The Sep 2010 issue of IEEE Spectrum has a nice example of how determination beats technology. The article is “A Digital Soyuz” by James Oberg, and discusses how the Russians have upgraded their main manned spacecraft. They’ve replaced the main flight computer, the Argon-16, and five analog monitoring and telemetry systems with a single digital system, the TsVM-101. The Argon-16 has been in use for over 35 years (!). It contains 6 KB of RAM and can do 200 K adds/second. That’s K, not M or G. It weighs 70 kg, but oddly enough draws about as much power as a PC, 280 W.
“Backwards Russians,” you might think. “No wonder they lost their empire.” I take away the opposite message. They built something that worked and then stopped screwing with it. This machine has triple redundancy – three copies of every subsystem that vote as to who’s correct. It uses rad-hard TTL circuits. It has never failed in flight.
As of March 2010, the Soyuz series has had 104 flights (compared to 114 for the Shuttle), and has lifted 276 people into space (723 for the Shuttle). Its last failure was in 1971 on Soyuz-11 when the crew died on re-entry from loss of pressure. The Shuttle’s last failure, of course, was when Columbia broke up on re-entry in 2003. So that’s 39 years without a failure for Soyuz, and 7 for the Shuttle. The Shuttle only has a couple of flights left, so Soyuz will be the only way to get to the International Space Station for some time.
So why are they upgrading Soyuz now? Several reasons:
- The new computer is lighter than the Argon-16 and the analog systems, increasing cargo capacity by 70 kg.
- The analog systems were harder to calibrate and test, which made it take longer to prep the craft. It’ll be flying more often when the Shuttle stops.
- It only needs one pilot instead of two, so two non-pilot mission specialists can go up instead of one.
The only upcoming contender for US manned launches is the Dragon spacecraft from SpaceX Corp. It’s due to have its first launch this year, but it’ll be unmanned. SpaceX has had 3 failures in 6 launches total. The parachutes did not open on reentry for first Falcon 9 launch, but they called it a success anyway. That kind of spin is not encouraging. Perhaps the hyper-tech founder of SpaceX, Elon Musk, could learn a thing about reliability from the stodgy Russians.
[Juicy gossip addendum – Musk divorced his wife Justine in 2008, leaving her with 5 kids. He then married a much younger actress, Talulah Riley. He’s 39 and she’s 25, which just fails under the XKCD creepiness rule – you shouldn’t date anyone younger than your age divided by 2 + 7. He and Justine are wrangling in court, of course, but one thing she wants is a Tesla Roadster, glacier blue.]