FAA’s Spaceflight Occupant Safety Practices Leave a Few Things Out

10 Comments

faa_logoI’ve been taking a look at the FAA’s “Draft Established Practices for Human Space Flight Occupant Safety” document since it was released, and I have to confess it has left me a bit puzzled.

It’s not the content that’s confusing; it’s actually very easy to understand. The problem has been figuring out how to make the material interesting. The document is drier than the Mojave in July.

I finally realized that the most interesting aspects are probably the things the FAA has decided are not established practices to safeguard space travelers. Like pressure suits. And launch escape systems. And defined standards to make sure occupants are healthy enough to fly.

In other words, the very things that have been baked into national space programs for more than 50 years.

Welcome to the NewSpace Age. It sure ain’t your father’s space program.

The practices — developed after a series of eight telecons between the FAA, commercial space industry and other stakeholders — cover both suborbital and orbital spaceflight. The agency, which is approaching commercial spaceflight on an informed consent basis, does not lay down any hard and fast rules. However, the practices could form the basis for future rule making.

“AST has developed this document to share our thoughts about established practices for human space flight occupant safety. Ultimately, our goal is to gain the consensus of government, industry, and academia on established practices as part of our mandate to encourage, facilitate, and promote the continuous improvement of the safety of launch and reentry vehicles designed to carry humans. The outcome of this effort may also serve as a starting point for a future rulemaking project, although AST has no plans to start a rulemaking project in the near term.”

The document identifies two “levels of care” for those involved in commercial space flights.

“First, the occupants of commercial human spacecraft should not experience an environment during flight that would cause death or serious injury. This is a low bar, below the level of comfort that most space flight participants would want to experience.”

OK, so don’t kill your high net worth passengers. That’s good thinking.

“Second, the level of care for flight crew when performing safety critical operations is increased to the level necessary to perform those operations. For example, if planned translational forces will not result in serious injuries, but the flight crew needs lower forces in order to move their arms to perform a safety critical operation, then an increased level of care is reflected in this document. Note that we have assumed for purposes of this document that each member of the flight crew is safety critical.”

Don’t incapacitate the crew members who are flying the ship. More good advice.

The document goes on for dozens of pages about how to achieve these levels of safety. Protect occupants against excessive noise, acceleration and radiation. Check. Separating redundant systems so the failure of one doesn’t disable the other. Got it. Design failure tolerance into a vehicle. Absolutely.

Failure Tolerance to Catastrophic Events

“a. The system should control hazards that can lead to catastrophic events with no less than single failure tolerance, except when redundancy adds complexity that results in a decrease in overall system safety, or when fault tolerance is not practicable as a system safety solution.

“b. When failure tolerance is not practical, such as for primary structure, pressure vessels, and thermal protection systems, an equivalent level of safety should be achieved through other means such as factors of safety, high reliability, and other design margin techniques.”

Most of the practices seem to be fairly commonsensical. Some, I’m guessing, are not.

But, as I mentioned, some of the things AST left out are the most interesting. Take spacesuits, the absence of which caused the deaths of three Soviet cosmonauts when their Soyuz 11 spacecraft suddenly depressurized prior to re-entry in 1971.

“Government human space flight experience has demonstrated that the ascent and reentry timeframes are the highest risk period for catastrophic failures. Given the hazard time to effect, having occupants wear pressure suits during ascent and reentry is beneficial to protect the occupants from a potential low pressure cabin environment.”

OK, the evidence is pretty strong that you would want pressure suits. So, what exactly is the problem?

“However, integrating pressure suits into a spacecraft design is not trivial, nor inexpensive. Because it may not be an ideal design trade in all cases, AST has not included pressure suits as an established practice. The conduct of an occupant survivability analysis is included in the document in order to identify measures, such as pressure suits, that may increase the occupants’ chance of survival in an emergency.”

So, it would be costly — especially if you’ve already designed your craft for a short sleeve environment and would have to perform an expensive retrofit. In that case, an operator might argue that the safety design of the vehicle is a better protection against sudden decompression, i.e., the “ideal design trade” explanation.

It is likely that the spacesuit optional approach will apply more to suborbital vehicles than orbital ones. NASA will almost certainly require the wearing of pressure suits for at least the launch and re-entry phases for any commercial crew services that it purchases.

Although protecting spaceflight participants and crew members from sudden pressure loss is not included in the practices, the FAA wants operators to protect them from bad air.

“Response to Contaminated Atmosphere

“In order to respond to a contaminated atmosphere, the vehicle should provide equipment and provisions to limit occupant exposure to the contaminated atmosphere such that occupants are protected from serious injuries, and safety critical operations can be performed successfully. The vehicle should:

“a. Provide breathable air and eye protection for each occupant;

“b. Provide voice communication between the flight crew and the ground crew; and

“c. Provide voice communication from the flight crew to the space flight participants.

