ISS News and Discussion

[ecarfan]

At space.com — NASA delays spacewalk a 2nd time due to leak on International Space Station

A spacewalk last set for Thursday (Oct. 19) will now happen later in 2023 as NASAand Russia's federal space agency, Roscosmos, continue their analysis, NASA officials stated. The coolant used on the International Space Station (ISS) is ammonia, which requires extra decontamination procedures if spacesuited astronauts are nearby. "The coolant is not toxic or hazardous for the crew, but experts are discussing how to best keep small traces of the substance from getting into some internal systems to avoid equipment degradation over time," NASA officials wrote in a blog post Monday (Oct. 16).

To say that ammonia

is not toxic or hazardous for the crew

is a very strange statement In my opinion. Maybe they mean it is not a hazard when it is being vented into space and not inside the station. But it is a hazard, obviously.

Roscosmos plans its own spacewalk on Oct. 25 to examine the 13-year-old relocated radiator from the Rassvet module up close, from which the newest leak on Nauka appeared to originate.

The Russians are certainly taking their time on trying to figure out the cause of the leak.

 

[JB47394]

Maybe they mean it is not a hazard when it is being vented into space and not inside the station.

I think the idea is that if there's an active leak of ammonia on the exterior and they send crew out, their suits could get contaminated and then bring the ammonia back into the station. Then it would work its way through the station's life support systems.

 

[ecarfan]

Latest NSF This Week in Spaceflight video covers the recent Russian ISS spacewalk to look at the backup radiator coolant leak. They isolated the radiator and then started to inspect the leak when they observed more ammonia coolant being sprayed from a large glob of it adhering to a support structure next to the corner of the radiator. They had to abort that task. Mission not accomplished. The cosmonauts also were tasked with deploying a nano sat which apparently did not deploy its solar cell, and then they were supposed to deploy another solar panel on a synthetic radar comm system but the panel would not deploy. Not a good day in space on the Russian side.

 

[ecarfan]

In other ISS news, two female NASA astronauts are scheduled to do a spacewalk next week. I thought there was an issue with the suits onboard the ISS not being properly sized for smaller people. Maybe these two women are big enough to manage the suits that are available.

 

[JB47394]

I thought there was an issue with the suits onboard the ISS not being properly sized for smaller people.

They tried the first all-woman spacewalk on March 29, 2019, but they had prepared one large and one medium spacesuit. The spacewalk leader realized that, despite being trained in both sizes, she wasn't comfortable doing the spacewalk in the large.

All-Female Spacewalk Was Cancelled on 'My Recommendation,' Astronaut Anne McClain Says

"That was my recommendation," she said.

www.space.com

They then pulled it off October 18, 2019 by using two medium spacesuits.

NASA Astronauts Make History with 1st All-Woman Spacewalk

Astronauts Christina Koch and Jessica Meir complete the first spacewalk with an all-women team.

www.space.com

Christina Koch (left) is 5'9". I couldn't find a height for Jessica Meir, but she looks to be maybe an inch shorter.

 

[Electroman]

Latest NSF This Week in Spaceflight video covers the recent Russian ISS spacewalk to look at the backup radiator coolant leak. They isolated the radiator and then started to inspect the leak when they observed more ammonia coolant being sprayed from a large glob of it adhering to a support structure next to the corner of the radiator. They had to abort that task. Mission not accomplished. The cosmonauts also were tasked with deploying a nano sat which apparently did not deploy its solar cell, and then they were supposed to deploy another solar panel on a synthetic radar comm system but the panel would not deploy. Not a good day in space on the Russian side.

View attachment 985987View attachment 985988

I always wondered what would the orbits of satellites released from ISS and Space Shuttle be ? Won’t it always directly be in the path of ISS (and Shuttle)?

 

[JB47394]

I always wondered what would the orbits of satellites released from ISS and Space Shuttle be ? Won’t it always directly be in the path of ISS (and Shuttle)?

The nanosats are launched with a little velocity, so they occupy a slightly different orbit, resulting in a different amount of time to orbit the Earth. For a nanosat to get in the way of the ISS, the nanosat would have to complete an extra orbit of the Earth relative to the ISS. If nanosats are released at 10 km/s, that means that it takes 170 days to catch up to the ISS again. After that much time, the two orbits are so out of synch that they'd miss each other by perhaps tens of kilometers, with a relative speed of 10 km/h. Note that the various nanosats occupy elliptical orbits while the ISS orbit is kept almost perfectly circular.

Perhaps the elephant in the room, however, is atmospheric effects. The atmosphere is tenuous at the ISS' altitude, but it's there. The ISS orbit is slowly decaying all the time, requiring regular boosts. The satellites being released don't have engines, so they deorbit within 60 days to two years.

The bottom line is that the released nanosats aren't in the ISS's orbit because of the nanosat launch velocity combined with the consequences of operating in the fringes of the atmosphere.

 

[ggr]

If nanosats are released at 10 km/s, that means that it takes 170 days to catch up to the ISS again.

Did you mean 10 m/s? 10km/s is pretty fast...

