NASA's Next Big Mission: Dragonfly to Saturn's moon Titan

[lpetrich]

NASA's Dragonfly Mission to Titan Will Look for Origins, Signs of Life | NASA - has a simulation video of the spacecraft's landing.

Dragonfly will launch in 2026 and arrive in 2034. The rotorcraft will fly to dozens of promising locations on Titan looking for prebiotic chemical processes common on both Titan and Earth. Dragonfly marks the first time NASA will fly a multi-rotor vehicle for science on another planet; it has eight rotors and flies like a large drone. It will take advantage of Titan’s dense atmosphere – four times denser than Earth’s – to become the first vehicle ever to fly its entire science payload to new places for repeatable and targeted access to surface materials.

...
Dragonfly took advantage of 13 years’ worth of Cassini data to choose a calm weather period to land, along with a safe initial landing site and scientifically interesting targets. It will first land at the equatorial “Shangri-La” dune fields, which are terrestrially similar to the linear dunes in Namibia in southern Africa and offer a diverse sampling location. Dragonfly will explore this region in short flights, building up to a series of longer “leapfrog” flights of up to 5 miles (8 kilometers), stopping along the way to take samples from compelling areas with diverse geography. It will finally reach the Selk impact crater, where there is evidence of past liquid water, organics – the complex molecules that contain carbon, combined with hydrogen, oxygen, and nitrogen – and energy, which together make up the recipe for life. The lander will eventually fly more than 108 miles (175 kilometers) – nearly double the distance traveled to date by all the Mars rovers combined.

Goddard's Contributions to NASA's New Dragonfly Mission | NASA - some chemical-analysis devices: a mass spectrometer for molecules and a gamma-ray and neutron spectrometer for elemental composition.

Dragonfly - its home page.
Why Titan? - that moon has lots of interesting surface features.
What Is Dragonfly? - the spacecraft will have a 2*2*2 rotor configuration. It will be powered by a RTG that will charge a battery for powering its flights.

 Dragonfly (spacecraft)

 

[DBT]

Looks like an interesting mission. I wonder why they chose that rather than a lander on Europa (or a close flyby) to sample the material ejected from the subsurface ocean, with perhaps a chance at finding signs of life?

 

[hurtinbuckaroo]

Looks like an interesting mission. I wonder why they chose that rather than a lander on Europa (or a close flyby) to sample the material ejected from the subsurface ocean, with perhaps a chance at finding signs of life?

“ALL THESE WORLDS ARE YOURS - EXCEPT EUROPA. ATTEMPT NO LANDINGS THERE.”

 

[Jimmy Higgins]

Looks like an interesting mission. I wonder why they chose that rather than a lander on Europa (or a close flyby) to sample the material ejected from the subsurface ocean, with perhaps a chance at finding signs of life?

“ALL THESE WORLDS ARE YOURS - EXCEPT EUROPA. ATTEMPT NO LANDINGS THERE.”

Lest surely you will die.

*time passes*

They go to Europa and don't die, but get casted out of the solar system.

*lots of time passes*

He meant a spirtual death!

 

[lpetrich]

Looks like an interesting mission. I wonder why they chose that rather than a lander on Europa (or a close flyby) to sample the material ejected from the subsurface ocean, with perhaps a chance at finding signs of life?

Europa has a big problem: it's much more difficult to land on than Titan is. That's because Titan has a thick atmosphere and Europa has essentially no atmosphere - Detection of an oxygen atmosphere on Jupiter's moon Europa | Nature - surface pressure about 10^(-11) Earth's.

So for Europa, one will have to match velocities and go into orbit around it, and then drop a lander. Going into orbit around Europa will require several km/s of delta-V, and one will need a nuclear-powered electric rocket engine for that. The last bit of the way is about 1.4 km/s of delta-V, comparable to landing on our Moon.

But for Titan, there is no such difficulty. All that is necessary is being able to hit the moon's atmosphere at several km/s and survive doing so -- an ability that has been abundantly demonstrated for Venus, the Earth, Mars, Jupiter, and even Titan itself.

 

[DBT]

Looks like an interesting mission. I wonder why they chose that rather than a lander on Europa (or a close flyby) to sample the material ejected from the subsurface ocean, with perhaps a chance at finding signs of life?

Europa has a big problem: it's much more difficult to land on than Titan is. That's because Titan has a thick atmosphere and Europa has essentially no atmosphere - Detection of an oxygen atmosphere on Jupiter's moon Europa | Nature - surface pressure about 10^(-11) Earth's.

So for Europa, one will have to match velocities and go into orbit around it, and then drop a lander. Going into orbit around Europa will require several km/s of delta-V, and one will need a nuclear-powered electric rocket engine for that. The last bit of the way is about 1.4 km/s of delta-V, comparable to landing on our Moon.

