Group2 19-1 Week3

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Contents

Notulen Tutor Meeting

  • Mogelijk nog meer problemen/requirements
  • Communicatie bij 2.1 of 3
  • Requirements kunnen constraints worden; bijv spaceX raket gebruiken geeft maximum laadvermogen
  • Aspecten waar al oplossingen voor bestaan (reis van de aarde af en door de ruimte) veranderen in side-objectives
  • Eerst de experimenten die je wilt uitvoeren (en hoe je ze uit moet voeren) op een rijtje hebben, en daaromheen het karretje etc. bedenken
  • Hoe ga je die organische moleculen vinden, met welke experimenten
  • Planning uitgebreider, met taken, wie en resultaten. Zo specifiek mogelijk maken
  • Terug refereren naar de gebruikers, en waar spelen hun eisen een rol
  • Sommige requirements zijn totaal niet gemotiveerd door gebruikers, puur door omgeving van Europa bijvoorbeeld. Hier goed onderscheid tussen maken.
  • Er moet wel een idee zijn van hoe de functies gerealiseerd gaan worden
  • (Technische) tekening/model van het uiteindelijke product
  • User Interface

Week 3 Logbook

Requirements:

1 (maybe carrying load constraint?)

2.1 keep contact with the command centre —›Long-range communication

2.2 Survive Europan surface, t.w.—›How do we keep the lander working on Europa?

2.2.1 Iono- & Magnetosphere (electromotor?)—›Is Europa’s magnetosphere of influence? https://agupubs.onlinelibrary.wiley.com/doi/pdf/10.1029/97JE03556

2.2.2 Low gravity—›How do we cope with low gravity? Calculations of non-uniform gravity https://www.reddit.com/r/askscience/comments/1okc05/what_would_happen_if_i_started_my_car_in_zero/ 2.2.3 Low atmospheric pressure—›Is Europa’s atmospheric pressure of influence? Oxygen densities of around 10^-10 that of earth (~1.801*10^23 cm^-2)(see also calculation: https://en.wikipedia.org/wiki/Barometric_formula) 3D-Plasma source-sink model: https://agupubs.onlinelibrary.wiley.com/doi/pdf/10.1029/97JE03556 Spectrometry model: https://www-nature-com.dianus.libr.tue.nl/articles/373677a0.pdf Monte Carlo model: http://people.virginia.edu/~rej/papers05/shema_sdarticle.pdf

2.2.4 Low temperatures—›How do we cope with the low temperatures? 86-132 K http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.962.8753&rep=rep1&type=pdf

2.2.4.1 Brittleness materials—›How do we cope with materials getting brittle?

2.2.4.2 Freezing of fluids—›How do we prevent internal fluids from freezing?

2.2.5 Possibly rough or slippery surface—›How do we provide enough traction on the surface?

2.2.6 Withstand tectonic activity—›How do we protect the lander against tectonics?

2.3 operate partially autonomously—›What should the lander do on its own?

2.4 operate for preferably several years, Either:—›How to maximize the longevity of the lander’s life?

2.4.1 carry enough energy—›Bigger batteries/fuel capacities?

2.4.2 Produce energy there (sulfuric compounds/ sun/ magnetic field??) Harvest fuel on-site?

3.1 Examine Europan surface—›How will we perform research on the surface?

3.1.1 Move around—›How will we move from one spot to another?

3.1.2 Take pictures (cameras)—›The tools to create pictures on-site

3.1.3 Chemical analysis—›The tools to analyze materials on-site

3.1.4 Orientation on the surface (no accelerometer; maybe gyroscope?)

3.2 Examine Europan core?—›Will we dig below the surface to perform research?

3.2.1 Dig and sail under water—›How do we get/move below the surface?

3.2.2 Take pictures—› As 3.1.2

3.2.3 Chemical analysis—›As 3.1.3

3.2.4 Stay in contact with outside world (maybe not possible at depth)—›Communication necessary at depth?

3.3 Look for signs of life—›Determine whether life or traces of it is present

3.3.1 Find microbes (microscope)—›Possibly using microscope for small evidences

3.3.2 Chemical analysis—›As 3.1.3 and 3.2.3

Users

The question who is helped by going to Europa starts by asking why anyone would want to go to Europa in the first place. Ultimately, we want to learn stuff. In particular, we want to find life outside earth. This can teach us about the origin of life, as well as help us answer the age-old question: “Are we alone in the universe?” The reason to go to Europa and not just any other satellite in the solar system (possibly much closer) is that Europa is very likely to contain liquid water. This is seen as one of the prerequisites for biological life. The first most obvious question to ask then: “Is there (the possibility of) life on Europa?” This is what the mission first and foremost should answer. Furthermore, knowledge about Europa can help us learn about other exoplanets. By comparing our long-distance observations of Europa to the on-site observations, we can translate long-distance observations of exoplanets to planetary conditions. This may allow us to more accurately predict whether an exoplanet may be habitable. Lastly, a mission to put a lander on a planetoid like Europa has never been undertaken, and hence going to Europa will be a proof of concept showing that it is possible to go such a hostile environment. This is convenient information for if we ever try to go to a similar planetoid, perhaps Pluto or an exoplanet.

