Author Topic: SpaceX F9 : Starlink v0.9 : May 23, 2019 - DISCUSSION (Read 238123 times)

gongora · « **Reply #100 on:** 05/10/2019 04:09 pm »

Gwynne mentioned 3-7 flights (including this one), with at least one of those being operational sats. That seems to mean only one or two flights of the initial "up to 75" generation of test sats. There is really no problem with fitting in these launches, they have plenty of launch capacity.

matthewkantar · « **Reply #101 on:** 05/10/2019 04:10 pm »

If F9 is volume limited, one way to squeeze more sats in the fairing is to have the sats be the dispenser. Imagine daisy chaining them all together and having them release each other in turn. This would mean more structure to the individual units, but maybe less weight overall per sat. Might make the sats less demisable upon reentry.

This is the sort of out-of-the-box thinking SpaceX is known for, but maybe not worth tackling if a much more capable system is on its way?

kessdawg · « **Reply #102 on:** 05/10/2019 04:31 pm »

Would the weight of that additional structure then reduce the satellite's on orbit useful life by needing more fuel to maintain orbit? If so, might not be worth it.

satcomopsuk · « **Reply #103 on:** 05/11/2019 08:24 am »

Launch track ......

Image..

110252Z MAY 19
NAVAREA IV 408/19(11,12,26).
WESTERN NORTH ATLANTIC.
FLORIDA.
1. HAZARDOUS OPERATIONS, ROCKET LAUNCHING
160225Z TO 160452Z, ALTERNATE 170225Z TO
170452Z MAY IN AREAS BOUND BY:
A. 28-36-28N 080-35-36W, 29-06-00N 080-07-00W,
29-04-00N 080-04-00W, 28-53-00N 080-11-00W,
28-36-00N 080-24-00W, 28-31-00N 080-33-17W,
28-31-59N 080-33-42W.
B. 32-08-00N 077-13-00W, 32-48-00N 076-53-00W,
33-49-00N 075-53-00W, 34-00-00N 075-21-00W,
33-39-00N 074-44-00W, 33-08-00N 074-44-00W,
31-58-00N 077-03-00W.
2. CANCEL THIS MSG 170552Z MAY 19.

rsdavis9 · « **Reply #104 on:** 05/11/2019 11:58 am »

What is the number of satellites per plane for full deployment? I'm thinking they may want to use full planes for initial testing. That way they can test full earth relay if they have enough ground stations.

ThomasGadd · « **Reply #105 on:** 05/11/2019 02:16 pm »

Quote from: rsdavis9 on 05/11/2019 11:58 am

What is the number of satellites per plane for full deployment? I'm thinking they may want to use full planes for initial testing. That way they can test full earth relay if they have enough ground stations.

66 satellites per plane. 6 ground stations. No inter-satellites links.
They can do store and forward testing.

rsdavis9 · « **Reply #106 on:** 05/11/2019 03:06 pm »

Quote from: ThomasGadd on 05/11/2019 02:16 pm

Quote from: rsdavis9 on 05/11/2019 11:58 am
What is the number of satellites per plane for full deployment? I'm thinking they may want to use full planes for initial testing. That way they can test full earth relay if they have enough ground stations.

66 satellites per plane. 6 ground stations. No inter-satellites links.
They can do store and forward testing.

Store and forward meaning: store packets and wait for ground station to come into view? But with enough ground stations they could do straight relay? Probably 66 ground stations.

macpacheco · « **Reply #107 on:** 05/11/2019 03:33 pm »

Quote from: rsdavis9 on 05/11/2019 03:06 pm

Quote from: ThomasGadd on 05/11/2019 02:16 pm
Quote from: rsdavis9 on 05/11/2019 11:58 am
What is the number of satellites per plane for full deployment? I'm thinking they may want to use full planes for initial testing. That way they can test full earth relay if they have enough ground stations.

66 satellites per plane. 6 ground stations. No inter-satellites links.
They can do store and forward testing.

Store and forward meaning: store packets and wait for ground station to come into view? But with enough ground stations they could do straight relay? Probably 66 ground stations.

An educated guess would be to provide coverage for a limited area where they have ground stations and satellite coverage 24x7. It is testing after all. Perhaps Western USA only.

cyloncat · « **Reply #108 on:** 05/11/2019 03:36 pm »

Quote from: rsdavis9 on 05/11/2019 03:06 pm

Quote from: ThomasGadd on 05/11/2019 02:16 pm
Quote from: rsdavis9 on 05/11/2019 11:58 am
What is the number of satellites per plane for full deployment? I'm thinking they may want to use full planes for initial testing. That way they can test full earth relay if they have enough ground stations.

