Author Topic: Progress on rapid booster reuse  (Read 175473 times)

Offline livingjw

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Re: Progress on rapid booster reuse
« Reply #60 on: 12/31/2019 10:08 pm »
Thank you woods170.
I'll take that as occasional engine bell replacement then. The 'wild claim' might just be my poor memory as I didn't record it, but I don't think I was that far out.
John's speculation about foreign object damage was interesting as I guess it is relevant to Lunar and Martian landing and launch.
Maybe I should start a thread about how to change an engine bell in near vacuum and low G and whether it's worth carrying a spare..:-)

The Merlin 1D booster engine's Main Combustion Chamber and bell nozzle are one piece. You cannot replace just the bell.

John

Offline john smith 19

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Re: Progress on rapid booster reuse
« Reply #61 on: 01/01/2020 01:53 pm »
Although that does sound like it would escalate relatively minor damage to the bell to an engine replacement event. Obviously the benefit is the improved strength of unitized construction and the lower weight of eliminating any joint hardware.
The Merlin 1D booster engine's Main Combustion Chamber and bell nozzle are one piece. You cannot replace just the bell.
« Last Edit: 01/01/2020 06:42 pm by Chris Bergin »
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Offline woods170

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Re: Progress on rapid booster reuse
« Reply #62 on: 01/01/2020 06:50 pm »
Thank you woods170.
I'll take that as occasional engine bell replacement then. The 'wild claim' might just be my poor memory as I didn't record it, but I don't think I was that far out.
John's speculation about foreign object damage was interesting as I guess it is relevant to Lunar and Martian landing and launch.
Maybe I should start a thread about how to change an engine bell in near vacuum and low G and whether it's worth carrying a spare..:-)

The Merlin 1D booster engine's Main Combustion Chamber and bell nozzle are one piece. You cannot replace just the bell.

John
That is entirely correct. Replacing a bell automatically means replacing the entire engine.
As I had already pointed out - in my previous post - the story about reuse requiring replacing the bells (and thus the entire engine) is false. It is just another one of many b*llshit stories thrown into the world to deliberately throw a false shade on the success of booster reuse.
« Last Edit: 01/01/2020 06:58 pm by woods170 »

Offline john smith 19

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Re: Progress on rapid booster reuse
« Reply #63 on: 01/02/2020 05:37 pm »
That is entirely correct. Replacing a bell automatically means replacing the entire engine.
As I had already pointed out - in my previous post - the story about reuse requiring replacing the bells (and thus the entire engine) is false. It is just another one of many b*llshit stories thrown into the world to deliberately throw a false shade on the success of booster reuse.
That is why I asked exactly where that comment was supposed to have been made. It's not even clear if that was the actual statement made as it was not recorded.

I think there is a lot of speculation about exactly what SX inspects and replaces given that it took a long time for NASA to stop doing it after every Shuttle flight (which is the only other reference point for reuse).  And outside the team in SX that does it no one actually knows the truth.

So much folklore and old wives tales abound in rocket engineering. IRL No liquid fuel rocket engine is ever ignited only on the launch stand when it takes its payload to orbit.  It's just so many have been designed for single use weapon systems that designers have gotten into the (bad) habit of designing single use parts that have to be replaced (or refilled in the case of the TEA tank, which is a very odd design choice for a reusable engine IMHO) after a firing.

Personally I'd be more worried about coking in the cooling channels with RP1. I'd definitely want a pressure sensor checking on that. OTOH coke buildup inside the GG might actually protect the walls better after a flight than during the first one.
MCT ITS BFR SS. The worlds first Methane fueled FFSC engined CFRP SS structure A380 sized aerospaceplane tail sitter capable of Earth & Mars atmospheric flight.First flight to Mars by end of 2022 TBC. T&C apply. Trust nothing. Run your own #s "Extraordinary claims require extraordinary proof" R. Simberg."Competitve" means cheaper ¬cheap SCramjet proposed 1956. First +ve thrust 2004. US R&D spend to date > $10Bn. #deployed designs. Zero.

Offline rakaydos

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Re: Progress on rapid booster reuse
« Reply #64 on: 01/06/2020 06:04 pm »
I then realised that a launch failure is likely to cause a six month launch hiatus whatever the reason for launch failure … .
What would prevent SpaceX doing an internal, Starlink launch shortly after a failure?  Isn't it mostly SpaceX's call on whether they want to take the risk?

Delay may be the NASA/DoD way, but how much say do they get when they are not the customer?  The FAA appears to mostly care about not hurting bystanders, and the normal launch procedures should see to that (or they would object to things like in flight abort tests.)

