The Proton rocket, heavy-lift workhorse of the Russian fleet, has finally returned to flight. The mission was a commercial one, sold through International Launch Services (a joint venture of RSC Khrunichev and Lockheed Martin), and carried the Echostar 21 commercial commsat to geosynchronous transfer orbit. The launch was fully successful, which I’m sure was a bit of a relief after the year-long grounding extended by a frustrating series of delays: first it was grounded to study concerns with the Briz-M upper stage, and then it was grounded further when contamination found in the engines revealed a much larger pattern of fraud within the engine manufacturer, Voronezh Mechanical Plant. Fallout from that included the humiliating order to turn Voronezh management over to their rival, NPO Energomash, which has been tasked with cleaning up the organization so that this does not happen again.
It’s good to see the old workhorse back in operation again. There are four more Proton flights scheduled for 2017, as it works to clear out the backlog.
The investigation went deeper than previous ones, since the previous hadn’t actually resulted in any improvement, and what they found was surprising to me. It wasn’t just quality control issues in manufacturing, as had previously been suspected; there are honest-to-gosh design defects in both the Briz-M upper stage for the Proton, and the upper stage of the Soyuz 2-1a.
The Soyuz 2-1a is a new model of the venerable R-7 family. Being quite new, it’s perhaps unsurprising there’s a problem, but what’s interesting is that the design flaw only shows up with the Progress as payload. (Presumably, it could also happen with Soyuz, which shares its service module entirely with Progress.) This explains why it never had a problem on any of its other flights, but the defect must be fixed before it can carry Soyuz or Progress into orbit.
The Proton defect is a bit more worrisome, because it’s been in the system for decades without anyone noticing — despite multiple failures with similar characteristics and multiple investigations. A small vernier engine used for steering the vehicle during third stage flight has a design defect which makes it extremely easy to unbalance. And when it becomes unbalanced, it experiences increasingly violent vibrations until it undergoes what rocket scientists dryly refer to as an “unscheduled disassembly”. The good news is that existing engines can be reworked with a different rotor shaft in their turbopumps to prevent the problem happening again. Also, it’s back to flight now, having been cleared for all non-Progress/Soyuz flights, placing a military satellite (possibly a Kobalt or Persona spy satellite) into orbit:
So, good on you, Russia, for finding these defects! Hopefully the design change and rework will do the trick, and keep Proton flying safely. Alternately, I’d be happy with them replacing it; Proton’s one of the last flying launch vehicles to use hydrazine and nitrogen tetroxide in the first stage. Nasty stuff to release into the atmosphere.
UPDATE: While the investigation is only beginning, at present it appears that a fault in steering engines may have been to blame. This would a four-nozzle vernier engine. During third stage flight, a rocket is going very fast — approaching orbital velocity — and only slight deviations from its trajectory could put enormous aerodynamic strain on the vehicle. Meanwhile, MexSat-1’s insurance policy is paying for the entire cost of the spacecraft. Lastly, I have a correction — I wrote that the third MexSat would be launching aboard Ariane V, but I had the wrong A*V vehicle. The first one went up on Ariane V, but the third (Morelos 2) will be going up on Atlas V.
Proton-M was scheduled to launch MexSat-1 “Centenario”, a Mexican geosynchronous commsat, from Baikonur Cosmodrome today. The initial launch looked fine, but then something went catastrophically wrong during operation of the Briz-M third stage. Proton-M has had a particularly bad wrong. Out of 43 launch attempts in the past five years, six have been catastrophic failures, and two ended in useless orbits. The payload and upper stage are believed to have reentered and impacted in the Chita region of Russia, near Mongolia, although signs suggest it broke up very high and so pieces may be relatively small. This flight was managed by International Launch Services, a collaboration between Lockheed Martin and RSC Khrunichev, which sells Proton and Atlas V commercially.
“Centenario” is one of a set of three satellites purchased by Mexico from Boeing and built in the United States. The first one launched on Ariane V and has gone into service, while the third is scheduled to also fly on Ariane V.
Everything looks okay in this video, but it likely perished not long after: