Starman4308

These two quotes mostly agree with my understanding of what caused the LOV (Loss Of Vehicle) event. Management pushed for a launch below the temperatures the Space Shuttle was designed to operate at, having ignored prior warning signs that the O-rings were being pushed beyond their specified intent. As a consequence, a seam burst, a fortuitous oxide seal formed, but that was eventually torn off by windshear, exposing the main tank and support structure to SRB plume, culminating in a strut failing. They do not, however, address what transformed the Challenger LOV event into a LOCV (Loss Of Crew and Vehicle) event. While it is possible that that long report contains something I'm unaware of, fundamentally, my understanding is: The Space Shuttle was a novel and largely untested design (orbiter placed on the side of the tank and boosters, instead of a vertical stack). Orbital launch vehicles, even today, are largely experimental vehicles with margins far slimmer than even jet fighters, most of which have an abort mode (ejector seats). No abort provision had been made for large sections of the launch process. Even after Challenger, SRB failure was a guaranteed LOV with near-guaranteed LOC. There is a very substantial chance that had a conventional LAS been provided, Challenger's crew would have survived the event. A later disaster, Columbia, was fundamentally caused by the design of the Space Shuttle; with a conventional stack, foam could only have struck glancing blows to crucial components of the launch vehicle, nevermind the reentry vehicle that is physically above all the insulation foam. Remaining issues such as tile loss were never addressed, with NASA just hoping it didn't cause a failure. The behavior of conventional, vertical stacks is far better understood thanks to the sheer number of unmanned launches. In the cases of both Columbia and Challenger, if you replaced the Space Shuttle with a Space Launch System/Orion, the crew would very likely have survived. In the case of Challenger, there is an abort tower to permit crew abort from T=0, and my understanding is that Orion would have stood a very good chance of separating for a safe parachute landing. Not guaranteed, but a heck of a lot better than "have to hold onto failing SRBs and pray". Mission failure, but crew survival. In the case of Columbia, unless gravity magically reversed itself, falling foam would not possibly have hit the Orion vehicle. It would have been a non-incident, and today we would have been blissfully ignorant of foam's capacity to punch through aluminum wings. Now, it is possible the SLS has design flaws that the Shuttle didn't. We may never find out. Unlike the Shuttle, though, SLS-Orion, Falcon 9-Dragon, Atlas-Starliner, and Soyuz all have functional and relatively simple abort modes, and are based on the well-understood architecture of "put something on top of a rocket". While they all have some flaws, and likely have undiscovered flaws, major failures of launch vehicle components need not doom the crew.

A faulty management decision that only killed astronauts thanks to a faulty design that had no abort mode for much of the ascent. That the managers messed up does not absolve the design's failure to have a robust abort mode on an experimental craft. Granted, the Shuttle was halfway designed by the managers, with the engineers just doing what they could under far too many demands.

From the cargo end, why send up replaceable cargo on an expensive man rated vehicle? Better to send that up on something cheaper, even if it doesn't reach the extreme safety requirements of a manned vehicle... and send up the astronauts separately.

Let's put this into perspective. The overall cost of the Shuttle program is estimated at $196 billion (2011). This gives us a per-launch cost of $1.45 billion. For each launch, they could put 27500 kg of payload into orbit, 7 crew, and 68,585 kg of dry mass. Per kilogram of payload put into a permanent orbit, that's $52,727 per kilogram. Per kilogram of payload and dry mass (excluding only the 10 tons of SSME), that's $16,863 per kilogram... and I suspect a good fraction of that dry mass was not very useful for extended in-orbit capabilities as a "mini space station". Compare that to the 20,520 kg payload and $153 million cost of an Atlas 551. $7,456 per kilogram placed into a permanent orbit. Compare that to the estimated $405-653 million to put a CST-100 Starliner or Crew Dragon into orbit. To match the max payload and dry mass of a Space Shuttle, you're talking about $641M for cargo and $653M max for the crew. Even under ludicrously favorable assumptions such as "every kilogram of not-SSME is equal to a kilogram of payload placed in permanent LEO" and "every crewmember put into orbit was really needed in orbit even for launching a commsat", the Space Shuttle was an overly expensive HLV... and as a crew launch vehicle, it was an unsafe disaster. While I would like to fondly reminisce on something that got cancelled before I got interested in spaceflight, and talk about some of the fun missions it carried out, I've been stuck trying to continually point out (and not necessarily to you) that it was, as point of fact, a trainwreck from day 1. Incidentally, the link above, https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20170008895.pdf , is a good read on the commercial launch services program.

