Author Topic: F9 Block 5 Updates, Discussions, and Speculations  (Read 101976 times)

Offline Robotbeat

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Re: F9 Block 5 Updates, Discussions, and Speculations
« Reply #140 on: 03/11/2017 03:44 PM »
Semmel: Why would they only do 20 satellites per launch??? OneWeb is doing 80 on New Glenn, and Falcon Heavy has a bit more payload. Falcon Heavy is cheaper per kilogram than F9, and has less hardware expended per kilogram than F9 or New Glenn. For the same number of upper stages produced, SpaceX can launch almost 3x as much payload to LEO. And only have one fairing pair to recover (or build) instead of 3.

Seriously, stop with this artificial constraint of just 20 satellites per launch.
« Last Edit: 03/11/2017 03:47 PM by Robotbeat »
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Online FutureSpaceTourist

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Re: F9 Block 5 Updates, Discussions, and Speculations
« Reply #141 on: 03/11/2017 04:45 PM »
As SpaceX have recovered a load of boosters I get they can identify improvements for re-usability to include in B5. But they haven't yet re-used any boosters (although hopefully that's now just weeks away).

Do people think that seeing the wear on 7(?) recovered new boosters after 1 use is sufficient to infer what may happen after multiple uses of the same booster? Maybe incremental changes over the last year have meant that SpaceX are already seeing reduced wear/refurbishment needed and so can be confident they are closing in on the re-use improvements needed for B5?

Offline Robotbeat

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Re: F9 Block 5 Updates, Discussions, and Speculations
« Reply #142 on: 03/11/2017 04:51 PM »
Also, let's not pretend ITS isn't a thing. That's the whole reason that block 5 is the last F9.
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Online Semmel

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Re: F9 Block 5 Updates, Discussions, and Speculations
« Reply #143 on: 03/11/2017 05:27 PM »
Semmel: Why would they only do 20 satellites per launch??? OneWeb is doing 80 on New Glenn, and Falcon Heavy has a bit more payload. Falcon Heavy is cheaper per kilogram than F9, and has less hardware expended per kilogram than F9 or New Glenn. For the same number of upper stages produced, SpaceX can launch almost 3x as much payload to LEO. And only have one fairing pair to recover (or build) instead of 3.

Seriously, stop with this artificial constraint of just 20 satellites per launch.

No, I dont think so. If you accept the premise that F9B5 is the last version and nothing is allowed to change, FH will not help.

Maybe they will use FH for the internet constellation, but I wouldnt count on it. Because you would need a bigger fairing. I dont even think 20 sats will fit inside the current fairing. Also the current integration process has the payload suspended and raised on the fairing. Because of that, F9 or FH is not capable of launching more than 10 mT inside a fairing. Therefore, if you buy the premise that F9B5 will be frozen, a new fairing is off the books and FH will not help.

Offline Jim

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Re: F9 Block 5 Updates, Discussions, and Speculations
« Reply #144 on: 03/11/2017 05:34 PM »
And if Jim is right and F9B5 is the last version of F9, then meekGee is right and it will be a much larger leap forwards in recovery and refurbishment as well as the entire processing than is anticipated right now.

You are only half right.  The launch sites are basically at their final configurations.

Online macpacheco

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Re: F9 Block 5 Updates, Discussions, and Speculations
« Reply #145 on: 03/11/2017 06:04 PM »
Maybe they will use FH for the internet constellation, but I wouldnt count on it. Because you would need a bigger fairing. I dont even think 20 sats will fit inside the current fairing. Also the current integration process has the payload suspended and raised on the fairing. Because of that, F9 or FH is not capable of launching more than 10 mT inside a fairing. Therefore, if you buy the premise that F9B5 will be frozen, a new fairing is off the books and FH will not help.
You really think SX wouldn't build a bigger fairing to launch 4000 satellites ? I'm sure USAF would love to have a fairing that fits every planned DoD bird and plenty of room to grow. They didn't do it so far cause there wasn't economic justification. I wouldn't be surprised if DoD even pays 1/3 of the cost to build/certify the bigger fairing.

Also, let's not pretend ITS isn't a thing. That's the whole reason that block 5 is the last F9.
ITS is a thing, but ITS as announced is about 10x unnecessarily big for routine access to LEO/GTO. It will only make sense if SpaceX can launch GEO birds by the dozen.
A 1/4 scale ITS on the other hand would still be overkill but a much more reasonable overkill. Perhaps launching 30-40 tons worth of GEO birds at a time, into a zero inclination orbit with the perigee at least half way to GEO.
But that pretty much means SpaceX would take the entire GTO market ! One GTO flight every 3+ months. If you're flying any ways, and there's payload room left, how much do you charge to get one extra customer ? It might even make the GTO market into a zero reservation needed situation. Only book when you're ready to launch (assuming SX already knows your bus configuration).
Another way to think about it is reuse the standard ITS booster, but build a tiny (in comparison) 2nd stage customized for launch satellites only.
But I'm drifting very far off topic. Sorry  :-X
« Last Edit: 03/11/2017 06:12 PM by macpacheco »
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Offline Robotbeat

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Re: F9 Block 5 Updates, Discussions, and Speculations
« Reply #146 on: 03/11/2017 08:13 PM »
Semmel: Why would they only do 20 satellites per launch??? OneWeb is doing 80 on New Glenn, and Falcon Heavy has a bit more payload. Falcon Heavy is cheaper per kilogram than F9, and has less hardware expended per kilogram than F9 or New Glenn. For the same number of upper stages produced, SpaceX can launch almost 3x as much payload to LEO. And only have one fairing pair to recover (or build) instead of 3.

