Celebratory Gunfire Brings Down a Satellite

[dasmiller]

These days, most satellites are prepared for decommissioning; they have a fuel reserve, and there is a programme ready for either inducing a (fairly) safe re-entry, or placing them in a parking orbit (whichever is appropriate), but I don't think they gave that as much thought 20 years ago.

That depended very much on the project. For example, all of the GEO commsats that I'm aware of (going back to the 1980s) carried fuel for deorbit*, and I can assure you that they analyzed the **** out of the deorbit procedures, fuel allocations, etc. I'm not sure they had the same requirements on the LEOs since the LEOs will eventually deorbit by themselves, as in this case. But I'm reasonably certain that they had to do a detailed reentry risk analysis to convince . . . umm . . .someone (I'm not sure who) that it was reasonably unlikely that the spacecraft would kill anyone.

Also, whatever the precautions, if communications break down, there is really little you can do, except wait for the fireworks.

Generally true, though I've worked on systems that were required to have an autonomous deorbit capability. These always lead to tricky systems architecture issues and I don't know if any have actually flown.

*"Deorbit" is a general term that simply means moving the spacecraft away from its operational orbit. It doesn't necessarily mean bringing the spacecraft down into the atmosphere.

 

[spin0]

These days, most satellites are prepared for decommissioning; they have a fuel reserve, and there is a programme ready for either inducing a (fairly) safe re-entry, or placing them in a parking orbit (whichever is appropriate), but I don't think they gave that as much thought 20 years ago.

UARS mission was conseived and developed during 80's (1979-). In those days it was thought that the space shuttle would bring decomissioned satellites back from orbit and this was the idea for UARS decomissioning also.

So they did initiate a re-entry, but can't control it better than that. Well, at least this one won't be adding to the junk-heap up there.

Yes, and there were some issues complicating the final burns in 2005. There was some uncertainty about remaining fuel, and they had to keep a safe distance to ISS.
Here's a good overview of UARS end-of-mission plans and operations:
Development and Execution of End-of-Mission Operations - Case Study of the UARS and ERBS End-of-Mission Plans (ppt)

 

[dasmiller]

UARS mission was conseived and developed during 80's (1979-). In those days it was thought that the space shuttle would bring decomissioned satellites back from orbit and this was the idea for UARS decomissioning also.

I'd forgotten that they thought like that back then. SV recovery seems like such a hazardous operation now that I can't imagine them agreeing to it, but they actually did spacecraft recoveries back in the '80s.

 

[ben m]

I'd forgotten that they thought like that back then. SV recovery seems like such a hazardous operation now that I can't imagine them agreeing to it, but they actually did spacecraft recoveries back in the '80s.

Remember that in the 70s, they also thought that they'd be launching the Space Shuttle once a week. This stuff was hoped to become routine and non-hazardous.

It's something to think about whenever your favorite futurist proposes a "moon base". In the 60s and 70s it was easy to picture this in the old sci-fi-film mode: "Dave, the ambifacient wane shaft is side-fumbling again." "OK, let's put on space suits and go have a look." <they do.> "Whack it with the wrench a few times." "Didn't work. I'll shinny up it and tighten the spurving bearing. Give me a leg up."

In reality, having seen how these things work, it'd be more like:

"Dave, Houston here. Support Team Gamma is working out a checklist for an ambifacient wane shaft repair. There's a sharp corner near the handhold which poses a glove puncture hazard, they're trying to find a way around it."
"Roger that. Shiela is left-handed, if that helps."
"Negative. We're testing a wrench extension, have the lunar machinist standing by."
"Standing by." <hours pass.>
"Dave, Houston here. We need some more data. You are authorized to plan a moonwalk to diagnose the problem. This will be designated Surface Excursion 105-A. Put together an excursion crew and do the usual indoor dry runs. We're sending an excursion checklist now."

 

[I Ratant]

Remember that in the 70s, they also thought that they'd be launching the Space Shuttle once a week. This stuff was hoped to become routine and non-hazardous.

It's something to think about whenever your favorite futurist proposes a "moon base". In the 60s and 70s it was easy to picture this in the old sci-fi-film mode: "Dave, the ambifacient wane shaft is side-fumbling again." "OK, let's put on space suits and go have a look." <they do.> "Whack it with the wrench a few times." "Didn't work. I'll shinny up it and tighten the spurving bearing. Give me a leg up."

