New skycrane variant from ESA

[hyphon 10]

Hello everyone,

I just found a news in one of my favorite German astronomy and space science blogs, about a skycrane module developed by the ESA.

Unlike the NASA model, it's a so called "DROpship quadrocopTER" short "Dropter", using 4 double-propeller attached to tiltable engine nacelles, instead of rocket-powered engines. Actual the dropter is still in development a working model was just tested for prove that the onboard software is able to autopilot to a predefined GPS waypoint, searching for a safe place to unload it's rover payload via a cable on the ground and reach a safe height after the rover is released. Would be nice to have something like the dropter as a skycrane for medium rover's.

In the comment section of the blog mentioned above, people are discussing if a propeller-driven engine would work in the Mars' atmosphere, because of the low pressure.

But here's the link to the ESA news:

http://www.esa.int/Our_Activities/Technology/Dropship_offers_safe_landings_for_Mars_rovers

Would be nice to hear your opinion on this.

Edited July 9, 2014 by Hyphon

[dram 14]

Cheers for the link! That's a very interesting read. I expect it could work on mars but would require much, much larger propellers and thus body to function correctly in the thin atmosphere. You could reduce the size if you up the RPM of the blades.

[hyphon 10]

We discussed this on that blog I mentioned in my starting post. I suggested to ad more blades and change the type of the propellers to ducted fan propellers.

Even it needs more power and increases weight, the additional lift would be useful in Mars' thin atmosphere.

Additional it could be used as reconnaissance aircraft, to spot science points.

With the size of the propellers. They used a modell sized 1 meter in diameter. The propellerblades have a length of 0.41 meter.

I think they plan to drop rovers like Spirit/Oppertunity. Rovers like Curiosity would be far too heavy and too big for a propeller based system in Mars atmosphere.

Edited July 9, 2014 by Hyphon

[wesleybruce 1]

Rotor diameter would be a problem. Due to the low pressure a rotor on mars would need to be about 6 times the diameter of the one on earth. That makes the boom arms 6 times longer etc, etc. The whole thing becomes a spindly fragile leaf. NASA also used quadcopters to test the idea and all the non rocket components so this is not new. Remember if you send something to mars the launch forces will crush anything too fragile. You also need to fit whatever you send to mars behind a compact heat shield. You need to fold everything up into a ball and have it unfold first time every time. That's hard. 

 

However adding a parafoil to the top of a quadcopter and a despin hub below may allow you to do a cable and bucket delivery: Bucket drop. The parafoil flies a big circle high with a long cable to the ground. The despin hub negates the spin or tangling on the payload. A bucket on such a system was lowered to amazonian indians moved so slowly that things could be removed and replaced in the bucket and that was with a relatively fast cessna at the top of the line. Sadly, the inventor, Nate Saint, a missionary, was later murdered by some of those indians. The son Steve Saint also makes and sells a flying car. Here is Steve Saint doing a bucket drop demonstration a few years ago.

 

 

 Essentially a bucket drop is a monowing helicopter. No one has tried a slow parafoil yet. Add a few small control thrusters on the 'bucket' and you have very precise 'bucket' positioning. 

[wesleybruce 1]

Another landing option that would work on mars is an aerostatic wing craft. The wing is a hydrogen filled balloon or inflatable lifting body. Inflate it using a chemical cartridge as the craft descends on a normal parachute. Because the wing has no weight in the atmosphere it can be very big and slow. Because it's aerostatic wing stays aloft above the landed payload it can take off and land freely. Very good for exploration. Hydrogen will leak out slowly so I won't last forever. It's particularly good for venus because you can harvest hydrogen from the acid clouds with a little fancy chemistry.