Seriously, stop with this artificial constraint of just 20 satellites per launch.

No, I dont think so. If you accept the premise that F9B5 is the last version and nothing is allowed to change, FH will not help.

Maybe they will use FH for the internet constellation, but I wouldnt count on it. Because you would need a bigger fairing. I dont even think 20 sats will fit inside the current fairing. Also the current integration process has the payload suspended and raised on the fairing. Because of that, F9 or FH is not capable of launching more than 10 mT inside a fairing. Therefore, if you buy the premise that F9B5 will be frozen, a new fairing is off the books and FH will not help.
False. We already KNOW that SpaceX is building a larger fairing. And these satellites are small. Around half a ton and thus probably less than a cubic meter in volume, you could probably fit in the existing fairing (though we already know SpaceX is building another fairing).

Who said "nothing is allowed to change"? Saying Block 5 is the last major variant of Falcon 9 is not the same as saying nothing (including the fairing) will change. At a minimum, I expect the fairing and probably the payload adapter to change. Also, we also know that SpaceX is pursuing some vertical integration capability.
« Last Edit: 03/11/2017 08:16 PM by Robotbeat »
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Offline Robotbeat

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Re: F9 Block 5 Updates, Discussions, and Speculations
« Reply #147 on: 03/11/2017 08:19 PM »
The EXISTING fairing has almost 160 cubic meters of volume. That's probably enough for 80 smallsats each less than a cubic meter in volume. But SpaceX is building another fairing.
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Offline old_sellsword

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Re: F9 Block 5 Updates, Discussions, and Speculations
« Reply #148 on: 03/11/2017 08:23 PM »
False. We already KNOW that SpaceX is building a larger fairing.

We know SpaceX is building a different fairing, we have no idea how big it is.

And these satellites are small. Around half a ton and thus probably less than a cubic meter in volume

Microsat 2a/b are 1.1m x 0.7m x 0.7m, so 0.54m3.

Online hkultala

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Re: F9 Block 5 Updates, Discussions, and Speculations
« Reply #149 on: 03/11/2017 08:40 PM »
The EXISTING fairing has almost 160 cubic meters of volume. That's probably enough for 80 smallsats each less than a cubic meter in volume.

Satellites are not liquid, they are solid. And there must be such support/release mechanism that holds them in a way that they survive the g-forces of the launch but can still be released.

Offline meekGee

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Re: F9 Block 5 Updates, Discussions, and Speculations
« Reply #150 on: 03/11/2017 08:52 PM »
Just consider that the much larger NG will only carry 80.

F9, IMO will end up with 20-30 per launch, or an orbital slot's worth.

Using FH doesn't change the equation much.  You have 3 cores refurbish instead of 1, but save on manufacturing S2s.

Plus, you can't RTLS the center core, so your "1 day" got expanded to 2 weeks.

We're looking at 1000 LEO sats per year, and at least 2000 VLEO sats per year, possibly much more if their life span is below 5 years, which IMO is likely.
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Offline Robotbeat

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Re: F9 Block 5 Updates, Discussions, and Speculations
« Reply #151 on: 03/11/2017 09:39 PM »
Just consider that the much larger NG will only carry 80.

F9, IMO will end up with 20-30 per launch, or an orbital slot's worth.

Using FH doesn't change the equation much.  You have 3 cores refurbish instead of 1, but save on manufacturing S2s.
Makes a pretty big difference. Might as well claim NG can only do 20-30 per launch (it also uses a ~5m fairing). NG's actual fairing is, if anything, just longer. Falcon's new fairing may well be just as long.

Quote
Plus, you can't RTLS the center core, so your "1 day" got expanded to 2 weeks.
It was never going to be a day with Falcon.
Quote

We're looking at 1000 LEO sats per year, and at least 2000 VLEO sats per year, possibly much more if their life span is below 5 years, which IMO is likely.
I would bet the opposite: lifespan closer to 7 years or more, i.e. Less replacement frequency.
« Last Edit: 03/11/2017 09:40 PM by Robotbeat »
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Offline Robotbeat

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Re: F9 Block 5 Updates, Discussions, and Speculations
« Reply #152 on: 03/11/2017 09:44 PM »
The EXISTING fairing has almost 160 cubic meters of volume. That's probably enough for 80 smallsats each less than a cubic meter in volume.

Satellites are not liquid, they are solid. And there must be such support/release mechanism that holds them in a way that they survive the g-forces of the launch but can still be released.
SpaceX has control over the fairing design, the spacecraft design, and the deployer design. They could build them conformal and load-bearing (like those Boeing satellite pairs) if they wanted to, filling up almost all the available space. They'd be doing a pretty crappy job if they couldn't manage better than 25% volumetric efficiency. They literally have almost 4 times as much volume as they'd need for 80 satellites.

