Starman4308

This suggestion would add needless complexity and only really affect super-long-duration missions like maximum-efficiency Grand Tour missions and communication relays. There is already a strong balancing element in that they are expensive and very heavy compared to their EC output. While not totally realistic, many of these long-term efforts produce some of the most spectacular KSP missions.

Except possibly for some specialized manufacturing techniques (for which modern, often superior alternatives exist), we still have the technology. What is lacking: The skilled engineers and technicians who built the originals. All the little process details that never made it into the blueprints: things like "this bit usually needs to be filed down a bit" that never made it into the permanent documentation. Many of the necessary supply chains. IBM isn't exactly in the business of making S-IVB instrument rings anymore. We could almost certainly build a new rocket that outwardly resembles the Saturn V, and probably outperform it slightly to boot. On the inside, though, it'd be a whole new design: modern avionics, modern manufacturing processes, etc... and it's the fine details that make rocket design expensive, not aping the outwards dimensions.

That won't work for geosynchronous orbits. Spacing by a fraction of Kerbin's sidereal day works well for spacing longitude of the ascending node, but that's arbitrary for geostationary birds. What does work is to initially place them into a resonant orbit, and circularize after different numbers of orbits. For example, if you did a 2/3 resonant parking orbit, one would circularize after two orbits, one after one, and one immediately on hitting apoapsis.

Only the precession bit is necessary. Riding the day-night terminator is optional for sun-synchronous orbits; you can have one that, for example, stays at around 12:00 AM and PM. It's mostly about consistent lighting for imaging.

First: I'm mostly bashing Congress, Boeing, and other contractors. You know, the ones who are keeping this zombie horse alive whilst sucking enormous amounts of money from more useful projects. That doesn't make it better, nor does it excuse cost overruns on the LEM, part of a project that was mostly intended to stick it to the Soviets. Apollo is not a sacred cow. It just had the political will behind it to power through its problems. We're talking about the same cluster of organizations (NASA and its major contractors) who are one of only two organizations to ever build an SHLV, right? And the political influence continues to show itself, as political pressure ensures astronauts will be placed on the SLS with a vastly abbreviated testing campaign compared to the commercial crew vehicles. SLS is not being driven by safety; the current lunar landing plans are neither the safest nor the most efficient way to get to the Moon, it's just the only one that can go on the SLS. That an organization can be over-funded and suck needless taxpayer dollars from other programs doesn't excuse the fact that Congress is engaging in wasteful porkbarrel spending on a bridge-to-nowhere. Given the extensive history we have with Boeing and these other long-time contractors, it would have been very safe to say from the outset that the budget was a fantasy and that the contractors would suck every penny possible out of a cost-plus contract while providing the bare minimum product. Also, you're talking to somebody who habitually puts launch-abort systems on his KSP launch vehicles and runs unmanned tests of everything first, not to mention somebody who is extensively criticizing the idea of using the Superheavy/Starship to launch astronauts without an LES. So, please, don't make assumptions about me. The goals set for NASA are to funnel money to Shuttle-era contractors, not to do anything actually productive. While it was slightly less insane at its conception, where Delta IV Heavy was the only commercial US-built HLV, it's just about unjustifiable in today's climate. Semi-reusable commercial LVs are here to stay; even if SpaceX goes bankrupt, it's almost guaranteed that somebody will snap up the Falcon 9/Heavy. Multiple companies are working on further semi-reusables. Even expendable LVs are getting cheaper, with the power to launch significant blocks of any mission that requires assembly. I would concur that NASA is not wholly wasteful. The unmanned program (with the possible exception of JWST) has been very effective at expanding our knowledge of the universe. The key subsidies to SpaceX and other upcoming companies like Rocket Lab are driving new commercial growth. It's mostly SLS that I'm complaining about. I would disagree about SLS being unprofitable. It's very profitable... for Shuttle-era contractors. Not for the American people to which NASA is theoretically beholden. It's also very much not first-of-its-kind. That would be the Saturn V. Or the Shuttle. SLS isn't driving technology forwards. It's using primarily 1970s/1980s technology in ways best designed to funnel money to entrenched contractors. Additionally, it's not exactly hard to take a look at the state of the commercial launch industry, and design payloads that could fit on multiple LVs, including proven expendable (or, in one case, semi-reusable) LVs, in case any specific one fails. NASA brings a lot of good to the industry. SLS brings a lot of good to very specific, entrenched Shuttle-era contractors. There's nothing really novel about it: the engines are largely warmed-over Shuttle engines with a dose of RL-10 engines, and the structure and fuel tanks are, to my knowledge, pretty conventional. Any way you slice it, SLS is an expensive bridge to nowhere, liable to be cancelled the moment the US government gets into a budget-cutting mood and Shelby gets over-ruled. The few missions tasked to it are being designed around its capabilities, instead of SLS being the best solution to any given mission. Even with LOP-G, everything is being warped around what SLS can do instead of being the best way to get to the Moon. In the current economic climate, there is no justification for SLS. With the rapid advances in commercial LVs, what is called for is a wait-and-see approach. Continue to make probes, maybe build some modules for a space station that can go to LEO on extant commercial LVs. If we get a good crop of heavy LVs with costs an order of magnitude less than SLS with an order of magnitude better flight rate, then NASA can make much more ambitious plans that are an effective and efficient use of taxpayer dollars. If we don't... well, we still have a crop of probes to launch and an LEO station, and we can consider restarting the SHLV program with a clean-sheet design, made for a purpose instead of purposes being made for it.

