DerekL1963

I was checking my settings, and clicked to enable MechJeb targeting... and now, none of the ScanSat windows will open (the menu or the instruments), and none of the instruments will respond. I've also lost access to science instrument windows on all vehicles. Closed and restarted the game, and the condition persists. Looking at my log I see a ton of "[EXC 22:19:34.838] MissingMethodException: Method not found: 'MuMech.GLUtils.DrawMapViewGroundMarker'. RenderingManager.OnGUI ()" and "MissingMethodException: Method not found: 'MuMech.GLUtils.DrawMapViewGroundMarker'. at RenderingManager.OnGUI () [0x00000] in <filename unknown>:0 "

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I remember that. But they did not have cheap launches. If they could have sent 10 probes at same costs than one before, failures of single crafts would not have led to failures of missions. Only reason why they use hundreds of millions to ensure that probes are perfect is that launch costs in any case hundreds of millions. I am sure that if launch costs drops to one tenth or less there will be cheaper probes and some kind of "mass production" of probes. Launch costs are a very small fraction of the cost of a typical probe delivered to it's destination. That's the fallacy of cheap access to space. The reason they spend hundreds of millions is because the instrument must operate nearly perfectly for months to years, to very high tolerances, in an extreme environment, after being exposed to the vibrations and shock of launch, and after being untouched by human hands for months and years - and they must be extremely lightweight. It's the last that's critical, because if you can increase the mass available to an instrument you don't have to be quite so clever in how you engineer it to match the other preconditions. Lowered launch costs only significantly lower the cost of the probe only if means you can buy a cheaper launcher with a larger payload.

That's what people have failed to grasp about the Senate Launch System - it's overt and primary mission is to funnel cash and jobs into contractors and congressional districts. It's not the next generation of space exploration and was never meant to be except as an unintended consequence and in press releases.

Is there anything save breaking in here? Or do they just drop in and replace existing stock tankage?

Given SpaceX's rather spotty record of launching on time, and equally spotty record of putting new developments on the pad in time, I wouldn't bet the rent money. Plus Elon announced a delay in the Falcoln upgrades just yesterday. Seriously, kunok's right here - folks need to get a grip.

0.o If the problems were even remotely comparable, you'd have a point. (Hint: Airplanes don't start with fuel floating freely in their tanks.)

No, it's not much of a problem once you're rotating. The problems come during spin-up and spin-down. And how exactly is gravity induced ullage a benefit? Spin ullage pastes the fuel to the walls of the tanks, and when you spin down to maneuver it won't be pasted to the walls anymore. The Apollo spacecraft spun very, very slooooooowwwwly. Around .1RPH(our). A very small fraction of the speed required to generate even fractional-G (say lunar gravity) in any reasonable sized spacecraft.

Actually, the first mobile telephone was deployed in 1946. The first depiction of a personal portable communications device in fiction was in the same year, and that device would be upgraded with video capability the year before Star Trek aired. The guy who actually developed the handheld may have been inspired by Star Trek to do so, but given the general curve of technology only a fool or a blinded fanboy would believe that it wouldn't have happened without Star Trek.

You see that in the design of the JimO probe as well... If the radiators extend beyond the shadow, they can reflect radiation from the reactor back into the shadowed region.

Power, data, GOX, potable water, grey/black water... that's about it. Power and data go via slip rings (another very old technology), only the GOX and the water need to go via swivel joint. And if you're clever about your ventilation design, you might not even have to transfer the GOX.

The article is a nice bit of SF 'what-if', but it's an open question as to how well it's grounded in reality. The folks I know who do this stuff (NASA shuttle folks and private sector folks who write flight software for a living) are very, very, skeptical of the article's breezy claim that the software is easily adapted. It's not just a matter of substituting Columbia for ISS as a rendezvous target. Low inclination orbits have a different ascent trajectory, and the abort options and boundaries are different. And Atlantis's crew would have to be trained on the new procedures on a timeline much shorter than usual. And that's on top of the issues that Nibb31 mentions.

Swivel joints are early 1900's technology. (Battlewagons used them to transfer hydraulic pressure from the ships structure to the rotating turret.) So long as you avoid transferring cryogenics you should be fine. I think you'd be better off retaining fluids in the rotating section though, they can be pumped about to maintain balance and stability. Yes, so the spin would have to be checked and adjusted periodically. . And it's also a primary argument for rotating the crew quarters rather than the whole ship... When you rotate the whole ship, you're rotating about the long axis, which is inherently unstable. It wants to spin along along the short axis. When you spin the crews quarters, you're spinning about the short axis, which is far more stable.

Which is a completely meaningless comparison because it's a useless figure-of-merit. The proper comparison is the energy needed to spin up the wheel section vice the energy needed to spin up the entire ship. In the same manner, the problem with spinning the fuel tanks isn't the inertial forces generated by the spin (which, just in passing, are in a different direction than those experienced at launch), it's the inertia and sloshing of the fuel as the vessel is spun up.

From the point of view of performance and technological availability, yes. From the point of view of budget and political complications, not so much. But NTR has the virtue of actually existing.

