Author Topic: SpaceX Falcon 9 - Iridium NEXT Flight 1 DISCUSSION (Jan. 14 2017)  (Read 339515 times)

Offline Lar

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I read it that they wanted to launch all 81 but didn't have rides for all of them yet.

The system requires 66 for full coverage, any others would be on-orbit spares
« Last Edit: 07/14/2016 04:53 PM by Lar »
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Offline ZachS09

$492M / 9 =$54.7M  for each launch with a new rocket

It is 7 launches.

492/7 = 70.3 M but that probably includes the dispenser built by SpaceX.

Edit: The article says 7 launches. But it also says 81 satellites. I believe 2 will fly on a russian rocket. That still leaves 79, so 8 flights with 10 each unless they will have ground spares.

If Dnepr's unlikely, maybe a Proton or Soyuz can launch the other two Iridiums.
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Offline Nomadd

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Is the system still going to be 6 planes with 11 working sats each. that makes 7 launches of 10 sats seem a little odd. And, will some of the spares stay on the ground till needed?
« Last Edit: 07/14/2016 06:23 PM by Nomadd »

Offline IntoTheVoid

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Is the system still going to be 6 planes with 11 working sats each. that makes 7 launches of 10 sats seem a little odd. And, will some of the spares stay on the ground till needed?
70 launched by SpaceX, plus the 2 that were to be launched by the Russians first, would have been 72 orbital, allowing for 6 planes of 11 operational plus a spare. Sounds right to me.

Quote
The operational Iridium constellation requires 66 satellites — 11 spacecraft in six orbital planes — for global coverage serving more than 800,000 subscribers.

Enough Iridium Next satellites should be launched by the end of 2017 to fully replace the first-generation fleet, allowing controllers to retire and de-orbit the old spacecraft. Iridium has launch contracts with SpaceX and Kosmotras for 72 satellites, but Desch said the company plans to eventually launch all 81 birds.
https://spaceflightnow.com/2016/07/13/iridium-satellites-rolling-off-assembly-line-in-arizona/
« Last Edit: 07/14/2016 07:54 PM by IntoTheVoid »

Offline smh

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Is the system still going to be 6 planes with 11 working sats each. that makes 7 launches of 10 sats seem a little odd. And, will some of the spares stay on the ground till needed?
70 launched by SpaceX, plus the 2 that were to be launched by the Russians first, would have been 72 orbital, allowing for 6 planes of 11 operational plus a spare. Sounds right to me.
6 launches, 6 planes. How is the 7th launch going to get satelites to 6 (at least 4 if 2 by another launch provider) different planes?

Offline IntoTheVoid

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Spare satellites are usually held in a 414 mi (666 km) storage orbit.[2] These will be boosted to the correct altitude and put into service in case of a satellite failure. After the Iridium company emerged from bankruptcy the new owners decided to launch seven new spares, which would have ensured two spare satellites were available in each plane. As of 2009 not every plane has a spare satellite; however, the satellites can be moved to a different plane if required. A move can take several weeks and consumes fuel which will shorten the satellite's expected service life.

Significant orbital plane changes are normally very fuel-intensive, but orbital perturbations aid the process. The Earth's equatorial bulge causes the orbital right ascension of the ascending node (RAAN) to precess at a rate that depends mainly on the period and inclination. Iridium satellites have an inclination of 86.4°, so every satellite in a retrograde (inclination < 90°) orbit, their equator crossings steadily precess westward.[citation needed]

A spare Iridium satellite in the lower storage orbit has a shorter period so its RAAN moves westward more quickly than the satellites in the standard orbit. Iridium simply waits until the desired RAAN (i.e., the desired orbital plane) is reached and then raises the spare satellite to the standard altitude, fixing its orbital plane with respect to the constellation. Although this saves substantial amounts of fuel, it can be a time-consuming process.
https://en.wikipedia.org/wiki/Iridium_satellite_constellation

Based on the above, I'd guess that they'll all be dropped off in that storage orbit, and make their own way to the final orbital plane as Iridium sees fit.

