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NASA Signs Off on SpaceX's “Load-and-Go” Procedure for Crew Launches

posted by chromas on Monday August 13 2018, @04:00PM   Printer-friendly

Fnord666 writes:

The NASA manager overseeing development of Boeing and SpaceX's commercial crew ferry ships says the space agency has approved SpaceX's proposal to strap in astronauts atop Falcon 9 rockets, then fuel the launchers in the final hour of the countdown as the company does for its uncrewed missions.

The "load-and-go" procedure has become standard for SpaceX's satellite launches, in which an automatic countdown sequencer commands chilled kerosene and cryogenic liquid oxygen to flow into the Falcon 9 rocket in the final minutes before liftoff.

[...] SpaceX's "load-and-go" procedure raised concerns after a Falcon 9 rocket exploded on its launch pad at Cape Canaveral in September 2016. The fiery accident occurred in the final minutes of a countdown while propellants were flowing into the rocket before a hold-down engine firing, destroying the launcher and an Israeli-owned communications satellite on-board.

Officials from SpaceX said the Crew Dragon's escape system, comprising a set of high-thrust SuperDraco engines around the circumference of the capsule, would be quick enough to push the spacecraft and its crew away from such an explosion during fueling.

The abort thrusters will be activated and armed before fueling of the Falcon 9 during crewed launches.

SpaceX plans an unmanned, in-flight abort test prior to the first crewed flight, which is tentatively scheduled for April 2019.

Source: https://spaceflightnow.com/2018/08/09/nasa-signs-off-on-spacexs-load-and-go-procedure-for-crew-launches/

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  • (Score: 1) by Sulla on Monday August 13 2018, @05:18PM

    by Sulla (5173) on Monday August 13 2018, @05:18PM (#721052) Journal

    Here is a pad explosion of the Falcon 9.
    https://www.youtube.com/watch?v=_BgJEXQkjNQ [youtube.com]

    1:11 - Explosion begins
    1:20 - Payload falls from top of rocket
    1:23 - You can see the payload, based on the light around it there does not look to be any punctures

    So if you have the escape system primed to go and the computers sense a breach between 1:11 and 1:20 the DCM should be able to survive. Now.. I don't know how long it takes for those DCM engines to kick in.

    From wikipedia

    On 6 May 2015, SpaceX completed a pad abort test for the Dragon 2.[76][77][78][79] During this test, the Dragon used its abort engines to launch away from a test stand at Launch Complex 40.[76][77][79] It traveled to an altitude of 1,187 meters (3,894 ft),[80] separated from its trunk, deployed its drogue parachutes and then the main parachutes.[77][79] It splashed down into the ocean and was recovered.[77][79] The vehicle was planned to reach an altitude of 1,500 meters (5,000 ft) but one of the engines underperformed due to an abnormal fuel mixture ratio.[77][78] The Dragon flown is planned to be refurbished for the in-flight abort test.[78][79]

    In a planned in-flight abort test, Dragon will use its launch abort engines to escape from a modified Falcon 9 that is already in flight.[81][82] The launch is planned to occur from SLC-4E.[79] This test will occur at the point of worst-case dynamic loads, which is also when Dragon has the smallest performance margin for separation from its launch vehicle.[81] The Falcon 9 planned to be used will only have three engines on the first stage and will have no second stage.[79]

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