 S.S.Francis R. "Dick" Scobee (NG-21) spacecraft approaches the ISS | |
| Names | CRS NG-21 |
|---|---|
| Mission type | ISS resupply |
| Operator | Northrop Grumman |
| COSPAR ID | 2024-139A |
| SATCATno. | 60378 |
| Mission duration | 237 days, 19 hours and 12 minutes |
| Spacecraft properties | |
| Spacecraft | S.S.Francis R. "Dick" Scobee |
| Spacecraft type | Enhanced Cygnus |
| Manufacturer |
|
| Start of mission | |
| Launch date | 4 August 2024, 15:02:53 (2024-08-04UTC15:02:53Z) UTC (11:02:53 am EDT) |
| Rocket | Falcon 9 Block 5B1080-10 |
| Launch site | Cape Canaveral,SLC‑40 |
| Contractor | SpaceX |
| End of mission | |
| Disposal | Deorbited |
| Decay date | 30 March 2025, 10:15 UTC |
| Orbital parameters | |
| Reference system | Geocentric orbit |
| Regime | Low Earth orbit |
| Inclination | 51.66° |
| Berthing atISS | |
| Berthing port | Unitynadir |
| RMS capture | 6 August 2024, 07:11 UTC |
| Berthing date | 6 August 2024, 09:33 UTC |
| Unberthing date | 28 March 2025, 08:50 UTC |
| RMS release | 28 March 2025, 10:57 UTC |
| Time berthed | 233 days, 23 hours and 17 minutes |
| Cargo | |
| Mass | 3,857 kg (8,503 lb) |
| Pressurised | 3,843 kg (8,472 lb) |
| Unpressurised | 14 kg (31 lb) |
 Mission patch | |
NG-21 was the twenty-first flight of theCygnus, anexpendable Americancargo spacecraft used forInternational Space Station (ISS)logistics missions, that launched on 4 August 2024 and was deorbited on 30 March 2025. It was operated byNorthrop Grumman under aCommercial Resupply Services contract withNASA. The spacecraft was an Enhanced Cygnus, named theS.S.Francis R. "Dick" Scobee in honor of the NASA astronaut who died in theSpace ShuttleChallenger disaster.
NG-21 was the second launch of aCygnus spacecraft after Northrop Grumman exhausted the supply of itsAntares 230+ rocket. The Antares used a Russian-built engine and Ukrainian-built first stage, and production ceased after theRussian invasion of Ukraine. Northrop Grumman expects its next-generationAntares 300 rocket that does not depend on Ukrainian or Russian parts to be ready to fly NG-23. As an interim solution, Northrop Grumman contracted with its CRS competitorSpaceX to launch NG-20, 21 and 22 using itsFalcon 9 Block 5 rocket.
Cygnus was developed byOrbital Sciences Corporation, partially funded byNASA under the agency'sCommercial Orbital Transportation Services program. To create Cygnus, Orbital paired theMulti-Purpose Logistics Module, built byThales Alenia Space and previously used by theSpace Shuttle for ISS logistics, with a service module based on Orbital'sGEOStar, asatellite bus. The larger Enhanced Cygnus was introduced in 2015. Orbital Sciences was renamedOrbital ATK in 2015 andNorthrop Grumman purchased Orbital in 2018 and has continued to operate Cygnus missions.
Cygnus NG-21 is the tenth Cygnus mission under theCommercial Resupply Services-2 contract.
Production and integration of Cygnus spacecraft are performed in Dulles, Virginia. The Cygnus service module is mated with the pressurized cargo module at the launch site, and mission operations are conducted from control centers inDulles, Virginia andHouston,Texas.[1]
The NG-21 spacecraft was named theS.S.Francis R. "Dick" Scobee in honor of the NASA astronaut who died in theSpace ShuttleChallenger disaster.[2] This is the sixteenth flight of the Enhanced-sized Cygnus PCM.[3][4]
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The Cygnus spacecraft was loaded with a total of 3,857 kilograms (8,503 lb) of cargo and supplies before its launch, including 3,843 kilograms (8,472 lb) of pressurised and 14 kilograms (31 lb) of unpressurised cargo.
The cargo manifest is broken down as follows:[5]
A repair kit for theNICER telescope will be delivered to the station on this mission.[6]
Due to issues withBoeing Crew Flight Test, the manifest was changed to transfer additional crew supplies to the ISS for the additional astronauts (six US astronauts rather than the expected four).[7]
Several scientific investigations were sent to the ISS aboard the Cygnus. These are four of the projects highlighted by NASA:
"Packed Bed Reactor Experiment: Water Recovery Series" will evaluate gravity's effects on eight test articles.Packed bed reactors are systems that use materials such as pellets or beads packed inside a structure to increase contact between different phases of fluids, such as liquid and gas. These reactors are used for various applications, including water recovery, thermal management, and fuel cells. Scientists previously tested the performance in space of glass beads, Teflon beads, a platinum catalyst, and other packing materials. Results could help optimize the design and operation of packed bed reactors for water filtration and other systems in microgravity and on the Moon and Mars. Insights from the investigation also could lead to improvements in this technology for applications on Earth such as water purification and heating and cooling systems.[8]
"STEMonstrations Screaming Balloon" is an educational demonstration using a balloon, a penny, and a hexagonal nut (the kind used to secure a bolt). The penny and the nut are whirled separately inside an inflated balloon to compare their sounds. NASA's STEMonstration program are educational lessons illustrating a different scientific concept performed and recorded by astronauts on the space station and include resources to help teachers further explore the topics with their students.[8]
"In-Space Expansion of Hematopoietic Stem Cells for Clinical Application" (InSPA-StemCellEX-H1) continues testing a technology to produce humanhematopoietic stem cells (HSCs) in space. HSCs give rise to blood and immune cells and are used in therapies for patients with certain blood diseases, autoimmune disorders, and cancers.
