshot here... I think. Feel free to improve upon them with the times and copyable text.
8:01:24 火星车静态定姿 = Putting the rover in the proper attitude.
8:14:39 火星车对地通信开始 = Start of rover-to-ground comm.
8:32:04 火星车对地通信结束 = End of rover-to-ground comm.
8:38:04 火星车脱插分离，车体抬升 = Rover separation (from lander?) and body lifted.
8:59:04 火星车太阳翼展平 = Rover solar wing deployed.
9:48:39 环绕器-Z对日姿态调轨开始 = Orbiter Z-axis starts moving toward the sun.
12:00:39 固连遥测探头数据点播下传 = On-demand? telemetry download?
12:29:39 近距离遥测探头数据点播下传 = Short-range telemetry download?
13:15:39 降轨，两器分离数据点播下传 = Decrease orbit, separate the two devices? and download data on demand?

[tolis]

https://mobile.twitter.com/df2mz/status/1393617519257268225

"This screen shot from CCTV seems to show that the Zhurong rover already communicated with Earth, opened its solar panels and downloaded some data." Edgar Kaiser

"rover landed still; started to communicate with earth; communication finished; rover unlocked/lifted up; solar wings opened; obiter adjusted position . Data downloaded in last 3 lines"

Perhaps I am reaching, but is that a picture of a rock up on that screenshot?

[Huguet]

Perhaps I am reaching, but is that a picture of a rock up on that screenshot?

Mabe they are working with some visual data. But they didn't get it right yet. Hard to wait for the images...

[Hungry4info]

It looks like there's some sort of reflecting going on somewhere creating two image planes here -- one being the reflection of the screen in the glass(?) and the other being whatever is behind it. For some reason I can't quite make sense of what's going on. Just below the rock-like shape, there's this white jagged line. Is that a graphical representation of a radio signal? A reflected bit of light from somewhere? I'm not sure which is the original screen (the white line or the rock-like shape) and which is a reflection of something unrelated.

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[djellison]

Both Viking Landers were also deployed from orbit around Mars, like Tianwan - but I think what's unique here, and is more similar to ExoMars-TGO with Schiaparelli, Mars Express with Beagle 2, Galileo and Cassini Huygens compared to Viking - is that in those 4, the 'parent' spacecraft put itself on a collision course before deploying the lander and then doing a divert maneuver. In the case of Viking 1 and 2 - the landers themselves did their own deorbit burn to being entry into the atmosphere.

I think the only unique corner of all those boxes to be ticked yesterday is a parent spacecraft already in orbit putting itself into a trajectory for landing before deploying the lander and then doing a divert maneuver.

Phew.

[Huguet]

Some equalization. First part of the screen seens to have a mars on it. Lest part the strange object and the graphic.

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[serpens]

I wish the Chinese rover the same solar panel cleaning events and longevity as Spirit and Opportunity. Hopefully there will be the same openness with respect to image release.

[marsophile]

I wish the Chinese rover the same solar panel cleaning events and longevity as Spirit and Opportunity. Hopefully there will be the same openness with respect to image release.

I wish the same, but the rover is substantially further north (~25 degrees). I fear it may have more trouble surviving the winter.
cos(2 * 10 degrees) = 0.940
cos(2 * 25 degrees) = 0.643

[vikingmars]

Hopefully there will be the same openness with respect to image release.

Yes : the Chinese said that all images will be availalble for public release. And CNES and ESA will have also an access to them

[Huguet]

"Accroding to xinhua, tiawen is scheduled to do a orbit change at the upcoming periapsis pass. From a 2 day orbit to a 1/3 day orbit."

Tianwen-1 has already changed its orbit, now it appears to be a 1 day orbit, but probably will be changed again for closers and fast ones.

https://mobile.twitter.com/df2mz/status/1393857334955450370
https://mobile.twitter.com/pyr0bee/status/1...854471529123840

[Huguet]

I wish the Chinese rover the same solar panel cleaning events and longevity as Spirit and Opportunity. Hopefully there will be the same openness with respect to image release.

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.

[bobik]

I wish the Chinese rover the same solar panel cleaning events and longevity as Spirit and Opportunity.

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.

[Toma B]

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.

[Hungry4info]

From here:

NASA have three orbiters in place to relay images. China’s only orbiter had to deliver the lander to the surface, escape the gravity back to its orbit (2-day period), change obit/Lower its period to relay lander signal to earth.
An orbit adjustment will be performed today to lower period to 8 hours. Also Zhurong is solar powered, not RTG, the window of opportunities to transmit images is much narrower. So far only sensor and state data were transmitted. Don’t expect pictures till mid week.

[Greenish]

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:

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

[Huguet]

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....

[Huguet]

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

[Explorer1]

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!)

[Huguet]

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

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[djellison]

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!)

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'.

[rlorenz]

n 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....
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

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..)

[Cosmic Penguin]

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'.

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.

[marsophile]

...
In early operations - Spirit and Opportunity survived with just MGS and Mars Odyssey.
...

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.

[vikingmars]

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.




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

[Huguet]

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....

[nogal]

The coordinates have been moved a bit, to 25.1 N, 109.9 E. That moves it out of the CTX image volcanopele posted and puts it about here:

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.




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.

[djellison]

Of course, Spirit and Opportunity did have Direct-To-Earth (DTE) via their high-gain and low-gain antennas.

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

[Huguet]

"#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.

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[marsophile]

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

[Steve G]

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.

[tolis]

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?

[Huguet]

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

[volcanopele]

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.

[Huguet]

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?

[ollopa]

here's an estimate on the landing location using a pair of CTX images

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

[Hungry4info]

From here showing Tianwen-1's new orbit.

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[volcanopele]

They look small sand dunes to me.

[scalbers]

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

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?

[Phil Stooke]

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

[vikingmars]

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.

[nprev]

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

[Phil Stooke]

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

[Cosmic Penguin]

The coordinates have been moved a bit, to 25.1 N, 109.9 E. That moves it out of the CTX image volcanopele posted and puts it about here:




The hills seen in the first orbital image are at lower right.
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.

[Huguet]

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.

[Huguet]

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

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[Huguet]

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."

[ollopa]

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

Nature Astronomy (no firewall)

[djellison]

I used google translator,

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.

[Guest_Steve5304_*]

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

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

[Explorer1]

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....

[djellison]

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

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.

[Huguet]

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

[Phil Stooke]

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

[Cosmic Penguin]

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).

[vikingmars]

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

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

[Huguet]

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).

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

[Cosmic Penguin]

First Photos!

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[neo56]

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

[Cosmic Penguin]

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

It's the complete lander separating from the orbiter.

[neo56]

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