Hitching a Ride to the Moon (and Beyond!)

 Above, a series of ten 6-U cubesats can be seen attached to the ring which interfaces between the top of the Space Launch System (SLS) rocket and the payload fairing. It's not unusual these days for spacecraft to use extra mass allowances for these sorts of ride-along launches. It would be very difficult to arrange a special launch just for those spacecraft, so these larger launches provide a vehicle to considerably increase the science return from a space launch and to provide access to (deep) space to others. Here at PVL, we're very excited about the coming small-space era in Planetary Science!

By Conor Hayes

The launch of Artemis I on November 16, 2022 was a highly-publicized event, and for good reason. It has been 50 years since the last time we left the Moon, and although the first crewed landing of the Artemis program is not expected to take place until 2025, Artemis I is still an exciting step towards our return to the Moon.

Much less well-advertised was the fact that the Orion Multi-Purpose Crew Vehicle was not the only spacecraft riding the SLS rocket to space that night. Accompanying Orion were ten CubeSat microsatellites. The CubeSat standard was established in 1999 and has primarily been used for technology demonstrations and other missions whose higher risks make larger, more expensive satellites challenging to justify. Of course, this means that CubeSats are almost never launched on their own, instead needing to hitch a ride along with some other mission.

The ten CubeSats launched along with Artemis I were all in a 6U configuration, meaning that they each consisted of six CubeSat “units” joined together. A CubeSat unit is a box approximately ten centimetres along each edge with a mass of no more than two kilograms. This extremely small volume means that CubeSats have a very limited ability to propel themselves, so they are typically launched along with a mission that has the same target object. In the case for the Artemis CubeSats, this means that five of the ten microsatellites are aiming for the Moon as well.

So, what were the ten CubeSats that Artemis I carried into space?

ArgoMoon
ArgoMoon is a collaboration between the Italian Space Agency and Argotec, an Italian aerospace engineering company. Its primary mission is to take images of the Interim Cryogenic Propulsion Stage – where all of the CubeSats are stored – and to confirm that the other CubeSats successfully deploy. This mission will demonstrate the ability to use a microsatellite to autonomously inspect and maneuver around another spacecraft. Once deployment of the other CubeSats is complete, ArgoMoon will test the resiliency of its communications equipment in the harsh radiation environment outside of Earth’s magnetic field.

BioSentinel
The BioSentinel CubeSat mission was created by NASA Ames to examine the effects on DNA of long-term exposure to the deep space radiation environment. This is critically important information to have as we prepare for extended missions to the Moon and Mars so that we can develop methods of mitigating DNA damage to reduce the likelihood of astronauts developing various cancers and other threats to their health. BioSentinel will use two different strains of yeast as an analogue for human cells. The health of the yeast cells during the 18 month mission will be assessed by monitoring their growth and metabolic activity and comparing it to the radiation doses measured by sensors onboard the spacecraft. The results will then be compared to three identical copies of the BioSentinel experiment, one of which will be exposed to the low Earth orbit radiation environment onboard the International Space Station.

CuSP
The CubeSat for Solar Particles (CuSP) is a technology demonstration mission developed by the Southwest Research Institute. It contains three science instruments designed to count the number of energetic particles ejected by the Sun, as well as to measure the strength and direction of the interplanetary solar magnetic field. If all goes well, CuSP could justify the creation of a fleet of similar small satellites positioned throughout the Solar System to form a space weather monitoring system. 

EQUULEUS
The EQUilibriUm Lunar-Earth point 6U Spacecraft (EQUULEUS) is one of two Artemis CubeSats provided by the Japan Aerospace Exploration Agency (JAXA). Despite its small size, much science has been packed into it. EQUULEUS carries three science instruments as well as an experimental propulsion system. Two of the instruments are designed to detect the presence of dust and micro-asteroids in the space between Earth and the Moon, while the third will characterize the near-Earth plasma environment. Rather than traditional rocket fuel-powered propulsion, EQUULEUS will use water thrusters to propel itself into a halo orbit at the Earth-Moon L2 Lagrangian point and to fly-by any micro-asteroids that it discovers.

LunaH-Map
The Lunar Polar Hydrogen Mapper (LunaH-Map) was provided by Arizona State University to map water ice at the Moon’s poles. It will use a neutron spectrometer to measure the flux of high-energy neutrons leaving the lunar surface. These neutrons are suppressed by the presence of hydrogen atoms, so areas where LunaH-Map measures fewer neutrons are likely enhanced in hydrogen-bearing molecules like water. This mission will build on results from the Lunar Exploration Neutron Detector (LEND) onboard the Lunar Reconnaissance Orbiter (LRO), building higher-resolution maps thanks to its lower-altitude orbit (5 km for LunaH-Map versus 20 km for LRO). Unfortunately, the satellite experienced a problem with its propulsion system shortly after deployment, meaning that it was unable to insert itself into lunar orbit. However, there are still several months left to diagnose the problem before its current trajectory will make the mission unrecoverable. If the LunaH-Map is able to diagnose and fix the problem and get the spacecraft into orbit, the mission is planned to last for 96 days, after which it will be launched into a polar crater. 

Lunar IceCube
As its name suggests, Lunar IceCube is another mission to search for ice on the Moon, developed by Morehead State University in collaboration with the Busek Company, the Catholic University of America, and NASA Goddard. It will hunt for water ice and other volatile molecules at the Moon’s poles from a 100 km orbit using an infrared spectrometer. 

LunIR
LunIR (formerly known as SkyFire), designed by Lockheed Martin Space, is another lunar mapping mission. Its primary mission objective is to test a low-cost thermal imager that could be used to characterize future landing sites on the Moon and Mars. It will also test the use of an electrospray thruster, in which electrically-charged liquid is expelled to provide thrust, for small orbital adjustments. The LunIR team have not provided updates on the spacecraft’s status post-launch, so it is currently unclear whether or not it is operating as expected. 

NEA Scout
The Near-Earth Asteroid Scout (NEA Scout) is a NASA mission that will use a solar sail to propel itself to 2020 GE, a near-Earth asteroid approximately 18 metres across. Because it is extremely difficult to identify and track objects of this size, not much is known about them, leaving a critical gap in planetary protection plans. This mission carries a single instrument – a camera that will be used to take high-resolution imagery of 2020 GE. Unfortunately, NEA Scout failed to make contact with the Deep Space Network after deployment, so the team is currently attempting to recover the spacecraft.

OMOTENASHI
The Outstanding MOon exploration TEchnologies demonstrated by NAno Semi-Hard Impactor (OMOTENASHI; some very creative acronym work!) is the second of JAXA’s contributions to the Artemis I CubeSat collection. It was designed to be a semi-hard lunar lander, using a combination of rockets and airbags to impact the lunar surface at 20–30 m/s. It would then use an onboard radiation detector to study the radiation environment at the surface. Shortly after deployment, communication with OMOTENASHI was lost. After five days of recovery efforts, the team concluded that the spacecraft’s solar panels had failed to find the Sun, leading to an unrecoverable shutdown of the spacecraft following battery depletion.

Team Miles
The final of the ten CubeSats is Team Miles, a technology demonstration mission by Fluid and Reason, LLC. Team Miles was developed to test new propulsion and communications technologies. It will fly past the Moon towards Mars, with a goal to travel at least four million km and possibly up to 96 million km.
These will certainly not be the last CubeSats launched towards the Moon as we enter the Artemis era of lunar exploration. Indeed, there are already three more prepared for launch that just missed the Artemis I integration deadline: Cislunar Explorers, Earth Escape Explorer, and Lunar Flashlight. Although they may not nearly be as flashy as larger missions like the main Artemis flights, the proliferation of microsatellites has provided excellent opportunities for groups with less available funding to get good science done without having to compete for space onboard a more expensive mission, making off-Earth research more accessible for everyone.

