5 ms·

So many interesting details in this article. Snapdragon 801-based hw running Linux, sensor fusion from three sensors whereof some bought COTS from sparkfun (who

So many interesting details in this article. Snapdragon 801-based hw running Linux, sensor fusion from three sensors whereof some bought COTS from sparkfun (who make breakout boards for sensors, basically the sensor datasheet recommended design). 3 flights planned, but potentially more which will be planned after the three first. 30 day lifetime window, due to dependecy on the rover, which needs to conserve resources. I would looooove to know more more more about this. What did dev of this look like (eg simulators)? What's the flight envelope? What are the most important risks and how are they mitigated? What internal discussions took place (do this, prio that, don't do X etc). Just so much interesting stuff! Can't wait :) edit: from wikipedia: "Each flight is planned to be at altitudes ranging from 3–5 metres (10–16 ft) above the ground.[1] In up to 90 seconds per flight, it could travel as far as 50 metres (160 ft) downrange and then back to the starting area". "The helicopter uses counter-rotating coaxial rotors about 1.2 metres (4 ft) in diameter". Etc. Recommend the wiki page on it: https://en.wikipedia.org/wiki/Mars_Helicopter_Ingenuity https://en.wikipedia.org/wiki/Mars_Helicopter_Ingenuity

RapidFire 6y ago
This is the coolest part of the mission IMO. My big question is where does it land? Does it dock with the rover? It seems to power itself via a solar array. About 100 days into the mission they plan on launching the helicopter for the tiny lifespan window. I think the limit on its lifespan is really, "How long until destroyed by wind/dust". And then how long until it cannot charge its own batteries/sustain itself.
- foobarbecue 6y ago
  I agree, this is the coolest part, but the most useful part for humanity is MOXIE. It lands on the ground. And yes, dust on the panels is a big concern. (I work at JPL but not on Perseverance / Ingenuity)
  - RapidFire 6y ago
    That's really cool; thanks for your work!! I cant wait to see how Y'all figure out how to get those rock samples back to earth; that's gonnna be nuts XD
noselasd 6y ago
There's a bit of info here too : https://www.youtube.com/watch?v=mQu9m4MG5Gc https://www.youtube.com/watch?v=mQu9m4MG5Gc
manicdee 6y ago
Veritasium did an episode 'Mars Helicopter' containing some interesting discussions with the team that built it. https://www.youtube.com/watch?v=GhsZUZmJvaM https://www.youtube.com/watch?v=GhsZUZmJvaM nm it was already linked elsewhere
BelenusMordred 6y ago
I went down this rabbithole not long ago with the rovers on-board computer. The writeup from the people who designed the system was really approachable for someone without any aerospace experience. There's a lot of challenges and tradeoffs involved. Some takeaways: > Constrained CPU: 133MHz PowerPC, 128MB RAM, 4GB storage > Software written in C, OS is VxWorks > Only get contact a few times a day, rover must be charged and ready each time regardless of uncompleted tasks. Scheduling is hard. > Some tasks require parts preheated for X time, which depends on ambient temp, they use a lookup table for the time of day instead of measuring the temp directly. (Assume this is for reliability purposes) > High level activities are constructed in a GUI by the operations team, low-level tasks are written in XML, both are uploaded to the rover as a binary plan file. It's a good read, do recommend it. https://ai.jpl.nasa.gov/public/documents/papers/rabideau_iwpss2017_prototyping.pdf https://ai.jpl.nasa.gov/public/documents/papers/rabideau_iwp...
- milchek 6y ago
  > Some tasks require parts preheated for X time, which depends on ambient temp, they use a lookup table for the time of day instead of measuring the temp directly. (Assume this is for reliability purposes) That's an interesting one. Guessing that there also must not be that much variation of temp and weather conditions?
nuccy 6y ago
Actually the computing power of Ingenuity surpasses one of the Perseverance rover (and probably by a lot). The rover has a radiation hardened RAD 750 CPU (based on PowerPC 750 architecture, which was introduced in 1997 to compete with Intel's Pentium II [1,2]) with 250-150nm technology process operating at 200Mhz[3]. Ingenuity's Snapdragon 801 can reach up to 2.5 GHz and is based on more energy-efficient 28nm modern (released in 2014) ARM architecture [4]. This CPU even has Wi-Fi and GPS, though probably not much of a use on Mars :) 1. https://arstechnica.com/science/2019/11/space-grade-cpus-how-do-you-send-more-computing-power-into-space/ https://arstechnica.com/science/2019/11/space-grade-cpus-how... 2. https://en.wikipedia.org/wiki/RAD750 https://en.wikipedia.org/wiki/RAD750 3. https://mars.nasa.gov/mars2020/spacecraft/rover/brains/ https://mars.nasa.gov/mars2020/spacecraft/rover/brains/ 4. https://www.qualcomm.com/products/snapdragon-processors-801 https://www.qualcomm.com/products/snapdragon-processors-801
- donquichotte 6y ago
  Do you know why radiation hardening is not needed for the Ingenuity? Is there a mechanical shield? Or is it just the shorter runtime that makes the use of an off-the-shelf processor acceptable?
  - jhurliman 6y ago
    I had the opportunity to go down to JPL and speak with team members about this design decision. The space hardened processors are not fast enough to do real time sensor fusion and flight control, so they were forced to move to the faster snapdragon. This processor will have not flips on Mars, possibly up to every few minutes. Their solution is to hold two copies of memory and double check operations as much as possible, and if any difference is detected they simply reboot. Ingenuity will start to fall out of the sky, but it can go through a full reboot and come back online in a few hundred milliseconds to continue flying. In the far future where robots are exploring distant planets, our best tech troubleshooting tool is to turn it off and turn it on again.
    - alfla 6y ago

