NASA Report on Europa Lander

by Paul Gilster on February 13, 2017

With an ocean containing twice as much water as Earth’s oceans, Europa is a high-priority target for astrobiology. But the presence of water alone is not what gives the Jovian moon such interest. After all, we’re learning that icy worlds beyond the snowline can feature oceans beneath the surface, and we’re learning more all the time about oceans all the way into the Kuiper Belt, as the ongoing investigation into what lies beneath Pluto continues.

But Europa, like Enceladus, offers us substantial water in direct contact with a rocky seafloor, and that’s a telling circumstance. What excites astrobiologists is water in the presence of the organic compounds that can become components of biology. The third factor is energy, which Europa has in abundance thanks to the tidal pull of Jupiter, causing flexing of the seafloor that may well be driving hydrothermal activity. Chemical compounds produced from interactions with Jupiter’s magnetic field may also be useful as an energy source.

In June of 2016, NASA’s Planetary Science Division began an early study into a Europa lander. Having a lander here is an exciting thought because study of Europa’s surface shows the periodic breakthrough of oceanic materials that then re-freeze, icy plates that spread apart during this process and so-called ‘chaos’ terrain that may contain frozen material from the interior. A lander here could tell us much about what lies under Europa’s frozen crust.

Screenshot from 2017-02-13 08-27-35

Image: Enhanced-color image mosaic from Galileo showing crosscutting lineae, multiple wide, dark bands where the surface has spread apart (right), and chaos regions (left) where the surface has been disrupted into blocks of material. Image is approximately 200 km wide. Solar illumination is from the upper left. Credit: Figure 1.1 of the SDT report.

The Europa lander work is in its infancy. This is a Science Definition Team report that, as this JPL news release explains, is a routine part of any mission, used to work out the feasibility and scientific value of the concept. The team’s report, involving 21 scientists, was submitted to NASA on February 7. Its goals: To characterize the surface and subsurface of the Jovian moon, supporting future robotic exploration; to assess the habitability of the moon by analyzing its surface; and — the primary goal — to search for evidence of life.

We haven’t developed a full-blown life detection strategy since the days of the Viking landers on Mars, so it’s heartening to see the emergence of a document that makes recommendations on the scientific instruments required and analyzes the systems needed for landing here. We need to get a payload onto the surface without benefit of heat shields or parachutes, given the lack of an atmosphere, and it’s hard to see how this could be done with missions like the current multiple flyby mission scheduled for launch in the 2020s.

That mission is separate from the concept lander now being considered, but it gives food for thought. Flybys, of which the former mission includes at least 45, will be profoundly useful in imaging the moon’s surface at high resolution and investigating its composition. But multiple high-speed flybys make it challenging to slow a lander for safe arrival on the surface. The lander report, therefore, takes a different route, using gravity assists within the Jovian system — at Callisto and Ganymede — to reduce velocity relative to Europa. From the report:

The first Europa gravity assist would mark the beginning of the final mission phase before landing, and the spacecraft would now be exposed to much higher daily radiation doses than before. The first Europa gravity assist would be designed to insert the spacecraft into a Europa-resonant orbit, and ΔV-leveraging maneuvers would further reduce the spacecraft’s velocity relative to Europa (Campagnola and Russell, 2010). This velocity reduction would make the low-energy (or three-body) regime accessible to the spacecraft, in which the gravitational interplay of Europa and Jupiter would enable the carrier to reside in the vicinity of Europa for the full duration of the surface mission. This final part of the tour trajectory, from first Europa flyby to landing, would take approximately one month and would set up the lander delivery to a 5 km periapsis altitude at a target state relative to the landing site.

Screenshot from 2017-02-13 08-36-02

Image: Example tour trajectory showing a Jupiter arrival and transition to Europa. Credit: Figure 10.5 of the SDT report.

After that, we have deorbit and landing, as pictured below.


Image: Deorbit, descent and landing sequence showing the final stages before touchdown on Europa’s surface. Credit: Figure 10.6 from the SDT report.

This is tricky business, using tethers to lower the lander from the descent stage in a ‘sky crane’ configuration before touchdown, with the descent stage impacting at a safe distance from the lander:

Prior to touchdown, the lander stabilizers would be deployed. As the lander is set onto the terrain, the stabilizer legs would contract as needed to both maintain contact with the ground and enable the lander body to remain flat. Contact of the lander body with the surface would trigger release of the bridle. The stabilizers would then be locked in position to yield a stable lander configuration for science operations.

The Europa lander report will be discussed at two upcoming meetings designed to get feedback from the scientific community. The first, on March 19, occurs at the 2017 Lunar and Planetary Science Conference in Texas. The second, on April 23, will take place at the Astrobiology Science Conference (AbSciCon) in Arizona. As early in the game as this is, The Europa Lander Study 2016 Report (JPL D-97667) makes for absorbing reading, and I recommend downloading and reading it on a tablet for convenience.


{ 52 comments… read them below or add one }

Tulse February 13, 2017 at 10:48

Even if Europa is occasionally bringing water up to the surface, given the relatively harsh radiation environment of the Europan surface, what can we reasonably expect to detect as far as potential biosignatures that would survive that environment? How quickly would biological compounds be broken down into simpler, more chemically mundane compounds of more ambiguous origin?

It seems to me that we’re more likely to have success identifying actual biological compounds by sampling fresh plumes, rather than scraping up ice that may be fairly old and been sitting in harsh radiation.


