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‘Dragonfly’ Chosen to Explore Titan

We’ve looked at a number of concepts for exploring Titan over the years, from aircraft capable of staying aloft for a year or more to balloons and boats that would float on the moon’s seas. Dragonfly, the work of a team based at Johns Hopkins University’s Applied Physics Laboratory in Laurel, MD, is a rotorcraft with the capability of exploiting Titan’s thick atmosphere to stop, sample, and move on, shaping its investigations along the way as it explores an environment rich in targets.

These are the advantages of a rover, though here we’re in a landscape so exotic that it enables different tools than the ones we use on Mars. And with the success of the Martian rovers in mind, what good news that NASA has chosen Dragonfly as the next mission in its New Frontiers program. We can anticipate launch in 2026 and arrival at Titan in 2034, with a craft that will sample surface organics and examine prebiotic chemistry and potential habitability.

Image: This illustration shows NASA’s Dragonfly rotorcraft-lander approaching a site on Saturn’s exotic moon, Titan. Taking advantage of Titan’s dense atmosphere and low gravity, Dragonfly will explore dozens of locations across the icy world, sampling and measuring the compositions of Titan’s organic surface materials to characterize the habitability of Titan’s environment and investigate the progression of prebiotic chemistry. Credit: NASA/JHU APL.

APL’s Elizabeth ‘Zibi’ Tuttle is chief investigator for Dragonfly:

“Titan is such an amazing, complex destination. We don’t know the steps that were taken on Earth to get from chemistry to biology, but we do know that a lot of that prebiotic chemistry is actually happening on Titan today. We are beyond excited for the chance to explore and see what awaits us on this exotic world.”

No more so than all of us who lamented the end of Cassini’s mission and wondered whether the dynamic concepts for Titan exploration being offered would ever see the light of day. But think about how much Cassini itself played into Dragonfly. We have 13 years of data from the Saturn orbiter, which makes target selection a matter of choosing among abundance. The plan is for Dragonfly to land on the moon’s equator, in the dune fields now known as Shangri-La.

Dragonfly can then move on in flights of about 8 kilometers each, sampling the wide-range of Titan’s geography, while heading for an impact crater called Selk, which appears to be rich in complex molecules — carbon united with hydrogen, oxygen and nitrogen. Along the way, the mission takes advantage of Titan’s calm, dense atmosphere (four times denser than Earth’s), along with its low gravity, to travel widely. The plan is for a journey of more than 175 kilometers, twice the distance of all the Mars rovers thus far deployed.

Dragonfly itself has eight rotors, giving it the aspect of a large drone. APL talks about one hop per full Titan day, each of these being 16 Earth days, within the context of a two-year mission. Although Dragonfly in flight is a dazzling prospect, the craft will spend most of its time on the surface conducting science measurements with the help of power from a Multi-Mission Radioisotope Thermoelectric Generator (MMRTG), with recharging occurring at night.

In flight, Dragonfly will provide images of surface geology (imagine the views we are going to see, although bear in mind that during flight, the high gain antenna will be stowed — no live streaming), while scouting for ground sites to study and building up a profile of Titan’s atmosphere. On the surface, the craft will use a mass spectrometer to examine the moon’s chemistry and the production of biologically interesting compounds. A neutron-activated gamma-ray spectrometer will offer readings on surface composition, while meteorology sensors will track atmospheric variation as imaging and seismic sensors probe geologic features.

Image: This artist’s concept shows a possible model of Titan’s internal structure that incorporates data from NASA’s Cassini spacecraft. In this model, Titan is fully differentiated, which means the denser core of the moon has separated from its outer parts. This model proposes a core consisting entirely of water-bearing rocks and a subsurface ocean of liquid water. The mantle, in this image, is made of icy layers, one that is a layer of high-pressure ice closer to the core and an outer ice shell on top of the sub-surface ocean. A model of Cassini is shown making a targeted flyby over Titan’s cloudtops, with Saturn and Enceladus appearing at upper right. The model, developed by Dominic Fortes of University College London, England, incorporates data from Cassini’s radio science experiment. Credit: A. D. Fortes/UCL/STFC.