I would imagine something like, "Regularly schedualed rideshares to SSO will continue during the investigation, though we will waive rebooking fees for any customer who wishes to delay. We will make the results of our investigation known after it's completion."

let people make informed choices with their payloads, fill empty slots with Starlink.

Offline Norm38

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Re: Progress on rapid booster reuse
« Reply #65 on: 01/08/2020 01:44 pm »
Maybe this is the best place to ask this question, rather than in a Starlink thread or in a stand-alone thread.

Is it possible that SpaceX will eliminate static fires for Starlink launches?

Per what we've been told, SpaceX plans to launch Starlink every two weeks.  At that pace, static fires become a significant portion of the workload and schedule.  Booster reflights are common now, the IFA will be the 3rd 4th flight.

I'm not aware of the static fires catching any issues in a long time (correct me if I'm wrong).  Is SpaceX reaching the point where static fires are not useful enough to continue?  Another cycle on tanks and engines that doesn't put payload on orbit.
I can see them rolling the dice on Starlink launches and going straight to launch.

What do you guys think?

Offline whitelancer64

Re: Progress on rapid booster reuse
« Reply #66 on: 01/08/2020 02:45 pm »
Maybe this is the best place to ask this question, rather than in a Starlink thread or in a stand-alone thread.

Is it possible that SpaceX will eliminate static fires for Starlink launches?

Per what we've been told, SpaceX plans to launch Starlink every two weeks.  At that pace, static fires become a significant portion of the workload and schedule.  Booster reflights are common now, the IFA will be the 3rd 4th flight.

I'm not aware of the static fires catching any issues in a long time (correct me if I'm wrong).  Is SpaceX reaching the point where static fires are not useful enough to continue?  Another cycle on tanks and engines that doesn't put payload on orbit.
I can see them rolling the dice on Starlink launches and going straight to launch.

What do you guys think?

ULA eliminated the WDR (Wet Dress Rehearsal) from its Atlas launch campaigns, except for high profile launches (like to Mars, crew flights, etc.), several years ago for that very reason, they weren't finding issues by doing them.
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Offline john smith 19

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Re: Progress on rapid booster reuse
« Reply #67 on: 01/09/2020 06:07 am »
ULA eliminated the WDR (Wet Dress Rehearsal) from its Atlas launch campaigns, except for high profile launches (like to Mars, crew flights, etc.), several years ago for that very reason, they weren't finding issues by doing them.
I'm interested in what proportion of ULA flights they deem "high profile," and wheather they also caught any anomalous behavior.

It is interesting that a company that only flies fully expendable LV's should feel they are confident enough in their processes (and the build quality and existing sub system tests) that they no longer regard this as essential.

For SX I'd have said the static fire would be the few seconds before launch. A key benefit of LRE's being if you do pick something odd you can still shut the launch down. Not something you can do easily once SRB's are involved.
MCT ITS BFR SS. The worlds first Methane fueled FFSC engined CFRP SS structure A380 sized aerospaceplane tail sitter capable of Earth & Mars atmospheric flight.First flight to Mars by end of 2022 TBC. T&C apply. Trust nothing. Run your own #s "Extraordinary claims require extraordinary proof" R. Simberg."Competitve" means cheaper ¬cheap SCramjet proposed 1956. First +ve thrust 2004. US R&D spend to date > $10Bn. #deployed designs. Zero.

Offline envy887

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Re: Progress on rapid booster reuse
« Reply #68 on: 01/09/2020 01:19 pm »
ULA eliminated the WDR (Wet Dress Rehearsal) from its Atlas launch campaigns, except for high profile launches (like to Mars, crew flights, etc.), several years ago for that very reason, they weren't finding issues by doing them.
I'm interested in what proportion of ULA flights they deem "high profile," and wheather they also caught any anomalous behavior.

It is interesting that a company that only flies fully expendable LV's should feel they are confident enough in their processes (and the build quality and existing sub system tests) that they no longer regard this as essential.

For SX I'd have said the static fire would be the few seconds before launch. A key benefit of LRE's being if you do pick something odd you can still shut the launch down. Not something you can do easily once SRB's are involved.

A SF in the seconds before launch is not a SF. It's already the standard launch procedure, where the engines are spun up and have to meet health checks before the clamps release.

SF is for schedule. If it's hurting the schedule more than helping it, it will go.