Ashley Baldwin February 15, 2017 at 18:35

Some of the ice isn’t very old. Large areas of Europa show recent resurfacing ( tectonics? Plumes ? ) and even high energy radiation can take up to ten million yet as to destroy organic molecules . Radiation inundation of Europa varies considerable from one locale to another. Sites at higher ( > 60 degrees ) latitude especially on the planet facing side of the moon get considerably lower loads with even just 10cm surface ice ( the minimum proposed excavation depth ) offering significant protection to any organics over millions of years .


Robert Walker March 1, 2017 at 22:54

They plan to drill 5 – 10 cms below the surface of the ice. That’s not much as far as cosmic radiation is concerned, but it’s a lot for the lower energy Jovian radiation. So – if the ice has come to the surface recently and the ice is not accumulating at significant rates, then it could be reasonably undamaged.

I think the main issue here is that it is going to be mixed with organics from comets and meteorites and also with organics manufactured on the Europan surface itself by various processes which make long chain organics from methane, carbon dioxide, water etc, to make the so called “tholins”. How can they tell it apart from life based organics? The amount of life also may be very low if it is there. If it is viable you could tell by providing an environment in which it could metabolize – say by a chiral labeled release, then even if there are only a few viable cells mixed in with the organics, they would still metabolize and you’d detect them (doesn’t require them to reproduce). But they probably won’t send any metabolism testing experiments. And the chance of life in such a tiny set of samples on a random area of Europa selected from photos with a maximum of half a meter resolution seems low.

While as you say if sampled from a plume, especially if there is good evidence it comes from the subsurface ocean, there’s much less chance of it being mixed up with other things. Still depends how much life there is in the ocean. It may have a lot of abiotic organics too. And the number of cells could be very low, or localized to the hydrothermal vents and not get into the geysers. But at least you are testing material that’s come from one of the places most likely to have life, you are giving your experiment probably its best chance of success.

I cover this and other issues in my “OK to Touch Mars?” which I’m continuing to work on, in
Would a Europa lander be likely to spot life?

Strengths and weaknesses of the "lego principle" approach

How diagnostic is the carbon 12 to carbon 13 ratio?

Mixtures with other organics from comets, meteorites, and produced locally on Europa – and degraded organics Abiotic organics that mimic biosignatures
Degraded organics from life



Jim Early February 13, 2017 at 12:30

Without seeing the report, knowing NASA I would bet they propose using the wrong launch vehicle. The mission would need a Delta IV Heavy (28MT to LEO) or an Atlas V-552 (20 MT LEO). By the time the mission could fly, the Delta will certainly be cancelled because of costs, and the Atlas series may be in trouble. The logical vehicle would be the Falcon 9 F.T. (23 MT LEO) or the Falcon 9 Heavy (54 MT LEO) which have half the costs of the Atlas or Delta vehicles and also have heavier payloads. Since the Falcon 9 Heavy has an underpowered second stage, by the time for the mission SpaceX will probably have a much heavier second stage using the Raptor engine. This configuration should be capable of 75MT in LEO at half the cost of a Delta IV Heavy.
The use of a SpaceX launch vehicle will probably both lower the mission launch costs and allow a heavier spacecraft.


Alex Tolley February 13, 2017 at 13:04

I would bet money that Nasa would opt for using the SLS to justify its continuing development.


Enzo February 13, 2017 at 18:38

I believe that a lot of pending missions were told to wait for the shuttle that would have been so cheap……
Galileo suffered a lot because of it.
Planning to use not yet existing and reliable launchers is a recipe for disaster.


Jim Early February 15, 2017 at 10:00

Bingo, you hit the target with your first shot! The Europa Orbiter mission was cancelled in favor of the lighter Europa Multiple Flyby Mission which uses an Atlas V 551 and a 6 year trajectory including a Venus swingby. The Europa Lander has a mass of 250 kg with 30 kg of instruments and appears to be sized for a separate Atlas V launcher. NASA now plans to combine the two payloads on a SPS 1B. This would be only the second SPS launch and would be the first launch with an upgraded second stage. The excess payload capacity would be used for a faster, three year trajectory. It is noteworthy that they are holding the Europa payloads to masses that can still be launched on slow trajectories by separate Atlas V’s.


Ashley Baldwin February 15, 2017 at 16:58

That SLS is cited in the report. As far as the Falcon Heavy goes I like everyone else have high hopes for it and wish it nothing but good luck. The hard fact is that it hasn’t even flown yet , with no official date even set for launch other than Q2/3 this year and a couple of teaser SpaceX publicity shots


Sky February 14, 2017 at 12:46

Don’t use LEO figures. What matters is what it can deliver into hyperbolic orbit. Falcon 9 is loosing performance much more quickly than rockets with LOX+LH2 upper stages.


Jim Early February 15, 2017 at 10:02

I agree. I just could not find escape performance figures for the Falcon rockets. I used LEO values as a poor substitute.


Ashley Baldwin February 15, 2017 at 19:02

There are no plans for a FH raptor powered second stage . The Raptor has about 3 X the thrust of the current falcon second stage Merlin-D engine so any new stage would need to be strengthening structurally if not redesigning totally . Although similar in size the Raptor is also bigger than the Merlin-D engine ,so it’s far from a question of squeezing in a Raptor as an upgrade . A costly and time consuming project .Even then the high accelerations produced would potentially damage any payload ( including astronauts ) .

The whole SpaceX policy on cost reduction is centred on minimising the various launcher ( and engine AND fuel ) iterations in order to keep maintenance costs down ( akin to budget airlines) . The Air Force have to be fair helped co fund development of a vacuum second stage Raptor engine, but NOT a second stage itself. Presumably to give it a choice of engines (along with the Blue origin BE-4) for its own heavy lift “national security “purposes .

