sevenperforce

The webcast is showing live at 1:12 PM Eastern.

But it's not, because it's TINY.

Popescu looks like he just found out his girlfriend has been cheating on him with Arnold Schwarzenegger. The shot of the aerospike on the test stand is Photoshop. The "Helen Engine" test from freaking 2009 is their HTP monoprop test. Really nothing to do with this. I mean, yes, they're using HTP+kerosene, which is a time-honored bipropellant combo (I still love the hell out of Black Arrow) but the aerospike is a different beast. Is it possible to use HTP decomposition for self-pressurization? I think it ought to be possible. Haven't figured out a way to make it work yet, though. No, that was Firefly. They ditched their toroidal single-chamber aerospike. ARCA has always had a linear aerospike. Which, FWIW, is probably the way to go. A multichamber linear aerospike gives you pitch, yaw, and roll using nothing but differential thrust, and you can do it pressure-fed. I've said it before and I'll say it again -- the smallest possible reusable launch vehicle is a parallel-staged linear aerospike packing self-pressurizing keroxide, with chuted recovery. It's the only prop combo that can beat out solids in impulse density while still maintaining enough Isp to put something useful into LEO-300 m/s.

Good to see the black interstage and black legs on the patch! By my numbers, Falcon 9 Block 5 could barely pull off a 3500-kg launch to GTO and still RTLS, but it would take an 0-1-3-0 true suicide burn at LZ-1, so it's no surprise they're opting for ASDS. Too bad Mr Steven is still in LAX. Do they have an east coast fairing-mitt ship?

......but have they done anything?

And like the universe, you expand fastest when you are youngest. Almost...inflationary.

Seriously? How..what...cite?

Evidently there was some uncertainty as to whether there would be four or five F-1 engines on the first stage; we almost ended up with the Saturn IV. Had they chosen to use RL-10 engines rather than J-2s, they would have needed no fewer than 13 of them on S-II.

The man himself disagrees:

The needle moving left rather than right is what shocks me.

The redshift of a gravitational wave would be shown as an increase in the length of the measured duration of the gravitational merger event. The last LIGO detection event lasted 0.15 seconds, I believe. The merger itself took much longer, of course; that 0.15 seconds was only the length of time during which the amplitude of the spacetime fluctuation exceeded LIGO's detection limits. But that portion of the merger was originally lower. Redshift at the edge of the universe is a wavelength multiplication factor of around 3.4; if LIGO detected this black hole collision at the edge of the universe, then the true duration (of this portion of the spacetime fluctuation) was probably something like 0.04 seconds and it has simply been stretched out. But the galaxy with the black hole merger was 1 billion lightyears away. That's far, but it's not very far in cosmological terms; only about 2% of the way to the edge of the observable universe. And expansion is metric. So the actual duration of this part of the fluctuation was probably just 0.14999999999995 seconds or so. Come to think of it, that's a theoretical (if experimentally impossible) verification of Hubble's Law. Since the masses of the black holes can be known independently, their merger could be modeled, and the duration of the merger peak could be predicted. Deviations in the duration of the merger peak would be a direct measure of redshift.

Must have been glorious.

HOLY MOTHER OF

What I'm trying is launching retrograde and letting the rotation bring me back in range.

Ah, I see what you're asking. The answer is no. Redshift of gravitational waves does not change the parameters of the gravitational field tensor. You just have to solve the tensor equations for an expanding reference frame. Also, redshift of gravity waves doesn't mean the gravity waves are weaker. Gravitational force is proportional to gravitational potential, represented by the amplitude of the gravitational wave. Redshift is a change in the frequency of a wave. Redshift lowers the frequency (and the corresponding flux energy) of photons coming from distant galaxies. In that sense, redshifted light is "weaker". But this is to be expected; the photon has been stretched across a greater amount of space, and so that energy is spread out. If a star emitted a photon when it was 1 billion lightyears from us, and that star is now 2 billion lightyears from us, then the photon has been stretched out to twice its original wavelength or half its original frequency.

