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SpaceX Discussion Thread

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1 hour ago, CatastrophicFailure said:

What I meant was, as a starting point, such are the people who are most likely to, A: have the monetary means to do so, and B: are more willing to trade risk for something potentially awesome and experience-improving, especially if it’s from Musk. 

I completely disagree that Tesla buyers are likely to have bought their cars because they are Musk fans. I know several Tesla buyers, and not one has ever indicated any interest in Elon Musk or any of his other ventures.

The Tesla buyers I have known or talked to either liked the environmentalism of an electric car, the luxury experience of a Tesla, or the economics of not paying for gasoline. (Where I live, gas is more expensive than most places in the US, and electricity is less expensive than most places in the US.)

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14 minutes ago, mikegarrison said:

completely disagree that Tesla buyers are likely to have bought their cars because they are Musk fans. I know several Tesla buyers, and not one has ever indicated any interest in Elon Musk or any of his other ventures.

That isn’t at all what I said, you guys completely missed my point. But fine, agree to disagree. We’re just going in circles here. 

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2 hours ago, CatastrophicFailure said:

B: are more willing to trade risk for something potentially awesome and experience-improving, especially if it’s from Musk. 

It literally *is* what you said, actually: "especially if it’s from Musk"

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1 hour ago, mikegarrison said:

It literally *is* what you said, actually: "especially if it’s from Musk"

It literally is not, but I’m not going to sit here and argue semantics now. 

Moving on. 

Starlink update:

 

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2 hours ago, CatastrophicFailure said:

Starlink update:

 

Why de-orbit two healthy sats?

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Posted (edited)
12 minutes ago, Mitchz95 said:

Why de-orbit two healthy sats?

Sounds like they intentionally launched extra sats just in case some failed. The fine print in the tweet says "two sats will be intentionally deorbited in order to simulate end of life".

Edited by mikegarrison

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Actually it appears that the two healthy sats coming back are testing the deorbit process:

Quote

The rest of the 57 satellites have been working as intended, according to the company. Forty-five of the satellites have raised their altitudes with their onboard thrusters and have reached their final intended orbits of 342 miles (550 kilometers) up. Five of the satellites are still in the middle of raising their orbits, and another five are undergoing additional systems checks before they raise their orbits. As for the remaining two satellites, SpaceX intentionally fired their onboard thrusters with the goal of crashing them into the planet’s atmosphere. There wasn’t anything wrong with those satellites — the company just wanted to test the de-orbiting process.
https://www.theverge.com/2019/6/28/19154142/spacex-starlink-60-satellites-communication-internet-constellation

 

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According to the launch schedule app thingy I have on my phone, the next SpaceX launch is CRS-18 on the 22nd of July. When does SX’s contract with NASA for ISS resupplies end, and how many more CRS missions are they intended to fly?

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The go to ISS about 4 times a year. After Crew Dragon, they will still do them, and since they keep extending ISS, probably for a while.

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20 hours ago, mikegarrison said:

Sounds like they intentionally launched extra sats just in case some failed. The fine print in the tweet says "two sats will be intentionally deorbited in order to simulate end of life".

Yes they probably just needed 55, still weird they did not at least left 1 as an hot spare, if some of the defect ones had issues who let them control deorbit but not work well as an communication satellite they would work just as well for this experiment. For the real deal I assume they would use some satellites as hot spares. 

Hot spares is common for hard drives in raid arrays. One or more satellite is in an higher or lower orbit, if one of the operational satellites fails the spare will move in to replace it. 
For an system like starlink you will not have to launch single satellites to replace failed. 

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Posted (edited)

 

1 hour ago, RealKerbal3x said:

According to the launch schedule app thingy I have on my phone, the next SpaceX launch is CRS-18 on the 22nd of July. When does SX’s contract with NASA for ISS resupplies end, and how many more CRS missions are they intended to fly?

They have 3 more flights including the one in July*. The last phase 1 flight for SpaceX will be CRS-20 in March of 2020*. After that, it looks like they will continue the CRS-XX numbering scheme for future flights. https://en.wikipedia.org/wiki/Commercial_Resupply_Services

*dates subject to change.