But for Titan, there is no such difficulty. All that is necessary is being able to hit the moon's atmosphere at several km/s and survive doing so -- an ability that has been abundantly demonstrated for Venus, the Earth, Mars, Jupiter, and even Titan itself.

So degree of difficulty is the reason for NASA taking the option of Titan over Europa?

 

[skepticalbip]

Looks like an interesting mission. I wonder why they chose that rather than a lander on Europa (or a close flyby) to sample the material ejected from the subsurface ocean, with perhaps a chance at finding signs of life?

Europa has a big problem: it's much more difficult to land on than Titan is. That's because Titan has a thick atmosphere and Europa has essentially no atmosphere - Detection of an oxygen atmosphere on Jupiter's moon Europa | Nature - surface pressure about 10^(-11) Earth's.

So for Europa, one will have to match velocities and go into orbit around it, and then drop a lander. Going into orbit around Europa will require several km/s of delta-V, and one will need a nuclear-powered electric rocket engine for that. The last bit of the way is about 1.4 km/s of delta-V, comparable to landing on our Moon.

But for Titan, there is no such difficulty. All that is necessary is being able to hit the moon's atmosphere at several km/s and survive doing so -- an ability that has been abundantly demonstrated for Venus, the Earth, Mars, Jupiter, and even Titan itself.

So degree of difficulty is the reason for NASA taking the option of Titan over Europa?

Just personal opinion but I think it was that they could try a novel 'helicopter' to move the sensors around to different areas for sampling. NASA loves doing novel, untested things to expand their list of available, tested techniques. Look at the wide variety of landing techniques used for landings on Mars.

 

[bilby]

When the US government is sending an exploration mission to somewhere which is awash with hydrocarbons, I have to assume that if they do find life there, they plan to declare war on it.

 

[skepticalbip]

^^^
And if there is no life, declare it the fifty-first state without having to waste ammunition.

 

[lpetrich]

So degree of difficulty is the reason for NASA taking the option of Titan over Europa?

Yes, the necessary delta-V bites very hard. For Europa, one has two options:

1. A nuclear-electric rocket system that can deliver sufficient delta-V (velocity change)
2. A lander that can survive impact at several kilometers per second

While for Titan, one can do what one did for the Huygens lander.

About the first option, both nuclear reactors and electric rocket engines have been flown, but not a combination that could deliver sufficient delta-V.

About the second option, penetrator landers have been worked on, but none have ever been flown.

 

[DBT]

So degree of difficulty is the reason for NASA taking the option of Titan over Europa?

Yes, the necessary delta-V bites very hard. For Europa, one has two options:

1. A nuclear-electric rocket system that can deliver sufficient delta-V (velocity change)
2. A lander that can survive impact at several kilometers per second

While for Titan, one can do what one did for the Huygens lander.

About the first option, both nuclear reactors and electric rocket engines have been flown, but not a combination that could deliver sufficient delta-V.

About the second option, penetrator landers have been worked on, but none have ever been flown.

I imagined something like an armoured 'lander' for Europa that is designed to crash into an ice fissure at full speed, like a bunker buster, straight into the underlying ocean while trailing a communication cable to transmit information from the surface to an orbiter and Earth, lights, camera, sensors....

 

[bilby]

So degree of difficulty is the reason for NASA taking the option of Titan over Europa?

Yes, the necessary delta-V bites very hard. For Europa, one has two options:

1. A nuclear-electric rocket system that can deliver sufficient delta-V (velocity change)
2. A lander that can survive impact at several kilometers per second

While for Titan, one can do what one did for the Huygens lander.

About the first option, both nuclear reactors and electric rocket engines have been flown, but not a combination that could deliver sufficient delta-V.

About the second option, penetrator landers have been worked on, but none have ever been flown.

I imagined something like an armoured 'lander' for Europa that is designed to crash into an ice fissure at full speed, like a bunker buster, straight into the underlying ocean while trailing a communication cable to transmit information from the surface to an orbiter and Earth, lights, camera, sensors....

Europa's ice is estimated at 19 to 25 kilometres thick. I haven't done the maths, but I seriously doubt that an impact fast enough to break through even 1km of ice would be survivable for any kind of instrumentation we are able to engineer today.

NASA rather euphemistically refer to 'lithobraking' to describe a spacecraft being decelerated by contact with a solid surface. Europan ice isn't significantly less tough than the Earth's crust - imagine designing a space probe to sample Earth's mantle by crashing all the way through the crust at high speed. It's a big ask, even if you get a head start by crashing into the Marianas Trench.

Europa's ice and the Earth's crust are quite similar in both toughness and thickness. And while ice does have a much lower melting point than rock, the lower temperatures on Europa make melting through a seriously difficult undertaking - not only do you need to concentrate enough energy to melt a hole, but you also need to prevent it from instantly freezing closed again. It might be easier to drill it as though it were rock. But that's going to need a lot of heavy equipment, and you're back to your delta-V problem.

