SpaceX is preparing to static fire test a Falcon 9 at the Vandenberg Air Force Base ahead of a mission to launch the next set of Iridium NEXT satellites. The test will set the stage for the potential of two launches within two days for SpaceX, as it realigns the launch date for the Falcon 9 that has already conducted a hot-fire test ahead of its BulgariaSat-1 mission.
Test, Test, Launch, Launch:
The previous plan was to launch the BulgariaSat-1 mission on Monday. However, an issue with a fairing valve resulted in SpaceX delaying the launch until NET (No Earlier Than) June 23.
The valve system – used to separate the two fairing halves that encapsulate and protect the payload during the initial phase – has redundancy built into the system. Elon Musk tweeted that it was “not worth taking a chance”, thus the valve is being replaced inside the 39A Horizontal Integration Facility (HIF).
The Falcon 9 had returned to the HIF following a successful seven second Static Fire test of its nine Merlin 1D engines and was undergoing the stack integration flow ahead of rollout when the issue was noted as part of the routine pre-rollout checks.
Interestingly, a surprise rollout of what is understood to be the same Falcon 9 took place on Monday evening, again – as is now common practice – without the payload.
While the identity of the booster has not been confirmed, the Falcon 9 was not expected to conduct a second static fire, based on the lack of required notices for KSC workers, per roadblocks and safety precautions relating to such tests. Sources also stress the original Static Fire test was without issue and the vehicle had passed its Launch Readiness Review (LRR).
While unconfirmed by SpaceX, it is understood the vehicle is at the pad to aid the testing of ground hydraulics in the 39A Ground Support Equipment (GSE) system. This element of the GSE has required some periodical work since 39A was reactivated for use with SpaceX launches.
With the launch delayed while engineers replace the valve on the fairing, the opportunity to use the rocket sat on the TEL with nothing to do for several days may have initiated this mooted Pad GSE test.
Once the Falcon 9 is back in the HIF, the pre-launch mating flow will take place ahead of rollout back up the 39A ramp – this time as an integrated stack – for launch within a two-hour window that opens at 14:10 local time on Friday.
Due to the delay to the BulgariaSat-1 mission, the next event for SpaceX is another Static Fire test, this time on the West Coast.
The Falcon 9 tasked with launching the next set of Iridium NEXT satellites will enjoy a 3.5-second firing on the SLC-4E pad at Vandenberg.
The window for the test was originally cited as 11 am local time, before it was realigned to target a T-0 of 1:30 pm local time. Static Fire tests have long windows to provide engineers an allowance for troubleshooting.
Confirmation of a good test will come via SpaceX on its social media channels, based on the results of the “quick look” data.
The SpaceX team will then head into the Launch Readiness Review (LRR) ahead of the Sunday launch attempt with the window opening at 13:25 pm local time.
SpaceX has the ability to continue the flow towards launch, despite the schedule change with the BulgariSat-1 pre-launch flow, due to two separate launch teams for its two – currently active – launch sites.
SpaceX’s mission control (MCC-X) in Hawthorne, California also holds the ability thanks to a recent configuration change that avoids any overlaps in procedures relating to the two individual missions taking place in close proximity.
These next two missions will set a record minimum gap between a pair of SpaceX launches, although due to the slip of the BulgariaSat-1 launch, a third closely schedule mission – with Intelsat 35e, which was scheduled to launch on July 1 – will obviously be pushed to the right.
That mission was working towards a June 26 Static Fire test. However, that is now impossible, with a set amount of days required for post launch activities that include safing the pad, conducting a Pad Shakedown Report – which documents and actions any required post-launch repairs to the pad – prior to the rollout of the next Falcon 9 set to launch from the historic pad.
Based on the minimum timeline – which has been achievable of late thanks to the superb performance of 39A during its SpaceX role – the flow for the Intelsat 35e mission is likely moving to the right on a day to day basis with the BulgariaSat-1 launch flow realignment.
While a new target date has yet to be filed with the Eastern Range for approval at the time of writing, these three upcoming launches are still set to mark a new launch manifest turnaround record for SpaceX, a sign of their improving launch cadence following the company’s return to flight after the loss of the Amos-6 payload and launch vehicle during a Static Fire test.
Notably, SLC-40 – which was largely destroyed in that accident – is showing signs it’s on the final leg towards re-activation. The biggest sign towards its return will be the sight of the new TEL (Transport/Erector/Launcher) at the pad. Parts of this hardware is understood to be already inside the SLC-40 HIF.
It is expected to be a version of the new TEL used at 39A, albeit catered for only Falcon 9 launches. The return to SLC-40 will free 39A’s TEL to be modified – as it was designed – for use with both Falcon 9 and Falcon Heavy rocket launches – the latter set to debut later this year.
(Images: SpaceX, Iridium and L2 – including a large collection of photos from this launch campaign via Brady Kennison for NASASpaceFlight.com)
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