Products from NASA's in-space propulsion technology program applicable to low-cost planetary missions

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Products from NASA’s in-space propulsion technology programapplicable to low-cost planetary missions

David J. Anderson a,n, Eric Pencil a, Daniel Vento a, Todd Peterson a, John Dankanich b,David Hahne c, Michelle M. Munk c

a NASA Glenn Research Center, 21000 Brookpark Road, S Cleveland, OH 44135, USAb Gray Research Inc., 21000 Brookpark Road, Cleveland, OH 44135, USAc NASA Langley Research Center, 1 North Dryden Street, Hampton, VA 23681, USA

a r t i c l e i n f o

Article history:

Received 6 January 2012

Accepted 3 July 2012

Keywords:

Electric propulsion

Chemical propulsion

Aerocapture

Entry vehicles

Trajectory tools

65/$ - see front matter Published by Elsevier

x.doi.org/10.1016/j.actaastro.2012.07.006

espondence to: NASA Glenn Research Cente

leveland, OH 44135, USA. Tel.: þ1 216 4338

216 4338660.

ail addresses: [email protected] (D.J

[email protected] (E. Pencil), Daniel.M.Vento@na

[email protected] (T. Peterson),

[email protected] (J. Dankanich),

[email protected] (D. Hahne),

[email protected] (M.M. Munk).

e cite this article as: D.J. Anderson, ew-cost planetary missions, Acta Ast

a b s t r a c t

Since September 2001, NASA’s In-Space Propulsion Technology (ISPT) program has been

developing technologies for lowering the cost of planetary science missions. Recently

completed is the high-temperature Advanced Material Bipropellant Rocket (AMBR)

engine providing higher performance for lower cost. Two other cost saving technologies

nearing completion are the NEXT ion thruster and the Aerocapture technology project.

Under development are several technologies for low-cost sample return missions. These

include a low-cost Hall-effect thruster (HIVHAC) which will be completed in 2011,

light-weight propellant tanks, and a Multi-Mission Earth Entry Vehicle (MMEEV). This

paper will discuss the status of the technology development, the cost savings or

performance benefits, and applicability of these in-space propulsion technologies to

NASA’s future Discovery, and New Frontiers missions, as well as their relevance for

sample return missions.

Published by Elsevier Ltd.

1. Introduction

NASA’s Science Mission Directorate (SMD) missionsseek to answer important science questions about ourplanet, the Solar System and beyond. To meet NASA’sfuture mission needs, the goal of the ISPT program is thedevelopment of new enabling propulsion technologiesthat cannot be reasonably achieved within the cost orschedule constraints of mission development timelines.

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Since 2001, the In-Space Propulsion Technology (ISPT)program has been developing in-space propulsion tech-nologies that will enable and/or benefit near and mid-term NASA robotic science missions by significantlyreducing cost, mass, and/or travel times. ISPTs will helpdeliver spacecraft to SMD’s destinations of interest.

An objective of ISPT is to develop products that realizenear-term and mid-term benefits. The program primarilyfocuses on technologies in the mid TRL range (TRL 3 to 6þrange) that have a reasonable chance of reaching maturityin 4–6 years. The objective is to achieve technology readi-ness level (TRL) 6 and reduce risk sufficiently for missioninfusion. The project strongly emphasizes developingpropulsion products for NASA flight missions that will beultimately manufactured by industry and made equallyavailable to all potential users for missions and proposals.

The ISPT program is currently developing technology infour areas. These include Advanced Chemical and ElectricPropulsion, Entry Vehicle Technologies, Sample Return

SA’s in-space propulsion technology program applicable://dx.doi.org/10.1016/j.actaastro.2012.07.006

www.elsevier.com/locate/actaastro

www.elsevier.com/locate/actaastro

dx.doi.org/10.1016/j.actaastro.2012.07.006



mailto:[email protected]











D.J. Anderson et al. / Acta Astronautica ] (]]]]) ]]]–]]]2

Propulsion, and Systems/Mission Analysis. These in-spacepropulsion technologies are applicable, and potentiallyenabling for future NASA Discovery, New Frontiers, andsample return missions currently under consideration, aswell as having broad applicability to potential Flagshipmissions. For more background on ISPT, please see Refs.[1] and [2].

Fig. 1. Illustration of the aerocapture maneuver.

