Validation of Astronaut Parafoil Deployment Locations

With the rise of commercial manned high altitude, and low earth orbit scientific research, the explorers who venture here are in need of sufficient emergency technology and training. Such technology has limited availability and little is known on its technical performance especially when studying high altitude parachute egress systems.

I proposed to research the engineering and human factors associated with high altitude emergency egress parafoil handle deployment locations. Standard parafoils are operated through handles located on the bottom or sides of the parafoil container. Pressure suits utilized at operating pressure to maintain appropriate life support at altitudes above 50,000ft MSL restrict its user to a factor that can immobilize movement.

With these aspects in mind I hypothesized that in an emergency egress situation, where an astronaut or similar high altitude explorer experiences an off nominal bail out, they could have difficulties deploying a stabilizing drogue or a main parafoil based off of the systems handle location. This situation could result in catastrophic deployment failure of life saving equipment.

We initially believed that the best location for an emergency parafoil deployment handle for high altitude exploration is located on the right exterior thigh or left anterior wrist depending of the egress body position. In order to test this hypothesis we planned on utilizing the NASA task load index and biometric sensors to determine the human factors restraints and significance for the two different deployment locations.

In a full pressure suit we planned on determining the difficulties in reach, strain and stress. We will be able to extrapolate the most effective emergency handle deployment location in a safe but effective test environment.

The project will used equipment provided by Pacific Spaceflight (pressure suit and life support system) and Kapowsin Air Sports (parafoil container). In order to test the appropriate aerodynamics, a vertical wind tunnel is also necessary. Our team will test these deployment locations over the course of 30 minutes of free fall flight. As a free fall time ranges from a standard 30 seconds to possible high altitude egress for 10 minutes, the time frame allowed is more than sufficient in testing and recording the data needed. The research teams experience with high altitude flight, research, and egress gives us the adequate baseline to build the study.

Originally, I proposed to test astronaut parafoil deployment locations of a pressurized subject to determine the best user interface. If a high altitude explorer was unable to connect successfully with a deployment handle during an emergency egress scenario the consequences could be fatal. I hypothesized that the location of the left wrist or right thigh would be the most effective situation for the deployment handles. By taking skydiver vitals and written feedback we would be able to compile a case study in which the results could help determine the future of safety in high altitude exploration.

For reference, a normal parachutist rig deploys a main handle at the bottom of the parachute container, also known as BOC, with a reserve below the chest strap. Please reference figure 1.1 for the main deployment handle and the cutaway handle locations. It came quite apparent that the parachute system needed for a high altitude egress would have considerable differences from a standard rig. After reaching out to professional rig manufactures and professionals, we decided to swap out our original system for what is known as an MC4. This is a military type parachute rig that would allow for more weight to be carried (such as a life support system). Below in Figure 1.2 you can reference differences in the parachute handle deployment locations to Figure 1.1.

Once the MC4 system and flight time were established we proceeded to maintain meetings with the pilot and flight team. Through our discussions we determined the most appropriate course of action forward and determined the need to tailor my original hypothesis.

It was understood that parachute deployment handles were attached to cables that connected to release pins in the container which deployed the parachutes. It was not understood that these long connections are cause for malfunction and thus the shorter the cable lead the safer the system should theoretically be. With the guidance of the skydiving test pilot it was determined that the originally hypothesized locations would cause an unneeded amount stress to the deployment system. Even if the wrist and thigh handle locations were more desirable for a suited egress, the potential failure of the cable system could put the entre unit in jeopardy.

We took this into consideration as the spirit of the study is to uncover the best location for deployment handle location. The team then agreed that three locations close to the container should be tested: a shoulder strap handle (notated as chest), a waist location (notated as waist), and a standard bottom of container location (notated as BOC). I then hypothesized that the waist location would be the most effective as it was closest to the original thigh location I originally outlined.

Using the NASA task load index we aimed to collect pilot input on use and location of parafoil deployment handle. The Hart and Staveland’s NASA Task Load Index (TLX) method assesses work load on five 7-point scales. Increments of high, medium and low estimates for each point result in 21 gradations on the scales.

The pilot skydiver utilizing the suits first filled out the index based off of a control flight. This control flight was flown without any spacesuit gear but with a mock MC-4 military parachute. Each deployment handle location was tested by the pilot and the index was completed after each flight. Once the 3 control flights were completed the flight subject suited up to fly the pressure suit.

NASA task load index questions:

  • How mentally demanding was the task?
  • How physically demanding was the task?
  • How hurried or rushed was the pace of the task?
  • How successful were you in accomplishing what you were asked to do?
  • How hard did you have to work to accomplish your level of performance?
  • How insecure, discouraged, irritated, stressed, and annoyed were you?

