It's a lot more than you might think, and I couldn't find a comprehensive list of the non-spacecraft objects, some of which are hinted at in the first paragraph.
The later Apollo missions (13-17) deliberately crashed their 3rd stages into the moon, in part to provide a signal for the seismometer packages left at each of the landing sites. They hit the moon a little faster than the Falcon 9 2nd stage will hit (2.6km/s vs 2.43km/s for the new one).
What I think is very ironic is that Blue Origin actually beat SpaceX to Mars, after a decade of SpaceX "make life multiplanetary". A few months after Blue Origin did that SpaceX announced now they'll just go to the Moon, no more Mars.
That's not irony, that's shallow thinking. If you want to "make life multiplanetary" you would do it by building a very large, reusable, refillable rocket that can land 100 tons on Mars.
Which is exactly what SpaceX is doing.
[p.s.: The drive to land on the moon makes sense in the context of "how can we fund colonizing Mars?" Starlink funded the initial development of Starship. Musk believes (rightly or wrongly) that data centers in orbit and on the moon can fund the next set of projects.]
Several times the speed of sound? That is meaningless when there is no media for the sound waves.
I think a better unit might be furlongs per fortnight.
> 2.43 kilometers a second, or 1.51 miles a second, or 5,400 miles an hour, or 8,700 kilometers an hour.
> There is, of course, no air and no sound on the Moon, so a "Mach number" doesn't really make sense. But if there were air, the speed would be about Mach 7, seven times the speed of sound.
"If there were air". Air at which temperature though? Th sound of speed, and hence what Mach numbers mean, depends on the temperature of the air. The temperature air would have at the moon's surface? By day or by night? Or the air at Earth's surface? Or at some other altitude?
Well, there is a speed of sound on the moon. Sound does travel through the regolith. If you were standing on the moon you would indeed "hear" this impact as the sound moved up through your feet. It would sound/feel like standing beside a subwoofer.
https://en.wikipedia.org/wiki/List_of_artificial_objects_on_...
It's a lot more than you might think, and I couldn't find a comprehensive list of the non-spacecraft objects, some of which are hinted at in the first paragraph.
All of those impact sites have been located but the last one wasn't pinpointed until 2016: https://www.cbsnews.com/news/moon-mystery-solved-apollo-rock...
ref: https://books.google.ie/books?id=6QAAAAAAMBAJ&pg=PA56&lpg=PA...
https://www.nasa.gov/news-release/nasa-blue-origin-launch-tw...
Falcon Heavy launched a spacecraft that used a Mars gravity assist in 2023 https://en.wikipedia.org/wiki/Psyche_(spacecraft) same with the Europa Clipper https://en.wikipedia.org/wiki/Europa_Clipper going to Jupiter
Which is exactly what SpaceX is doing.
[p.s.: The drive to land on the moon makes sense in the context of "how can we fund colonizing Mars?" Starlink funded the initial development of Starship. Musk believes (rightly or wrongly) that data centers in orbit and on the moon can fund the next set of projects.]
> 2.43 kilometers a second, or 1.51 miles a second, or 5,400 miles an hour, or 8,700 kilometers an hour.
> There is, of course, no air and no sound on the Moon, so a "Mach number" doesn't really make sense. But if there were air, the speed would be about Mach 7, seven times the speed of sound.