Chinese Mars Mission

[Infinitesky]

apparently there are also two competing designs, one from SAST and one from CAST. rumors say that the CAST proposal was the winning one

Even whether SAST or CAST have had more than one design solution.

CAST (2011)


CAST (2014)



CAST (2016)


SAST(YH-1 modified version)


SAST (2013)



SAST (2015)







I personally think that the design of SAST is more ugly, SAST design was first improved from the YH-1（China's first Mars probe, failed with Russian rocket in 2011）, and now it is closer to the design of the CAST, lander from experimental small EDL into a large EDL with a rover.

[Star One]

That's quite a radical overhaul in design over just two years.

At first, Mars mission was not approved until a few days ago.
So in the early pre-research, change is normal (I think the rover just looks like be amplified).
The new design film was shown to the government on 19th January and named as "Explore&Start".
After that, it was officially confirmed during the two sessions（NPC &CPPCC）.

Thanks for that explanation.

[Infinitesky]

The new article from Xinhua news agency, I simply translate.
compared to the Jade Rabbit（Yutu）：
The area of the solar panels on the Mars rover will be much larger (the same area of the solar energy is only 40% of the moon's surface).
When the sandstorm comes, it will sleep (when sandstorm occurs, because of the sharp decline in Mars rover receiving of solar light energy, aerospace experts think must design a "sleep" mode for the rover）
The body is stronger (the gravity on the surface of Mars is heavier than the moon).
More intelligent (due to the delay of communication between Earth and Mars, a lot of tasks must be decided by itself).
In general,it is close to the "Spirit" and "Opportunity" in the volume, weight, and technology level.Using solar power, rather than the "Curiosity" of the nuclear battery.
The article also uses nearly half of the length to explain why we should go to Mars and do other deep space exploration, which shows that there are still doubts and resistance in the ordinary people.

http://dy.qq.com/article.htm?id=20160317A06R3800

[the_other_Doug]

Fascinating that the back-and-forth translation morphs the name of the MER "Spirit" into "Courage"... 

[Infinitesky]

Fascinating that the back-and-forth translation morphs the name of the MER "Spirit" into "Courage"... 

I'm sorry I forgot. I'll correct it.

[Nordren]

Xinhua has now translated that piece with Ye Peijian and Jia Yang into English: http://news.xinhuanet.com/english/2016-03/21/c_135209176.htm

"Unlike the lunar lander of the Chang'e-3 probe, the Mars lander will carry a gasbag, a parachute and reverse thrust engines, which will together secure a safe landing, according to experts from CAST."

"The Mars rover should be able to sense the environment, plan its route, conduct scientific exploration and detect faults autonomously. It should be a mobile intelligence."

[Infinitesky]

The probe will be in an elliptical orbit and the rover's landing position is not selected.

[Dalhousie]

The probe will be in an elliptical orbit and the rover's landing position is not selected.

Very Viking like in operation.  Will be lander be released prior to or after MOI?

For a start they could do worse then look at the MER, MSL, ExoMars, and 2020 mission landing site proposals, many of those not selected are still very interesting sites

[Infinitesky]

The probe will be in an elliptical orbit and the rover's landing position is not selected.

Very Viking like in operation.  Will be lander be released prior to or after MOI?

For a start they could do worse then look at the MER, MSL, ExoMars, and 2020 mission landing site proposals, many of those not selected are still very interesting sites

I guess before that, you can refer to those pictures released before.
Otherwise it will consume more fuel to change the orbit, because the total quality of probe and lander will reach more than 5 tons.
In fact I think it is risky to launch the probe and the lander at the same time in the first mission.
Because there is even no high resolution Mars map available for landing(Unlike the lunar exploration project).
But there is no choice, they must achieve more goals in a limited budget(In 2009, they had hoped to launch a probe in 2013 with LM3B, but the proposal has not been passed).
Perhaps they will learn more from the experience of MER, MSL, and ExoMars.

[Dalhousie]

The probe will be in an elliptical orbit and the rover's landing position is not selected.

Very Viking like in operation.  Will be lander be released prior to or after MOI?

For a start they could do worse then look at the MER, MSL, ExoMars, and 2020 mission landing site proposals, many of those not selected are still very interesting sites

I guess before that, you can refer to those pictures released before.
Otherwise it will consume more fuel to change the orbit, because the total quality of probe and lander will reach more than 5 tons.