 

[bxr140]

Did you mean 10 m/s? 10km/s is pretty fast...

Yes on units, and deployment velocities from dispensers are typically low single digits.

In context of the failure, cubesats are often container sized months before launch, and it’s a pretty hands off exercise from there until deployment. Solar arrays typically deploy as soon as the cubesat exits the dispenser— the only thing keeping the arrays stowed is the dispenser box itself. In that scenario, it is unlikely that the Russians carry any blame for the cubesat solar array deployment failure.

There HAVE been a few manual release cubesats during spacewalks over the years. I don’t know if that’s the case here, but in that scenario, it is plausible that the cosmonaut disrupted the solar deployment mechanism or in some other way damaged the cubesat.

 

[JB47394]

Did you mean 10 m/s? 10km/s is pretty fast...

Dangit. It's supposed to be 10 km/h at release and at interception.

I originally wrote 10 km/s both times - while meaning to write 10 km/h both times. I spotted one of the mistakes, but not the other. Thanks for pointing that out.

 

[Grendal]

NASA open to extending ISS beyond 2030

A NASA official opened the door to keeping the International Space Station in operation beyond 2030 if commercial space stations are not yet ready.

spacenews.com

 

[MontyFloyd]

NASA open to extending ISS beyond 2030

A NASA official opened the door to keeping the International Space Station in operation beyond 2030 if commercial space stations are not yet ready.

spacenews.com

Spent all that effort to get it up there, keep it up there.

Possible to use in new station as storage modules, remove the old items and use as hull, could be sealed most of time for safety.

 

[ecarfan]

Really? Again?​

Air is leaking from a Russian ISS module, but 'no impact to crew,' NASA says​

The space station has a leak at the aft end of the Russian module where the nation's Progress spacecraft dock to the orbital lab, said NASA's International Space Station (ISS) Program Manager Joel Mantalbano during a press briefing on Wednesday (Feb. 28) at NASA's Kennedy Space Center here, which was held to discuss SpaceX's upcoming Crew-8 astronaut mission to the ISS.
"I'd say that area is about three feet [0.9 meters] or so in length," Montalbano said. "We’re working with our Russian colleagues on the next step. Not an impact right now on the crew safety or vehicle operations, but something for everybody to be aware of."
The leak has no impact on the Crew-8 mission, Montalbano added,

 

[Grendal]

I'm reminded of this scene from "Hunt For Red October."

"Andrei. You've got another leak?"

 

[ecarfan]

And by the way, to say that air leaking from the ISS “has no impact to crew”; if I was one of the crew I would definitely disagree! While it may be a very slow leak, and my physiology may not detect it, my brain would definitely be impacted. I would be anxiously wondering if it was going to get worse and if there were more leaks coming in the future from the Russian side.

And this…

"I'd say that area is about three feet [0.9 meters] or so in length," Montalbano said.

What does that mean? There is a three foot crack? I don’t believe that is the case as that would be scary from a structural integrity aspect. So what is that guy describing? Amazing that he doesn’t clarify.

 

[TunaBug]

Really? Again?​

Air is leaking from a Russian ISS module, but 'no impact to crew,' NASA says​

Two things went through my head when I read about it this morning

• Perhaps the Russian micrometeorite shielding isn't as effective as the American?
• Perhaps this is what the beginning of the Keppler Syndrome looks like?

 

[scaesare]

At what point does this start to look like some sort of materials or manufacturing/process defect?

IIRC these all weren't necessarily on welds/seams... so some sort of material contamination during manufacture maybe?

It reminds me of issues they were having with the SR-71... the titanium they used for much of the fuselage was experiencing issues, and they couldn't figure out why until they noticed differences in when they manufactured them.

It turns out the chlorine in the water supply was more significant in summer, and it corroded the titanium. They switched to distilled water to wash the parts and problem solved. (Interesting read)

Maybe something similar... some sort of issue that has made the material brittle or otherwise degrade over time?

 

[ecarfan]

At what point does this start to look like some sort of materials or manufacturing/process defect?

Right now we don’t have enough information from NASA to do any sort of amateur analysis. The leak is in an “area” on the Russian side “about 3 feet in length”. That is not very helpful. Clearly it’s not a 3 foot long crack. It’s a leak somewhere in a 3 foot long area.

 

[JB47394]

The leak is in an “area” on the Russian side “about 3 feet in length”. That is not very helpful.

This is pure speculation, of course, but to me, that sounds like they know that the leak is coming from a welded seam that is three feet long. That suggests that some tiny flaw in a weld finally yielded to a pressure leak after years of thermal cycling.

 

[ecarfan]

This is pure speculation, of course, but to me, that sounds like they know that the leak is coming from a welded seam that is three feet long. That suggests that some tiny flaw in a weld finally yielded to a pressure leak after years of thermal cycling.

Understood we are just speculating, but if that is the situation it seems potentially very serious.

So this “area” is “at the aft end of the Russian module where the nation's Progress spacecraft dock”. That is the Russian Service Module, correct? That module is critical. Actually, I assume they are all critical.