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Meet The Nuclear-Powered Self-Driving Drone NASA Is Sending To A MoonOf Saturn



 
 
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  #1  
Old September 17th 19, 06:33 PM posted to sci.space.policy
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Default Meet The Nuclear-Powered Self-Driving Drone NASA Is Sending To A MoonOf Saturn

"On the face of it, NASA's newest probe sounds incredible. Known as Dragonfly, it
is a dual-rotor quadcopter (technically an octocopter, even more technically an X8
octocopter); it's roughly the size of a compact car; it's completely autonomous;
it's nuclear powered; and it will hover above the surface of Saturn's moon Titan.

But Elizabeth Turtle, the mission's principle investigator at the Johns Hopkins
Applied Physics Laboratory, insists that this is actually a pretty tame space
probe, as these things go.

"There's not a lot of new technology," she says.

Quadcopters (even X8 octocopters) are for sale on Amazon these days. Self-driving
technology is coming along quickly. Nuclear power is harder to come by, but the
team plans to use the same kind of system that runs NASA's Curiosity rover on
Mars. Everything that's going into Dragonfly is already being used somewhere else.

Which is not to say that the idea of a nuclear-powered drone flying around a moon
of Saturn doesn't sound kind of crazy."

See:

https://www.npr.org/2019/09/17/76064...moon-of-saturn

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  #2  
Old September 18th 19, 05:46 AM posted to sci.space.policy
William Elliot[_4_]
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Default Meet The Nuclear-Powered Self-Driving Drone NASA Is Sending ToA Moon Of Saturn

Which moon? Titan?

Which is not to say that the idea of a nuclear-powered drone flying around a moon
of Saturn doesn't sound kind of crazy."


Then after it's life, it crash lands on the moon?
So if there's life there, the next time we look, it will be different?


"On the face of it, NASA's newest probe sounds incredible. Known as Dragonfly, it
is a dual-rotor quadcopter (technically an octocopter, even more technically an X8
octocopter); it's roughly the size of a compact car; it's completely autonomous;
it's nuclear powered; and it will hover above the surface of Saturn's moon Titan.

But Elizabeth Turtle, the mission's principle investigator at the Johns Hopkins
Applied Physics Laboratory, insists that this is actually a pretty tame space
probe, as these things go.

"There's not a lot of new technology," she says.

Quadcopters (even X8 octocopters) are for sale on Amazon these days. Self-driving
technology is coming along quickly. Nuclear power is harder to come by, but the
team plans to use the same kind of system that runs NASA's Curiosity rover on
Mars. Everything that's going into Dragonfly is already being used somewhere else.

See:

https://www.npr.org/2019/09/17/76064...moon-of-saturn


  #3  
Old September 18th 19, 02:19 PM posted to sci.space.policy
Scott Kozel
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Posts: 28
Default Meet The Nuclear-Powered Self-Driving Drone NASA Is Sending To AMoon Of Saturn

On Tuesday, September 17, 2019 at 1:33:22 PM UTC-4, wrote:
"On the face of it, NASA's newest probe sounds incredible. Known as Dragonfly, it
is a dual-rotor quadcopter (technically an octocopter, even more technically an X8
octocopter); it's roughly the size of a compact car; it's completely autonomous;
it's nuclear powered; and it will hover above the surface of Saturn's moon Titan.

But Elizabeth Turtle, the mission's principle investigator at the Johns Hopkins
Applied Physics Laboratory, insists that this is actually a pretty tame space
probe, as these things go.

"There's not a lot of new technology," she says.

Quadcopters (even X8 octocopters) are for sale on Amazon these days. Self-driving
technology is coming along quickly. Nuclear power is harder to come by, but the
team plans to use the same kind of system that runs NASA's Curiosity rover on
Mars. Everything that's going into Dragonfly is already being used somewhere else.

Which is not to say that the idea of a nuclear-powered drone flying around a moon
of Saturn doesn't sound kind of crazy."

See:

https://www.npr.org/2019/09/17/76064...moon-of-saturn


I saw an article that said that the atmospheric density at the surface is
2 times that of Earth, the gravity is 1/3 that of Earth, and that a
human could devise wings and be able to fly like a bird.
  #4  
Old September 18th 19, 03:48 PM posted to sci.space.policy
David Spain
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Default Meet The Nuclear-Powered Self-Driving Drone NASA Is Sending To AMoon Of Saturn

On 2019-09-17 1:33 PM, wrote:
Which is not to say that the idea of a nuclear-powered drone flying around a moon
of Saturn doesn't sound kind of crazy."

See:

https://www.npr.org/2019/09/17/76064...moon-of-saturn


This is pretty tame nuclear technology. A low power RTG. A quick
websearch (DuckDuckGo don't be evil) to Wikipedia yields three links:

https://en.wikipedia.org/wiki/Dragonfly_(spacecraft)
http://www.lpl.arizona.edu/~rlorenz/jbis.pdf
https://dragonfly.jhuapl.edu/News-an..._03-Lorenz.pdf

From the third link see section titled Power 2.1 (pgs 223-224). The two
main points:

1) Titan is Very Cold (you will need ample energy to heat the probe)
2) Titan is Very Dark (no solar cells)

What is interesting is the analysis of why not just bring O2 to combust
with the abundant methane already in Titan's atmosphere? The problem is
the ambient temperature. Combustion products emitted by an APU like
combuster would freeze quickly and could potentially block an exhaust
port. Monoprop hydrazine has a similar issue. Also the fact that you
need two molecules of oxygen to burn one of methane and thus only 50%
better than bringing both fuel and oxidizer from Earth. Thus a big
oxygen tank is needed, brought all the way from Earth.