Offline meekGee

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Re: Progress on rapid booster reuse
« Reply #69 on: 01/12/2020 04:42 am »
ULA eliminated the WDR (Wet Dress Rehearsal) from its Atlas launch campaigns, except for high profile launches (like to Mars, crew flights, etc.), several years ago for that very reason, they weren't finding issues by doing them.
I'm interested in what proportion of ULA flights they deem "high profile," and wheather they also caught any anomalous behavior.

It is interesting that a company that only flies fully expendable LV's should feel they are confident enough in their processes (and the build quality and existing sub system tests) that they no longer regard this as essential.

For SX I'd have said the static fire would be the few seconds before launch. A key benefit of LRE's being if you do pick something odd you can still shut the launch down. Not something you can do easily once SRB's are involved.

A SF in the seconds before launch is not a SF. It's already the standard launch procedure, where the engines are spun up and have to meet health checks before the clamps release.

SF is for schedule. If it's hurting the schedule more than helping it, it will go.
SFs are SFs iff there's a chance for review that is not available during the hold-down of a real launch.  This review can be manual or automated, it doesn't matter.

IMO SFs will go once SpaceX feels that data from the previous launch can replace them.  New boosters will therefore still get SFs.
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Offline john smith 19

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Re: Progress on rapid booster reuse
« Reply #70 on: 01/12/2020 09:51 am »
A SF in the seconds before launch is not a SF. It's already the standard launch procedure, where the engines are spun up and have to meet health checks before the clamps release.

SF is for schedule. If it's hurting the schedule more than helping it, it will go.
That sounds likely.
SFs are SFs iff there's a chance for review that is not available during the hold-down of a real launch.  This review can be manual or automated, it doesn't matter.
Good point, and of course it means you have to have some data from a correctly functioning vehicle to compare it against.
Quote from: meekGee
IMO SFs will go once SpaceX feels that data from the previous launch can replace them.  New boosters will therefore still get SFs.
That sounds quite plausible, unless their consistency is so good they can designate a particular stage (or engine) and simply compare all future stages and engines against these archetypal test sets.

Again a small but significant step on the way to space launch being more like every other transportation system on the planet.

MCT ITS BFR SS. The worlds first Methane fueled FFSC engined CFRP SS structure A380 sized aerospaceplane tail sitter capable of Earth & Mars atmospheric flight.First flight to Mars by end of 2022 TBC. T&C apply. Trust nothing. Run your own #s "Extraordinary claims require extraordinary proof" R. Simberg."Competitve" means cheaper ¬cheap SCramjet proposed 1956. First +ve thrust 2004. US R&D spend to date > $10Bn. #deployed designs. Zero.

Offline wannamoonbase

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Re: Progress on rapid booster reuse
« Reply #71 on: 01/14/2020 12:35 pm »

IMO SFs will go once SpaceX feels that data from the previous launch can replace them.  New boosters will therefore still get SFs.

Agreed, with lower flight cores.  But with the increase in flights per core they have a long way to go to baseline what a healthy booster looks like as they approach 10 flights each.

But with Starlink’s flight rate and busy schedule something may need to give.
Wildly optimistic prediction, Superheavy recovery on IFT-4 or IFT-5

Offline Norm38

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Re: Progress on rapid booster reuse
« Reply #72 on: 01/15/2020 02:36 am »
IMO SFs will go once SpaceX feels that data from the previous launch can replace them.  New boosters will therefore still get SFs.

A new booster will have just been fired in Texas.  So is the SF to check for damage during transport?  Setup damage?  If not, what else?

To launch every two weeks this year, the pad has to be robust already.  If SFs are needed to check out the pad, beef up the pad.

Online FutureSpaceTourist

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Re: Progress on rapid booster reuse
« Reply #73 on: 02/07/2020 12:57 pm »
https://www.teslarati.com/spacex-next-rocket-launch-new-booster-reuse-record/

Quote
SpaceX's next rocket launch on track to break a 20-month-old booster reusability record
By Eric Ralph
Posted on February 7, 2020

Scheduled as early as next week, SpaceX’s next rocket launch could see the company break a 20-month-old record that is closely intertwined with the reusability of its Falcon 9 and Falcon Heavy boosters.

[…]

Now, SpaceX wants to launch B1056 for the fourth time as early as February 15th. Close observers will note that that would imply just 61 days between B1056’s Kacific-1 and Starlink V1 L4 launches, a feat that would make it SpaceX’s fastest ‘booster turnaround’ ever.


