Author Topic: SpaceX Falcon 9 - CRS-8 Dragon - NET April, 2016 - DISCUSSION  (Read 372498 times)

Offline kevinstout

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Wow,  the one slightly darker star made a surprising emotional impact.  Guess I am a fanboi

Offline J-V

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No barge in the patch. RTLS confirmed then?  ;)

Offline MattMason

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Has anyone heard or seen any indications whether or not SpaceX plans to do an RTLS recovery on CRS-8's S1?  I'd have to believe an RTLS is within the envelope of the latest F9 (notice I didn't give it a version number or anything... ;) ) considering the difference in total LEO capability between the latest F9 and the rocket used on prior CRS flights.

I haven't seen the customary links to radio frequency clearances and references to FAA and FCC approvals, etc., that we normally get three to four weeks prior to a scheduled launch, so I figured I'd ask...

If we use ORBCOMM-2 as a model, CCAFS and KSC will post a "Incoming!" exclusion zone warning for areas of the range as they did prior to this mission's returning F9--but I suspect you already know this.
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Offline kevin-rf

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No barge in the patch. RTLS confirmed then?  ;)
Maybe they solved the SSTO problem and it will sneak up on Florida from behind ;)
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Online Prettz

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No barge in the patch. RTLS confirmed then?  ;)
I had assumed it was known that RTLS was always possible for CRS missions. Was that not true?

Offline MattMason

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No barge in the patch. RTLS confirmed then?  ;)
I had assumed it was known that RTLS was always possible for CRS missions. Was that not true?

Possible, yes. Approved, no.

It was only with the ORBCOMM-2 mission that RTLS was first approved by the FAA and the range to Landing Zone 1. All other Falcon 9 returning booster test landing attempts, CRS or otherwise, were deliberately soft-landed into the ocean if not given a ASDS for an barge landing.

The Powers That Be were convinced that, despite no successful ASDS landings to that date, that safety conditions were acceptable to let SpaceX try an LZ-1 landing for ORBCOMM-2.

So with that successful landing and with CRS-8's flight profile not requiring high performance (more fuel required), it's possible that RTLS or ASDS landing will occur. But there's been no official word on which location will be used.
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Online ZachS09

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No barge in the patch. RTLS confirmed then?  ;)
I had assumed it was known that RTLS was always possible for CRS missions. Was that not true?

Possible, yes. Approved, no.

It was only with the ORBCOMM-2 mission that RTLS was first approved by the FAA and the range to Landing Zone 1. All other Falcon 9 returning booster test landing attempts, CRS or otherwise, were deliberately soft-landed into the ocean if not given a ASDS for an barge landing.

The Powers That Be were convinced that, despite no successful ASDS landings to that date, that safety conditions were acceptable to let SpaceX try an LZ-1 landing for ORBCOMM-2.

So with that successful landing and with CRS-8's flight profile not requiring high performance (more fuel required), it's possible that RTLS or ASDS landing will occur. But there's been no official word on which location will be used.

They'll probably announce whether or not an RTLS will be attempted on launch day. They did the same for Orbcomm-2.
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Offline edkyle99

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No barge in the patch. RTLS confirmed then?  ;)
I had assumed it was known that RTLS was always possible for CRS missions. Was that not true?
Can I ask where this assumption comes from?  To my knowledge, the payload mass cutoff point for return-to-launch-site first stage recovery has not been announced.  The Orbcomm payload was less than 2 tonnes to a 47 deg orbit.  A fully loaded CRS Dragon is going to weigh 10 tonnes, if not more, and is going to 51.6 deg.

 - Ed Kyle
« Last Edit: 03/10/2016 04:31 pm by edkyle99 »

Online Comga

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They'll probably announce whether or not an RTLS will be attempted on launch day. They did the same for Orbcomm-2.
But the ASDS Thread 3 will be tracking OCISLY to see if it is towed from port several days in advance.
it will also have updates on the status of the repairs.  If the hole is not patched, it is not being used, although the converse cannot be said with confidence.
It seems unlikely that they will dump the first stage in the ocean.  What kind of wastrels would dump a perfectly good booster in the ocean after just one use?  ;D
What kind of wastrels would dump a perfectly good booster in the ocean after just one use?

Offline Kabloona

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Here is what appears to be the FCC transmitter application for CRS-8. Although the mission is not named, the NET March 20 date is consistent with earlier planning for CRS-8, and the coordinates given for the boat/barge location are consistent with a launch azimuth to ISS.

https://apps.fcc.gov/oetcf/els/reports/STA_Print.cfm?mode=current&application_seq=69496&RequestTimeout=1000

As pointed out above, the decision whether to land on the barge or RTLS could be changed until close to launch, but the permit shows that a barge landing is under consideration...or at least it was when the application was filed, before the ASDS was damaged on the SES-9 mission.
« Last Edit: 03/10/2016 06:20 pm by Kabloona »

Offline AncientU

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The damage to Of Course I still Love You appears to be a 'surface blemish' if that small hole in the deck is the biggest concern.
A day of welding and some paint(optional), and she's good to go. 
Barge repair =/= rocket science.
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Offline the_other_Doug

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Has anyone heard or seen any indications whether or not SpaceX plans to do an RTLS recovery on CRS-8's S1?  I'd have to believe an RTLS is within the envelope of the latest F9 (notice I didn't give it a version number or anything... ;) ) considering the difference in total LEO capability between the latest F9 and the rocket used on prior CRS flights.

I haven't seen the customary links to radio frequency clearances and references to FAA and FCC approvals, etc., that we normally get three to four weeks prior to a scheduled launch, so I figured I'd ask...

