Sunday, September 23, 2012

Talons in Space: Northrop's N-205 Proposal




When I ran across this concept nearly twenty years ago I was utterly amazed and intrigued by the whole idea of using a modified T-38 to gain access to suborbital space. It really was a fun subject to research and write about. I hope you enjoy it.

This article was originally published in Airspace vol. 3 no. 19, June 2012. It is posted here with permission and has approved for public release case number 12-1467.



Talons in Space: Northrop’s N-205 Proposal
By Tony Chong

The launch of Sputnik by the Soviet Union on October 4, 1957 created a massive shift in America’s perception of itself and its technological prowess. The result of that shift was a period of intense competition between differing visions of what our response should be, with the ultimate winner charting the course of this nation’s programs and policies for years to come.

Many proposals, drafted in the period before the Soviet launch, were to fall victim to the rushing demands of the new space race and the growing tensions within the country and around the world.  Among these casualties was the U.S. Air Force’s ambitious goal for a manned spacecraft that was winged and reusable. 

Part of an overall plan for a permanent military presence in space, up to and including orbiting space stations and bases on the Moon,1the aerospace plane was envisioned not just as a research vehicle, but also as a rapid-response reconnaissance platform as well as a strategic weapons system that would be impossible to defend against and recallable if necessary.

Despite the clamor after Sputnik, the Air Force pressed ahead with its plans, requesting and receiving 9 submissions from 12 contractors for an aerospace plane in March 1958. Boeing and the team of Martin-Bell won the first down-select, with Boeing becoming the surprise final winner in June 1959. The initial Phase I vehicle became known as the X-20 Dyna-Soar (Dynamic Soarer).2

Heritage Northrop, its boost-glide proposal eliminated from the first round down-select competition, nevertheless saw an opportunity for itself with the new X-20. While the company’s fortunes were rejuvenated in October 1956 with the selection of the N-156T as the new supersonic trainer for the Air Force, Northrop sought to further secure the program by expanding the capabilities and role of its newly designated T-38 Talon.

On May 22, 1958, barely two months after the Dyna-Soar initial down-select, Northrop proposed an “Aerospace Trainer” variant of the Talon, reasoning that the Air Force would require a reliable, low-cost vehicle to teach student astronaut-pilots how to operate in the near-space environment.3

Given the in-house designation N-205, the projected vehicle required only about a 25% modification to the basic T-38A structure to make it capable of the proposed mission. Powered by three Rocketdyne AR-4 rocket motors in place of the two General Electric J85-GE-5 turbojets, the rockets would generate a total of 33,000 lbs. of sea-level thrust using a 90% hydrogen peroxide, 10% JP-5 jet fuel mixture. 

Designed to be vertically launched at an 80° angle of attack from a small rail-guided ground platform, the N-205 would reach Mach 3.2 during the 90 second burn to 90,000 feet and coast to an apogee of 200,000 feet in a ballistic trajectory before returning. Hydrogen peroxide-fueled reaction jet nozzles in the fuselage nose and wing tips provided space attitude control.

Reentering at Mach 2.6 during the downward flight, the N-205 would then flatten out into a glide-slope angle at Mach 1.26 before coming in for a runway landing at a slightly higher touch-down speed than a standard T-38A. There was also an option for an “auxiliary” 1,000 lb. thrust rocket motor for added safety during the landing phase.

Unfortunately for Northrop, the Air Force took no action at this point, despite a subsequent study issued by the company on August 28, 1959 that again touted the advantages of an aerospace trainer.

In 1963 the company formally revised and readdressed the issue. By this time, in conjunction with the Navy and NASA, the Air Force was heavily involved in a winged aerospace plane flight research program with the North American X-15. X-20 development was also progressing, although the multiple changes in configuration and proposed launch platforms created a lot of vacillating requirements within the project.

A further impetus to Northrop’s action was the decision by the Air Force’s Experimental Flight Test Pilot School at Edwards Air Force Base to rename itself the Aerospace Research Pilot School (ARPS) on October 12, 1961. Utilizing their existing fleet of Lockheed F-104 Starfighters, the school pressed for converting several of the aircraft into aerospace trainers.  The resulting vehicle, designated the NF-104A, was outfitted with an additional engine, a Rocketdyne AR2-3 rocket motor, at the base of the vertical tail which made the aircraft capable of ballistic trajectories up to 120,000 feet.

