The Gemini paraglider / Rogallo Wing

[laszlo]

They look like they'd have been a real challenge to land, what with the tiny windows, especially knowing when and how much to flare. It pretty much would have to have been an instrument approach and/or talked down from a chase plane. The test pilot astronauts would have loved it once the bugs were worked out.

[Blackstar]

They look like they'd have been a real challenge to land, what with the tiny windows, especially knowing when and how much to flare. It pretty much would have to have been an instrument approach and/or talked down from a chase plane. The test pilot astronauts would have loved it once the bugs were worked out.

There were several challenges with the paraglider. Deployment was a big one. Controllability was another. By the end of the program they had mostly worked these things out. However, my impression is that the risk was still pretty high for them. In other words, they might have gotten to a place where it could be deployed successfully 9 out of 10 times. But when a parachute deploys successfully 999 out of 1000 times, which do you want to rely upon?

Similarly, the controllability required, as you noted, knowing exactly when and how much to flare. But that was compounded by the fact that the paraglider was attached by wires and there was a lag, so the pilot would have to command the flare at just the right moment before it was needed, and then hopefully it happened when the vehicle was in the right position over the ground.

I have delayed publishing the last part of my paraglider article. It won't be tonight, it will probably be next week. Somebody told me that he has some great photos to provide that need to be scanned, and I'm waiting for them. Apparently he has a photo of a drop test aircraft with capsule silhouettes painted on the nose.

Also, somebody shared with me an early 1970s history paper on the paraglider test program. It is consistent with what I wrote, but he had an interesting perspective that I also want to include. I assumed that the paraglider development was a clear response to a requirement (water landing was expensive). However, he suggests that it had more to do with the person running the Gemini program who was enamored of the technology, rather than a response to a requirement. Both things can be true, but I want to mention that in my conclusion.

[laszlo]

I'm eagerly awaiting part 3.

Thinking over this whole concept, which seemed like a great idea 60 years ago (at least at first), I am really puzzled that it got as far as it did. The suggestion that it may have been a manager's techno-fascination makes a lot of sense to me when the system is considered as a whole.

Parachutes were a well-understood and developed technology back then. They didn't require much in the way of ancillary equipment and power. Although electrically triggered, most of the actual energy to deploy them was provided by pyrotechnics, also well-understood and developed. The main parachute was deployed in a passive fashion, pulled from its container by the pilot chute. The pilot chute was normally pulled from a mortar by the drogue, without the mortar being fired unless the drogue failed. The drogue was the only one actually fired from a mortar in every case. The reefing cutters were powered by pyrotechnic time-delayed charges initiated by a simple lanyard pull. Parachute storage was simple, nominal deployment fired a single mortar. Inflation was accomplished by aerodynamic forces and controlled by time-delayed pyrotechnics. Once the main chute was disreefed and the bridle deployed, the system was entirely passive through splashdown.

Compare this to the paraglider system which needed its structure inflated from an onboard gas source, the heatshield jettisoned, landing skids deployed and motors and batteries to power the control cable reels. The weight difference alone makes me puzzled as to why this was seriously considered. Add in the relative complexities of the systems and all the components that needed to be developed and flight-qualified and it was a real puzzle to me how the idea got as far as it did.

The infatuated manager makes a good explanation.

[Blackstar]

Parachutes were a well-understood and developed technology back then. They didn't require much in the way of ancillary equipment and power. Although electrically triggered, most of the actual energy to deploy them was

SNIP

Compare this to the paraglider system which needed its structure inflated from an onboard gas source, the

What I don't have is a lot of primary source documentation on the program. That documentation would be things like test flight reports, contractor quarterly or monthly progress reports, and Gemini program documents about the incorporation of paraglider into the spacecraft. If that stuff exists, it is buried in archives. However, there is good secondary source material on the program, in the form of a history paper, sections of books on Gemini, and memoir accounts. They provide the overall picture, although specific questions would require access to primary source material.

You noted that the parachute is relatively simple in construction and operation vs. the paraglider. Something I would add is that it undoubtely weighed a lot less. That's a specific that I would really like to know. What was the weight of the Gemini parachute vs. the entire paraglider system? The paraglider system included the inflatable wing and gas canister(s), the control mechanisms, and also the landing gear. I suspect that the landing gear alone added up to a lot of weight.

There's another systems engineering issue that is harder to explain, but certainly would have been something that the Gemini program had to deal with--not only holding mass margin for all the paraglider systems (like the landing gear), but also holding open certain engineering decisions while awaiting the availability of the paraglider. As one example, think of the moving parts attached to the cables to the paraglider. Those cable drums were to be mounted underneath the heat shield. As they were designing the Gemini, there were certain decisions they could not make about the design of the back end of the spacecraft until they knew if they were going to include that system or not include it. So they were not developing blueprints for that section, and/or they were holding mass and volume margin and not doing anything with it because they might need to put those cable drums and actuators in that space.

