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The Mars Helicopter Is Online and Getting Ready to Fly

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Re: The Mars Helicopter Is Online and Getting Ready to Fly

#151

Post by simonh »

alexvoda wrote: post #138
ericbarrett wrote: post #89

Earlier quoted context omitted.

A consumer chip is a lot more likely to be permanently damaged by a "silver bullet" cosmic ray, though. Rad-hard chips don't just have shielding, they can also have redundant circuits and modifications to the foundry process. That said, I'm sure Ingenuity's processor is fit to purpose.

It's a bit of a shame that radiation hardened chips are stuck so far in the past. I believe the volume is so low it does not warrant the investment to make radiation hardened versions more often.

Actually being stuck in the past might be a feature. Denser circuitry is likely to be more vulnerable to interference by ionising radiation and more vulnerable to physical damage from high energy particles.

Re: The Mars Helicopter Is Online and Getting Ready to Fly

#152

Post by giantrobot »

jefft255 wrote: post #60
nitrogen wrote: post #19

Earlier quoted context omitted.

I had initially assumed that they would be using it for aerial photos to improve navigation decisions. Kind of sad if not.

There absolutely are cameras on board, and yes they are used for navigation. My original question relates more to bandwidth, storage and processing limitation which may mean that we won’t see high quality 30 FPS video.

The Snapdragon CPU has plenty of power for JPEG encoding and likely even hardware accelerated encoders. The 640x480 8bpp navcam images could be entirely usable at a fairly lossy 40:1 compression ratio which ends up about about 8KB per frame, for a 90s flight recording at 10fps that's only about 7.2MB to record the whole flight. It would take a little under 5 minutes to send that back to the rover at 200kbps. The color high resolution camera isn't set up for high frame rate recording IIRC so that was never an option.

High quality 30fps video was never really an option but it's entirely possible/likely to get navcam video after a flight. The Snapdragon is also fast enough to do intraframe compression codec (even h.264) for the navcam video to be able to stream it live back to the rover for relaying back to Earth later like was done with the landing imagery.

The nature of Perseverance relaying through orbiters for high speed uplink to Earth was always going to preclude "live" video from any instrument. The only data important enough for "live" transmission is vehicle telemetry and even then that's only available for the portion of a sol (Martian sidereal day) that Earth is visible from the rover.

Re: The Mars Helicopter Is Online and Getting Ready to Fly

#153

Post by ilamont »

bryananderson wrote: post #131
ilamont wrote: post #18

One of the most significant obstacles for landing on Mars will continue to present problems for our heroic helicopter now that it is safely on the surface. The atmospheric pressure on the surface of Mars is only about 1% that of Earth. Does this also limit the use of parachutes on Mars, or require bigger canopies? I know that Perseverance had a parachute for part of the descent, but not the final landing sequence. II…

Yes indeed. Mars entry, descent, and landing (EDL) is hard. On Earth it’s easy: we can use the thick atmosphere to decelerate to a gentle drop into the ocean. On the Moon it’s easy: the minimal gravity makes powered descent feasible. On Mars it’s hard: too much gravity for an easy powered descent, too little atmosphere for an easy aerobraked descent. Larger spacecraft such as Curiosity and Perseverance (sky crane) an…

Thanks for your reply. I never thought a NASA engineer would answer me, but one of the things that blows me away about this community is truly knowledgeable people are participants in discussions and often weigh in.

Re: The Mars Helicopter Is Online and Getting Ready to Fly

#154

Post by sangnoir »

rhino369 wrote: post #128
tus89 wrote: post #123

Earlier quoted context omitted.

If we understand "flight" as being the use of a wing to generate lift in an atmosphere, then I think we can safely say this is the first time we have flown on another planet. I assume this little helicopter actually has rotary wings rather than fans.

The common understanding of flight definitely doesn't include lighter than air (well atmosphere in this case) vehicles. The first flight was in 1903, not 300 BC China when they used sky lanterns.

Lighter than air is flight - one cannot say dirigibles and hot air balloons are not flying machines.The distinction is made between lighter than air and heavier than air - for which the first was success was by the Wright brothers.

Re: The Mars Helicopter Is Online and Getting Ready to Fly

#155

Post by giantrobot »

EarthLaunch wrote: post #71
NikolaeVarius wrote: post #48

Earlier quoted context omitted.

How many runways do you see on Mars

What if a glider separated prior to the initial main landing? I guess that would increase the risks around the landing.

All that does is complicate the already complicated EDL phase by an order of magnitude.

Trying to launch a drone from the lander during descent would mean:

1) the drone is able to begin its power up process at the end of the cruise phase while the whole probe is buttoned up for reentry

2) the drone has a big enough battery to power avionics, comms, component heaters, and the motors

3) the drone carries a big enough radio and antenna to at least reliably communicate with one of the orbiters relaying data from it and the main spacecraft

4) there's a at least one orbiter positioned to receive data from the drone and the drone manages to perfectly aim its highly directional high gain antenna at the orbiter after an unknown launch position and orientation

5) everything goes perfectly with the drone and it doesn't collide with or damage the sky crane or rover or debris from its launch (or failure) doesn't damage anything

Saying it "increases risks" with the landing is a vast understatement.

Re: The Mars Helicopter Is Online and Getting Ready to Fly

#156

Post by fuzzy2 »

tal8d wrote: post #114
lights0123 wrote: post #82

Earlier quoted context omitted.

> perhaps performance absolutely performance. Yes to the other three for sure, but the engineers reported that there was no way they were running flight control using image tracking on a 200MHz CPU.

Not in python, maybe. Smartbombs have been doing the necessary image processing with much less processing power, on much less capable sensors, for a long time.

Dunno about guided bombs, but cruise missiles have been using some pretty fascinating techniques to navigate before GPS was a thing. It's probably hard to find CPU specs, because they're defense technology.

Re: The Mars Helicopter Is Online and Getting Ready to Fly

#157

Post by mekkkkkk »

johnchristopher wrote: post #7

Will there be a live feed ?

I'm not sure that the drone has an uplink. If not, it would have to relay images to the rover over a 200kbps zigbee connection for transmission. Unlikely to be video in that case, more reasonably highly delayed still frames. Would be more in line with its mission profile as well.
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