Top all-time · #3353
SimScale
Company blog · simscale.com/blogsciencebusiness
SimScale is the company blog at simscale.com, writing about science and business. Since 2015, 22 different Hacker News readers have linked it 27 times. It is still writing: the last post was on 2026-11-02, and you can follow it by feed.
Too few sampled comments (15) to say how often HN recommends it.?
Why HN links it
HN commenters link SimScale's blog post on the NASA Mars Climate Orbiter loss, caused by a metric and imperial unit mix-up. They cite it as an example of unit errors in engineering and software.
Summarised by Claude from a sample of 15 HN comments that link here. Each comment is marked recommending, critical or neutral (citing without judging); how this works.
SimScale is AI-native, cloud engineering simulation software for CFD, FEA, thermal & electromagnetics. Run simulations in your browser.
Most-linked posts?
- /blog/2017/12/nasa-mars-climate-orbiter-metric/7 people · 7 mentions · first linked 2020-01-20
- /blog/nasa-mars-climate-orbiter-metric/5 people · 5 mentions · first linked 2023-04-06
What Hacker News says?
And knowing the difference is an important part of rocket science: https://www.simscale.com/blog/2017/12/nasa-mars-climate-orbi...
Comment linking /blog/2017/12/nasa-mars-climate-orbiter-metric/
on “Perseverance Rover lands on Mars [video]”Submitted Why the Swedish Vasa Ship Sank – An Engineer's Explanation as a story · 58 points
HN discussionThe problem is one of readability, not memorization. A lot of readability amounts to taking what the initial author already knows and expressing it so that it's easy for everybody who comes after to know too. Making implicit units explicit is a great example of that. Look at Martin Fowler's writings on Money types, for example. Or look at the $125 million failure of a space probe because people used implicit units:…
Comment linking /blog/2017/12/nasa-mars-climate-orbiter-metric/
on “Please put units in names”Submitted What Is the Venturi Effect? as a story · 2 points
HN discussionSurprising, I thought they do, especially after these kind of incidents: https://www.simscale.com/blog/2017/12/nasa-mars-climate-orbi...
Comment linking /blog/2017/12/nasa-mars-climate-orbiter-metric/
on “Crew Dragon launch escape demonstration”Submitted Simulation in your browser as a story · 2 points
HN discussionI read comments and many are saying "is it urban legend" I do not think so, we underestimate people ability to complicate things and make mistakes. Does anyone remember story how NASA lost 125 million orbiter because measuring unit mistake> https://www.simscale.com/blog/2017/12/nasa-mars-climate-orbi...
Comment linking /blog/2017/12/nasa-mars-climate-orbiter-metric/
on “A Short Story for Engineers”Submitted Formula One Aerodynamics 2017 Webinar as a story · 2 points
HN discussionYou mean like the 125m Mars orbiter lost due to engineers forgetting imperial/metric conversion? https://www.simscale.com/blog/2017/12/nasa-mars-climate-orbi...
