NASA Selects Dragonfly Mission To Titan
NASA Selects Flying Mission to Study Titan for Origins, Signs of Life, NASA
“NASA has announced that our next destination in the solar system is the unique, richly organic world Titan. Advancing our search for the building blocks of life, the Dragonfly mission will fly multiple sorties to sample and examine sites around Saturn’s icy moon.”
Is it going to be ‘It’s astounding’ or ‘It’s a god-awful small affair…’??
I bet it will be “exciting”.
I was initially expecting either a Mars methane announcement or a Sample Return probe.
Fingers crossed Dragonfly was able to show a low enough level of technical risk.
I hope so, but I’m afraid the process for Discovery and New Frontiers missions is rigged against the more ambitious proposals. The down select really is focused on the proposal with the lowest level of technical (cost and schedule) risk.
EDIT: Over the years is there a project, or projects, that you have in mind, that were downselected, perhaps in haste?
You’ve made that and similar comments many times, but I don’t think I get your point about how is the process ‘rigged’?
Isn’t downselect supposed to focus on the likelihood of project success? If a project fails because risk is insufficiently ameliorated, shouldn’t the project be on the 86 list? Are you saying that the proposer failed to sufficiently reduce known or predictable risk?
Or, are you pointing out that perhaps there are truly exciting and worthwhile projects where risk cannot be further reduced because one of the mission goals is learning more about risk?
Sometimes a more risky choice should be selected for non-cis-lunar space missions.
Otherwise if going the cheaper and easier route. Then all you get is missions to Mars and asteroids.
The Europa Clipper wasn’t selected, it was proclaimed by fiat by ex-representative John Culberson.
Europa Clipper was definitely selected, but not in the same way as a Discovery or a New Frontiers mission. It was the second highest priority in the last Decadal Survey, and to get there it was in competition with lots of other, good ideas (e.g. a Uranus or Neptune orbiter.) Without Mr. Culberson, it might have lingered on the waiting list for a few more years. But in one form or another, that’s been a high priority for the planetary science community for a couple decades. Now, the Europa lander, on the other hand, would have been a Culberson creation.
Serious question; does this mission selection choice go differently under Bolden than Bridenstine?
I’m sure these decisions are approved all the way up, but I think the actual choices happen at a lower level. Probably by Dr. Zurbuchen for the Science Mission Directorate and Dr. Glaze for the Planetary Science Division. I will say Dr. Zurbuchen is probably more inclined to consider novel approaches than many who have held his job in the past.
Well, in this case, it didn’t go the way I predicted. But the usual process was against it.
Specifically, the first (step one) selections are basically about the science, whether or not a proposal would do something really cool and interesting. There is some consideration of technical details; the proposal has to prove that it’s actually possible to achieve the stated goals. But for the initial (step one) proposal, you don’t need blueprints or anything like that. Just a convincing case that the mission is plausibly, within the cost and schedule requirements.
The down select, or step two selection, is different. It presumes that all the proposals which passed the step one selection are excellent, in terms of the planned science. The proposals do have to discuss the planned science, but that’s more of a confirmation of the previously reviewed goals. The step two reviews tend to be more focused on the technical details. Given two proposals, each of which are assumed to be scientifically excellent, which one is most likely to meet the cost and schedule requirements?
So, once a proposal has gotten over the science or coolness hurdle at step one, the step two selection does tend to favor the least ambitious mission. InSight rather than the Titan boat proposal is one example. Fortunately, in this case that isn’t always the rule.
Ambitious is not necessarily the opposite of technically competent. The TMCO reviews are meant to determine whether a proposal team is capable of managing all risk aspects — hardware, software, financial, personnel, management, and so on — to the satisfaction of a group of gimlet-eyed experts in the various fields.
Kudos to the Dragonfly team for passing that test, and best wishes for mission success!
I’m not sure I agree. Ambitions tend to push the limits, either in cost, schedule, technology development or simply trying something new and different. That doesn’t guarantee they’ll get bad marks in a TMCO review, but it definitely doesn’t help. Also, those reviews normally use parametric cost models, and that’s extrapolation from past missions. That means they give very uncertain results for idea which are new and different, and those results tend to be interpreted conservatively. (As in, “We don’t know but it could be really expensive” being translated into “it will be really expensive.”)
