NASA units

 

Today is the anniversary of the day NASA lost a $125 million spacecraft to a unit conversion.

Mars Climate Orbiter disappeared because one engineering team worked in imperial units while another worked in metric.

Somewhere, Dr Foy is still saying: “Units and dimensions, class…”

Dr Foy was my physics teacher and, as a child, my role model. Elegant, brilliant and prone to regaling us with stories from her PhD days.

I went on to study physics at university, before evolving into a chemical engineer via biochemistry and, eventually, a PhD of my own.

(See what I did there? No? Never mind. It amused me.)

The right role model can change the trajectory of a student. A great mentor can do the same for someone at the beginning of their career.

And apparently, some lessons have a remarkably long shelf life.

Units matter.

Those who have worked for me or been unfortunate enough to be mentored by me will scarcely believe I’m still banging on about this.

But I see it constantly.

Brilliant people. Brilliant engineering. Brilliant calculations.

And somewhere along the way, mm has quietly become m, litres become cubic metres, or someone has wandered into the wrong unit system entirely.

The maths can be flawless.

The answer can still be catastrophically wrong.

Check your units.

Dr Foy taught me that.

NASA taught the rest of us why it matters. 🚀

——-

Today is the anniversary of NASA losing a $125 million spacecraft because two engineering teams disagreed about units.

One used imperial.

One used metric.

Mars, presumably, watched the whole thing and thought: You people are adorable.

This is why I bang on about units.

My childhood role model was Dr Foy, my physics teacher. Elegant, brilliant, and capable of making stories about her PhD days sound like the most exciting adventures imaginable.

She also taught us units and dimensions.

I went on to study physics at university, then somehow evolved into a chemical engineer via biochemistry and a PhD of my own.

So, really, this is all Dr Foy's fault.

The right role model can change the trajectory of a student.

A great mentor can do the same for an early career.

And apparently, some lessons have a remarkably long shelf life.

Those who have worked for me or been mentored by me will scarcely believe that I am still banging on about units.

But I keep seeing it.

Brilliant people. Excellent engineering. Beautiful calculations.

And somewhere in the process, mm quietly becomes m, litres become cubic metres, or somebody wanders into Imperial territory without a map.

The arithmetic can be absolutely impeccable.

The answer can still be spectacularly wrong.

Check your units.

Dr Foy taught me that.

NASA taught the rest of us why it matters. 🚀

Today is the anniversary of the day NASA lost a $125 million spacecraft to a unit conversion.

Mars Climate Orbiter disappeared because one engineering team worked in imperial units while another worked in metric.

Somewhere, Dr Foy is still saying: “Units and dimensions, class…” Dr Foy was my physics teacher and, as a child, my role model. Elegant, brilliant and prone to regaling us with stories from her PhD days.

I went on to study physics at university, before evolving into a chemical engineer via biochemistry and, eventually, a PhD of my own.(See what I did there? No? Never mind. It amused me.)

A role model can change the trajectory of a student and a great mentor can do the same for someone at the beginning of their career. And apparently, some lessons have a remarkably long shelf life: Units matter.

Those who have worked for me or been unfortunate enough to be mentored by me will scarcely believe I’m still banging on about this; Brilliant people. Brilliant engineering. Brilliant calculations.

And somewhere along the way, mm has quietly become m, litres become cubic metres, or someone has wandered into the wrong unit system entirely.

The maths can be flawless yet the answer can still be catastrophically wrong.

Check your units - Dr Foy taught me that.

NASA taught the rest of us why it matters. 🚀