66 satellites per plane. 6 ground stations. No inter-satellites links.
They can do store and forward testing.

Store and forward meaning: store packets and wait for ground station to come into view? But with enough ground stations they could do straight relay? Probably 66 ground stations.

Store, forward to the next node, hold until the next node acknowledges receipt. Depending on transmission rate, capacity, reliability, etc., not every message may be acknowledged; bulk or implicit acknowledgement may be used, and if the receiving node realizes it has missed a packet, it will likely request retransmit. Sending node will store only until it knows that there will be no need to retransmit.

Nomadd · « **Reply #109 on:** 05/11/2019 03:44 pm »

Quote from: kessdawg on 05/10/2019 04:31 pm

Would the weight of that additional structure then reduce the satellite's on orbit useful life by needing more fuel to maintain orbit? If so, might not be worth it.

No. More weight would make the sat would stay up longer if drag was the same. A feather balloon is going to deorbit a lot faster than a lead balloon the same size.
The amount of fuel used only depends on drag. A 3 foot sphere that weighed six grams would require the same fuel to maintain orbit as a 3 foot sphere that weighed six tons. (Admitting that there are a hundred real world complications to that)

Robotbeat · « **Reply #110 on:** 05/11/2019 04:16 pm »

Quote from: matthewkantar on 05/10/2019 04:10 pm

If F9 is volume limited, one way to squeeze more sats in the fairing is to have the sats be the dispenser. Imagine daisy chaining them all together and having them release each other in turn. This would mean more structure to the individual units, but maybe less weight overall per sat. Might make the sats less demisable upon reentry.

This is the sort of out-of-the-box thinking SpaceX is known for, but maybe not worth tackling if a much more capable system is on its way?

The Boeing 702sp satellites were designed to stack on top of one another in this way.

Herb Schaltegger · « **Reply #111 on:** 05/11/2019 06:35 pm »

Quote from: macpacheco on 05/11/2019 03:33 pm

An educated guess would be to provide coverage for a limited area where they have ground stations and satellite coverage 24x7. It is testing after all. Perhaps Western USA only.

Didn’t Gongora post some FCC licensing paperwork that indicated testing of ground terminals in the DC/NoVa region? Or am I imagining that?

gongora · « **Reply #112 on:** 05/11/2019 06:48 pm »

Merrillan, WI Ku ES
Greenville, PA Ku ES
Redmond, WA Ku ES
Hawthorne, CA Ku ES
North Bend, WA Ku ES
Brewster, WA TT&C ES
Conrad, MT Ku Earth Station

meekGee · « **Reply #113 on:** 05/12/2019 01:49 am »

https://twitter.com/elonmusk/status/1127388838362378241

Now we know. 60!

ThePonjaX · « **Reply #114 on:** 05/12/2019 02:00 am »

60! That's insane. It's going to be very fun to look the deploy of this.

Seems they are going to need a lot less launches than expected to get the starlink working.

OneSpeed · « **Reply #115 on:** 05/12/2019 02:03 am »

Four stacks of 15 on a custom PAF, or is it 2 stacks of 30?

ZachS09 · « **Reply #116 on:** 05/12/2019 02:10 am »

https://space.skyrocket.de/doc_sdat/starlink-1.htm

If each Starlink sat is 387 kilograms, and there's 60 all together, that's an estimated total payload mass of 23,220 kilograms (not including the dispenser).

gongora · « **Reply #117 on:** 05/12/2019 02:16 am »

I think the satellite design has evolved since those mass numbers came out.

oldAtlas_Eguy · « **Reply #118 on:** 05/12/2019 02:16 am »

Quote from: ZachS09 on 05/12/2019 02:10 am

https://space.skyrocket.de/doc_sdat/starlink-1.htm

If each Starlink sat is 387 kilograms, and there's 60 all together, that's an estimated total payload mass of 23,220 kilograms (not including the dispenser).

Looks to be no dispenser.

They are stacked on top of each other.

Also looks to be 2 stacks of 30 rectangular flat ~ .3 m thick.

At 250 kg will be a total of ~16mt.

jaufgang · « **Reply #119 on:** 05/12/2019 02:23 am »

Quote from: oldAtlas_Eguy on 05/12/2019 02:16 am

Looks to be no dispenser.

They are stacked on top of each other.

Also looks to be 2 stacks of 30 rectangular flat ~ .3 m thick.

Looks like a stack of lawn chairs, each ready to pop open into a new shape. But lawn chairs don't have propellant tanks and maneuvering thrusters. Remarkable engineering!

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