RapidFire 6y ago

This is the coolest part of the mission IMO. My big question is where does it land? Does it dock with the rover? It seems to power itself via a solar array. About 100 days into the mission they plan on launching the helicopter for the tiny lifespan window. I think the limit on its lifespan is really, "How long until destroyed by wind/dust". And then how long until it cannot charge its own batteries/sustain itself.

foobarbecue 6y ago
I agree, this is the coolest part, but the most useful part for humanity is MOXIE. It lands on the ground. And yes, dust on the panels is a big concern. (I work at JPL but not on Perseverance / Ingenuity)
- RapidFire 6y ago
  That's really cool; thanks for your work!! I cant wait to see how Y'all figure out how to get those rock samples back to earth; that's gonnna be nuts XD

noselasd 6y ago

There's a bit of info here too : https://www.youtube.com/watch?v=mQu9m4MG5Gc https://www.youtube.com/watch?v=mQu9m4MG5Gc

manicdee 6y ago

Veritasium did an episode 'Mars Helicopter' containing some interesting discussions with the team that built it. https://www.youtube.com/watch?v=GhsZUZmJvaM https://www.youtube.com/watch?v=GhsZUZmJvaM nm it was already linked elsewhere

BelenusMordred 6y ago

I went down this rabbithole not long ago with the rovers on-board computer. The writeup from the people who designed the system was really approachable for someone without any aerospace experience. There's a lot of challenges and tradeoffs involved. Some takeaways: > Constrained CPU: 133MHz PowerPC, 128MB RAM, 4GB storage > Software written in C, OS is VxWorks > Only get contact a few times a day, rover must be charged and ready each time regardless of uncompleted tasks. Scheduling is hard. > Some tasks require parts preheated for X time, which depends on ambient temp, they use a lookup table for the time of day instead of measuring the temp directly. (Assume this is for reliability purposes) > High level activities are constructed in a GUI by the operations team, low-level tasks are written in XML, both are uploaded to the rover as a binary plan file. It's a good read, do recommend it. https://ai.jpl.nasa.gov/public/documents/papers/rabideau_iwpss2017_prototyping.pdf https://ai.jpl.nasa.gov/public/documents/papers/rabideau_iwp...

milchek 6y ago
> Some tasks require parts preheated for X time, which depends on ambient temp, they use a lookup table for the time of day instead of measuring the temp directly. (Assume this is for reliability purposes) That's an interesting one. Guessing that there also must not be that much variation of temp and weather conditions?

nuccy 6y ago

Actually the computing power of Ingenuity surpasses one of the Perseverance rover (and probably by a lot). The rover has a radiation hardened RAD 750 CPU (based on PowerPC 750 architecture, which was introduced in 1997 to compete with Intel's Pentium II [1,2]) with 250-150nm technology process operating at 200Mhz[3]. Ingenuity's Snapdragon 801 can reach up to 2.5 GHz and is based on more energy-efficient 28nm modern (released in 2014) ARM architecture [4]. This CPU even has Wi-Fi and GPS, though probably not much of a use on Mars :) 1. https://arstechnica.com/science/2019/11/space-grade-cpus-how-do-you-send-more-computing-power-into-space/ https://arstechnica.com/science/2019/11/space-grade-cpus-how... 2. https://en.wikipedia.org/wiki/RAD750 https://en.wikipedia.org/wiki/RAD750 3. https://mars.nasa.gov/mars2020/spacecraft/rover/brains/ https://mars.nasa.gov/mars2020/spacecraft/rover/brains/ 4. https://www.qualcomm.com/products/snapdragon-processors-801 https://www.qualcomm.com/products/snapdragon-processors-801

donquichotte 6y ago
Do you know why radiation hardening is not needed for the Ingenuity? Is there a mechanical shield? Or is it just the shorter runtime that makes the use of an off-the-shelf processor acceptable?
- jhurliman 6y ago
  I had the opportunity to go down to JPL and speak with team members about this design decision. The space hardened processors are not fast enough to do real time sensor fusion and flight control, so they were forced to move to the faster snapdragon. This processor will have not flips on Mars, possibly up to every few minutes. Their solution is to hold two copies of memory and double check operations as much as possible, and if any difference is detected they simply reboot. Ingenuity will start to fall out of the sky, but it can go through a full reboot and come back online in a few hundred milliseconds to continue flying. In the far future where robots are exploring distant planets, our best tech troubleshooting tool is to turn it off and turn it on again.
  - alfla 6y ago