Online Steven Pietrobon

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Edit: The article says 7 launches. But it also says 81 satellites. I believe 2 will fly on a russian rocket. That still leaves 79, so 8 flights with 10 each unless they will have ground spares.

From the article. That leaves nine satellites that don't yet have a launch.

"Iridium has launch contracts with SpaceX and Kosmotras for 72 satellites, but Desch said the company plans to eventually launch all 81 birds."
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Offline zubenelgenubi

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An observation from the amateur astronomer/visual satellite observer/UFO debunker perspective:

A full, operational Iridium Next constellation will mean the end of the "Iridium flare": the specular sunlight reflection from the MMA (Main Mission Antennas).  These flares reach a visual magnitude of -8.
http://www.satobs.org/iridium.html

The new satellite design will not produce these flares.

From Iridium satellites rolling off assembly line in Arizona
Quote
Enough Iridium Next satellites should be launched by the end of 2017 to fully replace the first-generation fleet, allowing controllers to retire and de-orbit the old spacecraft.

The impending end of an era!

To enjoy Iridium flares while you still can, predictions of such for your location can be found at:
http://www.heavens-above.com/
« Last Edit: 07/15/2016 06:01 AM by zubenelgenubi »
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Offline kevin-rf

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Well you do still have NOSS satellites and Envirosat can produce very nice flares.
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Online docmordrid

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I believe the lack of a Dnepr is due to the ongoing embargo foodfight. What are the odds that'll spill over io Proton and Soyuz?

Also, documenting the new SpaceX satellite dispenser shown in the article. 'CommX' too?
« Last Edit: 07/15/2016 03:32 PM by docmordrid »
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Offline gongora

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I believe the lack of a Dnepr is due to the ongoing embargo foodfight. What are the odds that'll spill over io Proton and Soyuz?

Also, documenting the new SpaceX satellite dispenser shown in the article. 'CommX' too?

Dnepr is a joint Ukrainian/Russian vehicle, which is why it is no longer flying.  It has nothing to do with Proton/Soyuz.

Online abaddon

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Also, documenting the new SpaceX satellite dispenser shown in the article. 'CommX' too?
I'd have to think this would be a valuable learning experience in building the CommX dispensers.  Thinking further along those lines, I imagine SpaceX "proper" would build the dispenser much like they did for Iridium in this case, while the "CommX" org would build the satellites.  They need to make sure that the launcher side of the business and the satellite side are properly separated to prevent even a whiff of impropriety.  That's starting to verge on off-topic though.

Offline zubenelgenubi

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re: Iridium flares
Well you do still have NOSS satellites and Envirosat can produce very nice flares.
True, but my incomplete understanding is that the Iridium flares are quite predictable, given that the satellite design, and therefore the geometry creating the flare, is well-understood and modeled.

I think NOSS flares prediction, and Envisat flares prediction, are not as well modeled.  There's still a substantial bit of chance whether or not one observes a flare on a particular pass (latitude/longitude/time).

(Actually, that makes those flares a different and also exciting challenge.)

And Iridium flares are SOOOO bright!

Satellite observers should continue to watch for flares from other satellites when these Iridiums are no more.

In the not-so-distant future, veteran observers will tell tales of Iridium flares to half-believing tenderhoof stargazers.

(I wonder if anyone has seen, briefly, their shadow cast by Iridium flare.  You'd need at minimum, a fully dark, un-light polluted sky.  Maybe freshly fallen snow as the shadow projection surface?)
« Last Edit: 07/16/2016 12:24 AM by zubenelgenubi »
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Online Steven Pietrobon

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Dnepr is a joint Ukrainian/Russian vehicle, which is why it is no longer flying.  It has nothing to do with Proton/Soyuz.

