27 February 2017

A 1964 Proposal for a Small Lifting-Body Shuttle with "Staged Reentry"

Image credit: NASA
A lifting body is an aircraft that relies for lift on the shape of its fuselage, not on protruding wings. Many early lifting bodies were triangular as viewed from above and "tubby" as viewed from the side. The latter characteristic earned some of them the sobriquet "flying bathtubs."

Theoretical work on lifting bodies began in the United States in the 1950s at National Advisory Committee for Aeronautics (NACA) laboratories. Early lifting bodies took the form of horizontal half-cones with rounded noses and flat tops. They were viewed mainly as steerable reentry bodies for nuclear warheads launched on Intercontinental Ballistic Missiles. By the end of the 1950s decade, however, as the 1958 Space Act transformed NACA into NASA and transferred to it most Department of Defense space facilities and projects, some engineers began to propose that lifting bodies serve as piloted reentry vehicles.

NASA opted to launch its astronauts in conical capsules rather than lifting bodies, but the lifting-body concept was by no means abandoned. In fact, it became a common element of U.S. space planning. In 1961, for example, both The Martin Company and the Convair Division of General Dynamics gave their proposed Earth-orbital/circumlunar Apollo spacecraft design lifting-body Command Modules.

Cutaway view of The Martin Company's lifting-body Apollo Command Module with portions of adjoining components visible (left - the Launch Escape Propulsion System; right - housing for the tunnel leading to the the Mission Module). This Command Module configuration, which Martin called Model 410, measured 12.5 feet long from its dome-shaped nose to its flat aft bulkhead and 12.5 feet across the widest part of its flat top. Image credit: The Martin Company/NASA
The same year, the U.S. Air Force, as part of its LUNEX study, proposed a piloted moonship comprising a landing stage with a lifting body stacked on top. In 1963, Philco Aeronutronic designed a lifting-body piloted Mars lander on contract to NASA's Manned Spacecraft Center in Houston.

Also in 1963, engineers and test pilots at the NASA Flight Research Center (FRC - later Dryden FRC; now Armstrong FRC) at Edwards Air Force Base (AFB), California, began piloted test flights of the M2-F1 lifting body (image at top of post). The lightweight M2-F1, a glider with a tubular steel frame and a mahogany plywood skin, was towed aloft a total of 77 times between March 1963 and August 1966 using a souped-up Pontiac Catalina convertible or a Douglas C-47/RD4 "Gooney Bird" aircraft. During some flights, the M2-F1 included a small rocket motor.

M2-F1 test flights showed that the lifting-body concept had promise, so NASA funded a program of lifting body development and test flights at FRC. It lasted from 1966 into the 1970s.

The M2-F1 confirmed, however, what 1950s experiments had shown: that lifting bodies become increasingly unstable as their speed decreases. With this in mind, in January 1964, Clarence Cohen, Julius Schetzer, and John Sellars, engineers with the aerospace firm TRW, filed a patent application for a piloted lifting-body spacecraft design that could accomplish what they called a "staged reentry." The U.S. Patent Office granted their patent (No. 3,289,974) on 6 December 1966.

Explaining the need for their invention, the TRW trio noted that the Mercury capsule, flown for the last time in May 1963, had given its astronaut occupant essentially no ability to alter his spacecraft's course after he fired its solid-propellant deorbit rocket motors. The astronaut could control the timing of his deorbit burn; an early burn would cause his capsule to plunk into the ocean short of its planned splashdown area, while a delayed burn would cause it to overshoot its target.

The Mercury astronaut could not use the atmosphere to steer his capsule any great distance away from the ground track of its orbit. In aerospace terms, the Mercury capsule followed a ballistic trajectory from deorbit burn to splashdown and had very limited cross-range capability. The ballistic trajectory subjected the Mercury astronaut to a deceleration load equal to about eight times the pull of Earth's gravity.

The Gemini and Apollo reentry capsules, under development at the time Cohen, Schetzer, and Sellars filed their patent, would each feature an offset center of gravity about which they could roll while they moved at high speed through Earth's upper atmosphere. This would provide some lift and cross-range capability and help to limit deceleration loads. Both capsules would, however, become unsteerable and lose lift as they lost speed. Neither could be guided toward a specific touchdown point after their parachutes deployed. Steerable triangular parawings had been proposed for both, but such systems were judged to be too complex, heavy, costly to develop, and prone to failure.

