Jaesub Hong (Deputy–PI, Harvard), Suzanne 

Romaine (PI, SAO), Almus Kenter (SAO), Larry 

Nittler (Carnegie), Ian Crawford (Birbeck), 

David Kring (LPI), Noah Petro (GSFC) and 

NASA Ames Mission Design Center

Jan 2018

Competition Sensitive 1
Identify and measure compositions of 

lunar lower crust and upper mantle 

outcrops excavated within and around 

impact craters.

2

Nittler+2011

Schrödinger Basin

~320 km dia.

Zeenman

~180 km dia

Finsen

~72 km dia.

Picard

~22 km dia.

Example target sites guided by data from missions 

like GRAIL, LRO, Kaguya, covering diverse crater 

sizes in both the nearside and farside of the Moon

Competition Sensitive

Depth of excavated material is 

~1/10th – 1/20th of crater diameters.
3

How did the Moon form and evolve?

Science goal of CubeX is to understand 

the origin and evolution of the Moon 

through lunar elemental composition from 

X-ray fluorescence (XRF) excited by Solar 

X-rays.

• Remote-sensing XRF sensitive to most 

major rock-forming elements (e.g., Na, 

Mg, Al, Si, S, Ca, Ti, Fe)

• XRF Spectroscopy is a demonstrated 

remote-sensing geochemical 

technique in planetary science: CubeX

adds high resolution imaging to XRF 

spectroscopy

Competition Sensitive
CubeX resolves outcrop features with high angular resolution (~2 – 3 km, 

10x higher) while providing a large context with wide footprint (~110km).

4

(A) The morphology of a peak ring is evident in

this view of the ~320-km-diameter Schrödinger

basin on the Moon (NASA’s Scientific

Visualization Studio).

(B) A close-up view of a segment of the peak ring

with rocks uplifted from mid- to lower-crustal levels

by the impact event. LRO Camera image

M1192453566 [Kring+16 & 17].

Anorthositic outcrops are generally considered to be from highlands, whereas

olivine-rich outcrops are associated with the mantle or lower crust origin.

Competition Sensitive
5

• Deep space navigation is a critical issue for 

interplanetary missions.

• Current deep space navigation relies on a 

global network of large ground-based radio 

antennas such as NASA DSN and ESA 

ESTRACK.

• Performance degrades while the operational 

cost increases as the S/C travels farther away 

from Earth.

• A new era of low-cost SmallSats/CubeSats 

based space exploration will require more 

autonomous deep space navigation.

Competition Sensitive
6

• Measure the peak of the pulsation profile 

from stable millisecond pulsars (MSPs)

Shemar+16

Competition Sensitive

• Repeat the measurements for 3 or 4 

pulsars to locate the S/C position or 

determine the S/C trajectory

• MSPs are “GPS” of the Galaxy
Solar Panel

(0.4 m2)

Thruster

Terrain Camera

LGA

Star Tracker

Propulsion 

System

Battery

X-band Radio

Reaction Wheels

Solar X-ray 

Monitor (SXM)

Miniature X-ray 

Optics (MiXO)

Focal plane of CMOS & SDD

50 cm

focal 

length

X-ray Imaging Spectrometer (XIS)

7

• ~6U CubeSat X-ray Telescope: 5.8 kg with 8.6W (S/C: ~40U)

X-ray Imaging Spectrometer (XIS) and Solar X-ray Monitor (SXM)

• XIS covers 0.4 – 7 keV with <150 eV FWHM @ 1 keV, 1 sq. deg FoV with < 1 arcmin Ang. Res.: 2 –

3 km resolution with 110 km foot print at 6000 km; < 1 μsec timing resolution for XNAV

• SXM covers >130 deg FWZI with energy range of 1 – 8 keV

Competition Sensitive
Spider Fixture

(Al)

34 NiCo shells

Cross-sectional view of 34 shells

~10 cm

• Achieve <1 arcmin resolution 

over 1 sq. deg and 24 cm2 onaxis & 12 cm2 off-axis (@ 33 

arcmin) effective area at 1 keV

• 34 lightweight NiCo ENR shells 

(200 μm thick) in a butterfly 

design with 10 cm dia. x 8 cm 

length envelope (~1.5 kg) for 50 

cm focal length

Competition Sensitive 8

Effective area (left) and angular resolution in HPD (right) as a function of off-axis 

for several discrete energies (color-coded) estimated by ray-tracing simulations. 
Competition Sensitive 9

• 2 monolithic CMOS X-ray sensors: 16 μm pixel, <150 eV FWHM at 1 keV for XRF imaging 

spectroscopy

• Amptek SDD: < 1 μsec timing for XNAV 

• Enable both XRF measurements and XNAV observations without moving parts
Competition Sensitive 10

