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T-43 Hours and Counting
An anonymous reader submits "As seen on NASA TV, for the first time in over two years, the countdown clock has started at 6:00 PM EDT for the Wednesday 3:51 PM EDT launch of Space Shuttle Discovery on the first of the return to flight test flights. The launch is not for certain due to weather issues associated with hurricane Dennis. Currently it is estimated for a 70% chance of launch on Wednesday, with the chances lowering later in the week. If you are confused on how T-43 hours equals almost 3 days, perhaps you should read Countdown 101."
NASA TV certainly has come a long way since the days of CUSeeMe rooms. Anyone remember those?
T is simply an arbitrary fixed timescale for the launch, it could easily be "a, b, c" etc but it provides a time frame for how long certain activities ought to take.
Time. As in liftoff time. Before the liftoff, the clock regesters as "T minus ..." after liftoff it regesters as "T plus..."
Linkeh.
Information about tuning in to NASA TV can be found here as well.
Your hair look like poop, Bob! - Wanker.
It makes more sense if you say the whole phrase:
T minus 43 hours = launch time minus 43 hours
Basically, its come to somewhere nearby, and watch. If you dont want to spend a whole lot of time or money, i suggest Titusville (where I live) This place is right across the Indian River Lagoon from the Island NASA is on. There are many parks, and space-related memorial sites to view the launch from. While you're here, you can also visit the Space Museum, and take a trip out to the KSC Visitor's Center for a day. 73 DE KI4GMB
There's a tropical system currently at about 42W and south of 18N that some of the models forecast to be a threat to Florida later this week.
Specifically, the Canadian models have it crossing Florida from the Atlantic side and going into the Gulf.
To have ambition was my ambition.
As others have said, T = Time. Note that they typically only use T if they are counting in hours or less. If we're talking days, it is typically D-3 = 3 days before. That is where D-Day comes from.
Kjella
Live today, because you never know what tomorrow brings
Here at Cape Canaveral there are several letters that get used. L (only for minus count, up till coming out of the final hold point) is the actual time till planned launch time. L of course for launch. R has also been used for days prior to launch for Titans. All of these times are based on preparation actions. Some are based on time before launch. Some, you don't want to accomplish until you get past a milestone, which are what the built-in holds, and holdpoints are there for.
Our founding fathers removed the guys in charge. Be American. Vote incumbents out.
lol...
Umbilicals provide power and such to the shuttle while it is on the pad. The shuttle's batteries/fuel cells provide enough power for the mission, but they like to run it on Earth-based power for as long as possible before setting it on its own power.
Just think of "Demate the orbiter's midbody umbilical unit" as "Unplug laptop" before taking it off your desk. I know, not so sexy, but just imagine the laptop is a Powerbook G5 or an Alienware Media Center laptop that is liquid cooled, overclocked, and only 1" thin/5 lbs., whichever daydream is your preference.
Here's a quick nitpick about the linked Countdown 101 from the summary - the clock in the picture reads +00:00:05, yet the caption says it was taken "before a Space Shuttle launch."
:)
I enjoy bloopers, and hopefully somebody else will too.
if you'd like to see the launch from the ground, get here a couple hours ahead... i suggest stopping at my workplace (Krystal) and grabbing some burgers to whittle the time away. If you go to the right place, there might even be someone with a direct link to the count down. Hope to see you, and good luck! 73 DE KI4GMB
"Demate" is just cable-speak for unplug. Parent describes umbilicals well, with one caveat:
It's not only that they prefer to run on Earth-based power for as long as possible (which is true) - they have to. They use thermal batteries in additional to rechargeable NiCd batteries which, once squibbed (told to turn on), 'fire' until they completely discharge.
Did you make that up? Every landing in WWII had a D-Day and an H-Hour. North Africa, Sicily, Italy, every one of those Pacific islands ... it's just a designation for the actual day of the attack. Nothing to do with coding different dates as different letters.
You know that someone has either done too much cociane, is stupid, or has read too much Rand when they try to apply a theory made up in an ideal situation to a real world on going issue. Challenger was caused by an Senile republican, and Columbia was caused by multiple failures and basic design flaws. Neither of these were distance related.
First, we do not live in a world where distance matters. Even in 1960 distance did not matter that much. Yes JSC is in houston becuase of LBJ, but if it weren't in houston, it would be somewhere else nearly equally far away.
I can generally tell that people are clueless about spaceflight, and real world events in general, when they complain about the locations of the space centers. KSC is where it is because it is the most southern part of the US. This allows us to save a bit of fuel on launch. It is not a good location for many other things due it exposure to threats, both natural and man made. If everything was in one place, a single bomb could take out everything. JSC is stout set of buidling that can work even in dangerous weather.
Furthermore, no practical politician is going to build that much money into one location. It would make the economy too dependent on the government teat. Just look at the communities that have dependencies on the dole created by the military bases.
And, as mentioned, distance is not that much of an issues. Even in the 60's we had these high tech things called telephones and aeroplanes. This allowed us to have the launch facilities in a very good location, and mission control in much more protected locations, and other centers in other locations to maximize the availablity of resources.
It is not the ideal solution, but no real world solution is. It is better than some commercial solutions, which carry the launch vehicle to sea, or launch from the texas desert, which means that we are going to have a fully fueled aircraft exploding, dropping burning peices and combustables from Dallas to Atlanta, instead of over the ocean.
As I have mentioned before, the private commercial sector has done little more that the Soviets did over 40 years ago. While your points are somewhat valid, they hav not produced an infrasture to send people to space, merely LEO, which can really be done with a hot air ballon.
I believe that the private sector can do, and will do it, in the next 10 years. But look at the ineffeciencies and waste in any large corporations. It matches or exceed governments. The same will be true for space travel.
And, btw, without government handouts we would have very little industry. Some of these handouts lasted a long time. The government funding of the taking of land from the native americans, and the giving of land to the new immigrants. The government handout of land to the railroads. The government handout of spectrum. The government support of the early airlines through the air mail. NASA is a government handout, one that is going to pay off when the private sector gets off it's ass and startes investing. Now, thanks to the dot com bubble, there is enough money to so do.
"She's a scientist and a lesbian. She's not going to let it slide." Orphan Black
T- stands for "Time minus". "Time" is when the main event occurs (the shuttle liftoff). All other times are specified as relative to this event. Thus, T minus 3 minutes is (theoretically) three minutes before the shuttle lifts off, and T plus 6 hours is 6 hours after the shuttle lifts off. The military uses this convention for operations too (e.g. D-Day plus 6 is 6 days after D-Day). This system is good because it allows things to be scheduled without knowing exactly when the main event is going to occur (the launch could be delayed by weather, etc).
The system isn't perfect though, which is why you have "holds" for some things. These "holds" allow time for activities whose duration is really difficult to predict.
T stands for "Time Until Launch". Check out http://space.launch.info/countdown.html for a nice overview about a launch countdown.
Actually I worked with a bunch of meteorologists.
Anytime you see "70% chance of rain" it means that of all the noted times that similar weather conditions occurred, 70% of those times the weather conditions resulted in rain.
"It's a very tangled subsystem." --Windows kernel guru