The document discusses a proposed system to remove space debris using a small microsatellite. It would use an electrodynamic tether (EDT) technology, which allows orbital transfers without propellant. The microsatellite would have a compact design, thrusters for maneuvering, sensors for navigation, and an extensible robotic arm to capture debris. It describes the key components like the EDT, release mechanism, reel mechanism, navigation sensors, and robotic arm. The system aims to provide an affordable way to actively remove large debris from useful orbits and address the growing issue of space debris.

1. WELCOME

2. SPACE DEBRIS REMOVAL USING A SMALL SATELLITE
Guided by
Mr Jobin,
Assistant professor,
Mechanical department

3.  Introduction
 Overview on space debris
 Increase of space debris
 Threat of space debris
 Measures to solve
 Removal methods
 Concept model of microsatellite
 Characteristics of SDMR
 SDMR work briefing
 Concept of space debris removal system
 Main components of SDMR
 Key components of engineering
 Description of components and use
 Electrodynamic tether
 Release mechanism
 Reel mechanism
 Motion measurement and optical navigation
 Robot arm capture
 Advantages
 Disadvantages
 Conclusion
CONTENTS

4. INTRODUCTION
Since the number of satellites in Earth orbit is steadily increasing, space
debris also do and if they left unchecked, it will eventually pose a
serious hazard to near Earth space activities, and so effective measures
to are to be taken to mitigate it.
The Japan Aerospace Exploration Agency’s (JAXA) Institute of Aerospace
Technology is studying an active space debris removal system.
Conceptually, this consists of a small spacecraft (a micro-satellite
capable of piggyback launch) that transfers large debris objects that
occupy useful orbits to a disposal orbit. Electro-dynamic tether (EDT)
technology is being investigated as a high efficiency orbital transfer
system for this application. A small EDT package is being which could be
used to lower the orbit of the debris removal system without the need
for propellant.

5. What are space debris?
 Space debris, also known as orbital debris, space junk, and
space waste, is the collection of defunct objects in orbit around
Earth. This includes everything from spent rocket stages, old
satellites, fragments from disintegration, erosion, and collisions.
 Currently in 2000 km altitude, there are about 20,000 pieces of
debris larger than 5 cm are tracked and 3,00,000 pieces smaller
than 1 cm.
 Most space debris is less than 1 cm, including dust from solid
rocket motors, surface degradation products such as paint
flakes, and coolant released by RORSAT nuclear powered
satellites.

6. INCREASE IN DEBRIS
• As the launches
increased exponentially.
• Result of rockets upper
stages.
• Expired satellites.
• Cascading effect.
TILL NOW
Results of

7. • The increase in
collisions because of the
more objects
accumulating on space
orbits.
• The cascading effect
and the resulting
exponential increase is
difficult to slow down.
• If no counter measures
taken, collision rate will
increase to 25%.
IN FUTURE
INCREASE IN DEBRIS Results in

8. How they pose threat?
 Explosions of residual propellants and collisions between
satellite remnants or rocket upper stages can generate
large quantities of smaller debris, which greatly
increases the probability of collisions by a cascade
effect.
 Due to such cascade collisions, it is estimated that the
amount of space debris will increase an ever greater
rate from now on.
 Real threat to the television, communications, GPS and
also to the other satellites.
 And also to astronauts, launch vehicles, space flights
and make the low earth orbit applications impossible.
10%
1960 1990 2020 year
Probability of a catastrophic collision per year
P ~ N2, N ~ t

9.  The disposal of rocket upper stages and removal of satellites that have
reached the end of their Life.
 Designing space systems so that they do not become space debris; that
is, positive end-of-life processing of satellites.
 Processing existing debris that has no self-removal capability; that is, the
removal of large-size satellite remnants from economically and
scientifically useful orbits to disposal orbits.
 Providing a handle for the future satellites to facilitate easy removal.
HOW TO SOLVE THE PROBLEM

10. METHOD OF REMOVAL
 Earth-orbiting satellites typically occupy either
Low Earth Orbits (LEO) or geostationary orbits.
 Satellite remnants and rocket upper stages in
LEO may be removed by lowering their altitude to
650km or less, from where they will eventually re-
enter the atmosphere and burn up.
 Geostationary orbit altitude is too great to allow
this, so in this case, the effective disposal method
is further to raise the orbital altitude of satellite
remnants by 300km or more, to disposal orbits
that are of no practical use. After lowering the to a disposal orbit of
650 km or less they will remain in the
earth atmosphere for a 25 years and
eventually burn up.
Low Earth orbit
Disposal orbit

11. COMPOSITION
 Compact shape and low mass satellite body.
 Simple rendezvous system consists of a GPS
receiver, a star tracker and vision sensors.
 Small thrusters for maneuvering between orbits.
 Extensible light robot arm for debris capture.
 Debris removal by EDT package incorporated into
the root of the robot arm.

