Where No Hoover Has Gone Before

Sascha KempfSascha Kempf
Cassini Scientist on Cosmic Dust Analyzer


Cassini’s closest flyby so far of Enceladus is rapidly approaching, and we here at the Max Planck Institute for Nuclear Physics in Heidelberg, Germany, can’t bear the suspense any longer. Our team has built and operates the Cosmic Dust Analyzer, CDA.

CDA is part of Cassini’s suite of magnetospheric  and plasma science, or MAPS instruments, and is capable of determining the mass, speed, composition, and electrostatic charge of typically micron-sized grains, so called dust, striking the detector with speeds of a few tens of kilometes per second (how many miles is that?). Dust particles can tell us a lot about the Saturnian system, because each grain is a messenger and a participant in the physical processes responsible for forming Saturn’s magnificent rings, structuring the planet’s magnetosphere, and reshaping the surfaces of its moons. Like photons, dust particles carry precious information about their site of origin and about their history.

So what does the CDA team want to achieve during this flyby? Enceladus is the major dust producer of the E ring. Most of the particles are emerging from the plumes in the moon’s unusually warm south pole region. Those particles tell us a lot about the conditions inside the surface fractures, where the particles condense from the water vapor ascending through the cracks. There is, however, a second, although less effective way that Enceladus produces fresh dust: fast impacts by either interplanetary meteoroids or by ring particles onto the moon’s surface
produce many new particles—the surface ejecta. We believe that the composition of these ejecta differs from that of the plume particles, and this is one of the main goals of this flyby. If this turns out be true then we can follow the evolution of plume particles through the E ring until their end of life. This knowledge would also help us to understand whether the plumes’ exhaust is deposited on the surface of Enceladus and if so, how much We need just the right geometry to accomplish this goal since we can observe the surface ejecta only when the spacecraft is very close to the Enceladus surface but outside the south pole region.  That’s because the Enceladus plumes are such a strong dust source.

The upcoming encounter is just right for our needs. Around the closest approach, just 25 kilometers (16 miles) from Enceladus’ surface we hope to scoop particles that come directly from the moon’s surface. Later on, when Cassini traverses the dust plumes, we hope to collect genuine plume particles. This approach worked quite well during the last encounter in August.

We can hardly wait!

2 thoughts on “Where No Hoover Has Gone Before”

  1. Where do you think best places the plumes in life? Where would you think the plumes would take us why in the world? Would it tell you that the plume of a moon can not only help the genre of science and technology but change it in a way that’ll tell you that the weight of the world would change because you found a few plumes in the space of the moons atmosphere?
    I can’t seem to find too much about the plume in the space encyclopedia but what it does have it tells you that there really powerful in the non-atmospheric planets. Can plumes change the face of science? I’m not an export but the area really tells you little.

  2. The faster engine exhaust fumes can exit the vehicle the quicker your engine can burn more fuel and air and propel your vehicle fast and more efficiently. This opening up of the exhaust system allows your car to go faster and use less fuel. Cant this trend also be used on the plumes fo the space ships ?

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