2. Technology relevance

The ISPT priorities and products are tied closely to thescience roadmaps, the SMD’s science plan, and the dec-adal surveys. ISPT emphasizes technology developmentwith mission pull. In 2006, the Solar System Exploration(SSE) Roadmap [3] identified technology developmentneeds for Solar System exploration, and described trans-portation technologies as highest priority, with the high-est priority propulsion technologies being electricpropulsion and aerocapture. Excerpts from the sciencecommunity are discussed in Ref. [4]. Initially, ISPT’sresponsibility was to develop technologies for Flagshipmissions, but in 2006 the focus evolved to technologyinvestments that would be applicable to New Frontiersand Discovery competed missions. Aerocapture (the useof aerodynamic drag for orbit capture) and electric pro-pulsion continued to be a priority, but the refocus activityalso recommended a long-life lower-power Hall system.

Looking towards ISPT’s future, the 2011 PlanetaryScience Decadal Survey [5] was released March 2011and provides guidance for ISPT’s future technology invest-ments. The Decadal Survey made many references toISPTs such as aerocapture, NEXT, AMBR, astrodynamics,mission trajectory and planning tools. This Decadal Sur-vey is validating the technology investments ISPT hasmade over the last 10 years, but also provides ISPT with anew focus for the next 10–20 years.

The Decadal Survey supported NASA developing amulti-mission technology investment program that will‘‘preserve its focus on fundamental system capabilitiesrather than solely on individual technology tasks.’’ TheDecadal Survey highlighted the NEXT system develop-ment as an example of this ‘‘integrated approach’’ of‘‘advancement of solar electric propulsion systems toenable wide variety of new missions throughout the solarsystem.’’ The Decadal Survey recommends ‘‘making simi-lar equivalent systems investments’’ in the advancedUltraflex solar array technology and aerocapture. TheDecadal Survey discussed the importance of developingthose system technologies to TRL 6.

One recommendation in the Decadal Survey was for ‘‘abalanced mix of Discovery, New Frontiers, and Flagshipmissions, enabling both a steady stream of new discov-eries and the capability to address larger challenges likesample return missions and outer planet exploration.’’These broad mission needs would require a balanced setof multi-mission technologies and integrated systemcapabilities. The Survey acknowledges that a ‘‘robustDiscovery and New Frontiers program would be substan-tially enhanced by such a commitment to multi-missiontechnologies.’’

Please cite this article as: D.J. Anderson, et al., Products from NAto low-cost planetary missions, Acta Astronautica (2012), http

3. Results and discussion

3.1. Aerocapture

Aerocapture is the process of entering the atmosphereof a target body to practically eliminate the chemicalpropulsion requirements of orbit capture. Aerocapture isthe next step beyond aerobraking, which relies on multi-ple passes high in the atmosphere using the spacecraft’sdrag to reduce orbital energy. Aerobraking has been usedat Mars on multiple orbiter missions. Aerocapture, illu-strated in Fig. 1, maximizes the benefit from the atmo-sphere by capturing into orbit in a single pass. Aerocapturerepresents a major advance over aerobraking techniques,by flying at a lower altitude where the atmosphere is moredense. Key to successful aerocapture is accurate arrivalstate knowledge, validated atmospheric models, sufficientvehicle control authority (i.e. lift-to-drag ratio), and robustguidance during the maneuver. A lightweight thermalprotection system and structure maximizes the aerocap-ture mass benefits.

Executing the aerocapture maneuver itself enables thegreat mass savings over other orbital insertion methods.If the hardware subsystems are not mass efficient, or ifperformance is so poor that additional propellant is neededto adjust the final orbit, the benefits can be significantlyreduced. ISPT efforts in aerocapture subsystem technolo-gies are focused on improving the efficiency and number ofsuitable alternatives for aeroshell structures and ablativethermal protection systems (TPS). These include develop-ment of families of low and medium density (14–36 lbs/ft3)TPS and the related sensors, development of a carbon–carbon rib-stiffened rigid aeroshell, and high temperaturehoneycomb structures and adhesives. Developmentoccurred on inflatable decelerators through concept defi-nition and initial design and testing of several inflatabledecelerator candidates. Finally, progress was madethrough improvement of models for atmospheres, aero-thermal effects, and algorithms and testing of a flight-likeguidance, navigation and control (GN and C) system.

Aerocapture has shown repeatedly in detailed analysesto be an enabling or strongly enhancing technology for





Fig. 2. Basic MMEEV architecture.

