Update from Eric

It’s been a busy last few days. In an exciting voyage, the Planetary Lake Lander sailed the 3 kilometers across Laguna Negra to the mooring at the base of Victoria Cascade, the location where it will stay for the next year. With Liam at the helm, the Intelligent Robotics Group tested the satellite, meteorological station, and other coms on route to, and from the mooring location. The entire voyage, installation, and return took over 8 hours.

Another milestone for the PLL team as the lander was transferred to its permanent mooring place at Victoria Cascade.

The first data has been sent to Ames, as it would in a real mission. Instead of using the Deep Space Network, however, the Lander is using orbiting communications satellites. Because we are still in monitoring mode, we have not restricted the bandwidth to mimic a real mission, and will probably continue at this level throughout the summer.

The lander is already probing the water column at a rate of one profile per hour. This is providing real-time data on the physics of the lake, where the thermocline is, and data for the biological team.

We have spotted areas of interest between 10 and 25 m depth; differences in water temperatures and in the amount of light that goes through. One hypothesis is that the water that comes into the lake from Echaurren Glacier and sinks because it is so dense to that level, and contains a lot of nutrients that support life there.

The intriguing thing is that we see the same sort of behavior 6 km away from the inlet. Could this current continue so far away from where it enters the lakes? There are interesting physical and biological implications of this hypothesis.

Remote Sensing Post by PLL Team Member Robert Jacobsen


Rob Jacobsen

Rob Jacobsen

Field observations and sample collection at Laguna Negra offers lots of useful scientific data for the PLL team. However, some places around Laguna Negra are inaccessible because of steep terrain and distance from base camp. PLL remote sensing uses cameras on the ground and in space to fill gaps and better complete the information about the Laguna Negra system.

One area of particular interest for the PLL remote sensing team is the influence of geology around Laguna Negra. Laguna Negra is surrounded by many volcanic and plutonic igneous rocks, such as basalt and granite. These rocks weather and erode to form smaller pieces and new compositions. Some compositions are useful nutrients for lake organisms. PLL remote sensing uses a technique called reflectance spectroscopy, which measures the unique radiation signatures of different rock compositions. At Laguna Negra, a reflectance spectrometer measures rock compositions near base camp. These measurements are then compared with satellite spectroscopy data to understand geologic compositions around the lake.

Although reflectance spectroscopy indicates which rock compositions surround Laguna Negra, it does not explain how such material enters the lake. PLL remote sensing uses thermal imaging to study the transportation of rocks and minerals into Laguna Negra. From base camp, a thermal camera measures hillside temperature changes over a 24-hour period. Surfaces with different rock grain sizes and vegetation will have different temperatures throughout the day – sands heat up early in the morning, while boulders stay cold until the afternoon. This property is called thermal inertia. Measurements of relative thermal inertia, along with surface slope angles, indicate which fine grain material is most likely to enter Laguna Negra. Combining this information with composition data from reflectance spectroscopy helps the PLL remote sensing team model the input of geologic material around Laguna Negra. Such information helps other team members understand the interactions between lake biology and lake geology.

Team: Jeff Moersch (Co-I), Robert Jacobsen (Graduate Student Team Member), Matt Smith (Graduate Student Field Assistant) University of Tennessee

 

Q&A Part II

Q. Can you share some of the details on the design of the robot(s)?
How big are the robots being designed to explore Titan? How many
robots will explore? What do the robots actually do?
A. Several different ideas have been proposed to explore Titan, from
lake landers to airplanes to balloons.  The lake lander is the most
exciting, as it would be able to float across the surface of a large
Titan lake, measuring what they are made of, and measuring the winds,
waves and changing weather. Titan is the only place where we could
actually use the same tools we use to explore lakes and oceans on
Earth on another planet!

Q. What about this project has surprised you?
A.  We have been surprised by how fast the glacial landscape is
changing in the Andes. We are able to quantify how climate change is
causing a rapid loss of ice in Andean glaciers, which are the main
water source for the people of the region.
We are also pleasantly surprised by how projects evolve and improve
from our original concept to an actual lake lander, gathering new data
and improving our understanding of the lake and its environment. Often
the path to the end product is not what you expected when you thought
up the original concept, but it is always better, and is the product
of many talented people from different disciplines (engineering,
geology, biology, chemistry) working together as a team.