Which is why Viking was so massive of course.

In fact I think it is risky to launch the probe and the lander at the same time in the first mission.
Because there is even no high resolution Mars map available for landing(Unlike the lunar exploration project).
But there is no choice, they must achieve more goals in a limited budget(In 2009, they had hoped to launch a probe in 2013 with LM3B, but the proposal has not been passed).
Perhaps they will learn more from the experience of MER, MSL, and ExoMars.

Image coverage of Mars is very good. Even ignoring the low resolution stuff (TES, THEMIS, Viking, Mariner 9 MOC and HiRISE context images),we have near global HRSC coverage (~10 m), plus about a decade each of MOC (1-4 m) and HiRISE (30-30 cm) imagery of a great many specific targets.  Something like 70 landing sites were proposed for the MPL/MER/Phoenix/MSL/ExoMars 2016/ExoMars 2018/Insight/2020 missions, each with extensive MOC and HiRISE coverage. Many landing sites that miss out one one mission get recycled for later ones. Melas Chasma was considered for both MER, MSL, and now 2020, for example. 

Of course the engineering and trajectory characteristics of the Chinese lander might rule out many of these, but may also open up some new possibilities.  Mission planners may of course want to make their own selection from first principles.  There are many areas with quite extensive MOC and HiRISE coverage that have yet to be considered as landing sites.

[plutogno]

Very Viking like in operation.  Will be lander be released prior to or after MOI?

I guess before that, you can refer to those pictures released before.

I remember seeing a few references (conference papers, mostly) where the lander would be released Viking-like after MOI

[Dalhousie]

Very Viking like in operation.  Will be lander be released prior to or after MOI?

I guess before that, you can refer to those pictures released before.

I remember seeing a few references (conference papers, mostly) where the lander would be released Viking-like after MOI

Do we know if NASA/JPL would accept HiWISH image requests from Chinese researchers?

if not, and they decide to go somewhere new, then maybe it would make sense to release the lander after MOI and acquisition of some high resolution images with an onboard (MOC level) camera.  Do we know yet whether the orbiter will carry a camera of such resolution?

But IMHO there would have to be some compelling reason do do this, rather than choosing from the abundance of interesting sites already delineated.  Even restricting ourselves to rover sites, more than 50 have been reviewed.

[notsorandom]

Very Viking like in operation.  Will be lander be released prior to or after MOI?

I guess before that, you can refer to those pictures released before.

I remember seeing a few references (conference papers, mostly) where the lander would be released Viking-like after MOI

Do we know if NASA/JPL would accept HiWISH image requests from Chinese researchers?

if not, and they decide to go somewhere new, then maybe it would make sense to release the lander after MOI and acquisition of some high resolution images with an onboard (MOC level) camera.  Do we know yet whether the orbiter will carry a camera of such resolution?

But IMHO there would have to be some compelling reason do do this, rather than choosing from the abundance of interesting sites already delineated.  Even restricting ourselves to rover sites, more than 50 have been reviewed.

They are not going to be able to get imagery with a high enough spatial resolution to retire all the risk of hazards at a landing site. Only a sensor like HiRISE can resolve those objects. The second best sensor to be orbited around Mars was the Mars Orbiter Camera on MGS. It could resolve 1.4 meters but that wasn't good enough to spot smaller rocks which would be a hazard. Indeed Mars Phoenix was re-targeted when HiRISE showed an unacceptable rock count that MOC missed at its initially preferred landing site.

There are two reason I don't think they will get that HiRISE equivalent imagery. First is that HiRISE is a big sensor with an aperture of 50 cm and a mass of 64.2 kg. I'm not seeing an instrument that size on any of the notional models or pictures of the Chinese orbiter. Secondly the note about the orbit being elliptical would preclude the probe from being at an altitude conducive to mapping. Even if HiRISE were on this orbiter it would spend most of the time too far away from the martian surface to gather high resolution imagery.

You brought up the landing sites investigated for previous US landing missions. These areas have been extensively mapped at high resolution and those images are on the freely accessible Planetary Data Server. There are two reasons that these areas were not selected, they were dangerous to land in or they were not as interesting scientifically. The Chinese have been operating their exploration program more as an engineering test program than a scientific one. A safe but less interesting site may be seen as just fine for their first lander.

