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Start with the free Future of AI course—2 hours, no technical background needed, completely free. You can begin understanding AI and how it relates to you today: https://bluedot.org/minutephysics
This video continues our tour of counter-intuitive space navigation weirdness, this time looking at the surprising capabilities of the bi-elliptic transfer - and how the further you travel, the more fuel you save!
- Two Paradoxes of Space Navigation: https://youtu.be/dLtRtdg67PU
- Hitting the Sun is HARD: https://youtu.be/LHvR1fRTW8g
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Minute Physics provides an energetic and entertaining view of old and new problems in physics -- all in a minute!
Created by Henry Reich
Produced by Joshua Chawner
00:00 Intro
00:23 The Worst Orbit
02:42 Bi-elliptic is Better
05:15 Travel Further With Less Fuel
06:31 Sponsor Message
Start with the free Future of AI course—2 hours, no technical background needed, completely free. You can begin understanding AI and how it relates to you today: https://bluedot.org/minutephysics
So Buzz Lightyear going to Infinity and beyond is just a cost savings measure.
This feels like it will be so useful the next time I play Kerbal Space Program, assuming I don't forget all of it
A bi-elliptic transfer shines when you’re trying to do a plane change. Can get up to 59% savings!
These videos are making me realize just how much Scott Manley and Kerbal Space Program have taught me and made intuitive.
theres another problem - when you go so far out you must be extremely precise on how much of a burn you do, so at these insane distances of overshooting thousands of times farther you must be very precise, or you will end up needing to make a course-correcting burn, and at the millions of times overshooting its simply impossible to be so precise so you will be needing to make a course-correcting burn
You just saved me from a huge mistake. Thank you, adjusting course now.
man i gotta go play Kerbal space program again this is huge
Two approximations in this video: First, the graphs use Δv as the cost, which is definitely not the same as fuel. In fact, a small saving in Δv can result in a huge saving in fuel. Second, an infinite bi-elliptic transfer is, technically, a bi-parabolic transfer.
I imagine if you tried to overshoot by an infinite amount, you'd reach a point where you are so far away that the gravity of the object you are orbiting can't pull you back faster than the universe is expanding. So there must be some finite limit imposed by the fact that the universe is expanding.
6:30 - There are also other mass out there, so if you go too far out, your elliptical orbits might have its trajectory altered by the gravity well of some other astronomical object and cause you to never reach the theoretical recircularization point. Even if you're overshooting by a large-but-finite distance.
2:52 I have actually used this in KSP before lmao. Just barely didn't have enough fuel to return to kerbin, so I ejected myself slightly further out and came back with 12m/s to spare.
The other problem with bi-elliptical transfers (and going to infinity) is that eventually you're going to hit the gravity well of another body and that'll screw up all your planning.
At a major axis ratio of 1:15, you're already well in the territory where a double-elliptic transfer is more efficient. The reason is actually exactly what was described in this video.
So when Buzz Lightyear insists on going "To Infinity and Beyond!" he's being fuel-conscious about an infinite bi-eliptic transfer.
4:25, I just love circulizing orbits
3:12 someone said time is money, but we say time is relative
There's also the fact that if you swing your orbit out far enough, you'll eventually find a second gravitation well you can swing off of for even more fuel savings.
Since you are on the orbital mechanics kick, please cover gravity assists.
Fun fact; modern moon missions overshoot towards the sun, and use the sun's gravity to extend their periapsis, they use the moon's gravity to catch them into an orbit around the moon, causing the whole mission to only cost the initial exit burn