Should Cassini have landed on a Moon?

[ProtoJeb21]

Some people are probably aware that Cassini is preparing for its "Grand Finale" in 2017, where it will flh between Saturn and the rings a few times before plunging into the planet's atmosphere. I do not like this at ALL.

The old "tradition" of burning up space probes once their missions are completed seems to be such a waste of effort, money, and onboard resources. Cassini costs several hundred million dollars, but NASA still wants it to burn up? Not that I'm completely against them, but it doesn't seem right for such a valued and valuable probe to go that way. We probably all know that Cassini is running low on fuel, so it will eventually have to be disposed of. But how about a better fate: landing on one of Saturn's low-gee moons?

With Cassini's new orbit, it's mainly impossible. However, landing or crashing onto one of Saturn's moons would've been a lot easier than getting into this "Grand Finale" orbit. Just look at this chart here:

https://en.wikipedia.org/wiki/Cassini–Huygens_retirement

If it was possible with Cassini's new orbit, it would have some restrictions. Only moons near or in the rings will be close enough for the probe to encounter them with its current situation. That still opens up the possibilities of landing on Pandora, Pan, Prometheus, Epimetheus, Atlas, Daphnis, and other small moons I forgot. Cassini's new orbit will bring the probe pretty close to at least one of thess moons, so encounters are possible. Then there is Mimas. Our favorite Death Star moon might be close enough to the rings for Cassini to encounter while making a rather small orbit change. It also has the lowest gravity of any object rounded by hydrostatic equilibrium.

Now with targets done, let's talk about physical limitations. Cassini has enough fuel left to land on any moon with less than 4% the gravity of Earth. All of the moons I mentioned fall well under this limit. In fact, Mimas has 0.00648 gees even though it has the most gravity of any moon I mentioned! The reason I chose such low-gee moons is that there has to be enough fuel to change Cassini's orbit and get captured by a moon. And with some of the moons hiding in the rings, there will be a lot of course corrections. Even if Cassini was chosen to land on a moon instead of the Grand Finale, then it would be able to land on any Saturnian moon (excluding Titan).

Finally, there is scientific interest. Mimas has the most scientifc (and citizen) interest of any of the mentioned moons, but the others tell an interesting story of the conditions in ring gaps. Personally, I'd recommend Mimas. But if the Grand Finale orbit was never made, NASA probably would've chosen either Tethys, Rhea, Dione, or Mimas itself.

Those are my thoughts, but what about yours? Would it really have been better for Cassini to land on a Saturnian moon than be cooked into Spacecraft Stew? I will eventually have a poll for this thread to get some statistics.

Edited July 9, 2016 by ProtoJeb21
Slight topic change

[max_creative]

Land!

On Minmus Mimas! Or any moon! It's still better than burning up! Jupiter has Europa so it's a contamination problem, but Saturn doesn't have anything! Plus, if there is ever another Saturn orbiter, then can land it right next to it, and after 150 years we have a long line of old spacecraft on one of Saturns moons! 

Basically, my opinion about this: 

LAND!

Edited July 7, 2016 by max_creative
Aaaaaaand... Out of rep...

[PB666]

Just now, max_creative said:

Land!

On Minmus Mimas! Or any moon! It's still better than burning up! Jupiter has Europa so it's a contamination problem, but Saturn doesn't have anything! Plus, if there is ever another Saturn orbiter, then can land it right next to it, and after 150 years we have a long line of old spacecraft on one of Saturns moons! 

Basically, my opinion about this: 

LAND!

Come agian?, i didn't catch your answer. 

Enceladas, NdG Tyson wants to go fishing there, you would want him to catch an oversized tardigras.

[kerbiloid]

If it lands on a moon, how should it aim its antenna to the Earth rather than a random direction? And if it couldn't communicate to the Earth, what's the point of its landing?

Afaik, Rosetta faces the same problem, and that's why it will be lost right after the landing.

P.S.
Leaving it on its orbit would probably mean that the future spacenauts will get a radioactive piece of metal to enjoy. As if they get a depleted fuel assembly from a reactor.

Edited July 7, 2016 by kerbiloid

[lugge]

Landing a probe, which is not designed for landing anywhere, on a moon?

Well, sounds cool, but unfortunately this is not KSP. And RL can be such a badass...

