SpaceX Successfully Launches a New Batch of Its Starlink Satellites

SpaceX on Monday successfully sent another batch of Starlink satellites into orbit but didn't quite stick the landing of its Falcon 9 rocket. From a report: Elon Musk's space company did achieve its primary objective of sending 60 more flying nodes for its nascent global broadband service into space, bringing the total number of Starlink satellites in low-Earth orbit to nearly 300. A secondary goal for the fifth Starlink mission, as with most SpaceX launches, was to recover the first stage of the Falcon 9 by landing it on a droneship stationed in the Atlantic Ocean. But this time the rocket missed the mark by a smidge. At the time it was expected to land, the live webcast from the droneship showed smoke or steam just off camera as the Falcon 9 made a "soft water landing." SpaceX reported during the webcast that the rocket appears to be intact and floating on the ocean, but it remains unclear whether it can be recovered. The booster had a useful life, having already launched three earlier SpaceX missions in 2019 before Monday's Starlink mission. Had it landed successfully, it would have been the 50th successful booster landing for the company. Now we may have to wait until the next planned Falcon 9 launch on March 2 to see that milestone.

Mars landing

[timeOday]

Has SpaceX ever said how they plan to be landing on Mars eventually? It seems like a lot of unmanned missions have made it all the way to Mars (or, the moon) and then went splat. And how do you get in practice runs beforehand?

Re:Mars landing

[fahrbot-bot]

Has SpaceX ever said how they plan to be landing on Mars eventually?

First, they'll send the drone ship for the boosters to land on, then ...

Re:

[BKDotCom]

How do they land the drone ship?

Drone ships all the way down?

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[Pascoea]

Send enough of them there, eventually you just land on the top of the pile and climb down.

Re:

[Gavagai80]

Landing a probe on Mars isn't difficult. The problem is that powered landings have been too insanely expensive to contemplate, so everybody has been trying to cut corners and trust their luck with passive braking. The SpaceX plan is a huge cheap incredibly powerful vehicle with orbital refueling -- so they don't have to be as clever. I presume they'll try to bleed some velocity with the same skydiver maneuver they'll be using during the Earth landing process, but any difficulties just mean you take that muc

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[PPH]

how they plan to be landing on Mars

Fill space with enough garbage and then walk over.

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[Immerman]

>Has SpaceX ever said how they plan to be landing on Mars eventually?

Repeatedly. Seems like the last few annual presentations have even included animations.

Basically, Starship will broadside through the atmosphere to shed as much speed as possible using its heat shield, then fire up the engines and do a propulsive landing, pretty much the same way the Falcon 9 booster does on Earth.

They probably won't shed nearly as much speed through the atmosphere as on Earth, which increases the fuel requirements fo

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[quenda]

They probably won't shed nearly as much speed through the atmosphere as on Earth, which increases the fuel requirements for propulsive braking, but escape/reentry speed is a lot slower on Mars,

There are plenty of delta-V maps of the solar system online, and Musk has claimed 6.9km/s capability for Starship with 100 tons payload.
From LEO (low earth orbit) to Mars surface needs around 10km/s, - 4 to reach Mars transfer, and 6 to slow down.
So you either need to shed a few km/s in Mars atmosphere, or refuel in a highly elliptical orbit like GTO.

It looks like a low-earth refuel is already needing around 10 BFR tanker launches, high orbit far more.
Using aero-braking on Mars for a single S

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[Immerman]

>So you either need to shed a few km/s in Mars atmosphere, or refuel in a highly elliptical orbit like GTO.
All the plans I've heard involve the highly-elliptical orbit. But I'd be willing to bet you could shed at least a couple km/s in the Mars atmosphere too, especially since Starship is designed to have far more control during reentry than a simple capsule - come in at a low angle and pitch the ship to "surf" the atmosphere rather just hitting it broadside. You don't have to do powered braking until

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[quenda]

Starship is designed to have far more control during reentry than a simple capsule -

Capsules are not that "simple". Except when they do a ballistic reentry [quora.com]. A capsule bottom is an aerodynamic lifting surface, and it has control, by shifting the centre of gravity, or by using thrusters. They don't just "hit it broadside". Apollo capsules had to reenter much faster than the shuttle ever did.

Scott Manley explains [youtube.com]

And obviously the cost of buying fuel on earth is not a big part of the cost of refuelling in space, duh! I was just trying to illustrate the magnitude of the task of a fully pro

Bad news

[Jzanu]

I'd prefer to read about the mitigation efforts designed to enable astronomy than more launches of pointless satellites destined to be obsolete junk in 5 years and pointless junk before that. Maybe Mr. Musk plans to start an orbital trash collecting business cleaning up his own mess. Catching junk at 35 km/s would be revolutionary and essential to prevent total orbital denial. Anti-satellite weapons will make a demand inevitably, so there is that.

Re:Bad news

[timeOday]

Going up to catch them would be silly, they will de-orbit and self-destruct no problem.

I find it hard to imagine astronomy cannot adapt. Ground-based astronomy has always had to deal with atmospheric conditions. Unlike clouds, Starlink never goes away for a while, but on the flipside it's entirely predictable, and how much of the sky does it actually fill?

