Author Topic: SpaceX Falcon 9 - AMOS-6 - (Pad Failure) - DISCUSSION THREAD (1)  (Read 1541325 times)

Offline dkovacic

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The big problem with this method is that it would take A Very Long TimeTM.  Sure, your all-electric bird has a great Isp.  But what its engines don't have is very much actual thrust, so it ends up taking "forever" to raise the orbit.  This is a potential problem for 2 reasons.  1. You've lost revenue generating time to orbit raising time.  Depending on a company's economic analysis, maybe this is okay.  It could theoretically be made up for by lengthening the satellite's lifetime on orbit.  2. It means that the satellite also ends up spending quite a long time getting through the Van Allen radiation belts, which is not good for the hardware on the satellite.

I guess Eutelsat 115 West B already made the transfer using all electric propulsion and is now operational? Edit and ABS-3A?

Here's a paper with a bunch of plots of various tradeoffs for this strategy:
http://erps.spacegrant.org/uploads/images/images/iepc_articledownload_1988-2007/2007index/IEPC-2007-287.pdf

Great link, thanks!  Just as a note though, macpacheco was talking about going from LEO to GEO, not GTO to GEO.  Though, I should have made clear that he already mentioned my "problem #1" in his post.

This is a great link, it basically shows the tradeoffs and you can simply see that low apogee greatly enhances days spent in LEO and going through Van-Allen belts. A rough estimate would be that LEO-GEO would be at least two times longer than GTO-GEO.
There is a third reason to avoid LEO as starting point for orbit raising - occultation effect. In LEO, satellite spends almost 50% in the Earths shadow, lasting 45 minutes. This leads to frequent temperature cycles. GEO comsats do carry batteries to continue operating during occultation periods, but these are not needed frequently roughly 1h per day during 60 days per year, totaling around 900 charge-discharge cycles for the lifetime of the satellite. Compare it to 200-day orbit raising from LEO with 8 cycles per day leading to 1600 cycles.

So I think pure LEO-to-GEO using electric propulsion is not really viable right now, despite 3x lower launch cost per kg. Various trade offs could be made for all-electric satellites launched to elliptical orbits. For example, 200x5000km orbit requires roughly 1km/s dV from LEO, perigee could be raised above 1200km in less than 10 days, reducing collision hazards and avoiding or reducing propulsion through Earths shadow. Unfortunately, as Figure 2 in the quoted document shows, there is no trick to avoid excessive passing through inner Van-Allen radiation belt - cumulative time will be at least 10 times longer than for GTO starting point.


Offline FutureSpaceTourist

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Peter B. de Selding ‏@pbdes 6m6 minutes ago

Spacecom of Israel: We are planning for an Aug. 22 launch, on SpaceX Falcon 9, of our Amos-6 Ku-/Ka-band telecom sat for 4 deg W.

https://twitter.com/pbdes/status/745918143797862401

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Date updated in the thread title.
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Offline Kabloona

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FCC has posted the latest transmitter permit application here:

https://apps.fcc.gov/oetcf/els/reports/STA_Print.cfm?mode=current&application_seq=72213&RequestTimeout=1000

Drone ship coordinates are:

28 6 11 N
74 34 0 W

This is about 45 miles west of the JCSAT-14 coordinates, ie closer to the Cape. This is quite a change, since the SES-9, JCSAT-14, Thaicom-8, and Eutelsat/ABS ASDS positions were all within 11 miles or so of each other.

The AMOS-6 launch date has just been announced as August 22, so this permit may be for AMOS-6, which is listed as 5500 kg. That's 700 kg more than JCSAT-14, which could explain the big difference in ASDS positions.

Also, 5500 kg is probably the upper limit for stage 1 recovery on GTO missions. The SpaceX F9 "capabilities" web page gives an F9 price of $62M for payloads up to 5500 kg to GTO. And LouScheffer's calculations have deduced an upper limit in this ballpark as well.

So AMOS-6 may turn out to be another "limiting case" stage 1 recovery experiment for SpaceX.
« Last Edit: 06/23/2016 02:21 pm by Kabloona »

Offline gongora

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FCC has posted the latest transmitter permit application here:

https://apps.fcc.gov/oetcf/els/reports/STA_Print.cfm?mode=current&application_seq=72213&RequestTimeout=1000

Drone ship coordinates are:

28 6 11 N
74 34 0 W

This is about 45 miles west of the JCSAT-14 coordinates, ie closer to the Cape. This is quite a change, since the SES-9, JCSAT-14, Thaicom-8, and Eutelsat/ABS ASDS positions were all within 11 miles or so of each other.

The AMOS-6 launch date has just been announced as August 22, so this permit may be for AMOS-6, which is listed as 5500 kg. That's 700 kg more than JCSAT-14, which could explain the big difference in ASDS positions.

Also, 5500 kg is probably the upper limit for stage 1 recovery on GTO missions. The SpaceX F9 "capabilities" web page gives an F9 price of $62M for payloads up to 5500 kg to GTO. And LouScheffer's calculations have deduced an upper limit in this ballpark as well.