What’s going on with methane on Mars?

This week, Madeline discusses a critical component of her research into how methane is vertically distributed in the martian atmosphere. Read on for some details about the present state of the ongoing debate about Methane on Mars.
(Image source: https://mars.nasa.gov/system/feature_items/images/6037_msl_banner.jpg)

by Madeline Walters

On Earth, we’ve often heard of methane being produced as a result of living beings-microbes that help with livestock digestion. Though when we found methane on Mars, we were puzzled by its origins. Are there microbes helping the digestion of Martian cattle? Most signs point to no, however, we are still unsure of what may be producing the gas on Mars. Besides biogenic sources, methane can also be produced by geological processes, so being able to identify the sources of methane is a tricky yet interesting problem.

The issue with identifying the sources of methane is finding the methane in the first place. Since landing in Gale Crater in 2012, the Tunable Laser Spectrometer (TLS) instrument onboard NASA’s Curiosity rover detected background levels and a few higher spikes of methane from the surface, however, ESA’s ExoMars Trace Gas Orbiter (TGO) wasn’t able to detect any methane from higher up in the sunlit atmosphere. 

TLS lead scientist Chris Webster [1] comments: "When the Trace Gas Orbiter came on board in 2016, I was fully expecting the orbiter team to report that there's a small amount of methane everywhere on Mars, but when the European team announced that it saw no methane, I was definitely shocked." 

The results were certainly unexpected after other detections of methane from other instruments, leading to new questions about whether the detections from TLS perhaps originated from the rover itself. Some scientists suggested the rover detected methane after crushing rocks, or perhaps wheel degradation, not willing to rule out any possibilities. However, the Planetary Fourier Spectrometer onboard the Mars Express (MEx) spacecraft observed higher levels of methane in 2013, after Curiosity also reported a methane spike, bringing back the question of how to make sense of these detections.

So why are some instruments reporting methane while others aren’t? This is something that is puzzling scientists almost as much as the source of the gas itself. Because of the conflicting reports of detection from different instruments, the key is observing how methane diffuses through the atmosphere at different times of day and through different seasons to see if perhaps the reports of methane from different instruments can still make sense.

Moores et al. [2] suggests a small amount of methane seeps out of the ground continuously such that during the day, it mixes well with the atmosphere, which results in very low levels of methane further up. Meanwhile at night, the methane can build up near the surface from the lack of convection. From this approach, we can make sense of both the ExoMars and Curiosity observations. While this could explain the discrepancies in methane detection from different instruments, we still have yet to determine the origin of the gas itself and if that origin perhaps can explain how the gas is being destroyed much quicker than it should. Because solar radiation and oxidation should be destroying the produced methane after a lengthy 300 years, the excess methane buildup should be detectable by TGO. This points to some destruction or sequestration mechanism that is getting rid of the methane quicker than expected such that the detected amounts make sense. 

"We need to determine whether there's a faster destruction mechanism than normal to fully reconcile the data sets from the rover and the orbiter," says Webster. 

One possible explanation for this is the gas’ reaction with the surface components. A chemical compound called perchlorate, which has been detected by Mars landers, may be acting as a sink for methane due to oxidation reactions [3]. When exposed to ultraviolet radiation from the sun, perchlorate accelerates the destruction of methane-from over 300 years to just days or hours. However, scientists are still exploring this possibility and as of right now, there’s still no way to be sure this is the reaction responsible for the gas’ quick destruction. While there are still many questions surrounding Martian methane, we are getting closer to explaining the mysteries of the gas.

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References:

[1] https://www.jpl.nasa.gov/news/first-you-see-it-then-you-dont-scientists-closer-to-explaining-mars -methane-mystery
[2] Moores, J. E., King, P. L., Smith, C. L., Martinez, G. M., Newman, C. E., Guzewich, S. D., et al. (2019). The methane diurnal variation and microseepage flux at Gale crater, Mars as constrained by the ExoMars Trace Gas Orbiter and Curiosity observations. Geophysical Research Letters, 46, 9430– 9438. https://doi.org/10.1029/2019GL083800
[3] Zhang, Xu & Berkinsky, David & Markus, Charles & Chitturi, Sathya & Grieman, Fred & Okumura, Mitchio & Luo, Yangcheng & Yung, Yuk & Sander, Stanley. (2021). Reaction of Methane and UV-activated Perchlorate: Relevance to Heterogeneous Loss of Methane in the Atmosphere of Mars. Icarus. 376. 114832. http://dx.doi.org/10.1016/j.icarus.2021.114832.

More conference talk. Suddenly stuck at home? Make the best of it!

We had all hoped to be in person at this year's DPS, however, the hybrid nature of the conference meant that any students who had last minute disruptions could still attend virtually. It's really nice to be able to accommodate these sorts of situations and, while the online experience is not the same as the in-person experience, it means that someone who has made arrangements and already paid their registration can still get some value out of the conference, perhaps even more value than they had expected as our new PhD student Elisa Dong attests below. For more on the picture above, see the Caption at the bottom of the article.

 by Elisa Dong

New PhD student (Elisa) checking in with the usual readers of this blog. This week I've been invited to discuss whatever I so desire on the blog. I happened to be writing something for my own blog on attending conferences. Here are a series of mostly serious tips for attending conferences remotely, when the format is hybrid and all your friends are attending in person. The backdrop for this conference was DPS, on which Conor has recently posted. A lot of these tips have been test-run during the pandemic where I attended AGU online.

Tips for attending a scientific conference (when you're remotely at a hybrid event):
1.     Identify your favourite conference snacks and drinks
2.     Purchase, make, or make student-budget friendly versions of said snacks and drinks
3.     Plan chores that require at most 1 hour of your time. Preferably a bunch of 10-15 minute chores
4.     Acquire bluetooth headphones
5.     Identify some clothes for dressing up (or down)
6.     Pick a few "key" sessions you want to be awake for and some interesting ones to pad out the rest of your time.
7.     Chat with your lab mates on your preferred communication method of choice.

Let's break these down a bit. Say you were really looking forward to attending the conference in person and had already planned for those days to be away. However, you've fallen sick or some event has taken place that prevents you from attending. You might as well try to get part of the conference experience at home! While there will be significantly less mingling with others and networking opportunities will be, at best, awkward and stilted you can still delight in the little snack breaks while reflecting on the state of the field.

This brings us to tip number 1. If you've been to a conference before, what snacks did you enjoy during the breaks? Personally I like that there are usually several tea options, and sometimes the coffee is palatable. The previous conference I had attended online (planned), I had the time to order some coffee samples and pick up a variety of snacks from the asian supermarket. This time I was stuck in quarantine, so I made sure I had a kettle and a massive stock of tea bags. This covers tip number 2 as well. It doesn't have to be fancy, but having the ability to make hot drinks on demand is quite nice. It's reminiscent of downing drinks to soothe your throat in the dry, conference room air.

