Author Topic: General Falcon and Dragon discussion (Thread 15)  (Read 28999 times)

Online Chris Bergin

Thread 15 (for general discussion on SpaceX's Falcon and Dragon vehicles.

Previous threads (now over 5 million views for these 14 SpaceX previous threads alone):

Thread 1:
https://forum.nasaspaceflight.com/index.php?topic=19228.0

Thread 2:
https://forum.nasaspaceflight.com/index.php?topic=22769.0

Thread 3:
https://forum.nasaspaceflight.com/index.php?topic=24179.0

Thread 4:
https://forum.nasaspaceflight.com/index.php?topic=25597.0

Thread 5:
https://forum.nasaspaceflight.com/index.php?topic=28006.0

Thread 6:
https://forum.nasaspaceflight.com/index.php?topic=29476.0

Thread 7:
https://forum.nasaspaceflight.com/index.php?topic=30385.0

Thread 8:
https://forum.nasaspaceflight.com/index.php?topic=31402.0

Thread 9:
https://forum.nasaspaceflight.com/index.php?topic=32719.0

Thread 10:
https://forum.nasaspaceflight.com/index.php?topic=33598.0

Thread 11:
https://forum.nasaspaceflight.com/index.php?topic=35364.0

Thread 12:
https://forum.nasaspaceflight.com/index.php?topic=36815.0

Thread 13:
https://forum.nasaspaceflight.com/index.php?topic=39180.0

Thread 14:
https://forum.nasaspaceflight.com/index.php?topic=41018.0

SpaceX news articles on this site:
Old: https://forum.nasaspaceflight.com/index.php?topic=21862.0 (links)

Then recent news articles, not linked above, as we moved to a tag group system:
All recent: https://www.nasaspaceflight.com/tag/spacex/


L2 SpaceX - Dedicated all-vehicle (Falcon to BFR/MCT) section:
https://forum.nasaspaceflight.com/index.php?board=60.0


NOTE: Posts that are uncivil (which is very rare for this forum), off topic (not so rare) or just pointless will be deleted without notice.

And no, this is not a ULA vs SpaceX (vs SLS, heh) thread. This is about general posts about Falcon and Dragon.

And for the love of Elon - please make your post worthwhile, formatted correctly (if you quote, link etc).

Offline Asteroza

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Re: General Falcon and Dragon discussion (Thread 15)
« Reply #1 on: 10/12/2018 07:06 am »
With the recent Soyuz mishap, an expected EVA at ISS to install batteries delivered by HTV may not happen soon. If the old batteries can't be placed in the HTV battery carrier before it leaves prior to the next cargo Dragon, can the HTV battery carrier be removed and stored, then installed ad hoc in cargo Dragon's trunk for removal/disposal of the batteries?

Offline Jim

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Re: General Falcon and Dragon discussion (Thread 15)
« Reply #2 on: 10/12/2018 01:57 pm »
With the recent Soyuz mishap, an expected EVA at ISS to install batteries delivered by HTV may not happen soon. If the old batteries can't be placed in the HTV battery carrier before it leaves prior to the next cargo Dragon, can the HTV battery carrier be removed and stored, then installed ad hoc in cargo Dragon's trunk for removal/disposal of the batteries?

no.

Offline whitelancer64

Re: General Falcon and Dragon discussion (Thread 15)
« Reply #3 on: 10/12/2018 02:20 pm »
https://spacenews.com/safety-panel-fears-soyuz-failure-could-exacerbate-commercial-crew-safety-concerns/

Quote
concerns about issues with the Dragon’s parachute system, citing anomalies during testing of the Crew Dragon spacecraft and unspecified problems with cargo versions of the Dragon.

Does anyone know what anomalies / problems there have been?
"One bit of advice: it is important to view knowledge as sort of a semantic tree -- make sure you understand the fundamental principles, ie the trunk and big branches, before you get into the leaves/details or there is nothing for them to hang on to." - Elon Musk
"There are lies, damned lies, and launch schedules." - Larry J

Online abaddon

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Re: General Falcon and Dragon discussion (Thread 15)
« Reply #4 on: 10/12/2018 02:31 pm »
https://spacenews.com/safety-panel-fears-soyuz-failure-could-exacerbate-commercial-crew-safety-concerns/

Quote
concerns about issues with the Dragon’s parachute system, citing anomalies during testing of the Crew Dragon spacecraft and unspecified problems with cargo versions of the Dragon.

Does anyone know what anomalies / problems there have been?

https://forum.nasaspaceflight.com/index.php?topic=35717.msg1866852#msg1866852

Offline HarryM

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Re: General Falcon and Dragon discussion (Thread 15)
« Reply #5 on: 10/12/2018 04:52 pm »
How many flights have the new COPV's had? Have they flown them yet?

Offline whitelancer64

Re: General Falcon and Dragon discussion (Thread 15)
« Reply #6 on: 10/12/2018 10:17 pm »
How many flights have the new COPV's had? Have they flown them yet?

As far as I know, core 51 - scheduled to fly the DM-1 mission - is the first time the COPV 2.0 will be flown.
"One bit of advice: it is important to view knowledge as sort of a semantic tree -- make sure you understand the fundamental principles, ie the trunk and big branches, before you get into the leaves/details or there is nothing for them to hang on to." - Elon Musk
"There are lies, damned lies, and launch schedules." - Larry J

Offline gongora

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Re: General Falcon and Dragon discussion (Thread 15)
« Reply #7 on: 10/12/2018 10:39 pm »
How many flights have the new COPV's had? Have they flown them yet?

As far as I know, core 51 - scheduled to fly the DM-1 mission - is the first time the COPV 2.0 will be flown.

Core 1051 was rumored to be the first with the new COPV design.  It's likely a core built after 1051 will fly before DM-1.

Offline lucas071200

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Re: General Falcon and Dragon discussion (Thread 15)
« Reply #8 on: 10/17/2018 05:03 pm »
Where are from the outside visible differences on a Falcon heavy center core and a normal booster core? Only on the interstage or anywhere else

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Offline docmordrid

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Re: General Falcon and Dragon discussion (Thread 15)
« Reply #9 on: 10/17/2018 11:05 pm »
Below the booster nose cones and between the 3 octawebs there are  longerons connecting the  boosters to the center core.
« Last Edit: 10/17/2018 11:12 pm by docmordrid »
DM

Offline gongora

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Re: General Falcon and Dragon discussion (Thread 15)
« Reply #10 on: 11/27/2018 02:14 pm »
These are from the draft environmental assessment for the in-flight abort test, it seems to have a different version of the previously seen environmental assessment for Dragon recovery.

The second table is about fairing parachute recovery.
« Last Edit: 11/27/2018 02:15 pm by gongora »

Offline Raul

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Re: General Falcon and Dragon discussion (Thread 15)
« Reply #11 on: 11/28/2018 12:08 pm »
Btw.. Dragon-1 Parachute Recovery more or less correspond to the positions of my map records.
But what does not correspond at all is CRS-4 Recovery - where the reported distance 235nm from Port would be completely outside issued hazard area between 261-605nm from Port.

Note also, that record of Payload Fairing Recovery approx.425nm from Shore is really very rough.
SES-10 and BulgariaSat-1 missions are ok, but...
Intelsat-35e fairing recovery as expendable flight should be even theoretically a bit further than GTO missions with ASDS booster recovery - 488nm according to fairing boot MarineTrafic position
NROL-76 has to be wrong, because it had hazard area only until 245nm downrange - LEO mission with RTLS booster landing.

Offline gongora

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Re: General Falcon and Dragon discussion (Thread 15)
« Reply #12 on: 11/28/2018 02:28 pm »
Btw.. Dragon-1 Parachute Recovery more or less correspond to the positions of my map records.
But what does not correspond at all is CRS-4 Recovery - where the reported distance 235nm from Port would be completely outside issued hazard area between 261-605nm from Port.

Note also, that record of Payload Fairing Recovery approx.425nm from Shore is really very rough.
SES-10 and BulgariaSat-1 missions are ok, but...
Intelsat-35e fairing recovery as expendable flight should be even theoretically a bit further than GTO missions with ASDS booster recovery - 488nm according to fairing boot MarineTrafic position
NROL-76 has to be wrong, because it had hazard area only until 245nm downrange - LEO mission with RTLS booster landing.

That appears to be a draft version of the earlier EA, so I'd bet there is some incorrect information (even the information in the final EA reports usually has some errors.)

Offline gongora

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Re: General Falcon and Dragon discussion (Thread 15)
« Reply #13 on: 12/02/2018 11:34 pm »
SpaceX now has their NOAA license for the cameras on Dragon.

Offline docmordrid

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Re: General Falcon and Dragon discussion (Thread 15)
« Reply #14 on: 12/04/2018 10:01 am »
Oopsie...

Eric Berger ✔ @SciGuySpace (Ars)
I've had lots of questions about the fate of the Europa mission after Rep. Culberson lost his seat. Here, finally, are some answers.
Ars story...
>
Will the Europa missions be iced after congressmans defeat? Not right now
|
Fans of @SpaceX will be interested to note that the government is now taking very seriously the possibility of flying Clipper on the Falcon Heavy.
9:01 AM - Dec 3, 2018

https://twitter.com/SciGuySpace/status/1069592573604433920
« Last Edit: 12/04/2018 10:04 am by docmordrid »
DM

Offline MATTBLAK

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Re: General Falcon and Dragon discussion (Thread 15)
« Reply #15 on: 12/04/2018 10:05 am »
And to think; when I suggested this very thing on one or two NSF threads; some people got very huffy about it... ;)
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Offline docmordrid

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Re: General Falcon and Dragon discussion (Thread 15)
« Reply #16 on: 12/04/2018 10:40 am »
Sen. Shelby is going to need a bigger fire hose to put out all these grass fires.

From the Ars article

Quote
The breakthrough referenced by Goldstein involved the addition of a Star 48 "kick stage" to the Falcon Heavy rocket, which would provide an extra boost of energy after the rocket's upper stage had fired. With this solid rocket motor kick stage, Goldstein said Clipper would need just a single Earth gravity assist and would not have to go into the inner Solar System for a Venus flyby.

"Nobody is saying we're not going on the SLS," Goldstein said. "But if by chance we don't, we don't have the challenge of the inner Solar System. This was a major development. This was a big deal for us."

Offline MATTBLAK

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Re: General Falcon and Dragon discussion (Thread 15)
« Reply #17 on: 12/04/2018 10:44 am »
Sen. Shelby is going to need a bigger fire hose to put out all these grass fires.

From the Ars article

Quote
The breakthrough referenced by Goldstein involved the addition of a Star 48 "kick stage" to the Falcon Heavy rocket, which would provide an extra boost of energy after the rocket's upper stage had fired. With this solid rocket motor kick stage, Goldstein said Clipper would need just a single Earth gravity assist and would not have to go into the inner Solar System for a Venus flyby.

"Nobody is saying we're not going on the SLS," Goldstein said. "But if by chance we don't, we don't have the challenge of the inner Solar System. This was a major development. This was a big deal for us."
Eureka!!
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Online LouScheffer

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Re: General Falcon and Dragon discussion (Thread 15)
« Reply #18 on: 12/04/2018 12:54 pm »
From the Ars article

Quote
The breakthrough referenced by Goldstein involved the addition of a Star 48 "kick stage" to the Falcon Heavy rocket, which would provide an extra boost of energy after the rocket's upper stage had fired. With this solid rocket motor kick stage, Goldstein said Clipper would need just a single Earth gravity assist and would not have to go into the inner Solar System for a Venus flyby.

"Nobody is saying we're not going on the SLS," Goldstein said. "But if by chance we don't, we don't have the challenge of the inner Solar System. This was a major development. This was a big deal for us."

A Star-48 only adds a tiny bit of performance, so a Falcon Heavy alone could almost do the job.

