News for hackers. Stuff that matters.

A comment on LightSail 2 Spacecraft Successfully Demonstrates Flight by Light. Parent comment

Re:LightSail 2 Spacecraft Successfully Demonstrates Flight b... by c3534l on Wednesday July 31, 2019 @08:44PM (#20580202)
Gravity is exponential, which makes lifting fuel off of Earth a losing strategy for long-distance travel. Anything that is fueled by something already in space seems incredibly promising.
[ Parent | on HN ]
Re:LightSail 2 Spacecraft Successfully Demonstrates Flight b... by yarg on Wednesday July 31, 2019 @08:59PM (#20580286)
Newton's approximation of gravitational force is: G = gMm/d^2

The variable here is d (the distance between the centres of mass) - gravity is inverse quadratic (https://en.wikipedia.org/wiki/Inverse-square_law), not exponential.

[ Parent | on HN ]
Re:LightSail 2 Spacecraft Successfully Demonstrates Flight b... by foota on Wednesday July 31, 2019 @10:21PM (#20580645)
I suspect they were referring to the tyranny of the rocket equation.
[ Parent | on HN ]