Jupiter-moon Europa might be covered in ice spikes

[Crush]

Recent news says, that the surface of the Jupiter moon Europa might be covered in sharp ice spikes several meters in height. Do you think that this could cause a problem to future landing missions to Europa? If so, how should they deal with it?

A deadly bed of icy javelins could be awaiting any spacecraft that tries to land on some parts of the ice-covered world Europa, say researchers who have carefully modeled the ice processes at work on parts of the Jovian moon to detect features beyond the current low resolution images.

[...]

Temperature maps of the dark side of Europa have long puzzled scientists because they show a band of unusually cold surface centered on the equator. Penitentes could explain that if they act as cooling fins and speed the cooling of that surface.

Also, radar signals aimed form Earth to Europa and bounced off the surface also show an inexplicable band of poor radar reflection at low latitudes. This could be caused by the baffle-like surfaces of penitentes that are scattering the radar signal, explained Hobley, who is presenting a poster about the work on Oct. 30 at the meeting of the Geological Society of America in Denver.

The new modeling is already a critical factor in the ongoing NASA planning for the exploration of Europa.

"This is a game changer," said planetary scientist Don Blankenship of the University of Texas in Austin. Blankenship has been involved in NASA's planning process for sending a reconnaissance spacecraft and eventually a lander to Europa. Already the new ice models have spurred changes in the instruments being planned for the Europa Clipper mission, hopefully to launch in November 2021, which will do extensive reconnaissance work to prepare the way for a future Europa lander.

Source: http://news.discovery.com/space/is-europa-too-prickly-to-land-on-131028.htm

(yes, it's pop-science so it might not be true after all, but it's cool enough to discuss it under a what-if premise)

[ProjectXMark1]

Hmm, if this is true, like it said, it would be game-changing. You'd need some decent steering on the descent craft, or something to break the spikes (although this is dependent on the thickness of spikes).

[Psycix]

I demand an equivalent in KSP for maximum challenge.

Shishkerbab anyone?

[Sirrobert]

Hmm, if this is true, like it said, it would be game-changing. You'd need some decent steering on the descent craft, or something to break the spikes (although this is dependent on the thickness of spikes).

Ice that's cold enough is stronger than steel IIRC.

So that might be a problem

[SargeRho]

Shishkerbab...we need a moon or planet named like that.

[Idobox]

easy solution: don't land at low latitudes.

harder: melt the thing. A mirror could be used to focus sun light on a spot for a few days/weeks, or the spacecraft could use a laser or microwave antenna to do the same.

Another option would be to send something hot and sturdy to melt the ice before hand, like a ball of plutonium.

Both these solution require precision landing though.

[Crush]

easy solution: don't land at low latitudes.

One long-proposed mission to Europa is an autonomous probe which drills through the ice crust into the hypothetical ocean below it. That would have a much higher success chance at the lower regions where the crust is likely less thick.

harder: melt the thing. A mirror could be used to focus sun light on a spot for a few days/weeks, or the spacecraft could use a laser or microwave antenna to do the same.

Another option would be to send something hot and sturdy to melt the ice before hand, like a ball of plutonium.

You are thinking too complicated: Just drop a bomb! Either shatter or melt the spikes at the landing zone.

Problem: Contamination of the landing zone with residues of the explosive.

[qeveren]

Simple! Just make your lander donut-shaped and go for a ringer!

[Skyler4856]

How hot was the rocket exhaust for the landing stage of Apollo 11?

[Warhorse]

How hot was the rocket exhaust for the landing stage of Apollo 11?

I don't think you'd want to do that, ice that is suddenly heated can shatter rather violently ...

[Skyler4856]

Yeah good point, but we may encounter that anyway (assuming the ground is comprised mostly of ice)

[mdatspace]

How hot was the rocket exhaust for the landing stage of Apollo 11?

A steam explosion would occur, but the droplets of super-heated water would crystallize very quickly due to the frigid temperatures.

[Skyler4856]

Allowing us to save fuel on the decent stage.