Does oxygen absorb significantly into things like fabric? I'd imagine the local partial O2 pressure would drop tremendously in the seconds after ejection, going from 1 atm to local atmospheric conditions (potentially very low in upper atmosphere).

And, like many such failures, that boils down to "does the LES work?" LRBs aren't immune to blowing up their own tanks either, though those can be shut down early if the need arises. Either way, it's probably a mission-abort scenario where the LES probably needs to work. Nothing's perfect, but I'm pretty sure the SRBs of today aren't quite as terrible of an idea as the original Shuttle SRBs... and they're certainly being used in a safer context (i.e. there's an LES).

Because Thiokol's SRBs are the perfectly reliable wave of the future, don't you know? Also that it would've doomed the crew for most of the SRB duration, as RTLS was outright impossible until the Shuttle obtained enough energy to not just crash back down. It'd only be useful in the last segment of the SRB burn. It's not the safest thing in the world, but a lot of the risks involved in SRB use are strongly mitigated in the SLS and Atlas V/Starliner combination. Both have a functional launch abort system to get astronauts off the stack. Neither has the crew cabin too perilously close to the SRBs. Furthermore, for the Atlas V, the SRBs are relatively small compared to the booster core. This means that if there is some major problem, the liquid engines can shut down, and the core stack TWR will not be too high even with the SRBs burning, giving the Starliner more time to escape and separate from any wee little "fragments of still-burning SRB exhaust". This also gives a liquid-only TWR of almost 1.0 at launch, meaning sudden loss of SRB thrust does not immediately mean fall-back-to-the-ground except in the first seconds of flight. They're also well-proven designs, and I think they're monolithic, without the multi-segment joints of the SLS boosters. Remember: the Shuttle was thought to be a wonderful vehicle that would be the future of space travel. NASA thought it was invincible. Why not add in cross-range capability? We landed people on the freaking Moon! Then reality ensued. I'm not convinced the pure-oxygen cabin would be a huge threat in event of an ejection. Sure, they would've been followed out by a good old blast of oxygen... that would very quickly dissipate. Probably slightly less safe than the originally-tested 80% nitrogen atmosphere, but the dangers of a 1-atmosphere oxygen partial pressure are easy to overstate: the astronauts would be removing themselves from said environment with much haste. (also, it's a pet peeve of mine when people speak of the dangers of a pure oxygen environment. It's not the purity that's the issue: I'm pretty sure the ISS runs at 100% oxygen at 0.22 atm. It's having 1 full atmosphere partial pressure of oxygen that gets stuff extra-flammable).

You know, as much as I want the Shelby Launch System to just die already, another part of me still cringes every time it comes out that, once again, the SLS is over-budget, behind-schedule, with obvious design flaws. The sheer overwhelming waste of it all is mind-boggling, and the sheer cycnical self-interest involved... Naturally, Congress will blame everybody except the ones most responsible for this disaster: themselves.

