The Proton series of rockets are one of the longest running in the history of spaceflight. They made their debut back in 1965 when the first of them was used to launch the Proton series of scientific satellites which were super high energy cosmic particle detectors. Since then they’ve become the mainstay of the Russian space program being used for pretty much everything from communication satellites to launching the Soyuz and Progress crafts that service the International Space Station. In that time they’ve seen some 384 launches total making it one of the most successful launch platforms to date. However that number also includes 44 full and partial failures, including a few high profile ones that I blogged about a couple years back.
Unfortunately it appears that history has repeated itself today with another Proton crashing in a rather spectacular fashion:
To put this in perspective there’s been about 37 total launches of the Proton rocket since 2010 with 5 of them being either partial or full failures. This isn’t out of line with the current failure rate of the program which hovers around 11% but 4 of those have happened in the last 2 years which is cause for concern. The primary problem seems to be related to the upper stage as 3 of the recent 4 have been due to that failing which can be attributed to it being a revised component that only came into service recently. This particular crash however was not an upper stage failure as it happened long before that component could come online, indicating the problem is with the first stage.
The reasoning behind why this crash ended so spectacularly is pretty interesting as it highlights some of the design differences between the American and Russian designs. Most American launchers have a launch termination system built into them for situations like this, allowing the ground crew to self destruct the rocket mid air should anything like this happen. Russian rockets don’t have such systems and prefer to simply shut down the engines when failures like this happen. However for the safety of the ground crew the engines won’t shut off prior to 42 seconds after launch which is why you see this particular rocket continuously firing right up until it tears itself apart.
Additionally the Russian rockets use a rocket fuel mixture that consists of Unsymmetrical Dimethylhydrazine and Nitrogen Tetroxide. When these two compounds mix together they react in a highly energetic hypergolic reaction, meaning they burn without requiring any ignition source. This is where the giant orange fireball comes from as the aerodynamic stresses on the craft ruptured the fuel and oxidizer tanks, causing them to come into contact and ignite. Other rocket designs usually use liquid oxygen and kerosene which don’t automatically ignite and thus wouldn’t typically produce a fireball like that but the launch termination systems usually ensure that all the remaining fuel is consumed anyway.
Needless to say this doesn’t reflect well on Russia’s launch capabilities but it should be taken in perspective. Whilst the recent failure rate is a cause for concern it has to be noted that the R-7, the rocket that launches both the Progress and Soyuz craft to the ISS, has experienced 0 failures in the same time frame with a very comparable number of launches. It’s quite likely that the failure isn’t part of a larger systemic issue since we’ve had multiple successful launches recently and I’m sure we’ll know the cause sooner rather than later. Hopefully Russia can get the issue resolved before too long and avoid such dramatic incidents in the future.
Russia’s space program has a reputation for sticking to ideas once they’ve got them right. Their Soyuz (pronounced sah-yooz) craft are a testament to this, having undergone 4 iterations since their initial inception but still sharing many of the base characteristics that were developed decades ago. The Soyuz family are also the longest serving series of spacecraft in history and with it only having 2 fatal accidents in that time they are well regarded as the safest spacecraft around. It’s no wonder then that 2 of the Soyuz capsules remain permanently docked to the International Space Station to serve as escape pods in the even of a catastrophe, a testament to the confidence the space industry has with them.
Recent news however has brought other parts of the Russia space program into question, namely their Proton launch stack. Last week saw a Proton launched communications satellite ending up in the wrong orbit when the upper orbital insertion model failed to guide it to the proper geostationary orbit. Then just this week saw another Proton launched payload, this time a Progress craft bound for the ISS, crashed shortly after launch:
The robotic Progress 44 cargo ship blasted off atop a Soyuz U rocket at 9 a.m. EDT (1300 GMT) from the central Asian spaceport of Baikonur Cosmodrome in Kazakhstan and was due to arrive at the space station on Friday.
“Unfortunately, about 325 seconds into flight, shortly after the third stage was ignited, the vehicle commanded an engine shutdown due to an engine anomaly,” NASA station program manager Mike Suffredini told reporters today. “The vehicle impacted in the Altai region of the Russian Federation.”
Now an unmanned spacecraft failing after launch wouldn’t be so much of a problem usually (apart from investigating why it happened) but the reason why this particular failure has everyone worried is the similarity between the human carrying Soyuz capsule and the Progress cargo craft that was on top of it. In essence they’re an identical craft with the Progress having a fuel pod instead of a crew capsule allowing it to refuel the ISS on orbit. A failure then with the Progress craft calls into question the Soyuz as well, especially when there’s been 2 launches so close to each other that have experienced problems.
From a crew safety perspective however the Soyuz should still be considered a safe craft. If an event such as the one that happened this week had a Soyuz rather than a Progress on top of it the crew would have been safe thanks to the launch escape system that flies on top of all manned Soyuz capsules. When a launch abort event occurs these rockets fire and pull the capsule safely away from the rest of the launch stack and thanks to the Soyuz’s design it can then descend back to earth on its usual ballistic trajectory. It’s not the softest of landings however, but it’s easily survivable.
The loss of cargo bound for the ISS does mean that some difficult decisions have to be made. Whilst they’re not exactly strapped for supplies at the moment (current estimates have them with a year of breathing room) the time required to do a full investigation into the failure does push other resupply and crew replacement missions back significantly. Russia currently has the only launch system capable of getting humans to and from the ISS and since they’re only a 3 person craft this presents the very real possibility that the ISS crew will be scaled back. Whilst I’m all aflutter for SpaceX their manned flights aren’t expected to come online until the middle of the decade and they’re the most advanced option at this point. If the problems with the Proton launch stack can be sorted expediently then the ISS may remain fully crewed, but only time will tell if this is the case.
The Soyuz and Progress series have proven to be some of the most reliable spacecraft developed to date and I have every confidence that Russia will be able to overcome these problems as they have done so in the past. Incidents like this demonstrate how badly commercialization of rudimentary space activities is required, especially when one of the former space powers doesn’t seem that interested in space anymore. Thankfully the developing private space industry is more than up to the challenge and we’re only a few short years away from these sorts of problems boiling down to switching manufacturers, rather than curtailing our efforts in space completely.