The Curiosity rover landed on Mars using an extremely complex system, system involving a sky crane and using pictures from the orbiter to maneuver to a flat landing spot. The 1 ton car (equivalent to 300 kg in Mars' gravity) was suspended from a hovering rocket platform, after parachute deployment (where the atmospheric density is 1% of Earth's). All this was done automatically since signals from Earth take too long to control the process.

The complex process is animated in this Jet Propulsion Lab video of the landing.

Such a complex system must have been tested extensively. But I have seen no video of testing on the Earth.

Videos from testing only show extremely simple procedures in the lab. Like the Sky Crane Full Motion Drop Test. That is the most complex test I have found. It was considered the major test and all staff was called in. That is not enough to risk billions of dollars sending it to Mars.

Nature World News quotes a "truther" who in turn attributes to others the idea that the landing was a fake:

He claims that there is a growing rumor that says NASA did not even send a rover to the red planet and the images and footages being released were filmed in Canada, according to a report.

Did the rover land on Mars?

  • The system is so complex that it must have been tested extensively on earth. But no video exists from that testing. (The videos that exist only show extremely simple procedures in the lab.) You can not design such a complex system and send it off to Mars without extensive testing.
    – KaE
    May 4 '20 at 10:52
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    I should actually have emphasised my second question: is anyone else claiming that the Curiosity landing was faked? Questions here require a specific notable claim; i.e. a claim that's widely believed or has been made by a notable individual. If this is your own speculation, and not something that's widely-believed or promoted by a notable individual, then I'm afraid it's off-topic here.
    – F1Krazy
    May 4 '20 at 10:56
  • Wow! To accept testing of skeptical statements, they must be widely believed. Considering the bias in Google, I wonder what kind of questions will be accepted here.
    – KaE
    May 4 '20 at 11:03
  • Widely believed or made my a notable individual. If you can find a link to someone else claiming that the Curiosity landings were faked, and demonstrate that they're notable in some way (i.e. not just a random social media account), then this would be on-topic.
    – F1Krazy
    May 4 '20 at 11:06
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    I was lucky here is an article
    – KaE
    May 4 '20 at 11:09

Did you ever see a video of a proto-boeing-787 flying before the testbed version of a boeing-787 flew? No, you didn't. Why not? Here's a craft that is designed to fly in earths atmosphere, and they never even tested it before building it!

The answer is that computers and wind tunnels are fantastically good at reproducing the behaviour and environment of flight envelopes, so there is just no need to build a huge physical prototype outside of perhaps scale models for use in wind tunnels (even that is done by computer now).

Why do I talk about aircraft? There is a strong link between aviation and spaceflight, hence the name aerospace. A different atmosphere, a different environment, but that's just variables in a computer simulation.

As an aside, anyone who has ever played Kerbal Space Program can attest to just how realistic a "simple" game can be in reproducing most of the complexities of space flight and interplanetary travel/landing.

Back to Curiosity, there is a great youtube video which describes the process used to land Curiosity, it's the first 5 minutes, well worth a watch.


But you're right, it never shows a trial on Earth, and why would they? It's a different atmosphere, it would be hugely costly to take it to lower earth orbit only to drop it back down again in the wrong environment. And once again, a computer simulation can do it much better, and for a fraction of the cost.

All in all, as with any conspiracy theory we need to apply Occam's Razor. What's the simplest explanation? Did they:

  • Fake the actual rover
  • Fake taking it to Mars
  • Fake land it
  • Fake every picture and scientific discovery
  • Silence all the thousands of engineers, scientists, mission controllers, etc etc
  • Silence their critics (who would love to shout about how much of a waste of money space exploration is)

or did they:

  • Use some really smart people
  • Use some cool technology
  • Actually land a small-car-sized bit of tech on Mars

It's actually simpler to just do it for real!

  • They flew the lunar landers on earth. Much simpler technology than Curiosity "sky crane".
    – KaE
    May 4 '20 at 12:03
  • 2
    @KaE Computers and wind tunnels were nowhere near as sophisticated back then, so they didn't have a choice.
    – F1Krazy
    May 4 '20 at 12:06
  • Considering the cost of failure, after launching it to Mars, my opinion is, you fly Curiosity on earth. They showed other, very simple testing but no flight.
    – KaE
    May 4 '20 at 12:12
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    @KaE they never flew the actual lunar landers on earth. They flew test machines to verify certain of the design ideas, that's all.
    – jwenting
    May 4 '20 at 14:06
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    @KaE, that's an LLRV, basically an Earth-based flight simulator for the Lunar Module. It's designed to give a pilot the feel of flying on the Moon, not to test the flight dynamics of the actual Lunar Module.
    – Mark
    May 8 '20 at 0:57

In my experience most testing isn't particularly exciting and worth recording and sharing with the public.

Nevertheless, the NASA shared a lot of videos and photos showing the more visually interesting aspects of the Curiosity rover being tested:

So, the contention that the complex system was untested because there is no evidence of testing is untrue.

  • 2
    "So, the contention that the complex system was untested because there is no evidence of testing is untrue." Rather, there is a bunch of evidence, just not video evidence. Still, great answer!
    – T. Sar
    May 4 '20 at 15:05
  • The question mainly refers to the landing and the "sky crane". The flying landing platform, searching for flat terrain, roping down the car is far more complex than the procedures documented. The main testing documented was Sky Crane Full Motion Drop Test. It is not enough to only do this to risk millions to.send it to Mars. The flying landing platform was not tested and documented
    – KaE
    May 4 '20 at 17:24
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    @KaE you realise that "risking millions" is like you risking a £100 punt on the Horses. They have budgets measured in hundreds of millions.
    – Jamiec
    May 4 '20 at 17:32
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    @Jamiec: NASA budged is $22 billion / FY. The Curiosity budget was apparently $2.5 billion.
    – Fizz
    May 4 '20 at 20:25
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    "The flying landing platform was not tested and documented" I would reword that: The tests of the flying landing platform were not video recorded, edited into an easily digestable and exciting video for the public (and funding granters) to watch, and then uploaded to a location easily found. Concluding that, therefore, there were no tests is unjustified. Concluding from that alone that the landing was therefore faked is... I want to keep this polite.... also unjustified.
    – Oddthinking
    May 5 '20 at 3:01

Do you realize Curiosity has been on Mars and sending data ever since then? Do you think that if they were hiding it in Canada, there would be no kink in this story for nearly 8 years?

Are you saying all those photos movies from Mars (which NASA says were sent by Curiosity) are fake/CG? (Including the one with the flapping parachute on landing?) And if all those are [easy to] fake, what would a single [extra] test movie on earth prove?

Note that the Curiosity parachute, which was considered (quite) critical was extensively tested, but mostly in a wind tunnel because dropping it from a helicopter [which was done] turned out to be less informative as filming it at high speed (and up close) was the most important info collected. (Even for the newer 2020 rover [named Perseverance], a single real drop test of the parachute was performed--and not with the actual rover as load--because of the 100-fold difference in atmospheric density between Mars and earth.)

For the [Curiosity] crane retro-landing stage

Still, a real-world sky-crane landing has never been attempted, even on Earth.

"After extensive discussion, it was determined that the modifications needed to perform such a test in Earth gravity and atmosphere would result in extremely limited value from the test," Rivellini said. Mars's gravity is about a third that of Earth, and its atmosphere roughly 99 percent thinner.

So the radar that controlled when the rockets are fired was tested separately. The whole Curiosity retro-landing system was only simulated.

And that was indeed a chance they took. The same article discusses how Beagle 2 presumably failed to land properly although more recent data suggests that it failed to deploy properly (its antenna and/or solar panels) after landing. In general, the success ratio of lander missions to Mars hasn't been so good: "Two thirds of all landers sent there have crashed or lost contact with Earth, and half of the missions launched haven’t made it to the planet at all."

There a more in-depth Nat Geo video that discusses why the traditional alternatives (airbags, leg lander) were rejected for Curiosity. The 2020 rover will also use a sky crane, so I guess we'll find out how lucky the solution is/was. There was a separation test for the 2020 rover, but no real drop test, as far as I can tell (let alone one in which the retro rockets fired).

The much older Viking program also used retro-rockets to land on Mars, although not detachable ones (i.e. no crane, since the Vikings didn't have wheels so there wasn't a worry that the rockets can become entanglement points later). You might want to inquire about this further on Space SE, but it looks like a full landing test wasn't performed on earth for those either, only separate parachute (p. 11) or drop tests for the legs (p. 39) etc. Actually (p. 40) they did conduct four high-altitude tests (at 36 to 43 km high in earth's atmosphere) for the Viking vehicle's initial deployment of parachute etc. And a landing shock (drop) test for the fully assembled Viking lander was conducted 3 times (p. 48), but not with the retro rockets fired, but simply dropped from a height that would simulate its designed landing velocity. (This is quite similar to the video you saw for Curiosity). Additionally for Viking they conducted "pyrotechnic shock tests" to verify that nothing (internal) was disturbed by the firing of the rockets, but no actual landing under rocket power as far as I can tell.


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