2. Overview of lecture 30
• In this lecture I use the results from a study of CubeSat collision risk
conducted in 2014 (and presented at the International Astronautical
Congress; the paper is available on the Blackboard site)
– The results are old but are still illustrative
– Conjunction data was sourced from SOCRATES
– The DAMAGE model was used to make future predictions of the number
of conjunctions and the resulting collision risk
• In the next lecture we will look at more recent data
Space Environment – Space Debris (Vol. 2)
3. CubeSats Space Environment – Space Debris (Vol. 2)
• Volume 10×10×10 cm
• Mass < 1.33 kg
• Applications include:
– Education
– Remote sensing
– Technology development
• “Most CubeSats fly at fairly low altitudes. They
will not stay in orbit for decades. Furthermore,
their trajectories can be controlled from launch,
and they can be tracked fairly easily with
radar. We know where they are, and where
they are going. Fragmentation due to impacts
with other objects is unlikely due to their small
size.”
8. Future CubeSat launches Space Environment – Space Debris (Vol. 2)
• Based on predictions by SpaceWorks Enterprises Inc.
9. DAMAGE simulations Space Environment – Space Debris (Vol. 2)
• Initial population of objects ≥ 10 cm residing in or crossing the LEO region
on 1 January 2013
• 30-year projection from 2013-2043
• Future launch traffic based on launches from 2005-2012
– Without new CubeSat launches, or
– With CubeSat launches corresponding to low, medium and high launch rates
• No explosions
• Spacecraft (except CubeSats) and rocket upper stages moved to decay orbits
with lifetimes < 25 years at end-of-life (90% compliance)
• 100 Monte Carlo runs for each scenario
13. DAMAGE results Space Environment – Space Debris (Vol. 2)
Impactor mass > 500 kg
Relative speed > 13.5 km/s
14. DAMAGE results/recap Space Environment – Space Debris (Vol. 2)
• More than 360,000 conjunctions < 5 km involving CubeSats since November
2005
• Millions of conjunctions predicted to occur in the next 30 years even for
relatively low CubeSat launch rates
– Many orbital regimes in LEO are affected
– Most likely collision scenario is CubeSat and large object in Sun-synchronous
orbit
– Relatively few collisions (< 2) predicted
• Forecasted CubeSat activity is not sustainable without engagement with &
leadership by “champions”, compliance with appropriate mitigation guidelines
& understanding the shared “duty of care” for the environment
15. Activity
• STRaND-1:
– As a precursor to the next lecture, you can
download the recent SOCRATES data from
the Blackboard site and attempt to count the
number of conjunctions < 5 km recorded.
– Compare to the worst-case values identified
in this lecture
• IAC 2014 paper
– The paper on which this lecture is based is
available on the Blackboard site for you to
read if you want to gain a deeper insight into
the work conducted
Space Environment – Space Debris (Vol. 2)
