SpaceX and NASA launch CRS-25 mission to the ISS

by Lee Kanayama

SpaceX launched its 25th commercial resupply services (CRS) mission for the International Space Station (ISS) on a flight-proven Falcon 9 while also utilizing a flight-proven Cargo Dragon 2 spacecraft. Falcon 9 B1067-5 lifted Dragon 2 Capsule 208-3 (C208-3) from Launch Complex 39A (LC-39A) on July 14 at 8:44 PM EDT (00:44 UTC on July 15).

CRS-25 was the third Dragon mission, SpaceX’s second CRS mission, and the overall 30th launch of the year.

With 29 flights under SpaceX’s belt, 2022 continues to set new milestones and records for the company. Using flight-proven rockets, SpaceX has kept an impressive cadence of one launch every ~6.7 days. CRS-25 used a flight-proven Falcon 9 and Dragon spacecraft.

SpaceX started using flight-proven Falcon 9 first stages in March 2017. The first mission to use a flight-proven booster was the SES-10 mission using B1021-2. A second booster, B1029-2, was reused during the BulgariaSat-1 mission in June 2017. By the end of 2017, five flight-proven Falcon 9 first stages were used.

As the years have gone by, SpaceX began using more flight-proven first stages to increase the speed of their launch cadence. In 2018, 13 flight-proven first stages were used, making up 61% of the launches that year. Over 75% of the first stages used in 2019 and 2020 were flight-proven. 2021 currently has the record of using the most flight-proven boosters at 93%.

Twenty-seven of the 29 launches in 2022 have been flight-proven, and SpaceX will continue to use multiple flight-proven first stages to test the limits of the boosters. On Starlink Group 4-16, B1062-6 completed a turnaround record of 21 days. Recently on Starlink Group 4-19, B1060-13 became the first booster to support 13 missions.

First stage B1067-5 was used on this mission. B1067 previously supported SpaceX CRS-22, Crew-3, Türksat 5B, and most recently the Crew-4 mission. Supporting the CRS-25 mission, B1067 will have supported four NASA and Dragon 2 missions. This will tie with B1061 as the booster to support most NASA missions.

This time around, B1067 had a turnaround time of 79 days.

B1067 launches the Crew-4 mission in April 2022. (Credit: Julia Bergeron for NSF)

In December 2020, the CRS-21 mission was launched beginning the CRS-2 contract. CRS-21 used Dragon C208-1. Now, CRS-25 is using Dragon C208-3.

C208 first supported the CRS-21 mission as the first CRS mission to use a Cargo Dragon 2. It later supported the CRS-23 mission as the first Cargo Dragon 2 to be reused. The CRS-25 mission will be the first time a Cargo Dragon 2 will support three missions.

A second Cargo Dragon 2 (C209) was introduced on the CRS-22 and was also used on CRS-24. Soon, a third Cargo Dragon 2 (C211) will be introduced to the Dragon 2 fleet. The CRS-2 contract now extends to CRS-35 after multiple contract extensions. With the three Cargo Dragon 2s, SpaceX will continue to support the ISS for multiple years to come.

CRS-25 is the latest mission for the CRS program. Preparations began for this mission following C208’s return on the CRS-23 mission. After a month at the orbiting lab, C208 successfully splashed down in the Atlantic Ocean. It was recovered by SpaceX’s recovery vessel Megan and taken to Port Canaveral. From there, C208 was taken to be refurbished for the CRS-25 mission.

During final spacecraft processing, the CRS-25 mission was delayed due to a mono-methyl hydrazine (MMH) leak. This leak was found after teams found elevated MMH vapor readings in the Dragon’s propulsion system. After multiple checkouts, the source of the leak was found at a Draco thrust valve inlet joint. This component — as well as any other components that were degraded from the vapors — were replaced.

SpaceX also replaced the main parachutes to allow a more detailed off-vehicle inspection. Once the issues were fixed, the spacecraft once again entered final processing for launch.

On the CRS-25 mission, it carries two external payloads in its trunk to the ISS. Both were loaded into the trunk in May 2022. Once the capsule was refurbished, the trunk was installed onto Dragon.

