Space In General

A Facebook post on the ISS deorbit was hilarious, with comments from that don't have the vaguest notion of how things work:

"Launch it into the sun!"

"Like the ocean needs more pollution."

"Crash it onto the moon, or Mars, not into the ocean."

"Disassemble it first and deorbit the individual pieces."

"Just move it to a higher, more stable orbit. It'll be a museum someday!"
 
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This little guy is Iris, a rover built by students at Carnegie Mellon university, and it's going to the moon this summer.
 
Booster 4 has been put on the orbital pad today. Starship 20 should be next, though as the tweet says it will have to be done with the chopsticks as the crane is not tall enough. All this ahead of Elon's Starship update presentation on Thursday.

 
Lens focusing has begun with the JWST, and it's already picking up some stray photons. But there's still a lot of very, veeeeeery precise work to be done:

To work together as a single mirror, the telescope’s 18 primary mirror segments need to match each other to a fraction of a wavelength of light – approximately 50 nanometers. To put this in perspective, if the Webb primary mirror were the size of the United States, each segment would be the size of Texas, and the team would need to line the height of those Texas-sized segments up with each other to an accuracy of about 1.5 inches.
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Starship 20 has been moved into position to be lifted with the chopsticks. Unknown if they will do it tonight or in the morning.

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24/7 live stream:

 
EngieDiesel
The Sun: Hey SpaceX, those are some nice satellites you just launched. Be a shame if anything happened to them...
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Yeah, a very minor solar storm has brought down an estimated 40 Starlink satellites!

From Spaceweather.com:

GEOMAGNETIC STORM BRINGS DOWN STARLINK SATELLITES: As many as 40 Starlink satellites are currently falling out of the sky--the surprising result of a minor geomagnetic storm. SpaceX made the announcementyesterday:

"On Thursday, Feb. 3rd at 1:13 p.m. EST, Falcon 9 launched 49 Starlink satellites to low Earth orbit from Launch Complex 39A (LC-39A) at Kennedy Space Center in Florida. ... Unfortunately, the satellites deployed on Thursday were significantly impacted by a geomagnetic storm on Friday, [Feb. 4th]."

​

Two days before launch a CME hit Earth's magnetic field. It was not a major space weather event. In fact, the weak impact did not at first spark any remarkable geomagnetic activity. However, as Earth passed through the CME's wake, some sputtering G1-class geomagnetic storms developed. It was one of these minor storms that caught the Starlink satellites on Feb. 4th.

Geomagnetic storms heat Earth's upper atmosphere. Diaphanous tendrils of warming air literally reached up and grabbed the Starlink satellites. According to SpaceX, onboard GPS devices detected atmospheric drag increasing "up to 50 percent higher than during previous launches."

"The Starlink team commanded the satellites into a safe-mode where they would fly edge-on (like a sheet of paper) to minimize drag," says SpaceX. "Preliminary analysis show the increased drag at the low altitudes prevented the satellites from leaving safe-mode to begin orbit raising maneuvers, and up to 40 of the satellites will reenter or already have reentered the Earth’s atmosphere."
 
Dotini
"The Starlink team commanded the satellites into a safe-mode where they would fly edge-on (like a sheet of paper) to minimize drag," says SpaceX. "Preliminary analysis show the increased drag at the low altitudes prevented the satellites from leaving safe-mode to begin orbit raising maneuvers, and up to 40 of the satellites will reenter or already have reentered the Earth’s atmosphere."
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Oh wow, that is NOT what I expected happened to them when I saw the headlines. This in particular: "the increased drag at the low altitudes prevented the satellites from leaving safe-mode " That's weird.

I can speculate as to what happened a bit. For example, it sounds like drag in safe mode was greater than expected (that's not necessarily the case), and that left the satellite in a higher drag situation following the event where it could not regain the necessary attitude to exit safe mode. But even if that's what happened (and I can think of weirder ways to fit that SpaceX quote), it's still an odd event. Drag is not that hard to calculate. Perhaps the safe mode attitude was somehow wrong to minimize drag. Or perhaps there is some commanding problem when it comes to exiting safe mode. So, for example, perhaps the safe mode attitude is perfect, and intended for this use, but someone forgot to model the increased drag environment for exiting safe mode. If that's the case, it's probably just a software update to prevent it from happening with other satellites.
 