I would argue that the whole project was conducted under a level of political pressure and optimism that led to failures at every level, from the initial design work all the way to the actual flights. For example, while the proximal cause for the Challenger disaster was a management issue of ignoring the engineers, the proximal cause is just one element of the disaster. If I may make a brief analogy, some blame the loss of the Japanese aircraft carriers at Midway to a single scout plane's failure, but why that allowed all 4 carriers to go up in flames takes an entire book to describe. A brick of statements below: Overall, the Shuttle was dangerous and expensive, and for the huge sums of money invested into it, we could've had a much more impressive manned space program than we did. There was no reason to haul up life support and a mini space station every time they wanted a communications satellite in orbit: put that on an ordinary cargo rocket, get it up for a fraction of the price, and redirect the savings to put up a permanent space station in orbit. That astronaut killer sucked up far too much money over its lifetime, decades of potential progress dedicated to an overly politicized X-plane that had been promoted as a reliable space truck, despite relying on a swathe of unproven technologies. Cargo and crew should, from here on out, be strictly separated. All the scientific equipment and extended life support capacities of the Shuttle could have been more cheaply sent up on a separate rocket, to which a conventional capsule could have docked.

On mobile, so not a full post, but does that article give any info on how much NOx comes from the hydrolox engines, and how much from the SRB, with its ammonium perchlorate that has all the necessary atoms? EDIT: @Pand5461 , here's the breakdown of the obvious sources of those gases. Water: primarily the SSMEs, but also the hydrogen and oxygen in ammonium perchlorate, which is (NH4+)(ClO4-), plus hydrogen and oxygen from the PBAN binder. Carbon dioxide: Mostly the PBAN binder. Aluminum oxide: powdered aluminum from the SRBs plus the oxygen. Hydrogen chloride: the chlorine from ammonium perchlorate has to wind up somewhere. Carbon monoxide: PBAN binder. I'm surprised there isn't more carbon monoxide: from a rocket performance perspective, you want lighter carbon monoxide than heavy carbon dioxide. That's a big part of why hydrocarbon-oxygen rockets are run fuel-rich. NOx: Nitrogen from the ammonium ions and the cyano groups in PBAN (and isn't that a fun thought). Oxygen from perchlorate and PBAN. Not seen in this breakdown is N2. Overall, this has been enough to convince me that there is some environmental impact from firing large-scale solid rocket motors, though it's probably still not as bad as the hypergolics. While orbital launch consumes a small fraction of what the military and amateur rocketeers use, there's the issue that orbital launch vehicles generally have low TWR, so you're putting a lot of exhaust into a small area for a fair while until it's far off the pad.

