nano satellite

NANO-SATELLITE

Presented By

Shishu Priya Darshi

2007EEC08

20/10/2010 Shri Mata Vaishno Devi University,

Katra

Overview• Introduction

---- Definition

---- Motive

---- Working

• Technologies

---- Propulsion

---- Guidance, Navigation & Control

---- Command & Data Handling

---- Power System

---- Thermal

---- RF Communication

---- Mechanical / Structure

---- Instruments

---- Ground Systems

----- Autonomy

• Technology Transfer / Spinoff

• Conclusion

• References

•20/10/2010 Shri Mata Vaishno Devi University,

Katra

Introduction• Definition : Mass of satellite is 1-10kg including Propellant mass.

• Motives : Reduced mass results in significant decrease in cost of

satellite.

Less expensive to launch small component individually than

monolithic device

• Working : These are Spin stabilized – maximizes sun light and generate

5watt power that keep alive during eclipse period. ORThree axis stabilized (Snap 1 first nanosatellite of this type)

Placed in highly elliptical orbits of perigee radius (3 Re to

42Re) in 3Re increments

minimum spin rate 20rpm for sufficient stabilization

Sufficient onboard memory

to hold full orbit data.


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Technologies

• PropulsionChemical Propulsion:

1.Miniaturized Solid Propellant: – provide necessary

∆V for injection into final mission

2. Miniaturized Liquid Propellant- (Hydrazine or

advanced monopropellant ):- additional capability to

restart the engines for multiple burns.

Can be used for attitude control

3. Ultra low power cold gas thruster:- Low specific

impulse, simple and multiple-pulse capability.

4.Solid propellant gas generator:- can be used as ACS

thruster.

Electronic Propulsion:

1. Pulsed Plasma EP

2. Field Emission EP

Challenges for Propulsion

Low power ignition

Prevent flow chocking or premature combustion

Thruster array packaging


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Guidance Navigation & Control• Require for correct altitude measurement

• Include Sun sensor and horizon crossing indicator

• Requires nutation damper in conjection with thruster

• Concept of Navigation

1.Navigation using Magnetometer data:- assumes altitude is known. On

passing from low altitude region of orbit Magnetometer data can be

compared to onboard Magnetic field model and data is passed through

Kalman Filter.

2. TDRS Onboard Navigation System (TONS):- uses Doppler shift of

communication signal from TDRSS to generate onboard Navigation

solution.

3. Ground Onboard Navigation System(GONS):- It is currently being developed

4. GPS Onboard Navigation System:- To eliminate ground based ephemeris

generation. This allows for increase autonomy, and simpler more accurate

time resolution onboard the spacecraft.


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Command and Data Handling

• The major Technology requirement :-lightweight, low power electronics packaging; radiation hard, low

power processing platforms; high capacity, low power memory

systems; and radiation hard, reconfigurable, field

programmable gate arrays (RHrFPGA).

Packaging :- small volume and small footprint (6cm ₓ 6cm ₓ

variable high) Use of Technology-CMOS Ultra Low Power

Radiation Tolerant (CULPRiT) system on a chip, and “C&DH in

your Palm”

Morre‟s Trend

Reconfigurable Field Programmable Gate Array

(RHrFPGA) :-

replaces many logic function / circuit with a single die.

allows concurrent design by decoupling the logic design from the

module, shortens the design schedule, lowers the part count, and

eases rework.


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Power System• For small spinning setellite three solar cell connected in series. Each

section will generate 3.3 V and rotate into and out of sunlight as a unit.

• Dual or triple junction GaAs solar cells that give 18% conversion efficiency at end

of life (EOL), and assuming a more optimistic area factor of 85%, will result in

only 6.2 W at EOL

• Highly elliptical orbits in the ecliptic plane where the apogee velocity is very low

will cause a several hour eclipse during part of the year. However, only a 10° orbit

plane inclination relative to the ecliptic, will reduce the maximum eclipse period to

about one hour.

• Twelve AA size LiIon batteries meet the requirement and only weigh 480 grams.

