The Soyuz Failure and Emergency Return

Proponents of manned space flight have looked forward to the day when space travel will be as routine as getting on a bus in Toledo to go to Chicago.  You don’t normally see national headlines when a bus breaks down, but when the Russian Soyuz rocket taking an American and a Russian astronaut to the International Space Station (ISS) last week suddenly failed and the astronauts had to be rescued by an automatic emergency system, it made the New York Times and other media outlets around the world.  So we aren’t quite there yet, and it will be some time before we can even get anyone else up into orbit.

First, the failure.  On Thursday, Oct. 11, astronauts Aleksei Ovchinin and Nick Hague took off from the Baikonur Cosmodrome on a Russian Soyuz rocket.  The first stage consists of four detachable engines on four sides of the central second-stage rocket.  Two minutes into the launch, the four first-state engines normally eject themselves and the second stage lights up to continue the flight into the orbital range of the ISS.  But according to the website www.extremetech.com which quoted Russian head of human spaceflight Sergei Krikalev, experts suspect that something went wrong with one of the first-stage engine ejection systems.  One of them may have incompletely separated and collided with the second stage.  At any rate, enough damage was detected that an automatic abort system went into action, separating the capsule containing the two astronauts from the second stage and sending it in an earthbound trajectory that produced up to 6 Gs on the pair, twice what they experience during launch.  A parachute automatically deployed, and instead of spending six months in space in the ISS, Hague and Ovchinin ended their flight only a few minutes after launch in the desert-like steppes of Kazakhstan, where they were rescued by ground crews without further incident.

We can thank the Russian engineers who designed and installed the safety systems 35 years ago in what is now a pretty old but well-understood and reliable rocket system.  Russia has had its share of space-related accidents, dating all the way back to 1967 when a parachute on the Soyuz 1 flight failed to open, causing the death of astronaut Vladimir Komarov when his capsule crashed to the ground too fast.  Simplicity and reliability seem to be watchwords with the Russian space program, and while the two astronauts are no doubt disappointed that their flight was cancelled, so to speak, they are at least alive and well to talk about it.

The current residents of the ISS are in no immediate danger, as unmanned resupply rockets are still operational and they have an emergency escape capsule at hand should something require them to leave for Earth in a hurry.  But the failure of the only current means of human access to the ISS has put a big hold on the station’s plans, and on manned spaceflight in general.

In possibly a year or so, both Boeing and SpaceX hope to begin manned flights of their own, ushering in a new era of spacecraft built by private firms dedicated to the purpose, rather than the cumbersome government public-private partnerships that have up to now been responsible for all manned space travel.  But those companies’ rockets are not ready, and if recent history is any guide, they may not be ready for several years yet. 

Unlike the race to the moon, which was basically the Cold War between the old USSR and the U. S. carried out by peaceful means, private space firms are in competition only with other firms.  So it would be better to err on the side of prudence rather than rush into manned spaceflight only to have your latest creation blow up and kill people.  The rewards awaiting companies that make it first into space with humans are by no means certain, other than the glory of the thing.  But glory is hard to take to the bank. 

Tourism is one way to make money with space, but no one believes that will support the whole enterprise by itself.  And tourists have an obstinate prejudice against running a high risk of ending up as space junk or worse, so the safety record of space flight will have to be significantly improved before anything like mass tourism can come about. 

Regarding re-crewing the space station, currently the Soyuz is the only show in town, and if the accident investigation isn’t wrapped up satisfactorily by the end of 2018, we might see a situation in which the ISS crew comes home and the empty station is piloted remotely until Russian engineers are confident in launching more astronauts with the Soyuz.  Published schedules for the ISS through 2020 do not include any plans for using rockets other than Soyuz to transport astronauts to the station, so SpaceX’s manned flights will presumably be orbital demonstrations independent of the space station itself.

If manned space flight were completely routine, it wouldn’t attract the attention and excitement it does.  In my own field of engineering, some of the best students have ambitions to get involved in private space enterprises, and they go with my blessing.  But the period we are in now may be compared to where the aviation industry was in around 1920.  Flying was still regarded as an exotic and dangerous sport, and it was not yet clear how anyone would make any serious money at it. 

We can hope that the cause of the Soyuz failure can be identified and fixed soon enough that we don’t have to depopulate the ISS, and that transportation to the station can go back to its desirable no-headlines mode.  But we can also expect that the upcoming launches of private manned space rockets will get tons of publicity, even if they’re successful.  Because taking a rocket into space is still nowhere near as routine as taking a bus to Chicago.

Sources:  I referred to news reports on the Soyuz accident carried by the New York Times on Oct. 11, 2018 at https://www.nytimes.com/2018/10/11/science/soyuz-rocket.html, and also the sources https://www.space.com/42155-soyuz-abort-astronaut-nick-hague-first-interviews.html and https://www.extremetech.com/extreme/278883-russia-blames-soyuz-launch-failure-on-booster-collision.  I also referred to Wikipedia articles on a list of spaceflight-related accidents and incidents, the Baikonur Cosmodrome, and the International Space Station. 

