Tuesday, October 16, 2012

Chasing Mercury - The Northrop N-227




One of the requests that Diane made when I started doing monthly articles for her was to cover space related projects. This was because our sector includes the former TRW, which has an incredible space history.

Fortunately, I also had a strong interest in that subject, so the request was not a hard one to fulfill. I am, after all, a child of the space age. But I remain a heritage Northrop guy and even though I greatly appreciate the history of Grumman, Ryan, Radioplane, TRW and Scaled Composites, any chance I get to explore Northrop legacy programs and proposals I will do so in a heartbeat.

This is not to say I won't explore the other heritage companies' histories - I have and I will continue to do so and they will eventually be posted here. But availability is also a key and I have had much more success with finding Northrop history than with the other companies, save perhaps Ryan.

The Mercury Program is of special signifcance to me. I remember my mother waking me in the early morning to watch Alan Shepard's suborbital flight and later John Glenn's launch and three-orbits around the Earth. Nearly twenty years later the circle would close as I roused my six-year old daughter to watch Columbia make the maiden voyage of the shuttle program into space. Perhaps someday she can watch a launch to Mars with her kids in the wee hours of the morning.

One final note: I did manage to find some information on the Grumman G-214, their Mercury proposal. Be on the lookout for it in the next few days.

This article was originally published in the Northrop Grumman Engineering Department in-house, on-line magazine Airspace, vol. 2, no. 6, in April 2011. It is re-posted here with permission and has approved for public release case number 12-1474.      

Chasing Mercury – The Northrop N-227
By Tony Chong


April 12, 2011 marked the 50th anniversary of the launch of Vostok 1.  On that day in 1961 Soviet cosmonaut Yuri Gagarin became the first human to go into space.  He also became the first human to orbit the Earth.

Twenty-three days later, on May 5, 1961, Alan Shepard became the first American astronaut to go into space during a 15 minute, 28 second sub-orbital flight that took him 303 miles downrange from the launch site at Cape Canaveral, Florida.  Shepard rode inside a Mercury capsule fitted to a U.S. Army Redstone missile. 

Project Mercury, America’s first series of manned spacecraft, was a program designed to put an American into space as quickly as possible.  It was not, however, a hastily conceived stop-gap measure.  In actuality the ballistic manned satellite concept was one of three methods under active consideration by the U.S. Air Force since 1956 for establishing an American presence in space, with the initial phase eventually being called “Man In Space Soonest” and the fourth and last phase to encompass a manned lunar landing fifteen years after program start. 

Sputnik’s launch on October 4, 1957 changed all of the dynamics in the blossoming American space program.  Faced with a need to respond to the Soviet initiative, and with a desire to curb military expansion into space, President Dwight Eisenhower threw his weight behind a civilian-controlled agency.  The important, but obscure National Advisory Committee for Aeronautics was remade into the National Aeronautics and Space Administration, effective October 1, 1958.

NACA had itself examined the three basic types of manned spacecraft – ballistic, skip and glide – prior to Sputnik.  For a variety of good reasons (launcher capabilities and developmental issues, among others), the new NASA chose the ballistic approach.  McDonnell Aircraft Corporation won the competition to build the capsule, but what is largely forgotten is that heritage Northrop Aircraft, Inc. competed for that program as well.

Northrop was one of the eleven aircraft manufacturers that responded to the Air Force’s 1956 request to industry for manned satellite concepts.  As late as January 1958 the company (which changed its name to Northrop Corporation on February 2, 1959) adhered to the more sophisticated “boost-glide” vehicle proposal, the basis for the eventual X-20 Dyna-Soar (Dynamic Soarer) program won by Boeing in June 1959.  However, with NASA issuing a specification on November 14, 1958, for a ballistic capsule, Northrop answered with a design that carried the internal designation N-227.

NASA’s specifications included the need to fit the capsule to both the Redstone missile (for sub-orbital flights) and the Air Force/Convair Astronautics Atlas missile (for orbital missions).  Additional requirements for a launch-escape rocket tower system, a retro-rocket system for de-orbiting, a zero-lift body utilizing blunt-end re-entry for drag braking, pilot controllability of the capsule and the ability to land in water also drove the basic shape of the design.

Northrop’s proposal was very similar to the winning McDonnell vehicle.  The main visual differences were in the wider diameter at the blunt end for the Northrop craft – 80 inches versus McDonnell’s 74.5 inches – and the shape of the forebody of the capsule. 

The launch-escape rocket tower structure also differed in where it attached to the two proposals.  Northrop’s craft featured a constant-diameter forebody with the tower joined to the flat end (top) of the vehicle.  McDonnell’s design had a tiered forebody with the tower structure fitted over the smaller diameter upper section.

