On September 3, 2022, at Cape Canaveral, they will try again to launch the Space Launch System (SLS) rocket with the Orion spacecraft. Everyone’s attention is riveted to this launch, because along with SLS (for which this will be the first launch), a new program of flights to the Moon, which includes the landing of astronauts on the satellite, will also start. But even without this circumstance, the SLS is a remarkable project, take at least, that today it is the most powerful rocket built by mankind.
1. The Most Powerful Rocket in History
The SLS is indeed the most powerful operational missile right now. Its main purpose now is Artemis, NASA’s new lunar program. The Orion manned spacecraft has also been developed for it. Only SLS can put it into orbit, Orion is too heavy for all other existing carriers.
In the future, SLS will be used for missions to Mars, as well as to more distant places in the Solar system. Thus, the carrier is to be used to launch the Neptune Odyssey interplanetary station into orbit to study Neptune and its satellites, the device for landing on the surface of Jupiter’s moon Europa Lander, the Origins orbital telescope and others.
The advantage of SLS is that its modular design allows you to scale the power depending on the need. So, for the first launch within the framework of the Artemis 1 mission, the Block 1 configuration was chosen. It can put 95 metric tons into low Earth orbit, and 27 metric tons to the Moon. Block 1B is more powerful, its carrying capacity is already 105 metric tons for low Earth orbit and 42 for lunar orbit. Finally, the most powerful version of Block 2 can carry 130 metric tons and 46 metric tons, respectively. It is also capable of delivering cargo weighing up to 45 metric tons to a heliocentric orbit.
2. SLS Came About As a Result of Budget Cuts
The end of the Space Transportation System program, better known as the Space Shuttle, prompted NASA to look for a replacement. In addition, at the beginning of the 21st century, the idea of a new lunar mission and flights to Mars was updated. This is how the Constellation program was born, which provided for the creation of two launch vehicles: the heavy Ares I and the super-heavy Ares V. They were accompanied by the Orion manned spacecraft.
Alas, at the time, ideas and plans ran into budget cuts. In 2010, President Obama canceled it altogether, but Congress was against stopping developments in this direction. Therefore, a compromise decision was made: the Orion spacecraft remains, and instead of two launch vehicles, one super-heavy one is being developed. The latter became the SLS.
3. They Used the Achievements of the Space Shuttle
SLS even outwardly looks like a Space Shuttle for a reason. For it, the same scheme is used as for the Space Transport System, only modernized. The launch vehicle’s first stage is powered by four Aerojet Rocketdyne RS-25 liquid propellant rocket engines. They were also installed on shuttles (only the latter had three of them). The large orange tank contains fuel — liquid hydrogen (fuel) and liquid oxygen (oxidizer). For the first four launches, the SLS uses 16 engines left over from the shuttles. Aerojet Rocketdyne has upgraded them with better controllers and tighter insulation as they will be located very close to the solid boosters.
For subsequent launches, more advanced RS-25E will be used. They will provide stronger traction, additionally they will also be 30% cheaper to run.
Two advanced solid-propellant boosters are attached to the first stage. On the shuttles, they consisted of four segments, and on the SLS — of five: compared to the shuttles, their thrust increased by 25%. In addition to the segment, the boosters received new avionics and lightweight insulation. However, unlike the shuttles, after the launch of which the boosters were detached and splashed down by parachutes, on the SLS they will be disposable.
4. The Project is Very Expensive
From 2011 to 2021, NASA spent about $23 billion developing the SLS. And this even though, as mentioned above, the developments of the shuttle program and the failed Ares-5 were used for the new rocket. In addition, these costs include only the creation of the rocket itself, but not the Orion spacecraft and its upper stage (for which the SLS was specially developed).
The cost of one rocket launch is difficult to pinpoint. NASA does not provide such information, and it is highly dependent on carrier and payload configuration. So, at least the first four launches as part of the Artemis mission will cost the US budget $4.1 billion each. Of these, 2.2 billion is for the SLS rocket itself, 1 billion for the Orion spacecraft, 300 million for the European Space Agency for a service block for the ship being built by Airbus, and 568 million for ground systems. And this is much more than NASA expected — five years ago, the cost of one launch was planned in the region of two billion.
5. SLS Has a Competitor
SpaceX Starship is the main competitor of SLS. It is being developed for the same purposes, and NASA signed a contract with the Musk company. The main competitive disadvantage of SLS is disposability. This makes the $4.1 billion launch price too expensive. SpaceX is making the Starship reusable and promising it will be able to launch up to 150 tons into low Earth orbit for less than $10 million per launch.