So AMOS-6 may turn out to be another "limiting case" stage 1 recovery experiment for SpaceX.

So we really don't have any idea yet which launch this is for?

Offline Kabloona

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So we really don't have any idea yet which launch this is for?

The applications usually don't say which commercial customer the launch is for, so it's a bit of a guessing game. But based on the dates given in the permit, it's probably the next GTO launch, which is apparently either JCSAT-16 or AMOS-6, so we can narrow it down to those two possibilities.

Beyond that, roll your own dice. I'm guessing the 5500 kg AMOS-6 explains the significant difference in ASDS positions, but it's admittedly only a guess.
« Last Edit: 06/23/2016 02:55 pm by Kabloona »

Offline zubenelgenubi

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BUMP: AMOS 6 payload and Falcon 9 hardware

I'm guessing that since no one has reported any deliveries to the Cape, none of the hardware has arrived yet?

Any news of cargo aircraft inbound from Israel landing at the Skid Strip or the SLF?

We're a few days over 1 month from the launch date.
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Offline FutureSpaceTourist

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Peter B. de Selding ‏@pbdes 20m20 minutes ago

New target date for SpaceX launch of Spacecom's Amos-6 geo telecom satellite is 3-4 Sept (was 22 Aug.)

https://twitter.com/pbdes/status/758222044911771648

Offline Ilikeboosterrockets

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Stage 1 possibly spotted headed towards McGregor by reddit user groundedengineer.

https://www.reddit.com/r/spacex/comments/4vfesm/saw_what_looked_like_a_black_shrink_wrapped/

Offline The Roadie

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JCSAT 14 returned stage (fuselage 024) removed from McGregor test stand this morning after three full duration tests. Presumably to allow 029 to be erected for AMOS-6 testing.

Reported in the Facebook group by member Keith Wallace.
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Offline Tuts36

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Any word on where the first stage is at this time?  Could the ongoing flooding & highway closures in LA (including sections of I-10 & I-12) cause a significant delay?

EDIT: Ugh, sorry. Please move to discussion thread if needs be :/
« Last Edit: 08/16/2016 04:10 pm by Tuts36 »

Offline Ben the Space Brit

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According to Reddit, the core is now en-route to SLC-40 after completing its full-duration test burn at McGreggor.
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Offline linxiaoyi

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According to Reddit, the core is now en-route to SLC-40 after completing its full-duration test burn at McGreggor.

That's just a speculation
Quote
Hopefully the stage is on its way to the Cape after the (reported) successful full engine burn at McGregor. If the stage arrives this weekend that would be 3 weeks away from a Sept. 3/4 launch date. ~3 weeks is the recent cadence between stage arrival at the Cape and launch.
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Offline cuddihy

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Yes, doutbful at this moment (8/17) -- I-10 and I-12 are both still experiencing total closures east of Baton Rouge due to the historic flooding: http://m.roadnow.com/i10/traffic_state.php?i=4&from=f and there's a lot of road work in progress, who knows if there's any lane closures. I'd think SpaceX would wait a couple more days.

Offline joncz

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Hopefully then SpaceX will decide to reroute up to I-20 through Atlanta. :D

Offline Herb Schaltegger

According to Reddit, the core is now en-route to SLC-40 after completing its full-duration test burn at McGreggor.

That's just a speculation

There's L2 information about this, by the way.
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Offline ZachS09

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Let me guess this: the MECO-1 time for this mission will be around 156 seconds after launch...

I'm just making an assumption, by the way.
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Offline gongora

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Drone Ship Coordinates:
North  28  8  52    West  73  49  48    Autonomous Drone Ship

Offline Kabloona

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FCC has posted the latest transmitter permit application here:

https://apps.fcc.gov/oetcf/els/reports/STA_Print.cfm?mode=current&application_seq=72213&RequestTimeout=1000

Drone ship coordinates are:

28 6 11 N
74 34 0 W

This is about 45 miles west of the JCSAT-14 coordinates, ie closer to the Cape. This is quite a change, since the SES-9, JCSAT-14, Thaicom-8, and Eutelsat/ABS ASDS positions were all within 11 miles or so of each other.

The AMOS-6 launch date has just been announced as August 22, so this permit may be for AMOS-6, which is listed as 5500 kg. That's 700 kg more than JCSAT-14, which could explain the big difference in ASDS positions.

Also, 5500 kg is probably the upper limit for stage 1 recovery on GTO missions. The SpaceX F9 "capabilities" web page gives an F9 price of $62M for payloads up to 5500 kg to GTO. And LouScheffer's calculations have deduced an upper limit in this ballpark as well.

So AMOS-6 may turn out to be another "limiting case" stage 1 recovery experiment for SpaceX.

So we really don't have any idea yet which launch this is for?

In hindsight, that must have been for JCSAT-16. That position being 45 miles west of the JCSAT-14 position might explain why JCSAT-16 came back in better condition and why they had enough propellant to do a single engine landing burn.

Now back to AMOS-6...
« Last Edit: 08/17/2016 10:59 pm by Kabloona »

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