This description is pretty bare bones, but with a little legwork, it is possible to flesh out these ideas with some informed speculation. It helps that a number of previous studies have been published that examined concepts for a Europa lander.

The primary goal of any lander would be to sample material from the interior ocean to see if the chemicals needed to support life are present and whether complex organic molecules suggesting biotic or pre-biotic activity exist. We lack the technology to drill through the kilometers of ice to reach the ocean directly. However, in many locations the icy shell appears to be fractured and water from below has spilled onto the surface and frozen, and in certain locations may be actively venting into space. The goal will be to set the lander down in one of these zones.

Our current knowledge of Europa’s surface is too poor to select the scientifically most interesting sites that are also safe to land in. The main spacecraft will spend three years circling Jupiter and flying low over Europa 45 times. One of its prime goals will be to for its cameras and spectrometers to find the optimal combination of evidence of ocean material on the surface with a safe landing zone. Any landing will need to wait for scientists to build their high resolution maps.

One aspect of this proposed lander concept is different than those I’ve seen before. Most lander studies have looked at small spacecraft (and this proposal would count as a small spacecraft) that would be carried by the mother craft until just before landing. For the design Berger reported on, lander and its descent stage would orbit Jupiter on their own for months to years before landing. This means that together they are a fully functional independent spacecraft with its own solar arrays for power, propulsion, navigation, and communications. Apparently the cost and mass of adding these functions to the descent stage and lander is a better bargain than adding the radiation hardening that would be required if the lander were carried past Europa 45 times.

Once on the surface, the lander could be well-protected from radiation. The rotation of Jupiter’s magnetosphere causes the radiation to slam into Europa’s trailing hemisphere. The leading hemisphere has Europa’s bulk as a very effective radiation shield, and radiation there is fairly low. Past proposals have focused on putting a lander on the leading hemisphere. As a result, the lander likely would run out of power before radiation would fry its electronics. Fortunately, there are several regions on the leading hemisphere where the icy shell appears to have been recently (in geologic terms, anyway) fractured.

Berger’s article states that the lander would likely be powered by batteries, limiting its life to around 10 days. Solar panels apparently are being considered, but I can see why they might not be attractive. Sunlight at Jupiter is weak, and solar panels large enough to harvest a meaningful amount of that light might be too bulky and heavy for the mission.

Berger’s article lists just two possible instruments for the lander. Based on his language, the core instrument would be a mass spectrometer that would “weigh” the molecules and atoms in samples scooped, cut, or drilled from the surface. Extremely complex molecules could suggest life, especially if they are rich in elements, like carbon, which are the basis for life on the Earth. A second instrument under consideration would be a Raman spectrometer, which would illuminate samples with lasers and use the resulting “glow” to measure composition including complex organic molecules. (For those who understand Raman spectroscopy, please forgive this simplification of a complex subject; here’s a link to a Wikipedia article for more on this technology.) I’ve also heard through other sources that the lander would carry an imager to examine the terrain around the landing site.

Once on the surface, the lander would use a sample acquisition system to collect a sample of ice from the surface. As Berger points out, at Europa’s surface temperatures, the ice is as hard as rock, so the cutting or drilling mechanism will need to be robust. After the sample is collected, it would be delivered to the instruments to measure its composition. If the lander touches down near an active vent, the mass spectrometer could also measure the composition of the particles and gases in the plume.

Previous studies have typically proposed at least two other instruments. Europa’s icy shell is constantly being stressed by the tides induced by Jupiter, which should produce high seismic activity. A seismometer would give scientists a rich data set on the interior structure of the ice. Europa also sits within Jupiter’s intense magnetosphere, which causes an induced magnetic field in the moon’s interior ocean. How this induced field varies as Europa orbits Jupiter would provide valuable clues to the size and salinity of the ocean. A magnetometer on the lander could provide continuous measurements for the life of the lander. Berger’s article was silent on whether or not these instruments are under consideration for this version of the lander.

(On a side note, a magnetometer plus a simple plasma probe would allow the lander to conduct useful science while it orbits Jupiter waiting for landing. Scientists would like to study Jupiter’s magnetosphere from multiple locations at once. The lander while in orbit around Jupiter could complement similar measurements from the main spacecraft, and depending on the timing, also from Europe’s JUICE spacecraft that will enter Jovian orbit in the late 2020s.)

Berger’s article is silent on how data would be returned to Earth. Two possibilities are obvious – low data rate transmissions directly from the lander to Earth or high data rate transmissions from the lander to the orbiter for later relay to Earth. Data relay from the mother flyby spacecraft likely would be possible, but the rapidly changing relative locations of the landing site and the orbiter circling Jupiter may limit how much data could be returned and when communication relay is possible. A recent European study for a Europa lander assumed that the mother spacecraft would have just one chance to directly receive data from the lander in a 10 day period. One argument for excluding a seismometer is that this instrument would produce large amounts of data that may be difficult to return directly to Earth. The European study found that the brief relay between lander and orbiter would have enabled the return of seismic data. Magnetometers, on the other hand, produce only small amounts of data that likely could be directly relayed to Earth (assuming the lander would have that ability).