Tip number 3 and 4 involve keeping yourself busy. Unlike an in-person conference, there are very few things you can look at that you are unfamiliar with. You likely won't have access to the attendees (no camera facing that way, zoom only shows the speakers) so figuring out who else is at that session is out unless they speak up during Q&A. Instead, you could be getting some mundane tasks done! I personally can't look at a screen continuously, so laundry, cleaning the kitchen, organizing bookshelves, watering/trimming plants, etc. all give me breaks away from the screen, but I'm not doing anything so critical that I can't check what's on the screen if it's particularly important. Tip 4 gives you the flexibility to move around without fear of wires tangling or blasting the audio (less of an issue if you don't have roommates, but still a nice option). Earphones are also an option, but I find headphones to be a bit better with universal fitting. Also, you now have the wonderful ability to choose to go to the bathroom while still listening to the sessions.

It's all good to be perfectly cozy while stuck at home (or if you're so inclined, going outside while still plugged into the conference). A big part of the conference experience is being present though. For me, that means dressing in a slightly snappier manner than I normally might. Regardless, I would want to have a change of pace for "conference time", much like when working from home, it's helpful for me to dress up for "work hours". Dressing down could be a fun alternative to this though. After all, no one can see that you're in the goofiest of onesies. Similarly, no one will know (other than your housemates) that you attended in a full ballgown and mask. So that's tip 5.

Tip 6 is applicable to any conference you attend. There is only so much time in a day, so pick your favourite events to go to. Figure out what's relevant to your interests. Not much more to say about this one. Tip 7 is similarly applicable always. Should you find yourself longing for some company, or wanting to experience the social aspect of the conference, checking in with your lab mates or anyone else at the conference can be nice. If you're all together (remote or in person), it can be nice to schedule some hangout time outside of the planned events.

Lastly, it's always a good idea to tap out whenever you're feeling tired. No point attending a conference in your brain is on the fritz. A copy of these tips can be found on my personal blog (soon), abstract-ed.me, where I will likely keep posting silly little pseudo-articles on science and whatever catches my interest at the time.

___

As an aside, for all potential incoming grads, here are the things that have happened in the last 2 months:
-        started taking my singular mandatory course (yay for transfer credits!)
-        met up the rest of the lab at an outdoors event and found out we're all equally bad at playing frisbee
-        confirmed that housing is as tricky as I thought it would be
-        ran into an old friend at the university!
-        had an impromptu zoom call with the founder of a company whose instruments I'm hoping to use in the near future (no spoilers!)
-        learned how to plug things into a breadboard and string things together with different communication protocols
-        moved some plants into the office, including my favourite "it's time to go home plant" (Fig. 1)
 

Figure 1 Caption. Here is my plant before I moved it to the office. The "it's time to go home plant" is an Oxalis triangularis. This purplish plant has a few relatives, but they are also referred to as "false shamrocks" when they are of the green variety. The sets of three leaves close up when the light begins to dim. This is usually my sign that I've been at work for too long during the summer months, and a reminder to start packing up during winter. I have been tricked in the past, as the leaves remain open with artificial lighting as well. They're generally pretty happy office/house plants, require moderate temperatures, nothing special in terms of humidity, and enjoy filtered light. They do grow rapidly outdoors, so don't plant them outside!

Completing the Thesis Defence: The Final Boss of a Graduate Degree

This past summer, several of the students in PVL had the opportunity to go through the timeless ritual that all us academics undergo in order to earn our MSc and PhD degrees: the oral defense of our research. I can report that everyone made it through with flying colours! Of course, a defence is also a transition for the student who may be moving from an MSc into a PhD, from a PhD into a Postdoc or from their MSc into the working world, amongst other paths. If you are considering getting a higher degree and want to know what this hurdle looks like, or are starting to think about your own defense, Grace has some helpful insight below. 
(Image above from XKCD Comics: https://xkcd.com/1403/)

 by Grace Bischof

The end of the summer marked a busy time in the Planetary Volatiles Lab. Conor, Giang and I were each nervously preparing for our upcoming thesis defences, where we would learn if we were to pass and obtain our degrees, or fail and be very, very sad. Giang, reaching the end of his PhD in August, defended first, setting the tone for the rest of us by passing! Conor and I followed, defending on September 7th and 8th (apologies to our shared committee members who had to sit in back-to-back defences). Conor and I were also successful in defending our theses, meaning we both obtained our master’s degrees. It was a very exciting end to the summer.

So, what is a thesis defence and why is it so nerve-wracking? In a research-based degree, the findings of the research you complete over several years get written up into a document – at York, this is a thesis for a master’s and a dissertation for a PhD, which is a more robust document than a thesis. This document represents years of hard work, and hopefully, makes an original contribution to the field in which you’re studying. That, in and of itself, is a nerve-wracking process. But before the university can award you your degree for all the painstaking effort you have put into your thesis, they first must test you on the contents in the form of an oral examination.

The oral examination usually begins with a public talk, where your research is presented in a 20 minute to hour long (depending on the degree) presentation. Typically, anyone can join this portion of the defence, and for me, it was fun having my friends and family watch my presentation so they could finally stop asking what it is I actually work on. Once the public talk is over, everyone else leaves the room, so it is just you and your committee. One-by-one, the committee members take turns dissecting your thesis, asking questions, and making suggestions about the contents to facilitate discussion on your work. This process can last several hours, especially for a PhD defence which is more involved. Once the committee has run out of questions to ask, you are kicked out of the room while they deliberate. Sitting outside the room while a small number of people decide the fate on the culmination of your work is horrifying. Then you are finally called back to the room to receive to your verdict…

The good news: the thesis defence is largely a formality. That is, if your research supervisor is doing their job, you will not walk into the thesis defence if you are not going to pass. The purpose of the defence is simply to ensure the student understands their work and the literature in which it is situated. Not knowing the answer to an examiner’s question does not mean you will fail the defence. In fact, the examiners want to see you reason through their questions, applying your knowledge even when you do not have the exact answer. There was one point in my defence when I answered a question completely incorrectly but realized my error once I thought more about it. I told the committee that the answer I gave was incorrect and walked them through my thought process to answer the question correctly. The committee was more interested in seeing my reasoning in getting to the answer than they were worried about the initial mistake I made.

So, now that you know what a thesis defence is, let’s briefly walk through some tips for the defence:

1. Start preparing early. The amount of time needed to prepare is going to depend on the degree being obtained – i.e., PhD students will likely need to start earlier than master’s student. Three weeks out before my defence I began to seriously prepare. I started by compiling a list of the most important references in my thesis. I read a handful of these a day, highlighting and jotting down notes on important aspects of each paper. At this time, I was also walking through the basics of the field – sure, it might impress your committee to describe in detail all the aspects of radiative transfer in the atmosphere, but that might diminish if you forget Mars is the 4th planet from the sun.
   
   
2. Anticipate questions. About 1.5 weeks from the defence date, I began combing through my thesis line by line. I had a PDF version of my thesis which I used to highlight and make notes in the margins. I wrote down anything that came to mind when reading my work and how the committee might interpret it. Some common questions that are asked in defences are: “How does your work fit into the existing literature”; “Describe your work in a few short questions”; “In what ways can this work be expanded?”; “What limitations did you experience in this work?”. Funnily enough, I prepared for all these questions and did not get asked any of them. However, preparing for them helped me to pick apart my work more carefully, meaning I could answer the questions they did give me.
   
   
3. Try to relax as much as possible. It’s easier said than done. An important tip that I read online before defending my thesis was to make sure that in your state of nervousness, you don’t consistently interrupt the examiners while they are asking questions in an attempt to quickly prove you know the answer. When an examiner is speaking, it’s a perfect time to collect your thoughts and let them talk (it eats up more time this way too!). But, like I said, the defence is largely a formality. If you’ve done the work, then you know your stuff and you will crush it! You are allowed to sit and think about your answer before speaking, drink some water or have a snack, and take a break during the defence if needed. After the first 30 minutes of the defence, the rest breezes by.

