Author Topic: The Atlas and the Flight of Friendship 7  (Read 3179 times)

Online AS-503

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The Atlas and the Flight of Friendship 7
« on: 11/19/2010 06:34 am »
I have been learning about the Atlas ICBM development and would like to make some comments about the information that I have read in the hopes that many of you on this forum can add to it.

I also have some questions about the Mercury Atlas with John Glenn’s flight in particular (the first manned Atlas flight, first American orbital flight).

I hope the bullet points are okay. Please correct where wrong or add details as necessary. Vehicle development is fascinating, particularly when most of the advances listed here were bleeding edge.

Convair structures engineer Charlie Bossart examines the V-2 in 1947 and notes the heavy, non efficient design of separate skin and tankage. Comes to the conclusion of making the thin steel balloon tanks that would be used on the Atlas.

While in development in the early 1950’s the unknown weight of the thermo-nuclear warhead is causing uncertainty about required lift off thrust and vehicle specifications.

Change in funding from the White House to “National Priority”, which also sees two new IRBMs; (Thor) and Von Braun’s ABMA (Jupiter).

Original propellant choice is fluorine/ammonia. A spill and the resulting cloud near Canoga Park forces a rethink to JP-4/LOX.

REAP (rocket engine advancement program) develops RP-1 which is immediately tested and adopted.
Gimbaled engines, Thor's use of turbine exhaust for roll control and tubular walled bell shaped nozzles all come from REAP.

Engineers were hand drawing shock wave patterns to optimize nozzle shapes and lengths until a guy named G.V.R. Rao used mainframe computers to tackle this problem.

Rocketdyne pioneered the brazing oven process for tubular nozzle and thrust chamber manufacturing. Prior to this they had been hand brazing nozzles.

First flight in June of 1957 ended with vehicle tumbling end over end with termination by range safety officer. This was significant in two important areas. First, engineers doubtful of the balloon tank structural strength we stunned that the vehicle stayed together. Second, recirculation of hot gasses had fried crucial components in the boat tail section (Ares V/RS-68?).

The last major hurdle was combustion instability caused by the flat injector. Engineers solved this by using the baffled injector face.


Now for my questions about John Glenn’s Mercury Atlas.

I have read that as much as 1 in 5 (or higher) Atlas’ were suffering from launch failure due to combustion instability. Rocketdyne had solved the problem with the baffled injector face but NASA refused to fly the new “untested” design. If this is true then Mercury/Friendship 7 flew with a high probability of failure. Any comments?

Was Frienship 7 the last Atlas flight without the baffled injector?

Bob Gilruth and Max Faget (Space Task Group) had told the Air Force that they thought the Mercury/Atlas test flight failures were due to the balloon tank walls being too thin for the Mercury capsule. They suggested that the technicians install a “belly band” to structurally strengthen the tissue thin stainless steel wall of the Atlas ICBM.

This “belly band” did fix the problem. My question is, where exactly did they install this “hose clamp”? Was it around the tapered section near the Mercury capsule or was it lower on the more constant diameter section of the booster? One book I have states that it was at the point where the capsule meets (interfaces with) the booster.

Was John Glenn’s flight the only Mercury Atlas to fly with the thinner walled tanks? If so would that make Friendship 7 the only Mercury/Atlas flight with the belly bands?   

Sorry for the long post, I hope that you guys can shed some light on these questions.

Offline Jim

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Re: The Atlas and the Flight of Friendship 7
« Reply #1 on: 11/19/2010 11:34 am »

1.  Thor's use of turbine exhaust for roll control

2, This “belly band” did fix the problem. My question is, where exactly did they install this “hose clamp”? Was it around the tapered section near the Mercury capsule or was it lower on the more constant diameter section of the booster? One book I have states that it was at the point where the capsule meets (interfaces with) the booster.


1,  Thor used vernier thrusters for roll control like Atlas.  Jupiter used turbine exhaust.

2. Gilruth and Faget made no such suggestion. 
MA-1 (Atlas 50D) had a structural failure at the launch vehicle/spacecraft adapter interface.
MA-2 (Atlas 67D) had a belly band to strengthen this area on the Atlas.
MA-3 (Atlas 100D) and subs had increased skin thickness in this area.  Glenn flew MA-6, 3 Atlases later.

http://history.nasa.gov/SP-4201/ch10-4.htm

Read this web book
« Last Edit: 11/19/2010 11:36 am by Jim »

Offline Art LeBrun

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Re: The Atlas and the Flight of Friendship 7
« Reply #2 on: 11/19/2010 12:04 pm »
The first MA Atlas with baffled injectors was 113D MA-8.

I am aware of two Atlas failures for combustion instability in March and April 1960 - 51D and 48D which were R&D missiles.

I assume this image of 67D shows the band applied at the interface of Atlas and Mercury adapter. It would seem the shape of the spacecraft caused buffeting. I am sure wind tunnel tests were made?

Integral tanks were first used with MX-774 (1948) and Viking (1949).

Gimbaled engine was used on Viking (1949).

Atlas base heating was solved by 1) insulation 2) shortening the boattail (nozzle exits further away) 3) using stainless steel tubing. Third Atlas flown had the changes Dec. 1957
« Last Edit: 11/22/2010 02:45 pm by Art LeBrun »
1958 launch vehicle highlights: Vanguard TV-4 and Atlas 12B

Online AS-503

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Re: The Atlas and the Flight of Friendship 7
« Reply #3 on: 11/19/2010 05:45 pm »

1.  Thor's use of turbine exhaust for roll control

2, This “belly band” did fix the problem. My question is, where exactly did they install this “hose clamp”? Was it around the tapered section near the Mercury capsule or was it lower on the more constant diameter section of the booster? One book I have states that it was at the point where the capsule meets (interfaces with) the booster.


1,  Thor used vernier thrusters for roll control like Atlas.  Jupiter used turbine exhaust.

2. Gilruth and Faget made no such suggestion. 
MA-1 (Atlas 50D) had a structural failure at the launch vehicle/spacecraft adapter interface.
MA-2 (Atlas 67D) had a belly band to strengthen this area on the Atlas.
MA-3 (Atlas 100D) and subs had increased skin thickness in this area.  Glenn flew MA-6, 3 Atlases later.

http://history.nasa.gov/SP-4201/ch10-4.htm

Read this web book


Thanks for the follow up Jim. This is the feedback I had hoped to get.


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