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“NASA Shuttle Carrier Aircraft – the Titans of the Space Shuttle Program” PART III

By Suresh A. Atapattu
December 3, 2012


Part I: http://www.airliners.net/aviation-articles/read.main?id=157
Part I: http://www.airliners.net/crew/articles/admin.php?id=158


PART III:


The first orbiter spacecraft, Enterprise (OV-101), was rolled out to the public on Sept.17, 1976. On Jan.31, 1977, it was transported 38 miles over land from Rockwell’s assembly facility at Palmdale, Calif., to NASA’s Dryden Flight Research Facility at Edwards Air Force Base to commence the Approach and Landing Test Program (ALT) phase of testing under the management of famed NASA astronaut and pilot Deke Slayton.

The ground tests included taxi tests of the SCA with the Enterprise mated atop the SCA to determine structural loads and responses. It also assessed the mated capability in ground handling and control characteristics up to flight takeoff speed. The taxi tests also validated 747 steering and braking with the orbiter attached.

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Photo © AirNikon Collection-Pima Air and Space Museum

N905NA (cn 20107/86) With Space Shuttle 'Enterprise' on top.


The three manned captive flights that followed the five unmanned captive flights included an astronaut crew aboard the orbiter operating its flight control systems while the orbiter remained perched atop the SCA. These flights were designed to exercise and evaluate all systems in the flight environment in preparation for the orbiter release (free) flights. They included flutter tests of the mated craft at low and high speed, a separation trajectory test and a dress rehearsal for the first orbiter free flight.

The first orbiter free flight was not a simple occurrence and much planning and analysis went into it. NASA had experience dropping the X-15 from the B-52 but not launching off the top of an aircraft. The scientific question was how would the flow field around the in- flight 747 effect the lift of the shuttle orbiter. Some of the scenarios contemplated were: will the shuttle orbiter clear the tail of the 747? Will the shuttle orbiter stall and roll into the 747 upon release? The flight plan called for the combo to climb to attitude and then enter a slight dive to increase airspeed, reduce the 747 engine power, and release the shuttle orbiter. The separation was achieved by the shuttle orbiter pilot firing explosive bolts to separate the orbiter at the three attachment points. The concern was that the orbiter could stall and roll into the 747 beneath it. Lift was needed by the shuttle orbiter but not too much that would induce a stall at separation. The engineers realized that for the clean separation of the shuttle orbiter, the angle of attack relative to the 747 had to be significant. This angle was calculated to be 8 degrees (as opposed to 3 degrees during a captive ferry flight). On the first attempt, it was a clean separation with the orbiter rolling in one direction and the 747 in another with good vertical and lateral separation. The hours of wind tunnel data and analysis was time and money well spent!



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Fitzhugh Fulton pilots the shuttle carrier aircraft as it takes off on the first Space Shuttle Approach and Landing Test. Fred Haise and Gordon Fullerton are aboard the Enterprise to conduct a four-minute descent of 20,000 feet.


In the five free flights the astronaut crew separated the spacecraft from the SCA and maneuvered to a landing at Edwards Air Force Base. In the first four such flights the landings were on a dry lake bed; in the fifth, the landing was on Edwards 'main concrete runway under conditions simulating a return from space. The last two free flights were made without the tail cone (the orbiter was outfitted with a tail cone covering its aft section to reduce aerodynamic drag and turbulence. It was used on all the ferry flights.), which is the spacecraft's configuration during an actual landing from Earth orbit. Without the cone, three simulated Space Shuttle main engines and two orbital maneuvering system engines were exposed aerodynamically. In NASA’s parlance, these flights verified the orbiter's pilot-guided approach and landing capability; demonstrated the orbiter's subsonic terminal area energy management auto land approach capability; and verified the orbiter's subsonic airworthiness, integrated system operations and selected subsystems in preparation for the first manned orbital flight. NASA documented that these flights successfully demonstrated the orbiters ability to approach and land safely with a minimum gross weight and using the center of gravity. This was one of the many crucial contributions by SCA N905NA to give flight to the whole STS program.


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N905NA / 376 (cn 20107/86) Taking off with Enterprise on the fourth Approach and Landing Test, one of only two flights flown without the streamlined tailcone.


