Ukuya ekhaya: ukubuyela ngaphakathi

Wonke umqhubi wenqwelomoya ufika ekhaya ngendlela efanayo: ngokujika isantya sibe kubushushu. I-capsule efika kwi orbit ithatha amandla afanelekileyo nge kilogram ukutshisa ubunzima bayo bentsimbi amaxesha amaninzi ngaphezulu. Ubugcisa bonke bokungena kwakhona kukususa loo mandla ngokucothayo ngokwaneleyo ukuba uphile, kwaye ngokukhawuleza ngokwaneleyo ukuba ungabuyanga kwisithuba.

Iinjini ziqala ukuwa. Umoya usenza ukutshixa.

Bona

1. I-deorbit itshisa. Ibonisa ngasemva, i-capsule iqhuba i-injini yayo kwimizuzu emininzi kwaye ikhawuleza malunga ne-100 m/s. Eli nqanaba likhupha icala elifutshane le orbit yayo kwimozulu.
2. Indawo yokungena, malunga ne-120 km phezulu. Ikapsula idibana nokuqala okuncinci komoya ohamba malunga ne-7.8 km/s.
3. Ibhola yomlilo. Umoya phambi kwesikhuseli sobushushu ucinezelwe kakhulu ukuba ube yiplasma ekhanyayo, amawaka eeqondo ashushu. Iimpawu zesandi soqhagamshelwano azikwazi ukudlula kwimizuzu embalwa. Isikhuseli sobushushu sihamba ngokucothayo kwaye sityhapha, sithwala ubushushu kunye nalo.
4. Indlela yokungena. Ukubuyela ukusuka kwinyanga nge 11 km/s, i-engile yokungenisa kufuneka ibe phezulu ukuya kwinxalenye yeqondo: iphakamileyo kakhulu kwaye ukukhawuleza kuya kutyhala abaqhubi, iphantsi kakhulu kwaye i-capsule iyaphuma kumphunga njengelitye elinokususwa ngamanzi.
5. Iiparachutes. Ezantsi malunga ne-10 km ikapsula iwela kumawaka amabini e-km/h. Iiparachutes zivuliwe, kwaye iwela kwimitha embalwa ngesekondi.

Ukuqonda

Kwi-400 km ye-orbit ejikelezayo (r = 6,778 km) isantya siyi-7.67 km/s. I-ellipsis enendawo ephantsi eyi-50 km phezulu ine-a = 6,603 km, kwaye kwi-400 km isantya sayo kufuneka sibe yi-7.57 km/s. Umlilo wokususa i-orbit yinto eyahlukileyo: malunga 102 m/ s, kuphela i-1.3% yesantya sokuhamba kweplanethi.

Uxinzelelo lokutsala luyi ½ ρ v² C_D A. Uxinzelelo lwamanzi ρ lunyuka ngeepesenti nganye yeekhilomitha ezi-5 zokuhla (ubude bemitha malunga neekhilomitha ezili-7.2), ngoko ukucotha kukhupha ngokuthe nkqo, ifike kwinqanaba eliphezulu kwaye likhuphe njengoko ikapsula icotha. Kwimodeli engaphezulu:

Ungeniso	Isantya	I-Engile	Ukunciphisa okuphezulu
I-Orbit	7.85 km/s	1.5°	malunga ne-8 g
Inyanga	11 km/s	8°	malunga ne-31 g
Inyanga	11 km/s	5.6°	malunga ne-7 g
Inyanga	11 km/s	4.8°	ishiya phantsi

Real capsules fly with a little lift (their centre of mass is off-centre, so they fly tilted) and roll to steer it, which lowers the peak to about 4 g for a Soyuz and widened Apollo’s corridor to about 2 degrees.

Umphathi

Imodeli idibanisa ii-equations zeplanethi zokuhamba ngesantya somhlaba kunye nokutsala kuphela:

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

nge β = m/(C_D A) = 350 kg/m² (i-capsule-like) kunye ne H = 7.2 km. Ukungenisa i-ballistic ethe nkqo, uAllen noEggers (1958) babonisa ukuba ukukhawuleza okuphezulu kuxhomekeke kwi-β:

a_max ≈ v_E² sin γ / (2 e H)

Kwimeko yenyanga ethe nkqo (γ = 8°) inika malunga ne-44 g; ulinganiso olupheleleyo lunika i-31 g, kuba ukutsala komhlaba kuqhubeka nokwenza indlela ibe mfutshane njengoko ikapsula ihla. Nayiphi na indlela, i-engile yokungena, hayi ubungakanani besithuthi, imisela umthwalo we-g, oko kukuthi kutheni yonke inqanawa ebuyela kwihlabathi liphela ibaleka ngendawo efanelekileyo yokuqhuba.