Danoff
Oh wow, that is NOT what I expected happened to them when I saw the headlines. This in particular: "the increased drag at the low altitudes prevented the satellites from leaving safe-mode " That's weird.

I can speculate as to what happened a bit. For example, it sounds like drag in safe mode was greater than expected (that's not necessarily the case), and that left the satellite in a higher drag situation following the event where it could not regain the necessary attitude to exit safe mode. But even if that's what happened (and I can think of weirder ways to fit that SpaceX quote), it's still an odd event. Drag is not that hard to calculate. Perhaps the safe mode attitude was somehow wrong to minimize drag. Or perhaps there is some commanding problem when it comes to exiting safe mode. So, for example, perhaps the safe mode attitude is perfect, and intended for this use, but someone forgot to model the increased drag environment for exiting safe mode. If that's the case, it's probably just a software update to prevent it from happening with other satellites.
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As I understand it, the satellites were parked at a preparatory altitude prior to insertion to their final orbit altitude. They were at the particular altitude, ~130 miles, where the effect of even a mild solar storm was most serious to them.
 
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Dotini
As I understand it, the satellites were parked at a preparatory altitude prior to insertion to their final orbit altitude. They were at the particular altitude, ~130 miles, where the effect of even a mild solar storm was most serious to them.
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I have to think they expected that their techniques would work, otherwise that's a lot of risk.
 
Danoff
I have to think they expected that their techniques would work, otherwise that's a lot of risk.
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I believe the team was blissfully unaware of the solar storm and its potential threat to their satellites at that particular altitude. We are still learning about the complexities of space weather and its various interactions with our planet. One key "constant" that is actually changing is the progressive weakening of Earth's magnetosphere which allows increasing external affects from the cosmos on our planet.
 
After many delays throughout the day, Starship 20 has been lifted off of it's transport base by the catching arms aka chopsticks.

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Live stream:

 
My understanding of the Starlink solar storm thing is that the satellites are intentionally launched into a low orbit, so those that don't power up and pass initial startup pretty much automatically fall out of orbit, they won't have to be actively de-orbited, nor will they end up contributing to orbital clutter. Those that work properly are then raised to their final stable orbits. The result of the solar storm was that the upper atmosphere's drag was higher than normal, resulting in the satellites not having time to go through their initial startup and proper orbital insertion.

I have to love Facebook, just for the entertainment of reading posts from people who understand everything there is to know about rockets, orbits, and satellites. The initial low orbit is actually genius and very elegant. If a satellite ain't gonna work, its destruction is automatic and guaranteed. Once it works, it goes up to its permanent, safe position. But the questions from folks, like "Why risk them in a solar storm?" when you had how much warning about it? You know, since it didn't exist at launch time? "Why put them in a low orbit to start with?" completely ignoring the failsafe of automatically eliminating those that fail to initialize properly.

Facebook reinforces my signature line!
 
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Good news: The Mars InSight lander survived a particularly nasty dust storm that knocked it into safe mode last month.

The not so good news...

mars_insight.jpg


That's generally not what you want to see on your solar powered equipment. The probe has already finished its scheduled objectives and is currently on "as long as the funding holds up" mode, which was expected to be the end of this year. But if some of that doesn't get cleaned off, it may not make it to summer.
 
wfooshee
My understanding of the Starlink solar storm thing is that the satellites are intentionally launched into a low orbit, so those that don't power up and pass initial startup pretty much automatically fall out of orbit, they won't have to be actively de-orbited, nor will they end up contributing to orbital clutter. Those that work properly are then raised to their final stable orbits. The result of the solar storm was that the upper atmosphere's drag was higher than normal, resulting in the satellites not having time to go through their initial startup and proper orbital insertion.

