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This is so cool, I didn‘t know about these yet and I‘d call myself a space buff... Speaking of flight and picking the nits here — looks like Wikipedia also isn
by endymi0n 6y ago
This is so cool, I didn‘t know about these yet and I‘d call myself a space buff...
Speaking of flight and picking the nits here — looks like Wikipedia also isn‘t completely correct here:
> It is planned to make the first powered flight on any planet beyond Earth
...arguably the first _powered_ flights were done by the sky cranes of Opportunity and Perseverance
- svachalek 6y agoIt seems that rocket propulsion does not count as “powered flight”
- alpaca128 6y ago> ...arguably the first _powered_ flights were done by the sky cranes of Opportunity and Perseverance Not the Apollo 11 lunar module? In contrast to the sky cranes it actually lifted off again.
- m4rtink 6y agoOn Mars the Viking probes used rockets for controlled landing, so that likely also counts. Pathfinder just had one shot braking rockets.
- dal 6y agoThe moon is not a planet.
- rriepe 6y agoI'd argue Mars is still the most impressive. Rockets in no atmosphere is easy. Floating on Venus is easy because it has more atmo than any other rocky planet. Figuring out something that works well in Mars' thin (but still there) atmosphere, especially a helicopter, is really impressive. The celestial body classification is just a cherry on top.
- dotancohen 6y agoBy many definitions the Earth-Moon system is a dual planetary system. The moon has more that 1% the mass of the Earth, which is by far the largest primary-secondary "not a planet" system in the solar system. Only not-a-planet Pluto and Charon exceed it. Also, Isaac Asimov considered the system a dual-planet system as the Moon's path around the sun is at no point convex nor retrograde.
- jojobas 6y agoEarth-Moon centre of mass is inside Earth, so, it's obvious that the Moon is orbiting the Earth, not both orbiting something else. 1% is an arbitrary threshold and solar orbit is dependent on external circumstances rather than the Earth-Moon system itself.
- dotancohen 6y ago> Earth-Moon centre of mass is inside Earth, so, it's > obvious that the Moon is orbiting the Earth, not both > orbiting something else. I used to agree with that school of thought, until I came up with a small thought experiment. Consider two bodies that are right on the planet-moon / dual-planet definition threshold. Intuitively, increasing the orbital distance between them would push them in the direction of which definition: planet-moon or dual-planet? I'd tend to say that separating them further would tend more towards planet-moon. Yet doing so moves the system's center of mass outside the larger body, so would actually push the system into the dual-planet definition by that criterion.
- shawnz 6y agoThe barycentre being inside of one of the things in the system is also an arbitrary threshold, isn't it? The barycentre of the Sun and Jupiter isn't inside of the Sun.. so does that mean Jupiter doesn't orbit the Sun?
- trailbits 6y agoIt's a fun exercise to work out the Gravitational Force between the Moon and the Earth and between the Moon and our Sun. It will surprise many that the Sun exerts more force on the Moon than the Earth does. So the Earth inflicts a strong perturbation on the motion of the Moon but it's not the dominant gravitational force on the Moon.
- tempestn 6y agoTechnically the moon is a dwarf planet, as it has sufficient gravity to form itself into a spheroid shape, but it has not cleared its orbit.
- Daho0n 6y agoIt's Pluto all over again!
- m4rtink 6y agoOn the Moon the first controlled powered flights were likely the Surveyor and Luna probes - they had braking and landing thrusters controlled by onboard avionics.
- SideburnsOfDoom 6y agoPowered? definitely. But Flight? A rocket has no fixed or rotating wing providing lift, so maybe not.