Kutuluka

Kudula mpira mpaka ndipo amabwerera. Kuthamanga ndi kovuta kwambiri ndipo sichichita. Padziko lapansi, galimotoyo imayenda ndi liwiro la makilomita 11.2 pa mphindi, ndipo chifukwa chofikapo kumeneku n’chifukwa chake ma roketi amagwira ntchito mofulumira kwambiri.

Mofulumira kwambiri, ndipo chinthu chothamanga sichibwereranso.

Onani

Kudula mpira pamwamba ndi kuti amapita pansi. Kuthamanga kwamphamvu, kumapita pamwamba pakumva kugwa. Kodi pali liwiro mofulumira kuti sichidzabwereranso?

Ndizosavuta. Izi zimatchedwa kutuluka m’mphepete (kapena kutuluka velocity). Pitani mosasamala kanthu kuti mwamsanga, ndi chilichonse kulepheretsa inu pansi, ndipo gravity singathe kuchotsani.

World	Kutuluka m’mphepete mwa nyanja
Mwezi	2.4 km/s
Mars	5.0 km/s
Dziko	11.2 km/s
Jupiter	59.5 km/s
Sun	617.6 km/s

The Moon’s escape speed is less than a quarter of Earth’s. Izi ndi chifukwa chomwe mwezi ukhoza kukhala malo othandiza kuti ayambe zinthu ku space.

Panthawi ya chisanu, mwezi umawoneka ngati wowala. Sankhani kutalika kwa magalimoto pansi ndi pamwamba pa kutalika kwa magalimoto otuluka omwe amapezeka mu zolemba.

Kumvetsa

Kutuluka kumachitika pamene mphamvu ya kinetic ya thupi ndi yokwanira kuti ifike ku “kutentha” kwa gravity. Kukhazikitsa mphamvu ya kinetic yofanana ndi mphamvu zofunikira kuti zifike kumapeto:

½ v² = μ / r  ⇒  v_escape = √(2μ / r)

Kuyerekezera ndi kuzungulira kwa √(μ/r): kutuluka kwa mpweya nthawi zonse ndi √2 ≈ 1.414 nthawi ya kuzungulira kwa mpweya panthawi yomweyo.

Mafunso awiri ofunika:

1. Izi sizingakhudzidwe ndi kukula kwanu. Mchenga ndi ndege ya kunyanja amafuna kuthamanga mofananamo. (The spaceship amafuna zambiri * mphamvu *, kotero.)
2. Izi zimadalira komwe mumayamba. Kutalika, r ndi kwakukulu ndipo kutuluka ndikotheka. Kuchokera pa kutalika kwa geostationary orbit, kutuluka kwa dziko lapansi ndi pafupifupi 4.3 km / s.

Rockets never actually fire up to 11.2 km/s at the ground. Amayenda mozungulira m’mphepete mwake, ndipo mapiko ake amawoneka ngati amangoyenda. Kuwala kwa dzuwa ndi chofunikira kwambiri pakupanga zinthu zosapanga dzimbiri monga pulasitiki.

Woyang’anira

In terms of specific orbital energy ε = v²/2 − μ/r, escape means ε ≥ 0. Pamene ε = 0, njira ndi parabola ndipo kuthamanga kumayenda ku zero pa infinity. M’njira yofulumira kwambiri, njira ndi hyperbola ndipo chinthu chimasunga kuwala kwamphamvu kopitilira muyeso, kuwala kwakukulu v∞:

v² = v∞² + v_escape²,   C₃ = v∞²

Mission planners quote launch energy as C₃ (km²/s²). For a Mars transfer, v∞ at departure is about 2.9 km/s, so C₃ ≈ 8.7 km²/s².

Izi ubale amachititsa imodzi mwa zotsatira zothandiza kwambiri mu spaceflight, Oberth zotsatira: kuwononga kopangidwa m’mphepete mwa gravity, komwe mumayenda mwachangu, kumagula zambiri v∞ kuposa kuwononga kofanana komwe kumachitika mozungulira. Kuchokera pa 200 km parking orbit kuzungulira dziko (kuzungulira kwa 7.78 km / s, kuthamanga kwa 11.0 km / s), kufika v∞ = 2.9 km / s kumafunikira maola 3.6 km / s a injini yowononga, osati 3.2 + 2.9 = 6.1 km / s. Ma satellite a ESA amagwiritsa ntchito njirayi poyang’anira ma orbits awo.