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[Guspaz]

Per Musk:

Satellite albedo will drop significantly on almost every successive launch

Would it be nice to get more details? Sure. But they've already said they're experimenting with coatings for the satellites to improve the situation, and that albedo would be reduced when they're in an actual deployed configuration.

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[thegarbz]

But they've already said they're experimenting with coatings for the satellites to improve the situation

Good guy Musk making promises of something he can't guarantee has any hope in having any affect to try and shed some personal heat. Seems to have worked too what with everyone jumping to their defense like this. I wonder if it makes the problem 99% better, does it get to counteract the fact that they are planning on increasing the number of satellites in space by 2000%?

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[Xylantiel]

Nobody is saying that astronomy can't adapt in general. They're saying that SpaceX have consistently been jerks about this. Satellite companies and others work with radio astronomers on mitigation all the time, but SpaceX basically just didn't bother trying to figure this out despite it being obvious that it would be a problem for optical astronomy. We went through this already on a smaller scale decades ago with the Iridium satellites. To your "predictable" point... That has been actually one of the pr

Re: Bad news

[j.a.mcguire]

Dont think he needs to catch them, believe he can deorbit them.

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[AmiMoJo]

I'd just be happy if we didn't have to hear about every bowel movement.

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[Pascoea]

If they'd just hurry up and make clicking on links not mandatory, that would save a lot time not reading stuff we weren't interested in.

Who missed who?

[fahrbot-bot]

But this time the rocket missed the mark by a smidge.

Did the booster miss the ship or did the ship miss the booster -- it wasn't where is was suppose to be? Anyone know the method/protocol used to coordinate the locations of these two vehicles? I imagine it can't be just/simply GPS.

Re:Who missed who?

[crow]

I think the rocket is programmed to aim to just miss the barge, and then shift over at the last second with the final burn, but that shift is only done if everything looks good so that they don't risk destroying the barge. I expect once they've analyzed the data, they'll announce why it failed, and it was something that caused it to not think landing on the barge was safe.

This is just like when the center booster missed on the first Falcon Heavy launch, only that one was not a soft landing.

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[fahrbot-bot]

I expect once they've analyzed the data, they'll announce why it failed, and it was something that caused it to not think landing on the barge was safe.

Thanks. I noticed in the video that the ship was rocking a bit in the waves/swells. Didn't look like much, but perhaps it was deemed too much for a safe landing on the deck.

Re:Who missed who?

[Gavagai80]

Swells certainly weren't an issue, the sea was calmer than usual. They were trying a brand new more demanding orbit than they'd done with any previous mission, and they announced on the webcast that it was going to make landing more difficult. Presumably they ran out of fuel or hydraulic fluid or some other essential a few seconds early, which happened before on early attempts. Now they have to decide whether to try to carry more, or just go back to the old Starlink orbits that take longer.

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[Kjella]

This is just like when the center booster missed on the first Falcon Heavy launch, only that one was not a soft landing.

In that case the landing burn didn't fire, so it's not like the computer had any choice. We've seen it come down fairly hard and explode before, as long as the Falcon isn't smashing into it like a supersonic missile the barge will be fine and the conditions looked smooth. I'm guessing most likely a loss of control authority, that a grid fin or thruster malfunctioned. I think Musk at some point said something like that the primary mission is critical and recovery is a bonus, so there's much less redundancy o

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[Pascoea]

I'm going to go with the booster missed the ship. I'd have to imagine the ship's only job is to hold its point as accurately as possible, with the rocket adjusting course as needed. I can't imagine the ship being 50' off its designated spot would affect the landing, there has to be some system (I'm thinking like the ILS on commercial airliners) that can "find" the ship and adjust course as needed. Inertial navigation and GPS get you to the ballpark, but there has to be something to get you to home plate.

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[bill_mcgonigle]

> I'm going to go with the booster missed the ship. I'd have to imagine the ship's only job is to hold its point as accurately as possible, with the rocket adjusting course as needed.

The default landing maneuver is to aim for a near miss and then adjust to an actual landing on the ship if everything looks perfect. It's supposed to miss the ship if there's a problem. At this point it's easier to build a new booster than a new ASDS.

So, either there was a problem or an error caused the rocket to think the

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[Pascoea]

Yeah, there was a lot of discussion around this maneuver when the other booster failed to land at the cape. Would love to hear more discussion around how the rocket "finds" the ship. Even with the maneuver you're discussing, the rocket needs to know where it's going fairly precisely. Maybe it's as simple as GPS/Inertial, but I'd suspect there's something more "fun" going on.

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[crow]

I haven't been able to find anything about this online. Do you have a source?

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[110010001000]

Sure, electrek.co and Teslarati.com is where I get all my inside info.

Rei

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[PPH]

What fell off of stage one at T+6:00 min? Visible in the video. Looks like some sort of cable.

Re: What happened to the booster

[Åke Malmgren]

That was answered by a social media representative commenting as Elon Musk on the YouTube livestream. I don't recall what it was, and I'm on mobile and can't search for it now that it's buried in 1k comments. It was fairly early after it happened, maybe 200 comments in.