The investigation uses a system called BioServe In-space Cell Expansion Platform (BICEP), which is designed to expand HSCs three hundredfold without the need to change or add new growth media. BICEP affords a streamlined operation to harvest and cryopreserve cells for return to Earth and delivery to a designated medical provider and patient.
This investigation demonstrates whether expanding stem cells in microgravity could generate far more continuously renewing stem cells. This work eventually could lead to large-scale production facilities, with donor cells launched into orbit and cellular therapies returned to Earth. The biotechnology investigation also seeks to improve therapies for blood diseases and cancers such asleukemia.[8]
"Rotifer-B2", an ESA (European Space Agency) investigation, explores how spaceflight affects DNA repair mechanisms in a microscopicbdelloid rotifer,Adineta vaga. These tiny but complex organisms are known for their ability to withstand harsh conditions, including radiation doses 100 times higher than human cells can survive. The organisms are dried, exposed to high radiation levels on Earth, and rehydrated and cultured in an incubator on the station.
Previous research indicates that rotifers repair their DNA in space with the same efficiency as on Earth, but that research provided only genetic data. This experiment will provide the first visual proof of survival and reproduction during spaceflight. Results could provide insights into how spaceflight affects the rotifer's ability to repair sections of damaged DNA in a microgravity environment and could improve the general understanding of DNA damage and repair mechanisms for applications on Earth. This mission also delivers plants for the APEX-09 investigation, which examines plant responses to stressful environments and could inform the design of bio-regenerative support systems on future space missions.[8]
While most Cygnus missions have been launched atop Northrop Grumman'sAntares rocket from theMid-Atlantic Regional Spaceport, NG-21 was the second of three missions planned to launch atop theFalcon 9 Block 5 rocket from theCape Canaveral Space Force Station.
Northrop Grumman exhausted the supply of itsAntares 230+ rocket after the NG-19 mission. The Antares used a Russian-built engine and Ukrainian-built first stage, and production ceased after theRussian invasion of Ukraine. Northrop Grumman expects its next-generationAntares 300 rocket that does not depend on Ukrainian or Russian parts to be ready to fly NG-23 in August 2025. As an interim solution, Northrop Grumman contracted with its CRS competitorSpaceX to launch NG-20, 21 and 22 using its Falcon 9 rocket.
To accommodate the Cygnus, SpaceX modified theirpayload fairing to add a 5 ft × 4 ft (1.5 m × 1.2 m) side hatch to load late cargo onto the spacecraft from the cleanroom located at the end of the crew access arm installed atSpace Launch Complex 40.[9] The mission usedFalcon 9 first-stage booster #1080 on its tenth mission.
The rocket was first scheduled to lift off on 3 August 2024 at 15:28:00 UTC (11:29 am EDT, local time at the launch site) but was scrubbed due to poor weather conditions. The launch was rescheduled and successfully lifted off on 4 August 2024 at 15:02:23 UTC (11:02 am EDT). The first stage successfully touched down atLanding Zone 1 at the end of its flight.
After Cygnus separated from the Falcon's second stage, the spacecraft missed its first scheduled burn at 15:44 UTC due to a late entry to burn sequencing. The burn was rescheduled for 16:34 UTC, but was aborted when engine sensors registered low initial pressure. The Cygnus deployed its two solar arrays at 18:21 UTC as Northrop Grumman engineers investigated the issues.[10] The pressure reading was determined to be acceptable, and the Northrop Grumman was able to command the Cygnus to make two burns to put it on a trajectory to meet the station at the previously scheduled time.[11]
NASA astronautMatthew Dominick captured Cygnus usingthe station's robotic arm on 6 August 2024 at 07:11 UTC[12] and the spacecraft was berthed to theUnity module'snadir (Earth-facing) port at about 09:33 UTC.[13]
On 22 August, the Cygnus engine was fired for over 19 minutes to raise the orbital altitude of the ISS to 418.4 by 415.0 kilometres (260 by 257.9 mi). These periodic "reboosts" counteract atmospheric drag on the station.[14] The Cygnus has been available to do reboosts on an as-needed basis since theNG-17 mission,[15] after being successfully demonstrated on flightOA-9E. Russia's Progress cargo spacecraft also regularly perform reboosts during missions to the ISS.[16]
The spacecraft departure is planned for 21 March 2025 at 11:15 UTC.[17]
Note: Times are local to the launch site (Eastern Daylight Time).
| Attempt | Planned | Result | Turnaround | Reason | Decision point | Weather go (%) | Notes |
|---|---|---|---|---|---|---|---|
| 1 | 3 Aug 2024, 11:29:00 am | Scrubbed | — | Weather | (T−01:00:43) | 50[18] | |
| 2 | 4 Aug 2024, 11:02:53 am | Success | 0 days 23 hours 34 minutes | 35[19] | Weather initially forecasted at 10%.[20] |
This article incorporates text from this source, which is in thepublic domain.
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