Something that happens with spacecraft design is that designers want to solve the problems they have to solve as soon as they can, and if they have to delay solving some of them because they await some other decision, that can cost money and time (which is money).

Alan Stern, who ran the New Horizons mission to Pluto, has described this before. For a long time he did not know which rocket--Atlas or Delta--NASA would select to launch New Horizons. Because of that, they had to hold open a bunch of engineering decisions. That actually cost them money, and if NASA had picked a single launch vehicle earlier, the program could have spent that money on other things.

[hoku]

A few photos from Sep 12, 1962 showing Half Scale Test Vehicle 001 and wing 002(?) at MSC. I also like the bubbly shapes of the early L(E)M mock-up.

https://www.jfklibrary.org/asset-viewer/archives/jfkwhp-1962-09-12-b#?image_identifier=JFKWHP-KN-23793
https://www.jfklibrary.org/asset-viewer/archives/jfkwhp-1962-09-12-b#?image_identifier=JFKWHP-KN-C23688
https://www.jfklibrary.org/asset-viewer/archives/jfkwhp-1962-09-12-b#?image_identifier=JFKWHP-KN-C23689
https://www.jfklibrary.org/asset-viewer/archives/jfkwhp-1962-09-12-b#?image_identifier=JFKWHP-ST-A16-37-62

[ccdengr]

Interestingly, there was another program that used the landing skids but a more conventional gliding parachute rather than the Rogallo wing, run out of Houston, that I had never heard of.  "GEMINI LAND DEVELOPMENT LANDING SYSTEM PROGRAM", https://ntrs.nasa.gov/api/citations/19670009949/downloads/19670009949.pdf

[Blackstar]

Interestingly, there was another program that used the landing skids but a more conventional gliding parachute rather than the Rogallo wing, run out of Houston, that I had never heard of.  "GEMINI LAND DEVELOPMENT LANDING SYSTEM PROGRAM", https://ntrs.nasa.gov/api/citations/19670009949/downloads/19670009949.pdf

Yes, that's generally been referred to as the parasail test program. I have some information about that in my part 3. I have a few of the photos you see in the back of that report. I wish I had more of them, because there are some cool photos.

One thing that confused me for awhile was that if you look at the photos of the "parasail," it doesn't look like the current design for parasails. The current parasail design is more rectangular. What they started out with during that test program was more of a canopy/bowl shaped parachute with vents cut in one side. That allowed the air to vent out in a specific direction, so that it fell more diagonally than vertically.

[ccdengr]

One thing that confused me for awhile was that if you look at the photos of the "parasail," it doesn't look like the current design for parasails.

Similar to the Pioneer Para-Commander from the 60s.  https://www.parachutehistory.com/round/pc.html Pioneer also made the Gemini parasail.

Most chutes now are ram-air parafoils.

[laszlo]

Parachutes were a well-understood and developed technology back then. They didn't require much in the way of ancillary equipment and power. Although electrically triggered, most of the actual energy to deploy them was

SNIP

Compare this to the paraglider system which needed its structure inflated from an onboard gas source, the

...You noted that the parachute is relatively simple in construction and operation vs. the paraglider. Something I would add is that it undoubtely weighed a lot less....

Yes, that and the impact on the systems engineering is exactly what I was alluding to in my penultimate paragraph. That fact that it keeps happening over and over again in programs decades later is sometimes a bit discouraging, but I guess it goes to show that each generation has to figure it out for themselves instead of learning from the mistakes of their predecessors.

[leovinus]

Interestingly, there was another program that used the landing skids but a more conventional gliding parachute rather than the Rogallo wing, run out of Houston, that I had never heard of.  "GEMINI LAND DEVELOPMENT LANDING SYSTEM PROGRAM", https://ntrs.nasa.gov/api/citations/19670009949/downloads/19670009949.pdf

Yes, that's generally been referred to as the parasail test program. I have some information about that in my part 3. I have a few of the photos you see in the back of that report. I wish I had more of them, because there are some cool photos.

One thing that confused me for awhile was that if you look at the photos of the "parasail," it doesn't look like the current design for parasails. The current parasail design is more rectangular. What they started out with during that test program was more of a canopy/bowl shaped parachute with vents cut in one side. That allowed the air to vent out in a specific direction, so that it fell more diagonally than vertically.