Rationale: Fire, toxic out gassing, and chemical leaks can degrade a spacecraft’s atmosphere such that occupants become casualties due to asphyxiation, chemical burns, or eye injury. In addition, such emergencies are difficult to manage by the flight crew due to the hazard of inhalation or eye injuries. The use of a self-contained breathing apparatus, for example, can protect occupants from the hazard, and allow the flight crew to manage the emergency. The ability to communicate orally with the ground and within the spacecraft while wearing emergency gear is important to respond to the event.”

So, the FAA wants everyone to be able to breath safely, but if the pressure drops suddenly and their blood begins to boil, they’re on their own. That level of protection is more akin to flying in an airliner at 30,000 feet than in a space plane soaring above the Karman line.

My best guess is this approach will last until there is a fatal accident resulting spacecraft decompression. The Soviets redesigned the Soyuz after their accident, reducing the crew size from three to two for many years afterward. NASA also mandated full pressure suits after the Challenger accident.

The FAA also is leaving it up to spaceflight operators to do their own screening of spaceflight participants to determine if they are healthy enough to safely fly. The reason: a lack of data.

“This document does not include any medical criteria that would limit who should fly in space due to medical conditions. There is little clear statistical evidence on the actual impact of space flight on the health of an occupant with pre-existing conditions. Medical screening of space flight participants is included as a practice to inform them of risks and to ensure they will not be a danger to other occupants.”

The FAA’s most logical omission involves launch escape systems, which it says are a significant enhancement to safety on orbital systems but are not practical for all vehicle designs. That is certainly true, particularly when it comes to suborbital space planes now under development. All the orbital systems being funded by NASA under the Commercial Crew Program incorporate launch escape systems for the crew vehicles.

The other really interesting part of the document involves the established practice for flight demonstrations before taking a passenger.

“Prior to any flight with a space flight participant, the integrated performance of a vehicle’s hardware, any software, and operational procedures should be demonstrated by successfully executing a flight of the vehicle’s design reference mission,” the document states. “Further flight demonstration should be conducted for any subsequent modifications that cannot be tested at the integrated system level on the ground.”

Now, note the language there: “successfully executing a flight of the vehicle’s design reference mission.” As in a single flight. One. Un. Uno. Ein. Odin. Ichi.

NASA is taking this approach with its Commercial Crew Program. Each of the companies competing in the program has planned a single demonstration flight to the International Space Station. Providing the flight goes well, a company would be in a position to provide commercial transport services to the space agency.

The single demonstration flight makes sense in this situation. The companies are working extremely closely with NASA, with the space agency endeavoring to transfer as much of its human spaceflight expertise to the private sector. Procurement of flight services will also be done under strict Federal Acquisition Regulation (FAR) procedures.

Private reusable suborbital vehicles are being developed in a very different manner. It is almost certain that these providers will conduct more than one test flight with the profile they will use to fly paying customers. They will want to fully test out all the systems on a repeated basis before launching commercial service. Yet, the FAA is not recommending any set number of flights beyond one.

This approach illustrates the informed consent regime in which passengers acknowledge the risks they are taking in climbing aboard these new vehicles. It is a significant departure from the FAA’s approach to commercial aviation. The agency certifies commercial aircraft, a costly and time consuming process that requires thousands of hours of flight time before passengers can fly. However, the FAA will license manned commercial space vehicles, which is a much looser standard.

So, that’s my review of the FAA’s draft document on established practices. It turned out to be a bit more interesting than I thought. I hope you found it informative as well.

  • Michael Vaicaitis

    Doug, not sure I agree with all your comments:

    “FAA has decided are not established practices to safeguard space travelers. Like pressure suits. And launch escape systems. And defined standards to make sure occupants are healthy enough to fly.

    In other words, the very things that have been baked into national space programs for more than 50 years.”

    Except of course, the escape system of $196Billion Shuttle project. Which involved “escaping to the after life”. Also, not sure your use of the term “baked” is entirely in good taste.

    and:
    “Don’t incapacitate the crew members who are flying the ship. More good advice.”

    Better advice would be: under no circumstances whatsoever, ever, ever ever, let humans fly, or have any involvement at all in the control of, launching rockets or re-entering and landing spacecraft.

    “Take spacesuits, the absence of which caused the deaths of three Soviet cosmonauts when their Soyuz 11 spacecraft suddenly depressurized prior to re-entry in 1971.”

    Not quite so convinced about this one either. Seems to me, it was really a design failing of the spacecraft. Last time I looked, not many commercial airliners require passengers, and I’ll repeat that because its quite important, PASSENGERS, to wear pressure suits. Also, boat passengers aren’t required to wear deep sea diving suits. All in all, if we’re expecting and hoping against hope that humans can become a space faring civilisation, then spacecraft reliable enough not to have to wear suits 24×7 is an absolute requirement. Also, I’ve seen many films and pictures of the ISS and they don’t wear pressure suits. Wouldn’t a sudden depressurisation be catastrophic there too?.

    “OK, the evidence is pretty strong that you would want pressure suits.”