In the end, we can’t know what we’ll find on Europa. Maybe it contains about as much life as the centre of the sun, maybe we find that life would be possible but never sprung up, or perhaps we find that it’s the home of the Atlanteans, who sunk their city on earth when they found earth with its dense atmosphere and high temperatures wouldn’t make for a habitable colony. Either way, it is also important to take into account the lives that we may find on Europa. It would be a pity to find all new types of bacteria on Europa, only to kill them with a stowaway extremophile hidden on the lander. Sterilised equipment

The users can largely be divided into 3 categories:

  • Those executing this and other missions (SA’s)
  • Those processing and using the results (scientists)
  • Those potentially found during the missions (life)

The vehicle must be brought to Europa in the first place. SA’s will want a solution for that. Since direct communication over this distance is not possible, SA’s will want to be able to send commands to the vehicle such as ‘Go there’ or ‘Investigate this’, which the vehicle will carry out autonomously. For ‘investigate this’-commands, the vehicle should be able to recognise ‘this’ (‘this’ being whatever object it was instructed to investigate) and know how to investigate ‘this’. In ‘Go there’-commands, the vehicle should be able to know where it is on Europa and where its destination is. Furthermore, it should travel the distance and avoid or clear any obstacles it may come across. Furthermore, SA’s will want to be kept up-to-date on how the vehicle is doing. It should be capable of sending status updates to mission control about its own state. Furthermore, if something is found to be wrong, an ability to repair the vehicle could possibly save the mission. This ability could be in a base at the landing site or in the vehicle itself. The latter would be better, as otherwise the broken vehicle would have to return to the landing site in order to be repaired, which it may be unable to do. This updating will also give information to people planning a similar mission, about the feasibility and problems that are yet to be overcome. To avoid having to restart the mission on a monthly basis to accomplish the mission goals, some longevity on the vehicle is required. Both the energy and durability should last for a minimum t.b.d. period of time.

Scientists will want information on Europa itself; the chemical makeup of the crust, the atmosphere and the subsurface ocean, and the terrain of the crust. They will also want information on whether life exists there and/or could exist. This information will also help us in the search for other habitable planets. For instance, measurements of Europa’s atmospheric density are done in terms of the column density (which counts the number of particles in a column with a particular ground surface area reaching all the way up into space), rather than the density of the atmosphere at surface level. Now, with a lander, we can determine the density of the atmosphere at surface level. This will yield a comparison between column density and surface density, which can be used for estimating the surface density of exoplanets based purely on column density. This may in the long run allow us to find new planets to colonise, to redistribute the human load on the earth.

In case we find sentient life on Europa, they will most likely want to not be massacred. (This is deduced from the simple fact that if they are a civilization that would - for whatever reason - like to be massacred, they would’ve massacred themselves already.) Some form of communication is required. Furthermore, mission command will want them not to destroy the vehicle. For that, we can only hope they won’t.

Space agencies:

  • People responsible for the journey to Europa
    • Vehicle operators
    • Executives for other missions
  • Scientists
    • Astronomers
    • Biologists
    • Biohistorians (that’s a profession now)
    • Humanity/ sociologists
  • Life
    • Civilizations

User Requirements

  • Get to Europa
    • Using the Falcon Heavy (for maximum capacity)
      • Must fit inside cylindrical capsule: (L=13.1 m, r=2.6 m)
      • Must be under 3500 kg (possibly a bit more, but if at all it’s negligible)

SA’s

  • Command vehicle
    • Autonomous execution of commands
      • Go there
        • Know current and destiny locations
        • Recognise obstacles on the way
      • Investigate this
        • Recognise ‘this’
        • Know how to and be able to investigate ‘this’ (possibly in the command)
  • Kept up-to-date
    • Recognise and report on faulty equipment
    • Possibly repair
  • Longevity
    • Sufficient energy
    • Sufficient durability
      • Things prone to wear and tear or able to run out should run for at least 2 years. Although costs probably don’t scale proportionally with travel distance of the mission, this Europa mission is bound to be more expensive than Curiosity lander, and should thus last a bit longer than curiosity (was supposed to) to compensate for increased costs. Hence, the minimum survival time of the lander should be about 2 years.