A Star 48 has about 2114 kg mass, about 114 kg when done.  So assuming Clipper is 6 tonnes, as quoted, then at an ISP of 287, the Star-48 supplies 287*9.8*ln(8/6) = 809 m/s.

But the second stage performance is reduced by needing to boost the extra mass of the Star.  Assume that with no Star-48, the stack starts at 117t and ends at 11t.  But with the Star, it starts at 119t and ends at 13t.  At an ISP of 348, the extra mass then loses 348*9.8*(ln(117/11) - ln(119/13)) = 511 m/s.    So the net gain is only 809-511 = 298 m/s.

This is a pretty small faction of the 8000 m/s or so the second stage provides.  It's on the order of what a burn-to-depletion could provide, as opposed to a controlled shutdown.    But of course with a zillion dollar probe, they want to be sure they have the performance they need, not that it's merely likely.

Offline woods170

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Re: General Falcon and Dragon discussion (Thread 15)
« Reply #19 on: 12/04/2018 01:52 pm »
From the Ars article

Quote
The breakthrough referenced by Goldstein involved the addition of a Star 48 "kick stage" to the Falcon Heavy rocket, which would provide an extra boost of energy after the rocket's upper stage had fired. With this solid rocket motor kick stage, Goldstein said Clipper would need just a single Earth gravity assist and would not have to go into the inner Solar System for a Venus flyby.

"Nobody is saying we're not going on the SLS," Goldstein said. "But if by chance we don't, we don't have the challenge of the inner Solar System. This was a major development. This was a big deal for us."

A Star-48 only adds a tiny bit of performance, so a Falcon Heavy alone could almost do the job.

A Star 48 has about 2114 kg mass, about 114 kg when done.  So assuming Clipper is 6 tonnes, as quoted, then at an ISP of 287, the Star-48 supplies 287*9.8*ln(8/6) = 809 m/s.

But the second stage performance is reduced by needing to boost the extra mass of the Star.  Assume that with no Star-48, the stack starts at 117t and ends at 11t.  But with the Star, it starts at 119t and ends at 13t.  At an ISP of 348, the extra mass then loses 348*9.8*(ln(117/11) - ln(119/13)) = 511 m/s.    So the net gain is only 809-511 = 298 m/s.

This is a pretty small faction of the 8000 m/s or so the second stage provides.  It's on the order of what a burn-to-depletion could provide, as opposed to a controlled shutdown.    But of course with a zillion dollar probe, they want to be sure they have the performance they need, not that it's merely likely.

It'll use the STAR-48BV variant which has an ISP of 292 (not 287), has a mass of 2164 kg when loaded and a mass of 138 kg when done (See the numbers for STAR-48BV in the NGIS Motor Catalog from June 2018).

So, the STAR-48BV will kick in a little more delta-V than you calculated.
Also, I suggest you try to refine your assumptions for FH stage 2 performance numbers a bit.
« Last Edit: 12/04/2018 01:55 pm by woods170 »

Online abaddon

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Re: General Falcon and Dragon discussion (Thread 15)
« Reply #20 on: 12/04/2018 02:06 pm »
I'm a little baffled why this is called a "breakthrough".  Surely the idea of a kick motor for the Heavy was as obvious to these professionals as it was to many of us arm-chair observers who have mused about this for some time now?

Maybe the breakthrough was: being able to even consider the Heavy due to Class C certification that came through recently?  Or maybe the STAR-48BV that @woods170 mentions?
« Last Edit: 12/04/2018 02:07 pm by abaddon »

Online LouScheffer

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Re: General Falcon and Dragon discussion (Thread 15)
« Reply #21 on: 12/04/2018 02:41 pm »
A Star-48 only adds a tiny bit of performance, so a Falcon Heavy alone could almost do the job.

A Star 48 has about 2114 kg mass, about 114 kg when done.  So assuming Clipper is 6 tonnes, as quoted, then at an ISP of 287, the Star-48 supplies 287*9.8*ln(8/6) = 809 m/s.

But the second stage performance is reduced by needing to boost the extra mass of the Star.  Assume that with no Star-48, the stack starts at 117t and ends at 11t.  But with the Star, it starts at 119t and ends at 13t.  At an ISP of 348, the extra mass then loses 348*9.8*(ln(117/11) - ln(119/13)) = 511 m/s.    So the net gain is only 809-511 = 298 m/s.

This is a pretty small faction of the 8000 m/s or so the second stage provides.  It's on the order of what a burn-to-depletion could provide, as opposed to a controlled shutdown.    But of course with a zillion dollar probe, they want to be sure they have the performance they need, not that it's merely likely.

It'll use the STAR-48BV variant which has an ISP of 292 (not 287), has a mass of 2164 kg when loaded and a mass of 138 kg when done (See the numbers for STAR-48BV in the NGIS Motor Catalog from June 2018).

So, the STAR-48BV will kick in a little more delta-V than you calculated.
Also, I suggest you try to refine your assumptions for FH stage 2 performance numbers a bit.
These changes, while sensible, make only trivial differences to the calculation.  For example, with a 6000 kg Clipper, the Star-48BV provides 292*9.8*l(8164/6138) = 816 m/s, just 8 m/s more than calculated above.

As far as stage 2 performance, thanks to the environmental impact statement for the abort test, page 2-6, we now know the second stage fuel load:
Quote
Stage 2 LOX: 168,100 pounds
Stage 2 RP-1: 65,000 pounds
That's 233,000 lb of propellant, or 106t.   So now the only unknown is the mass of the empty second stage + residuals.  I assumed 5t (4.5t empty + 500 kg residuals).   If we assume the second stage is lighter (4t for stage + residuals) then the benefit becomes slightly less ( 348*9.8*(l(116/10) - l(118/12)) = 563 m/s lost by second stage from increased payload).   If we assume the second stage is on the heavy end of estimates, at 6t for empty + residuals, then the loss is 348*9.8*(l(118/12) - l(120/14)) = 468 m/s.   

Basically, any plausable mass for the second stage yields the same results.  The Star adds about 800 m/s, but the extra payload on the second stage will eat at least half of that.  So the overall gain is small, <400 m/s or so.

Offline TorenAltair

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Re: General Falcon and Dragon discussion (Thread 15)
« Reply #22 on: 12/04/2018 02:57 pm »
Why do they no longer use larger kick stages like the STAR 62 or so? Should improve things a bit.

Offline hkultala

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Re: General Falcon and Dragon discussion (Thread 15)
« Reply #23 on: 12/04/2018 03:20 pm »
From the Ars article

Quote
The breakthrough referenced by Goldstein involved the addition of a Star 48 "kick stage" to the Falcon Heavy rocket, which would provide an extra boost of energy after the rocket's upper stage had fired. With this solid rocket motor kick stage, Goldstein said Clipper would need just a single Earth gravity assist and would not have to go into the inner Solar System for a Venus flyby.

"Nobody is saying we're not going on the SLS," Goldstein said. "But if by chance we don't, we don't have the challenge of the inner Solar System. This was a major development. This was a big deal for us."

A Star-48 only adds a tiny bit of performance, so a Falcon Heavy alone could almost do the job.

A Star 48 has about 2114 kg mass, about 114 kg when done.  So assuming Clipper is 6 tonnes, as quoted, then at an ISP of 287, the Star-48 supplies 287*9.8*ln(8/6) = 809 m/s.

But the second stage performance is reduced by needing to boost the extra mass of the Star.  Assume that with no Star-48, the stack starts at 117t and ends at 11t.  But with the Star, it starts at 119t and ends at 13t.  At an ISP of 348, the extra mass then loses 348*9.8*(ln(117/11) - ln(119/13)) = 511 m/s.    So the net gain is only 809-511 = 298 m/s.

This is a pretty small faction of the 8000 m/s or so the second stage provides.  It's on the order of what a burn-to-depletion could provide, as opposed to a controlled shutdown.    But of course with a zillion dollar probe, they want to be sure they have the performance they need, not that it's merely likely.

"Small fraction" of delta-v difference can mean HUGE difference in overall performance requirements, because of the logarithmics on the rocket equation.

One should NEVER compare "fractions" of delta-v. Always calculate the absolute difference, or the pythagoran difference.

« Last Edit: 12/04/2018 03:20 pm by hkultala »

Offline envy887

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Re: General Falcon and Dragon discussion (Thread 15)
« Reply #24 on: 12/04/2018 06:00 pm »
A Star-48 only adds a tiny bit of performance, so a Falcon Heavy alone could almost do the job.

A Star 48 has about 2114 kg mass, about 114 kg when done.  So assuming Clipper is 6 tonnes, as quoted, then at an ISP of 287, the Star-48 supplies 287*9.8*ln(8/6) = 809 m/s.

But the second stage performance is reduced by needing to boost the extra mass of the Star.  Assume that with no Star-48, the stack starts at 117t and ends at 11t.  But with the Star, it starts at 119t and ends at 13t.  At an ISP of 348, the extra mass then loses 348*9.8*(ln(117/11) - ln(119/13)) = 511 m/s.    So the net gain is only 809-511 = 298 m/s.

This is a pretty small faction of the 8000 m/s or so the second stage provides.  It's on the order of what a burn-to-depletion could provide, as opposed to a controlled shutdown.    But of course with a zillion dollar probe, they want to be sure they have the performance they need, not that it's merely likely.

It'll use the STAR-48BV variant which has an ISP of 292 (not 287), has a mass of 2164 kg when loaded and a mass of 138 kg when done (See the numbers for STAR-48BV in the NGIS Motor Catalog from June 2018).

So, the STAR-48BV will kick in a little more delta-V than you calculated.
Also, I suggest you try to refine your assumptions for FH stage 2 performance numbers a bit.
These changes, while sensible, make only trivial differences to the calculation.  For example, with a 6000 kg Clipper, the Star-48BV provides 292*9.8*l(8164/6138) = 816 m/s, just 8 m/s more than calculated above.

As far as stage 2 performance, thanks to the environmental impact statement for the abort test, page 2-6, we now know the second stage fuel load:
Quote
Stage 2 LOX: 168,100 pounds
Stage 2 RP-1: 65,000 pounds
That's 233,000 lb of propellant, or 106t.   So now the only unknown is the mass of the empty second stage + residuals.  I assumed 5t (4.5t empty + 500 kg residuals).   If we assume the second stage is lighter (4t for stage + residuals) then the benefit becomes slightly less ( 348*9.8*(l(116/10) - l(118/12)) = 563 m/s lost by second stage from increased payload).   If we assume the second stage is on the heavy end of estimates, at 6t for empty + residuals, then the loss is 348*9.8*(l(118/12) - l(120/14)) = 468 m/s.   

Basically, any plausable mass for the second stage yields the same results.  The Star adds about 800 m/s, but the extra payload on the second stage will eat at least half of that.  So the overall gain is small, <400 m/s or so.

How many kg of payload does it add to a c3 of 85?

Per LSP, FH can lift 8230 kg to a c3 of 30, and 1810 kg to a c3 of 85.
« Last Edit: 12/04/2018 06:07 pm by envy887 »

Offline Negan

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Re: General Falcon and Dragon discussion (Thread 15)
« Reply #25 on: 12/04/2018 06:22 pm »
On a totally other note, any estimates on what a Dragon 2 trunk costs?

Offline woods170

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Re: General Falcon and Dragon discussion (Thread 15)
« Reply #26 on: 12/04/2018 06:28 pm »
A Star-48 only adds a tiny bit of performance, so a Falcon Heavy alone could almost do the job.

A Star 48 has about 2114 kg mass, about 114 kg when done.  So assuming Clipper is 6 tonnes, as quoted, then at an ISP of 287, the Star-48 supplies 287*9.8*ln(8/6) = 809 m/s.

