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Part of NASA's Mars 2020 mission, Ingenuity is planned for deployment in April 2021, about 60 days after landing with the rover Perseverance in the crater Jezero at Octavia E. Butler Landing on 18 February 2021.

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Why didn't Ingenuity (helicopter) deploy immediately right after rover landing?

Vikki
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Murray Ignatius
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Why didn't Ingenuity (helicopter) deploy immediately right after rover landing?

For many reasons. Number one is that helicopter is an experimental (i.e., not mission-critical) item. Mission-critical aspects took a much higher priority.

Another reason is that Ingenuity deployment requires the Perseverance to move to a flat spot, drop the helicopter from its undercarriage, and then back away. Perseverance happened to land on a good spot for deployment, but that is a bit irrelevant as Perseverance didn't have the capability to back away right after rover landing.

That gets to the final reason, which is there's only so much room on Perseverance's limited data storage for programs. The main flight computer was used to guide the descent vehicle and the skycrane through the entry, descent, and landing process. The software that enables the rover to rove was not installed on the vehicle at the time of landing. JPL long ago developed the ability to upload new software to their remote vehicles. This takes time, lots of time.

Think of how much time it took you to download a program twenty years ago. Now multiply that by a large number. The overall upload takes place in pieces, and each upload has to be confirmed before it is put into place, with a twenty minute round-trip time. The overall process takes weeks to complete.

David Hammen
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    Interesting! Now I'm wondering how much memory the copter has for programs and how much computing power it has for navigation, guidance, and control. I imagine not much? Or is Perseverance doing the calculations for the copter and transmitting them wirelessly for the copter to follow? Would this even make sense to do? –  Mar 22 '21 at 01:34
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    @user39728 Ingenuity is a technology demonstration experiment. It is not mission critical and as such it is not expected to do much except to fly. It will be a complete failure if it doesn't even take off. It will be deemed a marginal success if it takes off but crashes shortly later (but it will be written off for future missions). It will be deemed a complete success if it just once takes off and lands without crashing. The hope is that it will take off and land five times. Even if it succeeds just once, let alone five times, future Mars missions most likely will more capable helicopters. – David Hammen Mar 22 '21 at 02:13
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    @user39728 there's a nice discussion of the whole system in the paper that I've linked to in Can anything at Mars speak 900 MHz ZigBee besides Ingenuity helicopter and Perseverance rover? – uhoh Mar 22 '21 at 02:18
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    Why is storage at such a premium in this instance ? Storage medium is the smallest and largest capacity its ever been. With you being able to get 100's of terabytes in a space not much larger than Phone. – GamerGypps Mar 22 '21 at 11:44
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    @GamerGypps Because Perserverance is implemented with 2016-2017 tech: https://space.stackexchange.com/questions/50498/why-did-curiosity-not-have-a-camera-on-board-to-record-the-landing, and radiation hardening involves a significant density penalty. – user1937198 Mar 22 '21 at 12:14
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    @user1937198 Not 2016-2017 tech. It's implemented with slowed-down 1998 tech. The flight computer is the same design as a 1998 Power Mac, but with the CPU clock running at about half the speed as a 1998 Power Mac. – David Hammen Mar 22 '21 at 12:31
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    @GamerGypps Those 100 TB drives one can now buy wouldn't last very long in space. Perseverance's flight computer has 2 gigabytes of flash memory, 256 megabytes of DRAM, and 256 megabytes of EPROM. – David Hammen Mar 22 '21 at 12:47
  • @DavidHammen Why is it so far behind in tech ? Whats stopping them from radiation hardening a newer better processor than from a PowerPC 750 ? I understand these plans were in motions years ago but not that far. – GamerGypps Mar 22 '21 at 14:21
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    @GamerGypps, using a smaller process node means more vulnerability to radiation. So some of the same advances that make newer tech faster (high-capacity, high-density, etc) also make it more vulnerable. – Charles Duffy Mar 22 '21 at 14:23
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    Note the non-critical parts of the mission do use newer technology: ingenuity uses a Snapdragon 801 (smartphone processor from 2014) and the EDL camera system used a commercial Intel Atom processor and 480 GB SSD. – 2012rcampion Mar 22 '21 at 15:21
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    @GamerGypps When I started working in this field, spacecraft state of the art was five years behind, maybe ten years behind, earthbound state of the practice. Part of the problem is that because avionics design impacts so many other systems, avionics design decisions are made early on in the spacecraft design process. That alone accounts for perhaps five years. But now we're twenty years behind, and that's primarily because earthbound computing doesn't have to worry much about the severe radiation effects that plague computers that operate outside of the Van Allen Belts. – David Hammen Mar 22 '21 at 16:17
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    @GamerGypps manufacturing a spacecraft takes years, and with years of designing before that. You can't change the hardware easily after it's been designed. See Why are spacecraft computers obsolete at launch? – phuclv Mar 23 '21 at 08:55
  • I see,Thanks for the information guys! I appreciate it. – GamerGypps Mar 23 '21 at 09:07
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    I'm hoping the microphones on Perseverance will pick up sounds of the various bolt breaking devices and pyro cable cutters being activated to release and align Ingenuity for dropping to the surface – giles tester Mar 25 '21 at 05:37