SpaceX has said they will take the recovered CRS-8 Falcon 9 first stage and test fire it 10 times at LC-39A.

There is lots of discussion as to what that means.

  • 10 full 2+ minute duration fires?
  • 10 3 second test fires?
  • One after another?
  • Days apart?
  • NASA Style, and take 3 years to get all 10 tests done?

These things may not be knowable in advance, due to confidentiality within SpaceX.

But one hint as the rapidity of the testing might be hinted at by the capacity of the deluge system used in each test fire.

What is the capacity of the deluge system, and how fast can it be refilled?

If the entire system is dumped on each test, and requires 2 days to refill from its water source, then we now they cannot do rapid tests in a row.

If the deluge system water is collected in settling pools that need time to be absorbed into the ground, then that may be a limit as well.

Thus the question is, what is the timeline for resetting the LC-39A deluge system between uses? If you happen to have data for any other launch pad, ask the question standalone, answer, and link back and forth to this please.


2 Answers 2


Edit: SpaceX had several testfires of the recovered CRS-8 Falcon 9 first stage at one-day intervals.

old: Capacity is 300k gallons (1135 tons), flowrate of up to 900 kgallon/min. For a Shuttle launch, those numbers suggest they emptied the reservoir for every launch, in 20-30 seconds (T-10 to T+20, give or take a few).

70% of the water evaporates. The remaining 30% is caught in two ponds, where it has to be treated before it can be pumped out, depending on the launcher: the ponds contain combustion products. The Shuttle SRB exhaust was toxic. IDK if that's an issue with kerosene.

For Falcon 9 FT, thrust is about 1/5 of the Shuttle's thrust. I expect this means they can reduce the flowrate by 80%.

Another approach:

For the JCSAT-14 launch, SpaceX had a static test fire on May 1, followed by a launch on May 5. Both on SLC-40.

  • $\begingroup$ What is the refill rate, which is the critical piece... So perhaps they can use the existing tankage 5 times before needing a refill. Obviously they would start refilling immediatly, but it would still take time. This would clearly limit the retest rate to 5 tests + refill rate for 5 more. $\endgroup$
    – geoffc
    May 5, 2016 at 16:16
  • $\begingroup$ Haven't found a refill rate. One website said the water was deionized, which would require preprocessing so they'd probably truck it in. If they use tap water, it depends on water mains capacity and pump capacity (to get it to the top of the tower). $\endgroup$
    – Hobbes
    May 5, 2016 at 19:10
  • $\begingroup$ 1100 tons of water only requires a tank size of a bit over a 10m cube. If it ever is a problem, building additional storage shouldn't be too demanding. $\endgroup$
    – Mike H
    May 6, 2016 at 7:40

Watching the SpaceX launch of SES-9, I noticed the water system is activated at T-8s, if not earlier. SpaceX has the capability of doing a launch after a last minute scrub. I would say given that fact, they can do at least 2 launches at once.

Bottom line, I don't think it will take months between test fires. In fact, I'm quite confident when they are ready they can do at least 2 a day, maybe even 3. The timeline is less sure, but it should be ready for a full launch anywhere from June to August. They might even wait for the SES launch scheduled for September, but there's no guarantee of that.


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