D.J. Anderson et al. / Acta Astronautica ] (]]]]) ]]]–]]] 3

several atmospheric targets. The ISPT project team con-tinues to mature aerocapture component in preparationfor a flight demonstration. Rapid aerocapture analysistools are being developed and made available to a wideuser community. The TPS materials developed throughISPT enhance a wide range of missions by reducing themass of entry vehicles. The remaining gaps for technologyinfusion are efficient TPS for Venus, high-speed Earthreturn, and Neptune. All of the other component subsys-tems for an aerocapture vehicle are currently at or fundedto reach TRL 6 in the next year. This assessment oftechnology readiness is detailed in Ref. [6]. The structuresand TPS subsystems as well as the aerodynamic andaerothermodynamic tools and methods can be applied tosmall-scale entry missions even if the aerocapture man-euver is not utilized.

The Aerocapture system cannot reach TRL 6 withoutspace flight validation, because it is impossible to matchthe flight environment in ground facilities. This validationcan be accomplished by utilizing Aerocapture on a sciencemission, or by a dedicated space flight validation experi-ment. NASA’s Science Mission Directorate has incentivizedthe use of Aerocapture in its recent Discovery Announce-ment of Opportunity. Because a Discovery mission utilizingAerocapture was not selected, Aerocapture will seek otheropportunities to be validated in space. A space flightvalidation is expensive, but the costs will be recouped veryquickly if just one mission’s launch vehicle cost is reducedas a result of the lower mass requirement enabled byAerocapture. The validation immediately reduces the riskto the first user and matures the maneuver for applicationto multiple, potentially lower-cost, missions to Titan, Mars,Venus, and Earth. Moreover, once Aerocapture is proven areliable tool, it is anticipated that entirely new missionswill become possible. Additional information on Aerocapturetechnology developments can be found in the Discoveryprogram library [7]. Using Aerocapture, significant costbenefits are realized for multiple missions. When the overallsystem mass is reduced, the mission can utilize a smallerlaunch vehicle, saving tens of millions of dollars. Detailedmission assessment results can be found in the Aerocapture-related references in Ref. [2].

3.2. Multi-mission earth entry vehicle (MMEEV)

The Multi-Mission Earth Entry Vehicle (MMEEV) is aflexible design concept which can be optimized or tai-lored by any sample return mission, including lunar,asteroid, comet, and planetary (e.g. Mars), to meet thatmission’s specific requirements. Based on the MarsSample Return (MSR) Earth Entry Vehicle (EEV) design,due to planetary protection requirements, the MMEEV isdesigned to be the most reliable space vehicle ever flown.The MMEEV concept provides a logical foundation thatany sample return mission can build upon in optimizingan EEV design that meets their specific needs. By lever-aging common design elements, this approach can sig-nificantly reduce the risk and associated cost indevelopment across all sample return missions. It alsoprovides significant feed-forward risk reduction in the


form of technology development, testing, and even flightexperience, for an eventual MSR implementation.

The current MMEEV parametric configuration is pre-sented in Fig. 2 (basic vehicle architecture). Because eachindividual sample return mission may have a unique setof performance metrics of highest interest, the goal is toprovide a qualitative performance comparison across aspecified trade space. Each sample return mission canselect the most desirable design point to begin a moreoptimized design.

Continued development of the MMEEV models isplanned to include: more sophisticated parametric con-figuration. This includes payload accommodation models,higher fidelity impact dynamics model (e.g. finite-elementmodel), updated aerodynamics models based on ground(e.g. wind tunnel and ballistic range) testing as well asComputational Fluid Dynamics (CFD) analysis, and highfidelity TPS mass/thickness sizing models for additionalcandidate TPS materials. MMEEV performance studies willcontinue with the eventual integration of the MMEEVmodels into a prototype EDL analysis tool. This tool wasoriginally developed in support of ISPT aerocapture stu-dies, and is currently being developed to support missionstudies to any celestial body with an atmosphere.

The biggest challenge for any space vehicle, including theMMEEV, is to adequately prove the reliability of the com-ponents, subsystems, and the flight system as a whole. Thecurrent estimate to develop the EEV technology for MSR toTRL 6 is approximately $41 million. This does not include adedicated flight test, which many experts agree is needed toachieve the 10�6 probability of failure, because the entryflight environment cannot be replicated in ground-basedfacilities. One way to achieve a flight validation for littleextra cost to NASA is to use the MMEEV design concept, orat least the major components of the design, in samplereturn missions likely to fly prior to MSR such as NewFrontiers or Discovery. NASA Headquarters managers andthe In-Space Propulsion Technology (ISPT) team are pursu-ing this approach, but currently there are no manifestedmissions that are planning to use an MSR EEV design.

