ESA UNCLASSIFIED - For Official Use

Active Debris Removal

Holger Krag, Klaus Merz, Tim Flohrer, Stijn Lemmens, Benjamin Bastida Virgili, Quirin Funke, Vitali Braun

ESA Space Debris OfficéOPS-GR, ESA/ESOC

23/05/2016

Holger Krag | 23//05/2016 | Slide 2ESA UNCLASSIFIED - For Official Use

Distribution of Catalogued Objects

Holger Krag | 23//05/2016 | Slide 3ESA UNCLASSIFIED - For Official Use

Environment Projections

• DELTA: Debris Environment Long-Term Analysis

• 3-D time dependent semi-deterministic model

• Simulation of environment response to mitigation actions

• Traffic Model derived from past 8 years

• Population 10 cm and above

• 40 Monte Carlo Runs

Holger Krag | 23//05/2016 | Slide 4ESA UNCLASSIFIED - For Official Use

Business As Usual

Holger Krag | 23//05/2016 | Slide 5ESA UNCLASSIFIED - For Official Use

Mitigation

Holger Krag | 23//05/2016 | Slide 6ESA UNCLASSIFIED - For Official Use

Instability of the Current Environment in LEO

[IADC-12-08, Rev. 1 January 2013]

Holger Krag | 23//05/2016 | Slide 7ESA UNCLASSIFIED - For Official Use

Analysis of Different Historical Populations

– Historic initial populations at different epochs from MASTER

Holger Krag | 23//05/2016 | Slide 8ESA UNCLASSIFIED - For Official Use

0.00%

10.00%

20.00%

30.00%

40.00%

50.00%

60.00%

70.00%

80.00%

90.00%

0 500 1000 1500 2000 2500 3000 3500Number of intact objects

% o

f run

s w

ith p

opul

atio

n in

crea

seStability of Historical Populations

2009

2005

1999

1989

1979

Threshold of stability

Holger Krag | 23//05/2016 | Slide 9ESA UNCLASSIFIED - For Official Use

Stability of Historical Populations

Holger Krag | 23//05/2016 | Slide 10ESA UNCLASSIFIED - For Official Use

The Role of Active Removal

Passivation

Post Mission Disposal

Active Removal

Holger Krag | 23//05/2016 | Slide 11ESA UNCLASSIFIED - For Official Use

Object Mass and Distribution in LEO

– Characteristics of the LEO environment

– Only 0.3% of the volume from 120km to super-GEO altitudes

– 77% of the catalogue population

– 40% of the on-orbit mass

Holger Krag | 23//05/2016 | Slide 12ESA UNCLASSIFIED - For Official Use

Orbital Regions of Interest (1/2)

Holger Krag | 23//05/2016 | Slide 13ESA UNCLASSIFIED - For Official Use

Orbital Regions of Interest (2/2)

Number of collisions after 200 years in no-further-release scenario

Orbital Lifetime

Holger Krag | 23//05/2016 | Slide 14ESA UNCLASSIFIED - For Official Use

Recent Changes to the Space Traffic

Holger Krag | 23//05/2016 | Slide 15ESA UNCLASSIFIED - For Official Use

Future Mega-Constellations

Announced LEO telecommunication constellations with > 100 satellites:

Constellation Name

Number of satellites

Orbital altitude [km]

Samsung 4600 1400

SpaceX 4000 1100

Oneweb 650 1200

Leosat LLC 140 1800

Yalini 135 600

Source: Various News Articles

Constellation 1080 satellites1100km altitude20 orbital planes85deg inclination

Mission Jan 2021 to Jan 2071

Satellite 200kg mass1m² effective cross-section5 years of mission lifetime

Constellation build-up

2018-201020 launches per year18 satellites per launch

Constellationmaintenance

2021-207118 objects per launch12 launches per year

Mitigation behaviour Launcher stages perform a direct re-entryNo mission-related objects are released

“Synthetic” Constellation Study Case

• Background: continuation of current traffic, excellent application of mitigation guidelines

Holger Krag | 23//05/2016 | Slide 16ESA UNCLASSIFIED - For Official Use

Mega Constellations and Post Mission Disposal Rates

Holger Krag | 23//05/2016 | Slide 17ESA UNCLASSIFIED - For Official Use

Current Disposal Efforts of LEO Constellations

[ESA DISCOS]

• State-of-the-art is at 20% (target is 90%)• Guidelines are sufficient – Adherence is insufficient

Holger Krag | 23//05/2016 | Slide 18ESA UNCLASSIFIED - For Official Use

ETS-VII

Past and current Experiments

ROKVISS

Cone Xpress

DEOS

Holger Krag | 23//05/2016 | Slide 19ESA UNCLASSIFIED - For Official Use

Determining the Attitude State1) Analysis of meter-scale range oscillation due to 2.5 m offset between retro and spin axis of body.

2) Analysis of the millimeter scale oscillations of the SLR range residuals; only for kHz SLR data …

retroreflector array of Envisat consists of 8+1 corner cube reflectors

Holger Krag | 23//05/2016 | Slide 20ESA UNCLASSIFIED - For Official Use

20x

ENVISAT: Inertial Spin, measured by SLR

[IWF Graz]

The spin period of Envisat:• increases by 72 ms/day• doubles every 4 years• will become equal to the orbital period (6000 s) in the year 2036

Holger Krag | 23//05/2016 | Slide 21ESA UNCLASSIFIED - For Official Use

Capture (uncontrolled re-entry): Ion Beam Shepherding

Holger Krag | 23//05/2016 | Slide 22ESA UNCLASSIFIED - For Official Use

Re-entry Risk

Ac

Ai

Ah

Ah= 0.36m2

0.36m²

50km

50km

• Ca. 10% increase in the number of uncontrolled re-entries per year• But targets are more heavy than average• However: Legal concerns!!

Holger Krag | 23//05/2016 | Slide 23ESA UNCLASSIFIED - For Official Use

Capture (controlled re-entry): Robotic Arm

Holger Krag | 23//05/2016 | Slide 24ESA UNCLASSIFIED - For Official Use

Capture (controlled re-entry): Net