SpaceX-34 carries blood and bone research

NASA’s next cargo run to the International Space Station is not just a supply drop. It is also a flying lab for two stubborn human-spaceflight problems — blood changes and bone loss. The mission is SpaceX CRS-34, and as of Wednesday, May 13, NASA and SpaceX are targeting a 6:50 p.m. EDT launch after updating the schedule from the earlier May 12 plan. Dragon is carrying about 6,500 pounds of cargo, including experiments aimed squarely at what long stays in space do to the human body. ### What is actually flying? The headline human-health payloads are a blood study called SPARK and multiple bone-focused investigations, including Green Bone and the broader Microgravity Associated Bone Loss work NASA has been building out. SPARK will look at how red blood cells and the spleen change before, during, and after spaceflight. Green Bone will watch bone cells grow on a scaffold made from wood. The point is simple — figure out what microgravity breaks, then test ways to prevent it. (nasa.gov) ### Why are red blood cells a big deal? Because astronauts have been dealing with “space anemia” for decades. The weird part is that the problem is not just fluid shifting around the body in orbit. NASA-backed work has shown red blood cells are actually destroyed faster in space. That matters because red blood cells carry oxygen, and if your body has to keep rebuilding them under stress, long missions get harder fast. (nasa.gov) ### Why is the spleen in this story? The spleen is basically a quality-control organ for blood. It filters old or damaged red blood cells, stores some blood components, and plays a role in immune function. Researchers think the spleen may be one of the missing pieces in understanding how circulation, clotting risk, and red-cell turnover change in microgravity. That is why SPARK is not just “a blood study” — it is trying to connect the cells to the organ that manages them. (nasa.gov) ### Why is bone loss still unsolved? Because exercise helps, but it does not fully stop the damage. NASA says astronauts can still lose about 1% to 2% of bone mass per month in microgravity even with a rigorous exercise regimen. That is a huge problem for missions where people cannot just come home quickly. Bone is also not one thing — you have bone-forming cells, bone-degrading cells, signaling pathways, and stem cells all reacting to microgravity at once. (nasa.gov) ### What is Green Bone trying to do? Green Bone is a pretty clever test. Researchers are growing bone cells on a scaffold made from wood to see how those cells develop in space. The hope is that this kind of scaffold can teach scientists more about bone growth in microgravity and maybe point toward better treatments for brittle-bone conditions like osteoporosis back on Earth too. (science.nasa.gov) ### And what is MABL-B testing? MABL-B is more direct. It looks at how microgravity affects bone-forming and bone-degrading cells, and it tests whether blocking IL-6 signaling could work as a countermeasure. In plain English — researchers are not just watching bone loss happen. They are trying to interrupt the molecular pathway that may be helping cause it. (nasa.gov) ### Why does this cargo mission matter beyond the ISS? Because the ISS is still NASA’s best place to do controlled, repeatable human-biology work in real microgravity. Artemis and future Mars missions will expose crews to longer stretches away from Earth, with less room for medical improvisation and no quick return. Blood instability and bone loss are not side issues — they are mission constraints. (science.nasa.gov) ### Bottom line CRS-34 is a cargo mission, but the real story is that NASA is using it to chip away at two of the oldest biological problems in spaceflight. If SPARK and the bone studies produce useful answers, the payoff is bigger than this one launch — it could shape how astronauts stay healthy on the way to the Moon, Mars, and beyond. (nasa.gov) (science.nasa.gov)