In reality, having seen how these things work, it'd be more like:

"Dave, Houston here. Support Team Gamma is working out a checklist for an ambifacient wane shaft repair. There's a sharp corner near the handhold which poses a glove puncture hazard, they're trying to find a way around it."
"Roger that. Shiela is left-handed, if that helps."
"Negative. We're testing a wrench extension, have the lunar machinist standing by."
"Standing by." <hours pass.>
"Dave, Houston here. We need some more data. You are authorized to plan a moonwalk to diagnose the problem. This will be designated Surface Excursion 105-A. Put together an excursion crew and do the usual indoor dry runs. We're sending an excursion checklist now."

.
Yes, that IS the way NASA operates!
When Columbia landed at Edwards, Lockheed Flight Test donated the use of our weighing system to get the as-landed weight.
The Shuttle came in as scheduled, but the removal from the lakebed was delayed.. we had been told it would off the lakebed at 10:00... Hadn't gotten that far by 14:00...
Major stumbling block... one of the procedures at NASA Edwards was for some system to dump a major quantity of water, which flowed across the path the Shuttle would be taking to get to the scales.
When it got to the water, the tug pulling it was deemed insufficiently powerful to pull it through the wet sand.
The solution... Call Houston.
They mulled over the situation, and came up with an answer...
"Use a bigger tug".
Brilliant.
That's why those guys in Houston got the big bucks!
The total paralysis in the system that prevented independent activities without the imprimatur of Houston was risible!

 

[ben m]

"Use a bigger tug".
Brilliant.
That's why those guys in Houston got the big bucks!
The total paralysis in the system that prevented independent activities without the imprimatur of Houston was risible!

But I'm sympathetic to both sides, really. Buried among every 100 stories about absurdly-heavily-cross-checked procedures, there's an additional horror story about a non-cross-checked procedure going wrong.

"So then some genius at Edwards hooked up this giant tug, and it ripped the nose gear off and caused $1B damage. It turned out that they'd ignored the tug spec. In fact, the nose-gear engineer who had written the spec was at Marshall the whole time but nobody asked him. This illustrates once again NASA's flawed management and communications culture, about which something must be done ... "

I'm not sure which way the balance falls.

 

[I Ratant]

The yanking off the nose gear would be a possibility of course...
But that could have occurred with the Houston approval.
What was ultimately silly was the problem with the larger tug when it got the Shuttle to the weighing gear.
It had insufficient ground clearance to clear the weighing pads.
Another call to Houston.....
.
All of this could have been avoided had the drain procedure not occurred on schedule, but been delayed until the Shuttle was on the taxiway, off the lakebed.

 

[dasmiller]

All of this could have been avoided had the drain procedure not occurred on schedule, but been delayed until the Shuttle was on the taxiway, off the lakebed.

You're suggesting a deviation from the approved drain procedure schedule?

At a minimum, that would involve approval from Facilities, Site Maintenance, Security, Safety, Planning, and QA. And to start the approval process, you'd need the shuttle PM to write up a proper request document, complete with an evaluation of alternatives, assessment of risks, and (most important) a charge number. And that request would have to be drafted, reviewed, modified, re-reviewed, and finally signed off by everyone who could conceivably be affected by something like this (and "something like this" means "exactly like this except that any or all of the particulars might be different." So, for example, the person responsible for checking the windshield for cracks would be affected because the tires might get wet).

[/sarcasm] (just in case)

 

[spin0]

I'd forgotten that they thought like that back then. SV recovery seems like such a hazardous operation now that I can't imagine them agreeing to it, but they actually did spacecraft recoveries back in the '80s.

Man, those were the days... free-flying astronaut with a jet-pack flies to a rotating satellite, grabs it and starts to manouver it - in the middle of frikkin space!

In those days spirits were brave, the stakes were high, men were real men, women were real women and small furry creatures from Alpha Centauri were real small furry creatures from Alpha Centauri.

Here's a good description plus an amazing video of the feat: The Astronaut Who Caught a Satellite

After Challenger disaster the "jet-pack" Manned Maneuvering Unit was retired. But they did some retrievals in the 90's too using the arm. Here's a list (don't know if complete):

1984 STS-51-A Discovery
Retrieved two communication satellites stranded onto wrong orbit.

The chinese bought it. Yes, really.

