Photo: NASA
(Article updated to include information from NASA and Dr. Jonathon McDowell 3PM August 5)
After a picture-perfect launch Sunday morning, Northrup Grumman’s Cygnus CRS-2 NG-21 (S.S. Francis R. “Dick” Scobee) spacecraft encountered issues with its solar power array and its single engine.
NASA announced yesterday that there were issues with the solar arrays that powered the spacecraft, and that it had burned its first orbital correction engine burn intended to put Cygnus on a path towards ISS.
The solar array issue has been rectified, according to NASA
Northrop Grumman’s Cygnus spacecraft completed the deployment of its two solar arrays at 2:21 p.m. EDT after launching at 11:02 a.m. Aug. 4 on a SpaceX Falcon 9 rocket from Space Launch Complex 40 at Cape Canaveral Space Force Station in Florida to the International Space Station for NASA.
NASA, August 4, 2024
Of equal concern is a problem with Cygnus’s engine, which experienced low pressure during its planned firing:
Shortly after launch, the spacecraft missed its first burn slated for 11:44 a.m. due to a late entry to burn sequencing. Known as the targeted altitude burn, or TB1, it was rescheduled for 12:34 p.m., but aborted the maneuver shortly after the engine ignited due to a slightly low initial pressure state. There is no indication the engine itself has any problem at this time.
Cygnus is at a safe altitude, and Northrop Grumman engineers are working a new burn and trajectory plan. The team aims to achieve the spacecraft’s original capture time on station, which is currently slated for 3:10 a.m. on Tuesday, Aug. 6.
NASA, August 4, 2024
August 5 Update From NASA, Dr. Jonathon McDowell and NASA
Around 3PM EDT, NASA gave the following update:
Northrop Grumman’s Cygnus spacecraft continues on its way to the International Space Station following launch at 11:02 a.m. EDT Aug. 4 on a SpaceX Falcon 9 rocket from Space Launch Complex 40 at Cape Canaveral Space Force Station in Florida. The Cygnus spacecraft completed the deployment of its two solar arrays at 2:21 p.m. the same day.
The Cygnus spacecraft has completed two delta velocity burns, and it remains on track for a capture by the space station’s robotic arm slated for 3:10 a.m. on Tuesday, Aug. 6. The spacecraft is in a safe trajectory, and all other systems are operating normally.
Shortly after launch on Sunday, the spacecraft performed as designed by cancelling a scheduled engine burn due to a slightly low initial pressure reading flagged by the Cygnus onboard detection system. Engineers at Northrop Grumman’s mission control center in Dulles, Virginia evaluated the pressure reading, confirmed it was acceptable and re-worked the burn plan to arrive at the space station on the originally planned schedule.
NASA, August 5, 2024
Dr. Jonathon McDowell of the Harvard–Smithsonian Center for Astrophysics and perhaps the most authoritative source concerning orbital objects also offered this update shortly after three today.
From all appearances, Northrup Grumman, IHI Aerospace and NASA have rectified the issues that seemed to imperil the NG-21 mission on its first full day in space. Hopefully, Cygnus’s problems are behind it, and the spacecraft will bring some much-needed supplies and items to ISS as planned.
About Cygnus’s Engine
Cygnus is an American cargo spacecraft designed for expendable logistics missions to the International Space Station (ISS). It features two main components: the Service Module (SM) and the Pressurized Cargo Module (PCM). The Service Module includes 32 thrusters for attitude control and a BT-4 main engine, which burns 800 kg (1,800 lb) of hypergolic propellants—hydrazine and nitrogen tetroxide.
The BT-4 engine, a pressure-fed liquid rocket engine, is developed and manufactured by IHI Aerospace of Japan. IHI Aerospace has manufactured and delivered over 200 bipropellant thrusters for spacecraft since the start of development in the 1980s.
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