And so we begin preparations for exploring a place of liquid methane seas and the potential for liquid water beneath a surface where water ice stands in for bedrock. We’ll be studying up close an atmosphere composed primarily of nitrogen with about 5 percent methane which, when exposed to sunlight, forms complex organic compounds. All this within a hydrological cycle of methane clouds and flowing liquid methane that fills lakes and seas. Congratulations to Elizabeth ‘Zibi’ Tuttle and the entire team. What prospects await…

Addendum: Paul Voosen’s article on Dragonfly on the Science site adds some details about the equipment aboard:

Dragonfly won’t be equipped with a robotic arm, like the recent Mars rovers. Its exploration will first be guided by an instrument on its belly that will bombard the ground with neutron radiation, using the gamma rays this attack releases to differentiate between basic terrain types, such as ammonia-rich ice or carbon-rich sand dunes. Its two landing skids will also each carry a rotary-percussive drill capable of taking samples and feeding them through a pneumatic tube to a mass spectrometer that can analyze their composition. The sampling system represented a risk for the mission; NASA scientists were concerned Titan’s hydrocarbon-rich atmosphere could clog it, Zurbuchen says. “It’s the oil spill version of an atmosphere.” Over the past 2 years, after extensive testing with “pathological” materials and a redesign, Turtle says, the agency’s fears were allayed.

Voosen also points out that the Dragonfly seismometer could use vibrations induced by Titan’s tidal lock with Saturn to give us some indication of the size of the ocean beneath the crust. Ultimately, the nuclear power source could last for 8 years, meaning extended missions are in the cards.

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{ 53 comments… add one }
  • John walker June 28, 2019, 9:11

    Triboelectrically charged hydrocarbon sands may foul both the rotors and sample intake.

    https://www.researchgate.net/publication/315959489_Electrification_of_sand_on_Titan_and_its_influence_on_sediment_transport

    An article in Nature Geoscience from March 2017 suggested that the organic sands on Titan may be highly charged and prone to clumping. If true, additional disturbances via kinetic mechanisms like the downdraft of Dragonfly’s rotors and the suction of it’s sample intake will lead to adhesion to the spacecraft with resultant increased friction at the rotors, obstruction of camera lens and contamination of the sample intake mechanism.

    Paul, take a look at the article. It certainly seems plausible. If you agree, please reach out to the project team. I would very much like to know how they plan to mitigate the risks should the worst case come to pass. Because the very nature of Dragonfly’s designs are from my perspective perfect for the creation of statically charged fouling.

    • Paul Gilster June 28, 2019, 9:57

      Let me see if I can get a comment from APL.

      • Paul Gilster June 28, 2019, 11:41

        From Ralph Lorenz, a project scientist on Dragonfly:

        “We are well aware of this issue – in fact as well as writing two books about Titan, I did the lightning hazard assessment for Huygens, and I’ve written a text on sand dunes, and edited one on dust devils (a topic on which I do Mars-related fieldwork). I am familiar with the Mendez-Harper paper and in fact myself had noted in a paper of my own that triboelectric charging effects may be important in influencing the mechanics of sand on Titan.

        “Dragonfly will have an electrically-grounded surface (including a conductive film on the camera windows which our tests show is very effective at mitigating adhesion of Titan organics), and is equipped with static discharge wicks (like those on aircraft, and Huygens) to prevent charge buildup on the vehicle overall.

        “On the flip side, these phenomena are quite interesting, and Dragonfly also has a sensor to measure the electric field, which we expect will fluctuate when we deliberately stimulate the sand to move with the rotor downwash in an experiment to determine how much wind is needed to build the sand dunes.”

        • John walker June 28, 2019, 12:02

          Excellent. Thanks.

  • Caravela Sideral June 28, 2019, 10:24

    Fantastic prospects, indeed. I just hope we can live long enough to enjoy the images and discoveries of Dragonfly.