The Falcon Heavy will be built around the final Merlin-D Falcon 9 block 5 cores with perhaps a 5-10% improvement in performance on that currently posited . ( still impressive mind if 60 tonnes to LEO, 25 to GTO and 16 to Mars. Might even support a manned lunar mission ! ) There is also no logical reason to build for instance an all raptor powered ultra heavy launcher for the commercial use ( as SpaceX initially proposed with its now abandoned FalconX and XX concepts) which SpaceX so desperately need to reduce their dependency on NASA . There is simply no market other than occasional deep space missions that NASA might throw their way and that would do just as well with a conventional FH supplemented with perhaps the ever dependable Centaur third stage.

The Raptor using ITS is a one off if ever built and is bespoke for Musk’s dream of Martian colonisation.


Jim Early February 13, 2017 at 12:42

Does NASA have a more preliminary analysis of a similar mission to Enceladus that one could use for comparison? The combination of a Jupiter fly-by and the lower delta V for landing on Enceladus would likely result in a similar total mission delta V. Enceladus would offer easier access to recent ocean water and a lower radiation environment at the expense of a longer transit time.


charlie February 13, 2017 at 12:50


Landing on our own moon is so 1969. Scientists are now looking for new moons to explore. And in the running is Jupiter’s icy moon Europa, which may just be the next big point of curiosity for our space agency. Earlier this week, NASA announced initial findings from a “report on the potential science value of a lander on the surface [Europa],” and further noted that “the agency is now engaging the broader science community to open a discussion about its findings.”

Last year, NASA asked 21 scientists to conceptualize a lander whose destination would be Europa, and also determine whether such a mission would be feasible and what scientific gains might be achieved. It was a tall order, but just eight months later, the group handed over its report to the space agency.

More: NASA is close to making computers that can survive on Venus

“The primary goal is to search for evidence of life on Europa,” NASA notes of the new report. “The other goals are to assess the habitability of Europa by directly analyzing material from the surface, and to characterize the surface and subsurface to support future robotic exploration of Europa and its ocean.” As per their research, the scientists have reason to believe that Europa may have a global saltwater ocean, and that at the bottom of the ocean is a rocky, silicate floor, which could indeed contain the ingredients needed to sustain life.

There are plans for a solar-powered Europa multiple flyby mission, currently slated for launch in the early 2020’s. NASA says that this spacecraft (which is different from the new lander designed by the team of 21 scientists), “will arrive at Jupiter after a multi-year journey, orbiting the gas giant every two weeks for a series of 45 close flybys of Europa.” This mission will seek to determine Europa’s habitability, and also set the foundation for an actual landing.


Alex Tolley February 13, 2017 at 13:15

So the multiple flybys mission’s success is crucial to get the high-resolution images of Europa’s surface to plan for the lander mission. I look forward to reading the 2016 report to understand how they will go about detecting life and the assumption behind the instruments to be deployed.

Paul, I hope you will be able to post on the various meetings discussing this project, either yourself or with guest authors.


Paul Gilster February 13, 2017 at 22:15

Will do my best, Alex! Unfortunately, I can’t be there in person at either of the upcoming ones, though.


Ashley Baldwin February 15, 2017 at 17:39

The assumption is made that there have already been sites identified ( by the best Galileo imaging of < 1 % of the surface) . These sites seem to indicate upwelling of subsurface organic material , possibly from an underground ocean , in several areas of the moon. In terms of radiation , there is a considerable variation from one area of the moon to the other further complicated by the time radiation would take to destroy any organic molecules . Up to ten million years in the most favourable spots . Some areas of Europa seem to have been resurfaced well within this timescale too which helps and in the least radiation exposed sites ( above 60 degree latitude on the Jupiter facing side of the tidally locked moon) the damage it causes is unlikely to have penetrated below 10cm of the icy surface, the minimum depth proposed for the scoop sample arm. Rather than an energy expensive and heat producing drill the lander proposal posits a saw toothed scoop on a Viking/Phoenix like extensible arm . Indeed the whole concept is based around adapting previous mission heritage (mostly Mars rovers and landers) technology with the basic sub structure akin to Phoenix. Missions like Rosetta , Dawn ,Insight ( once it's all important and readily transferable seismometer is sorted out ) ,MSL, Mars 2020 and indeed the Europa flyby itself have provided a wide array of readily proven and available payload instruments not least the important high resolution Raman spectrometer . Some with cheap flight spares too. There is even a facility to add miniature electron microscopes . Not absolutely cutting edge , but crucially proven and economic whilst still highly sensitive .

In addition to the EMFBM the lander's Carrier Relay Orbiter , CRO, can carry out site reconnaissance too with all the info available used to produce Surface Terrain Maps , STMs with horizontal and vertical resolution of <50 cm/pixel and which have been pioneered and fine tuned for Mars landing sites already . They can be fed into the lander's flight computer to allow flexibility in its landing site ellipse

Having read the report it reads almost like a high tech "scrap yard " challenge with literally everything , even down to the skycrane landing system having High heritage apart from the lidar based hazard detection and avoidance system for landing . Even this has has been perfected without actual use yet by both Nasa and the ESA. It's mature enough to be available for a prospective New Frontiers 4 mission as a freeby though. All apart from the SLS though even here savings can be made by using it more often and reduced operations from a quicker transit time to Jupiter. This is an excellent first draft and a very serious effort to keep costs to a minimum with a minimalist "threshold" strawman payload option and uprated "baseline" option by way of comparison too. This is certainly no aspirational $6 billion JPL scheme with no recourse to outlay.

