JPL's Plan for the Next Mars Helicopter • Hacker News Board

Re: JPL's Plan for the Next Mars Helicopter

#111

Post by dogma1138 » Thu, Aug 12, 2021, 5:34 PM UTC

jvanderbot wrote: post #68

dogma1138 wrote: post #56

Earlier quoted context omitted.

Just thinking about some solutions - origami of both load baring hard materials and connecting flexible ones, or even do something whacky like have a composite fabric balloon that you inflate and the impregnate with resin insitu then when the resin hardens you have a large shell that can be emptied to create a vacuum.

Put rough numbers to it to check feasibility and submit: https://www.nasa.gov/directorates/spacetech/niac/index.html At least one "garage engineer" was selected this last round.

Someone else already did https://core.ac.uk/download/pdf/161998356.pdf

Re: JPL's Plan for the Next Mars Helicopter

#112

Post by dogma1138 » Thu, Aug 12, 2021, 5:37 PM UTC

jbay808 wrote: post #49

dogma1138 wrote: post #32

Earlier quoted context omitted.

I was thinking about a rigid body vacuum airship, landing would be easy because all you need to do is lose the vacuum which can be done with a valve and cost no power. Taking off again can be done over days so you can power it with solar panels if you can’t fit an RTG. I honestly don’t think winds would be that much of an issue they won’t be strong enough to structurally damage the airship they’ll blow it off sure bu…

I'm not aware of any vacuum container that is strong enough to resist buckling while being light enough to be buoyant.

https://core.ac.uk/download/pdf/161998356.pdf

They found a design that can work with current materials and lift 500kg worth of payload.

>”The tensegrity based design using current materials, accounting for losses due to deflection of the membrane and other factors, is capable of 500 kilograms of payload. If trends in the mass reduction capabilities of the tensegrity beam design continue to higher complexities, which is probable, then implementation of a complexity 4 beam will result in 1 to 1.5 tons of payload capacity. In addition, the tensegrity design has been shown to offer full deployability and can be collapsed for transport to Mars.”

Re: JPL's Plan for the Next Mars Helicopter

#113

Post by arhpreston » Fri, Aug 13, 2021, 2:28 PM UTC

MichaelZuo wrote: post #108

arhpreston wrote: post #104

Earlier quoted context omitted.

If you're interested in the details of what goes in to developing rotors for a helicopter for an atmosphere we've never built in before you should check out this talk: https://doi.org/10.52843/47ly7q

Thanks! In scaling up the fragility of the material seems very likely to be a big factor, cube-square law and so on. I wonder if there’ll be physical testing of proposed designs, are there even near-vacuum wind tunnels?

A lot of that talk compares theoretical results with experiments in a low-pressure wind tunnel (see e.g., the slide at this point https://cassyni.com/events/6GYLBKG5pBd4su8dm9A9FB?t=255.0s for a reference).

It's quite a simplistic (2d) setup however. I'm not aware of any more complex experiments.

Re: JPL's Plan for the Next Mars Helicopter

#114

Post by bobsmooth » Mon, Aug 23, 2021, 11:09 PM UTC

sennight wrote: post #110

bobsmooth wrote: post #109

Earlier quoted context omitted.

There are billions of ARM processors used in a wide range of applications. How many radiation hardened CPUs are in use today? And the one of the goals of Ingenuity was to see if a COTS processor could be used on Mars. The fact that it's survived this long is really encouraging.

> How many radiation hardened CPUs are in use today? Whoosh. A radiation hardened PowerPC 750 operates no differently from a PowerPC 750 you'd find on Ebay. You are effectively saying "Yeah, but how many commercial temperature range processors are in use today?!" It is weird, because it is such a silly distinction to point to that you have to actually examine the manufacturer's packaging datasheet to spot the differe…

>A radiation hardened PowerPC 750 operates no differently from a PowerPC 750 you'd find on Ebay.

The RAD750 costs $200k. I doubt the ARM processor in Ingenuity costs that much.

>Do you really want to see that trend go beyond crappy cellphones designed to be thrown out every other year?

I want cheaper rovers and probes, this is NASA's test for viability

>with regard to the effects of radiation on electronic.

You can test shit in the lab all day but eventually you have to test in the field.

>Does Mars have some new kind of radiation that our highly controlled labs can't replicate?

Do we know exactly the levels of radiation on the surface?

>Of course not, it is a nonsensically wasteful way to test our understanding of radiation - at best.

It's a live, in the field test of off-the-shelf components in space craft on a bonus mission unrelated to the main rover. What would be a sensically nonwasteful test of COSTS processors on Mars be?

>the processor has no way of self diagnosing internal faults caused by ionizing radiation

The helicopter flies and takes pictures. It's had 12 flights as of this comment. When it stops working, we'll know how long regular processors can last.