It may be very different in your field; in mine, some of the most scientifically compelling missions had instrumentatrion and spacecraft subsystems with very high TRLs, and it was just mission cost cap, launch vehicle, &c. that determined whether they were feasible. Sometimes, though, it was what level of risk assumption the agency would be happy with, and it was instructive to see at least one mission driven to low Class components to meet a cost cap, and in another case, the cost cap modeled on very high Class components. At least NASA was willing to consider both kinds of missions (and everything in between).
I think this may just be a matter of wording. I said “ambitious” and you’re saying “scientifically compelling.” I was talking about missions which are new, different, or in some way pushing the limits of what can be done within the cost cap and other restrictions. It is definitely possible to do excellent, compelling science without pushing those limits. And such a proposal would probably sail through a TMCO review. But a similar mission could, arguably, accomplish even more if it pushed the limits. But the rating for feasibility probably wouldn’t be as high.
Apparently not.
Which is something I am grateful for. I’m still concerned about the process, but I think it got it right this time. But Zibi is going to be insanely busy with Dragonfly and the Europa Clipper instrument. I wish her the best.
I’d say Dragonfly must have had the higher risk with a very ambitious payload, challenging environment, nuclear safety, etc., but was chosen for excellent and exciting science (plus pizazz). After the selection celebration comes the realization of how much you have to deliver. Good luck to them!
Dragonfly! This is terrific news!
Bring China onboard to send 2 quadcopters!
Better, get China or somebody to send an orbiter with imaging radar and data relay to support and complement Dragonfly.
Speaking of which, what return data rate are they going to get out of that main antenna, which appears to be something like 1 meter in diameter?
There are quite a few details we don’t know, but… By 2034, the DSN 70-m antennas will have been decommissioned, and everyone is supposed to be shifting to Ka band instead of X band for downlinks. Assuming that and for a typical spacecraft’s radio and a 1-m antenna at Saturn, you’re looking at about 10 kbps. That can go up by arraying multiple 34-m DSN antennas.
From the looks of it, three of the four instruments should be relatively low data volume. The camera is going to be the big contributor. Again, I don’t know how aggressive their plans for data compression are. But that could mean a one-megapixel, color image every ten or twenty minutes of downlink. Don’t expect streaming HDTV video. I hope there will be video, but it’s probably going to be lower resolution, black and white and with lots of lossy compression.
They have enough on their plate without an external interface, ITAR restrictions, etc.
Very cool! This will be one challenging mission. Incredible if they pull it off… good luck APL!
Great choice!
Seven years to the launch and fifteen years from now to get to Titan. That will make me 81. Hope I’m still around then.
This is a good decision even without the cool factor, but cool factor it has; it’s a nuclear-powered drone on a moon of Saturn that has a thick atmosphere and lakes of liquid methane and ethane.
Now those are some phrases, “nuclear powered drone” just think of what non-techie people will imagine. “Lakes of liquid methane” which I knew before but I still cannot get that into my brain like a lake of water because it seems so unreal. Overall the non-HSF spacecraft are definitely a cool factor for NASA especially considering how far we’ve come with these missions since 1960s.
Dragonfly appears Plutonium-powered – makes sense for the environment – how does the reduction in Plutonium supply for RTG use affect this mission? I recall some discussion about a restart of the processing for space power use of plutonium. Interested in what the audience knows / opines. Thanks.
Plutonium production has been restarted, and they’ve even retooled to increase production (efficiency) over what was originally planned. It’s still a concern; we don’t have enough to put an RTG on every mission. Some of the concepts for Uranus and Neptune orbiters were considering four or five RTGs, and that raised some eyebrows. But Dragonfly is just using one MMRTG, and that’s not a problem. However, as I understand it, it won’t fly on RTG power. It uses the RTG to charge batteries while on the ground, then flies on battery power. Even on Titan, RTGs don’t provide enough watts per kilo for flight.