The second link to the most recent paper proposes an Multi-Mission
Radioisotope Thermal Electric Generator to recharge an on-board battery
pack with efficiencies similar to the batteries used in a Tesla. Thus I
presume we are talking some type of Lithium-Ion. I'm assuming they are
using a hybrid RTG/Li-Ion battery power system in order to supply the
higher electric energy demand needed to power the quad-copter motors. I
believe this is the weakest link in the proposed design because the
batteries do add a lot of mass to the probe. Both the 2018 and 1999
papers leave the exact RTG technology to be used also somewhat
undefined. IMO I think they need to nail the energy budget first to come
up with the requirements needed of a workable power unit and stop
writing about up-and-coming power technology. Go with what you can have
in hand now or don't commit to a launch date.

I assume the crash scenario would only be for an unintended loss of
control, not because you fly it when power is no longer nominal for
flight. I suspect the RTGs are heavy duty enough likely to survive a
fall in Titan's very low gravity. I doubt the shielding of the device
would even be breached. So effectively, what would happen to any
potential life on Titan should the probe crash? Nothing.

The link to the third paper is quite old (1999). For the purposes of
discussion I challenge other readers to due some research and update the
information I have provided to something more recent. (Gosh! You mean to
actually do some RESEARCH before commenting here?).

Dave
  #5  
Old September 18th 19, 03:50 PM posted to sci.space.policy
David Spain
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Posts: 2,593
Default Meet The Nuclear-Powered Self-Driving Drone NASA Is Sending To AMoon Of Saturn

References to papers and links got scrambled.

The second link is the older paper 1999.
The third link is the most recent paper 2018.

I thought I had fixed those!

Dave

  #6  
Old September 18th 19, 04:24 PM posted to sci.space.policy
David Spain
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Posts: 2,593
Default Meet The Nuclear-Powered Self-Driving Drone NASA Is Sending To AMoon Of Saturn

On 2019-09-18 9:19 AM, Scott Kozel wrote:
I saw an article that said that the atmospheric density at the surface is
2 times that of Earth, the gravity is 1/3 that of Earth, and that a
human could devise wings and be able to fly like a bird.


The project team's most recent paper says atmospheric density is 4x
Earth at Sea Level, viscosity is 3x smaller than Earth (be careful of
propeller speed) and gravity is 1/7 of Earth's.

"Daytime" surface illumination is 1000x less than Earth or 1000x full
moonlight predominately in red and near IR light, thus a human explorer
would get a largely dim B&W experience w/o a headlight.

See Table 1:

https://dragonfly.jhuapl.edu/News-an..._03-Lorenz.pdf

Dave
  #7  
Old September 19th 19, 04:40 AM posted to sci.space.policy
Scott Kozel
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Posts: 28
Default Meet The Nuclear-Powered Self-Driving Drone NASA Is Sending To AMoon Of Saturn

On Wednesday, September 18, 2019 at 11:24:55 AM UTC-4, David Spain wrote:
On 2019-09-18 9:19 AM, Scott Kozel wrote:

I saw an article that said that the atmospheric density at the surface is
2 times that of Earth, the gravity is 1/3 that of Earth, and that a
human could devise wings and be able to fly like a bird.


The project team's most recent paper says atmospheric density is 4x
Earth at Sea Level, viscosity is 3x smaller than Earth (be careful of
propeller speed) and gravity is 1/7 of Earth's.


Getting down toward the temperature of LOX, so a human would have a hard
time surviving there!

"Daytime" surface illumination is 1000x less than Earth or 1000x full
moonlight predominately in red and near IR light, thus a human explorer
would get a largely dim B&W experience w/o a headlight.


The surface photos from Huygens seemed brighter and more colorful than that.
  #8  
Old September 20th 19, 01:10 PM posted to sci.space.policy
David Spain
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Posts: 2,593
Default Meet The Nuclear-Powered Self-Driving Drone NASA Is Sending To AMoon Of Saturn

On 2019-09-18 11:40 PM, Scott Kozel wrote:
On Wednesday, September 18, 2019 at 11:24:55 AM UTC-4, David Spain wrote:
"Daytime" surface illumination is 1000x less than Earth or 1000x full
moonlight predominately in red and near IR light, thus a human explorer
would get a largely dim B&W experience w/o a headlight.


The surface photos from Huygens seemed brighter and more colorful than that.


I suspect those photos were post processed a bit to bring out contrast.
In full moonlight is IS barely possible to make out color. So it might
be possible that 1000x moonlight would show some color but with the
visible spectrum largely in the color red, I suspect your eye's rods
rather than cones would be doing most of the heavy lifting and colors
will look false (like green as grey and yellow maybe as white, etc)
until your headlight hits them.

Most definitely one's suit will need ample heating. Maybe it too
contains a portable atomic reactor!

Dave

  #9  
Old September 20th 19, 01:15 PM posted to sci.space.policy
David Spain
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Posts: 2,593
Default Meet The Nuclear-Powered Self-Driving Drone NASA Is Sending To AMoon Of Saturn

On 2019-09-17 1:33 PM, wrote:
"On the face of it, NASA's newest probe sounds incredible. Known as Dragonfly, it [...]

See:

https://www.npr.org/2019/09/17/76064...moon-of-saturn

I never thank for these posts!
Keep them coming thank you!

Dave
 




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