Q. Is the research dangerous to you? How much of a problem is
radiation to you? How about the high altitude and low pressure? What
precautions do you need to take to live in such high altitude in the
Andes? If there are extreme weather conditions do you still proceed?
A. The UV index, a measurement of the strength of ultraviolet
radiation coming from the sun is normally considered extreme at 11:
here at the site in the Andes it is between 15 and 17. So we put on a
lot of sunscreen and try to keep as covered up as possible. Hats are
always on! The altitude is only about 2700 m, so not too high. We have
lots of changes in the weather, from beautiful warm sunshine to high
winds, snow and hail! We make judgment calls on what work to do, being
very careful to understand that weather can change rapidly in the
Andes. There is always lots of work to be done both on the lake and
back at camp, so we keep busy no matter what the weather!

Q. How does the topography of Earth compare to that of Mars and Titan?
Does the topography present different problems/challenges?
A. The Earth’s surface is shaped by plate tectonics, so we have
distinctive low ocean basins and higher terrain on the continents.
Mars and Titan are single plate planets, and so have a more uniform
distribution of topography. However, Mars, more like Earth, has had a
lot of volcanic and tectonic activity, that has formed the tallest
volcano in the solar system (Olympus Mons) as well as very deep and
large canyons (Valles Marineris). Titan has a lot of erosion from its
methane rainfall and little tectonic and volcanic activity, and so has
very low topography. Topography is challenge of you are trying to land
a rover, so the Curiosity rover had a radar to make sure the landing
site was safe. That is certainly an advantage of landing on a lake on
Titan- a very flat and safe surface!

Q. What do you do with results when you think you have something
relevant or correct but you’re not sure (in this particular project)?
A.  The scientific process always consists of forming a hypothesis and
then testing it by collecting data. Your data will tell you if you are
on the right track, or wrong, or somewhere in between. With more
information, your hypothesis changes, allowing you to ask better, more
specific questions. You learn as you go along, discussing your results
with colleagues and writing up your findings in scientific journals so
that the scientific community at large can further test your ideas.
You are always learning, always adapting to new data and new ideas.
For example, we saw that the average temperature was not changing
much, but by digging into the data, we learned that there was a great
deal of temperature changes in certain seasons, that is the cause of
the increased glacial melt. We also found fishes very deep in the lake
- 200 m- which tells us there are nutrients deep in the lake. We do
not know where they are coming from, so we are developing new
hypotheses to test.

Q&A Part I

Students from Lancaster, Pennsylvania have been following the
Planetary Lake Lander, and wrote in a lot of very good questions about
what the project.

These questions were answered by Dr. Nathalie Cabrol, the Principal
Investigator for the Planetary Lake Lander Project, and Dr. Ellen
Stofan, the Principal Investigator for the Titan Mare Explorer (TiME)
mission that was proposed to NASA last year. Dr. Cabrol, an
astrobiologist, and Dr. Stofan, a planetary geologist, are both
scientists who study the surfaces of Earth and other planets in order
to understand the physical processes, such as glaciation, volcanism
and erosion, that shape planetary surfaces over time and lead to the
development of possible habitats for life .

Q. What kind of life may be possible on Titan/Saturn/Mars? Why is NASA
(and why are you) so interested in Titan? Is NASA’s assumption that
there may have been an ecosystem on Mars or Titan before the glaciers
melted? How do we know there were glaciers? How do we know that
conditions on Mars or Titan resemble conditions in the deglaciated
lake in the Andes?
A.  We know that comets and asteroids have delivered the carbon
compounds or building blocks of life all over the solar system.
Astrobiologists believe that life requires water, a source of energy
(like lightning or volcanism) and nutrients. Life on Saturn, with its
high pressure and hydrogen gas atmosphere is not like any habitable
environment that we know of! However, science fiction writers have
thought of organisms that could live off lightning floating in the
clouds! At Titan, there is no liquid water and it is very, very cold.
However, there are liquid hydrocarbons (sort of like oil or gasoline)
and there is much about the evolution of life here on Earth, let alone
on other planets, that we would learn from exploring the undoubtedly
complex organic chemistry in Titan’s lakes. Titan can be thought of as
having conditions similar to those of Earth when life evolved, only
much colder!

Mars was very similar to Earth for a short period of time, with liquid
water on its surface, so life is likely to have evolved. But since the
time period was short, life is likely to be microbial.
There are no glaciers on Titan- its cold climate has been stable for a
long period of time. High-resolution orbital imagery of Mars has
revealed evidence of glaciers on its surface- the youngest are likely
500,000 years old. We know these glaciers must have gone through
periods of melting and sublimation. Some of this glacial ice may be
preserved under layers of debris.  This ice may still harbor microbial
life, so they would be excellent targets for a future Mars mission!
The lake in the Andes is being used to test technology to explore
lakes on Titan, while the conditions in the deglaciating lake may be
similar to those at some point in Mars’ past. And of course, they are
also helping us to understand the effects of our warming climate on
ecosystems here on Earth.