Challenges before Power System:

Miniaturization of the power system electronics (PSE) to meet the weight

and size requirements of the nano-satellites is a considerable challenge

Solution of challenge :

by having a fixed electrical load and batteries provide the needed bus

regulation.

solar array regulator,

battery regulator, and

low voltage power converter20/10/2010 Shri Mata Vaishno Devi University,

Katra

ThermalThree Thermal Configuration:-

(1). Top and bottom of spacecraft is insulate, inside cylindrical solar arrays are

not insulated.-

Energy balance(Heat in = Heat out)

(2). The entire spacecraft is insulated, top and bottom as well as inside the solar

arrays, except for a radiator on top, sized to radiate the internal electrical

dissipation :-

Small overall energy balance

More sensitive to MLI properties

Eclipse performance improves.

(3). The internal equipment is thermally isolated as well as possible from an outside

shell” with a controllable two-phase heat transport device, which can be “shut

off” during earth shadows:-

Equipment is coupled to an external radiator only with two phase

heat transport device such as CPL or LHP.


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RF Communication• Low gain Omni antenna is used

• communications must take place near perigee, when the range is 3-

5 Earth radii.

• Inclusion of an onboard command receiver is highly desired.

• In future „Receiver on-chip‟ technology will be used.


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Mechanical / Structure

• diamond facesheet honeycomb panels can serve as a structure.

ORStructural Battery system:

It consists of a honeycomb panel whose core is filled

with the cells of a nickel-hydrogen battery (or other

flight qualified cell technology)

• Nano-satellite structure material are:

cast aluminum; cast aluminum-beryllium alloy; injection

molded plastic; fiber reinforced plastic; and flat stock

composite construction.


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Instruments

• Instruments Electronics :-

» Required to achieve high degree of

integration

• Instruments Software :-

» Designed to evaluate the onboard data and

adjust instrument data rates and modes to

efficiently capture the data of highest priority

• Instruments :-

Low energy particle detector

Magnetic Field Instruments

Instrument Sensor –(Mounted on deployable boom)


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Ground System

• Large number of satellite in constellation is a great challenge to the ground

system.

• Scheduler priorities the contacts, with the spacecraft in higher period orbit

getting priority.

• Except for commands to initiate the data downlink, the ground system will not

command the nano-satellites for normal operations

• Nano-satellites are autonomous :-

» Determination of orbit

» Scheduling the ground station

» Investigate anomalies on the spacecraft.


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Autonomy

• Nano-satellite autonomy will make use of onboard and ground-based

remote agents, with the overarching goal of maximizing the scientific return

from each satellite during the mission lifetime.

• the onboard agent will incorporate the capability to detect, diagnose and

recover from faults.

• Each spacecraft will include data in its telemetry stream on the health and

status of each subsystem and a history of commands autonomously issued

since the last ground contact


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TECHNOLOGY TRANSFER & SPINOFF

• Technology transfers, or spinoffs, have been and will remain an important

link between space organizations.

• Versatile propulsion technologies:-

miniaturized ignition systems and

ultra low power control valves

• The C&DH subsystem requires rugged, radiation tolerant, low power, and

lightweight electronics.

• miniaturized two-phase heat transfer technology

• communications coding techniques.


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CONCLUSION

• Miniaturized satellite with a maximum mass of 10 kg, and designed for a

two year mission life.

• Provisions for orbital maneuvers, attitude control, onboard orbit

determination, and command and data handling will be included

• Fully capable power and thermal systems, RF communications, multiple

sensors, and scientific instruments will be integrated on an efficient

structure.

• Nano-satellites developed for in-situ measurements will be spin-stabilized,

and those developed for remote measurements will be three-axis-stabilized.

• Autonomy both onboard the nano-satellites and at the ground stations will

minimize the mission operational costs for tracking and managing a

constellation.

• Key technologies being actively pursued include miniaturized propulsion

systems, sensors, electronics, heat transport systems, tracking techniques

for orbit determination, autonomy, lightweight batteries, higher efficiency

solar arrays, and advanced structural materials


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REFERENCES

• http://en.wikipedia.org/wiki/Miniaturized_satellite

• www.wisegeek.com/what-is-a-nanosatellite.htm

• www.tethers.com/Nanosats.htm

• www.plasma2.ssl.berkeley.edu/.../panetta.pdf

• Microsoft student Encarta 2007


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http://en.wikipedia.org/wiki/Miniaturized_satellite

http://www.wisegeek.com/what-is-a-nanosatellite.htm








http://www.tethers.com/Nanosats.htm

http://www.plasma2.ssl.berkeley.edu/.../panetta.pdf

http://www.plasma2.ssl.berkeley.edu/.../panetta.pdf

Thank you

20/10/2010 Shri Mata Vaishno Devi

University, Katra

nano satellite

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