On April 29, 1963, three months before the NF-104A began contractor flight trials, Northrop presented a new report titled “ST-38 Aerospace Trainer Study.4” Also known as the N-205B the ST-38 featured many improvements in performance over the original proposal.

Chief among these was the elimination of the vertical launch method in favor of a rocket-powered rolling take-off from a conventional runway. Because of the heavier gross take-off weight – 21,000 lbs. versus the 11,000 lbs. of a standard T-38 – the N-205B would utilize the beefier F-5 series landing gear.

Still using three Rocketdyne AR-4 motors, the ST-38 could fire any or all rockets for take-off.  Pitching up to an 85° angle of attack after wheels-up and an initial acceleration run, the vehicle would reach Mach 3.3 and top out at 285,000 feet, or 53 miles – high enough to qualify pilots for astronaut wings under Air Force rules at the time, making it a true aerospace trainer.

After reentry and transition from the ballistic to a glide-slope trajectory at 40,000 feet, the ST-38 would then perform a loop with a roll to reverse course and allow the trainer to land at the base of origin. Unlike the initial N-205, no auxiliary rocket motor was proposed.

An added complication for the ST-38 was the fixed aft ventral fin, a holdover feature of the N-205. While not an issue for the vertical launch proposal, it would limit the rotation angle on a conventional runway take-off. Since landings were already restricted to a 9° angle of attack on both versions, the ST-38 would have the same constraint on take-off. Even so, ground roll on take-off was impressive considering the heavier gross weight: 4,453 feet with only one rocket; 1,149 feet with all three firing. The minimum take-off roll for a standard T-38 was 2,300 feet.

T-38A Block-17 aircraft were to be the baseline vehicle for the proposed conversion. One article noted a Northrop spokesman claiming the ST-38 would have 90% commonality with the T-38A’s basic structure.5 However, the original N-205 figure of 75% seems more reasonable considering conversion included the addition of the rocket propulsion motors, modified internal fuel cells, side-stick controls, reaction control nozzles, fixed ventral fin and faired inlet covers, to name just a few differences.

Northrop’s window of opportunity, however, was closing fast as the Air Force’s vision of a manned, winged aerospace plane, and a permanent military presence in space, was about to be overtaken by the events and decisions initiated after Sputnik. 

The Air Force had already lost their leadership role in that arena in October 1958 when President Dwight Eisenhower chose to emphasis the civilian nature of America’s space program by establishing the National Aeronautics and Space Administration as the lead agency in the nation’s space efforts. The designs NASA picked for its near-term manned space vehicles were ballistic-trajectory, blunt-body capsules and not winged aerospace planes. By 1963 more and more funds were being diverted to the growing Apollo program as NASA sought to fulfill President John F. Kennedy’s vow of landing an American on the Moon by 1970. 

At the same time, the growing expenditures on the X-20 and the Air Force’s inability to convince Secretary of Defense Robert McNamara that the vehicle had an operational purpose and was a valuable strategic asset caused the Secretary to cancel the program in December 1963, two weeks after President Kennedy’s assassination and two months after ARPS accepted the first NF-104A from Lockheed. X-20 was only about a year away from flight test at that point. 

A vehicle call the Manned Orbiting Laboratory (MOL), based on the McDonnell Aircraft Corporation’s blunt-body Gemini spacecraft, replaced the X-20 and became the Air Force’s last hope for a manned space program under its aegis. That, too, was cancelled in 1969 amid rising costs, a redundant mission profile with existing reconnaissance satellites and a national budget consumed by the Vietnam War, new social programs and the Apollo effort.

Winged aerospace planes suffered another setback during 1963 as the research focus began to shift to lifting body studies. Ironically, Northrop would build two of the designs for NASA, the M2-F2/F3 and HL-10, both of which began flight tests in 1966. 

The X-15 ended its flight tests in 1968. It would be another decade and a half before a winged aerospace plane flew again in the form of the NASA/Rockwell International Space Shuttle. It would be four and a half decades before the Air Force finally managed to procure and fly its own winged aerospace plane – the unmanned Boeing X-37B.