I have to love Facebook, just for the entertainment of reading posts from people who understand everything there is to know about rockets, orbits, and satellites. The initial low orbit is actually genius and very elegant. If a satellite ain't gonna work, its destruction is automatic and guaranteed. Once it works, it goes up to its permanent, safe position. But the questions from folks, like "Why risk them in a solar storm?" when you had how much warning about it? You know, since it didn't exist at launch time? "Why put them in a low orbit to start with?" completely ignoring the failsafe of automatically eliminating those that fail to initialize properly.

Facebook reinforces my signature line!
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It's a bit odd to launch satellites that have that much chance of failing right away. But I still have to think that they were expecting to be able to survive the storm. It's a high risk situation to lose that many just because of a solar storm.

It looks like they're using hall thrusters, which means that inserting them at low orbital altitude and letting them do their own raise maneuvers is likely more efficient in terms of mass/money as well.
 
Danoff
It's a bit odd to launch satellites that have that much chance of failing right away. But I still have to think that they were expecting to be able to survive the storm. It's a high risk situation to lose that many just because of a solar storm.

It looks like they're using hall thrusters, which means that inserting them at low orbital altitude and letting them do their own raise maneuvers is likely more efficient in terms of mass/money as well.
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Krypton powered Ion thrusters. Not sure how different they are.

 
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R1600Turbo
Krypton powered Ion thrusters.
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They're hall thrusters. "Ion thruster" is not as specific as "Hall-effect Ion Thruster", and Krypton gas is the fuel source apparently. I'm more familiar with Xenon as a fuel source.
 
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Danoff
It's a bit odd to launch satellites that have that much chance of failing right away. But I still have to think that they were expecting to be able to survive the storm. It's a high risk situation to lose that many just because of a solar storm.

It looks like they're using hall thrusters, which means that inserting them at low orbital altitude and letting them do their own raise maneuvers is likely more efficient in terms of mass/money as well.
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It's not that they're so likely to fail right away, it's more that if they do, there's no housekeeping to take care of. If it fails, it falls out of the sky. If it starts up OK, it goes on to a stable orbit. No orbital debris to take care of. As for surviving the storm, I still haven't seen anything that said they were aware of the storm or its effects at launch time, and one article actually said they declined to comment on whether they were aware of any space weather at the time.
 
3 years, left to right.

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Edit: arms have released Starship and opened up.

Screenshot_20220210-171403_YouTube.jpg


Here's the live stream link for the presentation tonight, 9pm EST.

 
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wfooshee
It's not that they're so likely to fail right away, it's more that if they do, there's no housekeeping to take care of. If it fails, it falls out of the sky. If it starts up OK, it goes on to a stable orbit. No orbital debris to take care of. As for surviving the storm, I still haven't seen anything that said they were aware of the storm or its effects at launch time, and one article actually said they declined to comment on whether they were aware of any space weather at the time.
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Well for low thrust, if you have the time, you generally want to deliver to the lowest orbit possible because the ISP of the spacecraft is so much higher than the ISP of the upper stage. They had a plan for the increased drag from the solar storm, it just didn't work out. I bet it works better next time.
 
From today's edition of Spaceweather.com:


24 HOURS LATER: A CME hit Earth's magnetic field on Feb. 9th. The geomagnetic storm (category G1) erupted 24 hours later. "Auroras burst into life over the coast of Scotland," reports Alan C. Tough, who sends this picture from the seaside village of Hopeman:​
​
What took so long? The storm waited a whole day while Earth moved deeper into the CME's wake. More than 3 millon kilometers behind the shock front, Earth encountered the kind of intense south-pointing magnetic fields that spark geomagnetic storms. See the data.
This kind of delay is not unusual. Minor CMEs, like the one that struck on Feb. 9th, often fail to produce a storm on first contact; the initial blow is not enough. The CME's wake can be more effective, sparking storms one or two days later.
Magnetometer readings obtained by Stuart Green in Preston UK highlight the delay between the CME impact on Feb. 9th and geomagnetic unrest on Feb. 10th:

The CME itself caused no obvious ripple in Green's recording. Nevertheless, a storm was coming; G1 conditions were detected for more than 6 hours on Feb. 10th. Interestingly, the Starlink Incident of Feb. 4th was caused by just such a delayed storm.​
 

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