It's not at all clear the rotating the whole craft "keeps it simple", given the enormous energy you'll expend spinning up the bits that don't need to be spun and in fact cause problems when they're spun (E.G. your fuel tanks and the contents).

Actually, we need to wait until VASMIR engines with sufficient thrust and sufficiently light power supplies have been developed. We're nowhere near either. VASMIR is basically a very fancy ion engine, and even in "high thrust" it doesn't produce very much thrust at all. (The 200kw system intended for testing on ISS only produces a pound or so of thrust.)

I would have to see a citation on that. Forty years of studying the space program, and I've never heard that. Nor does it make much sense as the Federal budget for '67 (the last year of the huge cuts) was already set by the time of the fire and the AAP already essentially dead. It hung on, with no money, in NASA planning for a couple of years longer which often gives the impression that it lasted longer than it did. (It took NASA decades to realize the 'glory days' weren't coming back and they continued to act/plan as though their return was just around the corner.)

A huge grain of salt. Because, as with most things written about SpaceX, there's more than a little fanboyism involved and less than a little understanding of the situation involved.

Seals (there are many well proven varieties to choose from) and accepting a small amount of leakage as the price of doing business.

Does the learning system detect ass-over-teakettle tumbles? That seems to be cause of most of my losses, the vehicle flipping because the first turn is too agressive.

Not quite. In particular, while rovers had been studied in early 60's the whole thing was mostly shelved by the mid 60's. (Due to a mix of budget concerns and LM weight concerns.) Development of the actual LRV didn't start until 11 July 1969. What was cut after Apollo 1 was the originally planned sequence of test flights before proceeding with the moon landing. In particular, the E mission, which would have been a test of the CSM and LM in high earth orbit. And keep in mind, the original Apollo program wasn't a lunar landing program - it was a general purpose spacecraft that could have been used for a variety of missions. In the midst of Mercury (which is when Apollo was born) NASA really wasn't sure where it was going next or when so they left their options open. But the original general purpose Apollo was only around for a year or so before Kennedy's speech changed everything.

Why did they bother with basing it off the descent stage? I get the ascent stage, so that they could reuse the control spaces for the telescope, but what doe the descent stage have that can make a Telescope Mount cheaper? I thought they just had the thing controlled from the ascent stage, and the descent stage was just replaced by the scientific payload? The LM descent stage structure carried all the structural loads and transferred them to the SLA (Saturn Launch Adapter) via the landing gear. (If you look at the diagrams in the link above, you can see where they retained a small portion of the landing gear for this purpose.) Up until the S-IVB was jettisoned, all the telemetry for the LM went through an umbilical that ran from the descent stage to the SLA. (After that, the crew had to enter the LM and power up the communications system before Mission Control could receive data from the LM.) On it's own the ascent stage had a very limited lifetime, and the descent stage contained the lion's share of the LM's consumables (batteries, O2, and water for the evaporative cooler).* So they could modify the ascent stage and/or modify the CSM while also having to engineer a scientific package from scratch (that would still have to carry out most if not all the functions of the descent stage), or they could just re-use the existing systems (already flight qualified and for which a production chain already existed) to the maximum extent. This is a bigger consideration than it looks on the surface, because by the time significant work started on the LM Lab in 1966 NASA and Apollo's budget had already been cut** and the medium term future of Apollo Applications and the Apollo Program was in some doubt. * The ascent stage was so weight critical (partly for normal ascent but also for aborts) and so cramped that on the later (long stay) missions food, LiOH cannisters for the cabin, and supplies for the PLSS were stored in the MESA on the exterior of the descent stage and had to be retrieved while they were moonwalking. ** Contrary to popular belief and urban legend, not only did Apollo not have a blank check - it wasn't Nixon that killed it. The Apollo program was essentially capped due to the budget cuts of '65-'67. The only bits of Apollo Applications that survived were the long stay LM's, the Lunar Rover, and a very financially constrained Skylab.

You need to be careful of extracting lessons from KSP. It's first and foremost a game, and only in a very distant second place comes being a low fidelity engineering simulator. That being said, this is being proposed and discussed as a propulsion system for an RLV, where engine weight matters a great deal there as it dominates vehicle weight by a wide margin. In this case, even if it was an ELV, weight matters because you're spending so much of it for a system that's really only useful for a short period of time. Dead weight doesn't impact payload on the first stage as much as it does on later stages, but it does have an impact. If your SRB is blocking your main engines... it's probably a waste of time. Unless it's a smallish rocket and a biggish SRB, you'll lose most if not all of your already modest velocity advantage while your mains are starting up. And the O-ring issues that doomed Challenger are long since fixed. No need to avoid joints since doing so only (very) marginally increases safety and (very) greatly impacts total possible performance. (And it's not 'my' aerospike, I was just pointing out where he was losing a lot of efficiency.)

Not quite, it was based (very, very loosely) on the LM descent stage. It's called the Apollo Telescope Mount because it was a descendant of an Apollo Applications Program proposal which would replace the descent and lunar surface equipment in the descent stage with telescopes and scientific equipment that would be operated from within what used to be the ascent stage. (Not that anything survived from the LM design in the flown ATM mind you, the name just stuck around out of inertia.)