NASA Releases Details of Titan Submarine Concept

Zothecula writes: Now that NASA has got the hang of planetary rovers, the space agency is looking at sending submarines into space around the year 2040. At the recent 2015 NASA Institute for Advanced Concepts Symposium, NASA scientists and engineers presented a study of the Titan Submarine Phase I Conceptual Design (PDF), which outlines a possible mission to Saturn's largest moon, Titan, where the unmanned submersible would explore the seas of liquid hydrocarbons at the Titanian poles.

"At its heart, the submarine would use a 1 kW radiothermal Stirling generator. This would not only provide power to propel the craft, but it would also keep the electronics from freezing. Unfortunately, Titan is so cold that it's almost a cryogenic environment, so the waste heat from the generator would cause the liquids around it to boil and this would need be taken into account when designing the sub to minimize interference. However, NASA estimates that the boat could do about one meter per second (3.6 km/h, 2.2 mph)."

Comments

Re:Drop it on Europa

[Rei]

What you're describing is an incredibly challenging tasks. One needs several missions to get to better know Europa in general, and specific potential entry areas in particular, first. These missions are going to be expensive and have long lead times. And an actual boring / submersible mission is going to be extremely expensive.

Titan has one main strike against its exploration, that it's so dang far away. But almost everything else about it is tailor-made for exploration. It's ideal for aerocapture. It's trivial to stay aloft, at an altitude of your choice, be it by hot air or lifting gas balloon, blimp (likewise), helicopter, fixed-wing aircraft, tilt-wing aircraft, etc. Low temperatures pose some difficulties but can be nice for electronics, and the rate of heat loss (even in a hot air balloon concept) is so low at such low temperatures that you don't need very big heat sources. The hydrocarbon seas are permanently exposed for whatever means of exploration (aerial, boat, submarine) you choose. Ascent requirements (sample return, for example) are surprisingly low versus a body of that size due to the ability to fly so high in the significant pressure / low gravity environment before needing to fire rockets. And so forth. And there's so darn much we don't know about Titan, perhaps even more than Europa. There's constant complex organic chemistry going on in the upper atmosphere of which we know almost nothing, and probably even some on the surface. There's probable liquid water under the surface and cryovolcanoes that erupt it to the surface. There's earthlike weathering processes done with/to completely different materials, and the entire gas cycle is a giant mystery right now. So yes, I'm pretty excited about whatever mission goes to Titan next.

Too bad the next launch window to Saturn (2018, 4,13km/s delta-V, 8,2 years) is simply not going to happen. : There's not going to be such a low delta-V/time window for a long time - 2020 is 5,18 km/s / 11,0y; 2021 is 4,80km/s / 8,8y; 2024 is 4,81km/s / 10,4y; etc. So if we're lucky maybe we could get the 2021 window (though the increased delta-V reqs would significantly hurt the payload)... otherwise, there won't be a spacecraft getting to Saturn before the mid 2030s. :

Re:25 Years from now?

[Rei]

You joke, but the ability to reconfigure spacecraft on the fly even on the smaller scale has proven itself valuable time and time again. I love how they came up with a trick after New Horizons was launched to nearly double its communication rate. It has two radio transmitters, one primary and one backup, and one dish. When they launched, it seemed obvious that only one could be used at a time - but en route someone figured out that if you have one transmit with right-handed polarization and the other with left-handed, they can both transmit at the same time, and then on Earth the two signals can be separated out. But since the spacecraft wasn't designed for enough power to use them at once (that was never supposed to be necessary), they needed to find a trick to get more power. And it's not easy, given that there's not a lot of things running when the probe is just drifting in deep space - what are you going to do, shut down your guidance computer? Well... yes, that's exactly what they came up with - when they've filled up their memory, they align the antenna, then spin up the spacecraft, shut down the guidance computer, transmit at double speed until the memory is free, then restart guidance and stop the spin so that they can resume data collection.

While 3d printing and robotic arms for assembly is a stretch at present, the importance of having hardware flexibility is increasingly being demonstrated in space missions.