Your thesis defence will probably be the only time you will ever have a discussion with people who have ever read the full contents of your thesis. That itself is a pretty cool opportunity, so try to enjoy it as much as you can! Hopefully in four years’ time, when I’m preparing for my PhD defence, I can come back to this blog post and try to take my own advice.  

PVL in London (Ontario, That Is)

 

This week, new PVL PhD student (formerly PVL MSc student - congrats!) Conor Hayes reflects on the just completed DPS Conference that they attended a few weeks ago. This is the first time that DPS has been in person since Geneva, Switzerland in 2019 and the first time it has ever been held in Canada. I certainly appreciated being able to experience the conference together with my graduate students as a research group without even having to bring my passport!

by Conor Hayes

It has been nearly a year since I last submitted an entry to this blog, detailing my experience at GAC-MAC 2021, my first in-person conference as a grad student. Much has happened since then; I half-pivoted away from the Moon to add a new MSL-based project to my Master's thesis less than nine months before my defence, I wrote and successfully defended said thesis, and now I'm a freshly-minted PhD student here at PVL.

Some things, however, do not change, so I am here once again to talk about our latest conference experience at the 54th Annual Meeting of the Division for Planetary Sciences (DPS). PVL typically puts up a strong showing at DPS because we are all planetary scientists, and this was particularly true this year for two reasons. First, DPS 54 was held in London Ontario, practically down the road (relatively speaking) from us here at York. Second, PVL’s own John Moores was Chair of the Science Organizing Committee, so we couldn’t not represent our group well.

In many ways, DPS was very similar to the two in-person conferences that I was able to attend during my Master’s – GAC-MAC back in November of last year, and the 7th Mars Atmosphere Modelling and Observations conference this summer. The scientific program was divided between oral talks and poster presentations, with a plenary session in the middle of each day. I mostly stuck to the sessions on topics that I’m interested in – the Moon, Mars, and terrestrial planets, though I did attend a few that were more “out there” (at least with reference to my own research) on Europa and other icy moons, as well as sessions on citizen science, education, and public outreach.

Although it followed this familiar pattern, DPS was very much a conference of firsts for me. Because DPS was a hybrid conference this year, each session had two chairs, at least one of whom had to be in-person. One chair would make sure that each speaker stuck to their allotted time and manage questions from in the room, while the other would monitor the session’s Slack channel, where virtual attendees could ask their questions. Due to the continually evolving health situation, there were a number of in-person chairs who had to switch to virtual attendance, meaning that some sessions no longer had an in-person chair. Several members of PVL (including myself) were recruited to take their place. The session that I chaired was titled “Dynamical Dances in Space,” and featured four talks discussing gravitational interactions between various Solar System bodies, the first of which was actually based on a newly-published paper that I had read shortly before the conference. Stepping in as chair at the last minute was a little daunting because I had no idea what to expect, but it ended up being a reasonably non-stressful affair.

Much more stressful was the fact that this was the first time that I had been invited to give an oral presentation at a “major” conference. I’ve given presentations about my research before, but always in much lower-stakes settings, whether that be in PVL group meetings or at smaller conferences run by graduate students (e.g. York’s Physics and Astronomy Graduate Executive conference or the annual Lunar and Small Bodies Graduate Forum). On top of that, I had never presented the preliminary results of my lunar work to a larger group before, so there was a lot that I was worried about. Consequently, I spent a lot of time preparing my presentation and making sure that I stayed as close to the seven minute limit we were given. In the end, the magnitude of my stress was wildly disproportional to the actual event, as my presentation went smoothly and hit the seven minute mark almost exactly. Although I would have happily taken just that as a win, it has also inspired my first official research collaboration with someone outside of PVL, something that I am very excited about.

Now that I’ve had experience with both oral and poster presentations at conferences, I think I can say that I prefer oral presentations over posters. Posters certainly do have their advantages – you present all of your information on a single page and you don’t have to worry about time limits or making sure that you remember what you want to say, as posters often come with a more conversational style of sharing information. However, I’m just not really a fan of the poster experience. During a poster session, you’re sharing a room with many other people presenting their posters at the same time, so there’s a certain element of competing for the attendees’ attention. Some people can also find approaching the presenters one-on-one more intimidating than asking a question at an oral presentation (I certainly do!), which might limit the number of interactions you have. I definitely don’t want to turn people off of poster presentations; they can be a low-stress way to ease your way into the conference experience and/or to present early/preliminary results that are still in progress.

Overall, DPS was probably my favourite conference of the handful that I have attended (either virtually or in-person) over the past two years. I can only hope that the weather in San Antonio will take a break from its usual late-summer Texas heat for DPS next year.

There and Back Again: A MAPLE Tale

 

As we approach the final year of the MAPLE project, it's time to take the instrument out into the field! This past summer, PVL PhD student Charissa Campbell and then-MSc (now PhD) student Grace Bischof took MAPLE out to Argentia, Newfoundland one of the foggiest places on Earth where the Gulf Stream meets the Labrador current. Mother nature didn't disappoint and Charissa and Grace came back with spectacular images and science.

by Charissa Campbell

This summer was quite busy as we were preparing for the deployment of our MAPLE (Mars Atmospheric Panoramic camera and Laser Experiment) instrument to the highly foggy area of Argentia, Newfoundland. There are two main field testing sites for MAPLE which includes a foggy location (large aerosols) and Arctic location (small, Martian-like aerosols). With the Arctic being more Mars-like, MAPLE will travel alone and be controlled remotely to fully mimic spaceflight conditions. However, as a starting point, we decided to travel with MAPLE to the Argentia, NL area to test in foggy conditions.

MAPLE is based on a previous experiment done by the Phoenix lander that took images of the onboard lidar laser to classify ice-water content of aerosols near the surface (https://photojournal.jpl.nasa.gov/catalog/PIA11030). However, the camera could only take an image of a small portion of the sky, limiting the view of the laser. MAPLE is equipped with a panoramic camera to allow the full sky to be captured, which also allows for multiple lasers to be in use at the same time and clouds to be monitored during the day. For Argentia, we equipped MAPLE with 8 different lasers in a variety of wavelengths and power (class) to try to determine if a specific set was better for future measurements. Adding different wavelengths of lasers allows us to also investigate the size of aerosols. To further increase the science output of MAPLE, we will employ techniques used with the Mars Science Laboratory (MSL, Curiosity) to calculate aerosol properties such as optical depth, wind properties and others.  By using knowledge from previous Martian surface missions, we can develop MAPLE in a way to maximize the amount of returnable data in a low-cost way.

Defining a mission as low-cost means trying to find the minimal amount of power, data volume and size needed to acquire your measurements. Since we are in the early stages of the project, we created MAPLE from scratch using a pelican case which held our components. This includes a panoramic camera, 8 lasers and a raspberry pi that is used to control the camera. Several battery packs were used, one for each laser and a separate larger one for just the raspberry pi. As MAPLE gets more automated, the lasers will eventually be controlled by the raspberry pi and power can be more streamlined through just the Pi. The size of MAPLE seemed to work well, and windows had to be installed in the top for the camera and lasers to shine through. I never took construction in school, so I had a lot of late nights with the drill to push through two rectangles for the laser windows. Luckily, we already had a bubble panoramic window so I simply had to construct a properly sized hole for the window. Somehow, I managed to fully construct MAPLE and not injure myself. We also got humidity measuring packs to see how sealed the inside was. Minimal humidity was noted within the case, which is a win considering we were in essentially a cloud most times we were on the field. One concern we did have with keeping MAPLE low-cost was that the images were rather large and I only equipped the raspberry pi with a 32GB SD card. A lot of extra time was spent moving files over to a portable hard drive so we will be looking into upgrading the size of the SD card while also optimizing the size of the images. 

