ISS Utilization: SpaceX CRS-18 Flight
Launch: NASA commercial cargo provider SpaceX launched the CRS-18 (Commercial Resupply-18) Dragon mission to the ISS on 25 July 2019 (22:01 UTC). SpaceX launched its CRS-18 mission from Space Launch Complex 40 (SLC-40) at Cape Canaveral Air Force Station, Florida. Dragon separated from Falcon 9's second stage about nine minutes after liftoff and will attach to the space station on Saturday, July 27. 1)
Orbit: Near circular orbit, altitude of ~400 km, inclination = 51.6º.
Figure 1: A SpaceX Dragon cargo spacecraft launches to the ISS on a Falcon 9 rocket at 6:01 p.m. EDT (220.1 UTC) July 25, 2019 (image credit: NASA)
Originally scheduled to launch July 24, unfavorable weather conditions caused a last-minute scrub. The morning of July 25, the weather looked much the same but cleared up just in time.
After a picture-perfect launch and spacecraft separation, Dragon is now drawing power from its solar arrays as it begins its solo, two-day trip to the orbiting laboratory. This is the first time a Dragon spacecraft will journey to the space station for a third time. To mark this accomplishment, it is outfitted with three noteworthy stickers: two station badges representing the previous resupply missions it has flown (CRS-6 and CRS-13) and the Apollo 50th anniversary logo.
Dragon will join three other spacecraft currently at the space station. Expedition 60 Flight Engineers Nick Hague and Christina Koch of NASA will use the station's robotic arm, Canadarm2, to grab, or grapple, Dragon around 10 a.m. Coverage of robotic installation to the Earth-facing port of the Harmony module will begin at 12 p.m. 2) 3)
A key item in Dragon's unpressurized cargo section is International Docking Adapter-3 (IDA-3). Flight controllers at mission control in Houston will use the robotic arm to extract IDA-3 from Dragon and position it over Pressurized Mating Adapter-3, on the space-facing side of the Harmony module. Hague and NASA astronaut Drew Morgan, who arrived at the station Saturday, July 20, will conduct a spacewalk in mid-August to install the docking port, connect power and data cables, and set up a high-definition camera on a boom arm.
Robotics flight control teams from NASA and the Canadian Space Agency will move the docking port into position remotely before the astronauts perform the final installation steps. IDA-3 and IDA-2, which was installed in the summer of 2016, provide a new standardized and automated docking system for future spacecraft, including upcoming commercial spacecraft that will transport astronauts through contracts with NASA.
This delivery, SpaceX's 18th cargo flight to the space station under a Commercial Resupply Services contract with NASA, will support dozens of new and existing investigations. The space station continues to be a one-of-a-kind laboratory where NASA is conducting world-class research in fields, such as biology, physics, and materials science. NASA's research and development work aboard the space station contributes to the agency's deep space exploration plans, including returning astronauts to the Moon's surface in five years and preparing to send humans to Mars.
Dragon is loaded with about 5000 pounds (~2260 kg) of supplies and payloads, including critical materials to directly support more than 250 science and research investigations that will occur onboard the orbiting laboratory.
• Payload launch mass: 4200 kg (Dragon) + 1290 kg (fuel) + 2221 kg payload mass = 7700 kg launch mass
• ISS payload mass: 529.9 kg (IDA-3) + 1691.3 kg (Internal Cargo) = 2221.2 kg total.
The CRS-18 launch included also a recovery attempt for the Falcon 9 . It returned and landed as planned at the company's LZ-1 landing zone at Cape Canaveral Air Force base. The first-stage booster separated from the second-stage and the Dragon craft as planned, and then returned to Earth, landing successfully after a controlled descent. This was SpaceX's 44th successful recovery of a Falcon 9 first-stage after launch. 4)
Here are details about some of the scientific investigations Dragon is delivering to the space station:
Bio-Mining in Microgravity: The Biorock investigation will provide insight into the physical interactions of liquid, rocks and microorganisms under microgravity conditions and improve the efficiency and understanding of mining materials in space. Bio-mining eventually could help explorers on the Moon or Mars acquire needed materials, lessening the need to use precious resources from Earth and reducing the amount of supplies that explorers must take with them.
