1. Space Environment
Lecture 19 – Geospace Climate
Impact on space debris (part 2)
Professor Hugh Lewis
SESA3038 Space Environment
2. Overview of lectures 18 & 19
• In the next two lectures we will see the consequences of climate change in
the upper atmosphere on the space debris population in low Earth orbit
– These lectures bridge the topics we have covered this week and those
that are coming in future weeks
– There is *no* detailed introduction to the space debris problem or the
computational models used to investigate it. We will just look at the
results from the computational model DAMAGE applied to two basic
scenarios:
– The effects of a thermospheric density trend on LEO post-mission
disposal and active debris removal
– The effects of a prolonged solar minimum (like the Maunder
minimum from the 1600s) on LEO post-mission disposal and active
debris removal
Space Environment – Geospace Climate
3. Impact of prolonged minima on space
debris
Space Environment – Geospace Climate
Inter-Agency Space Debris
Coordination Committee (IADC)
definition:
“Space debris are all man made
objects including fragments and
elements thereof, in Earth orbit
or re-entering the atmosphere,
that are non functional.”
4. Cosmogenic isotope production Space Environment – Geospace Climate
Historical Carbon-14 measurements:
Changes in carbon-14 concentration in the Earth's atmosphere serve as a long
term proxy of solar activity
5. Solar activity assumptions Space Environment – Geospace Climate
We can use radio flux (specifically 10.7 cm wavelength) as a proxy of solar
extreme ultra-violet activity
Cycle 24
Cycle 25 Cycle 29
6. Solar activity assumptions Space Environment – Geospace Climate
Future F10.7 cm solar flux with Maunder-like minimum
Cycle 24 Cycle 29
7. Space Environment – Geospace Climate
Normal atmospheric
model, normal solar
activity
Modified atmospheric
model, with Maunder-
like minimum
90% compliance
90% compliance
Effects of prolonged solar minimum
90% compliance
8. Space Environment – Geospace Climate
Effects of prolonged solar minimum
Modified
atmospheric
model with
Maunder-like
minimum
1 2 3 4
9. Space Environment – Geospace Climate
Normal atmospheric
model, normal solar
activity
Modified atmospheric
model, with Maunder-
like minimum and
CO2 density tren (-2%
to -5% per decade)
90% compliance
Effects of prolonged solar minimum
and density trend
90% compliance
10. Space Environment – Geospace Climate
Modified atmospheric
model, with CO2
density trend (-2% to
-5% per decade)
Modified atmospheric
model, with Maunder-
like minimum and
CO2 density trend (-
2% to -5% per decade)
90% compliance
Effects of prolonged solar minimum
and density trend
90% compliance
11. Space Environment – Geospace Climate
Effects of prolonged solar minimum
and density trend
1 2 3 4
Modified
atmospheric
model with
Maunder-like
minimum and
CO2 density trend
12. Conclusions Space Environment – Geospace Climate
The effects of a prolonged minimum in solar activity
(e.g. Maunder-like):
• For the duration of the minimum:
• Population doubles by 2070
• Catastrophic collision risk doubles at 500-700 km altitude
• The population growth changes from quasi-stable to non-
linear increase
• Following the minimum:
• Population declines but does not return to the baseline level
• The population growth returns to quasi-stable
• Active debris removal can be used to complete
the recovery from the Maunder-like minimum
• The CO2 density trend prevents any recovery
13. Recap of lectures 18 & 19
• In the last two lectures we saw the consequences of climate change in the
upper atmosphere on the space debris population in low Earth orbit
– The effects of a thermospheric density trend on LEO post-mission
disposal and active debris removal
– The effects of a prolonged solar minimum (like the Maunder minimum
from the 1600s) on LEO post-mission disposal and active debris
removal
• In both scenarios, the long-term changes resulted in the loss of any
benefits from post-mission disposal and nominal active debris removal
– If solar activity returns to normal after a prolonged minimum, the
benefits return (and can be further improved by active debris removal)
but only in the absence of the density trend
Space Environment – Geospace Climate
14. Activities
• Reminder:
• You can find articles, book chapters,
and the Microsoft Excel orbital
lifetime calculator in the “Course
Contents” folder on the Blackboard
site
– The additional reading is not
compulsory but may help with a
deeper understanding of the topics
covered in this week’s lectures
Space Environment – Space Weather
