![\"\"](\"https:\/\/www.nasaspaceflight.com\/wp-content\/uploads\/2021\/08\/13162A5F-16C1-4871-853D-6FBB38005E70-scaled.jpeg\")
<\/p>\nOn August 10, the S.S. Ellison Onizuka launched on an Antares 230+ rocket from Pad-0A at NASA\u2019s Wallops Flight Facility. The NG-16 countdown was hampered with helium and ground computer issues leading up to the final T0 mark.<\/p>\n
But teams at Northrop Grumman were able to launch at the end of the launch window at 18:01:05 EDT, or 22:01:05 UTC, with Antares performing a better-than-expected ascent to orbit for the Cygnus spacecraft.<\/p>\n<\/p>\n
Before launch:<\/p>\n
During the countdown, the launch team noted that a helium storage tank located adjacent to Pad-0A was leaking.<\/p>\n
\u201cWe monitor the pressures in all of those tanks, and we saw the pressure start to decrease precipitously out of the helium storage tank,\u201d said Kurt Eberly, Director Space Launch Programs, Northrop Grumman, in an interview with NASASpaceflight. <\/p>\n
Before the poll to start fuelling the first stage of the Antares rocket with RP-1 kerosene and liquid oxygen (LOX), the launch team decided to send the Red Team back to Pad-0A to fix the leak on the ground helium tank.<\/p>\n
The Red Team for Antares launches is made up of technicians and engineers from both Northrop Grumman and Virginia Space.<\/p>\n
<\/p>\n
NASA Associate Administrators Dr. Thomas Zurbuchen and Robert Cabana, along with NASA Administrator Bill Nelson attended the NG-16 launch. Credit: Thomas Burghardt for NASASpaceflight\/L2.<\/p>\n
For the Red Team to go back to Pad-0A, the launch conductor on console recommended that the team push the liftoff time, or T0, to the end of the planned 5 minute launch window. <\/p>\n
\u201cIn this kind of scenario, five minutes can be really successful for the team,\u201d said Eberly. \u201cThey identified a release valve that was leaking, and they were able to get it to reset. And then we were able to reopen the isolation valve to stop the leak and flow helium to the vehicle again to start loading up the pressure bottles.\u201d<\/p>\n
The successful work by the Red Team stabilized the pressure on the ground helium storage tank. After their work was done, they evacuated Pad-0A to their fallback location, which is the same building where the Cygnus spacecraft is fuelled with hydrazine.<\/p>\n
\u201cOne of the things we do is we load helium into the pressure bottles on stage one after the LOX starts loading in\u2026 this is kind of a common trick for LOX\/RP-1 stages where you cover the helium bottles, which are inside the LOX tank,\u201d said Eberly. \u201cWe covered them with LOX, and then they get cold and you can load the helium in.\u201d<\/p>\n
During the countdown, launch controllers were also able to lower the helium supply pressure constraint from 4,000 psi to 3,800 psi.<\/p>\n
\u201cIf we had to scrub\u2013 we do use helium as part of the detanking process and to purge the engines as well. So that lower bound [pressure constraint of 4,000 psi] was intended to make sure that we can get through the detanking process safely and preserve the hardware in a flightworthy condition throughout the detanking process,\u201d said Eberly.<\/p>\n
![\"\"](\"https:\/\/www.nasaspaceflight.com\/wp-content\/uploads\/2019\/04\/BCK_2782-scaled.jpg\")
<\/p>\n
The might of Antares captured from remote camera of Brady Kenniston at the NG-11 launch. (Credit: Brady Kenniston for NSF\/L2)<\/p>\n
\u201cHaving done those calculations, we felt comfortable proceeding and moving the constraint down and proceeded on with the launch.\u201d <\/p>\n
At T-6 minutes 45 seconds, the NASA Test Director told the Launch Conductor they were \u201cno go\u201d due to a backup computer failure and that it would take 4 minutes to recycle the computer system.<\/p>\n
\u201cIt was a backup computer for their range safety displays,\u201d said Eberly. \u201cAnd that may not have actually been a constraint\u2026 that they were able to work through it\u2026 so we just proceeded on hoping that they were going to go green, and they did fortunately.\u201d <\/p>\n
Another potential issue the launch team kept aware of was a boat near the launch hazard area.<\/p>\n
\u201cThe range surveillance team picked up the radar track on that boat, and they were trying to make contact with them,\u201d said Eberly. \u201cThey thought that the boat was going to come \u2026 right across the launch hazard area. It turns out the boat was going somewhere else, so it turned out to not be an issue.\u201d<\/p>\n
NG-16 launch<\/p>\n
Despite the eventful countdown, the Antares rocket lifted off right at the end of the day\u2019s launch window.<\/p>\n