Q. What specific types of things would you have the rovers look for
that would help you draw conclusions about the possibility of life?
How can you make the rover determine what is of ‘interest’? What does
your team consider to be something of interest that you would want it
to capture? What specific experiments are you conducting that are
helping you to better understand the conditions on Mars? Will the
rover be doing chemical/spectroscopic analysis? What tests do you do
for a search for life so far away? What do you expect to find?
A. Rovers to Mars carry instruments to measure the chemistry of the
surface and atmosphere, looking for the building blocks of life- like
complex organic compounds that are present in life here on Earth.
Because we are working in an analogue environment to Mars, we are
learning to recognize the signatures that indicate life—which will
help guide future exploration of Mars and Titan. In Titan’s lakes, we
would also measure the organic content of the lake liquids. Tests for
life are both direct- a fish swimming by- as well as indirect-
measuring a compound that is being ‘eaten’ or depleted by some form of
life, resulting in that organism then expelling, or producing an
excess, of some other compound. For example, cyanobacteria absorb CO2
from the atmosphere, and then precipitate solid carbonate structures.
Other organic activity can produce methane gas, which can also be
detected easily in an atmosphere.

Q. What were the major setbacks (if any) in designing the rovers you
currently have, and how long did it take to design them? What types of
improvements are you looking for? How do you prevent a lake lander
rover from floating? What is involved with the programming of a rover
(what methods/tools are involved in getting it to ‘think’ for itself)?
How do you communicate with it?
A. For rovers, we looked at the science questions and the hypotheses
we want to test, and we design a science payload around those
questions.  Each mission has a specific scientific goal, which then
govern what it needs to do- for example, how far it needs to go and
how it needs to make measurements. Rovers do have setbacks, for
example, of the two Mars Exploration Rovers, only Opportunity is still
operating as Spirit got stuck in sand. In addition, some mechanical
parts have trouble over time with the very cold temperatures on Mars.
For Titan, our job is easy, as we actually want to make most of the
same measurements we make at lakes and seas here on Earth—which then
in turn drives the design. To make sure we will float, we look at the
chemical nature of the likely lake liquids, for Titan methane and
ethane instead of water, and design the lake lander to be buoyant in
those liquids.

To get a rover or lake lander to think for itself, we are trying to
teach them to understand their environment. You do this by having them
collect data, and then analyze it- looking for trends, and then
deviations from what is normal. For example, for measuring wave
conditions on a Titan sea, a lake lander may change how often it is
collecting data if it senses that it is suddenly bobbing more than it
had been.

To communicate with rovers or lake landers, we type lines of codes to
command them, and then send these new instructions via the Deep Space
Network- a set of antennas around the world that are used to
communicate with distant spacecraft. Every lander has an onboard
antenna system and computer, which is programmed to receive commands
and update its operations. It then in turn, has the ability to send
data back to the Earth via the Deep Space Network.

Q. Now that ice has been found on Mercury, will more attention be
given to exploring Mercury (instead of Mars)?
A. The discovery of ice at the poles of Mercury by the MESSENGER
spacecraft is very exciting. We know that some of the ice was brought
there by comets impacting Mercury, and so analyzing it would give us
information on some of the basic materials that were also brought to
Earth early in its history. Hopefully there will be follow on missions
to Mercury, but Mars remains an important place to explore, as we know
that Mars had liquid water on its surface for some length of
time—conditions which may have been conducive to life. Also, Mars is
best suited for human exploration, as Mercury experiences huge
extremes in temperature being so close to the Sun.

Q. How do ecosystems change when glaciers melt?
A. One example is that when glaciers melt, they bring a lot of
sediments and nutrients into a lake that makes the water milky, or
turbid, but those nutrients also provide what life in the lake needs.
As time goes by, there is less ice to melt, so less discharge from the
glacier, less power of transport, so less sediment and nutrients come
into the lake. The sediment settles at the bottom of the lake, making
the water clearer, but less healthy for the organisms that live there.
Sunlight can now reach deeper into the lake, which may harm some
organisms living in the lake. They may now be replaced by a different
set of organisms or they may have to move to deeper depths. The result
is generally less diversity of life in the lake. In the last phase,
very little new material is being brought into the lake, which has
become a closed system, so organisms now have to seek nutrients from
near shore plant life or aerosols falling into the lake from the
atmosphere. If precipitation stops, the lake will eventually dry up,
and a totally new and different ecosystem results. Organisms that can
adapt to changing environments will survive, while less tolerant
organisms will disappear.