Space - Spacex, NASA, Rocket Lab

Snowy

I have now wondered, how do they measure altitude on Mars? No mean sea level, so this is the answer:

"Martian elevation values were obtained by subtracting the radius of the Mars areoid from the radius of Mars at each observation point. The resulting elevations were used to produce the topographic map."

Snowy

If anybody didn't understand "areoid", and I didn't, this is it:

Noun
areoid (plural areoids)
(astronomy, geology, planetology) The analogue of the geoid for the planet Mars; the Martian geoid. The gravitational and rotational equipotential surface for Mars. The surface that provides the datum line (the equivalent for sea level) for Mars.

I am delighted that should I ever get to fly on Mars I will at least understand the altitude that I won't run into Olympus Mons.

nzzp

@snowy elevation is hard on earth as well. General numbers are good, precision gets really really hard depending on the assumptions around the shape of the earth

Kiwiwomble

@nzzp yeah, there isn't one "sea level" when we give and elevation we have to reference it to specific vertical datum, a common one in chch was the Christchurch drainage datum which gave zero or sealavel as a distance below the floor of the cathedral. When compared with the more recent Lyttelton tide gauge, several meters apart...both commonly used "sea levels"

Snowy

@nzzp said in NASA:

@snowy elevation is hard on earth as well. General numbers are good, precision gets really really hard depending on the assumptions around the shape of the earth

Yeah. With flying around it isn't much of a deal because we have at least 1000ft leeway under IFR but I doubt these precise geometrics are an issue for exploring Mars at this point. Good fun though.

voodoo

@snowy said in NASA:

If anybody didn't understand "areoid", and I didn't, this is it:

Noun
areoid (plural areoids)
(astronomy, geology, planetology) The analogue of the geoid for the planet Mars; the Martian geoid. The gravitational and rotational equipotential surface for Mars. The surface that provides the datum line (the equivalent for sea level) for Mars.

I am delighted that should I ever get to fly on Mars I will at least understand the altitude that I won't run into Olympus Mons.

Sheesh, as if we didn't know that already 🙄

Snowy

@voodoo said in NASA:

Sheesh, as if we didn't know that already

Sorry about that, didn't mean to treat you all as morans because I wasn't sure what the Martian geoid was. Apologies again, I will attempt not to repeat the error, have given myself several upper cuts and will feel guilty for several...
well actually I'm O.K. now.