A new record for cumulative time spent in space, SpaceX's ongoing regulatory challenges, heart diseases in space, and using X-rays against asteroids. This Week in Space.
Space Record Holder
Russian cosmonaut Oleg Kononenko returned last week from the International Space Station (ISS) with an impressive achievement – accumulating a total of 1,111 days in space. Kononenko, who celebrated his 60th birthday a few weeks ago while in orbit, is the first person to surpass the thousand-day mark in space. He reached this milestone over five missions to the ISS, with his latest mission setting a new record for the longest single stay on the station. Kononenko and fellow cosmonaut Nikolai Chub spent 374 days on the ISS, surpassing the previous record of 371 days set about a year ago. Along with them, American astronaut Tracey Dyson returned from space after spending "only" 184 days aboard the station.
The end of Kononenko and Chub's mission also marked the conclusion of the 71st crew's mission to the station, which has been continuously manned since late 2000, and the start of the 72nd crew's mission. She joined the crew unexpectedly, along with her colleague Barry Wilmore, after their planned eight-day stay on Boeing's "Starliner" test flight was extended due to spacecraft malfunctions. NASA decided to return the spacecraft empty and alter the crew's composition. Two additional crew members, American astronaut Nick Hague and Russian cosmonaut Alexander Gorbunov, were set to join the station last week, but their launch aboard SpaceX's Dragon spacecraft was postponed, due to a tropical storm in Florida.
"Oleg, we'll miss your hundreds of stories around the dinner table, but I guess that is what you get for having over a thousand days in space," Sunita Williams said, during the farewell ceremony for the astronauts returning to Earth and the station's command handover ceremony.
More than three years in space. Oleg Kononenko exits the Soyuz spacecraft after landing in Kazakhstan this week | Photo: NASA/GCTC/Pavel Shvets
Musk vs. the Rest of the World
SpaceX is currently awaiting approval for the fifth test of its Starship system – its massive spacecraft designed to land humans on the Moon and eventually on Mars. After the fourth test in June this year, the company announced it would be ready for a fifth launch as early as August. However, the U.S. Federal Aviation Administration (FAA) recently stated that approval for the next test is expected only by the end of November.
Meanwhile, the FAA decided a week ago to fine SpaceX over $600,000 for alleged regulatory violations related to its activities at the Cape Canaveral space base in Florida, unrelated to Starship launches, which take place in Texas. One fine, amounting to $350,000, was imposed following a launch in June this year, during which the company used an unauthorized communications room and skipped a required countdown step scheduled two hours before launch. Another fine of $283,000 was issued because, during a July launch, SpaceX used new refueling tanks without prior approval. In response, SpaceX sent a letter to Congress stating that these were minor issues that should not have been classified as violations or resulted in fines. SpaceX CEO and founder Elon Musk tweeted on X (the platform he owns) that the company intends to file a suit against the FAA for regulatory overreach.
The conflict escalated further last week when Musk called on FAA chief Michael Whitaker to resign. This was in response to Whitaker's remarks during a Congress hearing concerning SpaceX's safety requirements. The hearing, held by the United States House Committee on Transportation and Infrastructure Subcommittee on Aviation, primarily focused on safety issues with Boeing's aircraft manufacturing systems. Later, Republican Rep. Kevin Kiley mentioned the issues with the Starliner spacecraft and asked Whitaker if Boeing was not subject to looser oversight compared to what seems to be stricter scrutiny of SpaceX. Whitaker replied that the FAA acts based on safety considerations and that fines are the only tool they have to get compliance of safety matters. He further addressed Kiley’s question about the delays in FAA's licensing process for the fifth flight test of Starship, stating that it was also done for safety reasons and noted that Starshipn failed to provide an undated sonic boom analysis within the designated time frame. The company had already complained about three weeks ago that the report was delayed due to excessive demands from environmental regulators, including the Fish and Wildlife Service. Even before the hearing, Musk tweeted: "We need multiple Fish licenses to launch a rocket."
Adding to the heated debate, Republican presidential candidate Donald Trump entered the fray last week. While he did not directly address the issue of SpaceX's regulation, he promised at a campaign rally in North Carolina that, if elected, the United States would land on Mars by 2028. He even mentioned Musk, known as one of his supporters, as the one who would bring this vision to life, a goal Musk himself frequently discusses. In what may or may not be a related development, Musk presented another element of his updated Mars vision this week, stating that within the next two years, he intends to launch five uncrewed Starship missions to the neighboring planet in preparation for a manned launch. For now, realizing this vision depends not only on Musk's groundbreaking efforts but also on his ability to meet the safety and environmental requirements set by regulatory bodies.
