SpaceX Falcon 9 Block 5 - CRS-16 - Launching December 5, 2018
Screenshot of CRS-16 from SpaceX with Tim Dodd as host
Mission Rundown: SpaceX Falcon 9 Block 5 - CRS-16
Written: January 10, 2021
Mission view of CRS-16 by Geoff Barrett
The taller they are, the harder they fall
NASA is paying SpaceX to launch a Dragon on a resupply mission to the International Space Station. The Falcon 9 booster B1050 is on its first launch into orbit. The Dragon will additionally deliver the new External High Definition Camera Assembly and two NORS O2 Recharge Tanks to support future spacewalks.
SpaceX is targeting Saturday, December 5 for an instantaneous launch of its sixteenth Commercial Resupply Services mission - CRS-16 at 02:48 a.m. EDT, or 06:48 UTC, from Space Launch Complex 40 - SLC-40 at Cape Canaveral Air Force Station, Florida. Dragon will separate from Falcon 9’s second stage about 9 minutes after liftoff and attach to the space station on Monday, May 6. That didn't happen before 15:36 UTC Dec. 8, 2018.
The Dragon I spacecraft that will support the CRS-16 mission previously supported the CRS-10 mission in february 2017. Following stage separation, SpaceX will attempt to recover Falcon 9’s first stage on the Of Course I Still Love You drone ship, stationed in the Atlantic Ocean.
CRS-16 is the 16th commercial resupply mission, which was awarded to SpaceX in February of 2016. In February of 2016, NASA extended the CRS-1 contract with SpaceX to include 5 additional resupply missions. CRS 16 is the first of those five.
The Cargo Dragon is expected to arrive at the ISS after three days. Once it navigates into position, it will be captured by the Canadarm, and then berthed to the station a few hours later. NASA TV will provide coverage of the arrival, capture and berthing. After about 30 days Dragon will depart ISS, ditch its trunk, reenter the atmosphere and splash down in the Pacific Ocean.
The Reentry Burn timeline
A rare opportunity presented itself when watching the reentry burn at T+00:06:39, where the center Merlin 1D# ignited four seconds ahead of the other two, which ignited at T+00:06:43. They all burn together until T+00:06:57, where the center engine again burns alone until shutdown at T+00:06:59 giving a total burntime of 20 seconds.
After the reentry burn at T+00:07:15 the camera is hit by fluids, which make me think the hydraulics to one grid fin punctured, thus disabling it and causing the landing failure. The hydraulic fluid is for all practical purposes RP-1 rocket fuel, there is no need to have a special separate hydraulic reservoir oil tank, when RP-1 works just the same.
This could explain some rocket engine fires after hard or hot landings on the barges, simply that the hydraulic fluid is a highly flammable liquid and if a hydraulic line burst, then the superheated rocket engines would catch fire. Alternatively an electric arc from a plasma charged rocket engine could do the deed. Some Block 4 boosters did catch fire right after landings on the barges.
The first stage booster B1050 experienced a grid fin hydraulic pump stall on re-entry. This caused the first stage to go into a roll after the re-entry burn. It failed to reach Landing Zone 1, but recovered enough to achieve a soft water landing off Cape Canaveral.
That grid fin hydraulic pump stall mentioned here could be a ruptured hydraulic fluid line, and a check valve blocked for further inflow of hydraulic fluid in the hydraulic pump, that without a work pressure couldn't keep the hydraulic check valve open. No back pressure in a hydraulic actuator means a leak and it isn't working, so there's no need to keep pumping hydraulic fluid into a broken pump.
Shortly after the landing, Elon Musk, CEO of SpaceX, stated the booster appeared to be undamaged and was being recovered. After recovering the booster, it was found to be too damaged to fly again and was later scrapped for parts.
The Dragon Payload
SpaceX CRS-16, also known as SpX-16, was a Commercial Resupply Service mission to the International Space Station launched on 5 December 2018 aboard a Falcon 9 launch vehicle. The mission was contracted by NASA and is flown by SpaceX.
This CRS mission is the first with the Falcon 9 Block 5. It carried the Global Ecosystem Dynamics Investigation (GEDI) lidar and the Robotic Refueling Mission 3 (RRM3) experiment as external payloads.
CRS-16 carried a total of 2 573 kg (5 672 lb) of material into orbit. This included 1 598 kg (3 523 lb) of pressurized cargo with packaging to the International Space Station, and 975 kg (2 150 lb) of unpressurized cargo composed of two external ISS experiments: the Global Ecosystem Dynamics Investigation (GEDI) lidar - the Robotic Refueling Mission 3. Forty mice also flew with the payload in an experiment called Rodent Research-8 (RR-8).
The CRS-16 mission also carried a pair of CubeSats originally planned to launch aboard the Cygnus NG-10 International Space Station (ISS) cargo resupply mission, but which were deferred. These included the UNITE CubeSat from the University of Southern Indiana and the TechEdSat-8 CubeSat from NASA's Ames Research Center.
On 13 January 2019, Dragon was released from ISS at 23:33 UTC and deorbited, splashing down in the Pacific Ocean approximately 5 hours later on 14 January 2019 at 05:12 UTC, returning more than 2 500 kg (5 500 lb) of cargo to Earth.
SpaceX technicians will after splashdown open the side hatch of the Dragon vehicle and retrieve the time-critical refrigerated items. The critical cargo items were placed on a fast-boat for the 450 kilometers (280 mi) trip back to California for eventual return to NASA that then took care of the precious science cargo and handled the post-flight analysis of the samples.
The rest of the cargo was unloaded once the Dragon capsule reached SpaceX's test facility in McGregor, Texas.
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