RSat-P (Repair Satellite-Prototype)
Diagram of RSat-P manipulating an object with its two robotic arms.
NamesRepair Satellite-Prototype
Mission typeTechnology demonstration
OperatorUnited States Naval Academy (USNA)
COSPAR ID2018-104F Edit this at Wikidata
SATCAT no.43854
Mission duration1995 days, 16 hours, 26 minutes
(in progress)
Spacecraft properties
Spacecraft typeCubeSat
Bus3U CubeSat
ManufacturerUnited States Naval Academy (USNA)
Launch mass≈ 5 kg (11 lb)
Dimensions10 × 10 × 30 cm (3U)
Start of mission
Launch date16 December 2018, 06:33:00 UTC[1]
Launch siteMahia LC-1A
ContractorRocket Lab
Orbital parameters
Reference systemGeocentric orbit
RegimeLow Earth orbit

RSat-P (Repair Satellite-Prototype) is a microsatellite built by the United States Naval Academy (USNA) in Annapolis, Maryland. The small spacecraft is a 3U CubeSat intended to demonstrate capabilities for minor in-orbit repair of a much larger, conventional spacecraft.

RSat-P was launched on 16 December 2018 on an Electron rocket as part of NASA's Educational Launch of Nanosatellites (ELaNa) Mission 19.[1]


It has been determined that about 1/3 of all commercial spacecraft failures originate on their solar panel deployment, wiring, sunshield, or antenna deployment,[2] so RSat-P is set to test the potential of a CubeSat to fix such small-scale large-impact failures.[2] Potential deployments include an RSat embedded in its host spacecraft, where it uses its claws to crawl along the failed spacecraft to diagnose and repair. Alternatively, an RSat could be released from a nearby constellation spacecraft in combination with a propulsive BRICSat unit to reach the failed spacecraft.[2]

While the RSat may be limited to diagnostics and minor repairs, more complex servicing would be performed by a large spacecraft called Robotic Servicing of Geosynchronous Satellites (RSGS), that is being developed by the Defense Advanced Research Projects Agency (DARPA).[2]

The team includes Edward Hanlon, Benjamin Keegan and Morgan Lange, Jacob Pittman, Gavin Roser and Dakota Wenberg; the adviser is Jin Kang.[3] In 2017, the team was awarded the Secretary of the Navy's Innovation Scholar Award, at a ceremony at The Pentagon, for their research project.[3] The first robotic arm prototype was scheduled for a launch in early 2017, but was postponed for December 2018.[4]


RSat-P is a small 3U CubeSat that is part of the Autonomous On-orbit Diagnostic System (AMODS) being developed by the U.S. Naval Academy satellite laboratory to demonstrate diagnostic and repair capabilities by validating some key robotic functions while in orbit.[3][5][4][6] AMODS consists of two main components: RSat and BRICSat, which acts as the propulsive unit for RSat, but for the prototype RSat-P mission, the satellite will not have propulsion.[2] The two robotic arms will be moved through some test patterns to simulate the repair of a damaged spacecraft.[1]

The combined mission of an RSat with BRICSat is called "The Modified BRICSat-RSat Space Experiment" (MBSE), which will be launched some time after the validation of the robotic arms on RSat-P.[2] The electric thrusters on BRICSat are called "Micro-Cathode Arc Thruster" (μCAT), developed by the George Washington University.[2][7]

Robotic arms

RSat-P represents the first time robotic arms have been installed on such a small platform.[3] The robotic arms are made of 3D printed carbon fiber, they have 7 degrees-of-freedom each, are 60 cm (24 in) long, and have a total arm-span of 1.5 m (4 ft 11 in). RSat-P has a CMOS camera attached at the center of the body to monitor the accuracy of the arm movements, and there are two more cameras fitted to the claws, enabling the satellite to provide on-demand diagnostic pictures of itself.[8]


As of 2016 The main tasks to demonstrate in this mission include:[2][9]

See also

Result of in-orbit tests

It was planned that "two robotic arms that will be moved through one or more test patterns to simulate the repair of a damaged spacecraft."[1]

This section needs expansion. You can help by adding to it. (November 2021)


  1. ^ a b c d Rocket Lab Electron launches ELaNa-XIX mission Thomas Burghardt, 15 December 2018
  2. ^ a b c d e f g h RSat Flight Qualification and Test Results for Manipulable Robotic Appendages Installed on 3U CubeSat Platform, D.L. Wenberg, B.P. Keegan, M.E. Lange, Edward A.S. Hanlon, et al. United States Naval Academy 30th Annual AIAA//USU Conference on Small Satellites 2015
  3. ^ a b c d AMODS - Mission United States Naval Academy (USNA) Accessed on 16 December 2018 Public Domain This article incorporates text from this source, which is in the public domain.
  4. ^ a b State of the Art of Small Spacecraft Technology: Structures, Materials and Mechanisms Bruce Yost, NASA Accessed on 16 December 2018 Public Domain This article incorporates text from this source, which is in the public domain.
  5. ^ RSat-P (Repair Satellite-Prototype), Gunter Krebs, Gunter's Space Page, Accessed on 16 December 2018
  6. ^ Leveraging the Autonomous Mobile On-orbit Diagnostic System to Initiate a Doctrinal Shift in Spacecraft Operations Archived 16 December 2018 at the Wayback Machine E.A. Hanlon, B.P. Keegan, M.E. Lange, J.K. Pittman, D.L. Wenberg, J.G. Roser, J.S. Kang; United States Naval Academy, June 2017 Public Domain This article incorporates text from this source, which is in the public domain.
  7. ^ μCAT Micro-Propulsion Solution for Autonomous Mobile on Orbit Diagnostic System Jonathan Kolbeck, Joseph Lucas, et al.; 30th Annual AIAA//USU Conference on Small Satellites, 2015
  8. ^ RSat-P Jin Kang, Research and Projects United States Naval Academy (USNA) Accessed on 16 December 2018 Public Domain This article incorporates text from this source, which is in the public domain.
  9. ^ Design Features and Flight Results for the Autonomous Mobile On-orbit Diagnostic System (AMODS) Edward A. Hanlon AIAA SPACE 2016 doi:10.2514/6.2016-5618