Except for the first seconds of flight, any debris should just rain down on the Atlantic Ocean, and my suspicion is that they're going to try for an abort test at Max-Q, likely far enough downrange that everything just hits the ocean.

The issue with the notion of using this to deal with scrap aluminum is that, unless possibly you are dealing with very low-grade scrap aluminum, it's much better just to recycle the aluminum, which skips the expensive hassle of separating aluminum from the oxygen that loves it so very much.

The big factors here are Kerbin's rotation and that, when in a stable orbit, you always return to the place of your last maneuver. At the equator, Kerbin rotates by about 175 m/sec. As such, when launching due east from said equator, you gain 175 m/sec of bonus velocity. Launching due north, you don't actually get a 90 degree orbit; you get something like 85-ish degrees inclination. This is because, while you're adding northwards velocity... you're not cancelling out the eastwards spin of Kerbin. To actually get a perfectly polar orbit, you have to launch slightly west of north. Launching due west, not only do you lose the 175 m/sec spin advantage, you have to pay it all over again just to hit zero horizontal velocity. As such, it's a 350 m/sec penalty to launch west. At a higher-latitude site, you start with less velocity from Kerbin's spin, all the way down to zero were you to launch from the poles. This can help when launching to polar or retrograde orbits, as you have less eastwards velocity to cancel out... but it is a hindrance if you do want to go for an eastwards or mostly-eastwards orbit. One other significant advantage of equatorial launch sites is the ability to access low-inclination orbits without plane-change maneuvers. You always return to the last place you made a maneuver. So, if you make your ascent-to-orbit at 40 degrees latitude, even traveling due east, your resulting orbit will have at least one point at +/- 40 degrees latitude, meaning an inclination of at least 40 degrees. While there are multiple tricks to make this less of an issue, it'll still always be a fundamental limitation: no equatorial orbits without some sort of dog-leg or plane-change maneuver. This is part of why the real-world Korou is a fairly attractive launch site; being dead-on at the equator, Korou not only gets a substantial benefit from Earth's spin, but it also minimizes the plane-change to get to geostationary Earth orbit.

That's not going to work except for energy storage. You need to pump a huge amount of energy into alumina to refine it to metallic aluminum, more than you'll get back from the hydrogen.

I don't think SpaceX intends to try to recover the booster from this one. The intent is to simulate a first-stage failure, where the range-safety charges will be detonated to ensure the rocket is just so much rocket confetti.

How things are digitized in a modern CPU: High voltage = 1 Low voltage = 0 Transistors have a gate and a channel. Voltage can only go through the channel if the gate is open. Some gates open if a high voltage is applied to them, whereas other gates open if the voltage is low. What may help explain things in a fun way is Zachtronics video games. Engineer of the People: Fairly low level transistor-level shenanigans. TIS-100: The assembly-language coding game nobody ever asked for. Shenzhen I/O: Cheap Chinese Gizmos: The Video Game.

First, Beresheet is on its way. SpaceX has done its part, it's now up to SpaceIL, SSC, and NASA (the latter two being involved with the communications aspect of the mission). Second... not everything is "KSP in real life". As point of fact, the vast majority of things are not KSP in real life. Most things that go into space are very well thought-out and carefully engineered. Even the "small" efforts like Beresheet and Copenhagen Suborbital are very thorough efforts by a large number of very skilled and knowledgeable people.

Radio astronomy comes from the big giant radio dishes in Dmagic Orbital Science. These are the ones that unfold to something like 50 meters wide.

Oui. You're probably going to see veteran players over-represented in this poll, though, so your statistics will be off. Unfortunately, like many games this complicated, things will slip through the cracks for new players as the game attempts to gently feed them with a fire hose, instead of the entire city's water output at once.

It's an iron-nickel-chromium alloy noted for corrosion resistance and resilience to temperature and pressure. It's commonly used in aerospace applications as a result; it's hard to work with, but quite robust.

Nothing special, necessarily, but: Test Flight gives unused engines with 0 Test Flight data minimum reliability. I was at roughly 60-70% of maximum data on these engines, probably on account of tech transfer from having used earlier versions extensively. By the end, know I was past 90% of maximum data, possibly all the way to 100%.

