No, it’s not going to Mars. It’s going near Mars. He said it’ll be placed in “a precessing Earth-Mars elliptical orbit around the sun.” What he means by this is what’s sometimes called a Hohmann transfer orbit, an orbit around the Sun that takes it as close to the Sun as Earth and as far out as Mars. This is a low-energy orbit; that is, it takes the least amount of energy to put something in this orbit from Earth. That makes sense for a first flight.
Does anyone have an idea on what the inclination will be near launch for a Mars trip? Will that impact what viewing location would be better? Will Playalinda and/or the causeway be open for the FH launch?
Quote from: butterwaffle on 12/03/2017 01:49 amDoes anyone have an idea on what the inclination will be near launch for a Mars trip? Will that impact what viewing location would be better? Will Playalinda and/or the causeway be open for the FH launch?Expect Playalinda to be closed.
Quote from: MarekCyzio on 12/03/2017 12:31 pmQuote from: butterwaffle on 12/03/2017 01:49 amDoes anyone have an idea on what the inclination will be near launch for a Mars trip? Will that impact what viewing location would be better? Will Playalinda and/or the causeway be open for the FH launch?Expect Playalinda to be closed.Why? I thought it was approved to be open for all launches.
Layman question: in such a Hohmann transfer orbit (and when not terminated by Mars orbit insertion), is there a risk of the trajectory intersecting Earth at some point in the future? (Presumably not right on the first orbit, since Earth is no longer there, but at some common multiple of the Earth's and payload's orbital period, I imagine.)Edit: s/Hoffman/Hohmann/
Quote from: dodo on 12/03/2017 06:11 pmLayman question: in such a Hohmann transfer orbit (and when not terminated by Mars orbit insertion), is there a risk of the trajectory intersecting Earth at some point in the future? (Presumably not right on the first orbit, since Earth is no longer there, but at some common multiple of the Earth's and payload's orbital period, I imagine.)Edit: s/Hoffman/Hohmann/Yes, but it's also possible to be in an orbit that has an exact resonance with Earth and will not intersect Earth's position.
Follow up: are Mars and Earth in resonant orbits, like Jupiter's inner moons? (I don't think so.) If not, I reckon it may not be possible to compute an orbit that avoids BOTH Earth and Mars.
Under the assumption that there will be no system that is able to do any burns after the roadster has left earth's vincinity, wouldn't it be impossible for it to enter such a resonant non-earth-intersecting orbit?
Quote from: Ictogan on 12/03/2017 08:42 pmUnder the assumption that there will be no system that is able to do any burns after the roadster has left earth's vincinity, wouldn't it be impossible for it to enter such a resonant non-earth-intersecting orbit?Why? The final orbit is determined by the delta-V at Earth's departure, plus whatever change results from the close shave to Mars. (I imagine the shave won't be that close, if they have no way of fine-tuning the approach.)
Venus's 583.92-day interval between successive close approaches to Earth is equal to 5.001444 Venusian solar days, making approximately the same face visible from Earth at each close approach. Whether this relationship arose by chance or is the result of some kind of tidal locking with Earth is unknown.[14]
venus and earth are in a 3:2 resonance?
Quote from: dodo on 12/03/2017 06:34 pmFollow up: are Mars and Earth in resonant orbits, like Jupiter's inner moons? (I don't think so.) If not, I reckon it may not be possible to compute an orbit that avoids BOTH Earth and Mars.Think 3d, if you change the inclination slightly, it is possible to always have an apogee that is above, or below Mar's orbital plane, forever missing. Though I do think the perigee will always intersection with Earth's plane.
The typical dynamical lifetime of near Earth asteroids is on the order of a few 10 million years. Within that typical time frame, they either collide with the sun, a planet, or might even be ejected from the inner solar system.
Lifting the apoapse out of the inner solar system is a lot easier, and even that will take multiple fortuitous gravity encounters, most likely with earth.