Both designs also featured a corrugated look to the capsule exterior surface.  However, Northrop’s corrugations ran along the length of the vehicle while McDonnell’s formed around the circumference of the craft.

Final designs on this fast-tracked proposal were due by December 11, 1958.  The NASA selection team worked over the Christmas holidays to determine the winner.  Northrop did not make the final cut. 

Ironically, heritage Grumman, a late entry into the manned spaceflight game, did.  It essentially tied with McDonnell as having the best design.  However, because Grumman was deemed to be short on manpower due to some impending Navy contracts, the award was given to McDonnell on January 12, 1959. 

Alan Shepard would make his historic flight just two years and four months later.

 

Kristi Harding of Records Management contributed to this article.

Any information on the Grumman Mercury proposal would be greatly appreciated by the author for incorporation in a possible future article.


For further reading, check out “This New Ocean – A History of Project Mercury” by Swenson, Grimwood and Alexander, NASA SP-4201 in the NASA Historical Series, U.S. Government Printing Office, 1966.

For “Man-In-Space-Soonest” background information, check out: http://www.astronautix.com/fam/manonest.htm


Tony Chong is a historian, photographer and a contributing editor to Airspace. He leads activities in the Aerospace Systems Display Model Shop and works in El Segundo.
 

Photo Captions

 

1) N-227 3-view: This 3-view drawing taken from the Northrop proposal shows the basic layout of the N-227 design.  Note the shape of the forebody, the attachment of the launch-escape rocket tower and the diameter of the blunt end of the spacecraft.  The head-on view shows the linear corrugations on the skin.  Photo credit: Tony Chong collection 

 
2) McDonnell 3-view: By comparison this general arrangement 3-view drawing of the McDonnell capsule, taken from one of its proposal pages, shows a tiered forebody, a narrower diameter in the widest part of the capsule proper (the adapter shroud flares out more) and a different method of attaching the tower structure to the spacecraft.  Photo credit: Tony Chong collection 

 
3) N-227 stats: Another page from the Northrop proposal features a weights and balance breakdown of the various components of the company’s design.  Photo credit: Tony Chong collection

 
4) img066: Northrop’s proposal featured an artist’s concept painting of the N-227 in the splashdown/recovery phase.  The linear corrugations show up well in this interpretation, as does the inflated orange, torus-shaped landing impact airbag with an internally-fitted stabilization water bag.  The artist’s signature says “Todd.”  Photo credit: Tony Chong collection

 
5) 158209: Several photos were taken of a small model of the N-227 showing how it would have looked mounted on a Redstone or Atlas missile.  This particular image shows the rather ungainly looking transition fairing and how it would have joined to the Redstone missile.  Photo credit: Northrop Grumman

6) mr-2: Contrast the previous image with this of the McDonnell Mercury capsule fitted to the Redstone missile.  Even with the slight overhang, the smaller diameter of the McDonnell design makes for a much cleaner fit to the launcher.  Photo credit: NASA 

7) 158208: This image shows the model of the N-227 separated from the Redstone launcher.  The combined fairing, capsule and launch-escape rocket tower assembly sitting next to the Redstone body gives a good indication of the relatively small size of the missile, as if emphasizing that it was only powerful enough for sub-orbital flights.  Photo credit: Northrop Grumman

 
8) 158206: The fairing on the N-227 and how it joins to the Atlas missile is shown in this photo.  Note the inverse taper from the capsule’s 80” diameter body to the smaller diameter top of the Atlas.  Photo credit: Northrop Grumman

9) GPN-2003-00042w: Again, the contrast between the Northrop proposal and the actual Mercury/Atlas combination is noticeable.  While still featuring an inverse taper, the McDonnell fairing is much shorter than the N-227’s.  An obvious question would be did the taller fairing and wider capsule, with perhaps its potential vibration and/or stability problems along the transition structure, play a part in Northrop’s loss?  Photo credit: NASA

10) 158207: The N-227, with its tower and fairing, is shown separated from the Atlas booster.  The hand is a good indicator of the size and scale of the model.  Photo credit: Northrop Grumman

3 comments:

  1. ...Outstanding work, Tony! On a side note, the comments about the adapters does beg the question: who was/would have been responsible for the final design and construction of those adapter(s)? The spacecraft manufacturer, or the booster manufacturer?

    ReplyDelete
    Replies
    1. In the case of the Mercury Program it was McDonnell that developed the adapter. It appears McDonnell may have subcontracted out the adapter on the Gemini Program, but I am not certain of that. I have not delved into the Apollo Program yet, so I can't answer for that case. Based on this I would assume Northrop would have been responsible for the adapter on their Mercury version.

      Delete