Printing Biological Tissues in Space: Using 3D biological printers to produce usable human organs has long been a dream of scientists and doctors around the globe. However, printing the tiny, complex structures found inside human organs, such as capillary structures, has proven difficult to accomplish in Earth's gravity. To overcome this challenge, Techshot designed their BioFabrication Facility to print organ-like tissues in microgravity – a stepping stone in a long-term plan to manufacture whole human organs in space using refined biological 3D printing techniques.
Improving Tire Manufacturing from Orbit: The Goodyear Tire investigation will use microgravity to push the limits of silica fillers for tire applications. A better understanding of silica morphology and the relationship between silica structure and its properties could improve the silica design process, silica rubber formulation and tire manufacturing and performance. Such improvements could include increased fuel efficiency, which would reduce transportation costs and help to protect Earth's environment.
Effects of Microgravity on Microglia 3D Models: Induced pluripotent stem cells (iPSC) – adult cells genetically programmed to return to an embryonic stem cell-like state – have the ability to develop into any cell type in the human body, potentially providing an unlimited source of human cells for therapeutic purposes. Space Tango-Induced Pluripotent Stem Cells examines how specialized white blood cells derived from iPSCs of patients with Parkinson's disease and multiple sclerosis grow and move in 3D cultures, and any changes in gene expression that occur as a result of exposure to a microgravity environment. Results could lead to the development of potential therapies.
Mechanisms of Moss in Microgravity: Space Moss compares mosses grown aboard the space station with those grown on Earth to determine how microgravity affects its growth, development, and other characteristics. Tiny plants without roots, mosses need only a small area for growth, an advantage for their potential use in space and future bases on the Moon or Mars. This investigation also could yield information that aids in engineering other plants to grow better on the Moon and Mars, as well as on Earth.
These are just a few of the hundreds of investigations providing opportunities for U.S. government agencies, private industry, and academic and research institutions to conduct microgravity research that leads to new technologies, medical treatments, and products that improve life on Earth. Conducting science aboard the orbiting laboratory will help us learn how to keep astronauts healthy during long-duration space travel and demonstrate technologies for future human and robotic exploration beyond low-Earth orbit to the Moon and Mars.
For more than 18 years, humans have lived and worked continuously aboard the International Space Station, advancing scientific knowledge and demonstrating new technologies, making research breakthroughs not possible on Earth that will enable long-duration human and robotic exploration into deep space. A global endeavor, more than 230 people from 18 countries have visited the unique microgravity laboratory that has hosted more than 2,500 research investigations from researchers in 106 countries.
RUBI (Reference mUltiscale Boiling Investigation) of ESA. RUBI is among the upcoming investigations to be operated in ESA's FSL (Fluid Science Laboratory), addressing the fundamentals of single bubble pool boiling and the bubble interaction with an electrostatic field and shear flow. The Soft Matter Dynamic instrument has multiple objectives covering the studies of foam coarsening, emulsions stabilization and dynamics in agitated granular matter and has been designed in such a way to be able to detect and analyze multiple scattering light in order to monitor the dynamics and the temporal evolution of these systems. The RUBI payload has a mass of 34 kg.
FSL is a multi-user facility for conducting fluid physics research in microgravity conditions providing a central location to perform fluid physics experiments onboard the ISS that gives insight into the physics of fluids covering areas such as foam and emulsion stability, geophysical fluid flow and thermodiffusion. An enhanced understanding of how fluids behave in space and on Earth will help researchers improve mathematical models of fluids and geophysical processes and may lead to improvements in many industrial processes involving fluid system.