  • Hal_S June 28, 2019, 11:01

    So, what are the OTHER options for flying around Titan?

    I recall that in addition to the “Dragonfly”, there was a direct-heat atmospheric montgolfière “hot air” balloon concept.

    I’m curious, has there been any thought of leveraging the RTG heat and say, a platinum catalyst, to put waste heat into endothermic reactions with atmospheric gasses, e.g. dumping waste heat into a catalyst to chemically generate hydrogen?
    Because that would be quite useful. Dumping heat by heating gasses is convection limited. Dumping heat by driving endothermic reactions isn’t.

    Imagine dumping RTG heat using heat and convection to suck in bulk Titan atmosphere and drive endothermic chemical reactions.
    OR
    Imagine dumping RTG heat and using catalysts to drive endothermic reactions-
    generate lighter-than-Titon-air hydrogen and heaver-than-Triton-air Ethane.

    Dumping RTG heat via a catalyst and endothermic reaction would give a Triton probe the capacity to generate (and normally vent) lighter than Triton-air and heavier than Triton-air reaction products. With a bit of ingenuity, that would become a balloon like lifting body above the probe, and a balloon like touchdown sensor below the probe.

    • Adam June 28, 2019, 19:12

      Hi Hal
      You probably didn’t mean to write “Triton” rather than “Titan” but a near vacuum montgolfiere balloon on Triton would be a sight to see. JP Aerospace are planning a balloon to reach 100 km on Earth, which is surely as wispy as Triton’s atmosphere, so maybe? The current record is 63 km IIRC.

  • Alex Tolley June 28, 2019, 12:31

    I would be interested in knowing how autonomous this flyer will be. Will it control its own flight, using imaging/radar to control its navigation and select a landing site for each sample collection and overnight charge? From experiments I’ve seen, we are already pretty close to much of that capability. Will mission control just supply the way points and possible interesting landing targets and let the flyer do the rest?

    The images and science returns will be fascinating.

    • Enzo June 28, 2019, 16:02

      Given the time lag, I expect that the team might select the general direction and/or possible target destination based on previous flight. However all the details of navigating there, finding a safe landing place and actually land would be up to the drone.
      Flying mostly over the dunes should simplify things.

      I have mixed feelings about Dragonfly : I’m happy that’s not the usual Mars mission but I’m disappointed that, after such a long design and travel time we are going to miss the lakes. This probably means I won’t see that in my lifetime.

  • wsguerin June 28, 2019, 13:09

    I haven’t seen mention of flying to any of the methane lakes, did I miss that?

    • Paul Gilster June 28, 2019, 14:45

      Dragonfly will land during northern winter, when the lake region is dark. The spacecraft also will not have a sightline back to Earth during this period, so the equator is a pragmatic choice to ensure good science and the necessary communications.

      • Charley June 29, 2019, 16:09

        “Dragonfly will land during northern winter, when the lake region is dark. “, when the lake region is dark… what does that mean? That the lake region is frozen ?

        • Paul Gilster June 29, 2019, 16:27

          It means that Titan’s north polar region will be in winter darkness when Dragonfly lands on Titan.

          • torque_xtr July 2, 2019, 13:58

            The photos of Titan’s crescent are telling that Titan may have gorgeous white nights. And, more inportantly, perpetual twilights in polar winters. Maybe even winter solstice pole it is lit well enough for advanced camera to take shots and navigation info. At least, “civil twilight” zone there surely extends well past polar circle.

            So if Dragonfly runs on RTG, maybe it’s not out of question for it to fly into polar winter zone. And even if it is confined to equatorial belt, maybe it will find some small lakes there.

            https://scitechdaily.com/images/Crescent-Titan-by-Jason-Major.jpg

          • torque_xtr July 2, 2019, 14:14

            In addition, Kraken Mare southern shore is below 60 degree northern latitude, and Sun’s declination in 2034 will be -25 deg and rising, if I fugure this correct. So the days will be short on the shore but not sunless.

