The Mars Helicopter Is Online and Getting Ready to Fly • Hacker News Board

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

#31

Post by dogma1138 » Sun, Feb 28, 2021, 5:56 PM UTC

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…

Both, but the main limit of a parachute is that our probes don’t go into orbit first but rather crash on Mars.

So you enter the atmosphere at higher than orbital speeds. From orbit a parachute might be doable despite the relatively thin atmosphere.

Stationary probes can use retro rockets to land because you don’t care about their stationary mass that much.

For rovers it’s more tricky so you have to either use airbags like the smaller rovers did or a propulsive landing like Percy/Curiosity.

The sky crane was chosen as the method for those because they are too massive to do a cushioned crash landing and they won’t be likely able to move with the weight of the propulsive landing system so we have to ditch it.

The sky crane is basically the worlds most expensive bungee jump.

The rockets on the sky crane bring the rover to hover and then it drops to the ground on a set of arresting cables.

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

#32

Post by mushufasa » Sun, Feb 28, 2021, 5:56 PM UTC

birktj wrote: post #23

One of the things I find really cool about Ingenuity is how it is in large based on consumer hardware. The main processor is a Snapdragon 801 running Linux which communicates with Perseverance using the Zigbee protocol [1]. Perseverance on the other hand uses a RAD750 from 2001! If successful I hope this can lead to more modern hardware for these kinds of missions in general. [1] https://en.wikipedia.org/wiki/Ingenui…

One of the fascinating things about space silicon is that NASA spends many years hardening specific processors to withstand the types of shocks and electromagnetic interference from space travel. These intensive processes mean that the equipment they can use is always 10-20 years behind the modern equivalents.

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

#33

Post by fuzzy2 » Sun, Feb 28, 2021, 5:57 PM UTC

birktj wrote: post #23

One of the things I find really cool about Ingenuity is how it is in large based on consumer hardware. The main processor is a Snapdragon 801 running Linux which communicates with Perseverance using the Zigbee protocol [1]. Perseverance on the other hand uses a RAD750 from 2001! If successful I hope this can lead to more modern hardware for these kinds of missions in general. [1] https://en.wikipedia.org/wiki/Ingenui…

The CPU will probably be destroyed by radiation before long. I'd guess the key factors here were weight, power draw, size and perhaps performance. A radiation-hardened CPU probably didn't fit the bill. It's also super expensive.

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

#34

Post by NortySpock » Sun, Feb 28, 2021, 5:58 PM UTC

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…

Mars atmosphere is sometimes characterized as "enough so that you have to deal with it, but not enough to finish the job [with parachutes]"

I expect NASA just builds the biggest single parachute they think they can safely use, and then works downstream of that on a landing system.

Spirit and Opportunity used heatshield+parachute+rockets + bouncy airbags.

https://en.wikipedia.org/wiki/Mars_Exploration_Rover

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

#35

Post by l2p » Sun, Feb 28, 2021, 5:58 PM UTC

disago wrote: post #11

jefft255 wrote: post #2

I am incredibly excited for this. Can believe how nervous the control engineers must be for this. Not sure what quality of the footage to expect from this.

Sadly, this helicopter won't record any footage, it is only meant to test flight control and to proof that the idea will work for future missions. There is a interesting Veritasium episode (youtube) that talks about this (interviewing the actual designer from the JPL). The only footage will be from Perseverance filming the flight.

This is not correct, there are multiple downward facing cameras [a]:

1) Navigation (NAV) Camera. This is a global-shutter, nadir pointed grayscale 640 by 480 pixel sensor (Omnivision OV7251) mounted to a Sunny optics module. It has a field-of-view (FOV) of 133 deg (horizontal) by 100 deg (vertical) with an average Instantaneous Field-of-view (IFOV) of 3.6 mRad/pixel, and is capable of acquiring images at 10 frames/sec. Visual features are extracted from the images and tracked from frame to frame to provide a velocity estimate.

2) Return-to-Earth (RTE) Camera. This is a rolling shutter, high-resolution 4208 by 3120 pixel sensor (Sony IMX 214) with a Bayer color filter array mated with an O-film optics module. This camera has a FOV of 47 deg (horizontal) by 47 deg (vertical) with an average IFOV of 0.26 mRad/pixel.

[a]https://trs.jpl.nasa.gov/bitstream/handle/2014/46229/CL%2317...

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

#36

Post by Daniel_sk » Sun, Feb 28, 2021, 5:58 PM UTC

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 it does. The parachutes are unable to slow down the probes to a soft landing - they would have to be extremely large, which would make it even more heavy for landing. The large parachute on Perseverance slowed down the entry module to about 200 mph (321 km/h) which is not enough. Perseverance has a weight of 2,260 lbs (1,025 kilograms). The Mars Exploration Rover (Spirit) used parachute + retrorockets + inflatable airbags, but it weights only 408 lb (185 kilograms).

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

#37

Post by marcinzm » Sun, Feb 28, 2021, 5:58 PM UTC

birktj wrote: post #23

One of the things I find really cool about Ingenuity is how it is in large based on consumer hardware. The main processor is a Snapdragon 801 running Linux which communicates with Perseverance using the Zigbee protocol [1]. Perseverance on the other hand uses a RAD750 from 2001! If successful I hope this can lead to more modern hardware for these kinds of missions in general. [1] https://en.wikipedia.org/wiki/Ingenui…

As the name RAD750 indicates, that processor is designed to be radiation hardened which matters for longer missions. I doubt the Snapdragon 801 will survive as long or have as few errors but it also doesn't matter since Ingenuity isn't aimed for long term usage.

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

#38

Post by samfisher83 » Sun, Feb 28, 2021, 5:59 PM UTC

birktj wrote: post #23

One of the things I find really cool about Ingenuity is how it is in large based on consumer hardware. The main processor is a Snapdragon 801 running Linux which communicates with Perseverance using the Zigbee protocol [1]. Perseverance on the other hand uses a RAD750 from 2001! If successful I hope this can lead to more modern hardware for these kinds of missions in general. [1] https://en.wikipedia.org/wiki/Ingenui…

In general the older nodes work better for radiation and other cosmic forces.

https://en.m.wikipedia.org/wiki/Radiation_hardening

That's why they don't use the latest and greatest in the space.

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

#39

Post by darknavi » Sun, Feb 28, 2021, 5:59 PM UTC

birktj wrote: post #23

One of the things I find really cool about Ingenuity is how it is in large based on consumer hardware. The main processor is a Snapdragon 801 running Linux which communicates with Perseverance using the Zigbee protocol [1]. Perseverance on the other hand uses a RAD750 from 2001! If successful I hope this can lead to more modern hardware for these kinds of missions in general. [1] https://en.wikipedia.org/wiki/Ingenui…

> communicates with Perseverance using the Zigbee protocol

I hope they installed the Home Assistant Core docker container on Perseverance. Gotta get those sweet dashboards.

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

#40

Post by mrbonner » Sun, Feb 28, 2021, 6:00 PM UTC

Watching the PBS NOVA series “Finding life on Mars” I am so proud to see such an astounding diversity of ethnicities involved in the Mars 2020 projects. I can’t phantom any other countries would have inclusively included other ethnicities in such a high profile project. Despite so many set backs in 2020, the US is still the most inclusive country at least in science and research.