Jun 17, 2014 Can you launch a projectile from the Earth such that it never comes back? Skip navigation. Escape speed and black holes. Orbits and Escape Velocity 8.01 Classical Mechanics, Fall.
According toat the Earth/Moon distance from the sun, the escape velocity is 42.1 km/s.According tothe average orbital speed of Earth is 29.78 km/s.The difference is 42.1 km/s - 29.78 km/s = 12.32 km/s.The escape velocity from Earth surface is about 11.2 km/s.The velocity in lowest Earth orbit is about 8 km/s. Take a delta-v of 9.5 km/s to become realistic.Hence an additional 11.2 km/s - 9.5 km/s = 1.7 km/s is needed to escape the gravitational field of the Earth.The sum of the two deltas is 1.7 km/s + 12.32 km/s = 14.02 km/s.To dive into the sun, from the orbital speed of 29.78 km/s of Earth the probe needs to be slowed down to zero.The gravity from lower Earth orbit has to be overcome by additional 1.7 km/s.Together 29.78 km/s + 1.7 km/s = 31.48 km/s.Are there fundamental errors (besides minor aphelion-perihelion discrepancies)?
If so, which ones? $begingroup$ There are some details I didn't understand: The 9.5 km/s contain the 8 km/s for a circular orbit on zero height plus the kinetic energy equivalent of the potential energy of the height of the orbit relative to the surface. How gets the air drag into these 9.5 km/s? Shouldn't on the gravitational potential of a lower earth orbit the escape velocity be below 11.2 km/s? How is the height of the low earth orbit considered in 'r=6,354.82 km'? Where do the 11.2 km/s come from in 16.65-11.2=2.26 km/s?
$endgroup$–Feb 6 '14 at 15:15. $begingroup$ @Gerald I need to be more precise when I'm talking about the physical sequence of events. What happens: (1) rocket blasts into orbit (2) while in this orbit, fires engines again, enough to get to destination.
That means that the burn is finished long before it gets out of the gravity well. You do it that way because of the Oberth effect. If you waited until you were away from Earth, then fired the 3rd Delta V, it would take more by the Oberth ratio I gave. 'extra burn needed past escape V' is the relative velocity after out of the gravity well.
But burn is done before leaving gravity well $endgroup$–Feb 6 '14 at 18:29. A different way to get to the sun is 9.5 km/s for getting to LEO, 3.5 km/s (less if you slingshot around moon) to escape to solar orbit, then 8.8 km/s for solar escape minus Jupiter/Saturn slingshot then before you escape burn retrograde till perisol is below solar surface. Total should be less than 21 km/s.Pluto's orbit is on average 10km/s so I'd guess 6-8 km/s.Sources: Wikipedia, other answers, and I play lots of Kerbal with RSS.Note: launch into a prograde orbit near equator, otherwise it takes 10 km/s to get to orbit.Note 2: use a fuel that does not evaporate over time.
Escape velocity, in astronomy and, the that is sufficient for a body to escape from a gravitational centre of attraction without undergoing any further. Escape velocity decreases with altitude and is equal to the of 2 (or about 1.414) times the velocity necessary to maintain a circular orbit at the same altitude.
At the surface of the, if atmospheric resistance could be disregarded, escape velocity would be about 11.2 km (6.96 miles) per second. The velocity of escape from the less massive is about 2.4 km per second at its surface.
A (or satellite) cannot long retain an atmosphere if the planet’s escape velocity is low enough to be near the average velocity of the gas molecules making up the atmosphere.
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