3.3. Solar electric propulsion (SEP)

Solar Electric Propulsion (SEP) enables missions requiringlarge post-launch DV. SEP has applications to rendezvous





Fig. 3. NEXT thermal vacuum testing at JPL.


and sample-return missions to small bodies and fast trajec-tories towards the outer planets.

Electric propulsion is both an enabling and enhancingtechnology for reaching a wide range of targets. The highspecific impulse, or efficiency of electric propulsion sys-tem, allows direct trajectories to multiple targets that areinfeasible using chemical propulsion. The technologyallows for rendezvous missions in place of fly-bys, andas planned in the Dawn mission can enable multipledestinations.

This technology offers major performance gains, onlymoderate development risk, and has significant impact onthe capabilities of new missions. Current plans includecompletion of the NASA’s Evolutionary Xenon Thruster(NEXT) Ion Propulsion System target at Flagship, NewFrontiers and demanding Discovery missions.

The GRC-led NEXT project was competitively selectedto develop a nominal 40 cm gridded-ion electric propul-sion system [2]. The objectives of this development wereto improve upon the State-of-the-Art (SOA) NASA SolarElectric Propulsion Technology Application Readiness(NSTAR) system flown on Deep Space-1 to enable flagshipclass missions by achieving the performance character-istics listed in Table 1.

The ion propulsion system components developedunder the NEXT task include the ion thruster, thepower-processing unit (PPU), the feed system, and agimbal mechanism. The NEXT project is developing pro-totype-model (PM) fidelity thrusters through AerojetCorporation. In addition to the technical goals, the projecthas the goal of transitioning thruster-manufacturing cap-ability with predictable yields to an industrial source. Toprove out the performance and life of the NEXT, a series oftests have, or are being, performed. The NEXT PM thrustercompleted a short duration test in which overall ion-engine performance was steady with no indication ofperformance degradation. A NEXT PM thruster has alsopassed qualification level environmental testing (Fig. 3).As of November 30, 2011 the Long Duration Test (LDT) ofthe NEXT engineering model (EM) thruster achieved over664 kg xenon throughput, 25.2�106 N s of total impulse,and 438,000 h at multiple throttle conditions. The NEXTLDT wear test demonstrates the largest total impulse everachieved by a gridded-ion thruster. ISPT funding for thethruster life test continues through FY12 with the aim ofdemonstrating up to 750 kg of xenon throughput [8].

The NEXT has clear mission advantages for verychallenging missions. For example, the Dawn DiscoveryMission only operates one NSTAR thruster at a time, butrequires a second thruster for throughput capability. For

Table 1Performance comparison of NSTAR and NEXT ion thrusters.

Characteristic NSTAR (SOA) NEXT

Max. thruster power (kW) 2.3 6.9

Max. thrust (mN) 91 236

Throttle range (Max./Min. thrust) 4.9 13.8

Max. specific impulse (s) 3120 4190

Total impulse (�106 N s) 45 418

Propellant throughput (kg) 200 750


the same mission, the NEXT could deliver mass, equiva-lent to doubling the science package, with only a singlethruster. Reducing the number of thrusters reduces pro-pulsion system complexity and spacecraft integrationchallenges. The NEXT can enable a lower cost implemen-tation through eliminating system complexity. Compar-isons between the State-of-the-Art (SOA) NSTAR thrusterand the NEXT are shown in Table 1.

The missions that are improved through the use of theNEXT are those requiring significant post-launch DV, suchas sample returns, highly inclined, or deep-space bodyrendezvous missions. The comet sample-return missionwas studied for several destinations because of its highpriority within the New Frontiers mission category. Elec-tric propulsion enables a much wider range of feasibletargets. Specifically for Temple 1 in Ref. [2], the NSTARthruster is able to complete the mission, but requireslarge solar arrays and four or five thrusters to deliver therequired payload. NEXT would be able to deliver 10%more total mass and require half the number of thrusters.

Additional information on the NEXT system can befound in the NEXT Ion Propulsion System InformationSummary in the New Frontiers and Discovery programlibraries [7–9].

3.4. Electric propulsion for sample return and discovery-

class missions

ISPT is investing in Sample Return Propulsion technol-ogies for applications such as Earth-Return Vehicles forlarge and small bodies. The first example leverages thedevelopment of a High-Voltage Hall Accelerator (HIVHAC)thruster into a lower-cost electric propulsion system [1].HIVHAC is the first NASA electric propulsion thrusterspecifically designed as a low-cost electric propulsionoption. It targets Discovery and New Frontiers missionsand smaller mission classes. The HIVHAC thruster doesnot provide as high a maximum specific impulse as NEXT,but the higher thrust-to-power and lower power require-ments are suited for the demands of some Discovery-classmissions and sample return applications. Advancementsin the HIVHAC thruster include a large throttle range from






0.3–3.5 kW allowing for a low power operation. It resultsin the potential for smaller solar arrays at cost savings,and a long-life capability to allow for greater total impulsewith fewer thrusters. It allows for cost benefits with areduced part count in less-complex and lower-cost pro-pulsion system.