This report is one of the most realistic and practical mission concepts I've ever seen with every effort made to reduce cost . It is certainly written by people who have submitted cost conscious bids before . No MMRTG for power presumably given a perceived environmental hazard ( and a $ 100 million price tag ) if they melted through the ice to any ocean below and any solar panels would get fried and take up stair age space enroute , so battery power only . Good batteries though . The plan is for a baseline mission of 20 days ( but hopefully longer ) which still allows a lot of science data which can be readily uplinked to the CRO for the ten hours it is above the horizon "per day ". ( with a possible backup mentioned of using the EMFBM craft if it is still operational during landing ) Ironically a short mission also helps reduce costs given its short operations time .


Alex Tolley February 15, 2017 at 23:37

There is even a facility to add miniature electron microscopes . Not absolutely cutting edge , but crucially proven and economic whilst still highly sensitive .

Very interesting. Do you by chance have any references for the electron microscope, especially with regard to design and specs?


David H February 13, 2017 at 13:39

This is super cool and I’m much more excited about this than I am about sending yet another thing to Mars. The deceleration/landing plan is very impressive and well-conceived, but what I really want to know is what sort of instrumentation the lander would have. I would think that at minimum, it should sample, melt and analyze some of the ice. It should also have a sensitive seismometer. I have a feeling Europa’s ice crust creaks from all those tidal forces, and the analysis might teach us about its thickness.


Alex Tolley February 13, 2017 at 14:10

More evidence that Earth life might survive to colonize other worlds? Polar Algae Survive Two Years in Space. If we can determine the environmental conditions of the sub-surface oceans of icy moons, it would be interesting to try to culture such organisms in those conditions as a gauge on the possibility life colonizing such worlds, even if their genesis is elsewhere.


Dmitri February 14, 2017 at 7:41

Alex, a bit off topic question but important for me – how did you manage to link the URL into text? I’ve struggled with it years here. Have not found any reasonable solution. Trying to seize the opportunity.


Paul Gilster February 14, 2017 at 10:00

Yes, off-topic, but I’ll let this stand because so many people have had the same question! So Alex, by all means, explain the link insertion method for all to see.


Alex Tolley February 14, 2017 at 13:54

Use an html link like this:

<a href=”Link URL”&gt text for link </a &gt


<a href=””&gt Centauri Dreams </a &gt


Alex Tolley February 14, 2017 at 14:01

Escape characters are not working the same on Wordpress and html so an image instead (ironically needing the html link):

image of html link


Douglas Dwyer February 13, 2017 at 14:20

Straying from my FRB comfort zone but:
This could be a practical test for a group of solar sail probes prior to the star shot. Multiple low power image versions could be transmitted ,the more received the better signal to noise.


spaceman February 13, 2017 at 14:33

A mission to search for life on Europa is one of the most important scientific investigations of all time. Think about the stakes: if no trace of life is found despite billions years for water, organics, and a probable source of energy to interact, then this would imply that abiogenesis is a fluke. On the other hand, if we find that life arose on Europa independently, then we can be sure that the Universe is teeming with at least primitive, single-celled life. We may know in the next few decades whether or not De Duve or Monod was correct–that is, is the origin of life a “cosmic imperative” or is the origin of life a fluke event that arises perhaps only once or twice per million or more galaxies?


jonW February 13, 2017 at 20:56

There’s a pretty big range between a cosmic imperative–let’s say 1 in 100 systems, so roughly a billion life-bearing planets in our galaxy alone–and “a fluke that arises once or twice per million galaxies”! No reason to believe the truth has to lie at one extreme or another of this range of probabilities, rather than somewhere in the trillion-fold middle between them, whatever the results from Europa once we get there!


Harold Shaw February 14, 2017 at 17:11

Advocating a measured response to minimal evidence or measured expectations….clearly you are not from this planet.

As amazing as it would be to discover an ecosystem of complex life on Europa, I would rather us discover a prebiotic or transitional ecosystem. I think a lipid/rna/protien world ecosystem would teach us more about abiogenesis.


Ashley Baldwin February 15, 2017 at 18:16

I agree that sterilising the lander to prevent any contamination is entirely feasible. Another interesting option would be if there are signs of life identified but which are Earth like. We know there have been some hefty asteroid “splashes ” on Earth during life’s long tenure , and that there has been cross contamination between Earth and Mars . So with Jupiter’s far larger gravity well it’s not entirely inconceivable that some of the resultant Terran meteors may have impacted “in the firing line” Europa subsequently .


FrankH February 13, 2017 at 16:21

@ Jim Early – I agree, Falcon 9 is the way to go. It’s possible that the launch vehicles listed are just boilerplate, with the real launcher TBD (after maybe a few successful Falcon 9 Heavy missions to say, Mars.

Also, why just a fixed lander? With current technology (and a better launcher) some basic roving ability shouldn’t be that much more expensive. How frustrating would it be to see a potentially interesting spot just out of reach of the lander?

Finally, the Delta V requirements just to move between the moons of Jupiter is pretty impressive:


Sky February 14, 2017 at 12:49

There’s no compelling reason to use an inferior Falcon 9. Price difference is tiny in an overall costs of the mission, meaningless in fact.


Michael February 14, 2017 at 17:40

Using low energy pathways should reduce the energy required quite a bit. I would love to see a magsail attached which could use Jupiter’s powerful magnetic field as a power source and orbital changer.