If your argument starts with the assumption that SpaceX would be doing a really terrible job engineering the satellites to fit in a volume that they have control over, then it's not a very convincing argument.
« Last Edit: 03/11/2017 09:45 PM by Robotbeat »
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Offline RedLineTrain

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Re: F9 Block 5 Updates, Discussions, and Speculations
« Reply #153 on: 03/11/2017 09:53 PM »
The EXISTING fairing has almost 160 cubic meters of volume. That's probably enough for 80 smallsats each less than a cubic meter in volume. But SpaceX is building another fairing.

Do we know that it will be a bigger fairing?

Offline meekGee

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Re: F9 Block 5 Updates, Discussions, and Speculations
« Reply #154 on: 03/11/2017 09:57 PM »
Just consider that the much larger NG will only carry 80.

F9, IMO will end up with 20-30 per launch, or an orbital slot's worth.

Using FH doesn't change the equation much.  You have 3 cores refurbish instead of 1, but save on manufacturing S2s.
Makes a pretty big difference. Might as well claim NG can only do 20-30 per launch (it also uses a ~5m fairing). NG's actual fairing is, if anything, just longer. Falcon's new fairing may well be just as long.

Quote
Plus, you can't RTLS the center core, so your "1 day" got expanded to 2 weeks.
It was never going to be a day with Falcon.
Quote

We're looking at 1000 LEO sats per year, and at least 2000 VLEO sats per year, possibly much more if their life span is below 5 years, which IMO is likely.
I would bet the opposite: lifespan closer to 7 years or more, i.e. Less replacement frequency.

NG is a comparable rocket to FH, not to F9, and the statement by OneWeb said 80.  Take that as the only concrete data point we have. 

F9 will carry somewhere between 1/3 and 1/2 of that - at most.  Or else the oneWeb satellites are much larger than SpaceXs, and I always thought they were smaller.

--

Putting a satellite at VLEO is a huge challenge.  Highly corrosive environment, and enough drag to deorbit you quickly.  That's why even 5 years seems ambitious.  Of course you want more, but you can't always get what you want.

---

I still don't understand why you think FH will make a difference in terms of refurbishment.  It might carry more satellites (IF they are mass limited), but each FH is 3 cores, and one of them takes 2 weeks to get back.

It'll sure help with S2s, but it won't change the S1 launch rate.  It'll actually make it worse.

---

I'll add this:  IMO, SpaceX should (though they're saying they won't...) make a reusable integrated second stage/dispenser.  It'll have a serious mass penalty, and will likely require FH. 

However, there are no signs of them even entertaining something like that.
« Last Edit: 03/11/2017 09:58 PM by meekGee »
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Re: F9 Block 5 Updates, Discussions, and Speculations
« Reply #155 on: 03/11/2017 09:58 PM »
No matter if they use FH or F9, they'll need more than just OCISLY.
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Re: F9 Block 5 Updates, Discussions, and Speculations
« Reply #156 on: 03/11/2017 10:04 PM »
None of this has much if anything to do with Block 5 ...
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Offline watermod

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Re: F9 Block 5 Updates, Discussions, and Speculations
« Reply #157 on: 03/11/2017 10:47 PM »
None of this has much if anything to do with Block 5 ...

I saw in some other venues that SpaceX was looking at high performance rad hardened processors.
I assume for the ITS or the sat network but any chance of putting in triplets of rad hardened processors to replace the triple redundancy commercial processors in the current F9 boosters?
(I haven't seen any info how well the current triplets work in the boosters after landing.   Same for the dragon capsules)

Offline old_sellsword

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Re: F9 Block 5 Updates, Discussions, and Speculations
« Reply #158 on: 03/11/2017 10:49 PM »
None of this has much if anything to do with Block 5 ...

I saw in some other venues that SpaceX was looking at high performance rad hardened processors.
I assume for the ITS or the sat network but any chance of putting in triplets of rad hardened processors to replace the triple redundancy commercial processors in the current F9 boosters?
(I haven't seen any info how well the current triplets work in the boosters after landing.   Same for the dragon capsules)

Why would F9 S1 need rad hardened electronics?

Offline watermod

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Re: F9 Block 5 Updates, Discussions, and Speculations
« Reply #159 on: 03/11/2017 11:06 PM »
None of this has much if anything to do with Block 5 ...

I saw in some other venues that SpaceX was looking at high performance rad hardened processors.
I assume for the ITS or the sat network but any chance of putting in triplets of rad hardened processors to replace the triple redundancy commercial processors in the current F9 boosters?
(I haven't seen any info how well the current triplets work in the boosters after landing.   Same for the dragon capsules)

Why would F9 S1 need rad hardened electronics?

No idea if it does have any need.   That's why I mentioned assuming it is for ITS or the sat network.  Just that I haven't heard any reports on the survival of the current electronics after a flight and landing.  Same for the Dragons.

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