CubeSail (UltraSail)


CubeSail is a low-cost spacecraft propulsion demonstration mission using two identical 1.5U CubeSat satellites to deploy a 260 m (850 ft) long, 20 m2 (220 sq ft) solar sail ribbon between them.[2] This mission is a first in a series of increasingly complex demonstrations leading up to a full-scale UltraSail heliogyro[3] by the University of Illinois and CU Aerospace.

Mission typeTechnology: solar sail propulsion
OperatorNASA / University of Illinois
Spacecraft properties
Spacecraft type2 × 1.5 U CubeSats
ManufacturerUniversity of Illinois
Launch mass~ 3 kg
Start of mission
Launch date16 December 2018 (2018-12-16)[1]
Launch siteRocket Lab LC-1
ContractorRocket Lab
Orbital parameters
Reference systemGeocentric
RegimeLow Earth

Background: HeliogyroEdit

Artist's concept of a heliogyro, proposed to visit Halley's Comet in 1986. Each blade would be 8 m (26 ft) wide and 6.2 km (3.9 mi), for 0.6 km2 (0.23 sq mi) of sail area.
Solar sail types. A heliogyro could have dozens of blades

UltraSail is a proposed type of robotic spacecraft that uses radiation pressure exerted by sunlight for propulsion. It builds upon the "heliogyro" concept[4] by Richard H. MacNeal, published in 1971,[5][6][3] and consists of multiple rotating blades attached to a central hub.

The Heliogyro spacecraft's attitude (orientation), and therefore thrust direction, would be controlled by changing the cyclic and collective blade pitch similar to a helicopter.

Although the Heliogyro design has no mass advantage over a square sail, it remains attractive because the method of deploying large sail blades is simpler than a strut-based design.[7] Blade stiffness is achieved by spinning the spacecraft (centrifugal force) with its rotational axis generally pointing at the Sun.

CubeSail spacecraftEdit


The University of Illinois together with CU Aerospace designed this mission to demonstrate deployment and to measure the thrust on a 7.7 cm × 250 m membrane (about 20 m2) made of aluminized mylar. The membrane is deployed between two 1.5U CubeSats that separate from each other in low Earth orbit. It is intended as a first step towards the development of the larger solar sail concept called UltraSail.

Re-orientation of the CubeSats will cause the sail to undergo aerodynamic drag in the upper atmosphere for its disposal.


The spacecraft was selected in 2012 by NASA to be launched as part of the ELaNa program.[8][9][10]


CubeSail was launched on an Electron launch vehicle[11] on 16 December 2018 from New Zealand.[1][12]

While "satellite beacons at the correct frequency were observed post-launch once on 18 Dec. 2018", there was not "sufficient signal to noise ratio to demodulate the call sign in the beacons.", and "no further communications were received from CubeSail".[13]



The proposed second mission of the project is called I-Sail, proposed to be launched in 2022, and would consist of a 25 kg (55 lb) spacecraft with bilateral blades with a total sail area of 2,500 m2.[14] It will demonstrate thrust levels many times those of ion thrusters used for deep space missions and perform an Earth gravity escape.[14] Several science objectives are being assessed as secondary objectives.[14] The project is being funded by NASA's Small Business Innovation Research (SBIR) program.[15]


CubeSail and I-Sail are intended as steps towards the development of a larger (1,600 kg[16]) solar sail concept called UltraSail for interplanetary and interstellar missions.[17] This last consists of multiple CubeSail-like structures that extend kilometers long film blades attached to a central hub to ultimately form a heliogyro. The UltraSail blade material, the body of the solar sail, is mounted on multiple reels, each with a width of 5–10 m, and deployed to a blade length up to 5 km (3.1 mi)[16] for a total 100,000 m2 of sail area.[2][3] The spacecraft spins around the central hub to flatten the blades by centrifugal force, supported by tip-CubeSats. For the kilometre long blades' stability, this requires a rotational period of 1–2 hours so they overcome the solar pressure force by 3 to 5 times. Each blade is a thin polyimide film coated with ripstop.[16]

