The ResistoJet as a simple and cost-effective propulsion system for nano- and microsatellites

Transcription

1 1st IAA Latin American Symposium on Small Satellites Advanced Technologies and Distributed Systems March 7-10, 2017 IAA-LA The ResistoJet as a simple and cost-effective propulsion system for nano- and microsatellites Pablo Leslabay, Ricardo Lauretta, Patricio Pedreira Instituto Tecnológico de Buenos Aires ITBA Av. Eduardo Madero 399, C1106ACD, Buenos Aires, Argentina , leslabay@itba.edu.ar

2 Outline Propulsion requirements for the smaller SC ResistoJet properties Work at ITBA Further research at ITBA Conclusions

3 Propulsion systems for smaller SC Why considering an in-orbit propulsion subsystem: Orbit maneuvering Orbit maintenance Attitude control Constraints we have to deal with: Power OAP < 100W Mass < 15% of total SC Cost Volume Regulatory ITAR free, non-dangerous substances

4 Propulsion systems for smaller SC Considering the previous concepts, an ideal SC propulsion system should: Do not require great amounts of external energy to work there are only limited energy sources in space Have the highest ISP to hardware mass ratio maximize impulse while minimizing SC mass Produce rapid bursts of thrust to change orbital parameters efficient Hohmann transfers Produce low, controllable, steady streams of thrust for orbital maintenance repeatable control inputs Use simple, proven, plenty materials and processes Do not produce net torque for attitude control keep orbit stable Avoid using export controlled materials and substances

5 Propulsion systems for smaller SC So ideally we need What we got today is System Input power / Thrust [W/mN] Density * ISP [sec] Nitrogen cold gas 0 7 Hydrazine NO Resistojet 0,6 105 Butane ResJ 1 67,2 Hydrazine ResJ 1,9 304 Water ResJ 2, NH3 Arcjet 6,5 372 Hydrazine ArcJ NH3 ResJ Hall thruster Xe Ion PPT FEEP

6 ResistoJet properties ResistoJet: expand a pressurized and greatly overheated gas through a nozzle to increase its kinetical energy Heating occurs by conduction from an ohmic element External power source to overheat the gas limits the thrust, ranges 1-5 W/mN ISP up to 200, light system, but slightly complex heat transfer The gas source can be compressed, liquefied or self-pressurized Thrust depends only on mass flow, total impulse on reservoir size

7 ResistoJet properties Advantages Excellent power/thrust ratio (for non-chemical propulsion) Thrust in mn range Can easily use gas and liquid propellant Can fire continuously for long periods Able to avoid exotic/regulated materials and technology Limitations Upper temperature limit given by resistive material ISP limit Propulsion energy comes from the SC As every heat transfer system, difficult to produce small output bits

8 Work at ITBA BugSat ResistoJet (ITBA 2011)

9 Work at ITBA BugSat/NewSat Propulsion QuickFacts Type (over)heated gas - ResistoJet Propellant selected 99,0% n-butane Propellant mass 3500 gr Design ISP 120 sec Total impulse 4200 N-sec Operational temperature -10 / 0 ºC Storage temperature -50 / 35 ºC Flow control 12V electrovalve, On-Off Propellant title range 0 1 Nozzle design convergent-divergent inlet conditions 450ºC - 0.8bar exhaust conditions??ºc bar expansion ratio 60:1 Design trade offs Total elec power Thrust Min nozzle throat diam mass flow input pressure 60W 0.6mm 1bar(a) 100mN

10 Work at ITBA NewSat design (2014)

11 Work at ITBA and Satellogic System diagram

12 Work at ITBA and Satellogic EQM hardware at Satellogic

13 Further research at ITBA Planar nozzles for controllable microthrusters Difficulties in manufacturing small nozzles Ø <0.5mm Ability to control flow at fixed inlet pressure Very simple geometry Boundary layer effects found to be negligible No loss of flow axiality Correlation in CFD simulation and test framework

14 Further research at ITBA Microthrusters vacuum chamber 0.1Pa starting vacuum 35 Pa test vacuum 1mN thrust resolution Mass flow sensor 16x 10kHz channels - NI 0.1 m3 volume We like to test thrusters! Looking for opportunities to upgrade it

15 Further research at ITBA Thrust vector control Opportunity to use planar nozzles to also control thrust vector Couple or de-couple DOFs? Fresh Master thesis just showed not to be too ambitious Sealing difficulties Manufacturing tolerances Actuator complexity

16 Further research at ITBA The current system will be further developed

17 Future research at ITBA Start a program for H2 ResistoJet Best ISP possible for a ResistoJet w/o chemical decomposition Take advantage of pressurized electrolysis knowledge at ITBA transport water as propellant and prepare in-orbit! Use the generated O2 as a pumping and separation fluid Partially store energy in the gas, only overheating at propulsion Follow-on system burning H2 and O2 Transport water as propellant and prepare in-orbit Generate gases as power availability, fully store energy Control pressure and combustion Pumping and separation fluid, storage

18 Conclusions ResistoJets are a simple and robust propulsion system for low-cost small SC Low power requirements, able to use liquid and gas propellant Small size and low weight Low cost and complexity Tradeoff being the inherently low ISP Poorly deployable as ACS Not a sexy system ITBA started from scratch and achieved TRL8 in 3 years Extremely low budget involved ITAR free, no dangerous substances involved

19 Conclusions No one-fits-all solution ResistoJets can handle a large variety of propellants, select the right for your requirements ResistoJets can work with a wide power budget range, at an ISP premium Propellant storage and control systems can be made simple and lightweight, COTS Heating power control and distribution among elements is an important part of the solution

20 1st IAA Latin American Symposium on Small Satellites Advanced Technologies and Distributed Systems March 7-10, 2017 Thank you very much for your attention! The ResistoJet as a simple and cost-effective propulsion system for nano- and microsatellites Pablo Leslabay, Ricardo Lauretta, Patricio Pedreira Instituto Tecnológico de Buenos Aires ITBA Av. Eduardo Madero 399, C1106ACD, Buenos Aires, Argentina , leslabay@itba.edu.ar