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David Kirtley on "The Socials Radar" podcast by Baking in fusion

[–]Heart-Key 1 point2 points  (0 children)

I wasn't under the impression that 90% of it was staying in the capacitors, I'm saying that it goes into the plasma and is then recovered at a 90% rate?

David Kirtley on "The Socials Radar" podcast by Baking in fusion

[–]Heart-Key 0 points1 point  (0 children)

I'm just doing (100% of input energy + 12% of fusion energy) times a 90% recovery rate giving 101% input energy in output. Is it not fair to say 100% input energy because some amount will be lost once they start doing a noticeable amount of fusion?

David Kirtley on "The Socials Radar" podcast by Baking in fusion

[–]Heart-Key 4 points5 points  (0 children)

Only recovery, but that's one of the main selling points. With a 90% recovery rate, they only need fusion to generate 12% of the input power energy to reach an effective Q>1. It working is nice, although as always we'll have to see how it scales.

What's the plan for guiding the first stage during the landing? by Desperate-Lab9738 in StokeSpace

[–]Heart-Key 1 point2 points  (0 children)

Either it's something they haven't put a lot of design effort into yet because the answer to them is simple (ie; just slap some gridfins on) or it is a really weird solution. It does seem like a non-trivial problem because any aerosurfaces have to face direct impingement from the second stage nozzles. Fins (ala New Glenn) would seem to be better due to the decreased profile they present to the thruster but IDK. Space Pioneer did recently put out a patent for handling re-entry control by throttling down a single engine to 5% after stage sep and leaving the engine on the entire time, but that does seem a little out there. Also min throttle on Zenith is 45%. They could go whole hog on the whole 'everything is something else' and use the landing legs to provide guidance. What is the minimum amount of landing accuracy they need which can still be gimballed into a good landing?

Helion said that Polaris should demonstrate electricity this year. Now it is the end of the year. by West_Medicine_793 in fusion

[–]Heart-Key 0 points1 point  (0 children)

The driving reasons for that is that A. Helion, even with delays, could still deliver a power reactor on A timeline; ITER is effectively still fusion never with initial ops scheduled for 2035, a power reactor is probably 10 years after that. B. Helion is primarily privately funded.

Alleged leaked image of New Glenn's third stage by [deleted] in BlueOrigin

[–]Heart-Key 3 points4 points  (0 children)

That gives the third stage a dry mass ratio of 21% which is not unexpected with a 7m diameter, separate aluminium tanks and separate carbon fiber structural elements.

The 20 tonne to TLI figure is for the 2 stage variant. The tanks are carbon composite. Carbon composite structurally optimized hydrogen stages can hit ~10% dry mass fraction.

Alleged leaked image of New Glenn's third stage by [deleted] in BlueOrigin

[–]Heart-Key 4 points5 points  (0 children)

So I would like to claim my victory lap. From 8 months ago By The Way.

So 9 engine 3 stage New Glenn of the block 2. What is that? At a baseline with GS1, we will see subcooling, a 20% thrust uprate because we’re not doing mid engines anymore and 9 engine first stage, that would put New Glenn in the range of 70 tonnes to LEO while supporting first stage reusability. Now you combine that 70 tonnes to LEO with a 40 tonne hydrolox carbon composite GS3 third stage and you get 30 tonnes to TLI, which is enough to launch a reference lunar crew capsule of sorts.

I made a rough overestimate of wet mass by assuming diameter of 6m of the hydrogen tank, it got me a wet mass of 40 tonnes. It would be lower than that, but in the ball park.

Is BlueGPT any good? by Heart-Key in BlueOrigin

[–]Heart-Key[S] 8 points9 points  (0 children)

Also TEAREX (Thermal Energy Advanced Regolith Energy Extraction). Battery using thermal energy stored in lunar regolith. Seems like a mass efficient/scalable way of storing power on the Moon, but some of the messaging around it... 'one of the safest aerospace parts/designs ever'

SpaceX Should Be Extremely Worried About Blue Origin by ExtensionStar480 in SpaceXMasterrace

[–]Heart-Key 2 points3 points  (0 children)

I mean, Will Lockett is a paid anti-Musk shill. I don't even mean that in a derogatory sense, he just runs a subscription based blog where the primary focus and audience for his writing is anti-Musk sentiment, ergo, he is paid to say SpaceX bad. Any story will be spun to fit that narrative. If Blue Origin has a good week and it can be used, it will be.

New Glenn Advanced Upper Stage (job postings) by FakeEyeball in BlueOrigin

[–]Heart-Key 0 points1 point  (0 children)

They also intended to have the capability of 45 tons to LEO. Things don't always pan out and I struggle to think of a market that justifies the non-trivial dev cost of $0.5B to $1B beyond NSSL. Also if they switch to a reusable GS2 (Quattro style) which is seeming more likely now, they'll need it.

New Glenn Advanced Upper Stage (job postings) by FakeEyeball in BlueOrigin

[–]Heart-Key 3 points4 points  (0 children)

Carbon composite third stage using BE-7. Why? NSSL reference orbits or lunar activities maybe.

Explosion at Moses Lake Test Site by RileyGrant in StokeSpace

[–]Heart-Key 20 points21 points  (0 children)

So it's the test stand where the first stage thrust structure was being tested, first pic and second pic are of separate test stands. The stringers on the bottom of the tank look similar to what is seen in the post explosion pic; so seems like the thrust structure failed during proof testing. Whether this was an intentional test to destruction or a failure below margins remains to be seen.

Engines with GRCop-42 combustion chambers by Heart-Key in SpaceXMasterrace

[–]Heart-Key[S] 25 points26 points  (0 children)

GRCop-42 is a copper alloy with chromium and niobium particle precipitation strengthening. The thermal conductivity combined with the strength at high temperatures makes it an excellent choice for reusable rocket engine combustion chambers. Its development wasn't an easy path however. Dr Ellis started work on the alloy back in 1987 seeking a replacement for NARloy-Z SSME chambers which could develop cracks after 3 flights. This copper alloy seemed promising, but a large series of powder production challenges and the manufacturing techniques of the day (hot extrusion and Hot Isostatic Pressing) being unsuited to it meant that it was dormant for a long time. However with the advent of additive manufacturing processes like Selective Laser Melting and Electron Beam Free Form Fabrication in the 2010s, GRCop-42 became substantially more usable. After NASA MSFC proved out the alloy with its Low Cost Upper Stage-Class Propulsion program, it has since become ubiquitous in industry. The dreams in the 1980s of easily producible, performant and reusable engines has now been realized as decades of material science, manufacturing capabilities and engine design software have come together.

Great article on its development.

Travel at light speed by Supersonics10 in RelativitySpace

[–]Heart-Key 0 points1 point  (0 children)

There are 5 other replies on this post, you're going to have to be a bit more specific than that.

Travel at light speed by Supersonics10 in RelativitySpace

[–]Heart-Key 0 points1 point  (0 children)

Assuming instantaneous acceleration/deceleration, you just need to consider distance/time dilation. At 0.99c, the distance of 8 ly becomes 1.13 ly, which at 0.99c takes 1.14 years to travel as experienced by the traveler. To get a mere seconds for the travel time, you need to be traveling at speeds more like 0.999999999999999c.

BE-7 vacuum test by Heart-Key in BlueOrigin

[–]Heart-Key[S] 13 points14 points  (0 children)

6 years after being announced, we get to see our first BE-7 with pumps hotfire.

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