Scientists

  • Info on Europa
    • Atmosphere
      • Ionosphere
      • Density
      • Viscosity
    • Subsurface ocean
      • Density
      • Viscosity
    • Crust
      • Terrain
    • All
      • Chemical makeup
  • Info on life
    • Possibility
      • Required chemicals
      • Required environment
    • Itself
      • Chemical makeup
      • Habitat
      • Complexity
      • Enzymes
      • DNA

Life

  • Don’t go all genocide on it
    • Preserve habitat
    • Non-lethal research methods
    • Sterilised equipment

For the rest, the environmental constraints stay the same. They largely follow from

Section 3.2 - Examine European Core

To determine if we want the robot to examine Europa’s core, two aspects are important. The utility and the achievability. When it is presumably that there is plenty of life to find on the surface of Europa, it is unnecessary to dig into the core and thereby way easier to build a robot that just examines the surface.

So first of all, the utility. It is estimated that the surface of Europa contains out of a thick layer of frozen water (10-30 kilometer), with underneath a liquid ocean. This ocean is likely to contain salt. On the images of Europa, the icy layer clearly has cracks with reddish brown material in it. This likely contains salt and sulfur compounds. But there is a theory that there is possibly water floating in those cracks, which would mean that we can find liquid water there. This could be a very important theory, because when water is present at the surface, the robot doesn’t have to go through the icy layer.

Scientists have discovered that, near the equator, warmer water rises from deep within Europa. Water that is warmer and therefor lighter rises to the top, while colder water sinks to the bottom. This phenomenon is called convection. (https://www.mpg.de/7655677/Europa-heat-pump-ocean). But due to the ice cold temperature on Europa, the warm water will instantly freeze when it’s exposed on the surface.

Second of all, the achievability. When the robot needs to examine the water below the icy layer, it should make its way through the ice. The estimated thinnest layer of ice is 10 kilometer, so the robot must make its way through this. NASA has already done a lot of research to an ice digging robot and there might actually be hope for a robot with this function; VALKYRIE. The VALKYRIE is a nuclear hydrothermal drill, which works by sucking up water and heating it via an internal nuclear power source. Then the water can be squirted back down into the hole to melt more ice into water, and so the drill section of VALKYRIE slides down into the tunnel it creates. The small-scale prototype managed a digging speed of one meter per hour, but the team says that a full-scale, landable version suitable for Europa, would be larger and dig much faster. (https://www.geek.com/news/nasas-ice-drilling-europa-robot-gets-tested-in-alaska-1600265/ + afbeelding)

The benefit of VALKYRIE regarding to previous cryobots, is that VALKYRIE is able to leave its power source on the surface. The amount of energy of the previous cryobots were limited by their size and mass, while with VALKYRIE energy can be transmitted from the power source on the surface via a laser down an optical fiber just microns wide. The laser energy is used to heat water with which to melt the ice in front of it, while the water re-freezes behind it around the fiber, allowing communications and power flow to be maintained.

Currently the maximal depth the VALYRIE has descended is only 31 meters, but that was with a 5 kilowatt laser, due to budget limitations. The researchers estimate that the power needed to dig through the ice of Europa would be between 250 kilo-watts and a megawatt. With an theoretical energy transmit limit of 4.6 mega-watts through the fibers, there is high potential. (https://www.space.com/29644-cryobot-tunneling-robot-explore-icy-moons.html & https://www.wired.com/2012/04/bill-stone-laser-powered-europa-rover/)

When it would be possible to dig through the ice layer of Europa, the next part which is just as important begins: the search for life. NASA has done research in this field too, and made another prototype, which is tested multiple times on Antarctica. It is an hovering autonomous underwater vehicle, called ARTEMIS. It was built to test ideas for how to explore long ranges under an ice cap and investigate ways to look for life in environments like that. The vehicle contains a lot of scientific sensors, cameras, has water collecting systems and can measure ocean currents. So this is a very hopeful prototype. (https://www.youtube.com/watch?v=UIbjlDexpNA)

NASA probe to dive through Saturn moon’s icy plume https://www.space.com/30931-saturn-moon-enceladus-flyby-cassini.html

Experiments

Seismic experiments: these experiments will lay bare the tectonic activity that is present on Europa. While Europa is expected to harbor an ocean of liquid water under the surface, this is, up until this point only speculation. Seismic readings performed on the surface of Europa will likely give a definitive answer as to whether there is or is not such an ocean under the surface. These readings may, furthermore, give insight into the size of this ocean (or these oceans, if there are multiple), and any tectonic activity that may take place in them, such as underwater volcanoes. It goes without saying that we will likely also gain much more insight into how Europa has formed and evolved.

Spectrometry experiments: since it is not certain at all that there is an ocean below the icy surface of Europa, let alone that there is life within this hypothetical ocean, we should also perform spectrometric experiments on the ice to see what it is made of. We can then also find out whether there are biological molecules present that could kickstart or even maintain life. Perhaps we could even find evidence of life itself, in the form of complex molecules that are contained within organisms.