          • Charley July 3, 2019, 12:01

            “Dragonfly will land during northern winter, when the lake region is dark. “, will the lake region be frozen in Titan’s north polar region when Dragonfly lands on Titan ?

            • Paul Gilster July 3, 2019, 15:13

              The lakes could be a mix of methane ice and liquid methane during winter, if I’m not mistaken. Frozen methane is denser than liquid methane, so much of whatever ice forms should sink.

    • Enzo June 29, 2019, 0:17

      The mission Titan-Mare was supposed to land on Ligeia Mare, before the northern hemisphere winter. That was the last opportunity for a long time.
      Launch in 2016, arrival in 2023.
      Instead NASA selected yet another Mars mission, Insight.

      • Ashley Baldwin) July 1, 2019, 18:33

        Or lack of Insight.

        Still hasn’t managed to hammer it’s heat sensor mole in more than a few inches and has recorded just one ( very) faint burp of a “Marsquake” since operational. Not much to show. For an undersized planet with a long since frozen undersized iron core, combined with lack of any signs of tectonics ( ever) or vulcanism ( for geological ages) , it doesn’t exactly take a huge leap of logic to see why.

        Two years behind schedule and $150 millions over budget.

        It’s certainly given me an insight . Into NASA decision making, if not Mars’ dead interior.

  • Robert June 28, 2019, 14:11

    It seems very depressing to me that this the limit of technology we will have actually deployed in 2034. I would have expected by 2034 we should have the capability to assemble a much better probe and get it there in a matter of months all done by a team of graduate students at a cost available to a university research team.

    • Patient Observer June 29, 2019, 19:10

      I agree. If propulsion technology has not advanced in the next decade (thinking serious nuclear-electric) to allow relatively fast missions with significant payloads to the outer planets then interplanetary (much less interstellar) exploration will remain highly limited. These 10-15 year missions carrying tiny (albeit still highly function given the size) payloads just won’t cut it for us oldsters. Wasn’t SpaceX suggesting crewed missions to Titan in the relatively near future? Sure, it had to be hype but is there not some reality there as well? Not to go political but the funding for just one “humanitarian” BS war/regime change could turn hype into something as inspiring as the Apollo missions.

  • Andrew Palfreyman June 28, 2019, 15:32

    Yet again no instrumentation to detect cells themselves.

    • Adam June 30, 2019, 16:51

      Hi Alex
      How would you culture alien cells? I suppose a microscopic view might be useful, but what would be the natural size scale for “azotosome” based cells?

  • John Sheff June 28, 2019, 16:39

    Would this be a direct flight to Saturn or make use of a Jupiter gravity-assist? What is the launch vehicle? Will there be a communication relay orbiter circling Titan?

  • Antonio June 28, 2019, 17:01

    Does anybody know which launch vehicle will they use?

    • Alex Tolley June 28, 2019, 22:54

      I would bet SLS. Hasn’t NASA pretty much mandated this?

    • Ashley Baldwin) June 29, 2019, 7:32

      I’m guessing at either a ULA Vulcan or Blue Origin’a New Glenn. The latter especially as it’s three stage version has a cryogenic upper stage with the kind of ISP necessary throw a probe to the outer solar system.

      Atlas V and Delta IV heavy will be long gone by launch in 2026 and hopefully the development and maturation of these two new launchers will have passed uneventfully .

      As to the Falcon Heavy ( with aome sort of booster , like the Star 48 solid rocket upper stage ) the question will be:

      1/ Will it have been supplanted by SpaceX’s larger launcher by then . As SpaceX tend to be rather optimistic with their deadlines , I’m guessing the Heavy will still be around in 2026 – more mature than either the Vulcan or New Glenn. And :

      2/ If so, will the Heavy have received the requisite Nasa Accreditation to carry the RTG power source this mission requires ? Not an easy or cheap process for just the one launch.

      SLS , even if operational in an iteration with a suitable cryogenic upper stage ( ICPS ,EUS et al) , would be deemed too expensive for a New Frontiers class mission.

