https://www.nasaspaceflight.com/2021...ht-road-orbit/
SpaceX - The Route to Orbit
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As reported from recent documentation, SpaceX is targeting the flight of Super Heavy BN3 with Starship SN20 for the orbital test flight.
While the designated vehicles for the mission may change over the coming weeks, a sign the test flight is deep into the planning phase was observed
with the publication of a filing with the Federal Communications Commission (FCC).
According to the FCC overview, the flight profile calls for staging between the Super Heavy and Starship at approximately 170 seconds into flight…..
Super Heavy will have a full set of Raptors; the number has likely changed since the 2019 Starship update when Super Heavy was to have 28 engines. The outer ring of engines will not have Thrust Vector Control while the inner ones will. Starship is set to utilize six Raptors, three sea-level and vacuum-optimized. As such, this test flight alone will require a large stock of Raptor engines.
While Raptors arriving into Boca Chica are in the SN50 and SN60 range,
SpaceX’s test site in McGregor is hosting engines in the SN70-80 range, while it is understood that production in Hawthorne is working on engines past SN150 — with a current shipping rate of several Raptors per week.
To support a fully expendable launch with over 30 Raptors, SpaceX has drastically increased the Raptors’ production rate. Following the new clean Raptor design, SpaceX has increased production,
while McGregor is ready to cater to the increased test cadence with a new vertical engine test stand.
Demand for Raptors, not least with the first orbital test flight being expendable, will only increase as SpaceX pushes through to future missions with additional Super Heavy and Starship flights.
While the SN20 and BN3 combo will be first in line for orbital flight, it’s expected that the subsequent boosters and ships will pair up accordingly, SN21 with BN4, SN22 with BN5, and SN23 with BN6. In addition, it’s understood that a major design upgrade is set to come with the SN24/BN7 pair…..