Minimize ISS Utilization: Cygnus CRS OA-7

ISS Utilization: Cygnus CRS OA-7 mission of Orbital ATK

Science payloads     Launch    Secondary payloads (CubeSats)     References

Cygnus is a low-risk design incorporating elements drawn from Orbital ATK and its partners' existing, flight-proven spacecraft technologies. The Cygnus spacecraft consists of two modules: the Service Module (SM) which incorporates the avionics, propulsion and power systems from Orbital ATK's flight proven LEOStar and GEOStar spacecraft buses; and the Pressurized Cargo Module (PCM) which carries the crew supplies, spares and scientific experiments. The SM is integrated and tested at Orbital ATK's Dulles, Virginia satellite manufacturing facility. The PCM is supplied by Thales Alenia Space and is produced in Turin Italy. 1)

For the OA-7 mission, Orbital ATK is using the Enhanced Cygnus PCM (Pressurized Cargo Module) to deliver cargo to the International Space Station. The cargo capability of the Enhanced Cygnus, developed by Thales Alenia Space, is more than 3500 kg with a total volumetric capacity of 27 m2.

PCM (Pressurized Cargo Module)

SM (Service Module)


5.1 m


GEOStar, LEOStar


3.05 m

Height, Max. diameter

1.29 m, 3.23 m


Multi-Purpose Logistics Module

Power generation

2 fixed wing "UltraFlex™" solar arrays, ZTJ Gallium Arsenide cells

Total cargo mass capacity

3,513 kg

Power output

3.5 kW (sun-pointed)

Pressurized volume

27 m3


32 x 7 lbf REA, 1 x 100 lbf DVE

Berthing at ISS

CBM Node-1 nadir or Node-2 nadir


Dual-mode N2H4/MON-3 or N2H4

Table 1: Cygnus CRS OA-7 spacecraft parameters


Figure 1: Photo of the Orbital ATK Cygnus spacecraft inside the Payload Hazardous Servicing Facility at NASA's Kennedy Space Center in Florida (image credit: NASA)



Science payloads:

• A new, nearly self-sufficient plant growth system by NASA is headed to the ISS. The APH (Advanced Plant Habitat) will be used to conduct plant bioscience research on the space station, and help NASA prepare crew to grow their own food in space during deep-space exploration missions. The new plant system will join Veggie - NASA's first fresh food growth system already active on station. 2) 3)

- APH (Advanced Plant Habitat): APH is designed to to enable investigators to better understand the mechanics of plant growth in space, the fully-enclosed habitat will join the ongoing Veggie experiment, which is presently growing fresh food aboard the ISS. Already, small flowering plants related to cabbage and mustard have been grown on Earth in a prototype habitat and will also be grown on-orbit by the Expedition 50 and 51 crews. The habitat carries more than 180 sensors to measure temperature, oxygen content and moisture levels and, unlike the Veggie hardware, requires relatively little crew time to install, add water and maintain. The APH will be installed into a standard EXPRESS (EXpedite the PRocessing of Experiments to Space Station) rack inside Japan's Kibo laboratory module. The APH assembly has a size of 53 x 91 x 61 cm and requires 735 W of electrical power during normal operations.


Figure 2: Illustration of the APH (Advanced Plant Habitat) assembly (image credit: NASA)

• ADC (Azonafide Antibody-Drug Conjugates) in microgravity. The investigation tests new antibody drug conjugates, developed by Oncolinx. ADCs in microgravity could provide better drug designs for cancer patients.

• SUBSA (Solidification Using a Baffle in Sealed Ampoules): The SUBSA furnace and inserts provide for improved crystal growth in microgravity. The SUBSA investigation was originally operated successfully aboard the space station in 2002. Although it has been updated with modernized software, data acquisition, high definition video and communication interfaces, its objective remains the same: advance our understanding of the processes involved in semiconductor crystal growth.