Offline Stefan.Christoff.19

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Re: Progress on rapid booster reuse
« Reply #74 on: 02/07/2020 04:58 pm »
[quote

[…]

Now, SpaceX wants to launch B1056 for the fourth time as early as February 15th. Close observers will note that that would imply just 61 days between B1056’s Kacific-1 and Starlink V1 L4 launches, a feat that would make it SpaceX’s fastest ‘booster turnaround’ ever.[/quote]
[/quote]

Interesting decision to use 1056 on a record turnaround of 61 days vs. 1048 on 96 days (as of 2/15). That would have been a record 5th mission for 1048. Also they have definitely decided not to use the FH side boosters 1052-3 for a single stick use. Both are sitting at 227 days as of today. The info on the turnaround time also said they had 11 boosters at the Cape, but obviously not all used boosters are equally usable.

Offline ChrisWilson68

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Re: Progress on rapid booster reuse
« Reply #75 on: 02/07/2020 05:08 pm »
The info on the turnaround time also said they had 11 boosters at the Cape, but obviously not all used boosters are equally usable.

That's not obvious at all.

If they have lots of boosters to choose from, just because they choose to use booster A instead of booster B doesn't mean B isn't perfectly usable.  If all 11 of those boosters are perfectly usable, they have to choose some to use and some not to.  There might be very marginal differences.  They might choose to reuse a particular booster several times in a relatively short period just to show that they can.

We don't really know why they choose any particular booster for any particular launch, so we can't reasonably draw any conclusions from their choices.

Offline edkyle99

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Re: Progress on rapid booster reuse
« Reply #76 on: 02/07/2020 07:12 pm »
The info on the turnaround time also said they had 11 boosters at the Cape, but obviously not all used boosters are equally usable.

That's not obvious at all.

If they have lots of boosters to choose from, just because they choose to use booster A instead of booster B doesn't mean B isn't perfectly usable.  If all 11 of those boosters are perfectly usable, they have to choose some to use and some not to.  There might be very marginal differences.  They might choose to reuse a particular booster several times in a relatively short period just to show that they can.

We don't really know why they choose any particular booster for any particular launch, so we can't reasonably draw any conclusions from their choices.

If Falcon Heavy side boosters are not considered for Falcon 9 flights, SpaceX currently only has five previously-flown first stages on-hand.  They are 1048, 1049, 1051, 1056, and 1059.  These last flew on Nov 11, Jan 7, Jan 29, Dec 17, and Dec 5, respectively.  For me the puzzle is why they would fly 1056 before 1048 or 1059.

 - Ed Kyle
« Last Edit: 02/07/2020 07:13 pm by edkyle99 »

Online FutureSpaceTourist

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Re: Progress on rapid booster reuse
« Reply #77 on: 02/10/2020 07:16 pm »
https://twitter.com/thesheetztweetz/status/1226962206169948163

Quote
Euroconsult tracked SpaceX's reuse of Falcon 9 rocket boosters and found that the company has cut its turnaround time from ~250 days between flights to ~75 days between flights.

That's about a 70% reduction in reusability time:
spacenews.com/op-ed-spacexs-…

https://spacenews.com/op-ed-spacexs-adaptation-to-market-changes/

Online FutureSpaceTourist

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Re: Progress on rapid booster reuse
« Reply #78 on: 02/15/2020 04:00 pm »
Quote
Elon Musk’s SpaceX is about to land its 50th Falcon 9 booster

Once thought impossible, reusing rocket boosters has become routine

By
Christian Davenport
Feb. 14, 2020 at 8:21 p.m. GMT

The effort to return booster rockets to Earth had been tried and had failed several times; it turns out landing a rocket back on Earth safely is pretty difficult. So Elon Musk was not deluding himself in 2014 when he calculated the odds that his company, SpaceX, would eventually get it right: “not great — perhaps 50 percent, at best.”

https://www.washingtonpost.com/technology/2020/02/14/elon-musks-spacex-is-about-land-its-50th-falcon-9-booster/

Offline oldAtlas_Eguy

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Re: Progress on rapid booster reuse
« Reply #79 on: 02/16/2020 09:17 pm »
This next launch makes the turnaround for 3rd relaunch at 63 days which seems to be the average for turnaround for 1st relaunch.

Meaning taking it easy and no rushing turnaround is ~2 months so far through to 3rd reflight. Enough data seemingly has been collected to make SpaceX comfortable with a 2 month turnaround process that includes multiple flights sea landings.

Soon we should see 4th reflight since a backlog of 4 total flight boosters exits.
« Last Edit: 02/16/2020 09:38 pm by oldAtlas_Eguy »

 

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