RCgothic

Hurricane strength potentially on Wednesday, although may be within what the vehicle can tolerate. Could cause launch criteria violations all that week for the opportunities on 14th/16th/19th though.

The 30t of propellant is needed for landing. Putting it in the nose for stability is a two birds one stone situation. Getting rid of the landing propellant results in a crater regardless of the aerodynamic stability. Two-axis hinges are heavy, mechanically complex, difficult to defend against plasma penetration, and unnecessary because single-axis is sufficient.

Reports are the stage broke into 2 early in the re-entry and that's why it came down quite far short of the predicted centre.

Ouch: ಠ⁠_⁠ಠ

A steady state faster spinning earth wouldn't be too different. Apparent gravity at the equator would be lower, earth would be more oblate, and coriolis effects on wind and weather would be higher, and the natural cycles of lifeforms would be different. Possibly magnetic field would be stronger. An *accelerating* earth however would likely come with a lot of very not-fun mantle effects that could range from increased volcanic activity through total destruction of the crust.

Due to inclination the densest portion of the ground tracks is over the US and North Atlantic, and the southern Indian Ocean.

You can't hide your surface assets from satellites if there are *always* satellites overhead.

The meme is finally dead.

I like how they biassed Artemis II left but centred starship as though to imply Artemis II has any chance of launching early 2024.

The bottom line is that the only rocket that could send the enormously overweight Orion/ESM plus a lander with more than a few hours of endurance through TLI in a single launch is an expendable Superheavy. But there's also absolutely zero reason to strive for a single launch. Any system using distributed launch is much more capable, and the main flaw with SLS/Orion is that it's not distributed enough.

Artemis IV is the not a moon landing launch, isn't it? Somebody needs to take SLS/Orion out of this programme and shoot it.

Oh yes, those are typical DV requirements during transfer windows. Should have made clear. If anything they're slightly conservative, giving a little margin. Gives a little leeway over when to launch and inefficient manoeuvres en-route. For return trajectories you can hit pretty much any periapsis off the "intercept* figure.

This is how much DV it generally takes to go places in the solar system.

To add on to what @sevenperforcesaid, straight up is also a less efficient thrust direction. A rocket that could accelerate at 1.5G straight up could accelerate at ~2.3G horizontally whilst maintaining the vertical thrust necessary to counter gravity. This is the main reduction in gravity drag - getting pitched over as soon as possible increases acceleration, which decreases time under thrust. The shorter the time fighting gravity, the less energy is wasted. Reduction in apparent gravity due to centripetal acceleration also allows smaller, less massive engines to be used on the upper stage. Reduction in dry mass has an exponential effect on the final achievable speed. Burning straight up is the single most expensive way to get out of a gravity well.

It needs to be a URL link. Either select "open image in new tab" and then copy the URL from the address bar, or download the image and reupload it to an image hosting site like IMGBB, which will give you a link as part of the process. Then click insert image from URL in the bottom right of the forum reply editor. Alternatively tweets insert automatically when a link to the tweet is pasted into the editor. Sometimes just needs a few spaces adding after the end of the URL.

Landing and deployment confirmed.

The follow up HERA mission to inspect Didymos/ Dimorphos after the DART impact is being moved to SpaceX F9.

Interesting. The extension actually covers fewer vehicles than expected.

This is a joke. Of course no one else can make SLS rockets. What they should be asking for is vehicles that can perform the mission.

Not all of the work that's been done since the spring has been absolutely necessary. If the mitigated FONSI had been ready earlier I'm sure SpaceX would have MacGyvered a launch opportunity for B4/S20. The launch license is actually a fairly minor thing in comparison to the environmental assessment. It'll come through when SpaceX are ready to declare the launch vehicle is tested to a state of launch readiness.

The main benefits of a plane layout for a spacecraft compared to anything else are: 1) Larger area per unit mass and higher L/D means peak loading on the heat shield is reduced, allowing for non-ablative solutions (easier reuse). This also aids larger downmass. 2) Non-propulsive landing. Substantially safer than relying on engines 3) Use of existing landing infrastructure (airports). Land almost anywhere if necessary. 4) Landing on wheels is a relatively clean landing method. Theoretically it shouldn't take much to turn around a landed space plane. So if you want to bring a lot of mass back to earth, don't care too much about where you land, and want the vehicle to be rapidly reusable, a spaceplane is a fair design bet. The Space Shuttle never really brought down anything particularly heavy, in practice only ever landed at three facilities, and other design decisions compromised points 2 and 4. If you don't mind landing propulsively at the launch site, wings are pretty superfluous.