Kudzoka kumba: reentry

Nekuti munhu wese anoenda kunyika nendege anobva adzokera kumba nenzira imwecheteyo: nekushandura simba remhepo kuita magetsi. A capsule achisvika kubva orbit inotakura simba rakakwana pa kilogram kuti kutonhora yake pachayo upamhi musimbi nguva dzakawanda pamusoro. Chigadzirwa chekudzokera kunzvimbo chakanaka ndechekuti unowana simba rako richibva pasi, uye uchizvishandisa zvakaomarara kuti urambe uchirarama.

Mamwe marudzi emoto anotanga kupisa. Iyo mhepo inoita kuvhara.

Ona

1. The deorbit burn. Kuenda kumashure, capsule inotora injini yayo yemazuva mashoma uye inononoka ne100 m / s. Izvi zvinodzikisa pedyo nechimiro cheobiti ichienda mumhepo.
2. Entry interface, about 120 km up. The capsule meets the first thin traces of air still moving at about 7.8 km/s.
3. The fireball. Air pamberi pekupisa shiri inonzi yakasviba zvikuru uye inoshandurwa kuita glowing plasma, mamiriyoni emakore akaoma. Masimba eRadio haazovepo kwemazuva mashoma. Iyo tembiricha shiri inotonhora uye inoparadza, ichitakura mhepo neye.
4. The corridor. Kudzoka kubva paMweya pa11 km / s, iyo yekupinda angle inofanira kunge iri pedyo nechikamu chedhigirii: yakakwira kwazvo uye kuderera kunoparadza vafambi, yakadzika kwazvo uye capsule inobuda mumhepo sechidimbu chemvura.
5. Parachutes. Pamusoro pe10 km, capsule iri kukwira nechikepe ichi pamakore mashoma nemazana ekm/h. Parachutes open, uye inosvika pamakore mashoma emita per second.

_Zvinyorwa

Kubva pa400 km yemugwagwa wepasi (r = 6,778 km) iyo speed i 7.67 km/s. Ellipse iyo yakaderera peji iri 50 km pamusoro ine a = 6,603 km, uye pa400 km yayo speed inofanira kunge 7.57 km / s. Deorbit burn ndiyo iyo difference: about 102 m/s, chete 1.3% yesimba reorbital.

Drag force is ½ ρ v² C_D A. Air density ρ roughly halves every 5 km of descent (scale height about 7.2 km), so the deceleration rises steeply, peaks, and falls as the capsule slows. Mumufananidzo uri pamusoro:

Kupinda	_Speed:	Angle	Peak deceleration
Kubva pa low orbit	7.85 km/s	1.5°	nezve 8 g
Kubva pazuva, kusvikira kumashure	11 km/s	8°	nezve 31 g
Kubva pazuva, mukoridori	11 km/s	5.6°	nezve 7 g
Kubva pazuva, kushoma kwazvo	11 km/s	4.8°	bvisa

Real capsules kutakura nechimwe lift (vacho chinzvimbo chemafuta iri off-center, saka vanobva kutendeuka) uye roll kuti fambisa, izvo anoderedza peak kusvika pamusoro 4 g yeSoyuz uye akawedzera Apollo’s corridor kusvika pamusoro 2 degrees.

Munyori

Iyo model inobatanidza equations ye planar yekufamba ne gravity uye kudhonza chete:

dv/dt = −μ r/|r|³ − (ρ(h) |v| / 2β) v,   ρ(h) = ρ₀ e^(−h/H)

ne β = m/(C_D A) = 350 kg/m² (sekapsuli) uye H = 7,2 km. Kune yakakwira ballistic entrance, Allen neEggers (1958) vakaratidza kuti peak deceleration yakafanana neβ:

a_max ≈ v_E² sin γ / (2 e H)

For the steep lunar case (γ = 8°) it gives about 44 g; the full simulation gives 31 g, because gravity keeps bending the path shallower as the capsule descends. Kana kuti, kuwedzera angle, kwete chimiro chechitima, inogadzirisa g-kutakura, iyo ndiyo imwe yezvikonzero nei chero ndege yekudzoka ichifamba nenzvimbo yakajeka.