With regards to building a new space station, while the Space Shuttle did help somewhat in bringing up a sophisticated manned platform for the initial construction, I don't really see any reason why we couldn't send up modules on an expendable heavy lift platform, much like how the Russians sent up their modules on Proton and Soyuz rockets. The Space Shuttle was convenient for the ISS courtesy of having an at-the-time unmatched payload capacity and crew delivery capabilities. While none of the upcoming systems save perhaps the SLS have the same combination of crew capacity, heavy payload, and auxiliary equipment like the Canadarm, that is merely convenient, not necessary for building a space station. The Falcon 9 in expendable mode comes close in payload mass, and the Falcon Heavy exceeds it, although its fairing volume leaves something to be desired. The Delta IV Heavy, so far as I can tell, is pretty close to the capacities of the Space Shuttle, and the New Glenn should just blow the Space Shuttle away (which is part of why I'm so excited for New Glenn). All the equipment that made the Shuttle unique can be duplicated; a robotic arm could be included with the first space station module, etc. I see no reason why, with a little bit of creativity, conventional launch vehicles could not be used to replace the ISS... and it's got to be better than paying out the nose for the overly expensive Shuttle launches. For other missions such as returning payloads from LEO... just put a heatshield and a small maneuvering unit on the payload. Ask the Air Force to put it on the X-37. Sierra Nevada would probably love to put it on the Dream Chaser. The Space Shuttle had numerous capabilities, yes, but a lot of them were wasted on all the flights where it just acted as an outrageously expensive HLV, and the rare missions where the unique capabilities of the Space Shuttle really shined... probably could have been done more economically by sending up a custom mission module on a separate unmanned vehicle, and sending up any necessary crew on something smaller and less deadly. EDIT: To further clarify a point, the New Glenn's gigantic 7 meter fairing is filled with my hopes and dreams for an ISS replacement. It's a pretty large fairing.

They almost look like Christmas bells wrapped up like that. I wonder how much money I'd owe Rocket Lab if I decided to ring one... Anyways, best of luck to Rocket Lab, and to orbital launch providers around the world. Hopefully we're in for a new age of (relatively) cheap space access.

They probably thought about it. I believe NASA wanted liquid fueled boosters, but was overridden. The Shuttle program was a train wreck from start to finish. Nothing was the way the Shuttle was originally intended to be, a compromise solution for many different groups with mutually contradictory goals. In terms of safety, you had jawdroppers like insisting the SRBs had gimbal for the minute possibility of issues with SSME gimbal, and no plan for SRB failure. Could have. Should have. Didn't, and astronauts paid the price for it.

Because they couldn't. The Orbiter and External Tank at liftoff massed on the order of 850 tonnes. The SSMEs provided about 5250 kN of thrust at launch. That is a TWR of less than 1.0. The first abort they could possibly begin was an RTLS, that begins at SRB separation. There was no abort plan for SRB malfunction because the Shuttle simply couldn't safely abort until after they had burned to depletion. And in this case it isn't. Between "overly expensive and dangerous" vs. "much cheaper and safe", you're choosing the "overly expensive and dangerous" option.

Yes, something that clearly happens all the time, because we know air travel is the most dangerous form of transportation out there. Oh, no wait, it's the safest per passenger-mile. Your disingenuous insult is also very easy to say when you're not the one climbing into a vehicle with a 2/135 failure rate, when you're not the one authorizing those launches, when you're not even the guy inspecting the heatshield for defects. We know space travel is risky, but that's no excuse for asking astronauts to fly in inherently flawed vehicles, nor is it an excuse for asking the American public to pay for disproportionately expensive orbital launch vehicles. You seem obsessed with the fact that there's been a gap in US orbital capabilities imposed by cancellation of the Space Shuttle program, and ignore, twist, or misrepresent all other factors towards that singular fact. The gap itself was caused when the federal government approved an inherently flawed and overly ambitious space transport plan, and it lasted so long because the federal government couldn't make up its mind on how to replace it, with the Ares program followed by SLS, with a few bucks thrown towards actually reasonable proposals to restore LEO manned capability. Had there been actual determination to restore manned spaceflight capacity, there would have been essentially no gap. The underfunded commercial crew delivery program will almost certainly be sending up astronauts either late this year or early 2019, and was started in 2010. 9 years from the Columbia disaster gets you to 2010, a year before the Space Shuttle was retired. "My God, Thiokol, when do you want me to launch - April?" Yes, I want you to launch in April, if that's what it takes for the mission to succeed. EDIT: On a much lighter note, the sheer absurdity of the Armageddon scene made me do the math: even with a cargo bay filled with extra OMS fuel, I'm pretty sure they couldn't have managed more than 1400 m/sec of delta-V out of the OMS, which would be nowhere near enough to hit Earth escape velocity, nevermind turn back around and manage a 0-velocity rendezvous with an asteroid. This, I'm sure, is the only glaring inaccuracy in the entire movie.

