Remembering Simon Krughoff

Earlier tonight we lost our wonderful, bright and caring friend and team-mate Simon (@KSK) to cancer. To those of you feeling his tragically early loss, I am so, so very sorry. My heart goes out to Gin, his wife and his rock (to use his own words) as well as his children, Sam and Owen, of which he could not have been more proud. I will let you know the family’s wishes for honoring his memory as soon as I can and if there is anything we can do for them at this dreadful time. (Update: see comment below: Remembering Simon Krughoff - #27 by frossie for details or just visit

Please excuse this rambling and hopelessly personal recollection of some good times with us in DM. I hope it will encourage some of you to add your own happy memories (if it would not make you uncomfortable) so we can share them with each other and his family. I beg you to pardon any faulty recollection on my part.

When Construction started on what was then called the Large Synoptic Survey Telescope in 2014, Simon was a staff scientist at the University of Washington in Seattle, and had already contributed to the project in its R&D phase - besides Data Management work he contributed to the Sims team whose work was vital in early software development and science planning. When I joined the project in mid-2014, Simon was my opposite number at UW, running the Seattle-based DM team focussing on Alert Production. Simon would sometimes try to convince me he was poor team lead; that worry was more a reflection on how seriously he took the role rather than reality. He was highly conscientious with the responsibilities of his position, a great peer to us other T/CAMs, and all his people I ever spoke with felt well looked after.

Around 2017, to my delight, Simon expressed an interest in joining SQuaRE in Tucson. He and Gini have family in the area, but he also wanted an opportunity to return to more hands-on work, much as he agonized about leaving his UW friends. Simon eventually joined us as as the SQuaRE science lead and as such contributed to more areas of the project that I can be trusted to enumerate: from being a product owner of the Science Platform at its critical early phase, to patiently training engineering folks on our summit EFD system, sustained contributions to the DM Science Team and its verification efforts, lending a hand to other developers with services like rubin-tv, and taking part in a number of important working groups including the one for the Gen3 Butler. He was a central part of the efforts that resulted in our team awards and his sense of ownership in this project’s success was second to none. He is, and will always remain, an LSST builder.

The above might have told you some of what Simon accomplished, but not what it was like to work with him. Let me try for those who have not had that pleasure, though I know it will be a poor attempt (and even more of a personal view).

We unfortunately work in a field that does not always visibly reward pro-social behaviour - the good guys if you will. The outpouring of love and well-wishes we received on Simon’s illness showed me that it is nevertheless rewarded in other ways - with the affection and respect of your peers. Simon was a fantastic work partner - no matter what the problem was, he was always ready with a “How can I help?” to my gratitude. Offering his help to anybody who needed it occasionally got away from him, and I knew my assigned role, in his eyes, was to go “You don’t have time for that! You can’t help everybody! I’ll tell them no right now!” until we negotiated a bit and there were enough hours in his day again. This dynamic apparently led one colleague to ask Simon whether he was being bullied - his evident (and oft-revisited) mirth he derived from that exchange extinguished any indignation at the suggestion on my part. In truth, I found it impossible to say no to Simon - he was an indefatigable advocate for our users’ needs in a polite but nevertheless irrefutable manner, while never asking for more that the team could reasonably give.

His gloriously deadpan sense of humour did not shy of the occasional mischievous trolling; never more when we engaged in that most difficult of Data Management pursuits - naming things. You see back in the day, DM had been discussing giving a snappier name to the LSST Science Pipelines. Simon and Jim (I think?), had thrown OSPRAE into the ring - Optical survey pipeline Reduction Analysis (Environment? Execution? something like that) pronounced osprey at any rate. Simon loved that name, advocated for it unusually strongly by his standards, and was bummed when for (understandable!) reasons it never quite happened. Ever since then, whenever we were having trouble naming some random package Simon would look deeply thoughtful, and then slowly, as if the name had only just occured to him, would muse “How about… Osprae?”. I fell for the punchline every time. I wish we’d done it.

After a notorious conference incident when his own (then little) kid briefly mistook colleague Matthew Graham for him, Simon derived an impish pleasure in sowing that particular confusion; our office receptionist had her work cut out for her when they were both in the building.