[kurja]

A probe with insufficient propellant to station keep it's orbit is going to land anywhere exactly how?

[kerbiloid]

5 minutes ago, lugge said:

Landing a probe, which is not designed for landing anywhere, on a moon?

NEAR Shoemaker

Edited July 7, 2016 by kerbiloid

[magnemoe]

You could probably land it on a tiny moon, problem is that you first had to intercept and orbit it who would use a lot of fuel

[Scotius]

Will you pay for it? Because time and effort of the team of highly qualified personnel needed to pull such stunt succesfully won't be cheap. And for what gain? Cassini is not a lander nor a surface probe. She doesn't carry any scientific instruments that would work on the surface and produce useful data. It will be an ridiculously expensive hunk of junk lying somewhere uselessly. I seriously doubt NASA will even consider sinking time, effort and money in such high-risk, low-reward endeavour.

[YNM]

Compared to landing something on Eros, landing things on Saturn's Moon(s) will be a more massive problem. The relative velocity that needs to be killed would be far larger than the one you saw for NEAR-Shoemaker. Combined with the fact that it's low on fuel it will be a problem, and in fact, a hazard. Better let the moon dance plunge it down the atmosphere.

EDIT : Found this wikipedia page: https://en.m.wikipedia.org/wiki/Cassini–Huygens_retirement

It seems like a slow landing will be dV-intensive... The ones with low dV would be smacking them right in the face.

Edited July 7, 2016 by YNM

[lajoswinkler]

It could only smack into something. That's not landing. If it was orbiting a small lumpy body, then it could, technically...

[Nibb31]

What makes you think it is capable of landing anywhere? Does it have an altimeter? Does it have enough dV? What purpose would it serve to land it?

It's really annoying to see people on a game forum think they have it all figured out better than those stupide folks at NASA/JPL who have been studying projects like these for decades.

Who do you think is better qualified for designing an end of life manoeuver? A bunch of kids doing a poll on the internet or a top notch team of some of the smartest astro-scientists in the world? Hmmm... 

[Rune]

5 hours ago, ProtoJeb21 said:

Some people are probably aware that Cassini is preparing for its "Grand Finale" in 2017, where it will flh between Saturn and the rings a few times before plunging into the planet's atmosphere. I do not like this at ALL.

The old "tradition" of burning up space probes once their missions are completed seems to be such a waste of effort, money, and onboard resources. Cassini costs several hundred million dollars, but NASA still wants it to burn up? Not that I'm completely against them, but it doesn't seem right for such a valued and valuable probe to go that way. We probably all know that Cassini is running low on fuel, so it will eventually have to be disposed of. But how about a better fate: landing on one of Saturn's low-gee moons?

It is possible with Cassini's new orbit, but has some restrictions. Only moons near or in the rings will be close enough for the probe to encounter them with its current situation. That still opens up the possibilities of landing on Pandora, Pan, Prometheus, Epimetheus, Atlas, Daphnis, and other small moons I forgot. Cassini's new orbit will bring the probe pretty close to at least one of thess moons, so encounters are possible. Then there is Mimas. Our favorite Death Star moon might be close enough to the rings for Cassini to encounter while making a rather small orbit change. It also has the lowest gravity of any object rounded by hydrostatic equilibrium.

Now with targets done, let's talk about physical limitations. Cassini has enough fuel left to land on any moon with less than 4% the gravity of Earth. All of the moons I mentioned fall well under this limit. In fact, Mimas has 0.00648 gees even though it has the most gravity of any moon I mentioned! The reason I chose such low-gee moons is that there has to be enough fuel to change Cassini's orbit and get captured by a moon. And with some of the moons hiding in the rings, there will be a lot of course corrections.

Finally, there is scientific interest. Mimas has the most scientifc (and citizen) interest of any of the mentioned moons, but the others tell an interesting story of the conditions in ring gaps. Personally, I'd recommend Mimas.

Those are my thoughts, but what about yours? Would it really be better for Cassini to land on a Saturnian moon than be cooked into Spacecraft Stew? I will eventually have a poll for this thread to get some statistics.

If by "land" you mean "crash and be disposed of, with no chance of ever being recovered", yeah, I guess it could do that on some moon. The thing is, they want to keep them from potential biological contamination, just in case we get to study them in the future, so they go for the gas giant, on account of it being very unlikely to have a niche where Earth bacteria can survive and foul up future measurements.

