NG-20 was the twentieth flight of the Cygnus, an expendable American cargo spacecraft used for International Space Station (ISS) logistics missions that launched on 30 January 2024 and was deorbited on 13 July 2024.

The spacecraft was an Enhanced Cygnus, named the S.S. Patricia "Patty" Hilliard Robertson in honor of the NASA astronaut who died in a plane crash prior to being assigned to a crew to fly to the ISS.

As an interim solution, Northrup Grumman contracted with its CRS competitor SpaceX to launch NG-20, 21 and 22 using its Falcon 9 Block 5 rocket.

The cargo manifest is broken down as follows:[6][7] Scientific investigations traveling in the Cygnus spacecraft include tests of a 3D metal printer, semiconductor manufacturing, and thermal protection systems for re-entry to Earth's atmosphere.

In addition, this activity helps show how crew members can work safely and efficiently with printing metal parts in space.

[6] Advances in metal 3D printing technology also could benefit potential applications on Earth, including manufacturing engines for the automotive, aeronautical, and maritime industries and creating shelters after natural disasters.

[6] Manufacturing of Semiconductors and Thin-Film Integrated Coatings (MSTIC) examines how microgravity affects thin films that have a wide range of uses.

This technology could enable autonomous manufacturing to replace the many machines and processes currently used to make a wide range of semiconductors, potentially leading to the development of more efficient and higher-performing electrical devices.

Kentucky Re-entry Probe Experiment-2 (KREPE-2), part of an effort to improve thermal protection system technology, uses five capsules outfitted with different heat shield materials and a variety of sensors to obtain data on actual reentry conditions.

The capsules can be outfitted for other atmospheric re-entry experiments, supporting improvements in heat shielding for applications on Earth, such as protecting people and structures from wildfires.

[6] Longer space missions increase the likelihood that crew members may need surgical procedures, whether simple stitches or an emergency appendectomy.

To fill the gap, Northrop Grumman contracted with CRS competitor SpaceX to launch up to three Cygnus missions atop Falcon 9 Block 5 rockets.