The final phase of the ALT program prepared the spacecraft for four ferry flights. Fluid systems were drained and purged, the tail cone and elevon locks were installed. The forward attachment strut was replaced to lower the orbiter's cant from 8 to 3 degrees. This reduces drag to the mated vehicles during the ferry flights. NASA documented these test in minute detail and used the data to shape the final configurations of the spaceflight orbiters

According to NASA records, after the ferry flight tests, OV-101 was returned to the NASA hangar at Dryden and modified for vertical ground vibration tests at NASA's Marshall Space Flight Center, Huntsville, Ala. The next phase of the SCA contribution involved shuttling the shuttle around the country as the testing moved to other areas. On March 13, 1978, the Enterprise was ferried atop the SCA to MSFC. At Marshall, Enterprise was mated with the external tank and SRB and subjected to a series of vertical ground vibration tests. These tested the mated configuration’s critical structural dynamic response modes, which were assessed against analytical math models used to design the various element interfaces. These were completed in March 1979. On April 10, 1979 the Enterprise was ferried to Kennedy Space Center, mated with the external tank and SRB and transported via the mobile launch platform to Launch Complex 39-A, the Enterprise served as a practice and launch complex fit-check verification.

In May and June 1983, Enterprise was ferried to France for the Paris Air Show as well as to Germany, Italy, England and Canada before returning to Dryden. They also stopped in Iceland on the trip.

Over Heathrow

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Photo © Howard Pain


At Stansted:

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Photo © Mick Bajcar


At Fairford:
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Photo © Ian Powell


N905NA (cn 20107/86) "Trundling down the Fairford taxiway."

Over Manchester:
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Photo © Malc Southern


At Paris:
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Photo © Gerard Helmer


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Photo © Mark Carlisle


At Cologne:
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Photo © Joachim Eichner


At Ottawa, Canada

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Photo © Rudy Bos



In Iceland
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Photo © Eggert Norðdahl




From April to October 1984, Enterprise was ferried to Vandenberg AFB and to Mobile, Ala., where it was taken by barge to New Orleans, La., for the United States 1984 World's Fair. In November 1984 it was transported to Vandenberg and used as a practice and fit-check verification tool. On May 24, 1985, Enterprise was ferried from Vandenberg to Dryden. On Sept. 20, 1985, Enterprise was ferried from Dryden Flight Research Facility to KSC. On Nov. 18, 1985, Enterprise was ferried from KSC to Dulles Airport, Washington, D.C., and became the property of the Smithsonian Institution.


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Delivery flight of Enterprise to the Smithsonian in 1985


The Enterprise was built as a test vehicle and remained as such hence is not equipped for space flight. In a strange twist, OV-101 was the victim of its success. The original thoughts were to convert OV-101 into a spaceflight orbiter however the modifications that resulted from the extensive testing resulted in it being more feasible and economical to covert OV-099 (Challenger) which was the static test orbiter into a spaceflight orbiter.

Milestones in the ALT Program:



Nov. 4, 1976 Complete 747 shuttle carrier aircraft modification, rollout, Boeing


Jan. 14, 1977 Boeing 747 shuttle carrier aircraft delivered to DFRF


Feb. 7, 1977 Enterprise (OV-101)/shuttle carrier aircraft mate start


Feb. 15, 1977 Complete Enterprise (OV-101)/shuttle carrier aircraft mated ground vibration test and taxi tests.


Feb. 18, 1977 Conduct first inert captive flight, DFRF (2 hours, 5 minutes), Enterprise (OV-101).


Feb. 22, 1977 Conduct second inert captive flight, DFRF (3 hours, 13 minutes), Enterprise (OV-101).


Feb. 25, 1977 Conduct third inert captive flight, DFRF (2 hours, 28 minutes), Enterprise (OV-101).


Feb. 28, 1977 Conduct fourth inert captive flight, DFRF (2 hours, 11 minutes), Enterprise (OV-101).



March 2, 1977 Conduct fifth inert captive flight, DFRF (1 hour, 39 minutes), Enterprise (OV-101).



June 18, 1977 Conduct first manned captive active flight, Enterprise (OV-101)/shuttle carrier aircraft, DFRF (55 minutes, 46 seconds).



June 28, 1977 Conduct second manned captive active flight, Enterprise (OV-101)/shuttle carrier aircraft, DFRF (1 hour, 2 minutes).



July 26, 1977 Conduct third manned captive active flight, Enterprise (OV-101)/shuttle carrier aircraft, DFRF (59 minutes, 50 seconds).



Aug. 12, 1977 Conduct first free flight, ALT, tail cone on, DFRF (5 minutes, 21 seconds), Enterprise (OV-101), lake bed Runway 17.


Sept. 13, 1977 Conduct second free flight, ALT, tail cone on, DFRF (5 minutes, 28 seconds), Enterprise (OV-101), lake bed Runway 17.


Sept. 23, 1977 Conduct third free flight, ALT, tail cone on, DFRF (5 minutes, 34 seconds), Enterprise (OV-101), lake bed Runway 15.