• ZBOT (Zero Boil-Off Tank): ZBOT is a NASA/GRC (Glenn Research Center) experiment with the objective to study ways to relieve fluid pressure on board without the loss of fluid. — Spacecraft rely on liquids for everything from fuel to life support systems for astronauts. Storing these liquids at the correct temperature and pressure is essential to prevent loss of fluids or failure of a storage tank. Human life in space is a balancing act of reliable systems and meticulous planning. 4) 5)

- Rocket fuel and other liquids used in space are stored at cryogenic temperatures of -252ºC to -152ºC. As these liquid cryogens are warmed by the environment, they evaporate, which increases pressures inside storage tanks.

- In the presence of gravity, like on Earth, liquid moves heat around by a process known as natural convection. However, the lack of gravity makes the problem more complex. "In microgravity there is almost no natural convection," said ZBOT project manager William Sheredy. "Warm liquid doesn't distribute its heat as well. As a result, cryogenic tanks experience building pressure, a situation we have to manage."

- ZBOT's small-scale, microgravity tests on the space station will use a volatile fluid that boils at 30ºC, to simulate a cryogen, and study ways to mitigate pressure in storage tanks. Results from the investigation will help improve tank design for long-term cryogenic liquid storage and pressure control.

- ZBOT will explore techniques where there is no boil-off. In doing so, data gathered from the experiment will verify and validate models for fluid tank pressurization. These models can be used to design future, larger storage tanks of cryogenic fluids. This research ultimately reduces the risk and costs of future space expeditions.

- On-orbit, the space station crew will install ZBOT hardware and set up the tests. After that, the experimental runs are remotely controlled from Earth by NASA Glenn's ISS Payload Operations Center in Cleveland, Ohio. Test results are downlinked for analysis and planning of future tests.


Figure 3: ZBOT in the Microgravity Science Glovebox Engineering Unit Work Volume at NASA/MSFC (Marshall Space Flight Center) in Huntsville, Alabama (image credit: NASA)

• The OA-7 mission Cygnus carries the Saffire-3 space combustion experiment from NASA/GRC (Glenn Research Center ) to study flame development in the microgravity environment. The experiment will be conducted after Cygnus departs the International Space Station. The results will be downloaded via telemetry prior to reentry. Cygnus will also carry the Reentry Data Collection (RED-Data-2) flight recorder to provide crucial data about the extreme conditions a spacecraft encounters during atmospheric reentry.

- After Cygnus undergoes thermal breakup, the RED-Data-2 capsule will enter the high-temperature flows to test a pair of new formulations of conformal TPS (Thermal Protection System ) material under development by NASA/ARC ( Ames Research Center) in Moffett Field, Calif. Specifically, these materials are the lightweight C-PICA (Conformal Phenolic Impregnated Carbon Ablator) and C-SIRCA (Conformal Silicone Impregnated Refractory Ceramic Ablator), with a new variant of the Avcoat ablator destined for use on NASA's Orion spacecraft also under test. 6) 7)

- December 2016: TVA (Terminal Velocity Aerospace) LLC of Atlanta, GA completed development and testing of low cost reentry data recorders and hypersonic flight test platforms and delivered three RED-Data-2 flight units to NASA/JSC for integration into an Orbital ATK Cygnus cargo resupply vessel (Figure 4) to be launched to the ISS aboard the Orbital ATK Cygnus-OA-7 flight. 8)

- TVA's RED-Data2 units are designed to record break-up data from reentering spacecraft. This information will help scientists and engineers understand the demise of spacecraft in Earth's upper atmosphere due to structural and aerothermodynamic loads. The first three RED-Data2 flight units are also evaluating the performance of different heat shield materials that may be used on future US space missions. The units are carrying additional instrumentation and embedded thermocouples to record heat shield performance during entry.