    Is it?. The Soyuz 11 detached from the Salyut 1 space station by a system of explosive bolts. Granted, in that particular case, pressure suits may? have saved them, assuming a sufficient available air supply. That said, nope, the evidence is most certainly not strong for pressure suits, in fact it is decidedly weak. It is spacecraft design faults that kill astronauts, not the lack of pressure suits.

    “NASA also mandated full pressure suits after the Challenger accident.”

    That’s because the Shuttle was a death trap due to intrinsically bad design and absolutely no escape system. Again, pressure suits may or may not have saved crew from drowning, but a designed method of escaping an exploding rocket would probably have been even better.

    “Now, note the language there: “successfully executing a flight of the vehicle’s design reference mission.” As in a single flight. One. Un. Uno. Ein. Odin. Ichi.”

    We can probably agree on this this. On the one hand, it may seem reasonable to categorise sub-orbital flight as an adventure sport, like bungie jumping or mountain climbing or cave diving. I have to admit, that propulsive launch escape systems, like those of orbital class rockets, is likely impractical if these systems are ever to be commercially practical. That said, if they are to be licensed, then they should be able to prove the reliability of their system at least into double figures before receiving a license to fly paying, disclaimer signing, passengers…IMO.

  • Douglas Messier

    Well, yes. The shuttle program has been the exception to the rule on human spaceflight in terms of abort systems. And we can see how well that worked out. Which is why it’s good that the new generation of orbital vehicles will have abort systems. And the FAA is correct, abort systems don’t work for all designs.

    My guess is the Soyuz 11 crew would have lived if they had pressure suits on. That’s what the suits are designed to do, keep people alive when there’s a decompression incident. But, they weren’t wearing them, and the valve system that let the air out was not well designed to accommodate a pressure failure in space.

    Commercial airliners have oxygen systems that can keep passengers and crew conscious and alert until the pilots can get to a lower altitude and make an emergency landing. It’s adequate in an emergency. That’s different from going up above the Karman line in a space plane.

  • Robert Gishubl

    For sea going ships they do not have diving suits but they do have life jackets and lifeboats for everyone. They also require exposure suits when operating in cold waters. Airplanse flying over water also require life jackets and life rafts for everyone.
    In a spacecraft where exposure to the outside will kill you quickly not having some personal protection is a significant departure from common practice. For suborbital I couls understand protective suit that is not a full space rated pressure suit of inovative design but I would expect something.

  • Jeff Smith

    Good reporting Doug.

  • Michael Vaicaitis

    I will agree that the airliner and sea ship comparisons are somewhat inappropriate. But then the Soyuz 11 incident is not “good” evidence for spacesuits, it’s the only evidence. And I repeat, it is evidence that spacecraft design should be scrutinised for safety design flaws before being licensed.

    “That’s what the suits are designed to do, keep people alive when there’s a decompression incident.”

    So are you, or are you not, suggesting that space station occupants should at all times wear sealed spacesuits with independent life support?. And if so, what good are space stations? and what is the point of entertaining a space faring and Martian future?. And if not, how do space stations and spacecraft differ?, such that spacecraft passengers must wear spacesuits, where as space station occupants are to be considered safe without them?.

  • Michael Vaicaitis

    “In a spacecraft where exposure to the outside will kill you quickly not having some personal protection is a significant departure from common practice.”
    There are many human activities where equipment failure means certain death. Working aboard the ISS for example, where exposure to the outside will instantly kill you, it is common practice to NOT wear spacesuits. In fact, wearing personal protection suits would be a significant departure from common practice.

  • Robert Gishubl

    Except during higher risk activities such as launch and re-entry ISS crew wear pressure suits as mentioned by Doug above. So why not for FAA licensed activities. Even if not a full space suit put more like a flight suit/pressure garment and helmet.

  • James Van Zandt

    Or even much simpler. Say, a cylindrical bag (like a sleeping bag) with a sealing ring and a bubble top on one end. A passenger stands or lies down inside, with the bubble open. If there’s a “sudden loss of air pressure”, he closes and seals the bubble, and the bag is inflated (either by a small air cylinder or a connection to an external air supply). Much cheaper than a pressure suit.

  • Douglas Messier

    No. As the FAA says, launch and re-entry are high risk periods of the mission.

  • Paul451

    In the spirit of SAFER and similar hideous backronyms – Limited Inflatable Fastenable Emergency Vacuum Exposure Safety Tube.

    But seriously, you might as well give them a basic pressure-suit. Bubble helmet, non-constant-volume joints. Not a proper EVA suit, but still something they can wear throughout the flight, even when they are just enjoying zero-g. The tube would need to go through the same safety tests as a pressure-suit, and be custom produced in small volumes, so you aren’t really saving any money with the simpler design.

    Once we’ve got a few hundred people in commercial space-stations at any given time, with every module needing a bunch of evac suits on the wall in case of emergency, then yes it makes sense to save money and use tubes (or balls, less volume), which can be quickly slipped into during a module-leak, and evac’ed through an airlock by an astronaut in a proper EVA suit during the subsequent rescue.