Right-Sized Nanosatellites: Finding the
Sweet Spot between 3U/6U and ESPA
June 9, 2015
Clint Apland
(240) 228-0388
clint.apland@jhuapl.edu
Small Payload Rideshare Conference, June 2015, Applied Physics Laboratory, Laurel, MD
Topics to Discuss
 Need and Motivation
 Express-class Space Vehicle Features and Benefits
 Payload Provisions and Suitability to Payloads with Significant
Mission Utility
 Benefits of Rectangular Adaptor Systems
 First Generation Adapter System
 Second Generation Adapter System
 Future Work
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Motivation for Express Class
 An intermediary mission class standard is needed
between ESPA (181 kg) and 3/6U CubeSat (~4-12 kg), to:
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PolyPicosat
Orbital
Deployer
(P-POD)
More optimally utilize excess LV secondary payload
rideshare accommodation capability.
Enable lower cost missions when ESPA-class not needed.
Provide for more flexible and capable space vehicles than
possible w/ 3U-6U CubeSat (physical) constraints:
– E.g., larger payloads, greater power generation, propulsion

Permit more ready-use of COTS components and
technologies.
Express
Initial top-down/bottom-up study performed by APL in 2010-11
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NASA
Ames (3/6U)
NLAS Dispenser
Atlas V ESPA
Configuration
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Express Class: 25-75 kg Standardized Nanosatellite
W/O Propulsion
 Provides a standard,
flexible spacecraft
interface compatible
with multiple LVs:
W/ Propulsion

For secondary manifest:
o Space-X Falcon 1e/9/9H
o OSC Minotaur I/IV/V,
Antares,Taurus XL
o ULA Atlas V, Delta IV
o LM/ATK Athena IIc

For primary manifest:
o ORS Super-Strypi
o SMDC Nano-Launcher*
o DARPA ALASA*
 Bridges gap between
3U/6U and ESPA
* To be investigated as data
becomes available
 Optional shroud alleviates
concerns of primary Payload (PL)
damage
 Protects/conceals contents from:
Launching high performance, reliable
nanosatellites featuring inexpensive
and reliable separation systems is
possible over a wide selection of
launch vehicles
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SPRC, June 2015, JHU/APL
Visual inspection
Physical access and tampering
Aero-heating, thruster plume
thermal
Acoustics and contamination
EMI/EMC
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Express Features and Benefits
FEATURE
BENEFITS
Configurations with or
without propulsion.
> 225 m/s ΔV chemical propulsion allows rideshare
flexibility; enables formation flying and constellations.
Non-propulsion is lower cost and accommodates larger
payloads within standard volume.
Multiple PL data
interfaces.
Allows >two independent payloads.
Large payload volume.
Propulsion:
6,500 cm3 (400 in3)
Propulsion Extended: 35,000 cm3 (2100 in3)
Non-propulsion:
20,000 cm3 (1200 in3)
Size, shape and mass
less constraining than
CubeSats.
Allows more use of COTS components, can still benefit
from use of CubeSat components, appendages can
protrude if necessary.
Simplified Adaptor &
Separation System
Simple, proven, low cost, allows axial or radial
deployment, easily adapted to any LV. Flyaway half of
separation system can double as bottom deck of SV.
Available shroud.
Provides protected environment, prevents visual
inspection, tamper-resistance prevents access.
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Payload Provisions

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Nominal PL Mass: 21 kg w/o propulsion; 8 kg w/ propulsion
Data processing capability may be supported by S/C C&DH
Flexible S/C software architecture with encryption capability
Time: 1 pulse per second, GPS referenced
Solid State Recorder (Mass Memory) is scalable
Nominal PL Power:

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Orbit Average (typical orbit): >10 W
Peak: 100 W
 Available Voltages:

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Unregulated Bus: 28 V (24 to 33 V)
Regulated: 3.3 V and 5.0 V @ >4 A; Adjustable
 Attitude Determination & Control:

