NASA plans to launch a spacecraft to Titan • Hacker News Board

Re: NASA plans to launch a spacecraft to Titan

#71

Post by gene-h » Fri, Jun 28, 2019, 7:35 PM UTC

nsxwolf wrote: post #58

rzimmerman wrote: post #4

A flying drone is a really solid idea for a Titan lander for a couple reasons: * The surface atmosphere density is higher than Earth's (1.5 atm) * Gravitational force is much lower (0.15g) * We don't know a lot about the surface composition or topography, so wheels and motors represent a challenge * Visibility may be poor, making visual navigation tricky (though that's also a problem for a flying vehicle I suppose) I…

What about hydrogen fuel cells? Isn't the whole place basically nothing but fuel?

it's all fuel, but there's no oxidizer

Re: NASA plans to launch a spacecraft to Titan

#72

Post by Sharlin » Fri, Jun 28, 2019, 7:35 PM UTC

LordLotherak wrote: post #46

NASA is really good at planning future missions. Implementing them? I've heard hundreds of fantastical half-baked ideas and very few of them materialize over the course of my 46 years on earth.

Eh, almost every NASA robotic mission that has gotten this far in the design and selection process has also flown. They're way past the "fantastical half-baked idea" stage. The financial reality is that NASA can only finance one or two billion-dollar missions per decade, and the competition is rather fierce. To be selected as the New Frontiers class mission of the late 2020s is a big deal, and you can be sure that at this point the proposing team has made a very solid case for their mission.

Re: NASA plans to launch a spacecraft to Titan

#73

Post by jvanderbot » Fri, Jun 28, 2019, 7:36 PM UTC

Robotbeat wrote: post #60

maxxxxx wrote: post #8

I love this mission. From a science point of view it’s probably good to send similar and well tested rovers to Mars. But to me it gets boring. I think NASA used to get a lot of fascination from doing the seemingly impossible like flying to the moon. So I think a mission like this will be fascinating for a lot of people. Also it may spawn off a lot of technology. I hope for a submarine mission to Europa.

I think a flying mission is actually superior to a rover as it can cover far more ground and reach some sites that wouldn't be feasible for a rover. And Titan is uniquely suited to using flight to explore as its gravity is a factor 7.25 lower and its atmosphere a factor of 4.4x denser. That means it's about 30 times easier to hover and covering the same distance is at least 7 times as efficient as on Earth, besides h…

This is why theres a helicopter going to Mars.

Re: NASA plans to launch a spacecraft to Titan

#74

Post by calcifer » Fri, Jun 28, 2019, 7:39 PM UTC

plutonorm wrote: post #67

What. How are they going to detect life on titan? They can't even detect life on mars. I mean to say, even when we know the kind of life we are looking for we get confused about how to confirm or deny its existence. So they want to design a small flying drone that works in extremely hostile conditions, that also has the kinds of sophisticated instruments needed to look for life? And not just life, life of potentially…

> Finish up the Viking labelled release experiments on mars first, then go take a look in the mid Venusian atmosphere. Then take a gander at europa

This is exactly why I like HN. Here, you have the true experts contributing valuable science with their credentials laid bare, as opposed to the pencil pushers at NASA who probably only approved this mission because it sounded cool.

Re: NASA plans to launch a spacecraft to Titan

#75

Post by gattr » Fri, Jun 28, 2019, 7:40 PM UTC

Associated read: "Titan" by Stephen Baxter. Hard SF describing a manned mission to Titan using present-day level tech; great attention to detail, but be warned that the overall tone is rather depressing.

Myself, I'm absolutely fascinated by the confirmed hydrocarbon lakes and rivers on Titan and can't wait to see actual optical images from up close (so far we only got synthetic-aperture radar images [0]).

[0] https://en.wikipedia.org/wiki/Titan_(moon)#Lakes

Re: NASA plans to launch a spacecraft to Titan

#76

Post by Robotbeat » Fri, Jun 28, 2019, 7:40 PM UTC

jvanderbot wrote: post #73

Robotbeat wrote: post #60

Earlier quoted context omitted.