Wear tests of the NASA-103M.XL thruster validated anddemonstrated a means to mitigate discharge channel erosionas a life limiting mechanism in Hall thrusters. The thruster,shown in Fig. 4, operated in excess of 5500 h (115 kg ofxenon throughput) at a higher specific impulse (thrusteroperating voltage) as compared to SOA Hall thrusters.

Components for two Engineering Model (EM) thrusterswere designed and fabricated. Preliminary performancemapping of the EM thruster at various operating condi-tions was performed at NASA Glenn Research Center(GRC) [1]. In the future, the test sequence will includeperformance acceptance tests, environmental tests and along duration test in FY11 and FY12. Current plans includethe design, fabrication and assembly of a full Hall propul-sion system, but are pending final approval to proceed.

In addition to the thruster development, the HIVHACproject team is evaluating power-processing unit (PPU)and xenon-feed system (XFS) development options thatwere sponsored by other projects but can apply directly toa HIVHAC system. The goal is to advance the TRL level of aHall propulsion system to level 6 in preparation for a firstflight.

The functional requirements of a HIVHAC PPU areoperation over a power throttling range 300–3800 W,over a range of output voltages between 200 and 700 V,and output currents between 1.4 and 5 A as the inputvaries over a range 80–160 V. A performance map acrossthese demanding conditions was generated for one can-didate option [1] that is being developed through theNASA SBIR Program. Beyond conventional feed systemoptions, one option for feed systems that was demon-strated with the Hall thruster is the advanced xenon feedsystem, developed by VACCO.

For the Near-Earth Object (NEO) mission evaluation,the HIVHAC thruster system delivered over 30% more

Fig. 4. HIVHAC Thruster Engineering Model.


mass than the NSTAR system. The performance increaseaccompanied a cost savings of approximately 25% overthe SOA NSTAR system. The Dawn mission was evaluated,and the expected HIVHAC Hall thruster delivered approxi-mately 14 percent more mass at substantially lower costthan SOA. Decreasing the solar array provided equivalentperformance at even greater mission cost savings [1].

The second technology example of a Sample ReturnPropulsion Technology is the BPT-4000 hall thrusterdevelopment. ISPT invested in a life-test extension of thethruster to improve total impulse demonstrated capabil-ities. Under evaluation is the operation of this thrusterdesign at higher operating voltages, which improve thrus-ter specific impulse. There are mission studies that indi-cate that BPT-4000 is directly applicable to ERV andDiscovery-class missions.

3.5. Propulsion component technologies

ISPT invests in the evolution of component technologiesthat offer significant performance improvements withoutincreasing system level risk. Two component technologiescurrently receiving investments are xenon feed systemsand Ultra-Lightweight Tank Technology (ULTT).

ISPT is investing in the Advanced Xenon Feed System(AXFS) for electric propulsion systems [1]. The feedsystem is designed for an increased reliability combinedwith a decrease in system mass, volume, and cost ascompared to SOA flight systems and comparable TRL 6technology. The final development module, the pressurecontrol module (PCM), was completed in 2007. The NavalResearch Laboratory (NRL) completed functional andenvironmental testing of the VACCO PCM in Septemberof 2008. Following the environmental testing, the PCMwas integrated with the FCMs and an integrated AXFSwith controller was delivered to the project. NASA GRCcompleted hot-fire testing of the AXFS with the HIVHACHall thruster successfully demonstrating hot-fire opera-tion using closed-loop control with downstream pressurefeedback and with the Hall thruster discharge current.Follow-on testing will determine the viability of the AXFSto perform single-stage, single module, control from high-pressure xenon directly to a thruster.

The AXFS technology is ready for transition into aqualification program. It achieves its objective [1] bydemonstrating accurate xenon control with significantsystem reduction in mass and volume through the useof integrated modules for low-cost control options and/orreliability beyond practical SOA technology implementa-tion. The resultant feed system represents a dramaticimprovement over the NSTAR flight-feed system andrepresents an additional 70% reduction in mass, 50%reduction in footprint, and 50% reduction in cost overthe baseline NEXT feed system at TRL 6. The projectsuccessfully completed the integrated system testingand advanced the modules to TRL 6 [2]. The Hall moduleis shown in Fig. 5.

