# How much accuracy is required to achieve interplanetary orbit without adjustment or deceleration?

It seem that "Around 15,000 tonnes of meteoroids, micrometeoroids and different forms of space dust enter Earth's atmosphere each year" some references say "Millions of meteors occur in the Earth's atmosphere daily." it would seem with millions of chances per day, a one in a million occurrence should occur at least once per day.

Answers at How much of the space debris around Earth is man-made? are suggesting that everything in orbit around the Earth (other than the Moon) is man made.

Ignoring inaccuracies in get from Earth to Space, if a ship is in space how accurate would a launch from space need to be to achieve an stable orbit around another planet that would last at least 1 year (longer is better)

• Answer givers choice of destination planet
• Assume all fuel is expended at initial launch (from space)
• No travel time constraints

There are 173 known natural satellites in our solar system, some of which are presumed to be captured, so achieving a moderately stable orbit without adjustment or deceleration should be theoretically possible.

Edit

Trying to clarify: Recent comments here and at the related question point out that the difficulties for a meteoroid to achieve orbit the Earth is related to the presence of the Moon. So using that example as part of my question complicated things unnecessarily.

Here is my train of thought: on an interplanetary journey where the drive system is off for most of the journey, any number of things could go wrong that would prevent the engine from being available at the destination planet. A solution is to have a predestined stable orbit on arrival.

If the trajectory at main engine shut down when leaving Earth is such that the ship will enter a stable orbit on arrival, a main engine failure is not catastrophic.

Is it possible to set an initial trajectory that will result in a stable orbit on arrival? Would solar winds or minor gravitational attractions make a stable orbit a mater of luck (or dependent on pre-calculations beyond our abilities)? Would the accuracy required at interplanetary distances be so tight that current technology would not allow for it?

• What is the definition of 'accuracy'? Is it up to the answerer? There are infinitely many launches that will get you into as many different orbits. Among these some will have more tolerance on say, the launch direction, than others, but they may be more susceptible on errors on ΔV. So how do we pick the reference perfect launch? – Mau Jun 3 '15 at 19:23
• If I'm not just having a bad day, I think the question could be clearer. What proportion of trajectories within a planet's sphere of influence result in a stable orbit? That's still clumsy, it doesn't address what speeds result in capture... and then there is the matter of the difference an atmosphere makes... The focus on a spacecraft makes the references to meteors a bit confusing, I'm thinking maybe put that at the end? And clarify you mean one in a million should enter a stable orbit? I like the question but I'm having all these thoughts... – kim holder Jun 3 '15 at 19:43
• Incidentally, I had the same thought about the space debris question, but shied away from commenting, figuring I was just wrong. If you don't mind, I'll take your impetus and now post that comment :P – kim holder Jun 3 '15 at 19:46
• If I understand the question correctly, the answer is hugely dependent on what else is around the target planet. Two-body situations are stable; either you're already in orbit or you will impact or you will not be captured. You need the gravity assist of another body to change your orbit relative to the target planet. A planet like Jupiter, with several massive moons relatively close in, offers a much larger chance of capture than does Venus, Mars, or Mercury. – Russell Borogove Jun 3 '15 at 20:11
• Edited to clarify. – James Jenkins Jun 4 '15 at 11:20