Shulou(Shulou.com)11/24 Report--

NASA's giant rocket Space launch system (SLS) and Elon Musk's SpaceX starship will launch humans into space in the next few decades, including landing on the moon and even Mars. Both systems are likely to try to launch next month, ushering in a new era of space exploration. So what is the difference between them and what are their goals?

1. Height, weight and thrust SLS and starships are the most powerful rockets in the world. Among them, starships seem to have greater advantages:

Starships can generate 1600 million pounds (7257 tons) of thrust, while SLS can generate 8.8 million pounds (3992 tons).

SLS's Block 1 (launch system I) is 322ft tall and the starship is 394ft tall, with the ship itself 164ft tall and its booster 230ft high.

When filled with propellant, the starship weighs 1100 million pounds (5 million kilograms). By comparison, SLS weighs 5.5 million pounds (2.5 million kilograms).

Starships do not use solid fuel and use liquid oxygen and methane as propellants, while SLS uses liquid oxygen, liquid hydrogen and solid fuel; in addition, starships are powered by 32 Raptor engines and the SLS core class uses four RS-25 engines.

two。 The construction cost and time span of SLS coincided with NASA's return to the moon program Artemis, but the design of the launch vehicle made its debut in 2011. Eight years ago, SLS entered the stage of formal development.

Many of the delays since then have been caused by problems with SLS itself, and the Artemis project has been plagued by problems with the development of spacesuits and manned lander systems that will send astronauts to the lunar surface.

To reduce cost and development time, NASA has been upgrading the proven hardware of the space shuttle and other exploration projects, using cutting-edge tools and manufacturing technology. Some parts of SLS are new, while others are upgraded, such as adding functions needed to meet the needs of modern space exploration missions. The entire Artemis project costs about $23 billion and cannot be reused.

Musk starship booster is the result of years of research and development, has been used in 2009 decommissioned Falcon 1 rocket, Falcon 9 rocket, Falcon heavy rocket and now super heavy rocket.

Therefore, in terms of development and manufacturing costs, it is difficult to accurately compare SLS with starships. But in the case of starships alone, it is estimated that it has spent about $216 million on SpaceX.

The idea of SpaceX super-heavy rockets dates back to November 2005, when Musk first talked about his vision of building giant rockets.

3. Starship and SLS working principle SLS is powered by a core stage and a temporary cryogenic propulsion stage, flanked by two solid rocket boosters. The solid rocket booster contains the propellant polybutadiene acrylonitrile, which provides more than 75% of flight thrust in the first two minutes of flight. At the same time, the core stage stores about 2 million litres of supercooled liquid hydrogen and liquid oxygen to provide fuel for the RS-25 engine.

Unlike the SLS, starships are reusable launch systems, so their flight costs may be 200 times cheaper than most rockets. When ready to land on the ground, the starship will initially re-enter the atmosphere at an angle of 60 degrees and then "dive" to the ground in a horizontal position.

This return mode uses the atmosphere to slow the descent of the aircraft, but the disadvantage is that it is not stable. It is for this reason that starships install four steel landing flaps at the front and rear to control their descending posture, similar to the way skydivers use their arms and legs to control free fall.

When the starship approaches the ground, it will flip back to a vertical attitude and activate the Raptor engine to control a safe landing.

In November 2019, Musk claimed that the cost per launch of a starship could be as little as $2 million due to increased efficiency due to the reuse of rockets. By contrast, the cost per launch of the SLS is estimated to be as high as $4.1 billion.

4. The manned capsule SLS carries a capsule called Orion that can hold four astronauts. Although NASA is scheduled to test-launch the SLS for the first time in November, it will be the second launch of the Orion capsule. Orion made its first test flight in December 2014, when it went into space on a ULA Delta IV heavy rocket.

When launched in November, Orion will not carry any crew, but will carry dummies to and from the moon. These designs are designed to replicate human weight and allow scientists and engineers to understand the flight performance of the capsule without putting humans at risk.

From launch to return, Orion will be connected to the 3-meter-long European Service Module (ESM), which provides air, water, electricity and power.

If the plan goes well, Artemis II will launch a manned flight around the moon in 2024, while Artemis III will send humans back to the lunar surface in 2025. At that time, SLS, Orion and starships will work together. When Orion reaches lunar orbit, it will dock with the lander that the starship acts as.

In 2021, NASA awarded SpaceX a $2.89 billion contract to develop a starship into a lander capable of sending astronauts to the lunar surface by 2030. Eventually, NASA hopes to dock Orion and the lander with the lunar orbiting space station for more complex space missions.

On the other hand, starships will eventually be able to carry as many as 100 people to Mars. For long trips to and from Mars (one-way trips can take up to nine months), Musk wants to install about 40 cabins in the payload area near the front of his superiors.

Musk once said: "if you really want people to squeeze in, each cabin should hold five to six people. But I think in most cases, we expect two or three people in each cabin, so each flight to Mars can carry about 100 people."

As for the rest of the payload, the maximum payload of the starship in low-Earth orbit is 100 to 150 tons, and that of the lunar orbit is 100 tons, while the SLS is 95 tons and 27 tons respectively. Although the starship is temporarily in the lead, the SLS payload capacity is expected to increase as the design is updated.

5.SLS and Starship launch Starship is expected to be launched from an interstellar base in Texas near the town of Bokachica. However, SpaceX first needs to obtain a launch license from the Federal Aviation Administration (FAA) before launching.

Musk has previously said that starships can lift off from launch Pad 39A at Kennedy Space Center in Florida, which is currently used to launch SpaceX Falcon rockets. It is next to launch pad 39B, from where SLS will lift off.

Both launch vehicles have been plagued by a series of delays. Musk recently said he thought the super-heavy rocket should be able to launch this month. Asked when the starship would make its first orbital flight, Musk posted: "it may be the end of October, but November is also very likely."

SpaceX had planned to put the starship into orbit in January 2022, but was forced to postpone the plan after FAA conducted an environmental assessment of its Texas launch site.

The Artemis I mission was scheduled to launch at the end of August to launch the unmanned Orion capsule into space and begin orbiting the moon. But since then, with engine failures, fuel leaks and, more recently, hurricanes, SLS launches have had to be delayed again and again. NASA has said it plans to conduct a launch attempt between November 12 and 27.

6.SLS and starship have different goals. Technically speaking, both rockets are designed to send humans to Mars. But SLS will first pay more attention to the moon, including helping humans return to the lunar surface, building a space station in lunar orbit, and establishing a permanent human base on the moon.

Starships will also contribute in the process, and Musk has promised to travel around the moon for Japanese billionaire Maezawa in 2023. Obviously, starships can also be used for space tourism.

However, Musk's main vision for starships is to land on Mars, and he even hopes to build cities on the red planet. That sounds ambitious, but Musk's long-term goal for starships is that it could send people farther away in the solar system, including gaseous giants like Jupiter.

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