Previous Thread
Next Thread
Print Thread
#322323 - 02/04/09 10:30 AM Space Station Shaking  
Joined: Nov 2006
Posts: 1,094
Danny2 Offline
.
Danny2  Offline

But during the Jan. 14 firing, something went seriously awry. The station’s solar power wings began swaying back and forth alarmingly. More dramatically, an interior camera captured views of wall-mounted equipment and cables flopping back and forth to a two-second beat, as the camera itself swayed on its mounting bracket.

Buildup of gyrations
It was quickly apparent that some periodic force had excited the space station’s structure at one of its resonant frequencies, leading to a buildup of gyrations rather than a damping down. As with the traditional "soldiers marching across a bridge" story, and the all-too-real Tacoma Narrows bridge collapse in 1940, resonance buildup in a large structure can quickly lead to serious consequences.

Kelly Humphries, a spokesman at the Johnson Space Center in Houston, told msnbc.com in an e-mail that the space station’s structure “has been cleared for tomorrow's burn, but the burn has been canceled.” Other sources told msnbc.com that the clearance was granted only for use of the much gentler small engines on a docked Progress. Use of the larger engines, and their autopilot control software, remains suspended. The sources spoke on condition of anonymity because they were not authorized to discuss the limitation publicly.

Humphries said that the latest burn cancellation was a good idea for other reasons. “This will help us conserve propellant and set up better for the 2JA mission [a shuttle flight scheduled for launch on May 15], where we were trying to deal with too much altitude,” he wrote.

These are real benefits, sources told msnbc.com, but they would never have caused the cancellation of the burn if the original overshaking hadn’t occurred.

Delayed reports
The shaking was not discussed publicly when it happened, but 10 days afterward, the anomaly was described as “higher-than-usual structural oscillations” in one of NASA’s routine station status reports. The report said the next reboost would be put on "temporary hold until results ... have been reviewed in depth".


Slideshow
Planetary Nebula NGC 2818, Hubble Space Telescope

Month in Space
See the fireworks of a planetary nebula, a fresh crater on Mars and other cosmic highlights from January.

more photos
Two days later, another status report said the Russians determined that the shaking was brought on after “an error in parameter settings” was uploaded to the engine control system for the Zvezda module.

The Russian engines are hinge-mounted to allow a small variation in thrust pointing direction, and somehow the autopilot began swinging the engine up and down seeking the “sweet spot” for thrusting, but always overshooting and repeatedly reversing direction. By unfortunate coincidence, that back-and-forth swinging had a period close to the station’s resonant frequency. So, like a child pushing periodically on the back of her swing-mounted playmate, the swings became wilder and wilder.

How bad was the shaking?
The thrashing of the long solar array wings reached a degree "five times greater than allowed," one source told msnbc.com in an e-mail. Another source said the swaying was the "biggest I've ever seen... Outside the certified limits of ISS structure…"


#322431 - 02/04/09 05:49 PM Re: Space Station Shaking [Re: Danny2]  
Joined: Oct 2004
Posts: 3,881
reaper Offline
.
reaper  Offline
But are they still beaming signals to you????

#322444 - 02/04/09 06:14 PM Re: Space Station Shaking [Re: Danny2]  
Joined: Jul 2000
Posts: 1,925
papashine Offline
.
papashine  Offline
Whats a ISS???


Reality..What a concept!
#322446 - 02/04/09 06:17 PM Re: Space Station Shaking [Re: papashine]  
Joined: Aug 2008
Posts: 3,046
Peter Jones Offline
.
Peter Jones  Offline
International Space Station....?

#322448 - 02/04/09 06:20 PM Re: Space Station Shaking [Re: Peter Jones]  
Joined: Jul 2000
Posts: 1,925
papashine Offline
.
papashine  Offline
Thanks, its been quite a day for abreveations laugh


Reality..What a concept!
#322449 - 02/04/09 06:23 PM Re: Space Station Shaking [Re: papashine]  
Joined: Aug 2007
Posts: 3,157
pugwash Offline
pugwash  Offline
Danny...you have your own thread for this sort of thing now smile


It's rarely rocket science, it's usually just math: then again if you can't do the math.......
#322550 - 02/05/09 09:38 AM Re: Space Station Shaking [Re: pugwash]  
Joined: Nov 2006
Posts: 1,094
Danny2 Offline
.
Danny2  Offline

Pug, now you passing out threads. If you are your passing them out of your a$$.


Links
Portofino Resort- Now with a new BEACH BAR!!

Click for excellent scuba lessons with Elbert Greer!


Things to do

News
Daily News
Daily Weather

Classified Ads
BelizeNews.com
San Pedro Sun
Ambergris Today
SP Town Council
Channel 7
Channel 5
Amandala
Love FM
The Reporter
PLUS TV
TV Newscasts
Radio Stations

Click for our
Search thousands of Belizean-only websites

Event Guides
Event Calendar
Specials & Events
Things to Do
SanPedroScoop
iTravel Belize
Paradise Theater

Blogs
San Pedro Scoop!
Tia Chocolate
Tacogirl
My Beautiful Belize
I-Travel Belize
Belize Adventure
Belize Hub
Romantic Travel
Bound for Belize
Conch Creative
As The Coconuts Drop
More Blogs...
Search thousands of Belizean-only websites
Chaa Creek is an award-winning luxury Belize Resort, rated as one of the worlds best Eco Lodges. We are a pioneer in adventure travel to Belize since 1981!
White Sands Dive Shop - 5 Star PADI Dive Facility - Daily diving, SCUBA instruction and Snorkeling
Caribbean Inspired All Natural Condiments & Spice Blends, Over 100 are Gluten Free!
We manage a variety of homes, apartments, condos and commercial properties here on Ambergris Caye. Our minimum lease on ALL properties is six months.
Conch Shell Inn: All rooms are right on the beach in the heart of San Pedro, so within walking distance to anything and everything!!
Lil Alphonse has snorkel equipment to fit anyone as well as Marine Park Tickets and flotation devices to assist those not as experienced.
Coastal Xpress offers a daily scheduled ferry run to most resorts, restaurants and private piers on the island of Anbergris Caye. We also offer  private and charter water taxi service.
June
S M T W T F S
1 2 3
4 5 6 7 8 9 10
11 12 13 14 15 16 17
18 19 20 21 22 23 24
25 26 27 28 29 30
Cayo Espanto
Click for Cayo Espanto, and have your own private island
More Links
Click for exciting and adventurous tours of Belize with Katie Valk!
Mini Chat
Who's Online Now
1 registered members (1 invisible), 118 guests, and 13 spiders.
Key: Admin, Global Mod, Mod
Forum Statistics
Forums44
Topics64,656
Posts463,669
Members18,834
Most Online1,262
Jun 10th, 2007



AmbergrisCaye.com CayeCaulker.org HELP! Visitor Center Goods & Services San Pedro Town
BelizeSearch.com Message Board Lodging Diving Fishing Things to Do History
BelizeNews.com Maps Phonebook Belize Business Directory
BelizeCards.com Picture of the Day

The opinions and views expressed on this board are the subjective opinions of Ambergris Caye Message Board members
and not of the Ambergris Caye Message Board its affiliates, or its employees.

Powered by UBB.threads™ PHP Forum Software 7.6.0