Comment linking /blog/2017/12/nasa-mars-climate-orbiter-metric/
on “USPS Files Patent for a Blockchain-Based Voting System”Submitted NASA Lost Its Mars Climate Orbiter from a Metric Error as a story · 1 points
HN discussionAssociate professor in fluid dynamics here. There is typically a split between the people who want good looking simulations for movies/games, and those who need accurate results for engineering. For engineering, you need more effort on how you resolve the complex geometry and how you model the turbulence in the flow. This adds significant complexity both for problem setup and solution time. The only product I’m awar…
Comment linking /
on “WebGL Fluid Experiment (2014)”Submitted Smarter Snap-Fit Design Using FEA as a story · 1 points
HN discussionAlso newtype wrappers. If you have code that deals e.g. with pounds and kilograms, Dollars and Euros, screen coordinates and window coordinates, plain text and HTML and so on, those values are usually encapsulated in safe wrapper structs instead of being passed as raw ints or floats. This prevents you from accidentally passing the wrong kind of value into a function, and potentially blowing up your $125 million spac…
Comment linking /blog/nasa-mars-climate-orbiter-metric/
on “Rust solves the problem of incomplete Kernel Linux API docs”Submitted Formula Student Aerodynamics – Growing Wings with CFD as a story · 1 points
HN discussionI'm sure it was picked a long time ago and it's too costly to switch. I imagine any code going into multi-million dollar missile needs to be incredibly audited and understood. (Not that this never happens! https://www.simscale.com/blog/2017/12/nasa-mars-climate-orbi... )
Comment linking /blog/2017/12/nasa-mars-climate-orbiter-metric/
on “There are over one trillion SQLite databases in active use”Submitted Aerodynamics of Cycling Explained as a story · 1 points
HN discussionReading through Beads author's blog reveals him to be a person with decades of experience. To me it appears that Beads is a well thought out attempt to address the multitude of issues that the author has experienced over the years. NASA lost the Mars Climate Orbiter due to a confusion of values being in feet or meters. https://www.simscale.com/blog/2017/12/nasa-mars-climate-orbi... That is exactly the sort of mistak…
Comment linking /blog/2017/12/nasa-mars-climate-orbiter-metric/
on “Beads: Computer language and toolchain”Submitted Why the Future of Product Design Is in the Cloud as a story · 1 points
HN discussionSo many things are "Typed" but don't appear to be. 3PM (time zone). "Hello" (UTF-8/ASCII). 38.8977,77.0365 (WGS84). It's effectively the "NASA Mars Metric" mistake all over the place: https://www.simscale.com/blog/nasa-mars-climate-orbiter-metr...
Comment linking /blog/nasa-mars-climate-orbiter-metric/
on “You thought OpenStreetMap uses WGS84? No it doesn't (2019)”Submitted How to Convince Your Manager to Adopt Simulation Software as a story · 1 points
HN discussionThere's a surprising amount of corner cutting that goes on with large engineering projects. Examples: - A water slide had basic design flaws. That water slide would later go on to decapitate the son of a Congressman [1]; - The Millenium Tower in San Francisco was allowed to be built without the piles going down to bedrock [2]; - A borrowed system from an earlier rocket was never tested on the Ariane 5. An integer ov…
Comment linking /blog/space-shuttle-challenger-disaster/
on “Missing Titanic Sub Faced Lawsuit over Depths It Could Safely Travel To”Submitted SimScale – Senior Software Test Automation Engineer (m/f) in Munich/Germany as a story · 1 points
HN discussionMaybe not NASA, but what about its contractors? https://www.simscale.com/blog/nasa-mars-climate-orbiter-metr...
Comment linking /blog/nasa-mars-climate-orbiter-metric/
on “Pirates of the Caribbean (Metric Edition)”Submitted SimScale - Technical Lead/Senior Java Front End Developer (m/f) in Germany as a story · 1 points
HN discussionThe sad part is that this isn't the last time. https://www.simscale.com/blog/nasa-mars-climate-orbiter-metr...
Comment linking /blog/nasa-mars-climate-orbiter-metric/
on “40 years ago yesterday Air Canada Flight 143 ran out of fuel mid-flight”Thanks for the clarification! This makes sense. I do wonder who is liable if the software used to design a bridge outputs incorrect simulation results and the bridge collapses as a consequence. I suppose it's on the senior project engineer (or whoever ultimately signs off on the design) to verify the results somehow. Edit: This article [0] talks about the "trust" placed in commercial and open-source CAD software by…
Comment linking /blog/open-source-software-cae/
on “Louis Rossmann: Autodesk turns lifetime licenses into subscriptions [video]”Then why not just officially ditch what is, at this point, a quirky anachronism at best, and a potentially really expensive source of mistakes [1] at worst? [1]: https://www.simscale.com/blog/nasa-mars-climate-orbiter-metr...
Comment linking /blog/nasa-mars-climate-orbiter-metric/
on “The time Bell Labs brought the Statue of Liberty under its roof (Literally)”