- After transmitting the recorded data, the three small capsules will be disposed into the Pacific Ocean at the end of their mission. Each RED-Data2 unit is approximately 23 cm at its maximum diameter and has a mass of approximately 2.4 kg. They are packed in protective aluminum housings for the trip to ISS. During their re-entry mission, the aluminum housings will separate and allow the RED-Data2 capsules inside to experience several minutes of free flight. Terminal Velocity is conducting this flight test under an SBIR contract from NASA Johnson Space Center. The project is also supported by a Space Act Agreement from NASA/ARC ( Ames Research Center). The Aerospace Corporation has also provided technical assistance.


Figure 4: Photo of a RED-Data 2 flight unit (image credit: TVA)

In addition to the science payloads, Cygnus will transport a multitude of other hardware, totaling 3,202 kg to the ISS on the OA-7 mission. This includes 1,215 kg of vehicle hardware,954 kg of crew supplies, 940 kg of utilization payloads, 2 kg of computer resources and 18 kg of equipment for the station's ROS (Russian Orbital Segment). Additionally, about 73 kg of EVA (Extravehicular Activity) equipment—specifically, EMU (Extravehicular Mobility Unit) leg assemblies, boots, arm-sleeves, a toolkit, tether extensions and support tools—will be aboard.


Launch: The Cygnus CRS (commercial Resupply Services) OA-7 capsule was launched on April 18, 2017 (15:11 UTC) by ULA (United Launch Alliance) on an Atlas-5 401 vehicle from the Air Force Station SLC-41, at Cape Canaveral,FL. — Prior to launch, the CRS OA-7 mission was given the name S.S. John Glenn, in honor of astronaut and senator of Ohio, John Glenn, the first US astronaut to orbit the Earth on Mercury 6 and the oldest to go to space on STS-95. John Glenn passed away in December 2016 at age 95. 9) 10)

Orbit: Near-circular orbit, altitude of ~ 400 km, inclination of 51.6º (β angle variation: 0-75º).

This mission marks the third time ULA's Atlas -5 has launched spacecraft on its way to the ISS.

OA-7 cargo: The total mass is ~7,225 kg, including 3,376 kg of internal pressurized cargo:

• Total pressurized cargo: 3,376 kg

- Science Investigations: 940 kg

- Crew Supplies: 954 kg

- Vehicle Hardware: 1,215 kg

- Spacewalk Equipment: 73 kg

- Computer Resources: 2 kg

- Russian Hardware: 18 kg

• Unpressurized cargo: 83 kg (CubeSats).


Figure 5: Illustration of the deployed Cygnus OA-7 spacecraft (image credit: Orbital ATK)



Secondary payloads (CubeSats):

Cygnus will deploy four of the CubeSats following its departure from the space station. The remaining CubeSats will remain aboard the ISS for deployment at a later date. CubeSat deployments from the International Space Station are made via the airlock of the Japanese Kibo module. 11)

• Altair-1, a 6U CubeSat technology demonstration mission of Millennium Space Systems, El Segundo, CA, USA. The NanoRacks-ALTAIR™ pathfinder investigation tests and space qualifies new platform technologies.

• IceCube (Ice particle measurements within Clouds), a NASA/GSFC 3U CubeSat technology demonstration mission.

• HARP (Hyper Angular Rainbow Polarimeter), a 3U CubeSat of UMBC (University of Maryland, Baltimore County)

• CSUNSat-1, a 2U CSUN (CubeSat of California State University Northridge).

• CXBN-2 (Cosmic X-Ray Background-2), a 2U CubeSat of Morehead State University, Morehead, Kentucky.

• OPEN (Open Prototype for Educational NanoSats), a 1U CubeSat of UND (University of North Dakota).

• Violet, a 1U CubeSat of Cornell University, Ithaca, N.Y.

