Nevertheless, NASA is part of the executive branch of the United States. Whatever the President says is the official goal of NASA, so that’s what they work towards.
I’m happy to be corrected! I must have been recalling the series of announcements by individual airlines about their last 747 flights, over the past two years or so. Good to see Lufthansa and British Airways still fly ‘em.
No rocket has matched the low Earth orbit payload capacity of the Saturn V but there are plans for a Space X rocket to surpass it
It was the last 747-100 (original variant) that was retired last year (https://airlinerwatch.com/the-oldesr-boeing-747-in-service-says-goodbye-to-the-skies/amp/), from engine testing service with GE. This variant first flew Feb 9, 1969.
Still some -200s and especially -400s still flying: List of Boeing 747 operators - Wikipedia
NB
As far as I know, none of the NASA concept missions have been single-launch.
You’re probably thinking of the Altair concept, which dates back to the Ares V days. Even it was a multi-launch mission: the Altair lander would launch on a Ares V, and the crew would launch on the Ares I and rendezvous in low earth orbit.
The current Artemis program is even more ridiculous: build a “gateway” space station in an eliptical high orbit around the Moon, dock a lander, and fly the crew to it using an SLS-launched Orion. The whole thing is basically designed around the inadequate capabilities of SLS and Orion, which can’t otherwise make a trip too and from lunar low orbit by itself. (My one tiny shred of hope around this whole boondogle is that the Lunar Gateway is going to be built from general-purpose modules that might be the basis for something more useful, like a Mars transfer vehicle.)
Fully fueled, the LM only weighed 7 tons. The Saturn V had the ability to put 150 tons in LEO - a requirement as the third stage - with fuel, was required for TLI.
Saving 10-15 tons (LM plus the required third stage fuel, fairing etc.) wouldn’t have made the Saturn V much smaller. You would then need an entirely separate rocket to launch the LM, which would then have to dock with the third stage for TLI anyway.
Outside of the edit window… My back-of -the-envelope scratchings came up with the Saturn V weighing about 140-150 tons less on lift off, if the LM wasn’t part of the payload.
The Saturn V weighed about 3000 tons at launch so a small savings - 5%.
What did NASA have in their arsenal?
The Titan couldn’t lift 10 tons into LEO - the Gemini payload was about 4 tons. So they would have had to use a Saturn 1B to launch just the LM - which is completely overkill.
I’m sure all the options were looked at by those guys with slide rules.
You need to remember that the Saturn V was being designed and built at the same time as the Lunar mission hardware was. They were both starting with only a rough outline of what the mission parameters were. The S-V was mostly nailed down before lunar orbit rendezvous was selected. The CSM and LM designers were constantly battling moving mass and performance targets as the designs developed, and even then there were revisions that improved performance that were only available in later missions. The Earth orbit rendezvous was going to simply use two S-V launches.
Note, getting the payload onto a lunar trajectory takes a lot more energy that just getting to LEO. The trans-lunar injection burn took about 2/3rds of what the third stage held.
So soon after take off one module separated did a 180 degree flip and docked. Very impressive but to my silly mind the question was why did they not take off from earth already flipped and docked?
I asked Dopers this a few years ago. The best answer, I think, was about the escape rocket — that thingy on top of the Apollo stack that would allow an abort (theoretically) during the first couple minutes of launch. Hard to make that work if the astronauts are upside down and lower in the stack.
The command module has a hatch on one end and the heat shield on the other side. (You don’t want an opening in the middle of your heat shield.) It must reenter and land with the heat shield side down, so it makes sense to launch it heat-shield side down as well, otherwise the astronauts will be upside down during launch or landing.
Also, the command module acts as an escape system in case of a catastrophic failure, so it needs to be in a position where it can be ejected cleanly away from the rocket. The logical thing to do is to place it at the very top, so there’s nothing above it that gets in the way of ejection.
So now the command module is at the top, with the hatch at the top. So it can’t be connected to anything. But no big deal, the command module (+ service module) has the ability to maneuver in space, and the ability to dock with the LEM. So just do one more docking maneuver.
The alternative is a far more elaborate escape system that jettisons everything above the command module first, then let the command module eject. And part of that process is disconnecting the LEM from the command module so it can be jettisoned.
I believe that kind of thinking reflects the needs of earthbound travel, not the realities of space travel. If you have a problem with your spacecraft, you need to fix it now, in whatever orbit you’re currently in, or go home. There’s no point in using the delta-V to stop someplace else unless that was already part of your mission in the first place. Like… rendezvousing with your re-entry capsule. There’s your lifeboat. What needs to be docked with it that wasn’t part of the actual mission plan?
There was some thought that John Glenn’s heat shield was damaged. NASA elected not to tell him. There was a method for shuttle crew members to inspect the tiles before reentry. There are two examples of why you might want to have a spacecraft available that could get astronauts home.
You may have been reading articles noting that, as of 2017, there are no U.S. airlines still flying the 747.
It’s not like flying airplanes in formation. There isn’t any wind or turbulence. When they undocked the command module, the two spacecraft were effectively hanging motionless relative to each other.
Right. Nevertheless, the aerospace industry is skeptical. As the saying goes: “No bucks, no Buck Rogers”.
Yes, it’d be nice to have a spare reentry-capable spacecraft for emergency use. But if you didn’t launch it with your original vehicle, then how do you get to it? It’s not so simple as “space is a place, and so if you’re in space, and the lifeboat is in space, then you’re close to the lifeboat”. Space isn’t a place; it’s a whole lot of places, and it’s in general very hard to get from one of those places to another.
The article makes a crucial point about the obsolescence of the 747. Both it and the Airbus A380 - which is a much more modern base design - are essentially obsolete for the same reasons. The business has moved on from spoke-hub routes, and passengers now tend to fly much more direct routes. It isn’t so much that either plane is technically obsolete, but for the market, things have moved on. The 747 remains a backbone of international flights out of Australia on Qantas - but the new non-stop Perth-London route (as well as the non-stop Melbourne SanFransico, and Brisbane - LA routes ) are all Dreamliners. Airbus bet on spoke-hub but it has not really panned out for their massive investment in the A380.
ESA have a similar problem with the Ariane V. It is too big for most commercial mission payloads. They put a lot of work into being able to loft two satellites at a time, but its successor will be a smaller rocket, designed around the sweet spot in the launch market.
The Ariane V is a very reliable big rocket, and its big ticket task very soon will be to launch the Web Space Telescope. When you have over 10 billion dollars worth of payload you want to get it right.
Everyone is skeptical. All I’m saying is, NASA has no choice but to make a good-faith effort to meet the 2024 goal, with whatever resources it has available. NASA can’t just say “no, 2024 is not realistic, so we’re going to ignore that deadline, and work with SpaceX to develop a reusable lunar spaceship instead.”
I thought Buzz Aldrin had that figured out.