Helicopters for Mars exploration

On Friday, January 30, 2015 at 6:45:08 AM UTC-5, wrote:
Some of the Curiosity descend camera high res images are still
on Mars.

Tell me more. Someone remind me of the position of the descend camera. Was it on the rover or the aeroshell? Are you saying that these images were recorded on the rover and just never uploaded?

Dave

On Tuesday, February 3, 2015 at 3:13:29 PM UTC-5, David Spain wrote:
On Friday, January 30, 2015 at 6:45:08 AM UTC-5, wrote:
Some of the Curiosity descend camera high res images are still
on Mars.

Tell me more. Someone remind me of the position of the descend camera. Was it on the rover or the aeroshell? Are you saying that these images were recorded on the rover and just never uploaded?

Dave

Not aeroshell, I meant the Skycrane rocket platform.

Dave

On Friday, January 30, 2015 at 6:45:08 AM UTC-5, wrote:
http://www.cnet.com/news/nasa-propos...s-rover-scout/

A helicopter on Mars would have supersonic flow

No it wouldn't. NASA has tested helicopters in a 600 Pascal CO2 atmosphere and they obtain efficient lift at 40 ms. 1/10th sound speed.

and therefore be
inefficient.

Wrong on two counts.

(1) The rotor is not supersonic, it operates at Mach 0.1
(2) Supersonic fans are 85% efficient, not materially less efficient than subsonic.

http://www.enginehistory.org/Allison...ropulsion.html

Low payload,

Define 'low' - fact is, autonomous flight systems as little at 100 milligrams have been built and flown. A 2 kg system designed by NASA is loads of capabilities when working with a ground based rover.

much complicated to operate.

Again, define your terms. What spacecraft or space mission is NOT complex? All are. Quadrotors are already flying on Earth, and small flight systems have been tested under martian conditions ON EARTH - where the gravity is 3x greater!. There are no show stoppers, and many advantages;

(1) speed,
(2) range,
(3) obstacle avoidance,
(4) improved planning (you can see farther),

With the low
density of Mars the favor is on something else:

The density of Mars' atmosphere is sufficient to create helicopters that fly on Earth. They can lift three times this weight on Mars.

http://www.jpl.nasa.gov/news/news.php?feature=4457

A high tower with a
long lens camera system on top. Even at a Martian storm the wind
force on such a structure is low.

A rover with a selfie - that's a good idea. Its not an argument against helicopters, since a rover can have both.


Think about a low weight inflatable / extendable / (printed ?) structure.
Not an easy task to develop.

Especially if you don't have a clear idea of what you mean.

But such a camera could scan a large area

Well, the density of the Martian atmosphere is very low. A balloon would have to be rather large, and heavy, and subject to winds - a large number of small solar powered helicopters makes more sense actually. Though balloons would be favoured in Earth's dense atmosphere and high gravity.

A tethered balloon might be interesting. I don't think its better than a large number of small helicopters, and you could foul in the tether and a wind could drag your rover to a spot it couldn't escape.

in high resolution. It would be close to a CPU for preprocessing.

You know that ICs are on the nanoscale today and weigh micrograms don't you?

There
are algorithms able to find fossils.

There are algorithms that reason and write better than you do.

And of course movements like from
dust devils or water eruptions. Selected images would be send to Earth
and the rest stored for some time.

You do know that quadrillions of bytes of data can be stored in milligram sized systems don't you?

The bottleneck for any such Mars
mission is the limited transmission capacity to Earth,

You do know that gigabit laser communications with Earth has already been achieved don't you?

http://www.space.com/534-nasa-test-l...pacecraft.html

not the camera
capacity.

You know that HDTV signals using MPEG2 format operate at 19.3 megabits per second and that laser communications with mars operates in the gigabit range don't you?

Some of the Curiosity descend camera high res images are still
on Mars.

Which ones?

http://phys.org/news/2012-08-curiosi...le-crater.html

There are photos missing from various mosaics, but that doesn't mean it was due to bandwidth. They may have been missing because they weren't taken, or were lost due to data corruption.

It is an interesting issue. Of course, Curiosity does have a laser scanner that can be adapted to laser communications. However, its primary transmission is more limited than an ideal laser system would allow.


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