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Clarke's novel "Imperial Earth" features an "asymptotic drive", which utilises a microscopic black hole and hydrogen propellant, to achieve a similar acceleration travelling from Titan to Earth. The UET and Hidden Worlds spaceships of F.M. Busby 's Rissa Kerguelen saga utilize a constant acceleration drive that can accelerate at 1 g or even a ...
The upper limit for crewed return to Earth from low Earth orbit (LEO) or lunar return is 10g. [68] For Martian atmospheric entry after long exposure to zero gravity, the upper limit is 4 g . [ 68 ] Peak dynamic pressure can also influence the selection of the outermost TPS material if spallation is an issue.
Since, within the Roche limit, tidal forces overwhelm the gravitational forces that might otherwise hold the satellite together, no satellite can gravitationally coalesce out of smaller particles within that limit. Indeed, almost all known planetary rings are located within their Roche limit. (Notable exceptions are Saturn's E-Ring and Phoebe ring.
Earth may have had a ring made up of a broken asteroid over 400 million years ago, a study finds. The Saturn-like feature could explain a climate shift at the time.
Set in the Cold War, the story is based on the use of (relatively inexpensive) information-based "intelligent" systems to overcome an enemy's numerical advantage. The orbital kinetic bombardment system is used first to destroy the Soviet tank armies that have invaded Europe and then to take out Soviet ICBM silos prior to a nuclear strike.
MAVEN, a Mars-bound spacecraft, was launched into a trajectory with a characteristic energy of 12.2 km 2 /s 2 with respect to the Earth. [4] When simplified to a two-body problem , this would mean the MAVEN escaped Earth on a hyperbolic trajectory slowly decreasing its speed towards 12.2 km/s = 3.5 km/s {\displaystyle {\sqrt {12.2}}{\text{ km/s ...
Atmospheric escape of hydrogen on Earth is due to charge exchange escape (~60–90%), Jeans escape (~10–40%), and polar wind escape (~10–15%), currently losing about 3 kg/s of hydrogen. [1] The Earth additionally loses approximately 50 g/s of helium primarily through polar wind escape. Escape of other atmospheric constituents is much ...
In astronomy, perturbation is the complex motion of a massive body subjected to forces other than the gravitational attraction of a single other massive body. [1] The other forces can include a third (fourth, fifth, etc.) body, resistance, as from an atmosphere, and the off-center attraction of an oblate or otherwise misshapen body.