ISPT previously invested in Ultra-Lightweight TankTechnology (ULTT), which led to flight tanks sized forbut ultimately not used on the Mars Exploration Rover(MER) mission. The ULTT efforts in the past focused on





Fig. 5. VACCO Xenon Flow Control Module.

Fig. 6. AMBR engine test article.


manufacturability and non-destructive evaluation of thelightweight tanks. Previous work on the lightweightpropellant tanks will continue with general applicabilityto all future planetary spacecraft. The mass savings, andresultant cost impacts, could be significant for the tankdevelopments, because tanks are one of the largestspacecraft bus components. The ISPT project is currentlyplanning to develop and qualify positive expulsiveultra-lightweight tanks specifically for the MSL Sky Crane.These tanks can offer mass savings on the order of 24–30 kg,dependent on the final tank wall thickness, and increase thelanded mass capability of Sky Crane for a relatively low costper kilogram. While the tanks will be qualified for the SkyCrane application, the technology will be broadly applicablefor a wide range of future low-cost science missions.

3.6. Advanced chemical propulsion

ISPT’s approach to the development of chemical propul-sion technologies is primarily the evolution of subcompo-nent technologies that offers significant performanceimprovements, with minimal risk. The mission benefits inadvanced chemical propulsion are synergistic, and thecumulative effects have tremendous potential. The infusionof the individual subsystems separately provides reducedrisk, or combined, provides considerable payload massbenefits. Ref. [10] has a thorough description of thecomplete Advanced Chemical Propulsion effort that wasconcluded in 2009.

The single largest investment within the advancedchemical propulsion technology area was the AdvancedMaterials Bipropellant Rocket (AMBR) engine (Fig. 6),which was awarded, through a competitive process, toAerojet Corporation in FY2006. The AMBR engine is a hightemperature thruster that aimed to address cost andmanufacturability challenges of using iridium coated rhe-nium chambers. The project [2] included the manufactureand hot-fire tests of a prototype engine demonstratingincrease performance and validating new manufacturingtechniques. Performance testing was conducted on the


AMBR engine in October 2008 and February 2009 withlong duration testing in June 2009. The thruster demon-strated an Isp of 333 s at 141 lb f thrust, which is thehighest ever achieved for hydrazine/NTO (nitrogen tetr-oxide) propellant combination. Vibration, shock, and longduration testing was completed on the AMBR engine toraise its TRL to 6 [11]. Additional information is found inthe AMBR information summary in the New Frontiers andDiscovery program libraries [7,12].

3.7. Systems/mission analysis

Systems analysis is critical prior to investing in tech-nology development. In today’s environment, advancedtechnology must maintain its relevance through missionpull. The second focus of the systems analysis project areais the development and maintenance of tools for themission and systems analyses. Improved and updatedtools are critical to clearly understand and quantifymission and system level impacts of advanced propulsiontechnologies. Having a common set of tools increasesconfidence in the benefit of ISPT products both for mis-sion planners as well as for potential proposal reviewers.Tool development efforts were completed on the Low-Thrust Trajectory Tool (LTTT) and the Advanced ChemicalPropulsion System (ACPS) tool.

Low-thrust trajectory analyses are critical to the infu-sion of new electric propulsion technology. Low-thrusttrajectory analysis is typically more complex than chemi-cal propulsion solutions during the preliminary missiondesign phase. Some of the heritage tools prove to beextremely valuable, but cannot perform direct optimiza-tion and require good initial guesses by the users. Thisleads to solutions difficult to verify quickly and indepen-dently. The ability to calculate the performance benefit ofcomplex electric propulsion missions is intrinsic to thedetermination of propulsion system requirements. TheISPT office invested in multiple low-thrust trajectory toolsthat independently verify low thrust trajectories at var-ious degrees of fidelity.

ISPT products can ease technology infusion because of theability for the user community to rapidly and accuratelyaccess the mission level impacts. In addition to the toolscurrently available, the ISPT project sponsored the develop-ment of an Aerocapture quicklook tool to allow usersan opportunity to quantify mission benefits of an aerocapturesystem including mass properties and geometry. Every effort






will be made to have these tools validated, verified, and madepublicly available. Instructions to obtain the tools currentlyavailable are provided on the ISPT project website [13].

4. Conclusion and future Plans

NASA recognizes that it is desirable to fly new tech-nologies that enable new scientific investigations or toenhance an investigation’s science return. The SSE Road-map states that NASA will strive to maximize the payofffrom its technology investments, either by enablingindividual missions or by enhancing classes of missionswith creative solutions. Discovery, New Frontiers, andFlagship missions potentially provide opportunities toinfuse advanced technologies developed by NASA, andadvance NASA’s technology base and enable a broader setof future missions.

To benefit from its technology investments, NASAprovided incentives for infusion of new technologicalcapabilities that it had developed in the most recentNew Frontiers and Discovery competed mission solicita-tions. The incentives for NEXT, AMBR, Aerocapture, andthe Advanced Stirling Radioisotope Power System (ASRG)were in the form of increases to the cost cap for themission, or providing the ASRG as Government FurnishedEquipment (GFE). The Decadal Survey states ‘‘these tech-nologies continue to be of high value to a wide variety ofsolar system missions’’ and that ‘‘NASA should continue toprovide incentives for these technologies until they aredemonstrated in flight.’’ The 2011 Planetary DecadalSurvey strongly supported continuing to incentivize thesetechnologies until they are flown [5]. As funding andpriorities allow, ISPT will strive to maintain the capabil-ities associated with NEXT, AMBR, and aerocapture.

Beyond the New Frontiers and Discovery opportu-nities, ISPT continues to seek opportunities to infuseNEXT, AMBR, Aerocapture, and its other technologies intoa wide range of possible future mission opportunities. TheISPT project office and NEXT team personnel are activelysupporting various flagship science definition team (SDT)studies. See the ISPT Overview paper in the 2011 IEEEAerospace Conference for more details regarding thesestudies [1,2]. ISPT will continue to help in identifying thetechnology development that is required to accomplishthe future missions being contemplated.

The ISPT program is investing in technologies to enhanceor enable low-cost planetary science mission opportunities.The AMBR engine and Aerocapture investments are avail-able for mission infusion. The NEXT ion propulsion system isplanned to reach completion with the next year. The ISPTprogram is also progressing on a low-cost electric propul-sion alternative. The program will continue to incentivizethese technologies; reducing cost and risk of infusion tofuture low-cost mission opportunities.

Acknowledgments

The results and findings presented here are based onwork funded by NASA’s Science Mission Directorate (SMD).


The ISPT program is managed out of the Glenn ResearchCenter for SMD’s Planetary Sciences Division (PSD).

References

[1] D.J. Anderson, J. Dankanich, D. Hahne, E. Pencil, T. Peterson, M.Munk, Sample Return Propulsion Technology Development underNASA’s ISPT Project, 2011 IEEE Aerospace conference, Paper #1115,March 2011.

[2] D.J. Anderson, E. Pencil, T. Peterson, J. Dankanich, M. Munk,In-Space Propulsion Technology Products for NASA’s Future Scienceand Exploration Missions, 2011 IEEE Aerospace conference, Paper#1114, March 2011.

[3] 2006 Solar System Exploration Roadmap for NASA’s Science Mis-sion Directorate, September 2006.

[4] D.J. Anderson, E. Pencil, L. Liou, J. Dankanich, M. Munk, T. Kremic,The NASA In-Space Propulsion Technology Project, Products, andMission Applicability, 2009 IEEE Aerospace conference, Paper#1176, March 2009.

[5] Vision and Voyages for Planetary Science in the Decade 2013–2022,The National Academies Press, /http://www.nap/eduS, 2011.

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[8] NASA’s Evolutionary Xenon Thruster (NEXT) Ion Propulsion systemInformation Summary, New Frontiers Program Library Web site/http://newfrontiers.larc.nasa.gov/NFPL.htmlS, August 2008.

[9] New Frontiers Program Library Web site, /http://newfrontiers.larc.nasa.gov/NFPL.htmlS.

[10] L. Liou, J. Dankanich, L. Alexander, NASA In-Space AdvancedChemical Propulsion Development in Recent Years, 2010 IEEEAerospace Conference, Big Sky, MT, March 6–13, 2010.

[11] S. Henderson, C. Stechman, K. Wierenga, S. Miller, L. Liou, L.Alexander, J. Dankanich, Performance Results for the AdvancedMaterials Bipropellant Rocket (AMBR) Engine, AIAA 2010-6883,46th JPC, Nashville, TN, July 25–28, 2010.

[12] Advanced Material Bi-propellant Rocket (AMBR) Information Sum-mary, New Frontiers Program Library Web site /http://newfrontiers.larc.nasa.gov/NFPL.htmlS, August 2008.

