What does a used Proton rocket look like?

Like this, apparently:


That’s the first stage of the Proton-M that launched Intelsat 31 to geosynchronous transfer orbit on June 9.  It impacted in Kazakhstan, but considerably short of the expected impact zone, which is why it wasn’t found for a while.  The Proton launch was technically successful, in that the payload was delivered to an adequate orbit, but that orbit was a bit slower than intended, and the Briz-M upper stage had to fire abnormally long to compensate for a shortened second-stage burn.  Telemetry indicates that the second stage yaw control engine shut down shortly before the end of the programmed burn, causing the remaining engines to expend extra propellant to maintain the proper trajectory, which in turn caused the stage as a whole to burn out prematurely.  But the fact that the first stage fell short suggests something went wrong in the first stage as well.  Engineers have been looking at the recovered debris and the telemetry ever since the launch, and International Launch Services has announced that the launch of EchoStar 21, scheduled for August 29, will be delayed to sometime in October to give engineers more time to evaluate the anomaly and determine whether there is any risk with proceeding.

Proton has had something of a checkered history, and its image never fully recovered from a string of accidents a few years ago.  It’s the cheapest launch vehicle in its weight class, which keeps it popular for geosynchronous commsats too large for Falcon 9 (which has nevertheless been eating into its market share).  But its a hazardous vehicle, powered by toxic unsymmetrical dimethyl hydrazine (UDMH) and furiously corrosive nitrogen tetroxide (N2O4), a hypergolic combination (that is, the two chemicals will ignite spontaneously upon contact with one another).  Watch also during launch videos for red smoke — that’s unused nitrogen tetroxide.  This, as you might imagine, is part of why Kazakhstan isn’t entirely thrilled about hosting Baikonur Cosmodrome anymore — and why Russia is working to get away from Proton with heavier variants of the kerosene-fueled Angara.  But in the meantime, this remains a very important part of the global rocket inventory, able to put massive commercial payloads into orbit at very competitive rates.


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