V∞ is only one application of the Oberth effect. The Oberth effect is the simple observation that, in whatever reference frame you choose, a change in speed produces a greater effect on kinetic energy if the speed is already high. Orbital mechanics does not play into the Oberth effect. What almost everybody refers to with ΔV is a craft's ability to propulsively change its own velocity vector. That you can accomplish more or less with that ΔV depending on gravitational assists and the Oberth effect is immaterial; a craft's ΔV is solely a function of full mass, empty mass, and exhaust velocity. That is the definition used by almost all rocket scientists and KSP players, and adoption of this terminology will make things much easier to discuss. Otherwise, you are simply talking past everyone else, irritating those who know what they're talking about, and confusing new players who don't know what is being talked about. As to that Science Channel show you're discussing: material presented for a general audience is often rife with oversimplifications and lack of technical correctness, and they could have been referring to just about anything.

You are misrepresenting his point here. He's not claiming the astronauts could have survived the Challenger disaster with the Space Shuttle as it was. The logic is that if the Orbiter had been replaced by a conventional capsule-with-LAS design, that capsule would have stood a great chance of getting out intact. The Orbiter was doomed by its design, which put the crewed vehicle on the side of its propellant and two SRBs, and had no abort mode for failing SRBs. Had the ground crew or Shuttle crew decided "okay, we need to abort now"... they could not have aborted until the SRBs burned out, because the earliest abort past a pad abort was an RTLS after SRB burnout. A conventional stack, on the other hand, the LAS could have been fired off, separating the crew from the failing SRB. The exact same SRB with the exact same circumstances and exact same launch pressures would not have doomed Challenger's crew if there was a functional abort mode. That's the advantage of the conventional pod-with-LAS: no matter what happens to the extremely complicated launch vehicle, the crew is still alright if a much smaller and simpler abort system functions. The Shuttle didn't have that, and that killed several astronauts. While a LAS would not have saved Columbia's crew (as the foamstrike damage was not discovered during launch), it too was the fault of putting the crewed vehicle on the side of the propellant tank. Debris from the launch vehicle itself caused critical damage to the Orbiter, something that would have been physically impossible if the crew vehicle was on top of the launch vehicle.

The nitric oxides, while unpleasant, are nowhere near as bad as hydrazine and its derivatives such as UDMH... not to mention the amount of NTO* that will be left in the spent stage. The cryogenics, while not perfect, are a lot better than the hydrazine-derivative fuels and nitric oxide-based oxidizers. *A, liquid-fuel rockets generally always still have a little bit of propellant left in the feedlines and bottom of the tank at shutdown. B, just to make sure we're both clear on this, nitrogen dioxide and NTO freely interconvert: if you have one, you have the other, in a temperature-dependent ratio. I'm not hugely concerned about how LH2 is currently produced. While steam reforming is a CO2-emitting process, it's a drop in the bucket next to factories, cars, cattle, etc. In the long run, electrolysis can take over for steam reforming, and in the short run, the carbon emissions from LH2 production are probably dwarfed by the carbon emissions from making the rocket hardware in the first place. Additionally, while there are a few hydrolox first stages out there, it tends to be reserved for upper stages where its specific impulse outweighs the significant engineering challenges of using hydrolox. The environmental consequences I'm concerned about from rocketry are caused by toxic compounds getting dropped either on land (which is bad) or at sea (which is... less bad? Maybe?). Upper stages like the Briz, I'm not overwhelmingly concerned about: they're not very large, and reenter hard, hopefully dispersing any residual hypergolic propellant over a wide area. Lower stages, though, I'd vastly prefer to be handled with either cryogenics or solids. Current or in-development launch vehicles with hypergolic first stages/boosters: GSLV Mk. II (boosters, second stage). GSLV Mk. III (first stage). Long March models 2C, 2D, 2F, 3A, 3B, 3C, 4B, 4C Proton-M Rokot Simorgh? Strela Unha (IRFNA/kerosene lower stages, UDMH/NTO third stage) Current or in-development launch vehicles with hypergolic upper stages: Briz, Fregat, and Volga upper stages (various Russian and Soviet-legacy launchers) Cyclone-4M Ariane 5 EPS L.97 and EPS L10 upper stages Delta II Epsilon CLPS fourth stage Long March 5, 6, 7 third stages PSLV stages 2, 4 Shavit 4'th stage Tronador upper stage Vega upper stage Overall, in compiling these lists (based on a quick scan of Wikipedia), I've found a few things out. First, there's more operational orbital launch vehicles than I thought. Second, while India and China (which have recently developed orbital launch capability) are currently making extensive use of hypergolic first stages, they seem to be developing rockets with cryogenic first stages, though I'm uncertain how much of that is environmental concerns, and how much is just the higher specific impulses offered by the cryogenics. Third, Argentina is developing a launch vehicle and I am utterly surprised by that.

