1. NANO-SATELLITE Presented By ShishuPriyaDarshi 2007EEC08 20/10/2010 Shri Mata Vaishno Devi University, Katra

2. 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

3. 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. OR Three 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. 20/10/2010 Shri Mata Vaishno Devi University, Katra

4. Technologies Propulsion Chemical 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 Lowpower ignition Prevent flow chocking or premature combustion Thruster array packaging 20/10/2010 Shri Mata Vaishno Devi University, Katra

5. 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. 20/10/2010 Shri Mata Vaishno Devi University, Katra

6. 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. 20/10/2010 Shri Mata Vaishno Devi University, Katra

7. 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 converter 20/10/2010 Shri Mata Vaishno Devi University, Katra

8. Thermal Three 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. 20/10/2010 Shri Mata Vaishno Devi University, Katra

9. 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. 20/10/2010 Shri Mata Vaishno Devi University, Katra

10. Mechanical / Structure diamond facesheet honeycomb panels can serve as a structure. OR Structural 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. 20/10/2010 Shri Mata Vaishno Devi University, Katra

12. 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. 20/10/2010 Shri Mata Vaishno Devi University, Katra

13. 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 20/10/2010 Shri Mata Vaishno Devi University, Katra

15. miniaturized two-phase heat transfer technology

16. communications coding techniques.20/10/2010 Shri Mata Vaishno Devi University, Katra

17. 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 20/10/2010 Shri Mata Vaishno Devi University, Katra

18. 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 20/10/2010 Shri Mata Vaishno Devi University, Katra

19. Thank you 20/10/2010 Shri Mata Vaishno Devi University, Katra