It’s a bit of a team hobby to fill in my considerable gaps in US culture exposure; Simon contributed among many other things fill-at-the-pub growlers (which he would turn up with when I was forced to disclose my fridge had nothing more than cerveza and Barrio Blonde, the latter being the worse sin in his eyes); mutant so-called sandwiches with absurd-to-me quantities of meat in them (a legacy of his Pittsburgh grad school days I think); and NPR Tiny Desk Concerts. That last one was a small indication of his considerable love of all kinds of music. It might surprise you to know that he was also a fantastic singer - and the computers agree with me: until the pandemic put an end to it, we’d often get together to play the video game Rock Band. His ridiculously good pitch control racked up the scores (and boy, did video gaming bring out his competitive streak) - at least unless Love Shack came up; don’t get me wrong, he still racked up the score for that, but his rendition of it was so outrageously unrestrained that I, at least, couldn’t remotely focus on what I was meant to be doing. We would occasionally joke about an All-Hands (later PCW) karaoke night. I wish we’d done that too.

After he became too ill to work, he seemed to find much solace in music. On better days he was able to work with a mixing deck that seemed hellishly opaque to me; he never seemed to lose his curiosity and willingness to try and understand complex things.

It’s heartbreaking that he didn’t get to see this wonderfully complex thing we built with him.

And so. If you didn’t know him well, I hope that gave you a small glimpse of him. If you knew him and careed for him, I hope it made you feel less alone. Please be particularly kind and forgiving of each other’s mode of expression in the comments (or their absence from them), people process their sadness in different ways and all are valid.


Thanks for posting this, Frossie.

Any words of mine feel inadequate to the situation, but for what it’s worth: as Simon’s peer as a T/CAM and later successor at UW, I found him an inspiration. He really cared, not just about the science or the instrument but about the people. When he was handing over the reins at UW to me, it was clear that his concern and affection for his team was really something that anybody in a management or leadership role should aspire to — I’m still trying to live up to his example.

Every interaction with Simon was fun, thought provoking (even when he was wrong — I mean, OSPRAE? seriously? :roll_eyes:) and rewarding. I’ll miss him a lot, and my thoughts go out to his family, friends, and colleagues across the project and beyond.

Thanks for everything, Simon.


Just a brief note for now.

Simon believed in a manager’s role as removing blockers and frictions (including me, sometimes) from the path of his team. That forward-pushing energy was critical to making progress in a number of areas. He was also unafraid to call out disrespect or insensitivity.

On the less formal side, as evidenced by one of Frossie’s pictures above, he was a key part of Game Nights at the PCW, always bringing interesting new games and enthusiastically teaching them to us.

I was already missing interacting with him. I know I’ll continue to stop to think “what would Simon say”.

Echoing John: Thanks for everything, Simon.


Thanks for posting this, Frossie and also just a very brief note.

Simon and I started working closely together in the early days of DESC to establish the simulation effort and working group (and he was key to DC2) and I learned a lot from him in so many ways. We continued working together in different areas over the years and he will be deeply missed.

Just again echoing the messages above: Thanks for everything, Simon.


Simon always took the time to mentor me during my summers at the UW; he was so patient and generous. This breaks my heart.


Simon helped recruit me to come to UW in 2017 to co-lead the AP team with him. It was easy to say yes. Just as I started, he got the offer for a new role in Tucson, which was clearly the right move for him and his family. I was struck at the time by how concerned he was about the impact of his decision on me, but as we worked together over his last six months at UW it became clear that he always put the well-being of his teammates first.

In the years since Simon’s departure I have learned how challenging it is to make good hires and to build and maintain a cohesive team. The core of Rubin’s AP group are folks that Simon hired, and I feel his influence on the people I am lucky to work with every day. In that sense I feel Simon is still looking out for me today.


I felt a strong kinship with Simon as we had traveled in many of the same circles, just sometimes out of phase. Simon and Gin spent a short time in Chile towards the end of our time there, and they quickly became part of that expat community, where they changed all of our lives for the better by introducing us to the game Cups. When we bought our house in Tucson, one of the things we looked for at the time was a space to play in the back yard.

They then moved to UW in Seattle, where Dara and I had both been grad students, and thus we shared many of the same connections, friendships, and types of experiences. UW is a special and close-knit department, and Simon fit in really well.