Ashley Baldwin February 15, 2017 at 18:05

I think it would be great if the FH comes through and if it does will offer enormous and economic opportunities for quick transfer deep space missions ( with a suitable upper stage ) . It’s site even mischievously claims a 2.9 tonne payload to Pluto. However until it has flown safely on numerous occasions I think we should exclude its deep space use for the foreseeable future .

SpaceX’s immediate priorities also currently lie with sorting out troublesome Composite over wrapped pressure vessels , fuelling procedures and turbine cracks so as to deliver reusability before getting its Dragon capsule man rated and to the ISS safely. Even if it can do all that by 2019, that’s too late for participation in setting off , twice, to Europa in the early to mid 2020s as we all hope .


Ashley Baldwin February 15, 2017 at 18:08

The lander plan emphasises the aim of identifying opportunities for future rovers . Landing on Europa is a serious technological challenge and if it can be done by the middle of next decade I think that is no mean technological , and political achievement .


Geoffrey Hillend February 13, 2017 at 19:44

I agree with Alex Tolley. It’s a good idea to have a Europa orbiter to make some high resolution images for a good landing spot like NASA did with Mars which would be the cheaper way to go than multiple flybys. What happens in an unmapped area where there are cliffs or large boulders everywhere so that the landing vehicle has no safe spot to land which would be a possible catastrophic failure of the lander and instruments if they get damaged.


Ashley Baldwin February 15, 2017 at 17:55

There is an intention to create Surface Terrain Maps , STMs utilising the Europa Multiflyby craft and probably the lander carrier really orbiter too . This technique has already been perfected for Mars landing sites . It doesn’t have to cover the whole surface , just the least radiation drenched areas that can be landed on according to orbital mechanics ,and can be targeted from various angles to create the stereo STMs required for a safe landing with low risk and high precision . Small areas of Europa where covered by Galileo in relatively high precision and have already turned up some very promising sites that can safe time and effort and be targeted. They all lie at greater than 60 degrees latitude on the planet facing side in the lowest radiation exposed areas . NASA also have their new lidar based hazard detection and avoidance system that is already proven to a high TRL and is already available for use on New Frontiers 4 . It can be used in conjunction with a further upgraded skycrane landing system post its use for Mars 2020.


Alex Tolley February 13, 2017 at 23:38

The report has a very good section on the approach to look for life, both extant and fossil. Multiple lines of approach are used which is very encouraging. They also have fall back science goals is no sign of life is discovered.

I’m happy to see they are including a microscope too. While such scopes are quite heavy (the full science payload is just 45 Kg) they do note:

NASA’s in situ search for life in our solar system would benefit from increased investments in advancing miniaturized microscope technologies for robotic spaceflight missions, specifically targeting evidence of life.

I’ve seen some interesting new ideas in this direction which I hope can be exploited in the Europan environment.

It looks like an exciting mission. I hope the non-life science objectives are good too, as I am not sanguine that the life experiments will find anything. But if they do, then WOW!


Robert Walker February 14, 2017 at 8:36

My main issue with the Europa lander is that

* NASA are mandated to launch it to Europa before the orbiter gets there. How can we know what to send to Europa when we don’t yet have close up information about it? For instance is its surface rough and covered in penitentes? Does it have thin ice over liquid water from ascending plumes from the Europa ocean about to break through its surface? Does it have geysers like Enceladus? All those things we may find out with the orbiter mission.

* We don’t know what level of sterilization is needed. If the lander could potentially impact into ice that later on contacts water on Europa in a plume or geyser with connection to the Europa ocean – we probably are not yet able to sterilize a lander sufficiently at all to keep Europa free of Earth life.

After all, Galileo was redirected to impact into Jupiter itself to avoid the tiny risk of contaminating Europa. How then can it be okay to land a mission on Europa which could potentially crash on the surface? I’m not sure we can sterilize to that level. We may be able to achieve 100% sterilization. It’s not impossible, e.g. heat resistant electronics such as are used for ICBMs that can be heated far above the usual maximum temperatures for a spacecraft. But if so it would add to the expense and would need new technology not yet flown in space.

Also – if Europa does have recurring geysers as is beginning to seem quite likely with Hubble’s repeat observation of a water vapour – then surely the best mission is to sample the geyser? Especially if it comes from the subsurface ocean or from a rising plume of liquid water from its ocean.

It would be the freshest possible sample we could have of its ocean, and it would have almost zero planetary protection issues. They could use a similar approach to the lander, but use it to get an orbiter into a temporary orbit around Europa, distant retrograde orbit, with very low relative velocity, then dip low to sample the geysers.

Again this is a mission that should probably be launched after the multiple flyby mission gets to Europa. Though we could do preliminary design before then and have the components space flight hardened, almost ready to go but give the possibility of last minute changes.

It need not take long for a mission to get to Europa – especially by then with the advances of technology we’ll have by then.

They plan to send the mission to Europa possibly as soon as 2022 to get there by 2025

So then the follow up mission to sample the plumes could set off in 2026, get there by 2029. Or it could get there faster if we have more powerful rockets by then. The fast Hohmann transfer time is only two years to Europa.

Then some time in the early 2030s, send a lander to Europa. By then we know the surface conditions very well, and if we make it a priority, then that’s enough time to find a way to sterilize the lander 100% – and perhaps make it a rover too. Some time later we send a 100% sterile submarine too.

What we have on Europa could be very vulnerable to Earth life. One example, what if there is some early form of life, RNA world, or even earlier that has been made extinct by Earth life long ago on Earth. That would be one of the most interesting things we could find there. Just a few Earth microbes that somehow get into its ocean could mean that a few years later there is not a single microbe left of the Europan life that was in its ocean before the first visit. That would be tragic. And if it doesn’t happen that quickly, it might yet be inevitable that it happens eventually. We have to be sure to explore in a responsible biologically reversible way.

