A U.S. astronaut said on Thursday she had full confidence in the safety of the Russian-made Soyuz rocket that will blast a three-person crew into space next month in the first such launch since a rocket failure.
Russian cosmonaut Oleg Kononenko and U.S. and Canadian astronauts Anne McClain and David Saint-Jacques are due to embark for the International Space Station on Dec. 3 after a similar launch on Oct. 11 ended in an emergency landing.
Two minutes into that launch, a rocket failure forced Russian cosmonaut Alexei Ovchinin and U.S. astronaut Nick Hague to abort their mission and hurtle back to Earth in a capsule that landed in the Kazakh steppe. The two were unharmed.
Speaking at a news conference in Star City near Moscow, McClain said that occasional failures were inevitable, but that the mishap with the Soyuz-FG in October had demonstrated the reliability of its emergency safety mechanisms.
“We trust our rocket. We’re ready to fly,” she said at the conference also attended by her colleagues Kononenko and Saint-Jacques.
“A lot of people called it an accident, or an incident, or maybe want to use it as an example of it not being safe, but for us it’s exactly the opposite because our friends came home,” McClain told reporters.
Russian investigators said the rocket failure was caused by a sensor that was damaged during assembly at the Soviet era-cosmodrome at Baikonur from where McClain, Saint Jacques and Kononenko are due to launch.
Ahead of their mission, an unmanned rocket carrying cargo is due to launch on Nov 16. in what will be the first Soyuz-FG take-off from Baikonur since the mishap. (VOA)
Heart Rate gets altered in space but return to normal within 10 days on Earth, say researchers who examined cell-level cardiac function and gene expression in human heart cells cultured aboard the International Space Station (ISS) for 5.5 weeks.
Exposure to microgravity altered the expression of thousands of genes, but largely normal patterns of gene expression reappeared within 10 days after returning to Earth, according to the study published in the journal Stem Cell Reports.
“We’re surprised about how quickly human heart muscle cells are able to adapt to the environment in which they are placed, including microgravity,” said senior study author Joseph C. Wu from Stanford University.
These studies may provide insight into cellular mechanisms that could benefit astronaut health during long-duration spaceflight, or potentially lay the foundation for new insights into improving heart health on Earth.
Past studies have shown that spaceflight induces physiological changes in cardiac function, including reduced heart rate, lowered arterial pressure, and increased cardiac output.
But to date, most cardiovascular microgravity physiology studies have been conducted either in non-human models or at tissue, organ, or systemic levels.
Relatively little is known about the role of microgravity in influencing human cardiac function at the cellular level.
To address this question, the research team studied human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs). They generated hiPSC lines from three individuals by reprogramming blood cells, and then differentiated them into heart cells.
Beating heart cells were then sent to the ISS aboard a SpaceX spacecraft as part of a commercial resupply service mission.
Simultaneously, ground control heart cells were cultured on Earth for comparison purposes.
Upon return to Earth, space-flown heart cells showed normal structure and morphology. However, they did adapt by modifying their beating pattern and calcium recycling patterns.
In addition, the researchers performed RNA sequencing of heart cells harvested at 4.5 weeks aboard the ISS, and 10 days after returning to Earth.
These results showed that 2,635 genes were differentially expressed among flight, post-flight, and ground control samples.
Most notably, gene pathways related to mitochondrial function were expressed more in space-flown heart cells.
A comparison of the samples revealed that heart cells adopt a unique gene expression pattern during spaceflight, which reverts to one that is similar to groundside controls upon return to normal gravity, the study noted.
According to Wu, limitations of the study include its short duration and the use of 2D cell culture.
In future studies, the researchers plan to examine the effects of spaceflight and microgravity using more physiologically relevant hiPSC-derived 3D heart tissues with various cell types, including blood vessel cells.