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.