[gibibit]

"A single 1-kW jammer can take down GPS for a 300-nm radius.[...] A CRPA can shrink the effective radius of the 1-kW jammer to 3 nm. The jammer’s area of effectiveness is slashed from 280,000 m² to 28 m²."

An example of the kind of unit confusion that could crash a Mars orbiter?

I thought we were talking about nanometers and square meters here for a second. But this only makes sense if "m²" means square miles and "nm" means nautical miles. How about at least using "mi" for miles to reduce confusion?

[lbourdages]

Well, nautical miles are the standard unit in the context of aviation, so I don't think it's all that bad. "mi" refers to a different unit.

[gibibit]

True, "nm" initially seemed to be nautical miles, but then this square meters thing appeared. The point is that "m" should be meters, but "mi" would be a more customary abbreviation for miles in the U.S.

[lupusreal]

They shouldn't have switched from nautical miles to miles. The area should have been expressed in square nautical miles.

[out_of_protocol]

mile and nautical mile are not the same so it still doesn't make any sense

[SAI_Peregrinus]

Agreed, though there's a space between the number & the unit which generally indicates non-SI units (SI should never have a space). The switch from nautical to statute miles is still really weird though.

[fenced_load]

Are you sure? NIST says there should be a space:

> There is a space between the numerical value and unit symbol, even when the value is used in an adjectival sense, except in the case of superscript units for plane angle.

https://physics.nist.gov/cuu/Units/checklist.html

[Propelloni]

> SI should never have a space

You are mistaken. SI units and their numbers always have a space. For reference [1], [2].

[1] https://www.npl.co.uk/si-units cf. Numerical Notation

[2] https://physics.nist.gov/cuu/Units/checklist.html cf. #15

EDIT: Scooped ;)

[ak1ng]

That's nonsense. There is a space between the number and the unit in SI.

[dpifke]

From https://news.ycombinator.com/newsguidelines.html:

Please don't complain about tangential annoyances—e.g. article or website formats, name collisions, or back-button breakage. They're too common to be interesting.