[mdatspace]

Allowing us to save fuel on the decent stage.

No. It would blow the thing up. The explosion would fragment it. The ice would turn into steam instantaneously and expand dramatically in volume. That creates a blast which can throw blocks of rock weighing multiple tons hundreds of meters from ground zero.

[7499275]

Here is my idea. Why not just drop a unmanned lander larger then the manned lander with a low thrust (strong enough for soft landing) but it burns very hot. The lander would melt a spot away whilst our manned craft does another orbit. When our craft gets to a burn point to drop on top of the unmanned lander it does so and 1 lands on a safe man made landing location and also has a relativley flat spot to get out and stretch.

[Idobox]

After reading more on the subject, they're not even sure this kind of thing can b created at such low temperatures.

The best solution if it exists is to heat a large zone and let it cool down. That's something we can do from orbit with a good efficiency. Microwaves can be generated with nearly 100% efficiency, and can be focused reasonably well with a large enough antenna.

The other option is to land something to heat locally. Because landing will be so difficult, it needs to be quite sturdy, or not to require structure.

A powder that reacts exothermically with the ice would be the best, if such a thing exist. Another option would be to send two powders that are hypergolic, one after the other. That way, you end up with heat generated over a large surface.

[Motokid600]

Long pointy landing legs that can auto level.

[RedKosmos]

Long pointy landing legs that can auto level.

Pin cushion lander like a bean bag

[Crush]

Why not just drop a unmanned lander larger then the manned lander

Who is talking about a manned lander? We are talking about a robotic lander, maybe a rover.

A manned Mars mission is already a stretch with current technology. A manned Europa mission is still pure science-fiction.

An unmanned Europa lander, on the other hand, is realistic. We already had a robotic lander on Titan, after all (Huygens).

Edited October 30, 2013 by Crush

[Crush]

A powder that reacts exothermically with the ice would be the best, if such a thing exist.

At room temperature, any alcali-metal (lithium, sodium, potassium, rubidium, cesium) reacts violently with water. I don't know if they still do so at below 100 K, though.

Edit: Cesium only reacts with ice at above 157 K, the others only at even higher temperatures. But it would be possible to pre-heat them before spilling them onto the ice.

Someone with more than school-level chemistry knowledge might likely know a better compound, though.

Another option would be to send two powders that are hypergolic, one after the other. That way, you end up with heat generated over a large surface.

Drop a container with thermite, then ignite it with a laser.

Edited October 30, 2013 by Crush

[lajoswinkler]

If it has spikes, I seriously doubt it's ten of them on a square metre, each tall and thick. The only mechanism I see for the "spikes" to occur is the one that happens on comets.

In order to grow actual spikes, you need a saturated vapor environment. Europa doesn't have that and even if it did at one point long time ago, the spikes would've sublimed by now.

Don't worry, there are no monster spikes. Europa might only contain deep cavities in its ice and highly unstable surface.

Imagine this

only every few metres, sometimes covered with loose material so you don't know what's in front of you.

[Motokid600]

I think landing anything on Europa may be dangerous with or without spikes. How.. active is Europa? All that ice floating on a massive ocean. I imagine the ground constantly shifting and breaking appart with earth quakes ( Europa quakes ? ) Same with Io.. but many times more hellish.

Edited October 30, 2013 by Motokid600

[Kerbart]

Nuke it from orbit!

[Warhorse]

I think landing anything on Europa may be dangerous with or without spikes. How.. active is Europa? All that ice floating on a massive ocean. I imagine the ground constantly shifting and breaking appart with earth quakes ( Europa quakes ? ) Same with Io.. but many times more hellish.

Well, the ice is 100 km thick. It's not stable on a scale of millennia the way Earth's surface is, but it's certainly stable enough for anything short of a permanent colony. Scientific estimates typically place the average age of the surface in the range of 20 - 180 million years.

[kiwiak]

Melting landing site or altering it in some other way would decrese sientific value of mission. We want to study europas natural conditions, not what man-made landing site looks like.