When Simon took a job with the SQuARE team in Tucson and the family moved again, our sons ended up in the same elementary school where they became good friends, and would go trick-or-treating together, play games online, or look for adventure in the neighborhood.

Our lives thus seemed intertwined. Losing Simon at this young age is heartbreaking and jarring.


After the pandemic, when only a few of us were back in the office, one day, Simon forgot his card and couldn’t enter the building. Then he texted me to open the front door.

He was outside wearing his hat and sunglasses, energetically waving to Maria, our receptionist, while she refused to let him in.

“- Don’t open the open door!” - said Maria to me.

He scared her out of her pants, understandably.

“- Oh, it’s just Simon.” she said, relieved when she finally recognized him.

I miss you profoundly, my dear friend, and I wish you could enter that door again for many years more.

Simon was a fantastic person, teammate, and friend - just Simon.

At work, Simon was the SQuaRE Science Lead, always so proud of everything our team did. He wouldn’t hesitate to write a notebook to demonstrate a new functionality or represent us whenever needed.

Simon was a scientist with engineering aesthetics who understood the importance of building software infrastructure and services. And he loved that. His vast knowledge of the project and willingness to always help made him a joker. He could do anything, literally.

I admire him for all that, but I want to make sure everyone knows that he was the sweetest person I ever had the opportunity to work with.

Like many of us who chose Tucson to be home, Simon too was a lover of the Old Pueblo culture, especially the food.

In the good old days, when we were all here, we used to have lunch around town. One of my sweetest memories was driving back from Quesadillas - one of his favorite places - listening at full volume to Al Perry - We Got Cactus.

Thank you so much for showing me that song, my friend. It resonates here because… “The spring without flowers is just as remorseful… and the Summer is painful, when the wind won’t blow.”

Thank you for everything!


I’m on parental leave right now and ignoring most work-related things that cross my radar, but this sad news found its way to me.

Simon hired me to join the UW AP team as a postdoc in 2016, and not 6 months into my new role, after he had patiently explained the big picture AP pipeline to me (maybe once more than he strictly ought to have needed to), I found myself nervously informing him I was pregnant. I’ll never forget how he just beamed at me, because he SO loved being a parent and was thrilled I was undertaking the same journey. There was zero hemming and hawing about my impending absence or commitment to LSST or anything like that. Now that kid is 5, my second is 2 months, and it’s no small thanks to Simon that I’ve been able to both grow into my role as a mother and contribute meaningfully (now as a research scientist) to the UW AP team.

Cancer is the actual worst, and unfortunately I know what it’s like to lose a parent to it. Though we hadn’t directly worked together in years, Simon’s sincerity, kindness, and wicked sense of humor will be sorely missed. Much love and deep peace to all who are grieving.


What terribly sad news. I really valued Simon and will miss him. I knew he had been ill, but didn’t know the details. I wrote him a while ago just to let him know I was thinking about him and a few months ago told him about some new episodes of a podcast we both liked. He told me that it made him happy, and I was hoping he was getting better.

When I first came to work on Rubin, I was working alone in a new field for me. Simon was one of a small group of people that had come together online in Rubin’s precursor to slack to enjoy each other’s company. We also helped each other when we needed it. Simon was always so generous, friendly and helpful, even when I was asking about things that everyone else knew. Later, I worked closely with him on issues related to simulation and he was always there to commiserate with when we needed to work through difficult problems that came up.

My favorite memory of Simon is a bit strange in retrospect since it was so uncomfortable for me at the time. I had come to my first meeting in Tucson and it was extremely hot. The group of us who were there all went out to lunch together downtown and Simon said he could drive me. We walked to his truck which for some reason at that time was without air conditioning. Simon was happy showing me things and chatting as I tried to survive with the windows open. By the time we arrived and were seated at the restaurant , I was really out of it but Simon was so friendly and happy that I always remember that lunch and trip very fondly and often tell others the story.

As we get older, it sadly seems we gather an ever longer list of friends and colleagues who have left us. For me, I always try to continue to remember those people, but also to try to take the best I saw of them, and incorporate that into my own life. For Simon, that will be how he approached helping others.

May his memory be a blessing and may his family find strength in this time.


