## Príspevky

### Pravdepodobnosť, že v skupine sa nachádzajú dve osoby s rovnakým dátumom narodenia

Mirek Rokyta otvoril tento  problém vo videu https://youtu.be/cuBbmeLwZGg Riešenie: Pm = 1-365!/365^x/(365-x)! pocet osôb v skupine pravdepodobnosť Pm 2 0,003 3 0,008 4 0,016 5 0,027 6 0,040 7 0,056 8 0,074 9 0,095 10 0,117 11 0,141 12 0,167 13 0,194 14 0,223 15 0,253 16 0,284 17 0,315 18 0,347 19 0,379 20 0,411 21 0,444 22 0,476 23 0,507 ... 75 0,9997

### Boeing CST-100 Starliner

On 22 December 2019 at 6:55 AM EST, Starliner was cleared to reenter the Earth's atmosphere.  A 55 second deorbit burn started at 7:23 AM EST. Service module separation occurred at 7:26 AM EST and entered Earth's atmosphere at 7:41 AM EST.   The heat shield jettisoned and the drogue-chutes deployed at 7:53 AM EST main parachutes deployed at 7:54 AM EST. [ citation needed ]  The Starliner touched-down at  White Sands Missile Range  successfully at 7:58:02 AM EST.

### Halo orbit

A halo orbit is a periodic, three-dimensional orbit near the L1, L2 or L3 Lagrange point in the three-body problem of orbital mechanics . Although the Lagrange point is just a point in empty space, its peculiar characteristic is that it can be orbited. Halo orbits can be thought of as resulting from an interaction between the gravitational pull of the two planetary bodies and the Coriolis and centrifugal accelerations on a spacecraft. Halo orbits exist in any three-body system, e.g., the Sun – Earth –Orbiting Satellite system or the Earth– Moon –Orbiting Satellite system. Continuous "families" of both Northern and Southern halo orbits exist at each Lagrange point. Because halo orbits tend to be unstable, stationkeeping is required to keep a satellite on the orbit. Most satellites in halo orbit serve scientific purposes, for example as space telescopes . https://en.wikipedia.org/wiki/Halo_orbit JWST trajectory and halo orbit Halo orbit around L2

### Nodal precession Precesia uzlov

Nodal precession  is the  precession  of the  orbital plane  of a  satellite  around the  rotational  axis of an  astronomical body  such as  Earth . Rate of precession The rate of precession depends on the  inclination  of the orbital plane to the equatorial plane, as well as the orbital eccentricity. For a satellite in a  prograde orbit  around Earth, the precession is westward (nodal regression), the node and satellite move in opposite directions. [1]  A good approximation of the precession rate is {\displaystyle \omega _{\mathrm {p} }=-{\frac {3}{2}}\cdot {\frac {{R_{\mathrm {E} }}^{2}}{\left(a\left(1-e^{2}\right)\right)^{2}}}J_{2}\omega \cos i} where ω p  is the precession rate (in  rad /s) R E  is the body's equatorial radius ( 6 378 137  m  for Earth) a  is the  semi-major axis  of the satellite's orbit e  is the eccentricity of the satellite's orbit ω  is the angular velocity of the satellite's motion (2 π  radians divided by its perio