The success of the NASA-sponsored blunt-body design is indisputable: Americans landed on the Moon on July 20, 1969 and on five subsequent missions. No other nation can yet claim that feat.  But the rush to be the first left lasting consequences. The downward ballistic trajectory of NASA’s budget following Apollo 11 left many critics wondering if the sustained incremental progress of programs like the Air Force’s X-20 would have better served the nation’s interests.

But that is all hind-sight. While the X-20 probably would have succeeded, there is no guarantee that it would have. The same holds true for the ST-38. Yet, it is very exciting to imagine the sight of a Talon streaking to Mach 3+ and crossing into the threshold of space. It would have been a remarkable highlight in the long history of the T-38/F-5 series. The fact that it could have happened in the mid-1960s is even more remarkable.  It makes wondering what the course of aerospace history would have been like, had they both become operational, a fascinating case of “what if…”

Footnotes
  1. http://www.astronautix.com/fam/manonest.htm - This link contains a good background overview of Air Force plans for space operations in the 1950s.
  2. http://www.astronautix.com/craft/dynasoar.htm - This link provides a good overview of the X-20 history.
  3. Noted as proposal NAI-58-366 (May 22, 1958) in “Study Report SR-49756: Program Plan for Study of Advanced Design Trainer,” Northrop Corporation, Los Angeles, August 28, 1959: 3.
  4. Northrop Corporation, “WSDS-248: Summary Report: ST-38 Aerospace Trainer Study,” Los Angeles, April 29, 1963.
  5. Willard E. Wilkes, “Northrop Proposes Space Trainer,” Missiles and Rockets, (September 10, 1962):17.

References and Notes
As noted in the footnotes, these links provide excellent background material for both the Air Force’s “Man-in-Space-Soonest” and X-20 Dyna-Soar programs: http://www.astronautix.com/fam/manonest.htm, http://www.astronautix.com/craft/dynasoar.htm.

The Secret Projects website has a small segment on the N-205B.  It can be found here:  http://www.secretprojects.co.uk/forum/index.php/topic,13808.msg161679.html#msg161679  

Northrop Reports SR-49756 and WSDS-248 were extremely helpful (see footnotes for more detailed description).  If anyone has NAI-58-366 in their possession, this writer would be very interested in obtaining a copy.

A valuable book on the X-20 program is: Dyna-Soar: Hypersonic Strategic Weapons System, Robert Godwin, Apogee Books, 2003, printed by Collector’s Guide Publishing, Inc., Burlington, Ontario, Canada.

Another valuable reference is the monograph: Lockheed N-104A Aerospace Trainer by Scott Libis, photo research by Tony Landis, Air Force Legends Number 204, published by Steve Ginter, 1999

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.

Kristi Harding contributed to this article.