The field site itself was really beautiful and was a bucket list item for me as Newfoundland was the last province for me to visit in Canada. Interestingly enough, there were no rental cars available on the whole island for the 2 week we were wanting to travel. However, with the coming end of the foggy season we didn’t want to miss the opportunity to make observations. I love taking different methods of transportation and stumbled upon a ferry that travels from North Sydney, Nova Scotia to, lo and behold, Argentia. There were rental cars available in North Sydney so my colleague and I flew directly there, picked up the car and immediately took it on the ferry across to the island. We were able to get a room on the ferry itself with 2 beds, a bathroom, and the best view of the ocean. This was ideal as the ferry is about 16 hours long, overnight, so the bed was very much needed. 

Once arrived, we got settled in the town of Placentia, which was a short drive to/from the field site which was in the port where our ferry was docked. They had a cool lifting bridge that was a great backdrop for determining when the fog was rolling in. We did most of our experiments back at our arrival dock.  It was originally a World War 2 airfield site owned by the Americans, given by the British for the sole purpose of making it a Naval airbase. The Atlantic Charter was signed just outside the port which was thought to lead to the United Nations Charter (https://www.hiddennewfoundland.ca/argentia-naval-station). As someone who loves reading history, it was amazing to do the experiments in such an area. We were on one of the old runways as it was perfect for pointing the lasers in a way determine how far the lasers could travel. This was the goal for the first day on the site.

As always, something will go wrong on the field site and that was the case on our first day. When we first started testing, we expected to fiddle with the image parameters, such as exposure, to see the laser. However, no matter what we did we could not see any of the lasers in the images. We had not brainstormed what would happen in this case so we took a rather long lunch break to think about what we could do to mitigate the problem. We decided to try taking images anyways in the sun and increased the number of images taken for each laser configuration. The sun might be so bright in the day that the camera simply cannot view them in the image. We also decided to do some trial runs when it got dark. One evening, the fog rolled in so heavily that I got MAPLE all set up late in the evening. It got so foggy that it truly felt like I was in a horror movie or unsolved mysteries as I was unable to see a few feet in front of me. Images of what MAPLE could see in the dark showed how important the dark was to our experiments. After gathering a variety of images, we knew what the game plan was for the rest of the trip. 

We finished our Newfoundland trip with images in both day and night that will be analyzed further. Many questions were both answered, and the trip was extremely useful on telling us how we need to prepare MAPLE for the Arctic. The trip was a challenge but a great way to gain leadership experience. Since I was not the only person on this trip, Grace has these words to say about her time on our field trip:

“Most of the research I’ve completed throughout my degree has consisted of analyzing data acquired from space missions – whether that be temperature, data or pictures taken from the surface of Mars. Because of this, my days usually involve sitting at my computer, writing code, and generally not moving around too much. Going to Newfoundland for fieldwork allowed me to explore different facets of research that I usually do not get to explore. Working with MAPLE meant driving out to the field site in the mornings, setting up the instrumentation, and taking several experiments to try and capture the science. There is a degree of unpredictability with fieldwork that we don’t normally experience in our day-to-day work. Will it be foggy enough? Will the batteries have enough power for the experiments? Will the inside of the instrument get too humid? Carrying out this fieldwork was a very unique experience, and I am so grateful to have had the opportunity to try something new!”

 

Five Pictures from Ten (Earth) Years of Curiosity

 

The photos that our robot geologists (and robot atmospheric scientists) bring back to us from other worlds help us to relate to these places on a human scale. No one at the PVL have looked at more images of Mars than Alex and so, who better to take us on a visual trip down memory lane on this auspicious anniversary?

By Alex Innanen

August 6^th marks 10 (earth) years since Curiosity (AKA the Mars Science Laboratory or MSL, because space people love a good acronym) landed in Gale Crater on Mars. If you’ve been around the blog, you’ll know that many PVL-ers have had the chance to work on the mission (myself included) and there have been a plethora of posts over the years about what doing ENV operations is like, or what cool science MSL is doing, or other big mission events, like the 2018 global dust storm or passing 2000 sols on Mars. To add to this collection, and to celebrate 10 years of Curiosity (or 5 Mars years, a milestone reached this most recent January), I’m going to journey through some of my favourite pictures the rover has taken over the past decade.

First we have the above picture, a classic selfie. Curiosity regularly poses for MAHLI (the Mars Hand Lens Imager) to take these self portraits, which are actually mosaics of tens of MAHLI images. There’s a fantastic video of Curiosity’s arm moving around to get all the pictures that make up a selfie. This particular selfie was captured during the 2018 global dust storm, and you can see dust in the background obscuring the crater rim. This is the same dust storm that heralded the end of Opportunity’s mission, but Curiosity came through with lots of science (and nifty pictures) to show for it.

Going all the way back in time to 2012, this is a 360° panorama of Curiosity’s landing site, named ‘Bradbury’ for the sci-fi author Ray Bradbury. Right in the centre of the picture is Mount Sharp (or Aeolis Mons), the mountain in the centre of Gale Crater. Mount Sharp is made up of sediments laid down in Gale Crater over a long period of Mars’ history, and as Curiosity has climbed up it, it’s as though the rover has been travelling through that history. But first it had to get to the base of Mount Sharp, a trip which took around 2 years trundling through the remnants of ancient lakes and rivers. I love looking at this panorama because it gives a great idea of how far Curiosity has traveled – over 28 km and 600 m of elevation, now. It's also a great ‘big picture’ shot – every new location Curiosity visits is (in my humble opinion) stunning and unique in its own way, with so much new and exciting to look at. This image lets you take a step back and take it all in.

It would be remiss of me to not include a cloud picture, so here it is, my absolute favourite cloud shot. I may be slightly biased, as I was on shift when this image was planned, but it’s so dramatic, with the cliff face (called ‘Mont Mercou’) in the foreground and the glowing clouds behind. These are Noctilucent clouds, which means ‘night shining’, and were captured at twilight early this Mars year (which was actually March of 2021 – Mars years are long). These kinds of clouds are high up in the atmosphere, and are illuminated by the setting sun, even visible when the sun has gone below the horizon. This is what makes them appear to glow, still being illuminated while the rest of the sky darkens. These particular twilight clouds seem to form more readily in Gale crater near the beginning of the Mars year, something the team discovered in Mars year 35. At the start of Mars year 36 (the current Mars year) we started looking for them and were not disappointed. One of the great things about Curiosity having been on Mars for so long is the fact that we can see yearly repetitions like this and come up with a better idea of what the Martian environment is up to year after year.

Mars’ blue sunset is spectacular and well known to fans of the ‘red’ planet. But “what colour is the Martian sky?” is a question I’ve been asked more than once by those less familiar with Mars. And it’s a great question! Sometimes – like in this picture or the cloud picture above, the sky looks more blue, almost like earth’s sky. But at other times, like in the selfie or the Mount Sharp panorama, it looks more orange or yellow. There’s a few factors behind this – often images are colour-corrected (‘white-balanced’) to show what a scene might look like under earth-like lighting. This can help scientists interpret features within a scene, making them look more familiar to better compare to earth, but doesn’t accurately represent what you might see if you were standing on the surface of Mars, which would be more of a yellowy-orange sky.