12. Characteristics of Space Debris Micro Remover
(SDMR)
ITEMS CHARACTERSTICS REMARKS
Size 700×700×600 mm3
Weight 140 kg Fuel: 25 kg
Power 100 W Average
Altitude control 3 Axes control Three wheels
Thrusters 1N x 8
Rendezvous sensors GPS receiver star tracker
stereo vision

14. CONCEPT OF SPACE DEBRIS REMOVAL SYSTEM

15. MAIN COMPONENTS OF SDMR

16. KEY COMPONENTS OF ENGINEERING
a) Electrodynamic Tether (EDT) for effective fuel free orbital transfer and propulsion.
b) Navigation to and around the debris object machine with vision/image processing.
c) A robotic extensible light arm to capture the debris object.

17. 1. Electrodynamic Tether or EDT package
 Enables the fuel free orbital transfer

18. 1.1 The conductive tether wire
 Aluminium braded with high-strength fibres
are used.
 This acts as the electron collector and
collects the electrons from ambient plasma.
1.2 The field emitter
 The array of carbon nanotube is used as the
emitter.

19. 2. Release mechanism
 Release mechanism was fabricated
using a double helical spring.
 This is activated using a light weight
flight hardware.
 This is used for releasing the tether.
3. Reel mechanism
 Uses a fixed-reel type extension
mechanism, which extends the tether
using the initial velocity.
 To slowed down the tether sufficiently
when it reaches the end of its
extension, and to produce no jerking
eddy current braking system is used.
 It is used in tether extension.

20. 4. Motion measurement and optical navigation
 Motion measurement is done using an on-board
sensor such as a star sensor, followed by radar
and an optical camera during the final approach.
 Based on this an algorithm has been developed
for estimating the motion (relative attitude and
relative position) of large pieces of space debris,
such as failed satellites.
 The algorithm uses a combination of stereo
vision and 3D model matching, and uses time
series of images to increase the reliability of the
relative attitude and position estimates.
 After the estimation of a target debris object,
the satellite will maneuver to match the target’s
rotational motion and will capture it.

21.  Capture of the target is
achieved through a extensible
robot arm.
 If the satellite possess a
dedicated handle, the robot
arm can be directly attached it.
 For ordinary case the robot
arm needs to grapple some part
of it - such as a payload
attachment fitting, a solar
panel mast, or an antenna
satellites.
5. Robot arm capture

22. • The micro satellite is compact, small in size and less in weight considering other
conventional artificial satellites.
• It can be launch with a piggyback launch vehicle along wit 6-10 small satellites.
• It uses propellant free propagation and no fuel for orbital transfer.
• All other energy requirements are met by solar panels, so no other fuel
required.
• Uses simple mechanism for removal.
• Minimised constructional cost and launch cost.

23. • Low life of tethers.
• Risk of tether collapse due to collision with other objects.
• The maximum tether extension is tested up to 20km.
• Removal can be done from low earth orbits and geostationary orbits.

24. • The removal of satellites from the orbit need the concern of owner of the
satellite and active removal programs rely on global consensus.
• The technical issue regarding an efficient orbital transfer and fuel free
propulsion are solved.
• Japan Aerospace Exploration Agency, is studying an active space debris
removal system using micro-satellites, and is investigating the
applicability of electro-dynamic tether technology as its high efficient
orbital transfer system.
• An optical motion measurement system, extensible folder arm and control
system for robotic debris capture are also under testing .

25. [1] S.Kibe,S.Kawamoto,F.Terui,S.Nishida,G.Gilardi,R&D of the active removal system for post-mission space
systems, in: Proceedings of the 54th International Astronautical Congress, IAC2003,Bremen,2003.
[2] J.R.Sanmartin,M.Martinez-Sanchez,E.Ahedo,Barewire anodes for electro dynamic tethers, Journal of Propulsion
and Power,1993.
[3] M.Oda,S.Nishida,et al., On-board local compensation on ETS-VII space robot teleoperation ,in: Proceedings of
the Advanced Intelligent Mechatronics, AIM’99,1999.
[4] S.Kitamura,Y.Okawa,etal.,Preliminary study on field emitter array cathodes for electro-dynamic tether
propulsion, in: 102 S.-I. Nishidaetal./Acta Astronautica 65(2009)95 –102 Proceedings of the Asian Joint Conference
on Propulsion and Power,Seoul,SouthKorea,2004.
[5] Y.Okawa, S.Kitamura,Y.Iseki, Preliminary testing of carbon-nanotube field emission cathodes for electro-
dynamic tethers, in: Proceedings of the Ninth Spacecraft Charging Technology Conference, 2005.
[6] S.Nishida, S.Kawamoto, F.Okawa, F.Terui, A.Nakajima, S. Kitamura, R&D status of the active removal system for
space debris, in: Proceedings of the International Astronautical Congress, IAC2005,Fukuoka,2005.
[7] S.Kawamoto, T.Makida, F.Sasaki,Y.Okawa, S.Nishida, Precise numerical simulations of electrodynamic tethers
for an active debris removal system, Acta Astronautica 59 (2006) 139–148.
[8] F.Terui, H.Kamimura, S.Nishida, Quick motion estimation of a large space debris object, in: Proceedings of the
International Symposium on Space Technology, ISTS2004, 2004.
[9] S.Nishida, T.Yoshikawa, Space debris capture by joint compliance controlled robot, in: Proceedings of the
Advanced Intelligent Mechatronics, AIM2003, Kobe, 2003.
References

26. THANKS