The flat-bottomed DynaSoar - not a lifting body - had been designed for both steerable, low-deceleration Earth atmosphere reentry and stability and steerability at low speeds; however, the Department of Defense space plane's flat belly and narrow-edged wings and fins made it difficult to cover with heat shield materials. Protecting the triangular glider adequately from reentry heating threatened to boost its weight so much that its ability to maneuver in the lower atmosphere might be compromised.

Cohen, Schetzer, and Sellars' staged reentry spacecraft was really two vehicles: a fairly conventional (though quite compact) two-seater jet plane and a lifting-body "pod." The delta-winged jet would nest within the upper part of the pod with its bubble cockpit canopy protruding from the lifting body's flat top surface.

Partial cutaway drawing showing the small jet plane nested within the lifting-body "pod." One of the jet's pair of downturned vertical stabilizers is visible. Image credit: U.S. Patent Office/TRW
Standing atop an unspecified two-stage booster rocket on the launch pad before liftoff, the staged-reentry spacecraft would point its bulbous nose at the sky. The crew would enter through a hatch in the side of the streamlined fairing linking the lifting body to the booster, then would climb up through a drum-shaped airlock in the lifting body's flat aft bulkhead to reach acceleration couches arranged one behind the other (one above the other on the launch pad) in the lifting-body pod. The mission commander would take the front/top couch. Both couches would face control consoles.

The pod would include two abort rockets and one deorbit/abort rocket. In the event of booster malfunction during first-stage operation, the astronauts could ignite the three aft-facing rocket motors to blast their spacecraft free of the booster. The crew couches would automatically move up rails into the jet airplane cockpit and hatches would close in the plane's belly, sealing the crew inside. After the abort engines expended their propellants, the astronauts would separate from the pod in the jet and descend to a controlled landing at the launch site or at any airport within several hundred miles of the abort point.

Assuming, however, that an abort did not become necessary, the two abort rockets would eject out the back of the lifting body immediately after second-stage ignition. Cohen, Schetzer, and Sellars estimated that discarding the unused motors at that point in the flight would enable extra payload in Earth orbit equivalent to 90% of the motors' mass.

Riding the rails: TRW's method for moving astronauts between the lifting-body pod and the jet airplane cockpit is reminiscent of Gerry Anderson's Thunderbirds. Image credit: U.S. Patent Office/TRW
Once in orbit, the jet airplane canopy would provide the crew with views of the Earth and space. The crew could ride their couches up and down the rails to move between the pod and the jet airplane. In addition to living space, the pod volume would contain payload (for example, in-flight experiment gear), avionics, and life support equipment. The jet plane's belly, wing undersides, and single air intake cowl would form the "ceiling" of most of the pod living space.

The internal arrangement of the pod was, however, of little real concern to the TRW engineers; in fact, they argued that the lifting-body pod might serve merely as a "jettisonable heatshield" fitted with deorbit and abort rocket motors and avionics. In that case, the jet airplane cockpit would comprise the staged-reentry spacecraft's sole crew volume. 

TRW's staged reentry vehicle viewed from above and aft. A = jet airplane canopy; B = panel protecting jet airplane's nose; C = top surface of airplane fuselage and wings; D = lifting body top surface; E = jet airplane horizontal flap (1 of 2); F = lifting body underside; G = ejectable abort rocket motor (1 of 2); H = deorbit/abort rocket motor; I = parachute/landing aids compartment cover; J = movable control flap with actuator (1 of 4); K = flat aft bulkhead; L = airlock outer hatch. Image credit: U.S. Patent Office/TRW
Cohen, Schetzer, and Sellars envisioned that the crew would have at their disposal a display that would show landing areas on Earth as they passed within range of their orbiting spacecraft. When the desired target landing area came within range, the crew would command the computer that generated the display to orient the spacecraft using small thrusters so that its flat aft bulkhead pointed in its direction of motion. It would then ignite the deorbit rocket motor. As the spacecraft fell toward the atmosphere, the thrusters would automatically turn it so that its nose faced in its direction of motion. The crew, meanwhile, would ride their couches into the jet airplane cockpit.

As the spacecraft entered the atmosphere, four aft-mounted movable control flaps would adjust ("trim") the amount of lift the lifting-body shape would generate. At first, the spacecraft would descend at a shallow angle designed to limit the deceleration felt by the crew to less than twice the pull of Earth's gravity. The crew could, if required, take advantage of the lifting body's cross-range capability to steer toward landing sites far north or south of their orbit ground-track. 

