Chapter 353 - 345 Reuse or Not Reuse_1

Expanding the International Space Station is a major project.

First of all, the ISS is an international collaborative project, and it truly lives up to its name.

While NACA has a profound foundation in deep-space exploration and astronautics, it is not adept at the construction of large-scale in-orbit spacecraft.

The reason can be traced back to the last century’s space race; after America’s victory in the Apollo program, it became somewhat complacent, not caring much about launching just a few modules into low Earth orbit.

Of course, it’s not that NACA had no interest in long-term manned missions in low Earth orbit—in fact, this project was already included in the Space Shuttle program.

The first Space Shuttle to be commissioned, the "Columbia," should actually have been called a space laboratory rather than a mere shuttle, as its cabin was outfitted with considerable experimental equipment, and it lacked the later shuttles’ retractable cargo bay, being able to stay in orbit for extended periods on its own.

Besides, a single Space Shuttle weighed more than a hundred tons, larger than the Union’s initial space stations.

And upon realizing that its national power was insufficient to support another moon landing, Russia chose to build near-Earth orbit space stations, accumulating substantial experience.

The International Space Station initially began as America’s project, with the intent of including its European partners—even considering going it alone—but due to a lack of experience and a radical budget cut following the Cold War’s end, it ultimately had to bring Russia on board.

Over the years, during occasional quarrels, Russia would threaten to "divorce" the ISS, because if the ISS were to lose the functional support of Russian modules, it really couldn’t survive...

Even with the expansion, Russia’s opinion couldn’t be ignored.

Before convening a meeting on the ISS, Montal discreetly reached out to the Rusia Space Agency to get the lay of the land, and the feedback he received was noncommittal.

Yuri Borisov, through RT, delivered a lot of gibberish, but after careful consideration, Montal could only make out two words: want money.

Because it couldn’t join the current moon race, the Rusia Space Agency inadvertently became a coveted partner. A few days ago, they announced they would engage in a series of space station cooperations with China, following the docking of the Italian and French jointly-developed modules with the Tiangong Space Station.

Of course, the specifics were also unclear, as they were essentially waiting to drive a hard bargain.

Now, for the ISS expansion to proceed with Russia contributing, the money had to be in place, even though the primary truss section required the Space Shuttle.

Montal was helpless in this regard; Russia really did have a hold on the Achilles’ heel, after all, NACA couldn’t just build another super space station willy-nilly.

But as the March was gradually taking shape in space and getting closer to its full form, the Senate grew increasingly dissatisfied, insisting on the expansion.

Not only was expansion necessary, but it also had to be advanced—even if it couldn’t match the staggering mass of the March, it still needed some standout features to publicize.

...

"Four RS25s, or three RS25Es?"

Rockdain and Boeing’s teams gathered together to discuss the engine selection for the new Space Shuttle system.

Replacing Endeavour’s three massive RS25 engines with nuclear ones wasn’t too challenging; JFT had already provided the data on the engine sizes they were actively producing, and there wasn’t a significant difference.

Some adjustments were needed for the center of gravity, but fortunately, the Endeavour had been stripped down to its frame for refurbishment, and with the help of modern computers, this could be overcome.

The problem lies in the launch system.

The original Space Shuttle’s launch system was quite unique. During launch, the shuttle lay atop a huge orange fuel tank, feeding fuel to its three RS-25 engines at the tail, flanked by two SRB solid rocket boosters on each side, together generating about 2,800 tons of thrust.

Once the solid propellant of the SRBs was exhausted and separated, the shuttle still had to fly with the fuel tank attached until it reached orbit.

Each RS-25 engine could produce a thrust of 167 tons at sea level, but nuclear engines didn’t have this ability. Their advantage was in specific impulse, not thrust, and the FAA would definitely not grant takeoff permission to a space shuttle firing up nuclear engines on the ground, or else the public would storm Capitol Hill.

The nuclear-powered Endeavour would need to enter space as a payload, like the previous Union’s "Blizzard" spacecraft, rather than as part of the rocket. Therefore, the launch system also needed to be significantly changed.

This seemingly difficult problem didn’t stump the engineers. In fact, there were plenty of plans from the last century to convert the STS into a pure payload transporter, and they just needed to pick one and modify it.

The nuclear-powered version of Endeavour still lay on top of the fuel tank, fitted with four RS-25 engines, which, however, were mounted on the opposite side of the tank, facing the shuttle.

It was essentially a relocation of the shuttle’s four engines to the opposite side, maintaining the total thrust without reduction.

These four engines were installed within a triangular body of a circular cone, drawing fuel like the shuttle to power the engines, providing a combined thrust of 670 tons. The extra thrust was not only to compensate for the dead weight of the new structure but also to offset the loss of power due to the thrust vector angle.

The fuel tank, with one side weighing over a hundred tons and the other at most ten tons, obviously required the four RS-25s to have a larger angle of attack, and the entire assembly had to tilt after lift-off to align the intersection of the thrust from the two SRBs and four RS-25s with the overall center of gravity.

As a result, the shuttle was no longer "leaning back" as before but was "prone" like the H2, perched on top of the rocket and sent into space.

This scheme was very similar to the 1125K "Energy" rocket, capable of carrying over a hundred tons of payload on the side of the rocket. The original idea was to develop a giant rocket to replace the Saturn V based on the foundation of the STS.

With reduced difficulty and previous preliminary studies, it was quickly confirmed as the basic configuration and became the future launch method for nuclear-powered space shuttles.

What Boeing and NACA are now debating is whether to reuse the four engines on the side of the fuel tank.

The original purpose of the design was definitely reuse, as the triangular body equipped with four RS-25s was shaped that way to re-enter the atmosphere and bring back the extremely expensive, nearly 200 million US dollar quartet of hydrogen-oxygen engines.

Otherwise, why not just follow the SLS routine and place it at the bottom of the fuel tank, which would reduce the workload by more than 50% at once.

But the issue is the recovery method for the propulsion section. Boeing currently has two solutions:

The first is to optimize the triangular body into a central lifting body, acting as a transformed mini space shuttle, gliding with the engines for landing;

The second is without wheels, crashing into the sea, and directly rescued from the water during landing.

Each solution has its pros and cons, one being safer and the other being less troublesome, but both require a greater workload. Now, as Boeing continues to absorb various companies and nearly monopolize the industry, it has tasted the consequences. It’s a primary contractor for NACA and already has too many tasks. They need to reduce the workload.

Rockdain’s stance also adds to their dilemma. Each RS-25 costs over 50 million US dollars; four RS-25s indeed necessitate recovery.

However, Rockdain also mentioned they’ve developed a simplified version of the RS-25, a disposable "chicken blood" version, with the thrust increased to 200 tons (at sea level), and the specific impulse and thrust-to-weight ratio improved, all at a reduced price of just over 20 million US dollars. With the RS25E, three engines would be enough.

Do they take on more work to recover 200 million US dollar worth of engines or save some trouble and discard nearly 70 million US dollars’ worth each flight?

To reuse or not to reuse, that is the question.