See my “Searching for life on Europa and Enceladus”


Jim Early February 15, 2017 at 10:46

Your timing concerns would be for the original proposal to have separate launches on Atlas V’s. I believe the new NASA proposal is to launch both spacecraft on the same SPS 1B and to fly a faster three year trajectory. The design appears to keep the Atlas V payload masses in case the SPS 1B is not available in time.


Robert Walker February 17, 2017 at 16:27

Oh the latest I heard is that because of concerns that NASA wouldn’t be able to get it done by 2022 they split it into two missions. First to send the orbiter in 2022. Second to send the lander to launch in 2o24. I get this from the Two SLS to Jupiter in the Space Review.

This new report is based on that same idea, see page viii of the executive summary:
” These design requirements include the following: the lander would
be launched by a Space Launch System (SLS) rocket separately from the
EMFM [Europa Multiple Flyby Mission] and would include a Carrier
Relay Orbiter (CRO) spacecraft to support data relay to and from the Europa Lander; the EMFM would only serve as a back-up telecommunications link. ”

From the Space Review article, then part of the motivation for this is that Launch on an SLS would permit a larger orbiter, more science instruments, more radiation shielding and get there sooner. Separating it into two missions means you have two SLS missions instead of 1 so helping with their problem of how to achieve an SLS mission at least once a year.

Then from the Space Review, they want to launch the lander in 2024 for the political reason that launching it soon after the first orbiter helps them to have more SLS launches more quickly, even though scientifically you’d want to wait for the results of the orbiter before launching the lander, surely. The whole thing is driven by politics. The idea of sending an orbiter to study the geysers is not considered at all, because Congress has mandated a lander. And the reason for delaying by 2 years is for political reasons, while scientists surely if they had a delay would delay it until at least after the multiple flyby mission gets there, in order to give them a chance to make changes if necessary based on what new data about Europa turns up.


RobFlores February 14, 2017 at 12:53

It looks like there will be no 3D detailed surface survey to select a safe
landing site, the risk maybe similar to the Viking Landing. We had
2 Viking Landers. For one of the Vikings there certainly was the near by possibility of severe damage as post landing analysis showed.

Since, we will only have one lander for Europa, maybe a bit cheating is in order. I would propose for Europa mission that we send the lander with an additional 3-4 sub units of a dozen or so pounds each. (I know that a surface radar would be part of the mission, but said radar may not give clear detail)
These units would attempt to land in Europa ahead of the main lander, any successful landings, would result in minimal telemetry being relayed to main lander that it arrived intact and issue a homing beacon. The Main lander can then select the best site according to it’s own AI. The sub units admittedly would only be a few minutes ahead of the Lander. Now I am sure that due to limitations on fuel the main lander can only alter it’s final target landing spot minimally, perhaps a mile or two. So the sub units would have to follow that restriction when being scattered to land.
If you loose all the sub units, and no telemetry is received then what could the descending probe do? Hope it’s AI is up to the task of a difficult landing.


Michael February 14, 2017 at 17:34

Might be a good idea to strap these sub units onto the orbit insertion rocket unit and they are ejected just before it hits the ground. If they are built smartly they could be used to give high resolution data about the surroundings for possible landing sites. It is a pity we could not have a high powered laser system attached to the orbiter that could beam power to the units on the ground saving a lot of weight.

Just finished reading 264 or so pages of one of the links, quite a read!


Robert Walker February 14, 2017 at 20:10

Oh okay thanks. I’ll do that in future. I don’t think I can edit my previous reply.
“Searching for life on Europa and Enceladus”

I’m working on the book at the moment and have added a section with my take on the new planetary protection guidelines in this new report which may interest some of you – I use an analogy of a Ming vase
Published planetary protection guidelines for the Europa lander

Also – sorry in previous comment I mentioned ICBMs for high temperature electronics, but I was forgetting – when I wrote that section, that was my starting point for the search, but though there are military applications, it’s actually mainly driven by oil rig deep drilling, improvements in aircraft, and automobile improvements, especially for electric vehicles, where it helps to have high temperature electronics close to engines and other hot components. I haven’t been able to find out much about high temperature ICBM electronics actually. Anyway I have expanded the part about high temperature electronics: Can we achieve 100% sterile electronics for a Europa or Mars lander?. I also added new material about designs for Venus landers / rovers which would have used high temperatures 200 C to 300 C electronics and other components able to withstand those temperatures.

I think a 100% sterile Europa Lander is definitely feasible. Because anything that can withstand such high temperatures could be 100% sterilized of Earth life. And you could sterilize it in orbit if necessary at those high temperatures or in transit to Europa if it could withstand them as well as a Venus lander.