The jet airplane detaches from the lifting-body pod. A = empty abort rocket compartment (1 of 2); B = experiment equipment and supplies; C = jet airplane separation rod with mounting pin (1 of 3); D = panel covering subsystems (for example, life support equipment); E = jet engine; F = vertical stabilizer (1 of 2); G = vertical control surface (1 of 2); H = rear landing skid (1 of 2). Image credit: U.S. Patent Office/TRW
Twelve minutes after the start of reentry, at an altitude of about 50,000 feet, the staged-reentry spacecraft would drop below supersonic speed, after which "staging" - separating the jet airplane bearing the crew from the plummeting lifting-body pod - could occur at any time. Separating the jet would open the pod crew volume to the outside environment. The pod would then deploy a parachute and other landing aids (for example, a flotation system) from an aft-mounted compartment and descend nose-down almost vertically to a splashdown or land landing. The problem of lifting-body instability at low speed would thus be eliminated.

In some ways, this approach resembled the Soviet Vostok land landing method. Vostok, the first piloted orbital spacecraft, was a modified spy satellite. Its spherical reentry capsule landed at too high a speed for the cosmonaut inside to escape injury, so he or she ejected low in the atmosphere, deployed a personal parachute, and descended separate from the capsule.

The TRW engineers expected that the astronauts could land safely in the lifting-body pod if they could not separate from it in the jet plane. Assuming, however, that they separated as planned, they would glide away from the pod in the jet. After they ignited the jet's engine, they would fly around the landed pod to locate it for recovery personnel, then land at a predesignated airport. The subsonic jet would carry enough fuel to permit the astronauts to reach backup airports if, for example, weather conditions became uninviting at the predesignated landing site.

By the time the U.S. Patent Office granted Cohen, Schetzer, and Sellars their patent in December 1966, NASA FRC had begun flights of the M2-F2, an all-metal lifting body built by the Northrop Corporation. It was the first of NASA's "heavyweight" lifting bodies. The research aircraft was designed to be borne aloft beneath the wing of a specially modified B-52 and released so that it could glide to a landing on a dry lake bed runway at Edwards AFB. After it proved itself in gliding flight, pilots would ignite the M2-F2's single four-chamber XLR-11 rocket engine for high-speed and high-altitude tests.

NASA's M2-F2 heavyweight lifting body (left) flies beside an F-104 chase plane, 16 November 1966. Image credit: NASA
Perhaps because lifting bodies had a reputation for being difficult to fly, engineers and test pilots were slow to acknowledge that the M2-F2 had significant, correctable control problems. Specifically, it was "soft" (slow) in responding to pilot control inputs, and prone to wild pilot-induced roll oscillations. On 10 May 1967, on its 16th flight, these problems caught up with the M2-F2. With Bruce Peterson at its controls, the M2-F2 crashed onto the Edwards AFB dry lake bed and flipped end over end six times. Miraculously, Petersen survived. Just as miraculously, so did NASA's lifting body research program.

Over the next three years, the M2-F2 was redesigned and rebuilt as the M2-F3, which included a third vertical stabilizer. The new centrally mounted fin markedly improved the aircraft's control characteristics.

The M2-F3 lifting body in 1970. Image credit: NASA
Between 2 June 1970 and 20 December 1972, the M2-F3 flew 27 times. After three unpowered gliding flights, William Dana lit up the M2-F3's XLR-11 rocket engine after release from the B-52 to accomplish its first powered flight (25 November 1970). During its 26th flight (13 December 1972), with Dana at the controls, the M2-F3 reached its fastest speed (Mach 1.6, or 1.6 times the speed of sound). On its final flight, John Manke took the aircraft to its highest altitude (71,500 feet). A year later, NASA transferred the M2-F3 to the collections of the Smithsonian Institution in Washington, DC, for display.

Sources

Patent No. 3,289,974, "Manned Spacecraft With Staged Re-Entry," C. Cohen, J. Schetzer, and J. Sellars, TRW, 6 December 1966

Apollo Final Report: Configuration, ER 12004, The Martin Company, June 1961

Wingless Flight: The Lifting Body Story, R. Dale Reed with Darlene Lister, NASA SP-4220, The NASA History Series, 1997

International Rescue Thunderbirds Agents' Technical Manual, Sam Dunham with Graham Bleathman, Haynes Publishing, 2012

19 comments:

  1. I thought it was Col. Steve Austin who flipped the M2-F2 six times.

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    1. LOL. No, he didn't do his own stunts. My understanding is that Petersen suffered a severe back injury, but needed no bionic replacement parts.