But the second stage performance is reduced by needing to boost the extra mass of the Star.  Assume that with no Star-48, the stack starts at 117t and ends at 11t.  But with the Star, it starts at 119t and ends at 13t.  At an ISP of 348, the extra mass then loses 348*9.8*(ln(117/11) - ln(119/13)) = 511 m/s.    So the net gain is only 809-511 = 298 m/s.

This is a pretty small faction of the 8000 m/s or so the second stage provides.  It's on the order of what a burn-to-depletion could provide, as opposed to a controlled shutdown.    But of course with a zillion dollar probe, they want to be sure they have the performance they need, not that it's merely likely.

It'll use the STAR-48BV variant which has an ISP of 292 (not 287), has a mass of 2164 kg when loaded and a mass of 138 kg when done (See the numbers for STAR-48BV in the NGIS Motor Catalog from June 2018).

So, the STAR-48BV will kick in a little more delta-V than you calculated.
Also, I suggest you try to refine your assumptions for FH stage 2 performance numbers a bit.
These changes, while sensible, make only trivial differences to the calculation.  For example, with a 6000 kg Clipper, the Star-48BV provides 292*9.8*l(8164/6138) = 816 m/s, just 8 m/s more than calculated above.

Yes, that's why I said "a little more".

Offline GreenShrike

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Re: General Falcon and Dragon discussion (Thread 15)
« Reply #27 on: 12/04/2018 06:34 pm »
Why do they no longer use larger kick stages like the STAR 62 or so? Should improve things a bit.

Lou's always fun -- he shows how to do the math. You don't even need a fancy calculator -- just copy/paste the equations into Google and you'll get the answer.  ;-)


From the NGIS catalog, a STAR 63D has an ISP of ~283s, a starting mass of ~3.5t and a burnout mass of ~230kg.

So with a 6000kg Clipper, the STAR 63D provides:

283*9.8*ln((6+3.5)/(6+0.23)) = 1170m/s

The second stage, on the other hand, loses:

348*9.8*(ln((111+6)/(5+6)) - ln((111+6+3.5)/(5+6+3.5))) = 840m/s

For a whopping net of 330m/s.

So you're looking at a <50m/s gain at a cost of a kick stage almost twice the size of a STAR 48 (and over half the mass of the payload)

Oh, and the STAR 63D doesn't provide thrust vector control (TVC) -- going from a STAR 48B to a 48BV adds 20-odd kilos, so if Clipper needs a kick with TVC, the benefit will be even lower.
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Offline woods170

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Re: General Falcon and Dragon discussion (Thread 15)
« Reply #28 on: 12/04/2018 06:41 pm »
Why do they no longer use larger kick stages like the STAR 62 or so? Should improve things a bit.

Lou's always fun -- he shows how to do the math. You don't even need a fancy calculator -- just copy/paste the equations into Google and you'll get the answer.  ;-)


From the NGIS catalog, a STAR 63D has an ISP of ~283s, a starting mass of ~3.5t and a burnout mass of ~230kg.

So with a 6000kg Clipper, the STAR 63D provides:

283*9.8*ln((6+3.5)/(6+0.23)) = 1170m/s

The second stage, on the other hand, loses:

348*9.8*(ln((111+6)/(5+6)) - ln((111+6+3.5)/(5+6+3.5))) = 840m/s

For a whopping net of 330m/s.

So you're looking at a <50m/s gain at a cost of a kick stage almost twice the size of a STAR 48 (and over half the mass of the payload)

Oh, and the STAR 63D doesn't provide thrust vector control (TVC) -- going from a STAR 48B to a 48BV adds 20-odd kilos, so if Clipper needs a kick with TVC, the benefit will be even lower.


This.
The reason for STAR-48BV is the TVC system. A regular STAR-48 is spin stabilized, which requires the payload to de-spin after separation.
Europa Clipper is not designed to be inserted into orbit by spin-stabilized kick-stage. So, hence the need for TVC on the kick-stage. And that pretty much is how they got to STAR-48BV.

Offline GreenShrike

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Re: General Falcon and Dragon discussion (Thread 15)
« Reply #29 on: 12/04/2018 07:14 pm »
How many kg of payload does it add to a c3 of 85?

Per LSP, FH can lift 8230 kg to a c3 of 30, and 1810 kg to a c3 of 85.

A STAR 48BV doesn't, AFAICT. **

Given:

Payload 1.81t
STAR 48BV ISP 292s
STAR 48BV Mi 2.169t
STAR 48BV Mf .138t

The STAR would provide:

292*9.8*ln((1.81+2.169)/(1.81+0.138)) = ~2043m/s

However, the second stage loses:

348*9.8*(ln((111+1.81)/(5+1.81)) - ln((111+1.81+2.169)/(5+6+2.169))) = ~2184m/s

So you're looking at negative returns.


--------

**Edit -- Should actually be:

348*9.8*(ln((111+1.81)/(5+1.81)) - ln((111+1.81+2.169)/(5+1.81+2.169))) = 878m/s

For a positive return of 2043 - 878 = 1165m/s.


So apparently there are disadvantages to just plugging numbers into Google. ;-)

Ironically, I put together a spreadsheet for the below calc, but didn't bother going back to verify the above. <sigh>

--------

OTOH, if you drop the kick stage to a STAR 37GV...

Payload 1.81t
STAR 37GV ISP 293s
STAR 37GV Mi 1.087t
STAR 37GV Mf 0.104t

293*9.8*ln((1.81+1.087)/(1.81+0.104)) = ~1190m/s
348*9.8*(ln((111+1.81)/(5+1.81)) - ln((111+1.81+1.087)/(5+1.81+1.087))) = ~472m/s
1190 - 472 = 718m/s

...you get a decent amount of excess delta-V, so this kick stage is viable.


Upping the payload to 2.75t (chosen after some playing with figures ;-) ) gets you a kick of:

293*9.8*ln((2.75+1.087)/(2.75+0.104)) = ~849m/s

while sapping from the S2 (as compared against the 1.81t reference payload):

348*9.8*(ln((111+1.81)/(5+1.81)) - ln((111+2.75+1.087)/(5+2.75+1.087))) = ~827m/s

849 - 827 = 22m/s

So... maybe something a little under an additional tonne of payload?
« Last Edit: 12/05/2018 03:29 pm by GreenShrike »
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Re: General Falcon and Dragon discussion (Thread 15)
« Reply #30 on: 12/04/2018 08:40 pm »
How many kg of payload does it add to a c3 of 85?

Per LSP, FH can lift 8230 kg to a c3 of 30, and 1810 kg to a c3 of 85.

A STAR 48BV doesn't, AFAICT.

Given:

Payload 1.81t
STAR 48BV ISP 292s
STAR 48BV Mi 2.169t
STAR 48BV Mf .138t

The STAR would provide:

292*9.8*ln((1.81+2.169)/(1.81+0.138)) = ~2043m/s

However, the second stage loses:

348*9.8*(ln((111+1.81)/(5+1.81)) - ln((111+1.81+2.169)/(5+6+2.169))) = ~2184m/s

So you're looking at negative returns.


Think there is an error in your math. Using Space Launch Reports estimates for the Falcon 9 stages[1]and Star 48 BV numbers above, I get a net positive effect of ~1 km/s for a 1.81 t payload (no throttle down on heavy, core stages stage nearly at the same time).

My work: https://docs.google.com/spreadsheets/d/1XOKLBwm_0IOSWe7KZtz-NOxOGpIVd0alH36YOX2T2zo/edit?usp=sharing

[1]http://www.spacelaunchreport.com/falcon9ft.html

As far as what that means in terms of kilograms to a C3. The total stack delta v without the kick stage at 1810 kg matches total stack delta v with the kick stage at about 3040 kg.

But I think Jupiter direct is more like a C3 of 80, not 85 (at least if you optimize launch timing for lower C3). Which according to the LSP performance query, Falcon Heavy can do 2195 kg to. That should mean about 3,340 kg with a Star 48 BV stage as that is about where stack delta v without the kick stage and 2195 kg of payload matches with it.
« Last Edit: 12/04/2018 09:22 pm by ncb1397 »

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Re: General Falcon and Dragon discussion (Thread 15)
« Reply #31 on: 12/04/2018 10:11 pm »
How many kg of payload does it add to a c3 of 85?

Per LSP, FH can lift 8230 kg to a c3 of 30, and 1810 kg to a c3 of 85.

A STAR 48BV doesn't, AFAICT.

Given:

Payload 1.81t
STAR 48BV ISP 292s
STAR 48BV Mi 2.169t
STAR 48BV Mf .138t

The STAR would provide:

292*9.8*ln((1.81+2.169)/(1.81+0.138)) = ~2043m/s

However, the second stage loses:

348*9.8*(ln((111+1.81)/(5+1.81)) - ln((111+1.81+2.169)/(5+6+2.169))) = ~2184m/s

So you're looking at negative returns.


Think there is an error in your math.

I think the final 6 in that equation should be a 1.81 (perhaps confused the theoretical c3 of 85 payload with Europa Clipper's nominal mass), payload shouldn't lose mass while second stage is burning. That gives a loss of ~ 878 m/s for a net gain of  ~ 1165 m/s

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Re: General Falcon and Dragon discussion (Thread 15)
« Reply #32 on: 12/04/2018 11:14 pm »
It's not obvious to me why they need the Star-48 at all, if they are doing an Earth flyby.  Suppose they use a Juno-like strategy - Earth launch, deep space maneuver (DSM), Earth flyby, Jupiter.  According to the Ames trajectory browser, for launches in the 2020s, this requires a C3 of slightly less than 30 km^2/sec^2, and a deep space maneuver of about 7-800 m/s.    Juno used a similar trajectory with C3 = 31 and dV (deep space) of 730 m/s.

Now suppose a direct to Jupiter mission masses 6000 kg.  With the EEJ trajectory, you'll need enough extra fuel so that after the DSM the mass is 6000 kg.  How much extra fuel is needed?  For ISP=312 (as Juno), an 800 m/s manuever takes a mass ratio of exp(800/(312*9.8)) = 1.30.  So Clipper would need to start the DSM at 6000*1.30 = 7800 kg, finish at 6000 kg, then coast to Jupiter.

From the NASA LSP launch charts, FH expendable can put 8000 kg to a C3 of 30 km^2/sec^2, so this should be feasible.   All Clipper should need is larger tanks and it's ready to go.

So I can't see where using the Star-48 near Earth makes any sense.  If Clipper has enough dV for a DSM, it's not needed.  If not, then the place where they need the extra dV is in deep space.   So maybe they add a 2000 kg Star to a 6000 kg Clipper, then launch on a EEJ trajectory with Falcon Heavy.  Then the Star-48 performs the Deep Space Maneuver a year or so later.  It's just about the right size (800 m/s), so surely the trajectory can be adjusted to allow this.

The main question would seem to be whether the Star-48 is qualified to fire when fairly cold and after a year in space.  It would also explain why this was not an obvious solution.

 

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Re: General Falcon and Dragon discussion (Thread 15)
« Reply #33 on: 12/05/2018 12:09 am »
This discussion has been fascinating - I even understand some of the math! But seriously; can I assume that all iterations of Europa Clipper launched on Falcon Heavy would need a fully expendable FH, even with 1x Earth flyby?
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Re: General Falcon and Dragon discussion (Thread 15)
« Reply #34 on: 12/05/2018 12:22 am »
Why do they no longer use larger kick stages like the STAR 62 or so? Should improve things a bit.

Lou's always fun -- he shows how to do the math. You don't even need a fancy calculator -- just copy/paste the equations into Google and you'll get the answer.  ;-)


From the NGIS catalog, a STAR 63D has an ISP of ~283s, a starting mass of ~3.5t and a burnout mass of ~230kg.

So with a 6000kg Clipper, the STAR 63D provides:

283*9.8*ln((6+3.5)/(6+0.23)) = 1170m/s

The second stage, on the other hand, loses:

348*9.8*(ln((111+6)/(5+6)) - ln((111+6+3.5)/(5+6+3.5))) = 840m/s

For a whopping net of 330m/s.