I think a flying mission is actually superior to a rover as it can cover far more ground and reach some sites that wouldn't be feasible for a rover. And Titan is uniquely suited to using flight to explore as its gravity is a factor 7.25 lower and its atmosphere a factor of 4.4x denser. That means it's about 30 times easier to hover and covering the same distance is at least 7 times as efficient as on Earth, besides h…

This is why theres a helicopter going to Mars.

Indeed... although on Mars it's about 15 times harder to hover than Earth due to the 50x lower atmospheric density.

Re: NASA plans to launch a spacecraft to Titan

#77

Post by cookingrobot » Fri, Jun 28, 2019, 7:42 PM UTC

AnIdiotOnTheNet wrote: post #57

ajmurmann wrote: post #52

Earlier quoted context omitted.

Hah, I was always intrigued by the idea of placing solar cells on the bright side of Mercury and servers on the dark side. I wonder what other good options might exist in the solar system.

Mercury's whisper thin atmosphere won't be much use for cooling anything, though possibly the surface would be. However, the real problem is that Mercury isn't actually tidally locked anyway.

In certain regions on Mercury the temperature stays within 1 degree of room temperature less than a meter underground. http://einstein-schrodinger.com/Mercury_temperature.pdf It’s actually relatively habitable. http://einstein-schrodinger.com/mercury_colony.html

Re: NASA plans to launch a spacecraft to Titan

#78

Post by jvanderbot » Fri, Jun 28, 2019, 7:42 PM UTC

rolltiide wrote: post #6

It is nice that multiple public sector agencies worldwide are doing space travel now, with the private sector close behind. Relying solely on NASA and the political funding machinations of the White House and Congress would put our understanding of the planets very far behind.

I'm confused by your comment. this is absolutely a NASA mission, subject to all the whims of congress that any other is.

APL has long bid on missions and instrument proposals just like other institutions.

Re: NASA plans to launch a spacecraft to Titan

#79

Post by gene-h » Fri, Jun 28, 2019, 7:43 PM UTC

cwkoss wrote: post #17

rzimmerman wrote: post #4

A flying drone is a really solid idea for a Titan lander for a couple reasons: * The surface atmosphere density is higher than Earth's (1.5 atm) * Gravitational force is much lower (0.15g) * We don't know a lot about the surface composition or topography, so wheels and motors represent a challenge * Visibility may be poor, making visual navigation tricky (though that's also a problem for a flying vehicle I suppose) I…

In addition to lack of solar energy, I wonder if nuclear power source is necessary to keep batteries or other electronics warm enough to function properly. Conversely, on Titan, we won't need to worry about heat sinks as everything is kept at ~94K in a bath of liquid and frozen methane. Perhaps in a few hundred years AWS's most popular region for intensive compute will be under Titan's methane sea. High spin up cost,…

Interestingly they actually exploit these cold temperatures to keep things cool. The Dragonfly Gamma-Ray and Neutron Spectrometer(DraGNS)'s gamma ray detector is mounted outside.[0] In most other probes the detector would need to kept cold with a cryocooler. [0]https://www.jhuapl.edu/techdigest/TD/td3403/34_03-Lorenz.pdf

Re: NASA plans to launch a spacecraft to Titan

#80

Post by MereInterest » Fri, Jun 28, 2019, 7:44 PM UTC

AnIdiotOnTheNet wrote: post #57

ajmurmann wrote: post #52

Earlier quoted context omitted.

Hah, I was always intrigued by the idea of placing solar cells on the bright side of Mercury and servers on the dark side. I wonder what other good options might exist in the solar system.

Mercury's whisper thin atmosphere won't be much use for cooling anything, though possibly the surface would be. However, the real problem is that Mercury isn't actually tidally locked anyway.

You could have the facility move constantly to keep the facility straddled across the sunlight line. At the equator, this would require constantly moving at about 7 mph, though you could reduce the speed necessary by moving to higher latitudes.