Silavite

That's very true, but Musk simply has to convince enough investors that profit is just over the next hill. I'd imagine that his image, popularity, and borderline cult-of-personality help with that. In the spirit of the old Keynes quote, "The market can stay irrational longer than you can stay solvent."

I think that it's also instructive here to consider that in terms of motivation, Musk isn't a normal CEO. Musk's goal with SpaceX is to make humanity interplanetary; large-scale reuse (even if it hypothetically isn't the most economical option right now) and orbital assembly/refueling are almost certainly going to be part of that. If SpaceX is making a huge profit, that's great, but I don't think that Musk really cares about profit in the grand scheme of things. As long as he can control the company and keep the investors from retreating, that's good enough for him. To risk going off topic, I'd wager that line of thinking is part of the reason why Tesla is eating up so much money as well. Whether Tesla is profitable doesn't greatly concern Musk. He just wants to grow the EV industry in general as quickly as possible by maximizing production and minimizing price. (Disclaimer: I'm not the most well-read on Tesla, so I apologize if this comparison is totally off-base.) I'd even go so far as to say Musk is an activist first, and a CEO second, but perhaps that's going too far. (Also, just to put my own stake in this, I do think that reuse helps SpaceX's bottom-line, but I can't say for certain.)

Interview with Beck by Ars Technica I will say that I found this statement interesting⁠— This statement seems to suggest that there could be enough demand for a similarly sized LV for another company to be successful—even after the inevitable industry shakedown. And on the subject of a shakedown... I couldn't have imagined having 130 small-launch vehicle companies existing a decade ago. It's amazing how times change.

If Starship alone is short of dV to orbit, it may still be able to fly a mission similar to the Shuttle's abort once around profile.

Regarding Bridenstine's 2021 comment, I'd like to add Jeff Foust's interpretation as well. Here's Eric Berger again for reference (just the article's headline). Jeff and Eric have a similar read on this, so I'm inclined to believe that Bridenstine is ruling out a 2020 launch.

As long as they aren't gyroscopes hammered in upside down.

In these days where simulation is supplementing physical testing in aerospace, there is something gratifying about watching SpaceX's experiments.

Encouraging that this is Gwynne time and not Elon time.

This is welcome news. https://spacenews.com/nasa-seeks-a-rapid-launch-of-a-lunar-lander/

I just saw a pass at 21:45 CDT from Houston. All I can say is that the real thing lives up to (and surpasses, in my opinion) the videos and pictures! That said, I did have the benefit of a clear sky and the peak elevation was 80 degrees, so your mileage may vary.

Obligatory: That said, I do think the chances are better than 1 in 1,000,000. If funding materializes and there aren't any major snags with the hardware, then it is certainly possible.

Though I think it not likely, there is indeed a non-trivial probability that SpaceX could fail. The argument of market uncertainties becomes less effective when one considers that SpaceX is not the only company developing heavy launch vehicles. Bezos has effectively unlimited capital for Blue Origin and New Glenn. ULA's proven record and government connections will help it to push Vulcan along. The concern that SpaceX could fail is perfectly reasonable; however, the concern that SpaceX, Blue Origin, and ULA could all fail seems a bit far-fetched. [EDIT] Well, looks like I was just a bit too slow...

Seconded for the original STS architecture. I find the reusable agena to be particularly fascinating.

To think that this is an April fools prank and yet this is not. The mind boggles.

Thanks for the answers! I've read Ignition before, but it's been a few years. After reading your post, I now remember the bit about the corrosion problems with RFNA and the discovery of IRFNA via the addition of small amounts of HF, but I had totally forgotten about the freezing point concerns in tactical missiles. Perhaps this shows that I should give it another read in the near future...

After some study of the history of rockets (and playing some RP0), I noticed that the most common storable oxidizer in the late 1950s through the early to mid 1960s seemed to be nitric acid. However, by the late 1960s and beyond, nitric acid had been supplanted in most applications by N2O4. Why did this switch occur? Was it motivated by ISP, corrosiveness, handling characteristics, density, boiling/freezing point, or something else entirely?

In aircraft, g loads are directed from head to foot. With astronauts seated in couches, they are directed from chest to back. The human body has a much greater tolerance for the latter.

I think that a certain commenter on this article put it most succinctly.

(Paging @ProtoJeb21) I'm working on a very simple model for the atmosphere of an exoplanet, and I'm a bit stuck. I understand that it is possible to find scale height and the composition of an exoplanet's atmosphere. It should be possible to roughly find the planet's average temperature from the parent star's irradiance at the distance of the exoplanet. Is it possible to get an absolute value for density or pressure at an altitude from direct observation and thus create a rudimentary atmospheric model? (Assuming a very simplistic single layer atmosphere).

Oops?

More on topic; how quickly can SpaceX start producing Raptors en-mass? Although the hopper only needs 3, each Superheavy and Starship combo will need 38(?) Raptors in total.

I really hope that they don't spend months getting all the infrastructure in place... and then a hurricane hits in September. I'm way too pessimistic sometimes.

Well, this is certainly convenient from my perspective.

In the classes I've taken, I feel like this isn't much of an issue. For example, in my calculus 3 class this semester, we were not allowed to have calculators on tests, but our tests would have some problems which would say, "set up, but do not evaluate." Generally this meant to apply whatever methods we learned, and stop once we had the problem in a form which could be solved by methods from calculus 1 or 2 (usually a definite integral; maybe a double integral on some problems with Stokes' Theorem). Some problems would be in this form, and some would require an exact numerical answer. This allowed tests to touch on our computational knowledge while keeping the majority of the assessment on material learned in class. In summation, a good instructor will write assignments that account for whether a calculator is allowed.