When I first started in Data Management at Rubin, Simon took me out for a beer and a long discussion to find where I would fit in with the team, and discuss what I wanted out of the position. Simon was a mentor to me, and a model whose wealth of knowledge, curiosity, patience, and kindness always inspired me to be more like him in my interactions with others. I’ll miss his sense of humor, smiling face, soothing demeanor, and his wealth of knowledge that he was always willing to share. Plus I never got to fully appreciate his expert knowledge of (hard) ciders (especially, but not limited to, Washington ciders).

I’ll always remember Simon with fondness and admiration, and forever curse the scourge of cancer that extinguishes lights like his from the world.


I will always remember all the help I received from Simon when I was struggling trying to get something from DM on CFHT data ! Simon was the kind of person who always radiates sympathy and kindness, these persons who are the pillars of a project and make the world a little bit more bright. It is a terrible loss and and I am very sad. My deepest sympathy is going to his family.


This is truly sad and a real loss to the Rubin Project, friends, family and all of those Simon touched without knowing. I will always have in my minds eye a vision of Simon as a warm woolly bear with unending kindness and patience. Simon graciously and patiently helped me on many occasions to get up the learning curve of the Rubin software. During these times Simon and I would engage in wide ranging topics from welding two pieces of metal together, baseball and other sports and baking bread. These conversations just scratched the surface of Simons natural curiosity of the world around him.

It is with great sadness that this news is received and I will miss him with the warmth and and kindness he always brought to any setting.


I am deeply saddened to learn of Simon’s passing. He was a tremendous friend, colleague, and mentor. Simon’s contributions to Rubin Observatory are far reaching and almost impossible to measure in part because he routinely went out of his way to help others. Simply put, he made everyone around him better. We have so much to learn from his example.

I had the opportunity to work closely with Simon during the conception and initial development of a science verification package in the Science Pipelines. This was one of the first projects to fully use the new (at the time) Generation 3 middleware and Simon was essential to understanding the opportunities of this approach. I recall days of a small group of us in a conference room in Tucson sketching out the concept on a board and Simon hacking away at a laptop stubbing out the first classes of the new package. I also remember Simon sharing his latest ideas for visualization capabilities on the Rubin Science Platform and developing tutorials for the first “Stack Club” notebooks. Again, Simon was a technical wizard and was one of the first to envision the full scope of how scientists would interact with LSST data. Simon was a mentor to me as I was learning the Science Pipelines and helped to establish many other links between commissioning and data management efforts (e.g., developing first-look tooling for evaluating data quality on the summit). Simon was so knowledgeable, patient, and willing to share ideas that he quickly became a hub within any team that he was part of.

Beyond his outstanding contributions in so many areas of Rubin Observatory, Simon exemplified kindness, creativity, generosity, and joy in learning something new, and these parts I miss terribly. Sending my heartfelt condolences to all his friends and family.


Thank you Frossie for starting this - it brings back so many memories. I first met Simon when he was visiting Chris Miller in Pittsburgh and Chris thought it would be good for me if I took Simon on as a postdoc (I think Chris would admit it was one of his better ideas). We worked in Pittsburgh for a few years before the group moved to UW in 2007. Even back then, Simon had a natural affinity for mentoring students and other postdocs. Many people know him from all the work he did for Rubin leading the alerts team at UW and then as SQuaRE science lead but his impact was much larger than that. He was one three astronomers who built and released Google Sky in 2007. Back in 2010, he created a web based visualization platform for browsing through data that was years ahead of anything else (I found his walkthrough of the capabilities still on line). He developed a very clever way to find supernovae buried in SDSS galaxy spectra and he started up much of the simulations work for Rubin and DESC.

Simon had this unique ability to just make things work - he was a remarkable scientist. Our group liked to talk. We would debate all of the possible bugs and issues that might explain some problem in the data or software. He would just work through the code and then explain what was wrong (we were usually still talking about it by the time he had resolved the problem). He could turn his hand to anything whether software or rerouting the stream that ran under his house in Seattle. On top of this, Simon had an abiding desire to help people, which you could see in the work he took on and in how he led his teams. As everyone has said here, he thought about the people who he was working with and how to support them all the time (including telling me when I could do better - in a gentle way).