Except when you get close to the sun, like in this sunset picture. Much like how earth’s scatters light, giving us a blue sky, so too does dust in the Martian atmosphere, but the blue wavelengths of light mostly scatter forwards, so the blue colour appears closer to the sun. As the sun sets, there is more atmosphere and more dust for the light to scatter through, so that blue effect near the sun becomes more pronounced. 

I’m going to finish with this absolute stunner of an image, which combines two NavCam (Navigation camera) mosaics of the same scene, one taken in the morning and one in the afternoon. They were combined to show different landscape features that are highlighted as the sun illuminates some regions and casts others into shadow. After talking about the colours of Mars, you may be wondering what gives this image its striking blue and yellow palette. The NavCams on Curiosity only take pictures in black and white – colour was added to this image after the fact to highlight the lighting changes, with blue showing morning features, yellow showing evening features, and their combination showing just that – a combination of the two. This picture is looking back down Mount Sharp towards the crater rim in the distance, and it seems like a fitting image to close this blogpost on, looking back over the last great 10 years with Curiosity.

Science is for all of us!

 This week on the PVL Blog Post, MSc student Ankita talks about citizen science, a way by which anyone can participate in scientific research and discovery.
Image Above: YorkU Galaxified Generate your own text at: http://writing.galaxyzoo.org/

By Ankita Das

Being someone who developed a keen interest in science at a very early age I was always looking for new ways to learn and contribute to the science happening in the world. By the time I was in my early teens, citizen science projects were my favorite way to spend time when I was not involved in academic work. I spent my winter of 2010 sending my friends and family a personalized season’s greetings. Except, there was something special about these messages – the text was “galaxified” using GalaxyZoo’s special tool where each letter was a galaxy from the Sloan Digital Sky Survey (SDSS). These were the little ways I would incorporate space into my daily life. But my love for science at that age went beyond generating cute galaxified texts.


Citizen science is often someone’s first introduction to hands-on science. Personally, my first citizen science projects were in Galaxy Zoo and Planet Hunters by Zooniverse. The Galaxy Zoo project involved classifying galaxies into categories by looking at its shape - something even a child can do but holds valuable science behind the activity. A lot can be revealed about a galaxy just from its shape. For example, an elliptical galaxy is usually an old galaxy where no active star formation takes place and spiral arms in a galaxy imply a rotating disk of stars. The shape classification were according to Hubble’s classification scheme shown in image 2.

 

Image 2: Hubble’s Classification Scheme for galaxies (Source: Wikipedia Commons)

Apart from classifying galaxies imaged by SDSS, my other favorite go-to project involved looking at light curves from distant exoplanets being discovered by Kepler. Kepler’s launch in 2009 marked the beginning of some very exciting exoplanetary science which continues till date. The task at hand was again simple: to look at the brightness of a star over time and determine if there are any periodic dips in the brightness indicating the possible presence of an exoplanet around the star. The excitement I felt as a young teenager “analyzing” data from a telescope launched just a year before, possibly discovering new alien worlds was unparalleled. Participating in citizen science initiatives back then gave me a sense that I was doing something important for the scientific community even as a kid. 

Image 3: Example of Planet Hunters task
(Source: https://www.zooniverse.org/projects/nora-dot-eisner/planet-hunters-tess)

Citizen science has become an important facet of research in the scientific community today with it having evolved into more creative and interesting projects as new troves of data are generated. Citizen science projects can range from activities as simple as locating constellations with your naked eye monitoring light pollution (Globe at Night) to projects that involve amateur astronomers, photographers, and programmers equipped with certain level of hardware or skill to carry out the science. In this way, citizen science involves diverse groups from our society ranging from kids to amateurs to take part in various citizen science initiatives. For the younger section of the public, citizen science projects can become their introduction to scientific projects whereas it can be a leisure activity for the relatively senior members of our society. To me, citizen science initiatives are a powerful and effective tool for scientific outreach. Not only do members of the public learn about the science that is being carried out, they also actively contribute to it, developing a deeper interest over the years in such projects. Irrespective of the diversity in participation, one thing remains the same, all these groups contribute to our growing scientific knowledge about the world around us. 

But can the general public really contribute to the cutting-edge fields in science from their homes or backyards? Yes of course! Over the years, citizen science has churned out an interesting list of discoveries which have made it to scientific journals after being reviewed by scientists. One of the most notable discoveries in the field of space science which comes to mind is the discovery KIC 8462852 or more colloquially known as Boyajian’s star (named after Tabetha Boyajian, other names include Tabby’s star and WTF star). In 2015, citizen scientists who were part of Planet Hunters came across a star exhibiting odd levels of dimming (22%). Upon closer inspection by astronomers, the object’s odd behavior continued to baffle them leading to many people calling it by its nickname – the WTF star which is apparently a reference to the paper’s subtitle: “where’s the flux” (very misleading nickname, I know!). Scientists came up with various hypotheses to explain the star’s observed light curve which included possibilities of obstructions around the star occurring from a ring, planetary debris, or dust clouds. More farfetched hypotheses included the presence of large-scale artificial structures around the star being responsible for the unnatural dimming of the star’s brightness, hinting at the existence of intelligent civilizations. Scientists continue in their attempts to fully understand this bizarre star and hence Boyajian’s star is still being studied and monitored by subsequent telescopes and projects. 

I think most of us would agree science has changed a lot since ancient times. Science which started off as independent endeavors taken up by philosophers centuries ago today presents a different picture. The days of sitting under a tree and pondering on the mysteries of the universe and scribbling down equations are long gone. Most science carried out today is in large groups, relying on observed and measured data retrieved from instruments such as telescopes, particle accelerators, and robotic spacecraft. Hence, a huge amount of data is generated and will continue to be generated as next generation telescopes come into operation. Citizen science initiatives are a fantastic way of tackling this big data problem astronomy and space science is to expected to face soon. Thus, citizen science is not only valuable for outreach but also valuable in processing huge chunks of data and making meaningful contributions to the scientific community. A complete list of active and inactive citizen science projects in all scientific fields can be found at: https://en.wikipedia.org/wiki/List_of_citizen_science_projects

Read more at:
https://www.zooniverse.org/projects/zookeeper/galaxy-zoo
https://www.zooniverse.org/projects/nora-dot-eisner/planet-hunters-tess
https://www.darksky.org/globe-at-night-2021/
https://science.nasa.gov/get-involved/citizenscience/five-extraordinary-citizen-science-discoveries
Boyajian’s star discovery paper: Planet Hunters X. KIC 8462852 - Where's the Flux? Available at https://arxiv.org/abs/1509.03622

I know what you did last summer: Grad School Edition

With May having just begun, undergraduate students are looking forward to the summer, but the situation is different for Professors and graduate students. Though few grad students take courses during this time of the year, it is nevertheless one of the busiest times of the year. Below, MSc student Justin Kerr explains why and describes some of the rhythms of graduate student life.

By Justin Kerr

“So, you are a student right? When does your summer break start?” It’s only April, and I’ve already been asked this question dreaded by graduate students everywhere three times. At least it’s not as bad as when I was on the hunt for an apartment! When you first become a grad student, you quickly realize that most people outside the realm of academia don’t understand what research based graduate school in the sciences entails. In reality, we are typically enrolled in few if any classes and most certainly do not get a multi-month vacation in the summer months. Course-based graduate programs do exist, but are much less common in the sciences and are typically excluded from receiving most of the normal funding. So, what do research-based grad students in physics actually do?