Figure 2: SpaceX CRS-18 Research Overview, International Space Station U.S. National Laboratory. The International Space Station U.S. National Laboratory is sponsoring more than 50 experiments that are launching onboard SpaceX's 18th commercial resupply services mission to the orbiting laboratory. This launch represents more payloads that the ISS National Lab has ever supported on a single launch. From life and physical sciences, education demonstrations, new facilities to support future biomedical payloads, and more, are all on this mission! This overview video provides a snapshot of the research flying on this mission (ISS National Lab, Published on 18 July 2019)
• August 27, 2019: SpaceX's CRS-18 Dragon spacecraft has concluded her EOM (End Of Mission) milestones, following unberthing from the International Space Station (ISS) on Tuesday. Dragon's release from the Space Station Remote Manipulator System (SSRMS) occurred at 14:59 UTC, with splashdown in the Pacific Ocean around 20:20 UTC. 5)
- The CRS-18 Dragon was launched on Falcon 9 B1056.2 on 25 July 2019. This was the same booster that had also launched the CRS-17 Dragon.
- Dragon delivered over 2,500 kg of cargo in her pressurized, including food and consumables for the ISS crew and several major scientific investigations set to be carried out in the space station's microgravity environment.
- One of the largest pieces of equipment is the third International Docking Adapter (IDA-3), which was lofted in the Dragon's unpressurized "trunk" and removed during docked operations.
- This was recently installed to Pressurized Mating Adapter-3 on the space-facing side of the station's Harmony module during EVA-55.
- Ahead of the return trip, Dragon was packed with downmass and the hatch closed. Dragon will be returning almost 2,700 pounds of scientific experiments and other cargo as downmass, including some numerous samples.
- Robotic ground controllers then used the robotic arm to detach Dragon from the Earth-facing port of the Harmony module to maneuver Dragon into the release position.
- Dragon was unberthed by the Space Station Remote Manipulator System (SSRMS) before being released from the robotic arm at 14:59 UTC. This was slightly later than planned due to the requirement to gain better lighting conditions.
- Once the LEE snares were released, the SSRMS was backed away from Dragon as the craft held its position at the 10-meter mark.
- Once the Station's arm was cleared to a safe distance, Dragon conducted a series of three small thruster firing departure burns that moves the capsule down the R-Bar (Radial Vector) and away from the International Space Station toward Earth (when viewed in relation to ISS orientation and Dragon movements with respect to Earth).
- During the initial stage of departure, Dragon was under the control of its own computer programming, with the Station crew and controllers at Mission Control Houston in Texas for NASA having primary control over the spacecraft.
- As Dragon pushed down the R-Bar, the largest of the three thruster departure burns imparted enough Delta Velocity (Delta-V) change to Dragon to push it outside of the approach ellipsoid.
Figure 3: ISS departure zone (image credit: NASA)
- The approach ellipsoid is a 4 km by 2 km oval-shaped region around the International Space Station that extends 2 km in front of and 2 km behind the ISS along the velocity vector (V-Bar) and 1 km above and 1 km below the Station along the R-Bar.
- Once Dragon cleared the approach ellipsoid 1 km below the ISS, primary control of the vehicle shifted from NASA to SpaceX controllers in Hawthorne, California.
- Dragon conducted several hours of free flight activities as controllers at Mission Control SpaceX prepared the vehicle for the end of its mission.
- This included the closure of the Guidance Navigation and Control (GNC) bay door on Dragon, creating a perfect thermal protection seal around the entirety of Dragon for entry.
- SpaceX flight controllers at Hawthorne, California commanded Dragon's Draco thrusters to fire for 12 minutes and 53 seconds – retrograde – in the deorbit burn. This enabled Dragon to slip out of orbit for its descent back to Earth.
- Following the deorbit burn, the umbilicals between Dragon and her external payload trunk were severed ahead of the trunk's separation from Dragon itself.
- Dragon then placed its heat shield out in front in preparation for Entry Interface (EI) – the moment Dragon reached the first traces of Earth's upper atmosphere.
- Once EI occurred, Dragon's Thermal Protection System (TPS) protected it from the searing hot temperatures of reentry formed as the air molecules around Dragon are instantly heated and turned to plasma under the friction created by Dragon's high velocity.