      • Alex Tolley June 29, 2019, 21:41

        SLS (…) would be deemed too expensive for a New Frontiers class mission.

        You make a valid point. SLS launch costs alone would exceed the Frontiers entire mission budget.

        • Gary Wilson June 30, 2019, 20:34

          This is one of the many problems with SLS. How do you budget the launch cost into the mission cost when each SLS launch will be between 1 and 1.5 billion dollars? It’s ludicrous for most unmanned science missions. This system should be re-thought before it is entirely too late. It is going eat NASA’s budget alive. Completely unrealistic. Why does NASA think Elon Musk has spent so much time and effort on reducing launch costs with re-usable rockets? Time to join the 21st century NASA.

          • Alex Tolley July 1, 2019, 11:21

            This system should be re-thought before it is entirely too late.

            SLS is a pork barrel jobs program. (As was Aries I & V before it). It really is high time that we let commercial interests take over development of suitable hardware and let competition drive performance and cost. [As a side note, I really wonder if the US could recreate the sort of development and manufacturing drive that helped win WWII. As usual, Arthur C Clarke wrote a parody of government driven weapons development in the Vietnam war with his short story, Superiority.]

            I really hope that the “off the shelf” parts approach to building Cubesats eventually influences other projects. Standard platforms for robotic spacecraft and landers, with custom equipment where needed could help drive down costs and increase volume. If NewSpace companies can really drive down launch costs, we could get a lot more done for the funding.

      • Ashley Baldwin) June 30, 2019, 5:23

        Looking at the provisional flight plans for Dragonfly , there are no Jupiter Gravity Assist options to the outer solar System till the mid 2030s. There are various Venus/Earth assists available from 2025 through to 2028 with the optimum in terms of time and arrival velocity / angle of insertion being in 2026 with a EVEE assist regime ( with the minimal planetary approach distance allowed for an RTG carrying Probe) ,giving an overall flight time of about 8.5 years . This assumes the use of a “mid performance ” Atlas V 411 EELV as per the initial New Frontiers Announcement of Opportunity. The flight time to Saturn from Earth after the final Earth gravity assist would be just 3 years and nine months.

        How the newer launchers available at that time might impact the flight time I’m uncertain , though I would hazard not a lot.

        By way of comparison a direct flight option would require an initial launch energy, C3, of 137 kms2/S2. The Block 1 SLS could provide this for a maximum 2 tonne starting payload mass , with a final flight time similar that From the final Earth Gravity Assust of the EVEE route. Whether this would ve viable is uncertain however, given the large amount of monopropellant that would be required to decelerate on arrival from the higher resultant transfer velocity.

        • Patient Observer June 30, 2019, 8:24

          This is an interesting discussion. Is the assumption that the probe will enter Titan’s atmosphere without any braking? The atmosphere is much more extended than Earth’s suggesting a higher entry speed is possible. A direct entry would likely mean that a precision landing beyond simply being in the equatorial region would be impossible unless Dragon Fly could be deployed during the decent. Will stop speculating now.

          • Ashley Baldwin) July 1, 2019, 18:49

            The Dragonfly/carrier craft would use its onboard propulsive system to decelerate enough to be first captured by Saturn’s gravity. It would then using multiple flybys of both the planet and Titan itself to further reduce its velocity enough to allow the probe to be “injected” safely onto the moon . The same as with Huygen’s/Cassini – though likely easier as the carrier craft doesn’t have to then go on to perform a 13 year survey of the system ! Given Titan’s dense atmosphere, unlike Mars, the lander could reach the surface safely and simply with parachutes . As with Apollo returning to Earth. Without recourse to fancy (~ expensive & risky ) retropulsion.

  • P June 28, 2019, 20:40

    This is a brave choice. Its risky but that’s fine.
    I just wish there was some way to get some ice giant flyby action on a Discovery class budget. I also wish we could start to include some large ion thrusters on outer system missions to reduce transit times, but….$$$ I guess.
    Its going to be a long wait.