If an ocean is found below the ice (for example by the seismic experiments), these spectrometry experiments can also be performed on samples water. As with the surface ice, the detection of nutrients that can kickstart or sustain life may be a good find. Finding complex molecules that could be present in organisms themselves may be an even greater reward.

Photos: taking photos from the surface of Europa is not only cool, if the lander is equipped with a microscope or a likewise instrument, we may also find patterns in the ice that will explain how Europa has come to be. Evidence or traces of life may also be found, similar to how fossils and microscopic organisms on Earth provide evidence of past and present life. Of course, if it turns out that an ocean is present below the icy surface, bringing a camera into it may result in even more valuable pictures being taken.

Gas emission experiments: similar to how the Viking landers performed gas release experiments on Mars, the same experiments could be performed on Europa. If a small sample of soil, or, in this case, is, is injected with radioactively labeled nutrients, the release of metabolised molecules may indicate that life is present. These gas emission experiments can not only be performed to find organisms that metabolise to CO2, it can also used to find organisms that metabolise CO2 itself, for example photosynthetic organisms.


Planning

Week 1:

General research: we explore the topic that we chose and come up with inspiration for a research objective. (Kasper, Marco, Wouter)

Deliverables: potential research objectives

Define users: according to the topic we have chosen, define the users that play a role in achieving this objective. (Kasper, Marco, Wouter)

Deliverables: a list of users and their goals with regards to this research

Week 2:

Determine objective: from the research in week 1, determine a research objective that will be the center of your research. (Kasper, Marco, Wouter)

Deliverables: definitive research objective

Determine requirements for the research objective and its users: in order to achieve an answer to the research objective, what requirements should there be, from the standpoint of the users (Kasper, Marco, Wouter)

Deliverables: a list of users and the requirements that they have for this research objective

Planning: make a planning for the remainder of the course (Kasper)

Deliverables: a planning of things that are still to be done for this research

Consult NASA/ESA: contact NASA and the ESA for their take on how to go about designing a research mission (Marco)

Deliverables: advice from NASA/ESA to improve our research

Week 3:

More extensive user descriptions: further work out what users would be involved with our research objective (Wouter)

Deliverables: a more elaborate description of the users and their requirements with regard to the research objective

More extensive planning: work out the planning of the project in more detail. What should be done when and by who, with which deliverables (Marco)

Deliverables: a more detailed planning for the remainder of the course

Examine possible experiments on Europa: research for different experiments that can be done on Europe to examine our objective. (Marco)

Deliverables: Some experiments that can possibly be executed

Work out section 3.2: research whether it is feasible and worthwhile to perform research below the surface of Europa (Kasper)

Deliverables: a section on whether it is feasible to go below the icy surface of Europa, and, if so, what kind of research to perform there and how to do it

Week 4:

Work out chapter 2.1: work out how to establish a stable communication between Earth and the lander on Europa (Marco)

Deliverables: a description of the necessary technologies to maintain contact with the lander on Europa

Work out the list of necessary instruments: set up a description of the instruments that the lander should have, along with motivation what they are for and why they are necessary (Marco)

Deliverables: a list of instruments, along with their descriptions, functions, and why they pertain to the requirements of the users

Work out the rest of chapter 2: describe the possible problems that Europan physics pose to the mission, along with possible solutions or workarounds (Wouter)

Deliverables: a list of potential Europan physics challenges, along with solutions/alternatives for them

Work out the rest of chapter 3: how do we get around on the surface of Europa and what conclusions can be drawn from the data of the lander’s instruments? (Kasper)

Deliverables: a description of the lander’s mode of locomotion and the conclusions that can be drawn from the data it collects

Week 5:

Make coherent story: from all the separate parts in the report, create one fluid structure that reads properly and connects all the pieces in a correct and logical manner (Kasper, Marco, Wouter)

Deliverables: a preliminary report with a logical “storyline”

Week 6:

Write conclusion and discussion: write a conclusion that describes the findings of our research, and a discussion that describes what could have been done better/differently (Kasper, Marco)

Deliverables: a conclusion and a discussion in the report

Technical sketch of the lander: make a technical sketch of the lander that showcases in detail what it is expected to look like (Wouter)

Deliverables: technical sketch

Week 7:

Finalize wiki: make sure the wiki is up to date with all our findings and the report that we have written (Kasper, Marco, Wouter)

Deliverables: an up-to-date wiki

Create presentation: create a presentation, to be given in week 8 (Kasper, Marco, Wouter)

Deliverables: presentation

Week 8:

Presentation: present our report to the tutors of the course (Kasper, Marco, Wouter)

Deliverables: a presentation for a fantastic grade

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