B1067-5 began its preparations after it supported the Crew-4 mission. After landing on SpaceX’s drone ship A Shortfall of Gravitas (ASOG), it was taken to Port Canaveral. From there, it was moved to SpaceX’s HangarX facility at Robert’s Road to be refurbished. It was spotted heading to LC-39A in late-May 2022.

ASOG departed Port Canaveral on July 12.

With about a week to go before launch, the completed Dragon was taken to the HIF at 39A. Then it was integrated with the second stage already attached to Falcon 9. With the Falcon 9 and Dragon integrated on the T/E, it was rolled out to the launch site on July 12.

Final launch day preparations began at T-38 minutes. During this time, the launch director (LD) conducted a Go/No-Go poll to begin propellant loading. The auto-launch sequence began propellant loading with RP-1 loading on the first and second stages and LOX (liquid oxygen) loading on the first stage.

Stage 2 RP-1 loading was complete at T-22 minutes. LOX loading on the second stage began six minutes later.

To ensure there are no thermal shocks with the engines at ignition, the first stage began to chill its engines with liquid oxygen at T-7 minutes. The T/E retracted to the launch position of 88.2 degrees at T-4 minutes and 30 seconds.

At T-1 minute before launch, two key events took place: nthe Falcon 9 entered “startup” when the flight computer took over the countdown. At the same time, the Falcon 9 tanks began to pressurize to flight pressure. At 45 seconds before launch, the LD give the final Go for launch.

At T-3 seconds, the nine first-stage engines were commanded to ignite. A second later, the engines ignited and then began a final health check. Once the engines were verified to be healthy and producing full thrust, the hydraulic hold-down clamps and the T/E retracted, allowing liftoff.

Falcon 9 (B1061-4) launches CRS-23. (Credit: SpaceX)

Shortly after liftoff, the Falcon 9 began a pitch maneuver to an azimuth to reach a 51.65-degree inclination. At one minute and 12-seconds into the flight, Falcon 9 reached Maximum Aerodynamic Pressure (Max-Q) where the aerodynamic forces were at their peak.

Stage 2’s Merlin Vacuum (MVac) engine began its engine chill at one minute and 40 seconds into flight.

After burning for two minutes and 31 seconds, the nine first-stage engines shut down. Three seconds later, both stages separated with the MVac engine igniting a few seconds after that.

Immediately after stage separation, the first stage began a flip maneuver. Three of the nine Merlin engines ignited for ~28 seconds for a partial boostback burn. The boostback burn slowed the first stage down to help reduce the stresses during atmosphere re-entry.

After coasting for three minutes, the first stage began a ~15-second, three-engine entry burn. This entry burn slowed the stage down to help protect it from the aerodynamic forces caused by entry. At T+7 minutes and 12 seconds, the first stage began a single-engine landing burn. This ~30-second burn slowed the stage to allow a gentle landing on ASOG.

Tbis was the 56th consecutive and the 130th overall landing of a Falcon 9 rocket and it continues SpaceX’s longest streak of consecutive landings since B1059’s failed landing during Starlink v1.0 L19 in February 2021. Now designated B1067-6, the first stage it will be taken back to Port Canaveral to be refurbished for a future mission.

Meanwhile, the second stage continued to orbit. Stage 2 burned for six minutes to reach an elliptical low-Earth parking orbit. Second engine cutoff (SECO)-1 occurred at T+8 minutes and 34 seconds. Just over three minutes later, Dragon separated from the second stage.

After separating from the second stage, Dragon began its on-orbit checks and systems activation. Its nosecone was open to reveal the forward-facing Drago thrusters and docking port. Once Dragon is confirmed healthy in orbit, it will begin a series of orbital phasing burns to reach the ISS.

Cargo Dragon 2 (C209-1) approaches the ISS before docking. (Credit: NASA)

Once at the ISS, Dragon will then maneuver to dock with the ISS. Dragon will dock with the IDA-3 on the forward-facing docking port on the Harmony module on July 16 at 11:20 AM EDT (15:20 UTC). It will remain at the ISS for roughly a month.

