SpaceX has conducted what is hopefully the final major milestone ahead of their ORBCOMM OG2 mission from Cape Canaveral. The Static Fire test, conducted at 3pm local time on Friday, should – pending a review – realign the the Falcon 9 v1.1 rocket with a launch of the satellites in window that opens at 09:21 local time on Monday.
SpaceX Static Fire:
It’s been a relatively troublesome flow for this Falcon 9, as much as the tweaking on the ground is a far more preferable scenario than having to deal with them half way through first stage ascent.
Finding such issues with the rocket are usually discovered during major elements of a vehicle’s flow, such as testing at the McGregor test facility in Texas, or at the Cape.
The Cape testing, conducted inside the Hanger and out on the SLC-40 Pad, is designed to clear the rocket for launch.
One of the primary elements to ensure the rocket is ready to go in a Falcon 9 flow is the Static Fire.
Also known as the Hot Fire test, the effort relates to ensuring that the pad’s fueling systems – and the launch vehicle – function properly in a fully operational environment, with numerous requirements to be successfully proven via such a test, such as the engine ignition and shut down commands, which have to operate as designed, and that the Merlin 1D engines perform properly during start-up.
Tasks also include a full propellant loading sequence, launch countdown operations, engine ignition operations and testing of the pad’s high volume water deluge system.
The Static Test provides a dress rehearsal for the actual launch, with controllers first conducting a poll to allow for the loading of Falcon 9′s RP-1 propellant with liquid oxygen oxidizer two hours and thirty five minutes before T-0.
This was followed with fuel and Thrust Vector Control (TVC) bleeding on the second stage, performed at T-1 hour.
At T-13 minutes, a final flight readiness poll was required, with a final hold point at T-11 minutes.
Per the countdown procedures, the tasks then entered the terminal count ten minutes before ignition, followed by the launch vehicle being transferred to internal power at four minutes and forty six seconds before T-0.
The Flight Termination System (FTS), used to destroy the rocket in the event of a problem during an actual launch, was armed three minutes and eleven seconds before launch, and seven seconds later oxidizer topping was concluded.
Pressurization of the propellant tanks followed, and while a Wet Dress Rehearsal (WDR) – which are no longer required for the Falcon 9 – would have concluded the test at around T-5 seconds, the Static Fire continued the count through to ignition.
A short burst of the Merlin ID engines on the core stage of the F9 then took place – noted per L2 coverage – at 3pm local time, which allows for validation data to be gained on the health of the vehicle and pad systems.
With the required engine and vehicle data collected, detanking operations followed for the rest of the day, followed by the lowering on to the Transporter Erector and rollback to the hanger.
While the Static Fire needs to be reviewed by controllers, a thumbs up from engineers will confirm the vehicle has gotten past her previous issues – one of which related to the problem surrounding the rocket’s helium pressurization system that scrubbed a previous Static Fire.
Notably, that previous test allowed SpaceX to attempt to launch this Falcon 9 v1.1 last month. However, following a second stage issue on the first attempt and a weather scrub on the second, the following day brought up another hardware issue.
While the attempt was a long shot – based on the poor weather throughout what was an extended launch window – a problem with what was described by L2 sources as a TVC actuator on the rocket’s first stage was classed as a “potential concern”, resulting in a scrub being called for the day.
With another element coming into play – namely the Eastern Range and its requirement for a maintenance period – SpaceX decided it would be prudent to realign the launch into July.
With July 14 looking good, a positive review of the Static Fire test will be followed by a Launch Readiness Review (LRR) to confirm Monday’s attempt.
Monday’s attempt has a window that ranges from 09:21 to 11:55 local time, with a back up date on Wednesday, which has its launch window set for 08:36 through to 11:09 local time.
(Images: via SpaceX and Jacques van Oene/Spacepatches.nl).
(Click here: http://www.nasaspaceflight.com/l2/ – to view how you can support NSF and access the best space flight content on the entire internet)/