Near Space
What is the altitude range considered near space?
20-100 km
What is D. radiodurans famous for?
Being the most radiation-resistant organism known
How many flights were conducted and in which years?
Three flights — 2019, 2020 and 2021
Which growth medium gave the highest survival rate overall?
TGY, the richest nutrient medium
What are the two main causes of death for microorganisms in near space?
UV radiation and extremely low temperature
At what growth phase were bacteria collected for the experiments and why?
Exponential phase, because it better reflects the characteristics of the growth environment
What was different about flight HH-21-5 compared to the previous ones? (The third)
Two devices were used in the same balloon to compare 2h and 4h exposure under the same atmospheric conditions
Why were survival rates similar in HH-19-9 and HH-20-7 despite the large difference in exposure time?
HH-19-9 flew at 32km with higher radiation but less time, HH-20-7 flew at 23km with less radiation but more time — the effects compensated each other
How do microorganisms reach near space?
Attached to dust particles carried by updrafts from Earth's surface
Why is D. radiodurans in stationary phase naturally more resistant to radiation?
Because it enters a dormant state, activating general stress resistance mechanisms
Why was the survival of the 4h group much lower than double that of the 2h group?
Because the 4h exposure included midday peak solar radiation, receiving far more than double the UV dose
By how much did survival increase in the glucose group when paraquat was added in HH-20-7?
267%