*No biomedical sensors were utilized to gauge stress levels as the they were not recording data effectively at the time of the research

Gear Used:

MC-4 parachute only

-1 location practice pull, three times

-1 deployment location tested per 1 minute flight

Gear used for control flight

-MC-4 parachute mock harness

-harness weight

-Cookie helmet

-Ifly flight suit (low drag)

Gear used for suited flight

-MC-4 parachute mock harness

-Pacific spaceflight pressure suit

-13cf 32% O2 tank

-Pacific Spaceflight Life Support System

Pilot Qualification:

Name: Josh Sattler

Years in skydiving: 11

Jumps: 8300

World Records: 1

State Records: 3

Ratings: AFF instructor, USPA Coach, Tandem Instructor, Pro status, 48 hours freefall badge

Once the pilot was suited up and ready for flight he was taken into the flight tunnel. Tunnel velocity was brought up to provide lift on the subject and he commenced the handle location testing. As mentioned before the pilot did this initially with out the suit on in order to build a base line of reference.

Pictures to the right show the pilot testing the suit in flight to get a feel for the difference in stability and difficulty of movement. When the pilot was comfortable, he moved through the progression of deployment handle locations that were being tested.

s we were unable to collect any biometric data from the pilot we opted to collect his qualitative feedback. His answers below can be summarized as the chest handle location being the most effective. These were notes taken by me and are not direct quotes.

  • Chest handle location: seemed to be easiest to manage out of the three tested.
  • The mc-4 needs to be adjusted properly so as to avoid overtightening (i.e. the belly band needs to be loosened to compensate for the inflated size of the suit)
  • Overall flying was easy. The main difficulty was being able to keep the extremities on (gloves fitted to hands and feet kept in boots). Due to the expanded nature of the suit once pressurized it falls off your hands which makes control and use of handles ineffective. This is strictly a size issue and not a suit design remark, however.
  • Walking and controlling the suit was easy even when beginning to pressurize. (not at operational pressure)
  • Arching at 1 psi will be easier once the belly band is adjusted to pressure
  • Better leg pads would also lead to a higher comfort level.
  • The chest mounted 02 bottle was secure and in a good spot. I had confidence I could adjust the tank’s valves if necessary.
  • Overall it was a great experience and something I was able to do effortlessly besides the size limitations and adjustments on the belly band.
  • If I had to fully locate and fully deploy a handle, I can see how it would be more difficult.

It is useful mentioning that the pilot’s responses were taken after all flights were completed. One complication that I do not understand is how the pilot’s response of how “easy” the tasks were equate to the data gathered throughout the flights. Below you will see the comparative chart of the pilot’s task load index through each of the three flights.

As a reminder, each task load question had a drawn scale from low to high that was then designated a numerical number. Very low started at 1 and very high ended the scale at 21.

ll task load questions had a cumulative sum of 126 as the most difficult overall score. In all cases the lower the number the better the pilot felt he preformed the task. In the even that the pilot was not able to perform the task the maximum total scale of 126 was selected as a default to demonstrate the high level of difficulty of the task.

Below you can reference the final results of the testing. Starting at the left of the chart we can visualize the control locations: chest, waist, BOC. Moving to the right we then reference the suited attempts, then end with the higher pressurized suited attempts (1 psi or over). Specific flight responses available in the Pilot Task Load answers after each flight section below.

We initially notice the same stair shaped progression of difficulty in each of the three testing scenarios. The chest location was the best situation in all circumstances, with the waist location in second and BOC last.

Looking closer we see what I believe is an anomaly, the data shows that the suited test flight for all locations were easier for the pilot to access than in the control scenario. If taking the pilots flight comments into consideration, we could conclude that flying with a space suit makes it easier to locate all deployment handle locations.

I believe that this misleading extrapolation can be explained by the inability to run multiple scenarios with the subject over a greater period of time. With a suit being naturally more restrictive, causing a lack of pilot visibility through the helmet and visor, and while taking away dexterity it seems impossible to me that being suited could be easier than the control flights. With the pilots lack of experience in a suit and with the Task Load scales, I think that if we had the funds to test over a longer period of time the pilots results would have shown that flying in the suit is more difficult.

Once we stepped up the pressure in the suit to above 1 psi, we see a dramatic change in difficulty. As a suited pilot in any high altitude emergency egress scenario you would be pressurized to over 1 psi (closer to 4 psi) to maintain what is known as useful consciousness. We can see that even in this 1 psi scenario that the easiest handle to operate is at the chest.

In conclusion, even with the changes in testing and the data recovered we can determine that the chest location is one of the easiest positions to place an emergency parafoil deployment handle for reach in a pressurized suit at high altitudes. It is also the easiest location to reach for a non suited pilot.

After further discussions with the pilot and other flight team members we believe that an automated parafoil release with a reserve manual chest release handle would be the preferred method of parachute deployment for pressurized suit egress. Having an automated system allows the pilot to focus on maintaining stability while the chute is deployed. This could also be beneficial if the pilot becomes unconscious during the freefall back to Earth or on another planet. At lower altitudes the pilot would have ample time to stabilize and could still reach the manual deployment handle at the chest.

Full data will be published online at a later date.