Can you land a ferris wheel-like ship on Mars ….sideways?

Envision a typical sci-fi ferris wheel kind of spacecraft, with three habitat elements separated from the central hub by girder type booms (attached low on the hub). There would also be triangulating girder stays to the top of the hub, The central hub houses a docking collar, low G work spaces, fuel tanks and rocket engines. All this is pretty standard sci-fi stuff but now I am proposing that you LAND this thing on Mars as total structure.

= The greatly increased moment of inertia due to the large diameter would make for a very stable landing platform (not spinning of course).

= Increased opportunity for aerodynamic surfaces for reentry and landing (along each boom as well as the possibility of sail like membranes between booms).

  • We would have to have landing legs on the habitats as well as the center (engine) unit. (To attempt to put some numbers on this - the landing configuration might be maybe about 180 ft diameter, assuming 50 ft booms, a 30 foot habitat length and a 10 ft radius connection ring at the hub. Of course these numbers are complete speculation and it could be much different. The main point is that it is going to be pretty darn BIG!)
  • The main booms can be telescoping types so that, during the long journey, the habitats can be extended outward for increased pseudo gravity. Assuming 50 foot booms extending three times to make approximately a plus 300’ diameter spacecraft.
  • Habitat to habitat movement could be by small “cars” tethered to the central hub, moving along the perimeter. Airlocks on the cars and habitats make easier transfer possible. Movement to the hub would use the same cars but thrusters would be required to compensate for the speed-up/slow-down while moving radially.
  • The configuration would be robust enough to allow low power course corrections even during spin.
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    $\begingroup$ Spacecraft concepts which either rotate or incorporate rotating elements to produce artificial gravity are typically not envisioned as capable of descent to a planetary surface. They would carry auxiliary vehicles with them for that purpose and only park themselves in an orbit. $\endgroup$ – Anthony X Dec 11 '16 at 1:37
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    $\begingroup$ "typically" not envisioned? So? I think you are missing the entire point of my post. $\endgroup$ – A. Flowers Dec 11 '16 at 2:44
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    $\begingroup$ Nobody has yet figured out how to land a payload on Mars heavier than about a ton/larger than a small car, at least not proven. It's a huge engineering challenge which must be met before Elon Musk's vision can be realized. Mars gravity represents a significant delta-V, and it has an inconvenient atmosphere - thick enough to require heat shielding but extremely thin when it comes to aerodynamic support of any kind.What is currently in development, if successful, could push the limit up to a few tons, but your concept goes orders beyond. $\endgroup$ – Anthony X Dec 11 '16 at 3:23
  • $\begingroup$ So is it the rotating part or (now) the mass that is the problem? $\endgroup$ – A. Flowers Dec 11 '16 at 3:40
  • $\begingroup$ Mass, and mass distribution: you have lots of surface area that all needs to be covered in heat shields, plus a heavy structure that needs lots of rocket fuel to decelerate. $\endgroup$ – Hobbes Dec 11 '16 at 11:55

I'd be tempted to say that this question, as it stands, would be more on topic on Worldbuilding, as it is almost entirely speculative. In reality, no-one would ever want to do this. Let's take it back to basics:

Landing anything on Earth is a challenge. The only large flying objects are Zeppelin type craft, which are buoyant. The largest of which was around 250m long. Down from that the next largest things are jets such as the Antonov 225, Boeing 747 and Dreamliner. These are aerodynamic craft, with wingspan around the 80m mark.

Yes, we can land very small non-aerodynamic craft on Earth - these are capsules under parachutes or using rockets. And they are a huge challenge.

Scale that up and imagine what you need to provide consistent drag/thrust to a large structure without it warping or snapping due to turbulence, especially through that initial move from orbit to entering the atmosphere at sub-orbital velocity, and you'll see one reason why you would never do it.

Now think about doing that millions of miles away on Mars...

Another reason is that it has no benefit on a planet. Rotation is useful in space to supply an artificial gravity equivalent, but not for any other reason, or in any other environment. If you build it in space, you'll want to keep it in space.

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  • $\begingroup$ Thanks for the link to Worldbuilding. I’m new here and hadn’t seen that part of the site. It looks interesting. As you wrote, rotation is good for the trip to Mars. If LANDING the whole thing is smart, I don’t know. I am not necessarily proposing it, but asking about feasibility. I do see possible benefits in a lander with a big footprint and high polar moment of inertia. A larger heat shield area might be a benefit. Also, it would bring a LOT of stuff down in one swoop. I certainly don’t see this idea for initial flights. Of course if it breaks up, that isn’t so good.! $\endgroup$ – A. Flowers Dec 11 '16 at 16:41
  • $\begingroup$ WorldBuilding is really good for certain types of question, and the hard-science tag is excellent for getting some specifics. $\endgroup$ – Rory Alsop Dec 11 '16 at 17:04
  • $\begingroup$ I can imagine a very good reason why you would want to do this - you do all of the work constructing the habitat in Earth orbit, where you have (relatively) ready access to aid and resources. The you land the hab on Mars, complete with all of the infrastructure entirely intact. The big problem is that the gravity orientation is now rotated 90 degrees from the outer rim of the wheel to or the other side. $\endgroup$ – Chris B. Behrens Dec 25 '16 at 4:21
  • $\begingroup$ The problem as the poster mentions is aerodynamics. You'd have to be so rich in thrust that you could afford to decelerate without aerobraking. If you're that rich in propulsion technologies, you're probably less worried about building stuff on Mars. $\endgroup$ – Chris B. Behrens Dec 25 '16 at 4:22

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