A SpaceX cargo Dragon spacecraft docked to the ISS after a July 14 launch, delayed more than a month by a hydrazine leak on the spacecraft.
July 16, 2022 The SpaceX Dragon cargo spacecraft (C208.3) autonomously docked to the forward-facing port of the station’s Harmony module at 11:21 a.m. EDT (16:21 UTC) today, The Dragon launched on SpaceX’s 25th contracted commercial resupply mission for NASA at 8:44 p.m., Thursday, July 14, from Launch Complex 39A at the agency’s Kennedy Space Center in Florida. After Dragon spends about one month attached to the space station, the spacecraft will return to Earth with cargo and research.
The Dragon spacecraft, flying a mission designated CRS-25, is carrying 2,668 kilograms of cargo, including science investigations as well as crew supplies, spacewalk equipment, and hardware. That total includes 544 kilograms of equipment located in the unpressurized trunk section of the spacecraft.
Among the science experiments Dragon is delivering to the space station are:
Mapping Earth’s Dust The Earth Surface Mineral Dust Source Investigation (EMIT), developed by NASA’s Jet Propulsion Laboratory in Southern California, employs NASA imaging spectroscopy technology to measure the mineral composition of dust in Earth’s arid regions. Mineral dust blown into the air can travel significant distances and affect Earth’s climate, weather, vegetation, and more. For example, dust containing dark minerals that absorb sunlight can warm an area, while light-colored mineral dust can cool it. Blowing dust also affects air quality, surface conditions such as the rate of snow melt, and phytoplankton health in the ocean. The investigation collects images for one year to generate maps of the mineral composition in the regions on Earth that produce dust. Such mapping could advance our understanding of the effects of mineral dust on human populations now and in the future.
Speedier Immune System Aging Aging is associated with changes in the immune response known as immunosenescence. Microgravity causes changes in human immune cells that resemble this condition, but happen faster than the actual process of aging on Earth. The Immunosenescence investigation, sponsored by International Space Station U.S. National Laboratory, uses tissue chips to study how microgravity affects immune function during flight and whether immune cells recover post-flight. Tissue chips are small devices that contain human cells in a 3D structure, allowing scientists to test how those cells respond to stresses, drugs, and genetic changes.
Soil in Space On Earth, complex communities of microorganisms carry out key functions in soil, including cycling of carbon and other nutrients and supporting plant growth. Dynamics of Microbiomes in Space sponsored by NASA’s Division of Biological and Physical Sciences examines how microgravity affects metabolic interactions in communities of soil microbes. This research focuses on microbe communities that decompose chitin, a natural carbon polymer on Earth.
High School Student Weather Study
BeaverCube is an educational mission that will teach high school students aerospace science by having them design a CubeSat. BeaverCube will host one visible and two infrared imagers to measure cloud properties, ocean surface temperatures, and ocean color to study Earth’s climate and weather systems. It also will demonstrate an application for the use of shape memory alloy technology via an in-orbit calibration technique.
Genes, No Cells Cell-free technology is a platform for producing protein without specialized equipment of living cells that need to be cultured. Genes in Space-9, sponsored by the National Lab, demonstrates cell-free production of protein in microgravity and evaluates two cell-free biosensors that can detect specific target molecules. This technology could provide a simple, portable, and low-cost tool for medical diagnostics, on-demand production of medicine and vaccines, and environmental monitoring on future space missions.
Better Concrete Biopolymer Research for In-Situ Capabilities looks at how microgravity affects the process of creating a concrete alternative made with organic material and on-site materials, such as lunar or Martian dust, known as biopolymer soil composite. Using resources available where construction takes place makes it possible to increase the amount of shielding.
These are just a few of the hundreds of investigations currently being conducted aboard the orbiting laboratory in the areas of biology and biotechnology, physical sciences, and Earth and space science. Advances in these areas will help 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 through NASA’s Artemis program
“We really need to be able to model how dust interacts with the full Earth system,” said Robert Green, principal investigator for EMIT at the Jet Propulsion Laboratory, during a NASA briefing in June. EMIT will provide far more data on mineral dust than other sensors. “We will use these new measurements to update those Earth system models and bring better fidelity to the Earth system models.” The instrument will also support planning for the Earth System Observatory line of future missions.
Launch Delay of CRS-25 mission
The CRS-25 mission had been scheduled to launch in early June. However, NASA and SpaceX postponed the launch after detecting what NASA called “elevated vapor readings” of hydrazine in the spacecraft’s propulsion system. Dragon uses monomethyl hydrazine and nitrogen tetroxide as propellants for its Draco thrusters that handle its approach to and departure from the ISS, and deorbiting at the end of the mission.
At a prelaunch briefing July 13, Benji Reed, senior director of human spaceflight programs at SpaceX, said the company traced the leak to imperfections in a “sealing surface” where a valve connects into the propulsion system. “We replaced that valve and then we thoroughly tested the system to confirm that there is no further leakage,” he said.
He added the problem was not with the valve itself but with the sealing of joints and unions in the plumbing. The sealing surface around the valve had been “reworked” but appeared fine, he said. Initial tests of the propulsion system during assembly did not detect a leak but may not have been sufficient to detect that leak if it existed at that time. SpaceX found the leak only in “full up” system testing ahead of launch.
“Since then we have made updates to our processes,” Reed said. One involves how to do rework on sealing surfaces for “stricter acceptability.” The company is also incorporating more rigorous testing processes.
The issue is isolated to the Dragon spacecraft flying this mission. “We did look very closely at that,” he said but didn’t find similar problems on other Dragon spacecraft in the fleet. There’s also no sign of any leak on the Crew Dragon spacecraft currently docked to the station on the Crew-4 mission.
During the investigation of this leak, SpaceX decided to replace the parachutes on the spacecraft. Reed said that was done as a precaution because hydrazine vapors could have degraded the parachutes. “The initial results from those inspections are coming in and those original parachutes look great,” he said. “We’ll likely use those on a future mission if the teams determine they’re safe to use for flight.”
Dana Weigel, NASA ISS deputy program manager, said at the prelaunch briefing that NASA plans to keep Dragon at the station for 33 days before undocking and splashing down off the Florida coast. The spacecraft will bring back about 50 science investigations as well as space station hardware that is being repaired or replaced.
That includes a spacesuit that suffered a small water leak during a March spacewalk, or EVA, by European Space Agency astronaut Matthias Maurer, causing water to pool on his helmet visor. NASA has since suspended spacewalks at the station except for contingencies.
Weigel said NASA is eager to get the suit back so engineers can determine the cause of the leak. “That’s really key for us,” she said. “That will be part of what we need for our assessment” to allow spacewalks to resume.