So you're looking at a <50m/s gain at a cost of a kick stage almost twice the size of a STAR 48 (and over half the mass of the payload)

Oh, and the STAR 63D doesn't provide thrust vector control (TVC) -- going from a STAR 48B to a 48BV adds 20-odd kilos, so if Clipper needs a kick with TVC, the benefit will be even lower.


This.
The reason for STAR-48BV is the TVC system. A regular STAR-48 is spin stabilized, which requires the payload to de-spin after separation.
Europa Clipper is not designed to be inserted into orbit by spin-stabilized kick-stage. So, hence the need for TVC on the kick-stage. And that pretty much is how they got to STAR-48BV.
There's a version of STAR-63 that has TVC. It has been tested (on the ground, at least).
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Re: General Falcon and Dragon discussion (Thread 15)
« Reply #35 on: 12/05/2018 02:09 am »
This discussion has been fascinating - I even understand some of the math! But seriously; can I assume that all iterations of Europa Clipper launched on Falcon Heavy would need a fully expendable FH, even with 1x Earth flyby?
Yes, you need an expendable FH to get the performance needed.   From the NASA plot, FH recoverable (and I'm pretty sure this is still expending the center core, just recovering the two sides) can push 6000 kg to a C3 of about 5.  But for ANY trajectory to Jupiter, you need a C3 of at least 6-7 (since you need to reach some other planet to do a fly by, and Venus is the closest at C3 of 6-7 km^2/sec^2).   So not only can a FH recoverable not do the Earth-flyby trajectory, it can't do ANY trajectory to Jupiter with a 6000 kg payload.

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Re: General Falcon and Dragon discussion (Thread 15)
« Reply #36 on: 12/05/2018 12:00 pm »
ncb, you are assuming a 1.81 mT payload vs. Lou is using a 6mT payload. Which one is it?

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Re: General Falcon and Dragon discussion (Thread 15)
« Reply #37 on: 12/05/2018 12:36 pm »
ncb, you are assuming a 1.81 mT payload vs. Lou is using a 6mT payload. Which one is it?
From this JPL newsletter, the absolute maximum mass is 6001 kg.  A few hundred kg are being held in the project manager's reserve to solve unforseen issues.  So 5.8-6t will be the loaded launch mass.

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Re: General Falcon and Dragon discussion (Thread 15)
« Reply #38 on: 12/05/2018 02:07 pm »
A SPACEX DELIVERY CAPSULE MAY BE CONTAMINATING THE ISS

SARAH SCOLES SCIENCE 12.05.1807:00 AM

IN FEBRUARY 2017, a SpaceX Falcon 9 rocket lifted through low clouds, pushing a Dragon capsule toward orbit. Among the spare parts and food, an important piece of scientific cargo, called SAGE III, rumbled upward. Once installed on the International Space Station, SAGE would peer back and measure ozone molecules and aerosols in Earth’s atmosphere. Its older siblings (SAGEs I and II) had revealed both the growth of the gaping ozone hole and, after humans decided to stop spraying Freon everywhere, its subsequent recovery.

This third kid, then, had a lot to live up to. Like its environmentally conscious predecessors, SAGE III is super sensitive. Because it needs unpolluted conditions to operate optimally, it includes contamination sensors that keep an eye on whether and how its environment might be messing up its measurements. Those sensors soon came in handy: When the next three Dragons docked at the Space Station, over the following months, SAGE experienced unexplained spikes in contamination. Something on these Dragons was outgassing—releasing molecules beyond the expected, and perhaps the acceptable, levels. And those molecules were sticking to SAGE.

Outgassing, in earthly terms, is what makes a new car smell like a new car. “There are volatile chemicals in those new materials that migrate through the material to the surface," says Alan Tribble, author of Fundamentals of Contamination Control. You’re smelling escaped seat ingredients, in other words.

Outgassing also builds up as a greasy film on the inside of your new car’s windows—or the outside of your space station. This grime is mostly a problem for instruments that measure light, but it can also reduce solar panels’ efficiency and can make surfaces hotter than they’re supposed to be. To avoid all that, engineers build Space Station additions and satellites in clean rooms, use only prequalified materials, bake out contaminants before launch, and set strict limits on how much proverbial new-car smell a craft can release. “It’s an intense process and considered extremely critical,” says Meg Abraham of the Aerospace Corporation, which consults on a number of space projects. “Everyone thinks about this.”

https://www.wired.com/story/a-spacex-delivery-capsule-may-be-contaminating-the-iss/

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Re: General Falcon and Dragon discussion (Thread 15)
« Reply #39 on: 12/05/2018 02:23 pm »
To bad the story about out-gassing on the Dragon hadn't been known a couple of days earlier.  Would like to have seen the response to questions on this from NASA and SpaceX at the CRS-16 press conference. 
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Re: General Falcon and Dragon discussion (Thread 15)
« Reply #40 on: 12/05/2018 02:25 pm »
To bad the story about out-gassing on the Dragon hadn't been known a couple of days earlier.  Would like to have seen the response to questions on this from NASA and SpaceX at the CRS-16 press conference.

There's always the post-launch press conference ...

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Re: General Falcon and Dragon discussion (Thread 15)
« Reply #41 on: 12/05/2018 02:38 pm »
To bad the story about out-gassing on the Dragon hadn't been known a couple of days earlier.  Would like to have seen the response to questions on this from NASA and SpaceX at the CRS-16 press conference.

It's been known for a while, there are probably previous posts somewhere on the site.

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Re: General Falcon and Dragon discussion (Thread 15)
« Reply #42 on: 12/05/2018 02:42 pm »
To bad the story about out-gassing on the Dragon hadn't been known a couple of days earlier.  Would like to have seen the response to questions on this from NASA and SpaceX at the CRS-16 press conference.

It's been known for a while, there are probably previous posts somewhere on the site.

This is in the article:
Quote
After the eleventh Dragon arrived, one contamination-monitoring package’s frequency steadily shifted, according to a presentation posted on September 1 to NASA’s Technical Reports Server, a database of documents created or funded by the agency.

The article has a link to this presentation from September.
https://www.spiedigitallibrary.org/conference-proceedings-of-spie/10748/1074805/Analysis-of-observed-contamination-through-SAGE-IIIs-first-year-on/10.1117/12.2321982.short?SSO=1

Offline GreenShrike

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Re: General Falcon and Dragon discussion (Thread 15)
« Reply #43 on: 12/05/2018 04:16 pm »
ncb, you are assuming a 1.81 mT payload vs. Lou is using a 6mT payload. Which one is it?

I understood that the 1.81t was what FH could send directly to Jupiter via NASA's C3=85 figures, and he wanted to know if a kick stage could boost that payload up to Clipper's mass of 6t.

I think the final 6 in that equation should be a 1.81 (perhaps confused the theoretical c3 of 85 payload with Europa Clipper's nominal mass), payload shouldn't lose mass while second stage is burning. That gives a loss of ~ 878 m/s for a net gain of  ~ 1165 m/s

Yes, exactly -- I reused the equations I'd entered into Google and forgot to mod one of the values from previous. I've edited my post to reflect the update.

To re-answer ncb's question, with a C3=85 payload of 1.81t, adding a STAR 48 should increase payload to around 3.25t.

But I think Jupiter direct is more like a C3 of 80, not 85 (at least if you optimize launch timing for lower C3). Which according to the LSP performance query, Falcon Heavy can do 2195 kg to. That should mean about 3,340 kg with a Star 48 BV stage as that is about where stack delta v without the kick stage and 2195 kg of payload matches with it.

With a 2.195t reference payload, I make a STAR 48BV increasing payload to around 3.5t. I'm guessing the difference is your sub-optimal handing of FH's booster staging (i.e. not throttling FH's center core).

I also get ~3.75t with a STAR 63D -- probably a little less once a TVC is added.

Here's my work:

https://docs.google.com/spreadsheets/d/1wayCq0sx2_lAumbvVD-5iWEun57z7aVSZlulvWH26lw/edit?usp=sharing
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Offline woods170

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Re: General Falcon and Dragon discussion (Thread 15)
« Reply #44 on: 12/06/2018 09:37 am »
To bad the story about out-gassing on the Dragon hadn't been known a couple of days earlier.  Would like to have seen the response to questions on this from NASA and SpaceX at the CRS-16 press conference.

It's been known for a while, there are probably previous posts somewhere on the site.

This is in the article:
Quote
After the eleventh Dragon arrived, one contamination-monitoring package’s frequency steadily shifted, according to a presentation posted on September 1 to NASA’s Technical Reports Server, a database of documents created or funded by the agency.

The article has a link to this presentation from September.
https://www.spiedigitallibrary.org/conference-proceedings-of-spie/10748/1074805/Analysis-of-observed-contamination-through-SAGE-IIIs-first-year-on/10.1117/12.2321982.short?SSO=1

Also noted in the article:

Quote from: Sarah Scoles
SpaceX, meanwhile, is looking at its ingredients. “SpaceX has scrutinized all external material selections on Dragon and is working with suppliers to custom-develop low outgassing variants of qualified materials to help improve the molecular deposition rate,” says the company, adding that NASA pre-approved all the materials used in the first Dragon design.

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Re: General Falcon and Dragon discussion (Thread 15)
« Reply #45 on: 12/06/2018 10:09 am »
Also noted in the article:

Quote from: Sarah Scoles
SpaceX, meanwhile, is looking at its ingredients. “SpaceX has scrutinized all external material selections on Dragon and is working with suppliers to custom-develop low outgassing variants of qualified materials to help improve the molecular deposition rate,” says the company, adding that NASA pre-approved all the materials used in the first Dragon design.

Not only that, but the whole article is odd. From the headline you'd think SpaceX was gassing crew members. This feels like someone taking some random safety study from Crew Dragon and claiming "Commercial crew is killing our astronauts!". It's a known issue that is being worked on by NASA, just like about a hundred other small things on the space station. It's not better or worse than other things that are happening and there's no reason to be suddenly very concerned.
Which booster has the most soot? SpaceX booster launch history! (discussion)

Offline programmerdan

Re: General Falcon and Dragon discussion (Thread 15)
« Reply #46 on: 12/06/2018 01:18 pm »
Also noted in the article:

Quote from: Sarah Scoles
SpaceX, meanwhile, is looking at its ingredients. “SpaceX has scrutinized all external material selections on Dragon and is working with suppliers to custom-develop low outgassing variants of qualified materials to help improve the molecular deposition rate,” says the company, adding that NASA pre-approved all the materials used in the first Dragon design.

Not only that, but the whole article is odd. From the headline you'd think SpaceX was gassing crew members. This feels like someone taking some random safety study from Crew Dragon and claiming "Commercial crew is killing our astronauts!". It's a known issue that is being worked on by NASA, just like about a hundred other small things on the space station. It's not better or worse than other things that are happening and there's no reason to be suddenly very concerned.

The conspiratorial vibe that "We asked questions and NASA pulled the report!!!!" was also not a welcome facet of the article.

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Re: General Falcon and Dragon discussion (Thread 15)
« Reply #47 on: 12/06/2018 10:53 pm »
Not only that, but the whole article is odd. From the headline you'd think SpaceX was gassing crew members. This feels like someone taking some random safety study from Crew Dragon and claiming "Commercial crew is killing our astronauts!". It's a known issue that is being worked on by NASA, just like about a hundred other small things on the space station. It's not better or worse than other things that are happening and there's no reason to be suddenly very concerned.
.

Outgassing waste deposition of tens of times the allowable limits for the world-class scientific instruments the Station is supposed and mandated to host is no small issue, IMO.
The numbers of how many FOIA requests were denied by NASA and the immediate conclusions the author draws from it aren't negligible either.
-DaviD-

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Re: General Falcon and Dragon discussion (Thread 15)
« Reply #48 on: 12/07/2018 06:48 am »
Not only that, but the whole article is odd. From the headline you'd think SpaceX was gassing crew members. This feels like someone taking some random safety study from Crew Dragon and claiming "Commercial crew is killing our astronauts!". It's a known issue that is being worked on by NASA, just like about a hundred other small things on the space station. It's not better or worse than other things that are happening and there's no reason to be suddenly very concerned.
.

Outgassing waste deposition of tens of times the allowable limits for the world-class scientific instruments the Station is supposed and mandated to host is no small issue, IMO.
The numbers of how many FOIA requests were denied by NASA and the immediate conclusions the author draws from it aren't negligible either.

Anybody with knowledge on the subject can tell you that placing world-class scientific instruments on a station, that is regularly being visited by manned and un-manned vehicles, is not the optimal thing to do. NASA found this out early in the shuttle program when some of the instruments flying on Spacelab missions suffered badly from outgassing effects, as well as deposits from RCS bursts.

Why do you think both NASA and ESA originally proposed to have free-flyer platforms, associated with the space station?

They were intented for hosting contamination-sensitive payloads and instrument.

However, the free-flyer platforms fell to the budget axe. So NASA and ESA ended up putting the instruments directly on the ISS structure. That necessitated minimizing outgassing from ISS structures, as well as non-propulsive attitude control of the ISS.

But make no mistake; every time the ISS is visited by a vehicle (be it Shuttle, HTV, Soyuz, Progress, Cygnus or Dragon) the station gets shrouded in a blanket of RCS by-products and outgassing products from said vehicles.
Its not just Dragon polluting the ISS environment. The other craft have that effect too.

Offline eeergo

Re: General Falcon and Dragon discussion (Thread 15)
« Reply #49 on: 12/07/2018 07:13 am »
Sure, I am aware about free-flyers, and there's no question about them being preferable from a disturbances (contamination and other types) point of view. But we're talking order-of-magnitude effects here, not optimal-yet-unrealizable (in the near term, with current platforms) architectures.

Do other VVs regularly pollute sensitive instruments almost 2 orders of magnitude over nominal limits during docked ops?

If so, why is this issue raised as an anomaly for Dragon, and why are the limits so conservative or the mitigation measures so lacking?

If not, what does Dragon do wrong (from the article: paint?), what long-term effects will it have on instruments sensitive to such outgassing if allowed to go on, should the limits be relaxed for certain compounds, should ...?

These issues, if as described in the article (and it appears well-referenced, so no reason to doubt it too much) are hardly like "a hundred other small things" or "not better or worse than any other thing happening", whatever that may mean, as described a few comments above.
-DaviD-

Offline SWGlassPit

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Re: General Falcon and Dragon discussion (Thread 15)
« Reply #50 on: 12/07/2018 03:18 pm »
Also noted in the article:

Quote from: Sarah Scoles
SpaceX, meanwhile, is looking at its ingredients. “SpaceX has scrutinized all external material selections on Dragon and is working with suppliers to custom-develop low outgassing variants of qualified materials to help improve the molecular deposition rate,” says the company, adding that NASA pre-approved all the materials used in the first Dragon design.

Not only that, but the whole article is odd. From the headline you'd think SpaceX was gassing crew members. This feels like someone taking some random safety study from Crew Dragon and claiming "Commercial crew is killing our astronauts!". It's a known issue that is being worked on by NASA, just like about a hundred other small things on the space station. It's not better or worse than other things that are happening and there's no reason to be suddenly very concerned.

The conspiratorial vibe that "We asked questions and NASA pulled the report!!!!" was also not a welcome facet of the article.

Welcome or not, it happened.  It's not even on the non-public NTRS anymore.

Online Alexphysics

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Re: General Falcon and Dragon discussion (Thread 15)
« Reply #51 on: 12/07/2018 05:28 pm »
Not only that, but the whole article is odd. From the headline you'd think SpaceX was gassing crew members. This feels like someone taking some random safety study from Crew Dragon and claiming "Commercial crew is killing our astronauts!". It's a known issue that is being worked on by NASA, just like about a hundred other small things on the space station. It's not better or worse than other things that are happening and there's no reason to be suddenly very concerned.
.

Outgassing waste deposition of tens of times the allowable limits for the world-class scientific instruments the Station is supposed and mandated to host is no small issue, IMO.
The numbers of how many FOIA requests were denied by NASA and the immediate conclusions the author draws from it aren't negligible either.

Anybody with knowledge on the subject can tell you that placing world-class scientific instruments on a station, that is regularly being visited by manned and un-manned vehicles, is not the optimal thing to do. NASA found this out early in the shuttle program when some of the instruments flying on Spacelab missions suffered badly from outgassing effects, as well as deposits from RCS bursts.

Why do you think both NASA and ESA originally proposed to have free-flyer platforms, associated with the space station?

They were intented for hosting contamination-sensitive payloads and instrument.

However, the free-flyer platforms fell to the budget axe. So NASA and ESA ended up putting the instruments directly on the ISS structure. That necessitated minimizing outgassing from ISS structures, as well as non-propulsive attitude control of the ISS.

But make no mistake; every time the ISS is visited by a vehicle (be it Shuttle, HTV, Soyuz, Progress, Cygnus or Dragon) the station gets shrouded in a blanket of RCS by-products and outgassing products from said vehicles.
Its not just Dragon polluting the ISS environment. The other craft have that effect too.

Although I'm with you on the first part and it's true that Soyuz and the rest of the other vehicles create some of the contamination, Dragon is by far the one that contaminates the most with high rates right at the times when a Dragon is on station while when other vehicles go and stay there the contamination rises only a bit. However... it's true this is not a big issue and can be corrected so that Dragon stays on the same levels as the other vehicles, this is totally normal to happen in this industry, there are always unknowns even when more than 10 dragons have flown into space and back, we just have to wait and see what they do and what can be done, I'm confident they'll get it right :)

Offline programmerdan

Re: General Falcon and Dragon discussion (Thread 15)
« Reply #52 on: 12/07/2018 05:33 pm »
Also noted in the article:

Quote from: Sarah Scoles
SpaceX, meanwhile, is looking at its ingredients. “SpaceX has scrutinized all external material selections on Dragon and is working with suppliers to custom-develop low outgassing variants of qualified materials to help improve the molecular deposition rate,” says the company, adding that NASA pre-approved all the materials used in the first Dragon design.

Not only that, but the whole article is odd. From the headline you'd think SpaceX was gassing crew members. This feels like someone taking some random safety study from Crew Dragon and claiming "Commercial crew is killing our astronauts!". It's a known issue that is being worked on by NASA, just like about a hundred other small things on the space station. It's not better or worse than other things that are happening and there's no reason to be suddenly very concerned.

The conspiratorial vibe that "We asked questions and NASA pulled the report!!!!" was also not a welcome facet of the article.

Welcome or not, it happened.  It's not even on the non-public NTRS anymore.

It appears to still be here: https://www.spiedigitallibrary.org/conference-proceedings-of-spie/10748/1074805/Analysis-of-observed-contamination-through-SAGE-IIIs-first-year-on/10.1117/12.2321982.short?SSO=1

The paywall sucks, but probably could just email the principles for a copy. Horrible optics for NASA to pull it, totally agree.

Offline ncb1397

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Re: General Falcon and Dragon discussion (Thread 15)
« Reply #53 on: 12/07/2018 06:35 pm »

If not, what does Dragon do wrong (from the article: paint?), what long-term effects will it have on instruments sensitive to such outgassing if allowed to go on, should the limits be relaxed for certain compounds, should ...?

My guess is they aren't properly baking everything out.

This video goes into how it is done for Mars 2020:


From what I can tell from the graph posted above, there is a spike after docking but it flattens out in the period prior to release. This suggests it is simply a matter of duration of simulating the space environment on the ground during the baking process prior to launch to reduce the affect substantially. This is assuming contaminants aren't re-absorbed in the launch process afterwards though.
« Last Edit: 12/07/2018 07:13 pm by ncb1397 »

Offline Wolfram66

Re: General Falcon and Dragon discussion (Thread 15)
« Reply #54 on: 12/07/2018 10:04 pm »
Quote
Although I'm with you on the first part and it's true that Soyuz and the rest of the other vehicles create some of the contamination, Dragon is by far the one that contaminates the most with high rates right at the times when a Dragon is on station while when other vehicles go and stay there the contamination rises only a bit. However... it's true this is not a big issue and can be corrected so that Dragon stays on the same levels as the other vehicles, this is totally normal to happen in this industry, there are always unknowns even when more than 10 dragons have flown into space and back, we just have to wait and see what they do and what can be done, I'm confident they'll get it right :)

One question is there a difference between a New Dragon and a recently refurbished Dragon? Are the procedures to re-paint, re-PICA-X and re-SPAM not baking out the VOC's effectively or does the heat of re-entry affect the process. someone will need to pull which the offending Dragons and correlate..

EDIT: https://en.wikipedia.org/wiki/SpaceX_Dragon

The following are CRS missions using Re-flown Dragons
CRS-11
CRS-13
CRS-14
CRS-15
CRS-16
« Last Edit: 12/07/2018 10:08 pm by Wolfram66 »

Offline deruch

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Re: General Falcon and Dragon discussion (Thread 15)
« Reply #55 on: 12/08/2018 10:19 pm »
Quote
Although I'm with you on the first part and it's true that Soyuz and the rest of the other vehicles create some of the contamination, Dragon is by far the one that contaminates the most with high rates right at the times when a Dragon is on station while when other vehicles go and stay there the contamination rises only a bit. However... it's true this is not a big issue and can be corrected so that Dragon stays on the same levels as the other vehicles, this is totally normal to happen in this industry, there are always unknowns even when more than 10 dragons have flown into space and back, we just have to wait and see what they do and what can be done, I'm confident they'll get it right :)

One question is there a difference between a New Dragon and a recently refurbished Dragon? Are the procedures to re-paint, re-PICA-X and re-SPAM not baking out the VOC's effectively or does the heat of re-entry affect the process. someone will need to pull which the offending Dragons and correlate..

EDIT: https://en.wikipedia.org/wiki/SpaceX_Dragon

The following are CRS missions using Re-flown Dragons
CRS-11
CRS-13
CRS-14
CRS-15
CRS-16

The original Wired article, paraphrasing the SAGE III presentation, said that CRS-11 showed 21x over the contamination limits and CRS-12 at 32x over.  So, it's clearly not an issue limited to only the first flights of Dragons.  I don't believe that the currently public information is sufficient to determine whether the difference in outgassing between "new" and "reflown" vehicles is statistically significant.
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Offline Comga

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Re: General Falcon and Dragon discussion (Thread 15)
« Reply #56 on: 12/08/2018 11:34 pm »
Statement:
I have direct knowledge of this instrument and measurements and am not throwing things against the wall to see what sticks.  This is within my professional wheelhouse.

I have access to and have downloaded the SPIE (Society for Optical Engineering) article which contains the technical discussion on which this discussion is based and from which the half-hidden graph was pulled.

There are quite large pulses of contamination in the ram direction (looking "forward" against the velocity and against the flow of the exosphere through which the ISS flies) for some, but not all, of the Dragon visits.  The first visit, which may have been CRS-11, was not accompanied by a clearly resolved spike in condensable volities.  The other two were.

Also contained in the article is a graph of the transmission on the SAGE-III contamination door/window at specific wavelengths including 290 nm, the UV wavelength of the high altitude Ozone measurements.  While there is a decrease of transmission of (edit: up to 2%), the transmission returns to the baseline in a few weeks.  This is quite transient deposition if the surface is not cooled like the TQCM contamination monitors.  The effect decreases as the wavelength increases, becoming minuscule beyond the visible spectrum. (SAGE-III has SWIR channels to 1050 nm plus one at 1550 nm.)  Given the way SAGE-III operates, it does not significantly degrade the Ozone measurements, or any others.  If this outgassed material deposits elsewhere on ISS hardware, it probably dissipates rapidly from there, too.