    P

    • Ashley Baldwin) June 30, 2019, 5:55

      They’ve done an Ice Giant flyby with Voyager 2. The various options currently under consideration by the Nasa OPAG ( Outer Planets Advisory Group – well worth googling as they have loads of Ice giant mission concept work presentations ) are all flagship orbiters. With or without SLS and with launch Windows opening from 2028 to make use of mid 2030s Jupiter gravity assists . With 8-10 year transit times.

      Ion engines are still limited in the outer solar system because of the electrical power they require to operate . In the Kilo Watt range. Which means solar electric , something that is obviously drastically reduced further away from the Sun – inversely proportional to the square of the distance .( at 5 AU Jupiter the solar flux is thus 1/25 than at 1 AU, falling to about 1/90 at Saturn) . Solar cell performance continues to improve in efficiency but stil falls dramatically at low illuminations and low temperatures ( so called “LILT”). To date NASA’s have not trusted the improving technology beyond Jupiter ( Juno) – the “Enceladus Life Finder” ,ELF concept that initially competed with Dragonfly – and which proposed using solar power rather than an RTG – was rejected for this very reason.

      The long term plan ( driven by NASA Glenn who lead the way in thus area ) is to utilise “solar electric staging” for outer solar system missions . After an initial conventional launch , a large solar array powered ion engine ( 15 KW ?) will continuously boost a Probe , perhaps as far out as 4 AU , before being discarded when no longer efficient . The rest of the now ( significantly ) foreshortened flight would be in conventional “cruise” mode.

      In this way , even a workhorse Atlas V launcher could be supported to get a Cassini mass flagship probe to Saturn in less than six years. ( cf 8.5 years for the same launcher to get the much smaller Dragonfly there, even with multiple Earth/Venus gravity assists )

      • Bill June 30, 2019, 22:38

        Two advancements could make a dramatic difference in future missions to the outer system. Magnetoshell aerocapture and kilopower. Unfortunately they won’t be available for a decade or more given current rates of progress but they will gave a dramatic impact when they do become available.

        • Ashley Baldwin) July 1, 2019, 19:07

          I think aerocapture becomes viable for Uranus and especially Neptune.

          With a decent launcher and gravity assists, transit times of circa 8 years ( or much less) are practical and economic out to Saturn.( whilst still allowing any RTG power source to offer for a viable primary and extended missions) . Solar electric staging will likely help further, is nearly mature and low risk .

          Beyond Saturn, the sort of transit velocities required to hold to this 8 year timescale require a large ( and expensive ) launcher with a sizeable amount of on board propellant, massively increasing the “wet” – non payload – mass of probe , in order to allow an orbital insertion burn and subsequent in system grand “tour”. That adds up to tonnes of propellant – six tonnes plus. ( bearing in mind too that both Uranus and Neptune have much lower gravity than Saturn) .

          Aerocapture certainly looks an attractive , nee essential for Neptune atleast, where even SLS can’t get you there in under ten years.

      • Ashley Baldwin) July 2, 2019, 18:33

        The general consensus from OPAG is that the Ice Giants can’t be done for less than $2 billion. Flagship class and way, way beyond New Frontiers . That’s with a straw man payload too and no better launcher than an Atlas V 551 . Which gives a transit time well in excess of eight years to Uranus ( and ten to Neptune) even with Jupiter gravity assist windows opening again for Uranus and Neptune from 2028.

        $1 billion plus SLS takes a year or two off transit time .

        For a comprehensive instrument payload , including an atmospheric entry probe , the budget is up beyond $3 billion. All singing and dancing – $4 billion.( excluding launcher ) – that’s a lot, but actually less in adjusted $s than Cassini. Collaboration with other burgeoning international space agencies would certainly help mitigate this .

  • Michael June 29, 2019, 5:22

    It would be nice if this dragonfly could drop off reflectors on the surface, with these reflectors we could map the movement of the ground from orbit with very high precision and map the crust and ocean beneath.