If we use ORBCOMM-2 as a model, CCAFS and KSC will post a "Incoming!" exclusion zone warning for areas of the range as they did prior to this mission's returning F9--but I suspect you already know this.

Of course I do.  ;)  I was just thinking that, at about this timeframe prior to the Orbcomm RTF, we were starting to see signs and hear rumors that they would attempt an RTLS.  ISTR it was about two weeks prior to RTF that it began to be discussed, based on public-access FAA and FCC applications.

I was only noting that we hadn't heard much in the rumor mill and the only FCC application, AFAIK, was/is for the barge comms.  (Of course, the same application was made for Orbcomm, too -- they held out the ASDS option until the last-minute decision was made.)  I was just wondering if anyone had heard anything (and not just for L2 consumption) either way.

Also, in terms of discussion, does anyone think that the failure of the Jason and SES-9 stage recoveries would provide a basis for FAA refusal of another RTLS attempt until at least one ASDS attempt is successful?  SES-9 was thought to be a real long shot, so that ought not count against SpaceX, but d'you think the FAA might want to see a successful ASDS landing in which there are no landing gear, guidance or propulsion malfunctions before they issue another RTLS permit?  Or do you think the one-for-one performance in RTLS thus far means they'll rubber-stamp such a request?

Where in that continuum do y'all think we lie right now?
-Doug  (With my shield, not yet upon it)

Offline Kabloona

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Also, in terms of discussion, does anyone think that the failure of the Jason and SES-9 stage recoveries would provide a basis for FAA refusal of another RTLS attempt until at least one ASDS attempt is successful?  SES-9 was thought to be a real long shot, so that ought not count against SpaceX, but d'you think the FAA might want to see a successful ASDS landing in which there are no landing gear, guidance or propulsion malfunctions before they issue another RTLS permit?  Or do you think the one-for-one performance in RTLS thus far means they'll rubber-stamp such a request?

Where in that continuum do y'all think we lie right now?

I can't imagine RTLS permission being refused now with successful RTLS having been demonstrated.

The first RTLS attempt was permitted despite several previous crash landings on the ASDS, and the latest SES-9 attempt was even more of a long shot, both literally and figuratively.

If anything, the crashes on ASDS have shown that (1) the stage terminal guidance is excellent, and (2) damage from the stage coming in hot is relatively minimal, well within the limits of LZ-1 to handle. So in a perverse way, the crashes on ASDS may have helped bolster SpaceX's case that RTLS is relatively safe, even when things go wrong.

Offline Joffan

I assume, on the patch,  the blue blip on the ISS represents BEAM - is that placement reasonably accurate?
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Offline e of pi

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I assume, on the patch,  the blue blip on the ISS represents BEAM - is that placement reasonably accurate?
Node three aft, so that's roughly correct. See the diagram here, and imagine rotating it 180 degrees.

Offline MattMason

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Also, in terms of discussion, does anyone think that the failure of the Jason and SES-9 stage recoveries would provide a basis for FAA refusal of another RTLS attempt until at least one ASDS attempt is successful?  SES-9 was thought to be a real long shot, so that ought not count against SpaceX, but d'you think the FAA might want to see a successful ASDS landing in which there are no landing gear, guidance or propulsion malfunctions before they issue another RTLS permit?  Or do you think the one-for-one performance in RTLS thus far means they'll rubber-stamp such a request?

Where in that continuum do y'all think we lie right now?


I can't imagine RTLS permission being refused now with successful RTLS having been demonstrated.

The first RTLS attempt was permitted despite several previous crash landings on the ASDS, and the latest SES-9 attempt was even more of a long shot, both literally and figuratively.

If anything, the crashes on ASDS have shown that (1) the stage terminal guidance is excellent, and (2) damage from the stage coming in hot is relatively minimal, well within the limits of LZ-1 to handle. So in a perverse way, the crashes on ASDS may have helped bolster SpaceX's case that RTLS is relatively safe, even when things go wrong.

Concur. Also, the next-to-last ASDS attempt was successful...it was only a landing leg mechanical failure that caused the booster to fall over after the engines were off. SES-9 was known to be short on fuel, so SpaceX was enjoying their "X" as "Experimental" to test high-speed landings and what control authority would work. Data, data, data.
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Offline iamlucky13

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I would think the most important consideration in approving RTLS attempts is not the fact that one landed successfully, but the fact that all of their attempts terminated within a radius significantly smaller than the distance from LZ-1 to anything that the Air Force would regret letting SpaceX hit.

Looked at another way, even if they crashed 10 in a row, but all ten were within 50 meters of the aim point, there's a pretty decent expectation the next one will be within 50 meters, too, and a good chance of an RTLS attempt approval.

On the other hand, if they landed 10 in a row, but one of the ten landed on General Monteith's car in the CCAFS parking lot, there would be some explaining to do before the good general lets them try to land a rocket at his base again.

Offline the_other_Doug

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Thanks for the intelligent discussion of the likelihood that the FAA and CCAFS will allow an RTLS on CRS-8.  This is exactly the kind of thing I was looking to establish, before people went off on why or why not an RTLS would be approved.

Good to get good facts established early on this forum, I think... ;)
-Doug  (With my shield, not yet upon it)

Offline baldusi

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BTW, hypothetically speaking, they might go with barge landing rather then RTLS just because they want to have a succesful landing. The legs are the new FT design and there's plenty of margin. In other words, even a barge landing would not prove that they can't do a RTLS on CRS missions.

Offline CyndyC

I assume, on the patch,  the blue blip on the ISS represents BEAM - is that placement reasonably accurate?
Node three aft, so that's roughly correct. See the diagram here, and imagine rotating it 180 degrees.

That's interesting to know some of the layers are Kevlar, and that the surface structure is flexible.
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