[Dalhousie]

They are not going to be able to get imagery with a high enough spatial resolution to retire all the risk of hazards at a landing site. Only a sensor like HiRISE can resolve those objects. The second best sensor to be orbited around Mars was the Mars Orbiter Camera on MGS. It could resolve 1.4 meters but that wasn't good enough to spot smaller rocks which would be a hazard. Indeed Mars Phoenix was re-targeted when HiRISE showed an unacceptable rock count that MOC missed at its initially preferred landing site.

While the higher the resolution the better, you don't need HiRISE. The Vikings and Pathfinder landing sites were chosen without any high resolution imagery. The MERs were chosen with MOC.  There are other data that can be used to minimise risk. Thermal intertia, radar scatterometry and polarimetry.  All publically accessible data, as you correctly point out.  But even if you want only HiRise documented sites there are a huge range of these to choose from.

There are two reason I don't think they will get that HiRISE equivalent imagery. First is that HiRISE is a big sensor with an aperture of 50 cm and a mass of 64.2 kg. I'm not seeing an instrument that size on any of the notional models or pictures of the Chinese orbiter. Secondly the note about the orbit being elliptical would preclude the probe from being at an altitude conducive to mapping. Even if HiRISE were on this orbiter it would spend most of the time too far away from the martian surface to gather high resolution imagery.

I think you are probably right on this.

You brought up the landing sites investigated for previous US landing missions. These areas have been extensively mapped at high resolution and those images are on the freely accessible Planetary Data Server. There are two reasons that these areas were not selected, they were dangerous to land in or they were not as interesting scientifically.

It's not as simple as that.  Some sites were indeed dropped because they were deemed too risky at the time.  Others because they were considered less interesting.  However a great many excellent sites were dropped for really trivial reasons.  The process is all documented, there are many sites that remain valid, especially at the round, but because you have to choose one site out of four, three have to be dropped.

Circumstances change.  More data, better modelling may render a site previously considered unsafe to be suitable.  Improved technology may make a previously marginal site accessible - Gale crater for example, rejected for MER but chosen for MSL. New information comes comes to light and sites not previously considered get added.  Gusev crater was not a candidate initially for 2020, but because of new data was added at the second meeting.

The Chinese have been operating their exploration program more as an engineering test program than a scientific one. A safe but less interesting site may be seen as just fine for their first lander.

First of all the engineers always win, all the landing sites have to be safe.   This is true for ESA and the US as well as China.  Secondly it's wrong to imply that science is not a driver for Chinese target selection, all Chinese lunar and planetary missions have had science drivers, and extensive results.

[Infinitesky]

Roadmap for Chinese deep space exploration presented at #LPSC2016. Mars mission in 2020 approved by Chinese govt.




The latest news shows that probe will enter MOI first, and then release the lander.


2020: Launch of Mars probe and lander.
2023-2024: Launch of asteroid probe.
2028-2029: Mars Sample Return mission.
2030：Launch of Jupiter probe.


(It is said that in the initial plan, there are 9 projects, and now only 4.)

[Star One]

I am happy to see the Jupiter probe is still in there. Is that going to be touring the Jupiter system like Galileo?

[Infinitesky]

I am happy to see the Jupiter probe is still in there. Is that going to be touring the Jupiter system like Galileo?

I hope the reason why the launch is so late is because the mission requires heavy rocket LM9, so that they can launch a huge and complex(also expensive) probe (contains some sub probes).

[Star One]

I am happy to see the Jupiter probe is still in there. Is that going to be touring the Jupiter system like Galileo?

I hope the reason why the launch is so late is because the mission requires heavy rocket LM9, so that they can launch a huge and complex(also expensive) probe (contains some sub probes).

Do we know what the LM9's capability is as far payloads to Jupiter?

[Infinitesky]

Do we know what the LM9's capability is as far payloads to Jupiter?

We do not know, because LM9 is still in design and has not been officially approved. It is said that its LEO capacity can reach 100 tons or 130 tons (similar to SLS or Saturn 5)
But I think it is maybe difficult to complete its first flight before 2030.

[shooter6947]

While the higher the resolution the better, you don't need HiRISE. The Vikings and Pathfinder landing sites were chosen without any high resolution imagery.

Yeah, you pretty much do need HiRISE to be sure that your selected site is safe.  The Vikings worked basically because they got lucky.  See this discussion of the Viking landing site selection process for details.

Of course you can always just roll the dice and hope for the best, if you don't NEED to be SURE.