      Petersen's crash did, however, become the footage used in the titles of THE SIX-MILLION-DOLLAR MAN, as you indicate. I never missed that show. I think my favorite episode was the one where Steve flew the lifting body that nearly killed him after it was repaired, and outed the saboteur who had caused the first crash.

      BTW, $6 million wouldn't buy you a bionic finger nowadays, I expect.

      dsfp

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    2. I will say this--such a staged re-entry vehicle would have been perfect for a scenario similar to what you have in the movie "Life"

      One of the containers starts rocking right as the astronauts are told they are off course. They get inside the mini-plane and escape right as the container opens.

      The nose falls into the volcano and the entity goes up in flames with it.

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  2. BTW, great article. Thanks for posting it.

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    1. You are welcome. Thanks for reading it.

      dsfp

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  3. Hi David.
    This is a very welcome article, I've just finished reading "Flying without wings". This is the history of NASA's lifting body research, written by Milton O Thompson & Curtis Peebles, an excellent & informative read.
    Kerrin

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    1. I don;t think I've read that one! Thanks for the heads up.

      dsfp

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    2. Milton O Thompson was one of the test pilots, the book covers the late 50's through to the mid 60's. There's a great chapter about the hot rodded tow car they used for the initial lifting body tests before the air drops.
      Kerrin

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  4. I wonder if this may make a return as the HOT EAGLE/SUSTAIN

    Maybe as a way to service Venus airships
    https://en.wikipedia.org/wiki/High_Altitude_Venus_Operational_Concept

    Publiusr

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    1. Could be. I don't know if the Venusian atmospheric composition would affect lifting body performance.

      dsfp

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  5. Randy Campbell03 March, 2017 23:12

    Very nice article, though I can see the Vostok comparison I'm curious as to why the more obvious comparisons to the Kosmoplan (http://astronautix.com/k/kosmoplan.html) and later VKK (http://astronautix.com/v/vkk.html)concepts weren't made? Speaking of lifting bodies though are you going to do anything on the Lenticular designs at some point? If so I'd be interested in your take on specifically the Apollo Lenticular which if you look at the bottom illustration here: http://www.astronautix.com/a/apollolenticular.html you might note a peculiar indication with the deployable wings. Nobody's been able to find much direct information on the design but it LOOKS like the wings do a "Spaceship One" type angle which is odd since it wouldn't be very effective given the "capsule like" entry dynamics.

    Just some thoughts :)

    Randy

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    1. Randy:

      I could shoot off in all kinds of directions with my posts - one of the challenges is to stay on topic and not get distracted by some other fascinating study so I abandon one post and start on another. Unfortunately, sometimes I'm not very good at that.

      The Vostok reference is meant to illustrate how the scheme described in this post involved, in effect, bailing out of a vehicle that would not enable a safe astronaut landing. Vostok hit the ground too hard, and the data available in 1964 indicated that a lifting body would be uncontrollable at low (landing) speeds. Hence the need to get out before the spacecraft might injure the astronaut(s).

      Incidentally, the Soviets claimed that Gagarin landed in Vostok 1 (he ejected) and that subsequent Vostok cosmonauts ejected but could land in the capsule if necessary. The TRW team made flying off in the jet their preferred method, but claimed a crew could ride the pod to the ground.

      I have no plans to write about lenticular Apollo designs right now, but who knows what the future might hold?

      Thanks for your inputs -

      dsfp

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    2. Randy Campbell04 March, 2017 15:35

      IIRC the Soviets HAD to claim he landed in the capsule for official reasons. To acclaim an official 'first' the "Pilot" has to remain in the vehicle for the whole flight per record regulations. (It was one of the very minor reasons that the Orbital X-15B concept was turned down)Since the Soviets controlled all access to the primary launch and landing operations but there was public proof that Gagarin was alive and in orbit so they simply informed the authorities that he had landed in the capsule in fulfillment of international regulations and 'claimed' the first man in orbit. That "technically" makes Alan Sheppard the FIRST man in space as he is shown from start to finish in the vehicle but I doubt anyone will ever push the actual issue. Gagarin is officially the first man in space/orbit and I'm pretty sure it will remain that way. Just a fun factiod :)

      Randy

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    3. Randy Campbell06 March, 2017 18:46