The measurements of SAGE-III-ISS on, of course, the ISS, can be contrasted to those of it's twin, SAGE-III-M3 which flew on the Russian meteorological satellite Meteor-3M.  My understanding, although I have not seen the data, is that it's UV channel was rendered useless by contamination within the first year of operations. Those who extol the virtue of free-fliers can take note.   

The comparisons to the Soyuz and Progress dockings are direct, but somewhat disingenuous.  Those craft approach and dock to the Russian "back half" segment of the ISS.  Emitted volitiles are swept away from the American "front half" segment.  SAGE-III-ISS is mounted close behind, and just off to the starboard side of the ISS, from where the Dragons are berthed, a great spot to collect emitted material from them.  The solar panels, which were hypothesized as being potentially contaminated, are far to the sides, so less likely to collect condensables, and likely to quickly shed them as they warm in the sunlight.     

As of this week there have been three more Dragons berthed to the ISS.  It would be very interesting to see the data from this doubling of the number of visits.
« Last Edit: 12/11/2018 05:06 am by Comga »
What kind of wastrels would dump a perfectly good booster in the ocean after just one use?

Offline niwax

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Re: General Falcon and Dragon discussion (Thread 15)
« Reply #57 on: 12/09/2018 12:31 am »
Quote
Although I'm with you on the first part and it's true that Soyuz and the rest of the other vehicles create some of the contamination, Dragon is by far the one that contaminates the most with high rates right at the times when a Dragon is on station while when other vehicles go and stay there the contamination rises only a bit. However... it's true this is not a big issue and can be corrected so that Dragon stays on the same levels as the other vehicles, this is totally normal to happen in this industry, there are always unknowns even when more than 10 dragons have flown into space and back, we just have to wait and see what they do and what can be done, I'm confident they'll get it right :)

One question is there a difference between a New Dragon and a recently refurbished Dragon? Are the procedures to re-paint, re-PICA-X and re-SPAM not baking out the VOC's effectively or does the heat of re-entry affect the process. someone will need to pull which the offending Dragons and correlate..

EDIT: https://en.wikipedia.org/wiki/SpaceX_Dragon

The following are CRS missions using Re-flown Dragons
CRS-11
CRS-13
CRS-14
CRS-15
CRS-16

The original Wired article, paraphrasing the SAGE III presentation, said that CRS-11 showed 21x over the contamination limits and CRS-12 at 32x over.  So, it's clearly not an issue limited to only the first flights of Dragons.  I don't believe that the currently public information is sufficient to determine whether the difference in outgassing between "new" and "reflown" vehicles is statistically significant.

I believe Dragon are largely rebuilt, they are being reused mainly to shut down pressure vessel production. The paint or even the entire outer hull is likely reapplied before every flight, so reuse should not make a difference.
Which booster has the most soot? SpaceX booster launch history! (discussion)

Offline Okie_Steve

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Re: General Falcon and Dragon discussion (Thread 15)
« Reply #58 on: 12/10/2018 04:55 am »
I remember Elon once commented that an F9 booster could more or less do SSTO just not with any payload. Using two stages made much more sense. So, my question is,  what could an F9 stack with no payload do? Would lunar free return be a possibility? That could make one heck of a TPS test.

Offline HMXHMX

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Re: General Falcon and Dragon discussion (Thread 15)
« Reply #59 on: 12/10/2018 10:58 pm »
I remember Elon once commented that an F9 booster could more or less do SSTO just not with any payload. Using two stages made much more sense. So, my question is,  what could an F9 stack with no payload do? Would lunar free return be a possibility? That could make one heck of a TPS test.

Heck, the Titan II first stage could do expendable SSTO, and with a 1400 lb. payload – it is just that the burnout Gs would be intolerable, given lack of throttle on the engines.  I'm pretty sure that a 0.96 PMF F9 S1 could provide a 40 or 50:1 growth factor (ratio of GLOW to PL) easily enough, and without the Titan II Gs problem, since F9 engines can be shut off in pairs, down to the central single one, which itself can slightly throttle as well.

It'd be amusing for someone to run OTIS or POST on such an option.
« Last Edit: 12/11/2018 04:18 am by HMXHMX »

Offline Lars-J

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Re: General Falcon and Dragon discussion (Thread 15)
« Reply #60 on: 12/11/2018 12:21 am »
I remember Elon once commented that an F9 booster could more or less do SSTO just not with any payload. Using two stages made much more sense. So, my question is,  what could an F9 stack with no payload do? Would lunar free return be a possibility? That could make one heck of a TPS test.

Heck, the Titan II first stage could do expendable SSTO, and with a 1400 lb. payload – it is just that the burnout Gs would be intolerable, given lack fo throttle on the engines.  I'm pretty sure that a 0.96 PMF F9 S1 could provide a 40 or 50:1 growth factor (ratio of GLOW to PL) easily enough, and without the Titan II Gs problem, since F9 engines can be shut off in pairs, down to the central single one, which itself can slightly throttle as well.

Surely throttling down to 40% of full thrust qualifies as more then just being able to "slightly throttle".  :) (Can't think of any booster engines capable of a greater throttle range other then perhaps RD-180)

Offline HMXHMX

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Re: General Falcon and Dragon discussion (Thread 15)
« Reply #61 on: 12/11/2018 12:31 am »
I remember Elon once commented that an F9 booster could more or less do SSTO just not with any payload. Using two stages made much more sense. So, my question is,  what could an F9 stack with no payload do? Would lunar free return be a possibility? That could make one heck of a TPS test.

Heck, the Titan II first stage could do expendable SSTO, and with a 1400 lb. payload – it is just that the burnout Gs would be intolerable, given lack fo throttle on the engines.  I'm pretty sure that a 0.96 PMF F9 S1 could provide a 40 or 50:1 growth factor (ratio of GLOW to PL) easily enough, and without the Titan II Gs problem, since F9 engines can be shut off in pairs, down to the central single one, which itself can slightly throttle as well.

Surely throttling down to 40% of full thrust qualifies as more then just being able to "slightly throttle".  :) (Can't think of any booster engines capable of a greater throttle range other then perhaps RD-180)

Glad of the correction; I thought Merlin 1D had a 70% minimum throttle limit. 

BTW, NK-33 demo’d ~30% on the Aerojet stand, as I recall, but that might be a false memory...

Offline Jim

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Re: General Falcon and Dragon discussion (Thread 15)
« Reply #62 on: 12/11/2018 12:50 am »
Sure, I am aware about free-flyers, and there's no question about them being preferable from a disturbances (contamination and other types) point of view. But we're talking order-of-magnitude effects here, not optimal-yet-unrealizable (in the near term, with current platforms) architectures.

Do other VVs regularly pollute sensitive instruments almost 2 orders of magnitude over nominal limits during docked ops?

If so, why is this issue raised as an anomaly for Dragon, and why are the limits so conservative or the mitigation measures so lacking?


Because they are non volatiles

Offline Comga

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Re: General Falcon and Dragon discussion (Thread 15)
« Reply #63 on: 12/11/2018 05:19 am »
Sure, I am aware about free-flyers, and there's no question about them being preferable from a disturbances (contamination and other types) point of view. But we're talking order-of-magnitude effects here, not optimal-yet-unrealizable (in the near term, with current platforms) architectures.

Do other VVs regularly pollute sensitive instruments almost 2 orders of magnitude over nominal limits during docked ops?

If so, why is this issue raised as an anomaly for Dragon, and why are the limits so conservative or the mitigation measures so lacking?

Because they are non volatiles

Using many more words than you do, I respectfully disagree.
They are, in fact, volatiles.
They persist on the cooled TQCMs but dissipate from the warm window of SAGE-III-ISS. 
That's why many optical windows have heaters.
They are unlikely to be RCS biproducts because complex hydrocarbons tend to solarize, polymerize in the harsh solar UV radiation, and accumulate for ever.  That's kind of stuff that will ruin instruments, particularly UV instruments.
The calculations of film thickness assume that the density of the condensibles is 1, like water.
In fact, water is a distinct possibility.  It could be absorbed by the SPAM on the Dragon while it's in the humid environment of the Cape and desorbed on orbit. 
Or it could be something that gets scrubbed by the atomic oxygen of LEO.
It could be much worse.  There are many examples, like the Stardust Navigation camera, that are.  (It was partially cleaned by accidentally pointing the camera at the Sun, but went from really clouded up to somewhat clouded up but usable for its Tempel 1 flyby.)

edit:  And Stardust was a "freeflyer", but had worse contamination, as did Meteor-3M, and others. 
« Last Edit: 12/11/2018 05:22 am by Comga »
What kind of wastrels would dump a perfectly good booster in the ocean after just one use?

Offline woods170

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Re: General Falcon and Dragon discussion (Thread 15)
« Reply #64 on: 12/11/2018 07:29 am »
Sure, I am aware about free-flyers, and there's no question about them being preferable from a disturbances (contamination and other types) point of view. But we're talking order-of-magnitude effects here, not optimal-yet-unrealizable (in the near term, with current platforms) architectures.

Do other VVs regularly pollute sensitive instruments almost 2 orders of magnitude over nominal limits during docked ops?

If so, why is this issue raised as an anomaly for Dragon, and why are the limits so conservative or the mitigation measures so lacking?

Because they are non volatiles

Using many more words than you do, I respectfully disagree.
They are, in fact, volatiles.
They persist on the cooled TQCMs but dissipate from the warm window of SAGE-III-ISS. 
That's why many optical windows have heaters.
They are unlikely to be RCS biproducts because complex hydrocarbons tend to solarize, polymerize in the harsh solar UV radiation, and accumulate for ever.  That's kind of stuff that will ruin instruments, particularly UV instruments.
The calculations of film thickness assume that the density of the condensibles is 1, like water.
In fact, water is a distinct possibility.  It could be absorbed by the SPAM on the Dragon while it's in the humid environment of the Cape and desorbed on orbit. 
Or it could be something that gets scrubbed by the atomic oxygen of LEO.
It could be much worse.  There are many examples, like the Stardust Navigation camera, that are.  (It was partially cleaned by accidentally pointing the camera at the Sun, but went from really clouded up to somewhat clouded up but usable for its Tempel 1 flyby.)

edit:  And Stardust was a "freeflyer", but had worse contamination, as did Meteor-3M, and others. 

The main reason to have freeflyers platforms for Columbus and ISS related mainly to RCS by-products.
All instruments on those platforms where to have covers deployed over the sensitive surfaces before maintenance vehicles were to come even close to the platforms (which was planned to happen roughly once per year).

Offline Jim

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Re: General Falcon and Dragon discussion (Thread 15)
« Reply #65 on: 12/12/2018 02:38 pm »
Sure, I am aware about free-flyers, and there's no question about them being preferable from a disturbances (contamination and other types) point of view. But we're talking order-of-magnitude effects here, not optimal-yet-unrealizable (in the near term, with current platforms) architectures.

Do other VVs regularly pollute sensitive instruments almost 2 orders of magnitude over nominal limits during docked ops?

If so, why is this issue raised as an anomaly for Dragon, and why are the limits so conservative or the mitigation measures so lacking?

Because they are non volatiles

Using many more words than you do, I respectfully disagree.
They are, in fact, volatiles.


I was going by what I heard, is that that the issue is NVRs because it is not going away like after other visiting vehicles leave.

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Re: General Falcon and Dragon discussion (Thread 15)
« Reply #66 on: 12/14/2018 02:29 am »
Okay - here's a (potentially stupid) question...


We've all seen recent photos peeking inside the interstage of a F9 booster, including the hydraulic actuators that articulate the grid fins. We've also been told by Mr Musk himself that the hydraulic pump that drives those actuators stalled.


