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When we're wandering around on Earth we naturally tend to think of the "closeness" of locations in terms of distance because of the way we travel here. But if

When we're wandering around on Earth we naturally tend to think of the "closeness" of locations in terms of distance because of the way we travel here. But if you're thinking of traveling to another planet you shouldn't be thinking of linear distance, you should be thinking of delta-v. And by that metric the planets form the same neat line you find in a classroom chart with Venus edging out Mars. https://www.reddit.com/r/space/comments/29cxi6/i_made_a_deltav_subway_map_of_the_solar_system/ https://www.reddit.com/r/space/comments/29cxi6/i_made_a_delt... Linear distance isn't entirely irrelevant. It affects light lag for instance. But it is mostly irrelevant.

agildehaus 7y ago
Delta-V at the time of optimal travel. Otherwise it's probably as all over the place as this video.
- TeMPOraL 7y ago
  Now I want to see porkchop plots for transfers to each planet stacked on top of each other, or otherwise presented together somehow.
- Retric 7y ago
  Only significant if you try and minimize travel times. Get out of earths orbit and waiting without burning fuel let’s you sync up.
sillysaurusx 7y ago
Does anyone know a simulation of the solar system corrected for delta-v? It would be neat to see visually how the planets compare. Like a 3D rendering, or a screensaver. You'd need to morph distance such that if a point takes less energy to travel to from earth, it appears either closer or larger. Bonus points if it accounts for time dilation somehow.
- GuB-42 7y ago
  Not exactly a simulation but it is a nice illustration, I think. https://xkcd.com/681/ https://xkcd.com/681/
- chrisweekly 7y ago
  Kerbal Space Program?
- fyfy18 7y ago
  There is a delta-v map (not to scale) of our solar system that could be used as the basis of this: https://www.reddit.com/r/space/comments/1ktjfi/deltav_map_of_the_solar_system/ https://www.reddit.com/r/space/comments/1ktjfi/deltav_map_of...
  - JetSpiegel 7y ago
    Direct link to the image: https://i.imgur.com/SqdzxzF.png https://i.imgur.com/SqdzxzF.png
  - throwaway2048 7y ago
    One of the more interesting consequences of orbital mechanics is it takes far more delta-v to get close to the sun, than it does to leave the solar system entirely. Think about this in terms of how fast the earth is moving to avoid "falling into" the sun, anything that leaves the earth has that velocity too.
    - DavidSJ 7y ago
      If you do a Hohmann transfer — the most basic sort, used by most Δv calculations — from Earth to the Sun, yes. But if you give yourself solar escape velocity (a savings of about 59% in your hyperbolic Earth escape velocity, which works out to a huge savings of about 18.9 km/s Δv if you do your burn in Low Earth Orbit), then once you get very far from the Sun you can stop yourself virtually for free, and fall straight down. The whole trip would take decades though. The same basic idea works for reaching any inner object orbiting any body. In practice you can probably do better by aiming for a planet and slingshotting, but that gets more complicated.
BurningFrog 7y ago
It's all about ping time, man!
SlowRobotAhead 7y ago
There are lots of astrology enthusiasts that would care much more about mostest closest than travel path. Also things like “lining up”. You can check with my Aunt Karen.
azernik 7y ago
Delta-V isn't the only consideration. Seeing as how humans need constant supply and environmental control, travel time for a reasonable dV budget is also important; e.g. with aerobraking it takes less dV to get to the Mars surface than to the Lunar surface, but the life support and (even for robotic missions) power/thermal systems need to be much more substantial.
mcv 7y ago
Delta-V to Venus and Mars is only that small when you launch at the correct time. Just as with linear distance, where are plenty of times when delta-V to get to Venus or Mars is going to be a lot larger. But Delta-V and linear distance are different things. This particular discussion of linear distance to other planets is extremely useful to demonstrate how biased our perception and understanding are. Because of the way we usually look at and discuss planets, everybody blindly assumes that Venus and Mars are closer in linear distance than Mercury, when in reality that's usually not the case. Checking our assumptions and perceptions like that is a useful exercise in itself, even when it's not directly relevant to rocket science.
deleted 7y ago
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agildehaus 7y ago

Delta-V at the time of optimal travel. Otherwise it's probably as all over the place as this video.

TeMPOraL 7y ago
Now I want to see porkchop plots for transfers to each planet stacked on top of each other, or otherwise presented together somehow.
Retric 7y ago
Only significant if you try and minimize travel times. Get out of earths orbit and waiting without burning fuel let’s you sync up.

sillysaurusx 7y ago

Does anyone know a simulation of the solar system corrected for delta-v? It would be neat to see visually how the planets compare. Like a 3D rendering, or a screensaver. You'd need to morph distance such that if a point takes less energy to travel to from earth, it appears either closer or larger. Bonus points if it accounts for time dilation somehow.

GuB-42 7y ago
Not exactly a simulation but it is a nice illustration, I think. https://xkcd.com/681/ https://xkcd.com/681/
chrisweekly 7y ago
Kerbal Space Program?
fyfy18 7y ago
There is a delta-v map (not to scale) of our solar system that could be used as the basis of this: https://www.reddit.com/r/space/comments/1ktjfi/deltav_map_of_the_solar_system/ https://www.reddit.com/r/space/comments/1ktjfi/deltav_map_of...
- JetSpiegel 7y ago
  Direct link to the image: https://i.imgur.com/SqdzxzF.png https://i.imgur.com/SqdzxzF.png
- throwaway2048 7y ago
  One of the more interesting consequences of orbital mechanics is it takes far more delta-v to get close to the sun, than it does to leave the solar system entirely. Think about this in terms of how fast the earth is moving to avoid "falling into" the sun, anything that leaves the earth has that velocity too.
  - DavidSJ 7y ago
    If you do a Hohmann transfer — the most basic sort, used by most Δv calculations — from Earth to the Sun, yes. But if you give yourself solar escape velocity (a savings of about 59% in your hyperbolic Earth escape velocity, which works out to a huge savings of about 18.9 km/s Δv if you do your burn in Low Earth Orbit), then once you get very far from the Sun you can stop yourself virtually for free, and fall straight down. The whole trip would take decades though. The same basic idea works for reaching any inner object orbiting any body. In practice you can probably do better by aiming for a planet and slingshotting, but that gets more complicated.

BurningFrog 7y ago

It's all about ping time, man!

SlowRobotAhead 7y ago

There are lots of astrology enthusiasts that would care much more about mostest closest than travel path. Also things like “lining up”. You can check with my Aunt Karen.

azernik 7y ago

Delta-V isn't the only consideration. Seeing as how humans need constant supply and environmental control, travel time for a reasonable dV budget is also important; e.g. with aerobraking it takes less dV to get to the Mars surface than to the Lunar surface, but the life support and (even for robotic missions) power/thermal systems need to be much more substantial.

mcv 7y ago

Delta-V to Venus and Mars is only that small when you launch at the correct time. Just as with linear distance, where are plenty of times when delta-V to get to Venus or Mars is going to be a lot larger. But Delta-V and linear distance are different things. This particular discussion of linear distance to other planets is extremely useful to demonstrate how biased our perception and understanding are. Because of the way we usually look at and discuss planets, everybody blindly assumes that Venus and Mars are closer in linear distance than Mercury, when in reality that's usually not the case. Checking our assumptions and perceptions like that is a useful exercise in itself, even when it's not directly relevant to rocket science.

deleted 7y ago

[deleted]