The Maxar Power and Propulsion Element: Third Generation … · −Generally SEP SK burn at each apolune with few RCS unloads spread around orbit −Gravity gradient torques manageable

© 2019 Maxar Technologies 1

The Maxar Power and Propulsion Element:

Third Generation Commercial Solar Electric Propulsion

Scott Tilley

Ty Lee

Maxar Space Infrastructure

Palo Alto, CA

11 December 2019

FISO Working Group

DocuSign Envelope ID: 4FC604BD-58DB-45ED-86E1-249D2D921D83


The Power Propulsion Element (PPE) is the first element in NASA’s Lunar orbiting Gateway which

will form the basis of a sustainable human return to the moon and beyond.

The PPE spacecraft is a 50kW class Solar Electric Propulsion (SEP) platform based on the 1300

bus with substantial Power, Propulsion, Communications and Avionics capabilities.

Maxar was selected as the prime contractor to design, build and launch the PPE in late 2022.

Maxar is then is responsible for demonstrating PPE’s key electric propulsion technologies and

operational capabilities in flight during a one year mission to the target cislunar orbit. After

successful demonstration, NASA has the option to acquire the PPE for use in the Gateway.

PPE Program Overview



Mission Segment Description

Gates M. et al. (2019). An Update on the Power and Propulsion Element: First Gateway Element Launch in 2022, 70th International Astronautical Congress (IAC),

Washington D.C. United States, 21-25 October 2019



PPE Demo Mission Overview

Gates M. et al. (2019). An Update on the Power and Propulsion Element: First Gateway Element Launch in 2022, 70th International Astronautical

Congress (IAC), Washington D.C. United States, 21-25 October 2019



Electric Orbit Raising (EOR) Trajectory PPE to launch on SpaceX Falcon Heavy to GTO

− Tailor perigee to lower drag early with large ROSA area

− Tailor apogee to manage time of flight in EOR, including

super-synch apogee

Working with Odyssey Space Research to define flight

trajectory and design maneuver plans

− Launch window analysis and sensitivity

− Plan separate phases of orbit transfer to NRHO with

EOR and RCS as needed

− SEP performance data acquisition

− Rideshare drop off analysis

− NRHO maintenance with SEP or RCS

Type

Perigee

Altitude

Apogee

Altitude

Inclinatio

n

Geosynchronous

Transfer Orbit

(GTO)

250-300

km

42,000 km 28.5

Ticker R. et al. (2019). The Gateway Power and Propulsion Element: Setting the

Foundation for Exploration and Commerce. the AIAA Propulsion and Energy Forum,

Indianapolis IN, 19 August 2019.



Cislunar Mission Environment - NRHO Considerations

Near Rectilinear Halo Orbit (NRHO) period of 6.6 days, ~70,000

x 3,500 km radius

− Orbit plane rotates with moon orbit of 27 days, sun phased

to minimize eclipses of max duration of 1.5 hours

Nominally flying un-crewed gateway stack end to sun to

minimize solar pressure torques

− Generally SEP SK burn at each apolune with few RCS

unloads spread around orbit

− Gravity gradient torques manageable on wheels during

perilune for lower Gateway inertia without Orion

During crew mission (~1 month per year), 3 hr Orion “tail to sun”

constraint drives RCS use

− RCS used for SK reorientations and burns at apolune

− Large gateway inertias with Orion yield large gravity

gradient torques during perilune requiring more RCS firing

To

Earth

To

Earth

Earth view

of NRHO

Expect large disturbance torque variations

over life

- Wheel control sizing

- Tankage to meet RCS/SEP use while

allowing for refueling

Large geometry variations for comm links to

Earth and Moon in sun inertial stack attitude

Tilley S. Solar Electric Propulsion (SEP) Concept for the Deep Space Gateway.

Presented at the International Space Development Configerence, Los Angeles CA, 25

May 2018.



Airlock

Module

Habitat

Module

Power

Propulsion

Element

Visiting

Orion

DSG Robotics

(ISS Derivative)

Logistics

Module

Refueling

Module

Expect large mass properties

variations over life

- C.M. shifts

- Inertia changes

- Disturbance torques

Mass Xcm Ycm Zcm Ixx Iyy Izz

Configuration (kg) (m) (m) (m) (kgm2) (kgm2) (kgm2)

1 PPE Only 8000 -3.00 0.00 0.00 110,548 129,251 27,197

2 PPE & Hab & Log & Air 38000 4.63 1.84 0.00 616,809 1,322,135 1,618,842

3 PPE & Hab & Log & Air & Orion+X 63000 10.53 1.11 0.00 731,260 4,789,453 5,137,330

PPE launched on commercial LV, then uses its SEP to move to NRHO

PPE provides attitude control, power, propulsion and communication functions to Gateway

Gateway built up over several years

PPE in Gateway

Visiting

Orion

Tilley S. Solar Electric Propulsion (SEP) Concept for the Deep Space Gateway. Presented at the

International Space Development Configerence, Los Angeles CA, 25 May 2018.



