NIAC Focus: Journey to the Center of Icy Moons

Exploration of an icy moon. (Credit: NASA JPL)

NASA’s Innovative Advanced Concepts (NIAC) program recently selected 13 proposals for Phase I awards. Below is one from Masahiro Ono of NASA’s Jet Propulsion Laboratory.

Journey to the Center of Icy Moons

Masahiro Ono
NASA Jet Propulsion Laboratory

In Jules Verne’s classic science fiction, Journey to the Center of the Earth, Professor Otto Lidenbrock and his company descend into an Icelandic volcano to explore it in the name of science, discover a vast subterranean ocean among other unexpected wonders, and must resiliently survive the experience to complete their mission. This is exactly what we want to do in reality on Europa and Enceladus.

Several concepts have already been studied to explore these moons’ subsurface oceans using autonomous underwater vehicles (AUVs). However, access to subsurface ocean remains to be an outstanding challenge. The proposed concept is to deploy a surface-to-subsurface robotic system, namely Icy-moon Cryovolcano Explorer (ICE), which will land on the surface of an icy moon, traverse to a cryovolcano, descend into its opening, perform in-situ science in the vent or crevasse, and ultimately deploy underwater vehicles to explore a subsurface ocean.

ICE involves three modules: Descent Module (DM), Surface Module (SM), and AUVs. DM carries AUVs and descends into a vent by using a combination of roving, climbing, rappelling, and hopping, like an experienced human alpinist. The estimated gas density of an ejecting plume is sufficiently low, therefore its dynamic pressure (< 1 Pa) would not be an obstacle for descent. SM stays on the surface, generates power by RTG and/or solar cells, and communicates with Earth. DM relies on the power and communication link provided by SM through a cable to minimize the size and weight. It is a highly autonomous agent being capable of quickly responding to a dynamically changing environment, such as episodic eruption, and resiliently handling any anomalies under significant communication latency. Once DM reaches the subsurface ocean, it launches the AUVs to explore the exotic environment that potentially harbors life.

ICE brings three unique benefits. First, it enables in-situ science in a cryovolcano vent. Although orbiters can perform in-situ science of plumes, relatively large (up to 1 μm) dust grains are hard to reach orbital altitude. Yet it is those mineral grains that carry rich information about the habitability of the subsurface ocean. Second, ICE enables the exploration of subsurface oceans by providing an access to it. Third, it enables the operation of AUVs in subsurface ocean by providing three essential services: communication, localization, and power. Since water blocks radio waves, communication and localization are particularly significant challenges for AUVs. DM of ICE communicates with AUVs though acoustic communication. DM then transfers the data though an optic cable to SM, from which the data is transmitted to Earth by radio. DM also sends an acoustic localization beacon and serves as a battery charging station, potentially unnecessitating RTG on the AUV.

In the proposed study we will (1) develop mission concepts for ICE, (2) identify the primary risks associated with the mission, and identify potential mitigations for these risks, and (3) perform a feasibility analysis for the mission, which will include performing several system trades, including one focused on the hardware platform (e.g., climbing robot vs. repelling robot vs. hovering robot), and another one focused on the autonomy software capabilities (with the goal to identify the appropriate scope of the autonomous functionality required to execute the mission concepts). These tasks will result in identifying driving requirements for the system, including candidate science targets, power needs, resilience needs, etc. In summary, we will develop a concept for ICE that elaborates and refines the science and exploration benefits descried above, and we will analyze the benefits and risks associated with realizing this concept. A successful completion of the project will mature this exciting concept into a credible element of the growing outer planets and icy moons exploration portfolio.

  • Byron

    Very interesting piece – thanks for posting! On to Europa!

  • Andrew Tubbiolo

    I think this is classic over-reach. We will spend 30 years getting things ready for this specific mission, when instead we can keep evolving less ambitious and doable mission archiectures, and after 30 years we’ll be ready to do this kind of mission. The trade off is sinking 30 years worth of funds from less ambitious missions to develop a technology base that’s less reliable because it has not flown, vs flying and evolving a flight proven set of sub systems that after that same 30 years is ready to do the task with some degree of confidence. Another example is the James Webb Space Telescope due fo fly 25 odd years after Hubble. If it fails, oh well, there goes a quarter century of unflown systems, not flown, for no good reason. Thank goodness we now have a second line of technological development to bail us out once our stupidity catches up with us.