Titan is a lot easier. Aerobraking is much cheaper than delta-V, and much less stressful than lithobraking.

 

[lpetrich]

I imagined something like an armoured 'lander' for Europa that is designed to crash into an ice fissure at full speed, like a bunker buster, straight into the underlying ocean while trailing a communication cable to transmit information from the surface to an orbiter and Earth, lights, camera, sensors....

Yes, a penetrator.

ESA funding a space penetrator, a science missile to bombard planets and moons - ExtremeTech
Why Slamming Penetrator Spacecraft Into Planets Makes Good Sense - VICE
Shows a penetrator being tested on a block of ice.

 

[DBT]

Europa's ice is estimated at 19 to 25 kilometres thick. I haven't done the maths, but I seriously doubt that an impact fast enough to break through even 1km of ice would be survivable for any kind of instrumentation we are able to engineer today.

That's why I mentioned fissures, perhaps forming at a point where the ice is not so thick. Maybe wave action or uneven thermal expansion due to tidal forces creating relatively thin sections of ice where fissures are forming.

Just speculation on my part. No doubt it's something NASA would consider.

 

[bilby]

Europa's ice is estimated at 19 to 25 kilometres thick. I haven't done the maths, but I seriously doubt that an impact fast enough to break through even 1km of ice would be survivable for any kind of instrumentation we are able to engineer today.

That's why I mentioned fissures, perhaps forming at a point where the ice is not so thick. Maybe wave action or uneven thermal expansion due to tidal forces creating relatively thin sections of ice where fissures are forming.

Just speculation on my part. No doubt it's something NASA would consider.

Well, just like the Earth's crust, there are fissures - but still there are kilometres of ice to get through. I can see a penetrator going through tens of metres; but thousands seems unlikely.

Even from the bottom of the Challenger Deep, it's still a long way down to the mantle.

 

[DBT]

Europa's ice is estimated at 19 to 25 kilometres thick. I haven't done the maths, but I seriously doubt that an impact fast enough to break through even 1km of ice would be survivable for any kind of instrumentation we are able to engineer today.

That's why I mentioned fissures, perhaps forming at a point where the ice is not so thick. Maybe wave action or uneven thermal expansion due to tidal forces creating relatively thin sections of ice where fissures are forming.

Just speculation on my part. No doubt it's something NASA would consider.

Well, just like the Earth's crust, there are fissures - but still there are kilometres of ice to get through. I can see a penetrator going through tens of metres; but thousands seems unlikely.

Even from the bottom of the Challenger Deep, it's still a long way down to the mantle.

No doubt, but it may be that there is an upwelling of ocean within fresh fissures. There is evidence of plumes, which indicates sufficient internal heat and pressure to drive material to the surface and beyond.

 

[DBT]

Article:

Is Europa's ice thin or thick? At chaos terrain, it's both!

The controversy over ice thickness:

''Among Europa scientists there are two warring factions: the thick-icers and the thin-icers. (I know science isn't really supposed to work that way, but all too often, it does.) The question is how thick is the ice shell that overlies Europa's subsurface ocean (the existence of which pretty much everyone agrees on). The thin-icers claim that the water comes very, very close to the surface, sometimes even melting through.''

''So for all of you people who were secretly hoping the thin-icers would win the argument because you are hoping to see humans send a probe onto Europa's surface and maybe even drill through the ice to its ocean, you have a consolation prize. The ocean's still deep below the surface, 10 to 20 kilometers, but if Britney and her coworkers are right, there very likely are liquid water lakes at only maybe 3 kilometers' depth. And water from those lakes has squirted upward, helping wet and break up Europa's crust all the way to the surface. The dark stains associated with chaos could well be the salts and other stuff that are dissolved in that lake water. So, land at Thera, and you might be able to taste Europa's ocean!''

 

[James Brown]

What about a radioactive sphere landed on Europa? It melts the ice and sinks down to the waters below. Then it opens its sensors and sees what it can see, transmitting the results to the orbiter overhead.

 

[Bomb#20]

NASA rather euphemistically refer to 'lithobraking' to describe a spacecraft being decelerated by contact with a solid surface.

Are they sure they don't mean lithobreaking?

 

[bilby]

What about a radioactive sphere landed on Europa? It melts the ice and sinks down to the waters below. Then it opens its sensors and sees what it can see, transmitting the results to the orbiter overhead.

I rather like this idea. A modified RTG could do a great job - and they are already designed to withstand crashing back to Earth in the event of a launch problem, so a fairly hard landing could be acceptable.

I suspect the big problem would be communication back to the orbiter - several km of ice is a pretty effective shield. And pulling a cable down from a 'base station' which remains on the surface would have issues as the water in the hole refreezes. Perhaps some kind of 'snow blower' - a pump that sprays the meltwater out of and away from the hole as it is drilled - could solve that problem; Though your probe would likely be instantly frozen in place once it breaks through the ice.