  • Ashley Baldwin) June 29, 2019, 7:46

    I think it speaks volumes for the perceived maturity of drones that Dragonfly has even been selected. The approval process for New Frontiers programme is extended , strenuous ..and conservative . So a “yes” represents a big vote of confidence .

    Exciting times ahead arising from uncertainty.

    It wasn’t that long ago we were all worrying when the next outer solar system missions were going to occur, if ever, post Cassini/Juno. Now we have Europa Clipper, JUICE AND now Dragonfly, to keep us all occupied for a decade and some between them from the late 2020s.

    Dirty snow balls and space boulders, the “low lying fruit”, are fine as far as they go ( which has seemed just about forever given they have been the staple of budget space programmes for some time now ), but the “planet” is now being well and truly put back into “planetary” science .

    Where it belongs. Roll on the Ice Giants.

  • steven Torry Rappolee June 29, 2019, 16:10

    Imagine if you built this helicopter into a floatplane
    You could do the Titan lake science proposed for the sub and floater missions ( TIMED)
    https://yellowdragonblog.com/2019/06/29/titan-dragonfly-2-0-a-flying-titan-lake-lander/

  • Charley June 30, 2019, 0:59

    The first immediate thought that came to my mind the moment I saw the model that they portrayed the land is to be, was what kind of sticky situations, could it find itself in once it touched down.
    The first that came to mind was: what would happen if the lander landed at a place where there was an uneven surface and it tipped itself over onto its side? How could the thing possibly right itself in such a event? Would that be the end of the mission?
    In the event that there was a tip over to the side would the rotors be brought to an immediate halt, or would they possibly be rotating and conceivably shear off the blades on contact with the surface?
    Is there any expectation that this craft will have both downward looking radar and artificial intelligence sophisticated enough to discern a dangerous topology on a potential landing site? Radar, what little I do know about it seems to require a lot of power and is usually of a significant mass/volume situation which might preclude it being on board.
    Finally, it would seem scientifically advantageous to have a camera to look down on the terrain below, while in flight, just to get more info out of your mission. Once you had acquired the data you could send it on to earth at an opportune transmission window.

  • Rob Flores June 30, 2019, 20:36

    I really think a Semi-Rigid Airship design would carry less risk and
    would be more flexible.
    1) Sampling pods could be lowered to surface, retract when done.
    multiple pods for redundancy.

    2) very simple control systems. easy to set a fail safe mode.

    3) Soft shell/Hard Toroid O2 tanks for methane combustion power generation, and central Hydrogen lifting Gas compartment, would give a tremendous endurance.

    4) hover over interesting surface features without disturbing them.

    Drawback is Aero braking design.
    a heatshield and gyro system would have to designed for
    a 12 foot tall 5 foot diameter craft.

    • Alex Tolley July 1, 2019, 11:06

      Endurance in the air is the only advantage of a lighter-than-air craft. There is a reason drones are dominating the on Earth these days, rather than airships/blimps for almost any purpose, including package delivery. Lack of maneuverability and susceptibility to wind are major impediments to using such craft. In the denser atmosphere of Titan, a propeller driven craft seems to make much more sense assuming the power to fly it is available.

      There is obviously going to be a lot of design and test work to be done to minimize all failure modes that the engineers can dream up. I would be interested to know how they intend to simulate Titan’s dense atmosphere for flight tests. Maybe just suspend the craft on a tether to reduce the weight to simulate both lower surface gravity and the better lifting power of the props. The computer animation and stills certainly show quite small propellers compared to a drone flying on Earth.

      • Ashley Baldwin) July 1, 2019, 15:11

        The key will be the moving parts with a rota powered craft. With extended periods of inactivity on the ground in between too. In ambient temperatures falling to -190C. Be interesting to see what lubricant they use.

        • Alex Tolley July 1, 2019, 19:10

          Bearings and lubricants exist for cryogenic rotary pumps, especially the pumps for rocket engines with cryofuels. If inactivity is an issue while recharging, maybe the solution is to idle the motors to prevent any freezing up. Alternatively, perhaps the waste heat from the RTG could keep the moving parts warm enough. It would certainly be fun to work on the engineering problems for such a flyer. I hope some of these issues and their solutions are made public if this project makes it all the way to launch.