For UltraSail, blade control (and hence the spacecraft's attitude control) is initiated by small controllable mini-satellites (tipsat) at the tip of each blade.[16][18] The tipsat mass provides a stabilizing centrifugal force on the blade while in rotation. Each tipsat would be a 5-meter long carbon-fiber structure with a total mass of 50 kg, including avionics and 20 kg propellant (catalyzed nitrous oxide (N2O) and cold gas).[16] Alternatively, the tipsats could be propelled with electric microthrusters to control blade pitch.[19]

The maximum expected thrust force due to solar pressure is equivalent to 400 kW ion thruster systems used for comparable deep space missions.[19]

See alsoEdit

  • IKAROS, a Japanese solar sail, launched in May 2010
  • NanoSail-D2, the successor to NanoSail-D, launched in November 2010
  • LightSail, a controlled solar sail CubeSat launched in July 2019
  • Near-Earth Asteroid Scout, a solar sail CubeSat currently planned to launch in 2020
  • Sunjammer, a solar sail that was cancelled before launch in 2014


  1. ^ a b Small Satellite Design and Testing Laboratory Archived 2018-01-28 at the Wayback Machine - CubeSail. University of Illinois. 2018.
  2. ^ a b CubeSail Homesite. CU Aerospace. Accessed on 30 December 2018.
  3. ^ a b c Initial Development of the CubeSail/UltraSail Spacecraft. R. L. Burton, J. K. Laystrom-Woodard, G. F. Benavides, D. L. Carroll, V. L. Coverstone, G. R. Swenson, A. Pukniel, A. Ghosh, and A. D. Moctezuma. (2010)
  4. ^ Heliogyro
  5. ^ MacNeal R. H., "Structural Dynamics of the Heliogyro", NASA-CR-1745A, 1971.
  6. ^ Burton, R. L., Coverstone, V. L., Hargens-Rysanek, J., Ertmer, K. M., and Botter, T., "Ultrasail-Ultra-Lightweight Solar Sail Concept," 41st AIAA/ASME/SAE/ASEE Joint Propulsion Conference&Exhibit, AIAA Paper 2005-4117, 2005.
  7. ^ "Design & Construction". NASA JPL. Archived from the original on 2005-03-11.
  8. ^ Anna Heiney, ELaNa 19: CubeSail, NASA, Dec. 10, 2018. Retrieved 23 July 2019.
  9. ^ CubeSail. Gunter's Space Page, 2017. Retrieved 23 July 2019.
  10. ^ CubeSat Launch Initiative. NASA. Upcoming ELaNa CubeSat Launches. 2018.
  11. ^ STUDENT CUBESAIL SATELLITE LAUNCH IMMINENT, Grainger College of Engineering, University of Illinois, Dec. 06, 2018. Retrieved 23 July 2019.
  12. ^ Pietrobon, Steven. "New Zealand Launch Record (2009 to present)". Retrieved 14 August 2017.
  13. ^ "Welcome". Retrieved 2021-07-05.
  14. ^ a b c I-Sail: 2500-Square-Meter Solar Sail Prototype Demonstrator. NASA SBIR 2017 Solicitation. 19 April 2017.
  15. ^ ELaNa 19: CubeSail. NASA. 10 December 2019.
  16. ^ a b c d e R. L. Burton, J. K. Laystrom-Woodard, G. F. Benavides, D. L. Carroll, V. L. Coverstone, G. R. Swenson, A. Pukniel, A. Ghosh, and A. D. Moctezuma Initial development of the CubeSail UltraSail spacecraft. 27 August 2014.
  17. ^ NASA to Launch Two Small AE Satellites. Aerospace Illinois. 22 February 2012.
  18. ^ Design Concept for a Solar Sail with Individually Controllable Elements. (PDF) Tong Luo, Ming Xu, and Qingyu Qu. Journal of Spacecraft and Rockets. 2017. doi:10.2514/1.A33775
  19. ^ a b UltraSail. (PDF) R. Burton, and G. Benavides. 2003.