That how Curiosity does it. Curiosity uses the RTG to trickle charge the battery and everything runs off the battery.
Excellent explanation – makes total sense – sort of nuclear-powered, flying Tesla. Thanks.
This is a good choice although I would’ve sent at least two smaller drones, not one big one. Why put all your eggs in one basket?
I suspect it’s mostly cost, and probably availability of RTGs to a lesser extent. The science payload is already pretty tight, so I don’t think two, smaller drones would have been viable. Two of the currently proposed size would probably been over the New Frontiers cost cap. (And required two rather than one RTG, which might have been pushing it.)
I’m guessing the whole thing is sized around the MMRTG since it’s the one component that likely doesn’t scale very well due to the requirement that it be encased in such a way as to avoid releasing radioactive material due to a launch accident. But this is just a guess.
From what I hear (from a guy who knows a guy at APL), this entire thing hinges on the power system of an MMRTG coupled with a rechargeable battery to run the flight motors. That’s likely to be pretty challenging.
I found an interesting article by the Dragonfly project scientist, Ralph Lorenz.
http://dragonfly.jhuapl.edu…
and you’re basically right. It looks the rules would have allowed using up to three MMRTGs, but I really don’t think using more than one would have been selectable. The article also mentions using the waste heat to keep the electronics warm, but he wrote that using more than one would be a bit much.
One MMRTG provides 70 W by the time it gets to Titan. The 16-day day/night cycle puts a natural duration for charging the battery, and the battery capacity follows from that. But the RTGs and batteries don’t strike me as too challenging. RTGs have some quirks, but they’re fairly well known, and batteries are even better understood. I think their biggest challenge is the level of autonomy in flight. That’s doable, and they can draw heavily on experience with terrestrial quadcopter drones. But that strikes me as more difficult than the power systems.
I didn’t see anything about the overall architecture. How it it going to get to Titan? Will it be a direct descent like the more recent Mars landers or will there be an Titan orbiter/close flyby to deliver it to the vicinity of Titan and then release it for descent like Cassini or Galileo did for it’s probe.
We may find out more, now that Dragonfly has been selected. Proposals for this sort of thing are very carefully written and no one wants the reviewers to misunderstand something. Something inaccurate in a press release or a conference presentation might cause confusion, so people tend to keep quiet about the details until the mission is selected.
But the dots aren’t too hard to connect. The launch vehicle isn’t mentioned, and they probably don’t know what it is. For New Frontiers, the mission specifies the required capabilities and then NASA picks the rocket. They may have a short list (ok, they do), but the formal decision wouldn’t happen until late phase B. The dates give an eight year cruise, and a direct trajectory is a hair over six years. So a gravity assist of some sort must be involved. I believe I did hear it would be a direct entry. But I can also cheat. I know some of the people involved, they’ve been involved in many past proposals for Titan missions, and those studies have always come out favoring direct entry. The entry velocity would be a little under 10 km/s, which is about what Apollo did returning from the Moon. And Titan’s atmosphere has a large scale height, so the entry corridor is broad and easy to navigate.
By the way, the Galileo probe was released before orbital insertion. Huygens wasn’t because they needed Cassini in the right place to relay and direct entry didn’t give the right geometry.
Press conference mentioned one Earth flyby.
That depends on which launcher is selected for the mission. The baselined Atlas V 411 and a Falcon Heavy have a vast difference in the Delta-V available. Even greater difference if they used the Falcon Heavy in the fully expendable mode with a kick stage.
I haven’t seen anything about a baselined launch vehicle, and those options don’t make sense to me. The Atlas V is supposed to be retired in the early 2020s, and the launch date is 2026. The Delta IV heavy might still be around, but cutting a year or two off the cruise isn’t worth the extra cost. Falcon Heavy isn’t certified for launching RTGs (nor, I think, is the Falcon 9). That will probably change by 2026, but I can’t see NASA committing to using it at this point. I’m not sure what the certification process is; I guess it would be set by the Department of Energy. But I assume it’s something similar to flying astronauts or national security payloads. And, of course, Vulcan is even further from that, since it’s first flight isn’t until 2021.