 

Rune. Soft-landing requires landing systems.

[kerbiloid]

57 minutes ago, Nibb31 said:

Who do you think is better qualified for designing an end of life manoeuver?

Those who have already performed a score of Oberth-Jool maneuvers and successfully landed a pack of SSTO's on Eeloo — or those who are messing for years with a single unmanned craft orbiting Saturn? It's obvious.

[Nibb31]

2 hours ago, kerbiloid said:

Those who have already performed a score of Oberth-Jool maneuvers and successfully landed a pack of SSTO's on Eeloo — or those who are messing for years with a single unmanned craft orbiting Saturn? It's obvious.

Please tell me you're joking.

[PB666]

2 hours ago, kerbiloid said:

Those who have already performed a score of Oberth-Jool maneuvers and successfully landed a pack of SSTO's on Eeloo — or those who are messing for years with a single unmanned craft orbiting Saturn? It's obvious.

Pride is nemesis.

[Omegagoldfish]

Firstly, Cassini is incapable of landing. It simply is not sturdy enough, and it lacks things like altimeters, landing legs, and any data collection devices for surface science. If we threw it into Saturn, there are many reasons why I approve of it.

1: It is one of the most Kerbal ways to dispose of old science probes.

2: It can give us actual data.

3: It removes almost any chance of biological contamination (some space probes had Earth bacteria within).

4: For some reason, I want space probes within every gas planet. One down, one pending, two to go.

2 hours ago, kerbiloid said:

Those who have already performed a score of Oberth-Jool maneuvers and successfully landed a pack of SSTO's on Eeloo — or those who are messing for years with a single unmanned craft orbiting Saturn? It's obvious.

If you're joking, that's hilarious.

If you're serious, let me laugh more.

[lugge]

40 minutes ago, PB666 said:

Pride is nemesis.

 

41 minutes ago, Nibb31 said:

Please tell me you're joking.

It's obvisious that kerbiloid is joking, isn't it? Why so serious?

[YNM]

3 hours ago, kerbiloid said:

Those who have already performed a score of Oberth-Jool maneuvers and successfully landed a pack of SSTO's on Eeloo — or those who are messing for years with a single unmanned craft orbiting Saturn? It's obvious.

But with that messing, they can literally flyby all the moon every other time _without costing any extra dV_ (which is what we tend to do).

I mean, oh come on, can you plan a few flybys of Duna, Kerbin and Eve, to then a few years later get a trajectory passing Jool on to Sarnus without spending any extra dV ? It's not easy doing these calculations. Very much not easy. Not even Scott Manley have the time to recreate Rosetta's trajectory. Same goes to Cassini. Or Juno. Or the upcoming Jupiter moon probe, for a fact.

Edited July 7, 2016 by YNM

[PB666]

1 hour ago, lugge said:

 

It's obvisious that kerbiloid is joking, isn't it? Why so serious?

Kerbiloid has said less enlightened things in seriousness. 

[kerbiloid]

Reading these posts, I'm already not sure if I was joking... Take it easy.

[Vanamonde]

Stick to the point, please. 

[55delta]

Some

12 hours ago, Omegagoldfish said:

3: It removes almost any chance of biological contamination (some space probes had Earth bacteria within).

I hate to break it to some people, but NASA doesn't want any of their orbiter probes to land anywhere. 

Orbital probes don't go through nearly the decontamination process that they put landing probes through. Since it turns out that some bacteria can survive some incredibly harsh conditions. NASA doesn't want to find that they are later either accidently mucking up an environment or that they are re-discovering life from Earth. Since there are moons around Jupiter and Saturn that could have their own life, NASA doesn't want their orbital probes to crash or land on those moons, on purpose or on accident. That's why the Galileo probes was sent into Jupiter and why Cassini will be sent into Saturn.

Sorry, but it's for future science. But we are eagerly awaiting some of the planned landing missions that are in the works. 

[Kryten]

The moons Cassini has enough thrust to theoretically land on have pretty poorly characterised orbits. Add the time lag, lack of any kind of altimeter, the small size of these objects and that Cassini wasn't designed for optical navigation; and it would almost certainly simply miss.

[Galactica55]

Dont land because the other moons of saturn may host life, we just dont know it yet