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Same reason anyone else does tests: Find potential and actual issues earlier than in production. The static fire they were doing is sort of a short integration

by ygra 10y ago

Same reason anyone else does tests: Find potential and actual issues earlier than in production. The static fire they were doing is sort of a short integration / smoke (pun not intended) test whether the rocket as a whole (whether the payload is attached already depends on the customer; it reduces time between test and launch, though) works properly. Other tests are part of sort of a pre-flight checklist directly before launch and there have been launch scrubs due to issues at that point already. Every single engine is also fired for the full duration of the flight prior to installation in the rocket. There's a lot of testing, both in isolation and in integration with other components. The risk of the rocket exploding should actually reduce with each test. Note also that in this case the malfunction was most likely with the pad equipment, not the rocket, so not doing static fires would in this case probably just have meant that you'd have an explosion at launch time one day. EDIT: The static fire is more of a test for launch procedures, apparently: “The goal of the static fire is to provide a dress rehearsal for the launch team, culminating in a three second firing of all nine of the first stage Merlin 1D engines to validate the health of the rocket.” (https://www.nasaspaceflight.com/2016/09/falcon-9-explodes-amos-6-static-fire/ https://www.nasaspaceflight.com/2016/09/falcon-9-explodes-am...) Makes sense in that the rocket itself is tested quite a bit beforehand already.

dmix 10y ago
Is launch pad designed to take a hit like this? Or do you think it would have caused a lot of damage to Cape Canaveral.
- mitchty 10y ago
  Unlikely, it wouldn't be much of a launch pad if it couldn't handle failure modes for rockets (aka bombs with a hole in one end). Compare to this Saturn V launch. https://www.youtube.com/watch?v=DKtVpvzUF1Y https://www.youtube.com/watch?v=DKtVpvzUF1Y
  - manarth 10y ago
    The video points out two of the protection features, but they wouldn't do so well with a RUD. The tower features - the hold-down arms, etc - are painted with a sacrificial paint. The idea is that it's the paint that chars and burns, rather than the tower features. Then there's the water deluge system. In the video, the rocket and exhaust is clear of the tower, and the fires are out, within 30 seconds. Neither the sacrificial paint nor the water deluge are designed to handle long-duration fires from a RUD. After a 2014 Antares rocket failure, the launchpad at Wallops Flight Facility took 1 year and $15 million to repair [1]. [1] http://www.space.com/31412-virginia-launchpad-private-rocket-launches.html http://www.space.com/31412-virginia-launchpad-private-rocket...
  - CydeWeys 10y ago
    It would be incredibly difficult to armor a launch pad to survive an explosion on-pad, so they aren't. The real solution is to have multiple launch pads (the space shuttle had three), so that if one blows up on the pad you have backups you can use until the blown up one is rebuilt. The energy released in the first few seconds of a controlled launch is not remotely comparable to the energy released by an entire rocket blowing up simultaneously. Also, with an explosion, the entire rocket, along with parts of the strongback and other structures it's attached to, become shrapnel. Superheated water exhaust is a lot easier to protect against.
- ygra 10y ago
  Launch pads usually are not built for rockets exploding on them, but as the pad itself is mostly a concrete plane it should be mostly fine. Controlled burn of the propellant, a.k.a., a launch, is obviously fine as well ;-) Facilities and other things on the pad may not like it, though. They already said that their Horizontal Integration Facility (where the rocket is put together prior to erection) is intact, as are the tanks on site. But the strongback looks mangled and may well be destroyed. It's also right beside the rocket, so the most likely casualty in such an explosion. Other pads and facilities are most likely far enough away that the only concern is debris from the explosion landing there.
- agildehaus 10y ago
  A rocket contains the energy of a mini-nuke. You could not design a launch pad to withstand an anomaly like this.
- planteen 10y ago
  This is a good question. There could be substantial damage. The Antares failure at Wallops knocked the pad out for months and took $15 million to repair. https://spaceflightnow.com/2015/10/06/workers-complete-15-million-in-repairs-to-antares-launch-pad/ https://spaceflightnow.com/2015/10/06/workers-complete-15-mi...
- CydeWeys 10y ago
  The pictures of the aftermath speak for themselves. The strongback is a mangled wreck, and all of the fuel tanks blew up. The vast majority of the launch complex, expressed in economic terms, is going to need to be rebuilt.

by ygra 10y ago

dmix 10y ago

Is launch pad designed to take a hit like this? Or do you think it would have caused a lot of damage to Cape Canaveral.

mitchty 10y ago
Unlikely, it wouldn't be much of a launch pad if it couldn't handle failure modes for rockets (aka bombs with a hole in one end). Compare to this Saturn V launch. https://www.youtube.com/watch?v=DKtVpvzUF1Y https://www.youtube.com/watch?v=DKtVpvzUF1Y
- manarth 10y ago
  The video points out two of the protection features, but they wouldn't do so well with a RUD. The tower features - the hold-down arms, etc - are painted with a sacrificial paint. The idea is that it's the paint that chars and burns, rather than the tower features. Then there's the water deluge system. In the video, the rocket and exhaust is clear of the tower, and the fires are out, within 30 seconds. Neither the sacrificial paint nor the water deluge are designed to handle long-duration fires from a RUD. After a 2014 Antares rocket failure, the launchpad at Wallops Flight Facility took 1 year and $15 million to repair [1]. [1] http://www.space.com/31412-virginia-launchpad-private-rocket-launches.html http://www.space.com/31412-virginia-launchpad-private-rocket...
- CydeWeys 10y ago
  It would be incredibly difficult to armor a launch pad to survive an explosion on-pad, so they aren't. The real solution is to have multiple launch pads (the space shuttle had three), so that if one blows up on the pad you have backups you can use until the blown up one is rebuilt. The energy released in the first few seconds of a controlled launch is not remotely comparable to the energy released by an entire rocket blowing up simultaneously. Also, with an explosion, the entire rocket, along with parts of the strongback and other structures it's attached to, become shrapnel. Superheated water exhaust is a lot easier to protect against.
ygra 10y ago
Launch pads usually are not built for rockets exploding on them, but as the pad itself is mostly a concrete plane it should be mostly fine. Controlled burn of the propellant, a.k.a., a launch, is obviously fine as well ;-) Facilities and other things on the pad may not like it, though. They already said that their Horizontal Integration Facility (where the rocket is put together prior to erection) is intact, as are the tanks on site. But the strongback looks mangled and may well be destroyed. It's also right beside the rocket, so the most likely casualty in such an explosion. Other pads and facilities are most likely far enough away that the only concern is debris from the explosion landing there.
agildehaus 10y ago
A rocket contains the energy of a mini-nuke. You could not design a launch pad to withstand an anomaly like this.
planteen 10y ago
This is a good question. There could be substantial damage. The Antares failure at Wallops knocked the pad out for months and took $15 million to repair. https://spaceflightnow.com/2015/10/06/workers-complete-15-million-in-repairs-to-antares-launch-pad/ https://spaceflightnow.com/2015/10/06/workers-complete-15-mi...
CydeWeys 10y ago
The pictures of the aftermath speak for themselves. The strongback is a mangled wreck, and all of the fuel tanks blew up. The vast majority of the launch complex, expressed in economic terms, is going to need to be rebuilt.