      Shooting off in different directions JUST because there's all sorts of interesting stuff out there? You? Like you'd get distracted by "shiny" stuff the NASA study on an sub-orbital delivered fighter plane (NASA TM33 IIRC) or a Russian hybrid reusable spacecraft concept from the back in 2015 which combined a capsule and an airplane (see: http://iaass.space-safety.org/wp-content/uploads/sites/24/2015/07/JSSE-VOL.-2-NO.-2-DECEMBER-2015-LR-HYBRID-SPACECRAFT.pdf) nahhh, that would NEVER happen ;)

      Randy

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  6. This over the top complexity make this a unpractical spacecraft
    That Gerry Anderson like hardware has to work flawless
    Like enormous airtight seal between the Airplane and Lifting body.
    or the Rail system for seats

    Ihe Drawing stagedreentry2a.jpg show the Lifting body got parachute (point I)
    means it will be recover also.

    i would go for more practical approach
    Give the Lifting body simply sweep wing and ejection seats for landing.
    Also far cheaper as this "over the top" proposal

    The Six-million Dollar man is also delightful "over the top" series to watch !
    If you not know the 1970s series take a look and be delighted.

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    1. I was a big fan of THE SIX-MILLION DOLLAR MAN when it was on originally. Looking at it now, it seems pretty horrible. That's the case with quite a few TV shows I loved in the 1960s and 1970s. Not so much ST:TOS, however. Not sure if that's because I loved/love it so much or because it really stands the test of time. The 1960s TV BATMAN is also great fun still - a kid can enjoy it for the gadgets and adventures, an adult for the humor (and gadgets and adventures).

      I agree that this is not a practical scheme. It's still interesting even if it is goofy. You're going to love the lunar landing post I'm working on now. Totally unworkable, but some awesome robotics/teleoperations.

      The text describes how the pod would descend, minus crew or jet, to a splashdown or land landing, nose first. One might argue that letting the crew descend in the pod, in couches oriented to protect them, would make more sense. The inventors claim that the crew could ride to the surface in the pod if need be; why not make that the standard modus operandi?

      dsfp

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    2. Randy Campbell04 March, 2017 16:12

      Patents in general don't have to be "practical" in basic design or function* just in general principle in a new and innovative way. Practicality is determined by if you can actually get the patent to work in practice.

      In practice, (since I'm looking to use the design and similar in a possible time line :)) and probably actually assumed by the ones who wrote the patent you don't have that 'seal' you have a by the aircraft rests in that is sealed from the LB. This is obvious actually as from experience most military members who WORK around aircraft are well aware they leak, smell, and off-gas to much to be inside your sealed environment. The rails are gone and the crew rides up and down in the aircraft with s hatch connection to the inside of the LB. You run into issues with having more than two crew but enlarging the aircraft by taking space from the LB should be pretty straight forward. Especially as all separation is at subsonic speeds.

      And that's if you have an LB with space in it. Another 'practical' design is the LB is just a shell with the reentry systems which is dumped once that event is over as per the VKK design I pointed to earlier.

      The main reason for having the airplane component, (and not landing the crew in the LB with or without wings) is the airplane then slots right in to regular air operations where as the LB/Winged-LB never does and will always require special handling for landing. I always say an aircraft is not a spacecraft and vice-versa but in this case you actually have both and they fill the primary missions of each subset better than a single vehicle would. Albeit at a probably higher initial and operations cost but probably cheaper in a the long run.

      And I have to be amused that the VERY first thing I thought as I looked at the fourth patent drawing, (https://1.bp.blogspot.com/-PQYJ4qEevq4/WLR8dC4DYlI/AAAAAAAAbE4/TCVIN2O6wO8rYfuM5uJV4EdnzB674nqQwCEw/s1600/stagedreentry2b.jpg) was "That's an oddly Shuttle shaped hole that non-shuttle looking aircraft leaves behind" :)

      Randy
      *In fact I have a friend who's hobby is collecting official motor company patents for new devices and figuring out how the patents DON'T work and how to MAKE them work as non-working patents is a standard industry trick to prevent theft.

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  7. i'm still a fan of THE SIX-MILLION DOLLAR MAN
    but today i love this campy look and feel, what you have watching trash move like STARCRASH

    >the lunar landing post I'm working on now. Totally unworkable, but some awesome robotics/teleoperations.

    oh here we go again, let me guess ?
    JPL infamous "let send lunar ascent stage in pieces up and build to together with
    remote control waldos on trucks, then find a poor bastard we can put on top Atlas Centaur and send him to Moon..."!

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  8. You are about 75% correct. I have some "new" documents, plus it a Saturn C-3, intermediate between a C-1 and and C-5, not an Atlas-Centaur.

    dsfp

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