A quick look through the known list of NTRS documents based on paraglider, parasail, parawing gives NTRS document ids like the ones below. To be clear, there are many more matching titles. Attached for reference, the "resume" 19660017784.

paraglider

19640047358 ,Flying qualities of the gemini paraglider recovery system, 1963,

parasail

19650057311 ,Development of the parasail parachute as a landing system for manned spacecraft, 1964,

parawing

19620000061 ,"AN ANALYTICAL INVESTIGATION OF THE LOADS, TEMPERATURE, AND RANGES OBTAINED DURING THE RECOVERY OF ROCKET BOOSTERS BY MEANS OF A PARAWING", 1962,
19630002411 ,EXPERIMENTAL AND THEORETICAL STUDIES OF THE EFFECTS OF CAMBER AND TWIST ON THE AERODYNAMIC CHARACTERISTICS OF PARAWINGS HAVING NOMINAL ASPECT RATIOS OF 3 AND 6", "1963-01-01", archive.org
19630003915 ,EXPERIMENTAL INVESTIGATION OF THE DYNAMIC STABILITY OF A TOWED PARAWING GLIDER MODEL, 1963,
19630032632 ,AERODYNAMICS OF THE PARAWING, 1963,
19640001327 ,Free flight investigation of the deployment of a parawing recovery device for a radio- controlled 1/5-scale dynamic model spacecraft, 1963,
19650025663 ,The development of parawings for use as recovery systems", "1964-01-01", archive.org
19650076556 ,Parawings for astronautics, 1963,
19660017784 ,Resume of recent parawing research", "1965-01-01", archive.org
19670019428 ,Low-speed tests of an all-flexible parawing for landing a lifting-body spacecraft", "1967-06-01", archive.org

[WallE]

In the early 1960s the engineers thought that they had a solution, a radical new type of parachute-like device known as a Rogallo Wing. The only problem was that nobody knew if it worked. That’s why NASA began an extensive test program. It did not always go well.

The Soviet/Russian space program of course always did land touchdowns and it did create a lot of technical challenges which was why on Vostok the cosmonaut had to be launched out of the capsule with an ejector seat during descent and later spacecraft had retrorockets in the capsule to slow the rate of descent. Russia in such fairness also had vast expanses of nearly empty land a spacecraft could touch down on while the United States did not quite have so much empty space, only some areas in the Western US perhaps being empty enough to be suitable to land in.

Where Gemini could have touched down on land is anyone's guess; the flights used 28 or 32 deg inclinations and that would give you a relatively limited area of the US to land in, mostly in the Southern states. I suppose different inclinations could have been used if they desired a bigger landing area.

The photoreconnaisance programs had a somewhat similar issue, the film capsules had to be dropped over water and grabbed in mid-air by a recovery aircraft (and those were really undesirable to land in a populated area) whereas the Soviets could just drop theirs in the vast empty expanse of land they had.

[Blackstar]

I plan on posting all my paraglider material in this thread. Here are some of the early reports on it. These were produced by contractors bidding to get the contract to do the early tests. North American got the contract, but Ryan and Goodyear wanted to get it.

[Blackstar]

Here is Tow Test Vehicle 2 during a Mojave Desert test. I suspect that is a dummy in the cockpit not a test pilot, because the fingers look stiff.

TTV1 is in the Smithsonian. TTV2 is in Leicester, England.

[Blackstar]

And here is one of the parasail tests. This is the El Kabong I test vehicle, which was adapted from one of the boilerplates used for the earlier paraglider tests. This test was in Texas, whereas the paraglider tests were in the Mojave Desert.

[WallE]

Alright that makes sense, they would have tried to land in the desert Southwest or somesuch since if you were at 32 deg inclination in orbit the furthest north you could land in is central Texas.

[Blackstar]

Alright that makes sense, they would have tried to land in the desert Southwest or somesuch since if you were at 32 deg inclination in orbit the furthest north you could land in is central Texas.

Don't attribute a plan here. I don't think there really was. What happened was that the paraglider research program was managed out of Edwards. The later parasail research program was managed out of Houston. I think they picked West Texas because it was closer.

[Jim]

The photoreconnaisance programs had a somewhat similar issue, the film capsules had to be dropped over water and grabbed in mid-air by a recovery aircraft (and those were really undesirable to land in a populated area) whereas the Soviets could just drop theirs in the vast empty expanse of land they had.

Hence the PRIME program.

[Blackstar]

The photoreconnaisance programs had a somewhat similar issue, the film capsules had to be dropped over water and grabbed in mid-air by a recovery aircraft (and those were really undesirable to land in a populated area) whereas the Soviets could just drop theirs in the vast empty expanse of land they had.

Hence the PRIME program.

Yup. But I could never get truly definitive info linking PRIME to satellite reconnaissance. There's a memo by the DNRO mentioning that USAF was working on PRIME, but no clear indication that anybody in NRO stated that it would fulfill a requirement. It was a nifty little program, however. See this:

https://www.thespacereview.com/article/3446/1

[Blackstar]

I'm going to use some screencaps from some videos in my article. Here is a neat one:

[Blackstar]

And this one, about the Tow Test Vehicle 1 in the National Air and Space Museum: