Post by Roberto Deboni DMIsrPrimo lancio di un Falcon 9 in orbita equatoriale circolare
http://youtu.be/CpmHsN5GUn8
minuto 52'18"
Zero gradi di inclinazione.
Velocita' circolare: 25'377 km/h / 25'378 km/h
La separazione accelera il secondo stadio di colpo
a 25'379 km/h.
Esercizio: nota la massa del secondo stadio e la menzionata
variazione di velocita', quale e' la massa del satellite ?
Durata missione 2 anni.
L'orbita non e' geosincrona, quindi il satellite si muove
rispetto ad un osservatore fisso all'equatore.
Trivia e cross-post:
On Thursday, December 9 at 1:00 a.m. EST, Falcon 9 launched
NASA’s Imaging X-ray Polarimetry Explorer (IXPE) to low Earth
orbit from historic Launch Complex 39A (LC-39A) at NASA’s
Kennedy Space Center in Florida. This was the fifth flight
for NASA’s Launch Service Program.
E' partito alle ore 7:00 italiane (GMT+1, essendo UCT=GMT).
This was the fifth flight for this Falcon 9’s first stage
booster, which previously supported launch of Crew-1, Crew-2,
SXM-8, and CRS-23.
This mission marked SpaceX’s 130th flight of Falcon 9 and its
90th successful landing.
Il piu' piccolo carico sollevata, ma:
<https://www.teslarati.com/spacex-nasa-ixpe-falcon-9-pad-39a-rollout/amp/>
"As noted, IXPE will weigh about a third of a ton at launch.
SpaceX’s Falcon 9, on the other hand, will weigh roughly 550 tons
(1.2M lb) when it lifts off, resulting in a truly unusual
payload ratio of approximately 1:1700 or 0.06%. However,
Falcon 9 will still have to work extremely hard to get IXPE
into the correct orbit. That’s because IXPE is designed to
operate in an almost exactly equatorial orbit with a zero-degree
inclination."
"Launching out of Cape Canaveral, which is located 28.5 degrees
above the true equator, it’s physically to launch directly into
a 0.2-degree equatorial orbit. Instead, a rocket needs to launch
into a due-East parking orbit and then perform what’s known as
a plane or inclination change once in space. Plane changes are
infamous for often being (in terms of rocket performance) one
of the most expensive maneuvers one can perform in orbit.
That’s certainly the case for IXPE, which will require a
28.5-degree plane change shortly after liftoff."
Per questo, e' piu' facile lanciare in orbita equatoriale
partendo dalla base spaziale di Kourou usata da ESA, dato
che si trova a solo 5 gradi latitudine nord (quindi ci sono
23,5 gradi in meno di correzione orbitale richiesta).