EagleRJ
Are we there yet?
- Joined
- Nov 27, 2001
- Posts
- 1,490
I'm glad I'm not the NASA weenie who had to explain the concept of turbopumps to the media!
I actually think it's not a good idea to press ahead and launch tomorrow without resolving this problem.
Here's the issue:
The sensors that have been malfunctioning are not used in a normal launch- in fact they have not been used in any launch. They are intended to shut the engines down should fuel run out prematurely, to prevent the engines from doing all kinds of dramatic things. During a normal launch, the External Tank contains more fuel than the launch profile requires, even after accounting for boil-off. Should the hydrogen tank run dry due to a leak or something, the sensors would shut the engines down before the turbopumps start gulping air.
The problem is that the sensors in question have intermittantly been showing a "false empty" reading. That would create a major problem if they were to indicate empty during the ascent. The Shuttle has numerous abort scenarios for the loss of one or two main engines, but there is a long period of time when it couldn't handle the loss of all three SSMEs, since it has too much energy to return to Florida and too little energy to reach the abort sites in Europe.
Hopefully the NASA engineers are able to insert some software code that will cause the engine computers to ignore the sensors until the Shuttle is in range of Europe. I hope they did something like that, and we're not just "crossing our fingers" here.
I actually think it's not a good idea to press ahead and launch tomorrow without resolving this problem.
Here's the issue:
The sensors that have been malfunctioning are not used in a normal launch- in fact they have not been used in any launch. They are intended to shut the engines down should fuel run out prematurely, to prevent the engines from doing all kinds of dramatic things. During a normal launch, the External Tank contains more fuel than the launch profile requires, even after accounting for boil-off. Should the hydrogen tank run dry due to a leak or something, the sensors would shut the engines down before the turbopumps start gulping air.
The problem is that the sensors in question have intermittantly been showing a "false empty" reading. That would create a major problem if they were to indicate empty during the ascent. The Shuttle has numerous abort scenarios for the loss of one or two main engines, but there is a long period of time when it couldn't handle the loss of all three SSMEs, since it has too much energy to return to Florida and too little energy to reach the abort sites in Europe.
Hopefully the NASA engineers are able to insert some software code that will cause the engine computers to ignore the sensors until the Shuttle is in range of Europe. I hope they did something like that, and we're not just "crossing our fingers" here.