Pre-amp Board

• Initial signal conditioning for the 

output signals from the SDD

• Routing for TEC power and BIAS

• ~3.5 cm x 3.5 cm

SDD TO-8 Module

• COTS item from Amptek

• Be Optical Blocking Filter 

• SDD Cooling with 2-Stage TEC

• SDD substrate and detector

Collimator and Bracket

• Correct Angle to the Sun

• Correct FoV

• Throughput Regulation

• A simplified version of SXM in OSIRIS-REx / REXIS

• SDD: off-the-shelf item from Amptek

• REXIS SXM functions normally since launch in Sep. 2016
Solar Panel

(0.4 m2)

Thruster

Terrain Camera

LGA

Star Tracker

Propulsion 

System

Battery

X-band Radio

Reaction Wheels

X-ray Imaging 

Spectrometer

Solar X-ray 

Monitor

11

Total Vol: 35 x 23 x 68 cm

Total Mass: 43 kg

Resource Current best 

estimate

Total launch mass 43 kg

Total power draw 72 W

S/C delta-V 300 m/s

S/C data storage 

volume

8 GB

Data rate 256 kbps

Pointing control & 

knowledge

30 arcseconds &

6 arcseconds

Mission lifetime

(science operation)

1.5 yr

(1 yr)

Competition Sensitive
• CubeX is currently 

designed as a secondary 

spacecraft, deployed into 

a common lunar orbit

• Launch during solar 

maximum (2023 – 2027)

CubeX size: L x W x H (cm) 68 35 23

CubeX 

canister 

mount 

orientation 

fits all 

fairings

CubeX ESPA-mount 

orientation option

Competition Sensitive 12
13

• ~90% of 1 year science operation

• Targeted observations during day 

time 

• except for calibration sites at North 

and South poles during night time

• > 2 hr per orbit for each target site

• ~2 – 3 km resolution with ~110 km FOV

to cover and resolve key features

• 6 prime science targets and 3 

calibration sites

• Accumulate > 0.5 Msec

exposure/site at C1 solar state to 

meet science requirements 

e.g., < 30% error of abundance ratio at ~3

km scale

Sun Moon Night side Day side

Calibration 

Site

Target 1

Target 2

Target 3

Polar circular orbit at 

6000 km

Competition Sensitive
Sun

Moon

Pulsar 4

Night side Day side

Pulsar 3

Pulsar 1

Pulsar 2

14

CubeX can perform XNAV in more realistic environments for deep space navigation than 

NICER on ISS (only 20 min per orbit for each pulsar) 

CubeX science requirements & mission ops are compatible with XNAV tech demo.

Competition Sensitive

• ~10% of 1 year science

operation: 

~6 XNAV ops total with 

~6 days per ops

• Goal: achieve < 20 km 

precision

• > 2hr per orbit for each

pulsar 
Competition Sensitive 15

• CubeX will identify and measure elemental abundance of lunar mantle and lower 

crust material, which will deepen our understanding of the formation and evolution 

of the Moon, in time for next lunar sample return missions.

• CubeX will demonstrate semi-autonomous deep space navigation using X-ray 

millisecond pulsars. Autonomous navigation becomes essential in a new era of 

interplanetary exploration with a large number of SmallSats/CubeSats.

• Advances in X-ray telescopes and detectors such as Miniature lightweight X-ray 

Optics (MiXO), monolithic CMOS X-ray imaging sensors and high timing resolution 

SDDs enable these ambitious objectives with a small form factor, opening a new era 

of planetary XRF spectroscopy and deep space navigation.

• The CubeX mission design closes for science requirements, spacecraft and 

mission implementation. The design fits mass, volume and cost constraints of the 

PSDS3 call.
Competition Sensitive 16
17

Management, SOC, MOC

Suzanne Romaine (SAO) PI; MiXO Lead

Jaesub Hong (Harvard) D-PI; Instrument Design

Janet Evans (SAO) SOC

NASA ARC Msn Design, S/C Design, MOC

Lunar and XRF Science

Ian Crawford (Birkbeck) Lunar Science Lead

David Kring (LPI) Lunar Scientist

Noah Petro (GSFC) Lunar Scientist

Larry Nittler (Carnegie) Planetary XRF Scientist

XNAV

Keith Gendreau (GSFC) XNAV Lead

Jason Mitchell (GSFC) GEONS Lead

Luke Winternitz (GSFC) XNAV Plan and GEONS Sim

Instruments

Ralph Kraft (SAO) XIS Lead

Almus Kenter (SAO) CMOS Lead

Gregory Prigozhin (MIT) SDD Sensor Lead

Rebecca Masterson (MIT) Instr Mgmt, SXM Lead

Competition Sensitive