Oct. 12, 1977 Conduct fourth free flight, ALT, first tail cone off, DFRF (2 minutes, 34 seconds), Enterprise (OV-101), lake bed Runway 17.


Oct. 26,1977 Conduct fifth free flight, ALT, final tail cone off, DFRF (2 minutes, 1 second), Enterprise (OV-101), concrete Runway 04


Nov.5-Nov 18,1977 Four ferry flight tests, DFRF (total time:15 hrs 28 minutes)


Dec. 9 1977 Complete approach and landing flight tests, including ferry flights, Enterprise (OV-101)

Ferry Flight


The first step after landing is the prepping of the aircraft post-flight and the removal of harmful and toxic remnants of its space flight such as any remnant propellant from its space maneuvering system. The orbiters are then placed on top of the SCAs by the use of the Mate-Demate Device (MDD).

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Photo © Ben Wang



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Photo © Brian Lockett



The MDD is a large gantry-like structure which hoists the orbiters off the ground for post-flight servicing, and then mates them with the SCAs for ferry flights. Once placed upon the SCA, the orbiter has a special cone fitted over her engines to provide for aerodynamic streamlining of the airflow. Upon arrival at the destination, this process is repeated in reverse. The orbiter is then attached r which drives it into its hanger for servicing for the next mission.

The ferry flights were originally standard operating parts of each mission as the orbiters landed at Edwards Air Force Base in California. However, the $1.8 million added ferry flight cost and additional time in processing led to the return of the orbiter to KSC unless effected by weather. The first choice of landing was the SLF in Florida but the dynamic weather situation would often violate the landing constraints hence Edwards was used slightly more than half the times thus warranting the ferry flights back to KSC. Additionally, the orbiter underwent major servicing in Palmdale on certain occasions during the service life hence that too required ferry flights.

The flight crew of the SCA is drawn from a pool of certified NASA pilots and engineers who spend their time working on other NASA aeronautic programs. They maintain their currency by flying a SCA at least once every 60 days. Typically, the SCA flew once every 30 days for training purposes. Commercial flight simulators were used also to maintain the crew standards and augment flight hours. The crew represents a collection of very high time pilots and engineers proficient in a range of NASA aircraft. Most, if not all, have spent a large amount of time as SCA crew and consider the final deliveries of the orbiters as a final milestone in their flying careers. With the massive crowd attention and interest generate by the delivery of Discovery and Enterprise, it is a nice sendoff to the crew of the SCA as well. They have been unsung heroes of the STS program.

As the end of the STS program, the personnel associated with the SCA marked the legacy of the NASA 905 with a special unveiling of an updated sight that had been lost to history. A series of graphic representations of space shuttles being carried aboard a NASA Shuttle Carrier Aircraft were recently affixed again to the forward fuselage by the forward doors on both sides. The logos above the main deck windows provide a visual history of all of the shuttle ferry missions flown by that aircraft, beginning with the shuttle approach and landing tests at NASA's Dryden Flight Research Center on Edwards Air Force Base in 1977 and including the upcoming ferry flights of the shuttles Discovery, Enterprise and Endeavour from the Kennedy Space Center to their final museum display locations. The graphics depict a total of 222 shuttle ferry flights by NASA 905 from 1977 through 2012. With the addition of logos representing five flights in which the modified 747 carried the prototype shuttle Enterprise aloft for the approach and landing tests in 1977 and two ferry flights of Boeing's Phantom Ray technology demonstrator in late 2010 and 2011, the graphics recall a total of 229 piggyback missions for N905NA.


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Photo © Dean Straw

If you closely in this picture from 1978, you can see the logos that were in place depicting her mission tally by the forward passenger door. These logos were taken off with the new paint scheme of 1983 and this fact was lost to history. Fast forward to 2012, the final mission count has been placed back in the correct place and will remain on the aircraft.

NASA 905 carried Columbia aloft 60 times, Challenger 20 and Atlantis 35. When the deliveries to museums in Washington, New York and Los Angeles are completed, it will have carried Discovery 38 times, Endeavour 12 and Enterprise 57 times on ferry flights, along with five missions in which it released the prototype orbiter for steep descents to the runways at Edwards in 1977.

PART IV: UPCOMING



Written by
Suresh A. Atapattu

Suresh A. Atapattu is a biomedical engineer specializing in cardiology. He has had a longstanding research interest in the functioning of the human physiology in spaceflight. He was given unprecedented access and permission by NASA to document Space Shuttle processing at the Kennedy Space Center over the last decade of operations including the retirement and placement in museums. Some of his NASA photography can be seen at his website at http://www.atapattu.net or here at Airliners.net http://tinyurl.com/d7mrsa2

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