I'm not yet done with backlog, but this mission was kind of cool. All glory to Agathorn. The goal was to place a test satellite into GEO, using my new-generation Atlas boosters. All of the main engines were upgraded; an AJ10-42 became an AJ10-104, the LR105-NA-3 became the LR105-NA-6, and the LR79 (S-3D) boosters became H1 (Saturn 1 version) engines. Each and every one of them with more thrust, more specific impulse, longer burn times, and higher max reliability... and I finally had a restartable upper stage. Naturally, the first one had the LR105 sustainer fail to ignite, followed by deliberately dumping it into the ocean after clearing the pad. I usually catch failures-to-ignite before I release the clamps, but I wasn't paying enough attention The second time around, I was very careful to make sure all three main engines and both verniers were at full thrust before releasing the clamps. Then the LR105 sustainer suffered a loss of thrust, producing just 50% of normal thrust. I lofted more than usual, knowing that every meter/second of vertical velocity provided by the H1 boosters would be needed for any chance at an orbit. As the core slowly burned through its propellant with TWR < 1, I pitched up, first to 32 degrees, then 45 degrees, as I watched vertical velocity sink from +900 m/sec, eventually falling to -85 m/sec. But, burn through its propellant it did. Vertical velocity rose, and pitch fell, back down to 32, then 20, then 12 degrees. At this point, I became increasingly confident that the mission could be a success... if the core stage burned to depletion. The LR105 was rated to burn for 5 minutes 50 seconds, and the verniers for 6 minutes. It was now minute 9, and Test Flight's predicted chance of engine failure began to soar. I needed those last few seconds of LR105 burn time. While the margins were generous... they were not so generous as to permit the loss of over a kilometer per second of delta-V. Twenty seconds. Fifteen seconds. Ten seconds. Eyes on the Test Flight display. Five seconds. T = 10 minutes, 25 seconds, and nominal burnout from LOX depletion. MECO. Stage separation. Second stage ignition, and that AJ-10 was A-OK. While the satellite had to complete the last 250 m/sec of the GTO burn on the second pass, it had more than enough hydrazine reserve to still make it all the way to GEO with a healthy remaining delta-V margin.

Well, I can't say this was unexpected. Every dollar spent on trying to communicate with Opportunity is a dollar not spent on many other worthwhile NASA projects, and it's been becoming increasingly clear that we're not likely to get Opportunity back. It's been a good run for a rover whose design goal was a mere 90 sols of operation. Beyond the mere science, the "rover that wouldn't quit" has become something of a cultural icon, a legend in the history of space exploration.

This bit is being taken out of context. Except for the 3-line header, no part of this is about Blue Origin; it's about issues between Bezos and a man named Pecker, who runs the National Enquirer. Still, Blue Origin is out ahead of literally everyone except SpaceX, has what appears to be a more safety-conscious culture, and Jeff Bezos has deep enough pockets to ride out many years of not being the top competitor. After all, even in this era of Falcon 9 being incredibly popular as a launch vehicle, nobody's yet folded. ULA, Arianespace, Roskosmos, ISRO, JAXA, China: they're all still flying, often with commercial payloads. Northrop Grumman's even throwing its hat into the ring with OmegaA.

The orbital elements don't need to be terribly similar for the intercept. All that matters is that: You have a close approach You have enough delta-V to kill your relative velocity at the intercept The intercept is not so incredibly fast that it's hard to get an accurate velocity matching maneuver. A 40 m/sec relative velocity is easier to eliminate than a 4000 m/sec relative velocity. The orbital elements will match up quite well once velocities are matched. Before that point, a near match helps, as it'll reduce the magnitude of the velocity matching maneuver, but it's not strictly necessary.

Going to clear some more backlog... It can be hard to get a good shot of LES jettison, since they have such a high TWR. As is my custom, it separates shortly after second-stage ignition. First unmanned lunar landing of the career: Pioneer 1 approaches Venus This happened to Cheryl Taylor. Twice. Fortunately, the second time, she was close enough to orbit to finish circularizing on the service module. For my second GEO constellation, I decided to send all four on the same rocket and do the whole "transfer bus at 3/4 day period" trick. Another Pioneer probe swings by Mars This rocket was known in development as "Titan 1", and later renamed to "Titan Fun". Pioneer 3 on its kick stages, heading to Mercury.