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General Falcon and Dragon discussion (Thread 15)
by
Chris Bergin
on 11 Sep, 2018 19:26
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#1
by
Asteroza
on 12 Oct, 2018 07:06
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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?
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#2
by
Jim
on 12 Oct, 2018 13:57
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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.
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#3
by
whitelancer64
on 12 Oct, 2018 14:20
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#4
by
abaddon
on 12 Oct, 2018 14:31
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#5
by
HarryM
on 12 Oct, 2018 16:52
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How many flights have the new COPV's had? Have they flown them yet?
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#6
by
whitelancer64
on 12 Oct, 2018 22:17
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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.
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#7
by
gongora
on 12 Oct, 2018 22:39
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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.
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#8
by
lucas071200
on 17 Oct, 2018 17:03
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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
Gesendet von meinem Aquaris X2 mit Tapatalk
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#9
by
docmordrid
on 17 Oct, 2018 23:05
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Below the booster nose cones and between the 3 octawebs there are longerons connecting the boosters to the center core.
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#10
by
gongora
on 27 Nov, 2018 14:14
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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.
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#11
by
Raul
on 28 Nov, 2018 12:08
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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.
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#12
by
gongora
on 28 Nov, 2018 14:28
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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.)
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#13
by
gongora
on 02 Dec, 2018 23:34
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SpaceX now has their NOAA license for the cameras on Dragon.
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#14
by
docmordrid
on 04 Dec, 2018 10:01
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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
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#15
by
MATTBLAK
on 04 Dec, 2018 10:05
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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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#16
by
docmordrid
on 04 Dec, 2018 10:40
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Sen. Shelby is going to need a bigger fire hose to put out all these grass fires.
From the Ars article
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."
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#17
by
MATTBLAK
on 04 Dec, 2018 10:44
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Sen. Shelby is going to need a bigger fire hose to put out all these grass fires.
From the Ars article
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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#18
by
LouScheffer
on 04 Dec, 2018 12:54
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From the Ars article
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.
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#19
by
woods170
on 04 Dec, 2018 13:52
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From the Ars article
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.
