Making Synapses · Bringing Knowledge to Mankind
SpaceHolds, Recycles and Scrubs
Twenty flashcards on planned holds, the Artemis II terminal count hold rules and what the law asks after a countdown abort.
Free to startYour progress here is temporary and is lost when you close this page. Install Making Synapses free to keep it, with spaced repetition.
20 cards
- What is a built-in hold?
- A planned pause in the countdown to finish tasks, verify readiness and fix minor issues without hurting the timeline.
- How long was the planned built-in hold before Artemis II crew ingress?
- 1 hour and 10 minutes.
- What data do engineers review during that hold?
- Data from cryogenic loading, propulsion systems and communications.
- When did the Artemis II launch countdown begin?
- Monday at 4:44 p.m. EDT.
- How long was the Artemis II launch window?
- Two hours.
- Why did the Artemis II team extend the T-10 minute hold?
- To give engineers time to work through final preparations for liftoff.
- When did the Artemis II window open, and when did it lift off?
- The window opened at 6:24 p.m. EDT; liftoff came at 6:35 p.m. EDT.
- How long can the team hold at T-6 minutes?
- For the whole window, less the 6 minutes needed to launch, without recycling back to T-10.
- If the clock stops between T-6 minutes and T-1 minute 30 seconds, how long can they hold and still resume?
- Up to 3 minutes, then resume the clock to launch.
- And if that hold needs more than 3 minutes?
- The countdown recycles back to T-10.
- What if the clock stops after T-1:30 but before the automated launch sequencer takes over?
- Teams can recycle back to T-10 and try again, if enough launch window remains.
- What happens if an issue stops the count after handover to the automated launch sequencer?
- The launch attempt for that day is concluded.
- What takes control when Artemis II enters terminal count?
- The ground launch sequencer, running a precise series of automated commands toward liftoff.
- Name actions the ground launch sequencer performs.
- Pressurizes propellant tanks, activates flight software, switches control to onboard systems and runs final health checks on thousands of sensors.
- Why is replenish mode needed after tanking?
- Super-cold propellants naturally boil off, so a continuous low-rate flow keeps the tanks at flight-ready levels.
- How much propellant goes into the SLS core stage?
- 700,000 gallons of super-cold liquid oxygen and liquid hydrogen.
- After a countdown abort or delay, what must Part 450 pre-flight procedures ensure?
- That the operator can return the vehicle to a safe state.
- If a rocket does not lift off after the command to initiate flight, what must happen to the vehicle?
- The operator must ensure the vehicle and any payload are in a safe configuration.
- In that case, what rule applies to the public?
- No public entry into identified hazard areas until the site is back to a safe condition.
- And what must stay working until the rocket is no risk of inadvertent flight?
- Any flight safety system, kept operational and verified.
Official sources
National Aeronautics and Space Administration (NASA)
Artemis II Launch Day Updates (April 1, 2026)
Federal Aviation Administration (FAA), via GovInfo (GPO)
14 CFR Part 450: Launch and reentry license requirements (CFR 2025 edition)
Making Synapses is not affiliated with, sponsored by or endorsed by NASA, the FAA, the Canadian Space Agency or any launch provider. Agency, mission and program names are named only to describe the content.