Working with Simon was a privilege, but it is the things he did outside of work that I will remember the most. In Pittsburgh, he would head out in the summer for a few days for a canoe race in the middle of nowhere. Not the usual kayak version but kneeling in a canoe and paddling for several days down rapid after rapid. It sounded a terrible way to spend a week in the summer but Simon loved it. In Seattle, he played video and board games, competed at ultimate, explained (frequently) why ultimate should be self-refereed (it really doesn’t make any sense), and had a strange affinity for sandwiches with large amounts of meat. The latter of these manifested as field trips for Caribbean roast sandwiches from Paseo, though Simon was equally adept at grilling, roasting, or smoking any quantity of meat for any number of people. One of the things that will always stay with me was his passion for keeping fish - my younger son’s first fish tank came from Simon. I will miss going round to his house to see his fish tanks, which dominated the room, or to have him explain how to do home repair or just to have a beer. I will miss his laughter and his smile.


I knew Simon from working with him on the Virtual Observatory project, starting in around 2005. Simon was someone I am grateful to have known in the brief time our lives crossed paths. I was always, always so delighted to see him. Just to think of seeing him walk into a room makes me smile like I did back in the days we worked together. Seeing the photos posted in this thread does the same. As was mentioned in the original post here, it’s true it wasn’t always an environment that rewarded pro-social behavior - but Simon embodied the exception that proves the rule. He was truly a Good Guy.

On the occasions we met, we bonded over our Maine connection, and having grown up in Boston I always appreciated the Red Sox cap he wore. His humor and dedication to doing whatever he was doing the best he could were inspiring and endearing.

There were many meetings and trips where I got to hang out with him, but my favorite memory is from one of the NVO Summer Schools in Aspen, Colorado. He and Chris Miller would take advantage of the breaks and go down to the stream behind the resort to fish. I wasn’t a fishing person, but I asked if I could go with them one time. I think the time I went it was just with Simon. We didn’t talk much that afternoon, and no fish were caught, but I remember it as a sweet bonding moment, a peaceful lesson, and a treasure in time.

This one hits hard, even though I haven’t seen Simon in many years. My heart goes out to his family, and I hope he knows how much people appreciated him.


Oh Simon; always reliable, helpful, and kind. We’ll miss you.

I didn’t know Simon loved to keep fish (thanks, Andy). All I knew about Simon and Fish came from his lovely “Not Work” talk on a summer job electric-fishing for a fisheries project, a rather less harmless way to interact. Maybe he was making amends?


Simon and I started on LSST at close to the same time, way back in 2006/2007. We shared an office for most of the time until he went to Tucson. He really was just the best office mate, and I am so glad that I bribed him with the window spot during an early-on UW office re-shuffle. He inspired me to learn so many things that were new to me then and have been incredibly helpful since, and had a real impact on my work.

He absolutely was such a kind, fun and smart person and we had so many good conversations, from work stuff to parenting, from boats to ultimate to biking and on. At some point we dreamed up the multi-day event “Feats of Lake Washington” which would be composed of a canoe race in the lake with portage section (across part of maybe Montlake?), a bike ride which would go around Lake Washington and include stops at some of the breweries, and a run across the lake on I-90 (or I-520 now). There might have been a swim across the lake as well, although I can’t remember if it seemed redundant with the run or not. It might not be all in one go, but when I visit Seattle, I’m going to try to pick off these feats one at a time, although they may be a bit modified (because come on, I am not carrying a canoe across Montlake, especially not by myself).

He and his family will always have a big warm and fuzzy spot in my heart. I will never forget him and Gin visiting and bringing me and my partner a meal when my first child was about a week old. At the time I think his oldest kid was a few years old, so they were much more experienced in this parenting thing and I was at that spot when you first have a baby of “oh my god, we’re never going to do anything other than try to sleep, eat, and feed a baby ever again”. And Simon and Gin came over and told me how cute Seren was and gave us food and told me sympathetic stories of their kid projectile vomiting that made me feel like we weren’t doing so badly and it would probably be ok. It meant a lot.


From 2009, at UW. I think Simon may actually be wearing one of those canoe race t-shirts?
I think this was a photo I took for our photos for the UW LSST group webpage at the time.


I am deeply saddened to hear of Simon’s passing. I would like to thank him for making me feel at home while visiting UW many years ago. I really admired how the team worked as one and Simon was key for that to happen, he was a very positive person who cared about others. We had some really productive discussions back then about image subtraction, astrometric solutions and dipoles.

I would like to extend my deepest sympathies to his family.