- Dragon's primary heat shield, called PICA-X, is based on a proprietary variant of NASA's Phenolic Impregnated Carbon Ablator (PICA) material and is designed to protect Dragon during atmospheric re-entry.
- PICA-X is robust enough to protect Dragon not only during ISS return missions but also during high-velocity returns from Lunar and Martian destinations. There were also signs of some experimental tiles on the Dragon that are understood to be related to SpaceX's Starship test program.
- Unlike the Dragon capsule, the Dragon trunk destructively burns up in Earth's atmosphere.
- Once safely through the plasma stage of reentry, Dragon's drogue parachutes deployed, followed by the main chutes designed to ease the vehicle to a splashdown in the Pacific Ocean for recovery.
Figure 4: Dragon splashdown (image credit: NASA)
- Recovery is attained by three main recovery vessels which were positioned near Dragon's return location. The main recovery vehicle had already set sail earlier in the last few days.
- Fast recovery vessels deploy, collecting Dragon's parachutes as the recovery of the capsule itself is conducted by the primary recovery assets.
- Dragon will eventually take a road trip to SpaceX's test center at McGregor in Texas for the complete cargo removal.
• On 27 July 2019, two days after its launch from Florida, the SpaceX Dragon cargo spacecraft was installed on the Earth-facing side of the International Space Station's Harmony module at 12:01 p.m. EDT. 6)
Figure 5: July 27, 2019: International Space Station Configuration. Five spaceships are parked at the space station including the SpaceX Dragon cargo craft, Northrop Grumman's Cygnus space freighter, the Progress 72 resupply ship and the Soyuz MS-12 and MS-13 crew ships (image credit: NASA)
- The 18th contracted commercial resupply mission from SpaceX (CRS-18) delivers more than 5,000 pounds of research, crew supplies and hardware to the orbiting laboratory.
- A key item in Dragon's unpressurized cargo section is International Docking Adapter-3 (IDA-3). Flight controllers at mission control in Houston will use the robotic arm to extract IDA-3 from Dragon and position it over Pressurized Mating Adapter-3, on the space-facing side of the Harmony module. NASA astronauts Nick Hague and Andrew Morgan, who arrived at the station Saturday, July 20, will conduct a spacewalk in mid-August to install the docking port, connect power and data cables, and set up a high-definition camera on a boom arm.
- Robotics flight control teams from NASA and the Canadian Space Agency will move the docking port into position remotely before the astronauts perform the final installation steps. IDA-3 and IDA-2, which was installed in the summer of 2016, provide a new standardized and automated docking system for future spacecraft, including upcoming commercial spacecraft that will transport astronauts through contracts with NASA.
- After Dragon spends approximately one month attached to the space station, the spacecraft will return to Earth with cargo and research.
• On July 27 2019, Dragon was captured at the ISS. While the ISS was traveling over southern Chile, astronauts Nick Hague and Christina Koch of NASA grappled Dragon at 9:11 a.m. EDT using the space station's robotic arm Canadarm2. 7)
Figure 6: The SpaceX Dragon is in the grips of the Canadarm2 robotic arm shortly after it was captured over southern Chile (image credit: NASA)
- Ground controllers will now send commands to begin the robotic installation of the spacecraft on bottom of the station's Harmony module.
2) "SpaceX Dragon on Route to Space Station with NASA Science, Cargo," NASA Release 19-058, 26 July 2019, URL: https://www.nasa.gov/press-release
3) "CRS-18 Mission," SpaceX Press Kit, 25 July 2019, URL: https://www.spacex.com
5) Chris Bergin, "CRS-18 Dragon completes mission with Pacific Ocean Splashdown," NASA Spaceflight.com, 27 August 2019, URL: https://www.nasaspaceflight.com
The information compiled and edited in this article was provided by Herbert J. Kramer from his documentation of: "Observation of the Earth and Its Environment: Survey of Missions and Sensors" (Springer Verlag) as well as many other sources after the publication of the 4th edition in 2002. - Comments and corrections to this article are always welcome for further updates (firstname.lastname@example.org).