      • Rob Flores July 2, 2019, 17:30

        To counter Some of A. Tolley’s comments on airship design

        1) Airships on the Earth have to contend with very high winds compared to Titan near surface winds.

        2) an airship at 500 Ft, on Titan being 5ft x 12ft, will have plenty of space to get itself out of a Wind Induced Problem.

        3) Airships on the Earth encounter hazards because of their
        proximity to surface . There is no need to bring said airship
        to near surface, if your probe package is lowered to the surface.

        4) You can use a dual propulsion system for redundancy.
        Propeller driven, The secondary propulsion can
        be a very small Pulse engine like the V1, with the engine contained in a central shaft, with methane intake up front.

        5) With proper Automated attitude controls, you can use Titan’s winds to assist travel to SOME of your destinations,

        I agree that the most of the atmosphere of Titan is no place for an
        airship, but the main difficulty IMO is delivering such a craft
        to near surface where winds are tamer.

  • Steve Muise July 1, 2019, 12:04

    Given that we only have 90 minutes of data from one spot on the surface of Titan (from Huygens) I’m not sure we understand enough about the surface conditions to successfully and repeatedly fly on Titan. Once DragonFly is on the surface the learning curve may be steeper than anticipated. I personally think that a stationary lander would make more sense (at least from a risk perspective).

    That being said, fortune favors the bold, and I look forward to seeing this mission in action!

  • Gary Wilson July 1, 2019, 18:03

    Dragonfly is a tremendous opportunity, but also a tremendous risk. Steep learning curve indeed Steve. Given the long preparation and flight time is this the best use of this amount of money and resources? Naturally we will be in awe if it is a resounding success but I agree with Steve. We don’t know enough about the Titan surface. Dragonfly could end up trapped in the Titan equivalent of quicksand.

  • Charley July 2, 2019, 11:29

    OK, I’m officially confused here. I’ve been reading comments and there’s a lot of discussion about not going to the lakes in the northern region because Titan will be dark in the northern hemisphere. Is there some pressing reason for having to go in 2034? I mean, couldn’t NASA wait till Saturn has returned on the other half of its orbit, so that the North region of Titan will be in the sunlight? It’s like they got a go, then, or they can’t go, I assume there’s no real reason (programming funding perhaps?) that you can’t wait for that launch window-is there?

    • Alex Tolley July 2, 2019, 14:02

      Saturn’s orbital period is 29 years, so a 1/2 Saturn year to get back to summer is at least 15 years away. That is a long time extra to wait. Why not do a flight to arrive asap, then, if the science looks really interesting, plan on other trips including a lake trip, probably with more advanced technology?

  • Ashley Baldwin) July 2, 2019, 12:57

    The timing of the mission was governed by the next New Frontiers bidding round and the solid Dragonfly bid. “Ocean World’s” was (very) belatedly added to the potential areas for consideration, so clearly the timing was deemed auspicious. If I recall the assessment of these bids allocates 40% of the overall marks to science return . So the NASA assessors obviously thought that launching within this window was well worth the return. They’ve already considered, and rejected, lake focused missions before ( TiME) when the opportunity was there. In terms of risks, these will have been viewed with the available science for Titan from Cassini, and deemed a fair trade off .

  • Mike Serfas July 7, 2019, 12:20

    You might find this interesting: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3025523/ It is apparently fairly simple for E. coli to evolve resistance to at least brief treatments (15 min) with 2 GPa pressure. Right now there is a gap between the 1 GPa maximum reachable on Earth in ocean trenches, where life seems to do pretty well, and the 11+ GPa that would be found at the bottom of Titan’s ocean. (The temperature might also be well under 0 C due to the pressure and solutes) Could Earthly life tap into the resources and geologic features at the bottom of Titan’s sea? Might Dragonfly find fossils embedded in pebbles of igneous ice in Titan’s riverbeds?

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