1990 STS-32 Columbia
Retrieval of NASA's Long Duration Exposure Facility experiment.

1993 STS-57 Endeavour
Retrieval of ESA's European Retrievable Carrier experiment/observatory.

1996 STS-72 Endeavour
Retrieved japanese research spacecraft Space Flyer Unit.

Shuttle retrieval of UARS was considered in May 2001 and at the time it at least appeared feasible:
"EVA Project Office personnel supported a concept review for the possible Space Shuttle retrieval of the UARS on May 3, 2001. At this point, several different options are still under consideration. The mission would require at least one scheduled EVA to secure various deployable components on the spacecraft. UARS was originally designed to be compatible with EVA operations, so most of the tasks appear to be feasible."
NASA Studying Shuttle Retrieval of Upper Atmosphere Research Satellite (UARS)

But in October it was decided not to proceed with it:
"UARS RETRIEVAL - It was decided at the meeting yesterday that there
will not be a Space Shuttle retrieval of the UARS."
http://webcache.googleusercontent.c...tml+shuttle+uars+retrieval&cd=2&hl=fi&ct=clnk
I don't know the reasoning behind the decision, but my guess is maybe it was considered not feasible after all.

 

[I Ratant]

You're suggesting a deviation from the approved drain procedure schedule?

At a minimum, that would involve approval from Facilities, Site Maintenance, Security, Safety, Planning, and QA. And to start the approval process, you'd need the shuttle PM to write up a proper request document, complete with an evaluation of alternatives, assessment of risks, and (most important) a charge number. And that request would have to be drafted, reviewed, modified, re-reviewed, and finally signed off by everyone who could conceivably be affected by something like this (and "something like this" means "exactly like this except that any or all of the particulars might be different." So, for example, the person responsible for checking the windshield for cracks would be affected because the tires might get wet).

[/sarcasm] (just in case)

.
Yup.
That's it in a nuts shell.
Just following orders...

 

[dogjones]

Some really great posting Spin0, many thanks for both of them!

 

[Pardalis]

What are the odds of a single shot fired into the air randomly from a random location in California hitting someone?

Why just California? Weddings in Afghanistan could take down satellites too.

 

[dogjones]

And everyone else also. Good stuff

 

[spin0]

Bring on the fireworks and UFO-reports. UARS re-entry expected next Thu - Sat.

As of Sept. 18, 2011, the orbit of UARS was 133 mi by 149 mi (215 km by 240 km).
Re-entry is expected Sept. 23, plus or minus a day.
http://www.nasa.gov/mission_pages/uars/index.html

 

[jadebox]

In 1978 the soviets had a bad launch of Cosmos 954, a military surveillance satellite intended to track US submarines. The satellite failed to reach proper orbit and soon afterward came down over northern Alberta, Saskatchewan and the Northwest Territory in Canada.

I gave James Randi a book I found that was about the search for that satellite. I gave the book to him because his buddy, Earl Curley, is mentioned on one page. Curley often cited the book as evidence of his psychic powers. The author of the book actually treated Curley as a silly footnote - "oh, by the way, this psychic showed up claiming to now where the satellite landed."

-- Roger

 

[jadebox]

I don't recall anyone mentioning it, but the actual odds that any one specific individual will be hit are about 1 in 22 trillion (7 billion times 3200).

But, that doesn't stop several web sites from reporting that there's a 1 in 3200 chance that "you will be hit by a falling satellite." Some examples:

http://www.disinfo.com/2011/09/you-...ng-climate-change-study-satellite-this-month/

http://geektyrant.com/news/2011/9/1...g-hit-by-the-nasa-satellite-plus-equally.html

-- Roger

 

[dogjones]

Well, sure, but the odds of it hitting a human are still apparently 1 in 3200. Just because Fred Smith from Dorking has a one in 22 trillion chance of getting beaned doesn't mean the odds are acceptable.

 

[dasmiller]

Well, sure, but the odds of it hitting a human are still apparently 1 in 3200. Just because Fred Smith from Dorking has a one in 22 trillion chance of getting beaned doesn't mean the odds are acceptable.

That depends on how one feels about Mr. Smith. Now, I can't prove he's the one who called the cops on that fateful night that I stopped over in Dorking, but . . .

well, I've probably said too much already.

 

[jadebox]

Well, sure, but the odds of it hitting a human are still apparently 1 in 3200. Just because Fred Smith from Dorking has a one in 22 trillion chance of getting beaned doesn't mean the odds are acceptable.

I don't think anyone said they are acceptable - not even NASA.

http://www.nasa.gov/pdf/585584main_UARS_Status.pdf

-- Roger

 

[theprestige]

Well, sure, but the odds of it hitting a human are still apparently 1 in 3200. Just because Fred Smith from Dorking has a one in 22 trillion chance of getting beaned doesn't mean the odds are acceptable.

Assuming that pretty much every earth-to-orbit mission has a nonzero chance of smacking somebody upside the face with a chunk of launch vehicle or spacecraft, what would you say are the acceptable odds?