SpaceX resumes launches


    After a half-year break associated with the accident of the Falcon-9 launch vehicle (in the CRS-7 mission to service the ISS), SpaceX resumes flights. The start is scheduled for the window between 4.00 and 5.00 hours on December 20 Moscow time (the start was postponed to December 22 ). With this launch, 11 satellites of Orbcomm telecommunications company should be launched. The launch will be carried out using the new version of the launch vehicle - Falcon 9 v1.2 (according to other sources - the name Falcon 9 v1.1 Full Thrust).

    Orbcomm satellites, weighing 172 kilograms each, will be launched into a highly elliptical orbit:

    Work on the new version of the rocket was started before the accident, but after it SpaceX decided to check all the equipment used in the launch vehicle for certification, which greatly delayed the preparation. Falcon-9 v1.2 should replace the old version of Falcon 9 v 1.1 on an ongoing basis (another launch of v 1.1 is expected under the contract of NASA and NOAA). On September 21, checks were made on an improved version of the first stage:

    In preparation for the upcoming flight, the first stage was delivered to the launch site on November 20, and by the end of November the second stage was also delivered. Static fire tests of the particular rocket that will fly will be held on December 16, three days before launch. Already, two more rockets (old and new versions) are being prepared for launches for launches in January, and the next flight to the ISS is preparing for February.

    The new version of the rocket provides an increase in thrust by 15%, tank capacity by 10% (due to the increase in fuel density, which is achieved by cooling liquid oxygen to lower temperatures). The same improvements are envisaged in the second stage. In general, the rocket "grew" by 1.5 meters, the launch weight increased from 506 to 541 tons. This allows landing not only according to the CRS program (Dragon flights to the ISS), which were carried out with significant "underload", but also in other flights.

    This flight involves landing the first stage on the ground (with the return of the rocket to the launch site), in contrast to previous attempts to land on the barge (hereinafter referred to as the rocket’s flight rate), at the moment it is reported that SpaceX has not yet managed to get permission to land, and it’s possible Landing tests will fail. It was also stated that after the removal of all satellites in the second stage, a significant part of the fuel will be saved, and after confirmation of the separation of the satellites, it is planned to conduct additional tests (attempts to return it from orbit have not yet been planned).

    About the progress of the investigation of the CRS-7 accident:
    On July 28, 2015, after a regular take-off, a sharp increase in pressure occurred in the Falcon 9 liquid oxygen tank, about 139 seconds of flight, which resulted in an accident. This is a preliminary assessment, further investigation will show more.
    Before the accident, the first stage of the rocket, including all nine Merlin 1D engines, worked normally, the first stage continued its normal operation for a few seconds after the pressure surge. The Dragon ship survived during the accident, and continued to transmit information until it disappeared over the horizon.

    SpaceX is conducting an investigation under the supervision of the Federal Aviation Agency, with the participation of NASA and the United States Air Force. The collection of flight data was not easy, both because of the large amount of data - 3000 telemetric channels, video viewing and inspection of debris, and because of the rapidly developing accident process.

    Only 0.893 seconds passed from the first indication to the loss of all telemetry. The last few weeks (the report was published on July 25 - approx. Transl.), The team of engineers spent thousands of hours in the process of meticulous data processing, comparing rocket data in milliseconds to understand what was the cause of the accident and the final loss of telemetry in 0.893 seconds.
    The investigation is ongoing, SpaceX and the investigation team continue to analyze a significant amount of data, conduct additional tests in order to fully verify this version. However, with current data, we can claim to have identified the likely cause.

    Preliminary analysis showed that the increase in pressure in the oxygen tank of the upper stage was caused by the defective part of the structure (spacer) inside the second stage. The Falcon 9 booster has several hundred spacers, and several thousand were used during their operation. The spacer, which we consider to be defective, was certified for a load of 4,500 kilograms (10,000 pounds), but failed even with five times less load - 700 kilograms (2,000 pounds).

    In the case of the CRS-7 mission, presumably one of these parts inside the second stage collapsed at 138 seconds of flight. The pressurization system itself worked normally, but after the destruction of this spacer, the helium system was destroyed. This increase in pressure in the second stage led to the fact that the stage lost its structural integrity in a time less than a second.

    Despite the fact that these struts were used in all previous Falcon 9 flights and were certified for loads significantly exceeding flight, SpaceX will no longer use these struts in its products. In addition, SpaceX will conduct additional checks of all equipment used in the launch vehicle for compliance with certification documentation.

    As noted above, these are preliminary findings. Our investigation will continue until the reliability of all parts of the launch vehicle is checked, at the moment, we expect to return to flights in the fall and complete all flights planned for 2015.

    Despite the unfortunate loss of CRS-7, an analysis of this event will ultimately make our launch vehicle safer and more reliable for all customers, including NASA, the US Air Force and commercial customers. It is critical that our launch vehicle be even safer when we begin transporting U.S. astronauts to the ISS in 2017.

    Original text

    The same reason (the loss of the launch vehicle due to the destruction of the spacer holding the tank with liquid helium) Musk voiced at the ISSRDC 2015 conference . SpaceX currently has over 60 orders totaling over $ 7 billion .

    Joke of humor
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