• Biarri-Point, a 3U CubeSat technology mission, a four nation defence related project involving Australia, the US (NRO), the UK and Canada. Biaari is an RF signal collection mission that can be related to the spot beam mapping mission through mutual use of GPS signals. The goal is to test formation flying satellites for military use. 12) 13)

In addition, four Lemur-2 satellites, operated by Spire Global Inc. of San Francisco, were launched aboard the Cygnus OA-7 cargo craft to replenish and expand the company's constellation dedicated to obtaining global atmospheric measurements for operational meteorology and tracking ship traffic across the planet for various commercial applications. The four Lemur-2 CubeSats are mounted externally to the cargo ship. After Cygnus departs the station in July, it will climb to a higher altitude, around 500 km, and eject them into space.

QB50 x 28. Twentyeight CubeSats of the international QB50 constellation, a European FP7 (7th Framework Program) Project for Facilitating Access to Space and managed by the Von Karman Institute for Fluid Dynamics in Brussels, Belgium, were flown to the ISS for subsequent deployment (atmospheric research). The 28 CubeSats (all 2U except one with a 3U form factor) of the QB50 constellation were integrated into 11 NanoRacks 6U deployers. 14) 15) 16)
Note: The satellites will eventually be deployed into LEO over a period of 30 to 60 days as the ISS orbits the Earth.

- Aalto-2 of Aalto University, Aalto, Finland is hosting the m-NLP (Multi-Needle Langmuir Probe) payload.

- Aoxiang-1 of NPU (Northwestern Polytechnical University), China/Belgium, carries a FIPEX (Flux-Phi Probe Experiment) payload.

- Atlantis of the University of Michigan,USA carries a FIPEX payload.

- BeEagleSat of Istanbul Technical University and Halvesan (a defence contractor in Turkey owned by the government) carries a m-NLP payload.

- Challenger of the University of Colorado, Boulder, CO, carries an INMS payload.

- Columbia, built by the Universidad del Turabo, Gurabo, Puerto Rico/USA, carries a FIPEX payload.

- ExAlta-1 (Experimental Albertan-1), a 3U CubeSat of the University of Alberta, Canada, is equipped with m-NLP.

- DUTHSat was built by the University of Thrace, Greece. It features the M-NLP payload.

- HAVELSAT of Istanbul Technical University and Halvesan (a defence contractor in Turkey owned by the government); it carries the m-NLP payload.

- Hoopoe-2, of the Herzliya Science Center, Israel, is equipped with the m-NLP payload. The CubeSat, named for Israel's national bird, the Duchifat-2 (in English, Hoopoe-2), was built by Israeli high school students. More than 80 Israeli teenagers from around the country—in grades 9-12—came to Herzliya Science Center to help build the tiny 1.8 kg 2U CubeSat, a type of miniaturized satellite for space research. 17)

- INSPIRE-2 of the University of Sydney, Australia, features the m-NLP payload.

- LilacSat-1 of HIT (Harbin Institute of Technology), China/Belgium, carries the INMS (Ion-Neutral Mass Spectrometer) payload.

- LINK (Little Intelligent Nanosatellite of KAIST), Korea, is equipped with an INMS payload.

- NJUST-1 of Nanjing University of Science and Technology, China/Belgium, is equipped with an INMS payload.

- nSIGHT-1, developed by SCS-Space of Cape Town, South Africa. The CubeSat carries the FIPEX payload.

- PHOENIX of the National Cheng Kung University, Taiwan, carries an INMS payload.

- PolyITAN-2-SAU of the National Technical University, Ukraine, carries a FIPEX payload.

- qbee50-LTU-OC of the Lula University of Technology, Sweden, and partner Open Cosmos Ltd of England carries a FIPEX payload.

- QBITO of the Universidad Politécnica de Madrid, Spain, carries an INMS payload.

- SNUSat-1 and SNUSat-1B of the Seoul National University, Korea, both satellites carry the FIPEX payloads.

- SOMP-2 (Student's Oxygen Measurement Project 2) of the Technical University of Dresden, Germany, features the FIPEX payload.

- SpaceCube was built by Ecole des Mines Paristech of France; it carries the m-NLP payload.

- SUSat of the University of Adelaide, Australia, the CubeSat features an INMS payload.