My question is - what drives the pump? An electric motor? Doubt it - I think the battery for that would be too heavy. Is it a RP1 / O2 combustion chamber? High pressure HE? Somehow I doubt that too - seems like it would take a lot of HE. A gerbil? Anyone have an informed answer?
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Offline meekGee

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Re: General Falcon and Dragon discussion (Thread 15)
« Reply #67 on: 12/14/2018 03:12 am »
Okay - here's a (potentially stupid) question...


We've all seen recent photos peeking inside the interstage of a F9 booster, including the hydraulic actuators that articulate the grid fins. We've also been told by Mr Musk himself that the hydraulic pump that drives those actuators stalled.


My question is - what drives the pump? An electric motor? Doubt it - I think the battery for that would be too heavy. Is it a RP1 / O2 combustion chamber? High pressure HE? Somehow I doubt that too - seems like it would take a lot of HE. A gerbil? Anyone have an informed answer?
Do not have an informed answer.

Airplanes take power from one of the main engines, or from an APU...  Which in our case would be a powerpack.

But, for 1-2 minutes of operations?  Batteries is my guess.

-----
ABCD: Always Be Counting Down
« Last Edit: 12/14/2018 03:14 am by meekGee »
ABCD - Always Be Counting Down

Offline edkyle99

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Re: General Falcon and Dragon discussion (Thread 15)
« Reply #68 on: 12/15/2018 08:15 pm »
Ughh.  It's the time of the year for hyperbole not based on actual facts.  Note, however, that at least the story is more centered than the headline. 

"Elon Musk beat a world record for rocket launches in 2018"
https://www.businessinsider.my/spacex-falcon-9-commercial-rocket-record-most-launches-2018-12/

 - Ed Kyle

Offline meekGee

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Re: General Falcon and Dragon discussion (Thread 15)
« Reply #69 on: 12/16/2018 11:48 am »
Ughh.  It's the time of the year for hyperbole not based on actual facts.  Note, however, that at least the story is more centered than the headline. 

"Elon Musk beat a world record for rocket launches in 2018"
https://www.businessinsider.my/spacex-falcon-9-commercial-rocket-record-most-launches-2018-12/

 - Ed Kyle
That headline is correct in the same way some of the statistics you post are...

It is factually true, but it conveys a misleading message.

So for those who didn't bother reading, SpaceX did set a record this year for rocket launches...  Except it is for "most commercial rockets launched", which is a comparability weak record.  Their total number of launches was great but about the same as last year's.

The most important achievement, the increasing use of pre-flown rockets, is ignored.

The most important development - the maturation of BFS and of its commercial uses - were ignored as well.

In other words, we found an article about space where the author doesn't get it...

-----
ABCD: Always Be Counting Down

ABCD - Always Be Counting Down

Offline Comga

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Re: General Falcon and Dragon discussion (Thread 15)
« Reply #70 on: 12/16/2018 01:46 pm »
Sure, I am aware about free-flyers, and there's no question about them being preferable from a disturbances (contamination and other types) point of view. But we're talking order-of-magnitude effects here, not optimal-yet-unrealizable (in the near term, with current platforms) architectures.

Do other VVs regularly pollute sensitive instruments almost 2 orders of magnitude over nominal limits during docked ops?

If so, why is this issue raised as an anomaly for Dragon, and why are the limits so conservative or the mitigation measures so lacking?

Because they are non volatiles

Using many more words than you do, I respectfully disagree.
They are, in fact, volatiles.

I was going by what I heard, is that that the issue is NVRs because it is not going away like after other visiting vehicles leave.

But they do go away
The last graph in the paper shows that the loss of transmission, which is minor (~2%) even for SAGE-III-ISS’s most sensitive 290nm UV “channel” is highly correlated to the arrivals of Dragon capsules, but dissipates quickly. (The data is quite sparse, even though SAGE-III should get 18 readings a day.)
« Last Edit: 12/16/2018 04:49 pm by Comga »
What kind of wastrels would dump a perfectly good booster in the ocean after just one use?

Online spacenut

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Re: General Falcon and Dragon discussion (Thread 15)
« Reply #71 on: 12/16/2018 03:21 pm »
Ok, so how is the hydraulic system for the F9 powered?  Tesla battery?  The grid fins work without the engines running. 

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Re: General Falcon and Dragon discussion (Thread 15)
« Reply #72 on: 12/16/2018 03:49 pm »
Ok, so how is the hydraulic system for the F9 powered?  Tesla battery?  The grid fins work without the engines running.
If I had to guess, I would say pneumatic. In addition to some COPVs in the interstage (which could also be used for the stage separation system), there is a black device on the left side that looks similar to a Haskel pump.
I tried it at home

Offline edkyle99

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Re: General Falcon and Dragon discussion (Thread 15)
« Reply #73 on: 12/16/2018 05:57 pm »
Ughh.  It's the time of the year for hyperbole not based on actual facts.  Note, however, that at least the story is more centered than the headline. 

"Elon Musk beat a world record for rocket launches in 2018"
https://www.businessinsider.my/spacex-falcon-9-commercial-rocket-record-most-launches-2018-12/

 - Ed Kyle
So for those who didn't bother reading, SpaceX did set a record this year for rocket launches...  Except it is for "most commercial rockets launched", which is a comparability weak record.  Their total number of launches was great but about the same as last year's.

The most important achievement, the increasing use of pre-flown rockets, is ignored.

The most important development - the maturation of BFS and of its commercial uses - were ignored as well.

In other words, we found an article about space where the author doesn't get it...
"World Record" is almost always a bad choice.  Personally, I'm not interested in the "commercial" aspect.  The companies that built Atlas Agena and Thor Agena were commercial companies too.  The difference is only that government entities managed those programs.  The money still comes, in large part, from the government now, but SpaceX and ULA and Northrop Grumman run their own programs.

In my view, one of several great achievements by SpaceX in 2018 (and 2017) is that it performed the most U.S. orbital launches in a year for a specific rocket variant (19 so far for Falcon 9) since Atlas Agena in 1966 (24 launches, 1 failure) and for a family of U.S. rockets (20 so far) since Thor in 1969 (22 launches, 2 failures).   China's DF-5 based CZ family, of course, has set the bar even higher at 32 launches so far this year, taking us back to 1990 when R-7 performed 44 launches with 3 failures.  For real world records, one has to go back to 1980-81, when R-7 performed 61 successful orbital launches each year.

 - Ed Kyle

   
« Last Edit: 12/16/2018 05:59 pm by edkyle99 »

Offline gongora

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Re: General Falcon and Dragon discussion (Thread 15)
« Reply #74 on: 01/02/2019 11:19 pm »
My search skills are failing me tonight so I can't find the previous discussion on the topic here, but the Vertical Integration Study that DoD contracted from SpaceX (FA881818F0003) is still going.  There was additional funding in July and September 2018, and milestones out to at least April 2019.  Total potential value is up to $34,969,731.00.  One of the contract mods mentioned exercising an option for Phase 5 of the study, whatever that means.

In reference to another thread that popped up, I don't see DARPA contracts for SpaceX on the FPDS site, not sure why that is.

Offline Draggendrop

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Re: General Falcon and Dragon discussion (Thread 15)
« Reply #75 on: 01/16/2019 12:50 am »
Not sure if this has been posted...

Falcon User's Guide 2019
https://www.spacex.com/sites/spacex/files/falconusersguide.pdf

72 page pdf

Offline gongora

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Re: General Falcon and Dragon discussion (Thread 15)
« Reply #76 on: 01/16/2019 02:45 am »
Not sure if this has been posted...

Falcon User's Guide 2019
https://www.spacex.com/sites/spacex/files/falconusersguide.pdf

72 page pdf

Quote
Throttle capability Yes (190,000 lbf to 108,300 lbf sea level) Yes (220,500 lbf to 140,679 lbf)

edit: From the 2015 user guide that's an increased throttle range on first stage and a decreased throttle range on second stage?
« Last Edit: 01/16/2019 02:47 am by gongora »

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Re: General Falcon and Dragon discussion (Thread 15)
« Reply #77 on: 02/05/2019 10:04 pm »
Why has the Falcon Heavy had so little impact on NASA?

by National Space Society | Jan 21, 2019 | Commercial Space, Space Development

OPINION by Dale Skran, NSS Executive Vice President

https://space.nss.org/why-has-the-falcon-heavy-had-so-little-impact-on-nasa/

Offline woods170

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Re: General Falcon and Dragon discussion (Thread 15)
« Reply #78 on: 02/06/2019 10:27 am »
Why has the Falcon Heavy had so little impact on NASA?

by National Space Society | Jan 21, 2019 | Commercial Space, Space Development

OPINION by Dale Skran, NSS Executive Vice President

https://space.nss.org/why-has-the-falcon-heavy-had-so-little-impact-on-nasa/

Opinion peace full of cr*p IMO. The only reason why FH has had little  impact on NASA is because there are currently zero NASA missions available to fly on it.

Offline cuddihy

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Re: General Falcon and Dragon discussion (Thread 15)
« Reply #79 on: 02/06/2019 11:39 am »
I’d say the downturn in Geo SATCOM is more concerning. Though unclear how much of this is just a retrenchment after the effects of a short term glut caused by F9 launches in 2017/2018.

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Re: General Falcon and Dragon discussion (Thread 15)
« Reply #80 on: 02/06/2019 12:27 pm »
Why has the Falcon Heavy had so little impact on NASA?

by National Space Society | Jan 21, 2019 | Commercial Space, Space Development

OPINION by Dale Skran, NSS Executive Vice President

https://space.nss.org/why-has-the-falcon-heavy-had-so-little-impact-on-nasa/

This bit I find particularly curious:

Quote
The second reason the Falcon Heavy has not had a great impact thus far is that among key policymakers behind the scenes there is a rule of thumb that a launch vehicle needs to be flown successfully 10 consecutive times in order to be considered a reliable option for government flights. ... At this rate and with the 10 flight criteria being applied it might be 2022 or 2023 before the Falcon Heavy is considered ready for use by the government.

Atlas V flew MRO for NASA on it's 5th mission.
Delta IV flew a USAF payload on its 2nd mission.
Delta IV Heavy flew a USAF payload on its 2nd mission, and that after a partial failure.
Antares and Falcon 9 both flew NASA payloads to ISS on their 2nd flights.

Falcon Heavy is scheduled to fly a USAF payload on its 3rd flight, STP-2, and is certified for NSS payloads and has another USAF payload on the schedule.

NASA's certification standards state that a vehicle can be certified for Class B payloads (e.g. Discovery class) after only 1 flight of an evolved vehicle or 3 flights of a new vehicle.

...The only reason why FH has had little  impact on NASA is because there are currently zero NASA missions available to fly on it.

Not entirely true. NASA recently chose AV 401 to launch Lucy. That mission could have gone on FH, probably at considerably lower cost.
« Last Edit: 02/06/2019 12:32 pm by envy887 »

Offline Semmel

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Re: General Falcon and Dragon discussion (Thread 15)
« Reply #81 on: 02/06/2019 12:49 pm »
...The only reason why FH has had little  impact on NASA is because there are currently zero NASA missions available to fly on it.

Not entirely true. NASA recently chose AV 401 to launch Lucy. That mission could have gone on FH, probably at considerably lower cost.

I dont know, FH vs. AtlasV 401 .. doesnt seem to be a very big difference. Rumors have it that AtlasV 401 is about $110M and FH about $90M. A difference but not all that much. Also, SpaceX charges government extra over the minimal launch cost due to the pile of paper they have to produce. Not sure how that works for ULA.

In terms of launch success probability, as well as schedule stability, Atlas is still much better than FH. So these might have been factors and it wouldn't surprise me that these were deciding factors in the decision.

Offline envy887

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Re: General Falcon and Dragon discussion (Thread 15)
« Reply #82 on: 02/06/2019 01:05 pm »
...The only reason why FH has had little  impact on NASA is because there are currently zero NASA missions available to fly on it.

