Orion Launch Today

[Eric Mc]

With the launch of the first Orion space vehicle in a few hours time, I thought that it deserved a thread with a title that showed that the programme had progressed quite a bit since the original Orion thread was posted up.

If mods want to close this thread that's fine but I think the original title is not really immediate enough for today's events.

Launch is scheduled for 12.05 pm (just after mid-day) UK time.

I'm getting quite excited by this.

[Eric Mc]

Thanks for the alternative link. Spaceflight now seems to have gone off the air for the moment.

[Eric Mc]

MrRee145 said:

All Green so far for an on time launch. anyone else excited about this launch?

Naturally.

[Eric Mc]

Over 200 feet tall so 2/3 the height of a Saturn V. The Shuttle was about 100 feet tall.

The Delta IV Heavy develops 2 million pounds of thrust on lift off.

For comparison, the Shuttle was 6 million pounds and the Saturn V was 7.5 million pounds. The Saturn 1B was 1.5 million pounds.

[Eric Mc]

Yes - the five F1 engines pumped out 1.5 million pounds of thrust each. They ran on kerosene and liquid oxygen.

To put that in context, each F1 engine delivered the same thrust as the THREE main engines of the Space Shuttle

[Eric Mc]

All launch directors polled and a "Go" for launch has been received.

[Eric Mc]

Oops - ground wind violation.

[Eric Mc]

They just had a "Red Light" appear on one of their warning systems but now it seems to have cleared.

Still have an "RCO Hold".

This is bloody tense stuff.

[Eric Mc]

Bisonhead said:

When is the projected launch date for a manned mission? I seem to remember 2030 or so...

Earlier than that. 2020 was what I heard at the NASA press conference last night.

It is purely down to budgetary constraints. They just can't push ahead as fast as they would like to.

[Eric Mc]

MrRee145 said:

My feed as frozen do we have a new launch time yet or still held?

Looks like Spaceflight Now has crashed. I'm still watching on -

http://www.ustream.tv/nasahdtv/theater

[Eric Mc]

12.55 pm new launch time.

[Eric Mc]

LordGrover said:

Funny that the extremes of speed, temperature, and other forces this is to endure, it's halted a by a bit of a breeze on the ground.

Rockets are very vulnerable to sideways gusts during the first 3 to 5 minutes of launch. After about 5 minutes they have reached an altitude where the atmosphere has thinned sufficiently to not really be an issue anymore.

[Eric Mc]

Bisonhead said:

What about winds in the upper atmosphere? I thought they were frequently in the region of 60-70 mph?

Atmosphere much thinner so less of a problem. But there are upper limits for high altitude winds too.

[Eric Mc]

Another abort.

[Eric Mc]

The wind is putting the wind up me.

[Eric Mc]

More the Launch Control people ( a different group based at the Cape) Mission Control is based at Houston, Texas. Mission Control tend to take over as soon as the rocket has cleared the launch tower - although I'm not sure at what point they get involved on this flight.

They are well used to such scenarios playing out. To launch a rocket safely a whole load of criteria have to be met and multiple holds or even scrubs are not unusual.

[Eric Mc]

rhysenna said:

Are they booster rockets on the side?

Yes - although they are essentially the same as the main "core" section of the rocket.

The Delta IV Heavy is powered by three R68 liquid hydrogen/oxygen engines. As a result, if and when this thing takes off, you will see that the plume from the exhausts is a lot cleaner than that from (say) the Space Shuttle, the boosters of which were Solid Fueled and left a dense, smokey (and pretty poisonous) trail.

[Eric Mc]

el stovey said:

Is this limiting wind a surface wind or winds higher up?

Looks like the surface wind is under 10 knots going by nearby airfields etc.

They have been referring to low altitude "gusts" which are exceeding the limits.

[Eric Mc]

rhysenna said:

What's the difference in weight between this and Saturn V?

The thrust of the two gives an indication of the weights they are having to lift.

The Delta IV Heavy produces around 2 million pounds of thrust on lift off.

The Saturn V produced 7.5 million pounds of thrust on lift off.

The Delta IV Heavy is currently the most powerful rocket available to the US. So far, most of its launches have been putting heavy Department of Defense payloads into low earth orbit.

[Eric Mc]

That's why they have multiple sensors.

Once a rocket launch has been put on hold, all sorts of niggly problems start raising their head as the fully fueled booster sits there cold soaking all that oxidant and propellant.