Your opinion on the Space Shuttle's safety does not outweigh operational experience of 2 LOCV in 135 missions. While the individual flaws have been patched, you still had several fundamental safety issues that not only provided ripe fruit for more malfunctions, but also made it very difficult to survive significant malfunctions. More conventional capsules have the advantage of a very simple and robust abort mode that applies throughout launch: shut down the booster, separate from the stack and fire the LAS, and align for reentry. The Shuttle literally couldn't even start an RTLS abort until after the SRBs had burnt out, and emergency reentry was a very finicky business to avoid overstressing the Shuttle's frame. More conventional capsules have the advantage of being on top of the stack: debris from the rest of the booster can't fall onto it, and it's relatively easy to separate from it. Much of the low operational cost in the last years of Shuttle operations was due to winding down of the program, in particular the shuttle improvement budget. Thorough budgetary analyses continue to suggest that the current, commercial approach to spaceflight is several times cheaper than operating the Shuttle would be. That's because I do scoff at including the orbiter in that number. All that space station, laboratory, construction platform equipment, was limited by the size of the fuel cells used to power the Shuttle. In terms of equipment that went up to space and stayed up there, the Shuttle's payload capacity was miserable. For the rare cases where the Shuttle's unique capabilities were extensively used, quite frankly, we probably could've done it cheaper with a single-use mission module sent up separately on a medium/heavy-lift vehicle, to which a small crew transfer vehicle would dock for the duration of the mission.

Under no circumstances could I possibly countenance continuation of the Space Shuttle program. The operating costs were through the roof, and there were multiple glaring flaws with the concept that made it far less safe than any manned space vehicle should be, such as the absence of an effective LAS. The only really unique things that the Space Shuttle brought were a large-volume payload bay and manned capabilities; in terms of payload mass, it's pretty thoroughly matched by the Delta IV Heavy, and will be exceeded by the Falcon Heavy and New Glenn. I would rather have the US go for another couple decades without indigenous human spaceflight capability than risk astronauts in the disaster (and expensive disaster) that was the Space Shuttle. It was a failure as a cargo delivery vehicle due to poor operational tempo and sky-high operating costs (estimated at something in the realm of $18,000/kg). Maintaining "just one" Space Shuttle would make this even worse, since the vast majority of Space Shuttle operational costs were fixed costs that did not change no matter how many or how few launches they made. It was a failure as a human spaceflight system due to numerous design flaws making it a dangerous craft to be in; on top of that, it had essentially no capacity to go beyond LEO, whereas even the "low-capability" Crew Dragon can go for a lunar free return.

It was a rather remarkable and iconic launch vehicle. Perhaps with a more focused development process it could've been an excellent launch vehicle, but it tried to accomplish too many things at once and was unable to accomplish them all. We learned a lot of costly lessons from the Space Shuttle, which have helped inform us as we attempt to fill the many goals of this all-in-one vehicle. An example of the tradeoffs: the USAF wanted it to be able to carry Keyhole satellites, which meant a large cargo bay and payload capacity. That drove development of the very high-performance RS-25, an engine so complex that it probably would have been cheaper just to build new engines to a simpler design each time. Use of this extremely expensive and complicated engine drove up costs, reducing its effectiveness as a cost-effective launch platform. The RS-25 in particular has probably served as an object lesson to SpaceX and Blue Origin, who focused more on ensuring their engines were robust enough for reuse than on extracting every ounce of performance they could out of their engines. The Merlin is an open-cycle gas generator, the BE-4 operates at a relatively low chamber pressure, and the Raptor uses methane rather than kerosene to reduce coking in the engine (something that also goes for the BE-4). That it was a manned vehicle: Might have been necessary for reuseability at the time, due to poor computer hardware and the need for precision landings (though this is to me an argument that the Shuttle was ahead of its time). Drove up refurbishment costs because the parts for a man-rated vehicle have to be very thoroughly checked (not to mention the spotty abort mode coverage). Conflicted with the intent to use it as a cargo vehicle. The cost of everything goes up for a man-rated vehicle, such that it's best to send the cargo up separately in a cheaper-per-kilogram purely cargo vehicle. While there were some remarkable missions carried out by the Shuttle, such as servicing the Hubble Space Telescope and building large sections of the ISS, I'm glad it's retired: it was too expensive and too dangerous to continue flying. It's taken longer than I would've liked, but now we're finally returning to the capacities we once had. The US is now becoming a leading launch services provider, the Commercial Crew Program should transport astronauts to LEO by 2019 (maybe even this year), and between SpaceX, Blue Origin, and ULA, we'll have a variety of medium to heavy launch vehicles to conduct ambitious missions. There's also the Senate Launch System, but the one good thing I'll say about that is that it's probably safer than the Space Shuttle was.

Any of the cryogenics should have vastly reduced toxicity. Kerosene should not be hugely worse than gasoline fumes, and should not be hugely risky to clean up, while methane and oxygen should literally just boil away. I do have a fair bit of respect for why many launch providers avoid hydrolox, particularly for lower stages. The density is very low, causing not just construction but aerodynamic issues (sending the CoM upwards), it's a strong reducing agent, it's very cryogenic, etc. Furthermore, on the engine side of things, that low density means requiring separate turbopumps for the hydrogen and oxygen, and the low density means relatively little mass gets pumped into the combustion chamber, meaning weaker thrust than a similar-sized engine with denser propellants. In any event, though, there is no good reason why China should be dropping multiple boosters and stages with residual UDMH on its citizens; UDMH is very, very toxic. While the UDMH/NTO combination is hypergolic and relatively simple to deal with, bulk uses like this can cause a severe environmental problem.

I'd trust the 45 ton figure more than the 70 ton figure. Based on published thrust values, New Glenn can't be more than about 1400 tons on the pad, for which 70 tons would be a fairly unreasonable 5% payload fraction. Still, even 45 tons puts the New Glenn firmly in the heavy lift category. In general, I'm pretty excited for the New Glenn. While it's not the first highly-reusable orbital launch vehicle, it's arguably the better reusable HLV (Heavy Lift Vehicle) than the other company's reusable HLV, which has severe fairing volume limitations.

