81–90 of 317 posts
Another amazing test flight! Can't wait for SN10. I understand they have already started the last step of construction which is fitting the Raptor engines to SN10. Should be ready to fly very soon.
You loved the quality of the explosion. Did you? Bigger the explosion, the more promising is the venture! NOT
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While the US had better tech and improved design they all tested the shit out of things before going live and then ran live tests on unmanned rockets, many of which exploded quick spectacularly. Soyuz might be safe now, but that safety was paid for by many near-misses and in several cases in cosmonaut blood. Your statement regarding US vs Soviet approach to the space race is simply wrong.
Challenger? What's your point? That Russia didn't beat the US into space? I thought the west at least accepted that fact. Or do you just have to believe the US is ALWAYS "superior"?
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> As of 2020, there have been 15 astronaut and 4 cosmonaut fatalities during spaceflight. Astronauts have also died while training for space missions, such as the Apollo 1 launch pad fire which killed an entire crew of three The numbers don't really seem to support your assertion that NASA is generally much safer than Soviet/Russia
But the U.S. has sent 3x as many citizens into space: https://en.wikipedia.org/wiki/List_of_space_travelers_by_nat... So combining with your statistic the U.S. has a fatality rate of 4.4% versus Russia's 3.3%. Given the low N it's probably within margin of error.
Soyuz has launched 394 people and killed 4 of them. The most recent fatality was 50 years ago. The Shuttle launched 833 people and killed 14 of them, most recently in 2003 (8 years before the program ended). That gives Soyuz a fatality rate of 1.0% and the Shuttle a fatality rate of 1.7%. In other words: You're 70% more likely to die if you ride the Shuttle instead of Soyuz.
The more you look into the specifics, the safer Soyuz seems. The Soyuz deaths were early in the program while the Shuttle deaths happened when the program was mature. (Soyuz 11 was the last fatality and it was the 10th manned mission. STS-51-L was the 25th Shuttle mission and was considered to be safe enough for a civilian teacher to ride along. Oops.)
Soyuz's design is inherently safer. It has a launch escape system (which saved the crew of Soyuz 7K-ST No.16L).[1] The Shuttle did not. Soyuz's heat shield is much more robust than the Shuttle's. Soyuz's crew section is on top of the rocket, reducing the chance that any falling debris (or shrapnel caused by an explosion) will harm the crew module. Lastly, Soyuz uses liquid fueled rockets that can be shut off at any time. The Shuttle's solid boosters could not be throttled or shut off. All of these design decisions make for a simpler and safer vehicle. If I had to pick one, I'd ride Soyuz for sure.
Can they relight sooner to improve their odds of landing successfully, or is the window for when they can relight relatively small? Or does it not matter because a few more seconds won't increase the chances they'll be able to relight?
If you want to start burning a few seconds early on landing by policy, you need to lift that fuel, and the fuel to lift that fuel, from the surface to space and then decelerate all of that. Just for those seconds. If you’re doing this from Mars, you also have to accelerate that mass around the Solar System and out of the Martian gravity well.
Not a bad thought. Just wanted to illustrate how energetically leveraged these systems are.
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On the 'repeated failures' piece, that's somewhat new for aerospace. Traditionally, things would be over-engineered, and losing a test vessel would be considered a bad thing. SpaceX seems very content to blow up a bunch of rockets on their way towards not blowing up rockets. This seems to have caused at least part of their recent issues with the FAA, who seem to be less ok with explosions. It will be very interesting…
Plenty of American rockets failed, especially early on! https://www.youtube.com/watch?v=13qeX98tAS8
That's not quite the same situation SpaceX is in right now.
Of course, they'll have to land some other way on Mars or the Moon.
For both SN8 and SN9 my brain is screaming at me "surely they need more than 3 engines?!" Is the ultimate expectation that the engines will never fail, because it sure seems like they can't deal with losing even a single engine. I'm sure this is completely incorrect given that the issue for SN8 was tank pressure.
The issue is that the Raptor engines can only throttle down to 40% which represents a large thrust-to-weight ratio when you have basically just an empty tank. There is also a startup time for each engine, so if one fails Starship will likely hit the ground before they can light another. There are enough engines that a failure on ascent can be handled gracefully but landing is another story.
With respect to failure on ascent, I imagine in that case they just send up another starship and transfer in orbit (coming down has always been the hard part).
For both SN8 and SN9 my brain is screaming at me "surely they need more than 3 engines?!" Is the ultimate expectation that the engines will never fail, because it sure seems like they can't deal with losing even a single engine. I'm sure this is completely incorrect given that the issue for SN8 was tank pressure.
The issue is that the Raptor engines can only throttle down to 40% which represents a large thrust-to-weight ratio when you have basically just an empty tank. There is also a startup time for each engine, so if one fails Starship will likely hit the ground before they can light another. There are enough engines that a failure on ascent can be handled gracefully but landing is another story.
For both SN8 and SN9 my brain is screaming at me "surely they need more than 3 engines?!" Is the ultimate expectation that the engines will never fail, because it sure seems like they can't deal with losing even a single engine. I'm sure this is completely incorrect given that the issue for SN8 was tank pressure.
It'll be interesting to see what exactly happened with SN9, there's some clear video footage of piece flying off the rocket right as it was doing the flip maneuver.