While grad students do take some courses, they typically make up the smallest portion of our time commitments throughout the degree. Here in the Physics and Astronomy program at York University, Master of Science students have the choice of pursuing a degree by thesis or a research project. In the case of a research project, students are required to take five one-semester courses throughout their two-year program. This type of degree is more common in physics programs for students looking to pursue a PhD at the same university in order to reduce course load during their PhD. It gives more variety in topics studied but allows less time for research. By the end of the degree, students are expected to have completed an original research project presented in the form of a large written document (although often somewhat shorter than a thesis). This type of degree is more common in some specific fields than others; for example, it is almost always used in particle physics, but is a rare choice in our own lab group. Personally, this is the option which I chose in order to expand my expertise in different areas of physics to support my future goals in academia. While this is the high course load option, it still means taking very few courses – the equivalent of a single semester in undergrad over two years, at least without compensating for enhanced difficulty of the material.

The thesis option instead requires only three courses be taken over the same two-year period. This allows students more time for research and development of a more intensive project. A thesis is typically longer than a research project and may involve more multiple smaller projects rather than the single one described in a master’s research project submission. Theses are also presented in a formal defense process instead of a simple submission to a supervisory committee. Completing a thesis gives a more complete research experience to students, which is more heavily valued in certain fields. In straight physics degrees, this can also be used as an option for students who are not intending on continuing in academia to provide a more complete education prior to moving to industry. Some universities other than York have very strict preferences for which type of degree is completed for moving forward in a PhD program, such as physics programs at the University of Toronto. When completing a PhD, the only option available is a thesis, and it will be much more intense than the MSc version. At York, a physics PhD requires the completion of six graduate courses, including any taken during the MSc – meaning a student who used the thesis option will take three courses throughout their four-year degree, and research project students will only need to take one. This means that thesis and PhD students are often not taking any courses at all in a given semester, and usually only one at a time if they are.

The main goal of a graduate degree in the sciences is to perform the research that will become the research project or thesis. To properly do this, we need to first perform literature searches and read many scientific papers pursuant to our planned project. We also keep up with relevant new research in our fields by reading new publications, with most graduate students often reading through several scientific publications per week. The bulk of our work is to perform our research tasks. In physics, this usually means coding, lab experiments, or some combination of the two. This is the portion of our responsibilities that means we don’t have a summer vacation! When other responsibilities do not get in the way, we are working on our research. Producing publications is also an important aspect of graduate education, which when combined with thesis requirements ensures that a good portion of our time is spent writing. We are generally expected to work roughly full-time hours (although deadlines often have something else to say about that!), with research and the associated writing taking up most of that.

The final portion of a graduate student’s responsibilities is teaching assistant duties. As part of our admission agreement and making up about half of our yearly funding are contracts to be teaching assistants for courses offered by our department or that of Natural Science, which covers science electives for non-majors. These can include grading assignments, teaching/demonstrating in a lab course, or leading tutorial sessions in undergraduate classes. The standard requirement for TAing is 270 hours per year, which usually averages out to about 10 hours per week during the Fall and Winter semesters while leaving the summer free to focus on research. In reality, much of that often ends up being concentrated into a few very busy weeks around midterm and exam grading time.

While a good portion of our funding comes from the relatively small portion of our work that is TAing, the truth is that the vast majority of our time spent on research is in fact still work. Since any of the few courses we do take usually occur during the Fall and Winter semesters along with our TAing, our summers are left free not for a summer vacation as it might for undergraduate students, but instead for a large focus on our research work. This is particularly important for those of us graduating in August such as myself who are likely to have some of the busiest months of our degrees ahead of us while we try to perfect our research projects and theses ahead of submission deadlines and defenses. The start of the summer is no better, with the start of May meaning research evaluations for all of us; these are where we must present our current work and future plans to our supervisory committee in a form of oral exam. The next time you are chatting with a grad student, make sure not to assume that they are looking forward to their nice summer vacation to take a break from the courses that they are likely not even taking!

What Has the James Webb Space Telescope Been Up To?

PVL MSc student Madeline Walters has been following the launch and deployment of the James Webb Space Telescope with bated breath. This observatory will be a boon not only to the astronomical community, but also to the planetary science community. Above: the telescope's alignment evaluation image catches not only the target star, but myriad faint galaxies in the background.

by Madeline Walters

Since my last post about the James Webb Space Telescope (JWST), the telescope has reached its observing point and made some initial observations. The Webb is currently in orbit around L2, the second sun-Earth Lagrange point which is a gravitationally stable point about 1.5 million kilometers away from us. Since its launch, the spacecraft has gone through a few metamorphoses in preparation for its eventual observations. From testing a key antenna, to deploying its sunshield, each movement and maneuver has been integral to the telescope’s success. After successfully deploying the structure that binds the Webb’s two halves together, there was enough room to begin unfurling the massive sunshield that protects the telescope from harsh radiation. 

Soon after the sunshield was fully unfolded, the Webb deployed its two sunshield mid-booms, which stretched the sunshield out to its full length. This process requires the membranes to stretch to their proper tension, taking up to two days to tighten the sunshield. "As photons of sunlight hit the large sunshield surface, they will exert pressure on the sunshield, and if not properly balanced, this solar pressure would cause rotations of the observatory that must be accommodated by its reaction wheels," writes NASA public affairs specialist Alise Fisher in a blog post on December 30 after the launch. "The aft momentum flap will sail on the pressure of these photons, balancing the sunshield and keeping the observatory steady." It is a lot of very intricate and detailed steps that are necessary for every step of the operation-and for good reason. Every part of the unfolding must work in order to get the Webb to start observing. 

The next crucial part of the mission was the mirrors. On January 5, the telescope deployed its secondary mirror, unfolding a series of booms that hold the mirror out in front of the main mirror. This secondary mirror allows light to be collected and focused into a beam, which is then pushed down through the center of the telescope to a third mirror and other smaller ‘fine-steering’ mirrors which allow light to be properly allocated into the scientific instruments. 

Several days after the secondary mirror was deployed, the main mirror’s side panels were deployed, gearing up for the alignment of all 18 individual mirrors that make up the entire main mirror. And if you don’t think the word ‘mirror’ has been said enough so far - the observatory team spent about ten days working to move each mirror segment out of their preliminary launch alignments, and a lot longer for more precise alignment after that. However, for an instrument that will bring us observations for perhaps up to 20 years, a few months of alignment is worth it. 

Now at its destination for its science mission, the Webb has woken up, turned its instruments on, and has looked out into space to provide us with its first images. Its first telescope alignment evaluation image, made to only focus on the bright star in the center for alignment evaluation, shows background stars and galaxies due to the telescope’s optical sensitivity. Although there are still many months left before the JWST delivers its first full view of the cosmos, the telescope has already gone through an incredible journey made possible by an incredibly patient group of engineers and scientists.

How to tell time on Mars

This week, PhD Candidate Alex Innanen takes on a topic that has challenged planetary scientists and science fiction writers for decades: how do you tell time on a planet that has similarities in its revolutions to the Earth but some pesky differences? Often you'll hear of researchers working on Mars time because the length of its day is so similar to the Earth's. However, the match isn't perfect and can lead to unpleasant physiological effects for some and impractical, though hilarious, fixes. There is no 'Venus Time' or 'Jupiter Time' because their days are so different from ours that it makes no sense to try. But what to do with the extra 39 minutes in the martian day? Or the extra months needed in the martian year? 
(Image above from LMD's "Martian Seasons and Solar Longitude")

by Alex Innanen

One of my favourite things to read about are different calendars and methods of timekeeping. Here on Earth, there are all sorts of different calendars – the Gregorian, which you’re likely familiar with, the Julian calendar, and various lunar, solar or combination calendars. We also keep time within a single day in different ways – the standard now is a 24-hour clock, but at various times people have tried to introduce decimal time, where each day might have ten hours divided into 100 minutes. And this is just on our own planet, where generally the apparent movement of the sun and moon in the sky can give you a sense of when things are occurring.

Unsurprisingly, when you move to different planets things start to get more complicated.

Let’s take Mars for instance. Mars’ day (called a sol) is about 40 minutes longer than an earth day. If you want to use a 24 hour clock you either have to have a sneaky not-quite-an-hour-long 25th hour, or you have to make every hour a bit longer. Which is what the Mars clock that’s used for mission planning does. But wait, does that mean each hour has more than 60 minutes? Well, not really, if you make each minute a bit longer than an earth minute, and you can do that, not by adding extra seconds, but by making each ‘Mars second’ a bit longer than an Earth second. This way you can still use a familiar 24 hour clock.

This doesn’t mean that there’s some intrinsic ‘Martian second’ that is longer than an Earth second. While the second is an SI unit, it’s fairly arbitrary, as is splitting up a day into 24 hours. It’s just what we’re used to a second being.

One thing about round planets is that local noon – when the sun is directly overhead – happens at different times in different places. This is the reason that people on Earth invented time zones, so that local noon could line up – more or less – with noon on the clock. In reality, there’s a fair amount of variation even within a time zone. For example, there is about a 20 minute of difference between local noon in Toronto and Montreal just because of their difference in longitude, even though they use the same time zone.

There are no official time zones on Mars and missions tend to use local mean solar time (LMST), which is based on the average­ length of the sol, split into 24 hours. (There’s also local true solar time [LTST], which is referenced around the local noon, but drifts from 12:00 LMST throughout the year.) There is a generally accepted time standard for Mars, called Airy Mean Time (AMT) or Coordinated Mars Time (MTC) (comparable to Earth’s Greenwich Mean Time (GMT)/Coordinated Universal Time (UTC)) which refer to the mean solar time at Mars’ prime meridian, the crater Airy-1.

The other thing about Mars is its year is almost twice as long as an Earth year, about 668 sols or 687 Earth days. There is some familiarity, though, because Mars, like earth, has seasons! But Mars’ orbit is more eccentric than earth’s – that is to say, the path it travels around the sun is slightly more oblong. Earth also travels in an ellipse, and we do see the effects of not orbiting in a perfect circle on Earth seasons – the northern summer is about 94 days long, while the northern winter is only around 89 days – but not to so great an extent as on Mars. There the northern spring is 194 sols while the northern autumn is only 142 sols, a difference of 52 sols.

So what if we want to know what time of year it is? We can actually use the position of Mars (or any planet) in its orbit to tell this – specifically a parameter called solar longitude, shortened as Ls. We can start the year at a Ls of 0 degrees, the northern vernal equinox (the start of northern spring). Each subsequent season then starts at intervals of 90 degrees for a full 360 degree orbit. This convention is used in most scientific contexts because it can fairly easily tell you if events are occurring at around the same time year after year. It also avoids having to deal with things like leap years or leap seconds, because Mars’ orbit will always be 360 degrees – that’s just how geometry works.

All of this is what’s used currently to orient ourselves in time on Mars, but there have also been a number of attempts to create calendars and timekeeping systems that could be used by people living on Mars itself by everyone from scientists to fiction writers. The calendars divide the Martian year into months – which vary in their length, and in how many months there are in a year – and weeks – again, varying in length and quantity. Some calendars use familiar names for months and days of the week, and some make up new names, or new versions of the earth names. Getting into them all would probably take a whole series of blogposts, but it is a very fun rabbit hole to disappear down.

Lunar Cycles, Tides, and the Changing World

For those located near the coasts, it's impossible to miss the influence of planetary bodies (including the moon) upon the Earth. Twice a day, the sea level rises and falls. In some places, such as Canada's east coast Bay of Fundy, those changes can be quite dramatic. Here, liquid flowing on a spherical Earth, moving under a changing gravitational potential combines with the shallowness of the sea-floor to create a low-tide line kilometers from the high-tide line. As consistent as the system may seem, this "moon-driven [...] timeless circuit of invasion and retreat" may soon combine with longer-term effects of our changing climate, as PhD Candidate Giang Nguyen describes below.

By Giang Nguyen

Our lives are defined by astronomical cycles. How fast the Earth spins about its axis dictates our daily cycle. The angle between Earth’s spin axis with respect to its orbital plane tilts either the North Pole or South Pole towards the sun. How fast the tilt alternates between the North and the South directs our habits from season to season, year to year. These effects are the most apparent manifestations of astronomical forcing in our lives, but there are weaker forces at play that affect us in more subtle ways.
 
The Moon has its own cycles as well. The phases of the moon have often been used to keep track of time and many cultures use lunar calendars to this day. However, neither the Earth’s rotation nor the Moon’s orbit are in sync with the Earth’s orbit around the sun; we have to subtract and add days year to year to keep dates consistent with the seasons. The moon with its crescent shape is an important icon for many people across the world and indeed it does have its astronomical effect on us.
 
The moon’s gravity, along with the sun’s, exert tidal forces on Earth. These tidal forces shift water in our oceans from one place to another. You can imagine water sloshing back and forth in a bathtub and this is essentially what is happening in our ocean between the continental coasts. The movement of water will resemble standing waves where each node (point that experiences minimal amplitude change) is called an amphidromic point. Tidal forcing, along with the Coriolis effect, create huge hydrodynamical systems around these amphidromic points making them very important when trying to understand tides.
 
Seas that are somewhat enclosed by land such as the Gulf of Mexico and the Mediterranean Sea experience small tides. Regions that experience strong tides include northern Québec in Canada and France’s Bay of Biscay. These are the places where tides play a significant role in day to day lives, all resulting from how the moon orbits around Earth. Tidal effects are even strong enough to affect large climate systems [1].
 
The moon’s orbital plane around Earth does not line up with the Earth’s orbital plane around the sun. The wobble in the Moon’s orbit follows an 18.6 year cycle, called lunar standstills, and can translate to significant tidal effects. High-tide floods are already a reoccurring problem in many coastal regions. During periods in the cycle where tides are amplified, the risk of tide floods are predicted to be higher than ever. The next period of amplified tides is expected to arrive in the mid-2030s [2]. When this time comes, the Earth is predicted to be warmer and sea levels higher. Therefore, it is now more important than ever to continue to study the moon and tides and see how they affect the climate and weather around us.
 
Although our lives are mainly shaped around the sun, the moon still has its own special effects on Earth. The slight deviation in the moon’s declination as seen on Earth reveals a decade long oscillation that has significant implications on tidal forcing. This, in turn, may lead to climatic feedback that may redefine our everyday lives. Astronomical cycles remain a subject of great interest and I hope we get to learn more about it resultant from our relentless exploration of Space.

References:

[1] Lin, J., & Qian, T. (2019). Switch between el nino and la nina is caused by subsurface ocean waves likely driven by lunar tidal forcing. Scientific reports, 9(1), 1-10.

[2] Rasmussen, C. (2021). Study Projects a Surge in Coastal Flooding, Starting in 2030s. NASA JPL, https://www.nasa.gov/feature/jpl/study-projects-a-surge-in-coastal-flooding-starting-in-2030s