Space Flight: A Risky Business

The commercial space flight business suffered a one-two punch last week.  On Tuesday, an unmanned rocket carrying supplies for the International Space Station and launched by Orbital Sciences Inc. failed a few seconds after launch, falling back to the launch pad and exploding to make a spectacular nighttime video that must have been shown on every TV outlet in the U. S.  It was the company's third commercial launch of a contract to supply the Space Station, whose residents will now have to wait a while longer for the next garbage pickup.  (A side benefit of the long-distance unmanned deliveries is that the Space Station folks can cram the vehicle with their trash and let it burn up in the atmosphere.) 

And then Friday, Virgin Galactic's SpaceShipTwo, manned by two experienced test pilots, broke up high above the Mojave Desert in California, killing pilot Michael Alsbury, 39, and injuring the other, Peter Siebold.  The crash scattered debris over a five-mile-long area and initiated an investigation by both Virgin Galactic and the U. S. National Transportation Safety Board which could take as long as a year.

Any time anyone is injured or killed in a space-related accident, engineers are obliged to get to the bottom of the technical whys and hows of the mishap.  But beyond the specific technical causes of these particular accidents, tragic as they were, is the question of how reliable commercial manned space flight is going to be.  And a little history can throw some light on that question.

A man named Ed Kyle maintains an extensive statistical study of space-flight launches at a website called www.spacelaunchreport.com.  He compiles both unmanned and manned flights, although in the nature of the business, the vast majority of launches are unmanned.  Bearing that in mind, we can look at a convenient summary table he provides of success rates of launches by decade, going all the way back from the infancy of space flight in the 1950s to the 2010s. 

America's first attempt to launch a satellite into orbit, the Vanguard launch on Dec. 8, 1957, was a highly publicized failure, exploding after reaching the breathtaking altitude of four feet (1.2 meters).  And overall, only about half the launch attempts by all parties in the 1950s were successful.  But aerospace engineers began climbing that long haul called the learning curve, and by the 1970s the average success rate was around 95%, where it has hovered ever since.  In the last two complete years, for example (2012 and 2013), Kyle logged 159 launch attempts and 9 failures among them, for a failure rate (for the pessimists among us) of 5.6%.  So even today, forty years after the space-rocket business reached maturity, there is about one chance in twenty that your satellite will not end up in space, but in a watery or earthy grave.

Despite all the fuss about NASA turning space flight over to commercial interests, satellite launches have been commercial transactions for decades.  And it appears that a failure rate of 5% is an acceptable level to support a generally prospering space industry.  The companies and their insurers can handle that level of failure and still accomplish what they want to do, most of the time. 

But launching cans of beans for a space station, and launching people who have paid a quarter of a million dollars for the ride (as prospective passengers in the Virgin Galactic rocket have coughed up in advance), are two different propositions.  Commercial airlines would not have many customers if it were well known that one out of every twenty flights was going to crash.  It took the business of aviation twenty years or so to be safe enough to offer commercial passenger service, but by 1930 or so the risks of commercial scheduled flights to the individual passenger were largely imaginary, and today you take more of a risk of dying on your drive to the airport than you take in the air. 

It may be harder for the space-flight engineers to drive their failure rates down to the level at which people could buy space-flight life insurance for a few dollars, like you used to be able to do for commercial aviation flights at airports.  Rocket hardware operates at the outer limits of materials science.  The engines run so hot that liquid-fueled nozzles have to be cooled continuously to keep them from melting, and the fluid dynamics of the combustion of rocket fuel is still so complex that an exhaustive, essentially complete mathematical model of a rocket in flight, including vibration modes and so on, is quite possibly still beyond our abilities.  So rocket designs are a combination of science-based modeling and engineering intuition, added to a large measure of experience of what has worked in the past.

I think it is significant that the Virgin Galactic flight was using a different type of fuel than they had used in previous flights.  Such a major change, even if tried out on the ground with similar hardware, can lead to unpredictable results, and may turn out to have contributed to the disastrous crash of SpaceShipTwo.  Rocket engineers, at least the successful ones, tend to be highly conservative in their designs.  Anyone who has seen both an old V-2 rocket engine in a museum and the massive Apollo engines used to launch men to the moon can see that Wernher von Braun found something that worked at Peenemunde, Germany in the 1930s, and stuck with it all the way through the 1960s. 

Such conservatism is increasingly rare among engineers in general today, influenced by innovations in hardware and software which happen so fast that you can squeeze an entire product life cycle, from introduction to obsolescence, into six months.  But the adage "if it ain't broke, don't fix it" applies in spades to space travel.  And as we find out in the coming months what caused SpaceShipTwo's failure, we may find that experimenting with a different fuel was a bad idea. 

Unless we colonize the Moon or Mars to a great extent, space travel will always be an exotic, low-volume business, like tours to the Antarctic are today.  And it is by no means clear to me that even the super-rich will be willing to take the kind of risks that simple statistics tell us space travel entails—at least, not for quite a while yet.

Sources:  Ed Kyle maintains his Space Launch Report at http://www.spacelaunchreport.com.  I referred to an article carried by the BBC on the Virgin Galactic disaster at http://www.bbc.com/news/world-us-canada-29869070

and by www.space.com on the Orbital Sciences launch failure at http://www.space.com/27615-antares-rocket-explosion-timeline.html.  I also referred to the Wikipedia article on the Vanguard (rocket).