[13] NASA ISPT Web site /http://spaceflightsystems.grc.nasa.gov/Advanced/ScienceProject/ISPT/LTTT/S.

David Anderson is a program manager in theScience Project Office at the NASA GlennResearch Center (GRC), and has been a NASAemployee for over 22 years. He is currentlythe Acting Program Manager for the In-SpacePropulsion Technology (ISPT) program, and isthe SBIR Spacecraft and Platform SubsystemsTopic Manager. Formerly, he managed theadvanced Radioisotope Power System (RPS)efforts at NASA GRC, was active with newbusiness development and proposal develop-ment activities. He has a B.S. in Aerospace
Engineering from the University of Cincinnati
and an M.S. in Engineering Management from the Cleveland StateUniversity.

Eric Pencil is Propulsion Projects Area Man-ager for the In-Space Propulsion TechnologyOffice at NASA Glenn Research Center. He isresponsible for the management and execu-tion of the electric propulsion developmenttasks for NASA Science missions. Previouslyhe worked as a project/research engineer inthe electric propulsion research group inwhich he worked on various electric propul-sion technologies at varying stages of matur-ity from basic research to flight hardware.


http://www.nap/edu

http://discovery.larc.nasa.gov/dpl.html

http://discovery.larc.nasa.gov/dpl.html

http://newfrontiers.larc.nasa.gov/NFPL.html





http://spaceflightsystems.grc.nasa.gov/Advanced/ScienceProject/ISPT/LTTT/

http://spaceflightsystems.grc.nasa.gov/Advanced/ScienceProject/ISPT/LTTT/





Daniel Vento is a project manager in theScience Project Office at the Glenn ResearchCenter. He is the Integration Manager forISPT. With 32 years experience at GRC, Danhas an an extensive background in propul-sion, propellant management, launch vehi-cles and space flight projects. Dan has aBachelor of Mechanical Engineering for Cle-veland State University as well as an MSMEfrom the University of Toledo.

Todd Peterson is a project manager in theAdvanced Capabilities Project Office at theNASA Glenn Research Center (GRC). Withover 26 years of space flight project experi-ence at NASA GRC, he has extensive propul-sion, power and communication systemproject management experience in humanand robotic space flight projects (Space Sta-tion, Shuttle/Mir, Deep Space-1, Earth Obser-ver-1, Lunar Reconnaissance Orbiter) anddevelopment projects (electric propulsion,chemical propulsion, photovoltaic and
dynamic power systems, microgravity
research). He has a B.S. in Mechanical Engineering from the Universityof Akron and an M.S. in Mechanical Engineering from Cleveland StateUniversity.

John Dankanich is a Gray Research contrac-tor to the NASA Glenn Research Center. He isthe electric propulsion lead systems engineerfor the ISPT program. He also serves as amission and systems analyst for the ISPTprogram and the Glenn Research Center.John has expertise is in mission and systemsanalyses, electric propulsion systems, andtrajectory optimization. He supported pro-pulsion system development, Mars ascentvehicle design, lunar lander guidance simu-lations, planetary defense studies, and
advanced propulsion design and testing.
John has a B.S. in Physics and Aerospace Engineering and an M.S. inAerospace Engineering from Purdue University.


David Hahne managed the Multi-MissionEarth Entry Vehicle activities for the In-SpacePropulsion Technology project. A NASA-Langley employee for nearly 30 years, histechnical background is in vehicle dynamics,stability, and control. He started managingtechnology R and D efforts in the 90s for theHigh Speed Research Program and has sincebeen part of the management team of sev-eral other government-industry partnershipsdeveloping technology ranging from easy-to-fly general aviation aircraft to fuel efficient
commercial transports. He has a BS in Aero-
space Engineering from Virginia Tech and an MS in Aeronautics fromGeorge Washington University.

Michelle Munk has been a NASA employeefor nearly 20 years, first at the Johnson SpaceCenter, then at the Langley Research Center.She has been involved in Mars advancedmission studies, managed the delivery ofInternational Space Station hardware, andwas on the Mars Odyssey aerobraking opera-tions team. Since 2002, she has been theLead Engineer or Project Manager for Aero-capture Technology Development under In-Space Propulsion. Ms. Munk is also involvedin the Mars Science Laboratory Entry, Des-
cent and Landing Instrumentation (MEDLI)
project. She has a BSAE from Virginia Tech and completed graduatecoursework at the University of Houston.





Documents

Products from NASA's in-space propulsion technology program applicable to low-cost planetary missions