LIVE: SpaceX - Falcon I (Mk.II) NET March 20 (Attempt 2)

[Jim]

Where was the TDRSS telemetry that was to be tested on this flight

[Thomas ESA]

To be clear, how did Orbital's first Pegasus perform and was this new technology as much as Falcon I at debut launch?

[Jim]

Thomas ESA - 21/3/2007  11:37 AM

To be clear, how did Orbital's first Pegasus perform and was this new technology as much as Falcon I at debut launch?

More

3 new solids
air dropped launch vehicle
Aerodynamic pull up
Mil std bus based avionics

I believe laser ring gyros
smaller launch crew

Aero will add more or correct me

[bigdog]

Jim - 21/3/2007  9:30 AM

bigdog - 21/3/2007  11:09 AM

1.  That they actually were allowed to recycle after an engine start is very impressive.  I doubt the East or West Coast Rage would allow that at the Cape or VAFB.  Having done so will give SpaceX good ammunition to convice them otherwise, will interesting to see how it develops.

2.  I wonder if the Range from Kwaj still had the ability to terminate the flight at that point.  It would have only been for engine cutoff and they would have commaneded it if the vehicle got out of it's flight path window.  E&W Ranges have the ability to destroy the second stage on other vehicles through a fairly long part of ss flight on other launchers.

1.  Not a range call.  Range has no say in mission success.

2.  It was still insight of the island so I would say yes

1. I was not thinking of it in terms of mission success but yes that is true.  I just thought that they (E/W Range) may be concerned of a shutdown right after liftoff e.g. Sealaunch, and therefore not give a second go to launch.  I don't know if they would have to justify a no go and therefore keep it on the ground for something not exactly under their control.

2. That's what I was thinking and did the engine shut down from the affects of the lost control or a range command.

[Jim]

still not a range call.   But a "real" customer on top would not have concurred with another attempt.

[hektor]

1) watching the video, I have the impression that the launch is very "vertical", like a sounding rocket
2) any news about the first stage retrieval ?

[Danderman]

hektor - 21/3/2007  8:50 AM  1) watching the video, I have the impression that the launch is very "vertical", like a sounding rocket

You are the second person here to comment on that. So, what do the experts say, was that "vertical" looking trajectory appropriate, or was something funky going on?

 

[hektor]

Since I haven't seen their nominal ascent profile, I can't say. All I can say is that they seem to gain a lot of altitude before going horizontal, compared to your usual Delta II.

[aero313]

Thomas ESA - 21/3/2007  11:37 AM

To be clear, how did Orbital's first Pegasus perform and was this new technology as much as Falcon I at debut launch?

First Pegasus was 100% successful - meaning the customer satellite WAS delivered to orbit.  Not sure how you rate "new technology".  If your goal is to design a truck to deliver packages, is it more important to use "new technology" or to deliver the package within cost and schedule?  More to the point, Pegasus used three brand new solid rocket motors that did not push the state of the art.  The avionics used an existing IMU and flight computer, but everything else was new.  SpaceX used a similar design approach.  Despite what their marketing materials say, Falcon 1 really isn't using any technology that hasn't flown before on other vehicles.

[aero313]

Jim - 21/3/2007  11:44 AM

Thomas ESA - 21/3/2007  11:37 AM

To be clear, how did Orbital's first Pegasus perform and was this new technology as much as Falcon I at debut launch?

More

3 new solids
air dropped launch vehicle
Aerodynamic pull up
Mil std bus based avionics

I believe laser ring gyros
smaller launch crew

Aero will add more or correct me

Correct except for the ring laser gyro.  LR-81 iron gyro was used originally.

[bigdog]

Danderman - 21/3/2007  9:53 AM

hektor - 21/3/2007  8:50 AM  1) watching the video, I have the impression that the launch is very "vertical", like a sounding rocket

You are the second person here to comment on that. So, what do the experts say, was that "vertical" looking trajectory appropriate, or was something funky going on?

 

Not talking as an expert but likely normal.  Look at past D4 Medium or A5 40x.  They need to get enough speed before heading down range.

[Ducati94]

Off the cuff; the 90% of the risk statement, I think is optimistic. I would really like to see a risk matrix that would prove me wrong.

[Bill White]

lmike - 21/3/2007  8:40 AM

Just to make sure I'm not (seemingly continuously;) ) misunderstood here, I do want SpaceX (Not Only!, and other 'alt.space' outfits to compete, I want real competition!!!  If SpaceX becomes just another conglomerate, it'd be of no use) companies to succeed.  Investment opportunities would be better for all of us.

To clarify, lmike, I meant Elon Musk's comments about being honest with investors ("no prudent investor would invest in SpaceX, therefore I'm keeping the company private") and I did not intend to criticize your comments.

In retrospect I see that you could have thought I was talking about your comments. My bad, Sorry.

Musk is famous for saying that "the best way to make a small fortune in the launch business is to start with a large one." At least he is honest.

[nacnud]

As to the launch profile; looking down a slope is deceptive, it often looks steeper looking down than it does looking up.

[spacedreams]

Has anybody heard if they know where the second stage ended up?

[clongton]

aero313 - 21/3/2007  11:56 AM
 Despite what their marketing materials say, Falcon 1 really isn't using any technology that hasn't flown before on other vehicles.

The Merlin and Kestrel engines are brand new in-house designs, so your statement may be a little misleading. While true that no "new technology" was employed, the Merlin is a brand new engine and it appears to have functioned flawlessly. Kestrel, the 2nd stage engine, also appears to have functioned flawlessly. Neither engine suffered any anomolies. The avionics shut down Kestrel prior to orbital insertion because the 2nd stage roll control wasn't functioning properly. Despite failure to reach orbit, the fact that the avionics understood the roll problem and shut down the engine is testament to excelence.

It's not the existing technology that was used to create these engines that makes them so impressive. It's the way the technology was combined and used. From the web site:

The main engine, called Merlin, was developed internally at SpaceX, but draws upon a long heritage of space proven engines. The pintle style injector at the heart of Merlin was first used in the Apollo Moon program for the lunar module landing engine, one of the most critical phases of the mission.

Propellant is fed via a single shaft, dual impeller turbo-pump operating on a gas generator cycle. The turbo-pump also provides the high pressure kerosene for the hydraulic actuators, which then recycles into the low pressure inlet. This eliminates the need for a separate hydraulic power system and means that thrust vector control failure by running out of hydraulic fluid is not possible. A third use of the turbo-pump is to provide roll control by actuating the turbine exhaust nozzle.

Combining the above three functions into one device that we know is functioning before the vehicle is allowed to lift off means a significant improvement in system level reliability.
Kestrel, also built around the pintle architecture, is designed to be a high efficiency, low pressure vacuum engine. It does not have a turbo-pump and is fed only by tank pressure.
Kestrel is ablatively cooled in the chamber and throat and radiatively cooled in the nozzle, which is fabricated from a high strength niobium alloy. As a metal, niobium is highly resistant to cracking compared to carbon-carbon. An impact from orbital debris or during stage separation would simply dent the metal, but have no meaningful effect on engine performance. Helium pressurant efficiency is substantially increased via a titanium heat exchanger on the ablative/niobium boundary.

Thrust vector control is provided by electro-mechanical actuators on the engine dome for pitch and yaw. Roll control (and attitude control during coast phases) is provided by helium cold gas thrusters.

A highly reliable and proven TEA-TEB pyrophoric system is used to provide multiple restart capability on the upper stage.  In a multi-manifested mission, this allows for drop off at different altitudes and inclinations.

BTW, does anyone know of any other rocket engine besides Kestrel which uses niobium alloy for the nozzle?

Falcon is not a Delta or an Atlas (yet), but it's damn impressive, especially coming from private pockets.

[josh_simonson]

Here's my theory on the failure:      Elon kept talking about roll and roll control, conjecturing about the cold gas thrusters or a leak. If one of those locked on, the others would have to fire to compensate - perhaps the deteriorating situation we saw was those other thrusters running out of propellant trying to maintain attitude - the wobble of the main engine may have been it's attempt to maintain course with all the roll control shenanigans going on. They probably already had a crude idea of what happened last night when they mentioned roll control problems, so it's likely to be pretty close to what Elon hinted at.  

 

It could be that the bump at separation was as innocuous as the thermal blanket on the first launch appearantly was.  

 

I had trouble feeling disapointed last night too, this was probably the most entertaining launch I've ever watched - with pad sound it could win an emmy.    The only things they didn't get to test was payload sep and second stage restart, so they got a pretty good look at nearly all the systems on this flight.

[gordo]

There will be more TV, but I suspect we will not get to see it.  The thing did a 360 and TV was rock solid, so it will still be there unless it went bang

[Danderman]

What is the benefit of the avionics shutting down the second stage engine if there is too much roll? I recall early launches where there was really significant roll, but this was dampened out, and the vehicle went on to orbit.

[Danderman]

gordo - 21/3/2007  10:53 AM  There will be more TV, but I suspect we will not get to see it.  The thing did a 360 and TV was rock solid, so it will still be there unless it went bang

It is not clear what you mean - how do you know that the thing did a 360?