Power and Propulsion Element

Structure based on 1300-class with central cylinder housing 1000 kg

class Xenon tanks

EP with Maxar-Busek 6kW EP and NASA/Aerojet 12.5kW EP

Forward and aft refuelable for EP and RCS

Bipropellant system for impulsive maneuvers

Powered by Maxar EPS 2.0 system with Li-Ion batteries

Two ROSA wings with central hinge and dual rollout blankets

Control system hardware with Star Tracker, Reaction Wheels, Fiber

Optic Gyro, Sun Sensor, Attitude Control Electronics (ACE), RCS

thrusters, EP gimbals

C&DH subsystem with heritage Maxar ICU for bus functions, and new

mission processors for the Gateway interface

X & Ka-band Steerable High Gain Antennas (SHGA) and X-band omni

for Earth comms, Ka-band SHGA for Lunar comms, S-band for RPO

Lee, T. Commercial Solar Electric Propulsion at Maxar. Presented at the AIAA Propulsion and Energy

Forum, Indianapolis IN, 19 August 2019.



1st Gen SEP Initial Capabilities for Orbit Maintenance

100V 10kW 1.5kW 300V 0.08N 1,500s Isp

Solar Array Power Processing Electronics Hall Effect Thrusters

Maxar heritage 10kW class rigid panel arrays

Lightweight efficient Power Processing

Then state of the art Hall effect-thruster

− SPT-100

− First Maxar flight in 2004

Mission: 3kW SEP North South Station Keeping (NSSK), Limited Electric Orbit Raising (EOR)

Maxar Maxar

170 Kg Xe

Fakel

Lee, T. Commercial Solar Electric Propulsion at Maxar. Presented at the AIAA Propulsion and Energy Forum, Indianapolis IN, 19 August 2019.



2nd Gen SEP Enables Major Electric Orbit Raising (EOR)

100V 13kW 4.5kW 300V 0.25N 1,800s Isp


Maxar and DSS qualification program for Roll Out Solar Array (ROSA) wing at 13kW each

Modular PPU architecture

Increased Thrust, Isp, Throughput, and Throttle Range

− SPT-140

Mission: 13kW SEP, Full EOR, Fully Electric Spacecraft, Increased throttle range for deep space

missions

High-Power

High Voltage

Planar Magnetics

MaxarMaxar/DSS

500 kg Xe

Fakel




3rd Gen SEP Enables Major Space Transport & Exploration

100V 30kW 6 - 12kW 300 - 600V 0.3 - 0.6N 2,600s Isp

Stacked

300V

Outputs

Magnetically

Shielded

MaxarMaxar/DSS

~1,500 kg Xe

NASA/Aerojet


Busek

Currently developing a 30kW class wing for the Power and Propulsion Element leveraging elements

from Maxar GEO ROSA

Evolution of Modular PPU architecture to multimode 6kW-300/600V and beyond

Increased Thrust, Specific Impulse, Throughput, and Throttle Range

− 6kW Busek Thruster

− 12.5kW Aerojet EP string

Mission: 50kW SEP, cislunar space transport, deep space missions




PPE SEP System Diagram

ROSA

SADA

External

Interface

Loads

Bus

Loads

ROSA

SADA

Battery

Battery

Battery

Battery

NASA

Docking

System

Power

Conditioning

Unit A

Power

Conditioning

Unit B

12

kW H

ET

(2)

6kW

HE

T (2

)

Xe COPV (2)

XFCAEP

S P

PU

6kW

P

PU

(2

)

Pressure Regulation

Routing & Isolation

Latch Valves

Refueling Port

XFC

XFC

Gimbal

Gimbal

To

Gate

way

Gates M. et al. (2019). An Update on the Power and Propulsion Element: First Gateway Element Launch in 2022, 70th International Astronautical Congress (IAC),

Washington D.C. United States, 21-25 October 2019



Kickoff (June 2019)

Completed System Requirements Review

(September 2019)

Completed Phase 0 Safety Review

(November 2019)

Currently in Preliminary Design Phase

− Long lead hardware on order

− Preliminary Design Review (February

2020)

− Phase 1 Safety Review (April 2020)

− Baseline Concept Review (May 2020)

PPE Current Status


2019-12-06T13:52:10-0800Digitally verifiable PDF exported from www.docusign.com

Documents

The Maxar Power and Propulsion Element: Third Generation … · −Generally SEP SK burn at each apolune with few RCS unloads spread around orbit −Gravity gradient torques manageable