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Full 3-axis (zero momentum)
Control <0.1, Knowledge <0.03
 Communications: Full duplex USB/S-band (DL >1 Mbps)
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Express SERB Payloads Applicability
Criteria:
• V < 20,000
cm3 (w/o
prop.)
• P < 30 watts
• M < 15 kg
Results:
Suitable for
11 of 19 (58%)
of candidate
payloads
from 2014
SERB list,
and could
accommodate
every
CubeSat
payload
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EELV, F-9/Heavy, Antares Accommodation: ESPA
Nanosats & ESPA SVs
on a ø62” ESPA ring
(option for 3 at each
ESPA port)
B1194 PSR
Atlas V
Delta IV
5-m fairings
2x D1666 PSR
CSA Flat Plate Adaptor &
3 SVs
ESPA SV
Falcon 9
C-29 Ring
Atlas V
Delta IV
4-m fairings
Shrouded
Option
Antares
(Figure courtesy of ULA)
Clearance for
Antennas, etc.
Optional P-PODs on Moog-CSA ESPA 6U Mounts (SUMs)
(Figure courtesy of Moog-CSA)
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EELV, F-9/Heavy, Antares Accommodation: ESPA + FPA
B1194 PSR
Atlas V
Delta IV
Falcon 9
5-m fairings
Nanosats & ESPA SVs
On a CSA Flat Plate
Adaptor
ESPA SV
2x D1666 PSR
Bottom View
CubeSats (10)
Atlas V
Delta IV
4-m fairings
Antares
Moog-CSA Flat Plate
Adaptor
C-13 Adaptor (between Centaur
forward cone and CSA Flat
Plate Adaptor)
The same mixed payload topologies and ride-share flexibility is possible
with smaller LV
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Express Adapter FY15 Prototype Improvements
 Several refinements and enhancements were made
through additional detailed design, testing activities to:
Increase space vehicle mass/volume accommodation: mass-CG
curve raised
 Reduce parts count, simplify AI&T, lower costs
 Reduce adapter (baseplate) fly-away mass
 Increase customizability for specific SV equipment
accommodations
 Reduce operations required for flight mate
 Increase scalability for larger-class space vehicles
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 Next-gen design activities scheduled for 2015
Complete detailed design (Q2-3CY15)
 Prototype fabrication, separation & vibration testing (Q3CY15)
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Express Adapter Prototype Hardware
 Full adapter system prototype designed, built and vibration tested
 US Patent 8939409 for an “Adaptor System for Deploying Small Satellites”
Adapter w/ SV Baseplate
Exploring opportunities
for flight demonstration
and characterization
Z axis
Adapter Deployment H/W
Vibration Test Configuration
(without shroud)
Thermal
Test
Layout
Shroud Assembly
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Prototype Hardware Test Plan
Vibration Test Configuration
(without shroud)
 Test outline:

Sine and Random Vibration Testing in
each of 3 axes, each axis:
– Pre-test sine survey at .25g, Sine Sweep,
Random Vibration, post-test survey

Z axis
Deployments at ±60C (to be scheduled
for next-gen adaptor)
– Ambient pressure (nitrogen back-fill)
– Deployments in the direction of gravity

Deployment characterization (to be
scheduled for next-gen adaptor)
– Use 3rd party air bearing fixture
– Measure tip-off rates in axes parallel to
separation plane
– Measure separation rate
Thermal Test Layout
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Design Overview
Design is simpler, more reliable, more cost effective and
requires less volume than a ring type separation system
2x 31-pin
Separation
Connector
(picture courtesy
of HiShear
Technology
Corporation)
Low Shock
Separation
Nut
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Benefits to Small Sats of Rectangular Separation Systems
 Square interface is more efficient than circular
interface
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Small SVs are usually rectangular and don’t have the
volume for center cylinder structural elements
Most of the loads in rectangular SVs are concentrated
in the corners
Cylindrical separation systems are sensitive to load
“peaking”
To avoid load peaking, cylindrical interfaces require
large and massive structures to distribute loads
The rectangular adaptor is insensitive to load
peaking; loads are reacted from SV corners into
separation system corners
The rectangular adaptor can be easily customized to
be used as the bottom deck of the space vehicle
 Other Features & Benefits:

– Single machined deck from
flat plate
– Much lower parts count than
cylindrical adaptors
– Mechanism parts count
dramatically reduced, as
compared to cylindrical
adaptors
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– Low shock
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– Reliable with heritage
– Non-explosive actuators are
available
The rectangular adaptor is more cost effective than
cylindrical adaptors
– Separation system is less costly than cylindrical systems
– Can eliminate the cost of SV bottom deck
The rectangular adaptor is easier to set for flight than
some cylindrical separation systems
The rectangular adaptor can be used with “workhorse” LV-side GSE adaptors, unlike some cylindrical
adaptors
Separation nuts:
– Simultaneously actuated
– Increases usable SV volume and decreases total system
mass

Simple and reliable

Integral separation
connectors
– Redundant Loop-back Breakwire separation indication
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• No separation switch
“chatter”
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Future Work
 Continuing to Engage Sponsors

Performing Mission Concept Studies
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Coordinating Experimental/Prototype Flight Missions in 2016
 Seeking Industry Partners for Tech-Transfer of Express Dispenser
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APL’s role is not separation system hardware production
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Benefits our community
– Low cost, reliable, flexibly configured separation systems that reduce overall
system mass and increase usable volume
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