Yes, gravity waves are redshifted. But gravity waves are so weak when they reach us that minute frequency changes would be undetectable. The key feature of the expanding universe is something called metric expansion. In other words, space itself is expanding, and everything is moving away from everything else, rather than everything moving away from some single point. How do we know this? Well, suppose that the reverse was true, and everything was simply moving away from one specific region. If this was the case, then we would see redshift in most directions, but galaxies with the same vector as us (in other words, galaxies "behind" or "in front" of us, relative to the region everything is moving away from) wouldn't be redshifted at all. Or, depending on how the expansion was happening, some would be redshifted and some would be blueshifted. Instead, we see redshift in all directions, and the farther away something is, the more redshifted it is. The only way this is possible is if everyone everywhere in the universe is seeing the same thing as everything is moving away from everything else. We are fortunate to live in a (cosmologically) brief period of time during which we can still see the afterglow of the big bang. Before the big bang, the whole universe was in a hot, dense state, and then inflation started. After inflation, the universe was not nearly quite so hot or dense...but was still about as hot and dense as the core of the sun, which is pretty hot and pretty dense. The universe continued to expand in the post-inflationary epoch, for about three hundred centuries. At this point, it had expanded and cooled to the approximate density and temperature of the surface of the sun. At this point, however, light still didn't exist as we know it. The whole universe was full of plasma, and with nowhere to go, photons simply didn't propagate between atoms. It was all one big dark hydrogen ocean. Then, at three hundred centuries of age, the expansion broke the light and the darkness apart, and photons decoupled from hydrogen atoms and scattered out into the new universe. The whole universe changed from dark to light in a single moment. Nearly 14,000,000,000 years later, we can still see those photons from last cosmic scattering. We sent up satellites to take a picture of it all. Here's what it looks like: So there you have it.

Does anyone know whether the New Glenn has aft RCS?

What he said. That was Von Braun's idea, btw. The next planet out from Jupiter is Saturn, so the next-biggest rocket family after Jupiter was named Saturn. The tank-clustering thing was only because they had tanks sitting on the shelf. They clustered Redstone tanks around a Jupiter tank; it wasn't one or the other. That was quicker than tooling a brand new 6.6-meter tank. They put thrust plates above and below the cluster of tanks. The H-1 engines were technically derived from the S-3Ds used for Jupiter, but they had gone through a complete redesign already to become the X-1 and then they were further updated and altered to the point of no longer being recognizable by the time they were clustered under the Saturn 1 thrust plate.

On the plus side, once we have warp drive, we can use it to get to block 2! because it's so far away that wasn't very funny

Maybe a little.

During the first flight, the booster stage crashed and was not recovered due to a failure of hydraulic pressure in the vehicle control system during the descent.

They can.

I made that graphic; wasn't anything official from ULA.

Yeah, they open the fairing hatch and the Soyuz capsule hatch on the pad, when the rocket is full of propellant. Support staff are in and out of the hatch at this time, securing them. Any catastrophic problem during this phase would be LOC because there's no way to get away from the booster. Good catch. Well, presumably there's never going to be an abort in a LOC event. That's not really entirely true. They did have provisions for certain types of abort, namely those that would leave the orbiter intact but unable to achieve orbit. In that case they had various emergency landing strips scattered about the path that the orbiter might be following. Hence why I said "catastrophic" abort. Any structural failure or even a thrust imbalance between the SRBs was LOCV. No catastrophic abort provision. IIRC, the parallel sensor on another engine was also faulty and was getting ready to shut it down as well. If that engine had shut down, the orbiter wouldn't have had enough thrust to survive through SRB jettison.

The very first Shuttle flight, on Columbia, had ejection seats for the two-man crew. The utility of these seats was in dispute; an ejection while the solid boosters were still firing would almost certainly have left the astronauts inside the SRB engine plume or too close for comfort. Ejection after the solids were jettisoned was likely too high for survival. There was no provision for pad abort. Flights after STS-1 had no provision for catastrophic abort whatsoever. The ejection seats were removed because there weren't enough seats close to windows for everyone to have an ejection option.