- UNSW-ECO of the University of New South Wales, Australia. It is equipped with the INMS payload. - In addition, the UNSW-ECO features a total of four experiments including a GPS receiver, and two boards testing radiation-robust software and self-healing electronics. The fourth experiment is to test the satellite's chassis, built using a 3D-printed material never before flown in space. 18)

- UPSat was built by the University of Patras (Greece) and the Libre Space Foundation. UPSat is the first CubeSat to be based on open-sources software. DUTHSat it featues the m-NLP (Multi-Needle Langmuir Probe) payload.

- X-CuveSat was built by the Ecole Polytechnique, the CubeSat carries the FIPEX payload.

- ZA-AeroSat, developed by Stellenbosch University, Stellenbosch, South Africa. It carries the FIPEX payload.

The NanoRacks-QB50 project uses the ISS to deploy a constellation of 28 CubeSats, from a total of 36, in order to study the upper reaches of the Earth's atmosphere over a period of 1 to 2 years. This constellation is the result of an international collaboration involving academia and research institutes from 23 different countries around the world. The project, coordinated by the QB50 Consortium, receives funding from the European Union's Seventh Framework Program for Research and Technological Development. The QB50 satellites conduct coordinated measurements on a poorly studied and previously inaccessible zone of the atmosphere referred to as the thermosphere. The project monitors different gaseous molecules and electrical properties of the thermosphere to better understand space weather and its long-term trends. 19)

The majority of QB50 satellites carry one of three standard instrument packages, consisting of a primary instrument and an array of thermistors, thermocouples and resistant temperature detectors. The primary instruments are either: INMS (Ion-Neutral Mass Spectrometer), FIPEX (Flux-Phi Probe Experiment) or m-NLP (Multi-Needle Langmuir Probe). These experiments are geared towards collecting long-term continuous in-situ measurements of conditions in Earth's lower thermosphere. Instead of the scientific equipment, a small number of QB50 satellites will carry technology demonstration payloads.

The QB50 satellites aboard the Cygnus OA-7 flight come from a total of seventeen different countries: Australia, Belgium, Canada, Finland, France, Germany, Greece, Israel, the People's Republic of China, the Republic of China, South Africa, South Korea, Spain, Sweden, Turkey, Ukraine and the United States.


Research overview:

• NanoRacks-QB50 has the following four objectives that include facilitating access to space, carrying out a scientific measurement campaign with a satellite constellation to probe the middle and lower thermosphere, demonstrating new technologies in orbit, and promoting space engineering and science education.

• The mid-lower thermosphere (400 km to 200 km altitude) is largely unexplored and only few measurements exist below 300 km altitude. The QB50 project constellation is the first ever mission to target such altitudes with a large number of atmosphere sensors.

• QB50 offers the opportunity to have multi-point measurements of the thermosphere with a unique space and time resolution.

• A synchronized data acquisition among the sensors of the constellation allows the observation of fast travelling and small scale waves in the thermosphere.

• The scientific database is used to validate and enhance global atmosphere models and improve the understanding of physical processes which are taking part in the ionosphere-thermosphere coupling.


Cygnus capture:

The Cygnus OA-7 vehicle John Glenn arrived at the station on April 22 at 11:02 GMT for capture and berthing. Expedition 51 astronauts Thomas Pesquet of ESA and Peggy Whitson of NASA used the space station's robotic arm to grapple Cygnus. Ground controllers working via remote command then took over and used the arm to maneuver Cygnus to the underside of the Unity module and seat the cargo ship into the berthing port. Sixteen electrically-driven bolts were engaged to structurally mate the craft to the station, a mark officially achieved at 12:39 GMT. 20)

Cygnus arrived at the station with approximately 3,450 kg of cargo, including a NanoRacks cubesat deployer, food, clothing, crew supplies, spare parts, packaging materials, and laboratory equipment. The cargo delivery also included four powered, mid-deck lockers. Resembling freezers, these lockers received power after they were loaded onto the cargo module. Each locker carries critical science samples and experiments for the crew. 21)