Charlie February 16, 2017 at 2:17

While this is a extremely fascinating concept as to how to approach landing on this Jovian moon, I’m particularly bothered by some of the comments that have been made here concerning gravity assists as a means to obtain accurate mapping of potential landing sites for the probe as it slows down in the Jovian system.
To whit, these photographic assays are going to be done literally on the fly as the probe gets ready to go into a landing approach pattern on the destination moon. Question arises in my mind is how accurate can we expect this photographic montage to be if you’re doing it while speeding overhead ?
Classically you approach the problem by putting a orbiter around the body you wish to study and then over a period of time gradually developed a picture of potential will landing sites with high resolution and in particular time to make a detailed assessment of the pitfalls and advantages of where you’re planning to go.
This appears to be a sophisticated but nonetheless mirror image of a pinball maneuver far the craft to bounce around between moons until it finally gets to the proper speed. Pinball is fine if you’re playing a game, but if you’re going to land a billion-dollar probe you might want to rethink the proposition. That’s my only criticism of this as a potential approach to getting a scientific return on a costly Lander. I’m sure that there is going to be many who disagree with this simply because of the fact that they believe that something that is unique and new is necessarily better when it may in fact be a replay of the same old mantra – cheaper, faster, better.
That mantra was done on several of the Mars probes and they ended up in the junk pile and crash and burn on the planet, or within its atmosphere. Do we want to really have a replay of this lurid, but siren call ? I thought we had gone to the point where caution was the watchword rather than something that has a lot of flash to it.
On extremely positive side, though if this Lander possesses a high degree of sophisticated and a powerful artificial intelligence and if it coupled with a robust sensory system to detect abrupt topological changes as a descendent then it might be a gamble that would be worth taking.
A lot of other people made some very perceptive comments regarding the mobility of the probe and its ability to look for interesting signs of life by being mobile. That’s certainly something that might be worth considering.

Also too. I’m wondering about whether or not this probe can be sufficiently sterilized and ridded organic contaminants such that it won’t compromise the mission.

Paul, do you happen to know who was the originator and calculator of this very clever and sophisticated set of gravity assist maneuvers that have been proposed for this type of mission ? In other words, what organization (s) actually did the mission analysis ?


Robert Walker February 17, 2017 at 16:35

Charlie, this sort of gravity assist is very different from the Mars situation. The problem with those Mars probes is that they have a one off opportunity and their engines have to fire, and then stop, on cue ,never having been used before and with no feedback from Earth until the operation is over. It’s the same for the maneuver to achieve capture of Jupiter or Saturn.

But once they are in orbit around the destination planet, then the maneuvers are very controlled because they have days, weeks, in which to do the corrections, and they can then check that they were done correctly and that it is on the right orbit. This has proven to be very reliable. Goes back to Voyager. Similarly, Dawn at Ceres, Rosetta at comet 67p, New Horizons at Pluto. And most similar of all the Cassini mission which has done many course changes in the Saturn system achieving very close flybys for instance of Enceladus, flying close enough to directly sample its plumes. So far none of those course corrections has lead to a crash or anything untoward at all AFAIK. The main issue is that it might run out of fuel, or the rockets fail if they are kept dormant for a long time then revived.


Strati February 19, 2017 at 2:03

Question about a potential follow-on to this, knowing that mass budget for any outer solar system mission, much less a lander, is tight.

What would the requirements be for a penetrator mission be? Ideally you’d want a heated body coming in at as high a velocity as you could to maximize depth (to get down to the liquid layer you’d have to have internal heat as well, and that’s probably the only way this would make sense as a mission). If you have a lander with some sort of seismograph on board, you should be able to use some variant of sonar for communication, right?

The plumes and detritus from them are the easy target (if you can call anything that far out easy), but if you’re going to develop a life-detection suite of instruments, why not try for the full enchilada and at least look at what’s required to get down to the part that we’re really interested in?


ljk March 1, 2017 at 22:20

In the search for life on Mars, are robots nearing their limits?

Curiosity and the upcoming Mars 2020 rover will continue the search for indirect signs of microbial life on Mars, but some scientists suggest it might take a human touch to uncover conclusive evidence.

By Charlie Wood

MARCH 1, 2017 —Is there – or was there ever – life on Mars? NASA has spent decades investigating the question with orbiters and rovers, including its upcoming Mars 2020 rover, but at least one scientist suspects he already knows the answer.

According to Gibert Levin, NASA probably detected microbial life on Mars in 1976.

Dr. Levin was one of the scientists involved with the Viking lander, whose biological experiments gave conflicting results when samples tested positive for metabolism but negative for organic molecules. Scientists at the time agreed that what looked like biological signs must have resulted instead from natural processes, but after decades of follow-up research recreating the Martian experiments in hostile landscapes such as Antarctica and the Atacama Desert, combined with a better understanding of Mars as well as the durability of life on Earth, Levin has a different hypothesis:

The unreliable organic molecule experiment was the one that failed, and the metabolism detection succeeded.

The continued debate surrounding the interpretation of a four-decade-old experiment highlights the challenges of looking for life, or its fossilized remains, with indirect experiments conducted by robots a world away.

Full article here:

To quote:

“We’re not looking for skeletons. We’re looking for fossil microbes — if [Mars] life did indeed go extinct,” said Ellen Stofan, then NASA’s chief scientist, at a conference last year. “And those are going to be hard to find.”

NASA rovers Sojourner, Spirit, Opportunity, and Curiosity have made astounding discoveries in their combined 27 years of Martian exploration, including signs of an ancient ocean, flowing water, as well as the active organic molecules that eluded Viking, but while the machines have significantly expanded experts’ understanding of Mars as a warmer, wetter world that once had the conditions for life, we are arguably no closer to finding smoking-gun evidence of microbes than Viking was in the mid-1970s.

Dr. Stofan suggested conclusive proof may have to wait until someone can get actual humans, with their superior programming and higher bandwidth, out to investigate in person.

“I strongly believe we will never settle this question of determining whether or not there’s life on Mars unless we get human scientists down onto the surface of the Red Planet,” she said.


ljk March 1, 2017 at 23:27

Humans may still be needed in detailed science exploration of the other worlds, but that does not mean they are going to be out there anytime soon unless something radical happens:


ljk March 6, 2017 at 12:20

Landing on alien worlds is our highest form of exploration

Chris McKay is a senior astrobiologist at NASA Ames Research Center. His research focuses on the evolution of the solar system and the origin of life.

The expression ‘We’ve landed!’ connects to something deep and instinctive in the human psyche. Those words mean that we have crossed an inhospitable expanse and staked our place on the other side. At first, the expression referred only to voyages across the ocean, then also across the sky, and now across space as well. Through all those leaps, the essential elements have remained the same: a specially built craft, a long and daunting journey, a burst of fresh danger on arrival – and a pause to celebrate merely surviving. Then comes the magical moment when we look up and cast our eyes over an unfamiliar horizon. We become a species of explorers all over again.

Forty-seven years after the fact, Neil Armstrong’s message ‘Houston… the Eagle has landed’ remains one of the defining moments of the space age. Landings don’t even have to involve humans to be emotionally stirring. A robotic landing was what first drew me into planetary science and astrobiology.

In 1976, while I was starting my first year of graduate school, the twin Viking probes touched down on Mars. They inspired me, far more than the earlier Mariner spacecraft that had flown past or orbited the planet. The images were both tangible and shocking: a salmon-coloured sky hanging over a rusty desert, its rocks scoured by thin, persistent winds. We were on the surface of Mars! My general interest in astronomy quickly narrowed into a specific fascination with Mars that persists to this day.

Despite their emotional power, space landings are few and far between. There are good, practical reasons for that. Landings are complex and expensive. Flybys and even orbiters are cheaper, easier and in many ways more sensible from a pure-science point of view. But NASA and the other space agencies are missing a huge opportunity here to make space exploration more evocative, and more personal. There simply is no other space vista that compares with seeing an alien horizon, capturing the perspective of an astronaut standing on another world.

Full article here:

To quote:

There is an important lesson from these experiences: space missions to other worlds are not just about the science. They are about the human instinct to explore. The fascination with landing is part of that instinct. Even if the science is best served by merely orbiting or flying by, we should land whenever we can. They don’t have to be conflicting choices; often they can (and have been) done together. As for where we should land, the options are staggering. It’s been three decades since the last Venus landing; humans have only ever landed on one moon other than our own. There are many, many vistas waiting for us.

Jupiter’s large, ice-covered moon Europa is the next major target for a landing, but there has been a reluctance to commit. NASA scientists worry that the challenge is too hard, and that we have not surveyed Europa’s surface enough to find the ideal, safe landing site. Yes, there would be risks in landing there. Europa has no atmosphere in which to use parachutes. Then again, its surface gravity is similar to that of Earth’s moon, so we could use some of the technologies already developed for landing earlier robotic Moon landings. The risks of landing are similar to those of putting Pathfinder on Mars and Philae on the comet. The risks of not trying to land on Europa are more severe: we could lose the momentum for exploring this fascinating moon and searching for life in the global ocean beneath its frozen surface.

A Europa lander could be the beginning of a whole new era of space exploration. Landers don’t all have to be complex, costly machines like Curiosity. A stationary, battery-powered robot on Europa could still last long enough to survey an alien horizon unlike any seen before – our first view from the surface of an ice world. It could inspire follow-up missions to put eyes on the ground all across the solar system, so people hear the words ‘We’ve landed’ more often. There will be a rich scientific payoff but, even better, it would allow people around the world to experience other worlds from a distinctly human perspective.


ljk March 16, 2017 at 18:47

We didn’t need the Monolith ETI from the 2001 franchise to keep humanity from landing on Europa, at least this time:


ljk March 20, 2017 at 10:50

Meet the Puffers: NASA reveals palm-sized popup planetary rovers that could explore lava tubes on Mars and look for alien life on Europa

Pop-Up Flat Folding Explorer Robots, or Puffers, have a collapsible design

They’re small enough to be carried on another craft, such as a Mars rover

Then, when a rover spots area of interest, it can deploy one or more Puffers

NASA says they could explore lava tubes on Mars, or ‘chaos terrains’ of Europa

By Cheyenne Macdonald For

PUBLISHED: 18:51 EDT, 14 March 2017 | UPDATED: 19:18 EDT, 14 March 2017

NASA researchers are developing origami-inspired robots that could soon be used to explore extreme alien environments.

The Pop-Up Flat Folding Explorer Robots, or Puffers, have a collapsible design and are small enough to hitch a ride on another craft, such as a Mars rover or Europa lander.

According to the space agency, these adorable robots will be able to reach areas that the larger vehicles cannot, allowing them to investigate caves and lava tubes on Mars, or the icy ‘chaos terrains’ of Europa.

Full article here:


Alexander Tolley March 20, 2017 at 12:48

video link

As a child, I made a very similar mechanism with a cotton reel, matchstick, and elastic band. We used to run races over rough landscapes with obstacles. I used to imagine then crawling over the Moon or Mars.
These “puffer” designs seem like a high-tech version of our crawlers.


ljk March 23, 2017 at 13:24

A NASA Spacecraft Might Bounce, Crunch or Sink on Europa

Eyeing a potential lander in the 2030s, scientists are studying the icy moon’s treacherous surface.

By Alexandra Witze, Nature on March 22, 2017

Full article here:

To quote:

“For the first time in the history of humanity, we have the tools and capability to go and do this great experiment of seeing whether or not biology works beyond Earth,” says Kevin Hand, an astrobiologist at JPL. He co-chaired the new report, which is being discussed this week at the Texas meeting.

But so little is known about the surface properties of Europa that planning a lander is like planning the first Moon landings, Phillips says.


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