Not entirely true. NASA recently chose AV 401 to launch Lucy. That mission could have gone on FH, probably at considerably lower cost.

I dont know, FH vs. AtlasV 401 .. doesnt seem to be a very big difference. Rumors have it that AtlasV 401 is about $110M and FH about $90M. A difference but not all that much. Also, SpaceX charges government extra over the minimal launch cost due to the pile of paper they have to produce. Not sure how that works for ULA.

In terms of launch success probability, as well as schedule stability, Atlas is still much better than FH. So these might have been factors and it wouldn't surprise me that these were deciding factors in the decision.

NASA is paying $148 million for Lucy on a 401, while the USAF is paying $130 million to launch AFSPC-52 on FH. Not a huge difference, but cheaper nonetheless.

Also, the $90M for FH and $110M for 401 are not rumors. Those are the list prices for basic GTO launches on SpaceX and ULA websites. ULA has since taken the prices off the site, but SpaceX still lists theirs.
« Last Edit: 02/06/2019 03:09 pm by envy887 »

Offline niwax

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Re: General Falcon and Dragon discussion (Thread 15)
« Reply #83 on: 02/06/2019 02:00 pm »
...The only reason why FH has had little  impact on NASA is because there are currently zero NASA missions available to fly on it.

Not entirely true. NASA recently chose AV 401 to launch Lucy. That mission could have gone on FH, probably at considerably lower cost.

I dont know, FH vs. AtlasV 401 .. doesnt seem to be a very big difference. Rumors have it that AtlasV 401 is about $110M and FH about $90M. A difference but not all that much. Also, SpaceX charges government extra over the minimal launch cost due to the pile of paper they have to produce. Not sure how that works for ULA.

In terms of launch success probability, as well as schedule stability, Atlas is still much better than FH. So these might have been factors and it wouldn't surprise me that these were deciding factors in the decision.

NASA is paying $148 million for Lucy on a 401, while the USAF is paying $130 million to launch AFSPC-52 on FH. Not a huge difference, but cheaper nonetheless.

Also, the $90M for FH and $100M for 401 are not rumors. Those are the list prices for basic GTO launches on SpaceX and ULA websites. ULA has since taken the prices off the site, but SpaceX still lists theirs.

Still, I wouldn't fault NASA for choosing ULA on this one. Atlas 401 is a good rocket and the price is acceptable and within a reasonable range. I think the general sentiment about NASA underusing FH is missions that are planned on SLS or cost increases/feature reduction to stay within the performance of other rockets.
Which booster has the most soot? SpaceX booster launch history! (discussion)

Offline Semmel

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Re: General Falcon and Dragon discussion (Thread 15)
« Reply #84 on: 02/06/2019 03:39 pm »
...The only reason why FH has had little  impact on NASA is because there are currently zero NASA missions available to fly on it.

Not entirely true. NASA recently chose AV 401 to launch Lucy. That mission could have gone on FH, probably at considerably lower cost.

I dont know, FH vs. AtlasV 401 .. doesnt seem to be a very big difference. Rumors have it that AtlasV 401 is about $110M and FH about $90M. A difference but not all that much. Also, SpaceX charges government extra over the minimal launch cost due to the pile of paper they have to produce. Not sure how that works for ULA.

In terms of launch success probability, as well as schedule stability, Atlas is still much better than FH. So these might have been factors and it wouldn't surprise me that these were deciding factors in the decision.

NASA is paying $148 million for Lucy on a 401, while the USAF is paying $130 million to launch AFSPC-52 on FH. Not a huge difference, but cheaper nonetheless.

Also, the $90M for FH and $110M for 401 are not rumors. Those are the list prices for basic GTO launches on SpaceX and ULA websites. ULA has since taken the prices off the site, but SpaceX still lists theirs.

I took the $110M for 401 from wikipedia, which is why I called it a rumor. Anyway, you provide good data points with Lucy and AFSPC-52. Thanks!

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Re: General Falcon and Dragon discussion (Thread 15)
« Reply #85 on: 02/07/2019 07:39 am »
https://spaceflightnow.com/2019/02/06/first-unpiloted-test-flight-of-spacex-crew-dragon-capsule-reset-for-march-2/

Quote
As expected, NASA announced Wednesday that the first unpiloted test flight of a SpaceX Falcon 9 rocket and a Crew Dragon astronaut ferry ship has slipped from later this month to March 2. The first unpiloted flight of Boeing’s Starliner capsule is now targeted for the April timeframe.

In a statement posted on the agency’s website, NASA said the revised schedule will allow time for “completion of necessary hardware testing, data verification, remaining NASA and provider reviews, as well as training of flight controllers and mission managers.”

So about three more weeks and we'll the Crew Dragon in space. Fingers crossed.

Offline gongora

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Re: General Falcon and Dragon discussion (Thread 15)
« Reply #86 on: 02/07/2019 07:02 pm »
Tweet from Math Sundin
Quote
RUAG Space puts one ping pong ball in for every launch they are part of. @SpaceX designed their own and sent 500. @elonmusk

Update:
https://twitter.com/PeterGuggenbach/status/1093476774523080704

Offline woods170

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Re: General Falcon and Dragon discussion (Thread 15)
« Reply #87 on: 02/07/2019 07:35 pm »
Why has the Falcon Heavy had so little impact on NASA?

by National Space Society | Jan 21, 2019 | Commercial Space, Space Development

OPINION by Dale Skran, NSS Executive Vice President

https://space.nss.org/why-has-the-falcon-heavy-had-so-little-impact-on-nasa/

This bit I find particularly curious:

Quote
The second reason the Falcon Heavy has not had a great impact thus far is that among key policymakers behind the scenes there is a rule of thumb that a launch vehicle needs to be flown successfully 10 consecutive times in order to be considered a reliable option for government flights. ... At this rate and with the 10 flight criteria being applied it might be 2022 or 2023 before the Falcon Heavy is considered ready for use by the government.

Atlas V flew MRO for NASA on it's 5th mission.
Delta IV flew a USAF payload on its 2nd mission.
Delta IV Heavy flew a USAF payload on its 2nd mission, and that after a partial failure.
Antares and Falcon 9 both flew NASA payloads to ISS on their 2nd flights.

Falcon Heavy is scheduled to fly a USAF payload on its 3rd flight, STP-2, and is certified for NSS payloads and has another USAF payload on the schedule.

NASA's certification standards state that a vehicle can be certified for Class B payloads (e.g. Discovery class) after only 1 flight of an evolved vehicle or 3 flights of a new vehicle.

This is exactly why I referred to the article as a piece of cr*p. The author is making up stuff and stating it as "facts" whereas the actual facts (such as the list you gave) clearly show that the author of the article is full of cr*p.

Online OhYeah

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Re: General Falcon and Dragon discussion (Thread 15)
« Reply #88 on: 02/07/2019 10:08 pm »
This is exactly why I referred to the article as a piece of cr*p. The author is making up stuff and stating it as "facts" whereas the actual facts (such as the list you gave) clearly show that the author of the article is full of cr*p.

Wasn't the Air Force STP-2 payload supposed to be the *second* FH to launch but it got pushed way back into 2019? The author's claims have little basis in reality.

Offline gongora

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Re: General Falcon and Dragon discussion (Thread 15)
« Reply #89 on: 02/07/2019 10:20 pm »
STP-2 is basically a test launch, it's not awarded under the EELV program.

Offline docmordrid

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Re: General Falcon and Dragon discussion (Thread 15)
« Reply #90 on: 02/08/2019 12:02 am »
FH also has the classified USAF AFSPC 52 launch in 2020.

Space News...
« Last Edit: 02/08/2019 12:03 am by docmordrid »
DM

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Re: General Falcon and Dragon discussion (Thread 15)
« Reply #91 on: 02/12/2019 08:13 am »
Reported on Reddit.

SpaceX Launch Certification to Face Review by Pentagon Watchdog.

Quote
    Review to look at approval for Falcon 9, Falcon Heavy launches
    Memo to Air Force doesn’t say what prompted watchdog review

Is this good, bad or routine?
« Last Edit: 02/12/2019 08:14 am by jpo234 »
You want to be inspired by things. You want to wake up in the morning and think the future is going to be great. That's what being a spacefaring civilization is all about. It's about believing in the future and believing the future will be better than the past. And I can't think of anything more exciting than being out there among the stars.

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Re: General Falcon and Dragon discussion (Thread 15)
« Reply #92 on: 02/12/2019 12:52 pm »
I think Jeff Foust has a sensible take on this:

Quote from: @jeff_foust
Worth noting that just because an inspector general decides to audit a project doesn’t necessarily mean there’s a problem with it (a lesson I learned in a past career where I served as a quality manager at a small company with an ISO 9001 certification.) http://bit.ly/2Sqjulv

https://twitter.com/jeff_foust/status/1095318655842295808

Quote
Also, it’s not a bad idea to review the overall launch vehicle certification process given that the Air Force will be going through that process in the next few years with several other vehicles (New Glenn, OmegA, Vulcan.)

Edit to add: attached formal DoD notice of the audit
« Last Edit: 02/12/2019 12:58 pm by FutureSpaceTourist »

Offline edkyle99

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Re: General Falcon and Dragon discussion (Thread 15)
« Reply #93 on: 02/13/2019 05:47 pm »
"An official with knowledge of the company’s thinking, who spoke on the condition of anonymity, said that SpaceX was surprised by the announcement of the inspector general’s review and doesn’t know what prompted it."

https://www.washingtonpost.com/technology/2019/02/12/pentagon-watchdog-review-spacexs-certification-launch-national-security-satellites/?noredirect=on&utm_term=.3a8d0069be9a

 - Ed Kyle

Offline gongora

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Re: General Falcon and Dragon discussion (Thread 15)
« Reply #94 on: 02/13/2019 06:11 pm »
Speculation on what politicians you think are trying to screw SpaceX belongs in the Space Policy section, not here.

Offline Lar

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Re: General Falcon and Dragon discussion (Thread 15)
« Reply #95 on: 02/13/2019 08:34 pm »
Speculation on what politicians you think are trying to screw SpaceX belongs in the Space Policy section, not here.
Arguably it probably actually belongs on your facebook page or blog rather than here on NSF at all... but gongora's right it surely doesn't belong in this thread.
« Last Edit: 02/13/2019 08:34 pm by Lar »
"I think it would be great to be born on Earth and to die on Mars. Just hopefully not at the point of impact." -Elon Musk
"We're a little bit like the dog who caught the bus" - Musk after CRS-8 S1 successfully landed on ASDS OCISLY

Offline JohnR

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Re: General Falcon and Dragon discussion (Thread 15)
« Reply #96 on: 02/14/2019 12:06 am »
I've been searching and if I missed it, I am so very sorry for asking. Is the dry and/or wet mass of the trunk for the Crew Dragon known?

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Re: General Falcon and Dragon discussion (Thread 15)
« Reply #97 on: 02/17/2019 04:56 pm »
Will SpaceX Shut Europe Out of the Space Launch Market?

How do you say "we're losing the space race" in French?

By Rich Smith (TMFDitty)
Feb 17, 2019 at 7:10AM

https://www.fool.com/investing/2019/02/17/will-spacex-shut-europe-out-of-the-space-launch-ma.aspx

Offline woods170

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Re: General Falcon and Dragon discussion (Thread 15)
« Reply #98 on: 02/17/2019 06:36 pm »
Will SpaceX Shut Europe Out of the Space Launch Market?

How do you say "we're losing the space race" in French?

By Rich Smith (TMFDitty)
Feb 17, 2019 at 7:10AM

https://www.fool.com/investing/2019/02/17/will-spacex-shut-europe-out-of-the-space-launch-ma.aspx

What Space Race?

Sheesh, looks like each trash news-site these days is using the phrase "Space Race" to spice up its "articles".

Annoying.
« Last Edit: 02/18/2019 06:59 am by woods170 »

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