Figure 6: Canadarm2 is used to position the Cygnus CRS-7 vehicle for berthing to the Unity module on April 22, 2017 (image credit: NASA TV)


Figure 7: Four spacecraft are parked at the station including the Orbital ATK Cygnus OA-7 resupply ship, the Progress 66 cargo craft, and the Soyuz MS-03 and MS-04 crew vehicles (image credit: NASA) 22)

The Cygnus spacecraft will spend approximately four months attached to the space station. Cygnus will remain until June 21, 2017, when the spacecraft will depart with about 1500 kg of disposable cargo. On June 28, it will return through a controlled destructive reentry into Earth's atmosphere over the Pacific Ocean.


1) "Cygnus™ OA-7 Mission," Orbital ATK Fact Sheet, URL:

2) Linda Herridge, "New Plant Habitat Will Increase Harvest on International Space Station," NASA, March 2, 2017, URL:

3) Ben Evans, "NASA Outlines Science Payloads, Ahead of Next ISS-Bound Cygnus Cargo Mission," URL:

4) "Zero Boil-Off Tank Experiment (ZBOT)," NASA, URL:

5) "Investigation on Space Station to test minimizing pressure of space travel," Space Daily, April 20, 2017, URL:

6) Adam T. Sidor, "Design and Development of RED-Data2: A Data Recording Reentry Vehicle," Georgia Institute of Technology, Aug. 1, 2014, URL:

7) "Thermal Protection Material Flight Test and Reentry Data Collection (RED-Data2)," NASA, March 8, 2017, URL:

8) "RED-Data 2 Flight Units Delivered to NASA JSC," TVA, Dec. 22, 2016, URL:

9) "NASA Space Station Cargo Launches aboard Orbital ATK Resupply Mission," NASA, Release 17-029, April 18, 2017, URL:

10) "Mission Page: OA-7 Space Station Cargo Resupply," Orbital ATK, April 18, 2017, URL:

11) "United States Commercial ELV Launch Manifest," Dec. 28, 2016, URL:

12) Eamonn P. Glennon, Joseph P. Gauthier, Mazher Choudhury, Kevin Parkinson, Andrew G. Dempster, "Project Biarri and the Namuru V3.2 Spaceborne GPS Receiver," IGNSS (International Global Navigation Satellite Systems Society) Symposium 2013, Outrigger Gold Coast, Australia, 16 – 18 July 2013, URL:

13) Jacob A. LaSarge, "A CubeSat mission for mapping spot beams of geostationary communication satellites," Thesis, March 2015, URL:

14) Davide Masutti, "QB50-ISS CubeSats ready to be launched," Dec. 9, 2016, URL:

15) US Commercial ELV Launch Manifest, March 5, 2017, URL:

16) "CubeSats Participating in the QB50 Project," List of participants in the QB50 project, 9 March 2017, URL:

17) "A Big Dream for Israeli High School Students' SmallSat is Successful," Satnwes Daily, April 24, 2017, URL:

18) Andrew Dempster, "Australia's back in the satellite business with a new launch," Space Daily, April 20, 2017, URL:

19) "NanoRacks-QB50," NASA, March 15, 2017, URL:

20) Justin Ray, "Cygnus freighter arrives at space station with bounty of supplies and new science," Spaceflight Now, April 22, 2017, URL:

21) "Rendezvous and Berthing at ISS Has Been Successfully Completed by Orbital ATK's Cygnus," SatNews Daily, April 24, 2017, URL:

22) Mark Garcia, "Cygnus Bolted to Station for Three Month Stay," NASA, April 22, 2017, URL:

The information compiled and edited in this article was provided by Herbert J. Kramer from his documentation of: "Observation of the Earth and Its Environment: Survey of Missions and Sensors" (Springer Verlag) as well as many other sources after the publication of the 4th edition in 2002. - Comments and corrections to this article are always welcome for further updates (

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