On the first misconception, that velocity produces the same change in kinetic energy: We are agreed that kinetic energy obeys this equation: KE = 1/2 m*v^2. Thus, for a 2 kg object: 0 m/sec: 0.5 * 2 kg * (0 m/sec)^2 = 0 1 m/sec: 0.5 * 2 kg * (1 m/sec)^2 = 1 kg * 1 m^2/s^2 = 1 J Thus, by accelerating your vessel from 0 to 1 m/sec, your vessel has gained 1 J of energy. 1000 m/sec: 0.5 * 2 kg * (1000 m/sec)^2 = 1 kg * 1000000 m^2/s^2 = 1000000 J 1001 m/sec: 0.5 * 2 kg * (1001 m/sec)^2 = 1 kg * 1002001 m^2/s^2 = 1002001 J Thus, by accelerating your vessel from 1000 m/sec to 1001 m/sec, your vessel has gained 2001 J of energy. Thus, the same change in velocity, the same delta-V, has produced massively different changes in kinetic energy dependent only on your starting velocity. The reason rockets don't horribly break conservation of energy is that the exhaust loses a commensurate amount of kinetic energy at the same time as the rocket gains energy. On the second misconception, that the Oberth effect lets you get more delta-V: Rockets are fundamentally based on Newton's third law of motion: for every force, there is an equal and opposite reaction force. This produces conservation of momentum, where momentum p = mv. This is, for our purposes, more important than conservation of energy; while total energy is conserved, kinetic energy only describes a portion of your system's total energy. While the concept holds for rockets, it is simpler to consider a vessel propelled by a gun firing discrete chunks of mass. A 1 kg object propelled out the back of a spacecraft at 3500 m/sec will have (relative to the original position/velocity) -3500 kg*m/sec of impulse. Total impulse of the system remains constant: +3500 kg*m/sec of impulse had to be imparted to the spaceship. If the spacecraft (sans the propelled object) masses 100 kg, its velocity will be changed as (3500 kg*m/sec / 100 kg) = 35 m/sec of delta-V. The famous Tsiolkovsky rocket equation is essentially stating "if you propel mass out the back in infinitesimally small quantities, the change in velocity is described by this equation": delta-V = V(exhaust) * ln(full mass / empty mass) = Isp * Gm * ln(full/empty) Exhaust velocity is determined by how fast the propellant leaves the rocket, and is fixed by the engine and what it's using as propellant. Your full/empty mass is determined by the spacecraft design. Both are wholly independent of how fast you happen to be traveling right now and in what reference frame. If you're going 100 m/sec relative to Earth or 100,000 m/sec, you still have the same delta-V. The amount of change kinetic energy that delta-V affords you, however, is hugely different based on the Oberth effect... and it is energy that one needs to escape a gravity well.

While not quite "rearranging deck chairs on the Titanic", that's still far from enough to salvage SLS as a useful vehicle. It's still using way too many subcontractors, the ludicrously expensive RS-25 engines, and will have a poor operational tempo, leading to high program costs just to keep people employed. Still, in the event that the SLS somehow gets funded for more missions, Blue Origin has an excellent engine for the upper stage. For that matter, the BE-4 would make an excellent first-stage engine to boot; while it doesn't have the same specific impulse as SSMEs, the BE-4 is more powerful and almost certainly less expensive. Of course, down that way lies another round of Congressional interference in redesigning a bad idea. I'm now wondering what the New Glenn would be able to do with a couple Space Shuttle SRBs strapped to the side and I'm giggling. With respect to the article itself, it said "but the 150,000 lbf figure is for vacuum use". I'm curious as to what mission profile the author of that article envisions where the SLS upper stage would be firing against significant atmospheric backpressure.

@Snark is correct on the Oberth Effect. It's a consequence of kinetic energy (in the classical limit) being proportional to the square of current velocity. For a 2 kg test object: 0 to 1 m/sec is a gain of 1 J. 1000 to 1001 m/sec is a gain of 2001 J. The Oberth effect is essentially stating that a change to your velocity produces greater kinetic energy changes when you are going fast. This benefits maneuvers at periapses, where velocity is highest, or otherwise deep in gravity wells. It's why high TWR burns are more dV-efficient, because you can complete the requisite velocity change while giving the gravity well less time to reduce your velocity.

I'd been skeptical for a bit of the in-situ gas harvesting schemes, because you'd want to fill up the balloon before you got so low down in Venus's atmosphere that you're roasting the equipment. One thing to think of, though, goes back to helium. For such a scheme, it wouldn't have to stay in the balloon long, it'd just have to stay long enough to produce lifting gas in situ. You could use a relatively lightweight initial charge of compressed helium to initially inflate the balloon (and probably dump the tanks), and then stay up on those while harvesting solar energy to either convert CO2 to CO, or possibly separate out nitrogen.

As usual, work backwards through the mission. Design something that can return the crew (if any) from Jool. Beneath that, have something to do everything you want to do in the Jool system. Beneath that, have your Jool transfer stage, etc. Mission, then payload, then vehicle.

And we have a scrub, with a new attempt tomorrow.