23 hours ago, Barzon Kerman said:

oh no.

unknown.png 

I have come to celebrate this...

Edited by Racescort666

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For the starlink constellation it might be that you don't need a hot spare. Because you have so many sats in the same plane, you just space out the survivors and absorb a slight reduction in signal strength.

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On 6/29/2019 at 12:30 AM, Mitchz95 said:

Why de-orbit two healthy sats?

Cost of two satellites amongst the thousands that you’re manufacturing - negligible.

Value of being able to deal with your potential space junk problem (Having one’s Starship holed by one’s defunct satellite would be embarrassing) and showing the regulators, foreign space agencies and the public at large that you can - priceless.

 

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Posted (edited)
24 minutes ago, KSK said:

Cost of two satellites amongst the thousands that you’re manufacturing - negligible.

Value of being able to deal with your potential space junk problem (Having one’s Starship holed by one’s defunct satellite would be embarrassing) and showing the regulators, foreign space agencies and the public at large that you can - priceless.

 

De-orbiting the sick ones shows you can, since a healthy sat would presumably be able to do everything a sick sat could do and more. 

The only reasons I could see for de-orbiting healthy ones atm is that they may want to see how the healthy sats de-orbit specifically for some reason. Or there is some function the sick ones cant perform during de-orbit that SpaceX is interested in, like some kind of data collection about burning up mebe... Or the mark 1 constellation of these sats was only supposed to be so big and they have nowhere else to park the left over (presumably safety margin amount of) satellites.

The cost may be negligible when compared to the overall cost of the entire Starlink network but at the same time, no one is going to de-orbit perfectly good sats only because they didn't cost much in the scheme of things. There would have to be some specific reason.

Edited by Dale Christopher

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Spoiler
On 6/29/2019 at 2:30 AM, Mitchz95 said:

Why de-orbit two healthy sats?

A special 3.5% tax. Put 55, drop 2.

 

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I don't think they CAN deorbit the sick ones. They said those would deorbit naturally.

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22 minutes ago, Brotoro said:

I don't think they CAN deorbit the sick ones. They said those would deorbit naturally.

Oh? Interesting. 

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They had to get permission to launch these satellites.

Here's wikipedia:

Quote

SpaceX filed documents in late 2017 with the US FCC to clarify their space debris mitigation plan. The company will "implement an operations plan for the orderly de-orbit of satellites nearing the end of their useful lives (roughly five to seven years) at a rate far faster than is required under international standards. [Satellites] will de-orbit by propulsively moving to a disposal orbit from which they will reenter the Earth's atmosphere within approximately one year after completion of their mission."[28] In March 2018, the FCC issued SpaceX approval with some conditions. SpaceX would need to obtain a separate approval from the ITU.[29][30] The FCC supported a NASA request to ask SpaceX to achieve an even higher level of de-orbiting reliability than the standard that NASA had previously used for itself: reliably deorbiting 90% of the satellites after their missions are complete.[31]

So they had to get permission from the FCC to launch these satellites, and apparently NASA also was very concerned about them being able to de-orbit them. So I would expect that actually part of the plan was to prove that their de-orbit method would work, and the best way to prove that is to actually de-orbit some sats.

Thinking it over, I bet the plan all along was to intentionally de-orbit a few of them just to prove that they can.

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Yes, this is/was still very much a test mission, so its not a surprise that they test the deorbit capability of these things too.

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Posted (edited)
5 minutes ago, Xd the great said:

How much delta-V does a Starlink sateillte have? 100m/s? 200?

I believe 1500 m/s

(fuzzy memory)

Edited by Dale Christopher

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Musk's model of P2P is at the same stage where commercial aviation was at in the 1940s.

Then, airplanes were seen as a faster, if not safer alternative to cross the atlantic, as compared to slower, but safe and proven ships. Today, Starship P2P is seen as a faster, if not safer alternative to move around the world, as compared to slower, but safe and proven airplanes.

It's going to take a while though..

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