When will it happen again? A previous launch of the Starship spacecraft from SpaceX's space base in Texas | Photo: Space
A Broken Heart in Space
Astronauts spending extended periods in microgravity face various medical challenges, including disturbances in heart rhythm and function. Studying the processes occurring in heart tissue is challenging without the possibility to take samples or analyze the biochemical processes involved. Since most astronauts understandably prefer to keep using their hearts rather than donate them to science while alive, this isn’t feasible. To address this challenge, researchers from the United States grew clusters of heart cells on a special chip and sent them to the International Space Station (ISS) for functional testing.
The heart cells were derived from induced pluripotent stem cells - adult body cells that researchers reprogrammed to a state where they could differentiate into various cell types, and then specifically induced them to become heart muscle cells. While growing, these cells formed clusters that contracted together, similar to a beating heart tissue. The clusters were grown on a platform resembling a suspended hammock between two tiny posts, one of which was flexible, allowing researchers to measure contractile cardiac function and strength in real time. A chip containing six such heart-on-a-chip devices, roughly half the size of a mobile phone, was launched for a one-month experiment on the ISS, while an identical chip remained on Earth as a control.
After 12 days aboard the space station, the researchers reported that the contraction strength of the heart-on-a-chip decreased by about half, while the hearts-on-a-chip that remained on Earth continued to beat with fairly constant strength. Additionally, the space hearts’ beats became increasingly irregular over time. Upon returning to Earth, the heartbeat rate quickly normalized, but the contraction strength remained weak even nine days post-landing.
Electron microscope examination of the cells brought back from space revealed that the protein fibers responsible for muscle contraction were shorter and less organized than those in the control cells that remained on Earth. Changes were also observed in the mitochondria – the energy-producing organelles of the cell – which appeared more swollen and, in some cases, torn. Analysis of the RNA composition in the cells showed that the cells exposed to space produced more proteins related to inflammatory processes and other stress conditions, while producing lesser amounts of the proteins necessary for normal heart function.
Measuring the activity of a few heart cells, especially those derived from stem cells, certainly does not reflect the complex array of processes occurring in the entire organ. The heart is also not an isolated system, and within the body, its activity is influenced by numerous factors, from the brain to blood pressure. However, the experiment is not designed to mimic this complex activity, but rather, "offers a useful means of identifying the molecular pathways behind the detrimental effects of space flight on the human heart," said cardiologist Joseph Wu from Stanford University. “The platform’s ability to function in a microgravity setting whilst maintaining tissue viability is a major advantage.” In the next stages, the researchers plan to conduct similar experiments for longer periods and include additional tissue types.
An automated heart-on-a-chip platform that maintains viability in space and monitors contractile cardiac function in real-time. The experimental setup sent to the space station | Photo: Deok-Ho Kim and Devin Mair / Johns Hopkins Medicine
X-ray Against Asteroids
One proposed strategy for dealing with an asteroid on a collision course with Earth is to divert it by detonating a nuclear bomb in space. The prevailing assumption is that the shock waves from the explosion would generate gases that push the asteroid off its trajectory. However, physicist Nathan W. Moore of the U.S. Sandia National Laboratories in Albuquerque, New Mexico suggests that the X-ray radiation emitted during the explosion could have an even greater impact on the asteroid. He demonstrated this in an intriguing experiment, albeit using "asteroids" the size of a grain of rice.
Moore and his colleagues used the lab’s powerful X-ray machine, which operates at approximately 80 trillion watts, to rapidly heat argon gas, transforming it into plasma that emits a strong X-ray beam. They directed this beam at two 12-millimeter blocks, one made of quartz and the other of silica, suspended inside a vacuum chamber to simulate the space environment.
In a paper published last week in Nature Physics, the researchers reported that the experiment lasted just 20 millionths of a second. The intense beam instantly melted the wire suspending the simulated asteroids, propelling them at a speed of about 70 meters per second (approximately 250 km/h) before they completely evaporated. The acceleration was caused by the vaporization of the asteroid's surface, with the pressure of the released gas pushing them away rapidly.
According to Moore, this method could be applied to much larger asteroids, up to four kilometers in diameter, to divert them from a collision course with Earth. “In particular, we’re interested in the largest asteroids with a short warning time,” he explained, as alternative approaches, such as a mechanical collision of a spacecraft with an asteroid, like NASA's DART mission, "might not have enough energy to knock it off course”.
Naturally, this method presents challenges, including the risks associated with launching a nuclear bomb into space. However, the experiment provides hope that, in the event of a large asteroid being identified on a collision course with Earth, we will have a range of tools at our disposal to protect the planet and its inhabitants.
It's not the nuclear explosion itself, but the X-ray radiation that could deflect the asteroid. Illustration of an explosion near an asteroid on a collision course with Earth | Detlev Van Ravenswaay/Science Photo Library