Now at the ISS, the crew will soon begin unloading the cargo from the Dragon. The cargo on Dragon includes science, supplies, and equipment for the ISS crews. The total mass of cargo on Dragon is ~2,630 kg of both pressurized and unpressurized cargo.

This mission will carry the Earth Surface Mineral Dust Source Investigation (EMIT) instrument developed by NASA’s Jet Propulsion Laboratory in Dragon’s trunk. EMIT will be used to measure the mineral composition of dust in Earth’s arid regions. This mineral dust can be blown into the air, and it can affect the climate, weather, vegetation, and more even at long distances.

EMIT will be placed on the exterior of the ISS. Over a year, EMIT will take photos to generate maps of mineral composition in the regions that produce dust.

A Battery Charge/Discharge Unit will also be carried in the trunk. This battery is a part of an investigation led by NASA’s Jet Propulsion Laboratory.

While not launched in the trunk, five CubeSats will be launched under the Educational Launch of Nanosatellites (ELaNa) 45 mission. The CubeSats were selected under NASA’s CubeSat Launch Initiative to provide low-cost access to space.

One CubeSat is the 3U BeaverCube developed by the Massachusetts Institute of Technology (MIT). BeaverCube will use multiple cameras to take images of the Earth’s oceans to detect the temperature of cloud tops and the ocean surface. This data will help understand the concentrations of phytoplankton.

The satellites will demonstrate the new Tiled Ionic Liquid Electrospray (TILE) 2 thruster. Learning how to use this new thruster will help future CubeSats maneuver while in space. TILE 2 will only weigh 0.5 kg with its delta-V at 10.1 m/s. BeaverCube will be deployed from a Poly-Picosatellite Orbital Deployer (P-POD) after arriving at the ISS.

Other CubeSats were developed by the Weiss School in Palm Beach Gardens, NASA’s Ames Research Center, Embry-Riddle Aeronautical University, and the University of South Alabama.

Multiple other educational institutes will have their scientific investigations on CRS-25. One study by the University of California at San Francisco is looking at the effects of aging while in microgravity. Aging is associated with changes in the immune response which is known as immunosenescence. The immunosenescence investigation will use tissue chips to study the effects of immune functions during flight and whether immune cells recover post-flight.

Flight hardware for the Biopolymer Research for In-Situ Capabilities. (Credit: James Wall/NASA)

The Biopolymer Research of In-Situ Capabilities is an experiment developed by Nanoracks and Stanford University. This research will be used to determine how microgravity affects the process of creating biopolymer soil composite (BSC). BSC, a concrete alternative made of organic compound and silica, will one day be used to create habitats on other planets. During the investigation in space, small bricks will be made using a Nanoracks platform and will be studied to determine their relative strength.

Developed by the Pacific Northwest National Laboratory and KSC, the Dynamics of the Microbiome in Space (DynaMoS) is a study on how microgravity affects the metabolic interactions in communities of soil microbes. On Earth, microorganisms conduct key functions in the soil. This research on the communities that decompose chitin will improve the understanding of microorganisms in space.

In partnership with Amplyus, Harvard Medical, and Boeing, the Genes in Space-9 is a platform for protein production that doesn’t include living cells. Cell-free protein production and biosensors will detect specific target molecules. This technology could provide portable, low-resource, and low-cost tools for potential medical applications.

The science on this mission will help our understanding of the effects in space/microgravity. However, the cargo on the CRS-25 is also not only science. It will also include fresh food, equipment for the ISS, and any clothing for the crew.

CRS-25 is the third of up to six missions planned for July. Just this week, SpaceX launched the Starlink Group 4-21 (B1058-13) and Starlink Group 3-1 (B1063-6) missions. After CRS-25, there will be at least three more Starlink missions planned for July: Group 4-22 (B1051-13) targeting July 17,  Group 3-2 (B1071-4) targeting July 21, and Group 4-25 (B1062-8).

August is another busy month with more Starlink and commercial missions. On August 2, 2022, a flight-proven Falcon 9 will launch the South Korean Danuri (KPLO) lunar orbiter on a trek to the Moon.

(Lead image: Falcon 9 (B1067-5) launches from LC-39A. Credit: Stephen Marr/NSF)

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