Despite what Spaceflightnow.com says, Dnepr has not been cancelled. ESA will be flying some of their QB50 satellites on it this year, probably with the two Iridium NEXT satellites.

https://www.qb50.eu/index.php/schedule
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Offline Nomadd

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 Will they be bringing the old sats down once NEXT is fully up? That would make for a good light show. Or is fuel too far gone for that?
« Last Edit: 07/16/2016 07:49 PM by Nomadd »

Offline zubenelgenubi

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Will they be bringing the old sats down once NEXT is fully up? That would make for a good light show. Or is fuel too far gone for that?
De-orbiting the old satellites, according to the SFN article referenced above.

To my knowledge, no one has ever de-orbited an entire satellite constellation.  How will this be executed?

My outsider's guess is the satellites will re-enter over remote ocean locations.  The South Pacific appears to be a favored location for this.

I'll voice my vote now for live video coverage of the re-entry event(s)!

A thought for producing a live web cast: sequential de-orbiting burns by the several satellites in one orbital plane as the orbital plane crosses the disposal zone, at night!  This would produce sequential fiery re-entries, all visible from one location!  The re-entries would span the sky, as the Earth turns under the orbital plane.

I believe the details of how the constellation disposal will be executed would make a great NSF follow-up article!
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Online Semmel

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De-orbiting satelits for show.. There is actually a "fireworks" display planned for the Japanese Olympic games opening in 2020 that consists of de-orbiting a few hundred little particles of some mm in size.

http://global.star-ale.com/project/canvas

Unfortunately this is completely off topic and might be better discussed in a separate thread.

Online Comga

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De-orbiting satelits for show.. There is actually a "fireworks" display planned for the Japanese Olympic games opening in 2020 that consists of de-orbiting a few hundred little particles of some mm in size.

http://global.star-ale.com/project/canvas

Unfortunately this is completely off topic and might be better discussed in a separate thread.

That proposal is utter gibberish that ignores all relevant facts about satellites.
This discussion seems to be trying to duplicate that.
Deorbiting the first generation Iridium constellation is a work task. They will do it in a manner that maximizes success, which is dumping each satellite in the South Pacific as far from people as they can get. It will be slow and controlled, not paced for show.

And it is off topic for the launch of Gen 2.

Back on topic, does anyone have an estimate for the mass of the dispenser?
What kind of wastrels would dump a perfectly good booster in the ocean after just one use?

Offline gongora

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Back on topic, does anyone have an estimate for the mass of the dispenser?

One of the articles said 1000kg, for total launch mass of 9600kg.

Edit:
SpaceNews: Iridium’s SpaceX launch slowed by Vandenberg bottleneck
Quote
Hawthorne, California-based SpaceX is building the 1,000-kilogram dispenser that will separate the 10 satellites into or bit on release from the rocket.

Each Iridium Next satellite will weigh 860 kilograms at launch, for a total satellite payload mass of 8,600 kilograms, plus the 1,000-kilogram dispenser
« Last Edit: 07/17/2016 03:23 PM by gongora »

Offline gongora

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Iridium Jul 15, 2016: First Falcon 9 Iridium NEXT Satellite Dispenser Arrives at Launch Site
Quote
On Tuesday, June 21st, SpaceX shipped the first Falcon 9 Iridium NEXT satellite dispenser to the Vandenberg Air Force Base launch site in California, and on Monday, June 27th, it was confirmed that the dispenser arrived safely. ...
In order to accommodate a payload of this size, SpaceX developed a Falcon 9 satellite dispenser unit that was capable of managing the critical-timed separation and deployment of ten satellites from each rocket. These dispensers were built out of a carbon fiber composite to reduce mass, minimize the total number of parts and simplify their composition while increasing structural stiffness and strength. The design of this dispenser places the Iridium NEXT satellite vehicles in two separate stacked tiers around the outside of each dispenser, holding five satellites per tier.
“We’re excited for the upcoming first launch of Iridium NEXT and proud of the work we’ve completed for the Iridium NEXT program. This is one of the heaviest payloads we will fly to-date – 10 Iridium NEXT satellites weighing over 20,000 pounds,” said Kris Kroc, mission manager at SpaceX.

Now that the dispenser is at the launch facility, the team will be running a series of end-to-end electrical tests with the tiers separated, as seen in the accompanying photo.
(photo copyright SpaceX)

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