Cubecab doesn't have a dedicated thread here, and it appears for a good reason.TRMO interview with Adrian Tymes, the CEOhttps://www.youtube.com/watch?v=ULBbpAYARI8?t=1678I'm halfway through and absolutely nothing about this sounds even remotely credible
Quote from: savuporo on 07/23/2017 09:58 pmCubecab doesn't have a dedicated thread here, and it appears for a good reason.TRMO interview with Adrian Tymes, the CEOhttps://www.youtube.com/watch?v=ULBbpAYARI8?t=1678I'm halfway through and absolutely nothing about this sounds even remotely credibleWell I think his estimate about stuff having an orbital lifetime of 25 years at 400Km is low, given the estimate for Propero (at 500Km) is more like a century. They also seem to be planning to use an F104 Starfighter for the first stage. I'm surprised any of them is still in flying order, although obviously if they can get to closer to M2 than M1 that would be a significant improvement on the size of the nozzle. Of course that's a pretty high lb/$ figure.
Quote from: john smith 19 on 08/15/2017 09:24 pmQuote from: savuporo on 07/23/2017 09:58 pmCubecab doesn't have a dedicated thread here, and it appears for a good reason.TRMO interview with Adrian Tymes, the CEOhttps://www.youtube.com/watch?v=ULBbpAYARI8?t=1678I'm halfway through and absolutely nothing about this sounds even remotely credibleWell I think his estimate about stuff having an orbital lifetime of 25 years at 400Km is low, given the estimate for Propero (at 500Km) is more like a century. They also seem to be planning to use an F104 Starfighter for the first stage. I'm surprised any of them is still in flying order, although obviously if they can get to closer to M2 than M1 that would be a significant improvement on the size of the nozzle. Of course that's a pretty high lb/$ figure. Not an expert on this, but the 25 years at 400km vs ca. 100 years at 500km seems entirely believable to me. Keep in mind that orbital decay is basically an exponential thing - the lower your orbit is, the more atmosphere to slow you down and the more atmosphere there is, the faster you will be losing orbital altitude.
They also seem to be planning to use an F104 Starfighter for the first stage. I'm surprised any of them is still in flying order, although obviously if they can get to closer to M2 than M1 that would be a significant improvement on the size of the nozzle. Of course that's a pretty high lb/$ figure.
Interstellar Technologies -- a Japanese rocket venture established by entrepreneur Takafumi Horie -- recently failed in the launch of its Momo rocket, but vows to carry on with its space program. Based in Japan's northern island of Hokkaido, the company hopes to launch a rocket capable of carrying ultra-small satellites in 2020.
Ripple:Wait a second.They are going to tow a rocket full of liquid hydrogen and liquid oxygen through the water?What could possibly go wrong?Then the rocket, with the payload on the end, just tilts to vertical.And the choices are ignite the engine inside the "ballast cap" or under water.Really?
Well, so I was at the Review of Australia's Space Industry Capability Adelaide Roundtable Meeting this morning and someone says they are from a company called Ripple Aerospace looking to launch satellites from South Australia. I was next to a guy from Southern Launch with the guy from Ripple next to him. I later went up to him to ask him a few questions about what they are doing. He's an Australian working for Ripple, which is based in Norway. They are looking to launch a sounding rocket called Agar 1 by the end of the year, with South Australia being considered as a possible launch site, as we have lots of empty ocean to the south. Their launch vehicle is called Sea Serpent, a LOX/LH2 two stage vehicle using aerospike engines. Payload is 2.6 t to LEO.https://rippleaerospace.com/
Quote from: Comga on 09/06/2017 06:47 amRipple:Wait a second.They are going to tow a rocket full of liquid hydrogen and liquid oxygen through the water?What could possibly go wrong?Then the rocket, with the payload on the end, just tilts to vertical.And the choices are ignite the engine inside the "ballast cap" or under water.Really?Bigger problem I see is the values listed for maxQ, might be just a typo, but there is no way that speed is right.
9.2 kps LEO speed also seems unusual.
Well, so I was at the Review of Australia's Space Industry Capability Adelaide Roundtable Meeting this morning and someone says they are from a company called Ripple Aerospace looking to launch satellites from South Australia. I was next to a guy from Southern Launch with the guy from Ripple next to him. I later went up to him to ask him a few questions about what they are doing. He's an Australian working for Ripple, which is based in Norway. They are looking to launch a sounding rocket called Agar 1 by the end of the year, with South Australia being considered as a possible launch site, as we have lots of empty ocean to the south. Their launch vehicle is called Sea Serpent, a LOX/LH2 two stage vehicle using aerospike engines. Payload is 2.6 t to LEO.
Quote from: groundbound on 09/06/2017 06:11 pm9.2 kps LEO speed also seems unusual.That's actually explainable. 9200 m/s is a rule of thumb orbital speed for LO2/LH2 rockets including all losses, which are usually expected to be a bit higher with LO2/LH2, in the same way old rocket engineering books list 30kfps (9144m/s) as the round number to achieve orbit. What's rare is quoting it as it's a placeholder. Smart rocket developers optimize their trajectories to reduce losses because every m/s you can reduce them by means you can either deliver the payload with a smaller rocket or a bigger payload.
Quote from: Comga on 09/06/2017 06:47 amRipple:Wait a second.They are going to tow a rocket full of liquid hydrogen and liquid oxygen through the water?What could possibly go wrong?Then the rocket, with the payload on the end, just tilts to vertical.And the choices are ignite the engine inside the "ballast cap" or under water.Really?Underwater ignition has been demonstrated plenty of times. See Seabee and Sea Horse. I suspect the fuelling would be at sea, this was the plan for Sea Dragon. Like you say, towing it fuelled will lead to big time ice formation, unless the insulation is massive. Not that hydrolox fuelling at sea would be a walk in the park.
Quote from: john smith 19 on 09/07/2017 08:53 amQuote from: groundbound on 09/06/2017 06:11 pm9.2 kps LEO speed also seems unusual.That's actually explainable. 9200 m/s is a rule of thumb orbital speed for LO2/LH2 rockets including all losses, which are usually expected to be a bit higher with LO2/LH2, in the same way old rocket engineering books list 30kfps (9144m/s) as the round number to achieve orbit. What's rare is quoting it as it's a placeholder. Smart rocket developers optimize their trajectories to reduce losses because every m/s you can reduce them by means you can either deliver the payload with a smaller rocket or a bigger payload.If they are running with a mini Sea Dragon, then they would be epitomizing the Big Dumb Booster concept, which implies they may care less about the trajectory optimization if it makes manufacturing cheaper. Fuel is cheap, brute forcing it is in theory easier, much more so if you are doing a floating launch as there are almost no launchpad/TEL considerations.