  • Laroquod

    So we cannot even undertake ambitious ROBOTIC space programs anymore? Aren’t robots supposed to cheaper so we could do more with less? Wasn’t that why the space program went robotic in the first place? What’s next for NASA? Abolishing expensive robotic space travel in favour of mirrors and CGI? After all, we wouldn’t want to engage in any “classic over-reach”…

  • Andrew Tubbiolo

    I’m not saying that at all. I’m saying don’t choose a mission that will spend 30 years eating the lunch of other mission concepts ready to fly in the same way that Webb has stopped almost all large aperture US space telescope missions since 1998. I’m suggesting you decide, yes we want to run submarines on Europa and Titan, but there’s nuclear power for electricity, nuclear propulsion, nuclear thermal for ice penetration, the list goes on before you are actually ready for a mission. Meanwhile you’re eating the lunch of concepts ready to fly now, and tomorrow.

    Look, we’re going to get there. Develop the nuclear power sources on other deep space mission architectures that are closer to being flight ready. Develop your technology base so when you decide to send the US Navy to Europa or Titan you’re only developing one or two new technology bases.

  • Laroquod

    Where does it say it will take 30 years? Far as I can tell, you invented that figure. We have already built plenty of nuclear space hardware and then serviced it for decades.

  • Andrew Tubbiolo

    Yes I invented it. I’ve also been working in astronomy and planetary science for over 25 years. So that’s my estimate.

    Hate to break it to you, we don’t service our nuclear hardware. We make RTG’s (Radio Isotope Thermo-electric Generators.). They are totally solid state devices with no moving parts. The USSR was the last space program to operate a real, full up nuclear reactor in space. I don’t think the US has ever done so. Look them up, there’s a HUGE difference in performance and complexity between a reactor and an RTG. I’d wager 80% of the humans on this planet who have operated a nuclear reactor in space are dead. The other portion who are alive are either geriatric or under security oath to the RORSAT program. We’ll get no help from them. When it comes to space nuclear power reactors, we’re starting from scratch.

  • Paul451

    The USSR was the last space program to operate a real, full up nuclear reactor in space. I don’t think the US has ever done so.

    Snap 10A.

  • Andrew Tubbiolo

    Very cool, thanks for the correction. Not even a kilowatt, and flown 51 years ago. We’re going to need 10’s of kilowatts electrical out of something that sized if we’re going to get the power densities we’ll need for going to gas giants, braking into their moon systems, orbiting the moons, landing on the moons, then heating your way thru km’s of ice. Then operate a submarine in an ocean we know nothing about.

  • Aerospike

    Have you read the proposal past the headline or even looked at the image?
    This “new”? proposal does not involve any heating through ice. In fact the words heating, melting, penetration and nuclear don’t even come up once.
    Basically they want to land close to a cryo-volcano, and have a tethered robot climb into it. Of course there are many unknowns with this approach, but my (un)educated guess is, that the biggest challenge would be to get the probe to one of the icy moons and land as close as possible to a cryo-volcano.

    We have operated a probe for years around Saturn and we have landed probes on Mars, Moon and Titan. So landing a probe on Enceladus or maybe Europa should not be borderline impossible.

    I totally agree with your opinion that we should not invest in long term development of missions at the cost of near term missions and your JWST comparison is a good one.

    But getting a probe to land on one of the icy moons in the outer solar system should not be something that takes decades of development and having one experiment try to have a robot crawl into a cryo-volcano could be a nice add-on.

  • Patrick Wright

    Your comments are all spot-on. I think one of the benefits of studies like this is that they lead to the smaller pathfinder projects that have to be flown before something like this can even be considered seriously for flight. Just looking at the cartoon made me think 2040 for an actual mission.

  • Laroquod

    So these solid state devices have worked for decades with little maintenance. Didn’t you just prove my point? And astronomy and planetary science aren’t rocket science: is this project leeching funds from your favourite telescope or something?

  • Like the idea. Recent calculations show we can do it at remarkably reduced delta-v and therefore mission size using Earth, Venus, Mars flybys:

    Wouldn’t need the SLS then. Could launch on the Falcon Heavy, at a much reduced cost.

    Bob Clark