The question is like this: The Chinese Mars Orbiter has a HiRes camera on board and I want to know if it is powerful enough to see at least the shadows of the landers and rovers now on Mars.

enter image description here

The high resolution camera of the Chinese Mars orbiter.

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    $\begingroup$ You have presumably seen the pictures from MRO's HiRISE, yes? See phys.org/news/2018-12-mars-insight-lander-images-space.html -The Chinese orbiter has possibly better cameras, so yes, it will be able to see the landers. I'm not sure why you posted numerous pictures of hardware though - they don't assist the question. $\endgroup$
    – Rory Alsop
    Commented Feb 27, 2021 at 10:59
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    $\begingroup$ Later this year we'll learn that the Chinese are actually the first to land on Mars! Their orbiter was capable of seeing the US landers, but it didn't! Darn those crafty NASA folks, if they had only colored in the flames, they'd have gotten away with it! $\endgroup$ Commented Feb 27, 2021 at 14:28
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    $\begingroup$ I removed the "US" from the title to avoid political speculation. $\endgroup$
    – ocirocir
    Commented Feb 27, 2021 at 16:55
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    $\begingroup$ While I understand that many members here have concerns about the tone of the asker's previous questions, this particular question shows improvement. $\endgroup$
    – DrSheldon
    Commented Feb 27, 2021 at 17:04
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    $\begingroup$ ExoMars just spotted it with CaSSIS. Tianwen-1 should be able to see it with its HRC if it overflies the site. However, it's scanning Utopia Planitia quite far away. $\endgroup$
    – Schwern
    Commented Feb 28, 2021 at 0:09

1 Answer 1


Will the HiRes camera of the Chinese orbiter be capable of seeing the shadows of the US landers and rovers on Mars?

tl;dr: Yes it can, IF it passes over one of them, and at the right time of day for shadow-making!

But chances are low that they're going to waste time doing that. They have to put a rover safely on the surface and so they will be targeting potential landing sites on their three low-altitude swingby's per day.

For background have a look at answers to Is the ESA Roscosmos ExoMars Orbiter capable of detecting the NASA landers and rovers on the surface of Mars?

Both Wikipedia and Gunter's Space Page for Tianwen-1 both state that it's HRC (high resolution camera) will have a resolution of 2 meters at 400 km.

eoPortal's page says:

The orbiter is expected to approach as close as 265 km to the surface, allowing a high-resolution camera to return images with a resolution of better than 0.50 meters per pixel.

Which is a lot better than 2 meters at 400 km. It may depend on how resolution is being defined.

It will assume a 256 x 12,000 km (altitudes) elliptical orbit about Mars and carefully study landing sites for the rover.

Here's the original source of your image: Yongliao et al. 2021 Scientific objectives and payloads of Tianwen-1, China’s first Mars exploration mission open access!

The detector of the High-Resolution Imaging Camera (HiRIC) is a TDI-CCD. HiRIC operates in a linear sweep mode to obtain high-resolution optical images of Mars to support studies of topography, geomorphology and geological structure. It provides full-color and spectral images. It has an in-orbit focusing capability.

Before the capsule with the rover separates from the orbiter, HiRIC is used to select the landing area to ensure a safe landing. The main performance parameters of the HiRIC is shown in Table 4.

Table 4. Main performance parameters of the HiRIC.

  • Resolution (at 265 km orbit altitude) Panchromatic: better than 2.5 m, in key areas better than 0.5 m;
  • Color: better than 10 m, in key areas better than 2.0 m;
  • Spectral bands Panchromatic: 0.45–0.9 um
  • color: blue 0.45–0.52 um, green 0.52–0.60 um, red 0.63–0.69 um, near-infrared 0.76–0.90 um
  • Coverage width 9 km@265 km
  • Mass 43 kg
  • Power 127 W
  • Data rate ≤2254 Mbps

So it will be in a long-ish period orbit and only a few times a day swoosh by a certain area as low as 256 km.

IF your favorite "US lander and rover" happens to be there, and IF it happens to be early in the morning or late afternoon, then it certainly has the resolution to see a shadow.

However, unless they are targeting those locations they simply may not pass over any of them.

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    $\begingroup$ I'm surprised by the down vote, this seems to be clear, conclusive, fact-based, well-sourced and correct to me. $\endgroup$
    – uhoh
    Commented Feb 27, 2021 at 11:43
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    $\begingroup$ This is a good, well-written answer. There is no need to down-vote it just because one disagrees with the question asker. $\endgroup$
    – DrSheldon
    Commented Feb 27, 2021 at 16:56
  • $\begingroup$ @DrSheldon: I strongly agree. The person asking the question is, at best, problematic, but the answers have often been good (disclaimer: some of them are mine). Good answers should get upvotes. $\endgroup$
    – user21103
    Commented Feb 27, 2021 at 20:56

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