Photo Captions
  1. img156: The Boeing X-20 mockup is shown on a cart with two men for size comparisons. This version of the X-20 was a boost-glide sub-orbital variant with no engines and provisions for a single pilot. Fully orbital versions with engines were planned.  Photo credit: Tony Chong collection.
  2.   IMG_0001b: This scan of an article from the April 3, 1959 issue of The Aeroplane (page 393) details early press releases about the N-205 program. The article contains a fair amount of useful information and was posted on the Secret Projects N-205 link (see references). Interestingly the text mentions a jettisonable ventral fin. The Northrop studies indicated the fin was fixed on this variant as well as on the ST-38.  Credit: Secret Projects.
  3.      IMG_0001a: This close-up scan of the artist’s concept from the article in The Aeroplane issue discussed above shows wing-tip fuel tanks and an inset of the vertical launch platform.  Note the rectangular windows in the area where the bubble canopy would be on a standard T-38. Credit: Secret Projects.                                   
  4.             img157: A beautiful color shot of an NF-104A showing the lit Rocketdyne AR2-3 motor at the base of the vertical tail while the vehicle is in a 70° zoom-climb. Colonel Charles “Chuck” Yeager, the first man to break the sound barrier and commandant of the ARPS at the time, was attempting to win back the altitude record from the Russians in another NF-104A when the aircraft departed into a flat spin, an unwanted first for the F-104 series.  Yeager suffered burns to his face when he ejected at 11,000 feet. The incident was later featured in the 1983 film “The Right Stuff.” Ironically Yeager’s crash occurred on the same day as the announcement of the X-20 cancellation (December 10, 1963). Photo credit: U.S. Air Force, Tony Chong collection.
  5. ST-38 3-view: A general arrangement drawing of the ST-38/N-205B. Note the size of the ventral fin and the eyelet-shaped heat-resistant glass window openings in the canopy replacing the Plexiglas bubble. Also of interest are the leading edge flaps, a feature not found on a standard T-38. Photo credit: Tony Chong collection.
  6. ST-38 loft: A stitched-together series of loft lines and inboard profile scans shows internal details of the ST-38, with many of the parts labeled for identification. Photo credit: Tony Chong collection.
  7.                                                              ST-38 Iso: A much cleaner drawing shows the internal arrangement detail but without identifying labels. Photo credit: Tony Chong collection.
  8.                                 1547-112: A 1962 photo of an N-205 model shows the vehicle in a then-standard Air Force training color scheme with day-glow orange panels. Judging from the eyelet openings lateral visibility would have been terrible inside the cockpit. Photo credit: Northrop Grumman.
  9.                                                                              3989-043: While not apparent at first glance, this 1963 company concept art shows the ST-38 in a dark color scheme as seen by the white lettering on the tail, wings and fuselage. The faired inlet covers are shown to good advantage in this piece. Photo credit: Northrop Grumman.
  10.                                                                 N205b: This is a scan of the Missiles and Rockets article in the September 10, 1962 issue (page 17). The article, like the first one described earlier, is extremely detailed in the description of the vehicle, its systems and its mission profile.  At this point Northrop was only saying the N-205B would reach “at least” 250,000 feet. Photo credit: Tony Chong collection.
  11.                                         img159: An internal Northrop Corp. publication featured the N-205B in one of its articles. Again note the dark color replacing the initial white and orange scheme. Photo credit: Tony Chong collection.
  12.                                                      C-5612-053: The previous image was actually a black and white reproduction of a full-color painting done by a Northrop artist who signed his name as “Todd.” The black color, similar in appearance to the scheme then in use on the X-15, shows up much better in this scan.  Ironically the X-15A-2 would eventually be coated in pink ablative material that was sealed by a white coating, making the vehicle look more like that on the original N-205 scheme. Note that the leading edge flaps do not appear in any of the ST-38/N-205B concept art. Photo credit: Northrop Grumman.
  13.                                      img160: A graph of a typical ST-38 flight profile shows the ballistic trajectory going to 265,000 feet.  Peak altitude was projected to be 285,000 feet.  Note the loop with roll that reverses course to bring the vehicle back to its base of origin. It would pass over the runway at 40,000 feet before initiating the landing procedure.  Estimated total mission time was about 9 minutes. Photo credit: Tony Chong collection.
  14.                                      1137-102: The ST-38/N-205 wasn’t the only variant proposed by Northrop.  A supersonic VIP transport was one such version.  One can only imagine the cramped space inside the cabin. Note the additional slipper-tanks mounted on the wings to carry extra fuel. Photo credit: Northrop Grumman.
  15.                                  T-38 VTOL: Northrop was heavily involved in V/STOL technology in the early 1960s so it’s no surprise a T-38 VTOL variant was proposed. Note the wingtip and tail fairing roll thrusters for stabilization in the vertical lift and hover mode.  Photo credit: Tony Chong collection.
  16. full03: The U.S. Air Force began the quest for a winged, reusable aerospace plane in the mid-1950s.  55 years later they finally achieved their goal with the unmanned Boeing X-37B. The number two vehicle is shown here upon completion of its maiden flight on Saturday, June 16, 2012 after spending 15 months in orbit performing a clandestine mission. Photo credit: U.S. Air Force.

4 comments:

  1. Been looking for info on this for *decades.* Thanks!

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  2. I've been waiting to learn more about the Space Trainer program for years, and here it is, with color artwork, blueprints and all. Brilliant! Thank you so much Tony for keeping the Northrop legacy alive.

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  3. You should also research the N-285B proposal for a naval trainer and light-strike aircraft. I had the opportunity to browse the brochure back when I worked for Northrop.

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    Replies
    1. Evan, it's actually on the list for a future article, but there are a lot of subjects in front of it. Eventually...

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