Rockets: the engines, stages and missions behind major launch vehicles

Rockets are launch vehicles: they carry payloads away from Earth and, in some cases, place them in orbit or send them beyond it. Understanding their performance requires looking beyond a single number. An engine may power a core stage, a solid booster may add thrust during liftoff, and an upper stage may serve a different purpose after the vehicle leaves the atmosphere. Payload capacity also depends on the stated destination: low Earth orbit and geostationary transfer orbit are not the same target.

The sources gathered here describe components and capabilities of several launch vehicles. They do not provide a complete, standardized comparison of payload mass, cost, reliability or launch rate. The figures therefore need to be read in context, not as entries in a straightforward contest.

SLS: NASA’s launch vehicle for lunar exploration

The Space Launch System (SLS) is a NASA heavy-lift rocket associated with the agency’s deep-space exploration plans. NASA says every SLS configuration uses a core stage with four RS-25 engines. For the first configuration, called Block 1, the agency lists a capacity of more than 27 metric tons (59,500 pounds) to orbits beyond the Moon. That figure applies to a particular destination and should not be treated as directly equivalent to capacities stated for Earth orbits.

SLS also uses large solid rocket boosters. NASA describes them as the largest and most powerful solid-propellant boosters ever built for flight. Each stands 17 stories tall and burns approximately six tons of propellant per second. The source adds that each booster generates more thrust than a comparison involving “14” four-engine units, but the available text does not clearly identify those units. That incomplete comparison cannot be interpreted precisely, so it is not expanded on here.

The Artemis I mission illustrates the role engines can play in a specific mission. NASA says the RL10 engine provided in-space propulsion that sent an uncrewed Orion spacecraft to the Moon. The agency says the RL10 is also set to reprise that role on the crewed lunar missions Artemis II and Artemis III. This describes a planned future role, not missions that have already been completed.

New Glenn: capacity figures depend on the orbit

NASA’s Launch Services Program rockets page describes New Glenn as powered by seven Blue Engine 4 (BE-4) engines. According to that information, it can carry more than 13 metric tons to geostationary transfer orbit and 45 metric tons to low Earth orbit. The same source says New Glenn is on NASA’s Launch Services II contract.

The two capacity figures do not conflict: they refer to different orbital destinations. The supplied information does not specify other details here, such as the exact vehicle configuration associated with each figure, and it does not establish particulars of any individual mission. Nor does the existence of a contract, by itself, show that a specific launch has taken place or that a particular payload has been assigned.

Ariane 6 and Ariane 5: two European configurations

The European Space Agency describes Ariane 6’s core stage as the rocket’s largest section, located at its base. It is 32 metres tall and 5.4 metres wide, with a mass of 23,000 kilograms without propellants. The stage is powered by the Vulcain 2.1 engine. The supplied description says that this engine burns liquid oxygen, but the extract does not include all details of the propulsion system. Those details cannot be safely reconstructed from that sentence alone.

A NASA fact sheet on Ariane 5 presents a different architecture: it describes a 2.5-stage vehicle with four propulsion units. At liftoff, its twin segmented solid motors provide more than 500 tonnes of thrust each, augmenting the central Vulcain engine in the core stage, which is listed at 110 tonnes of thrust and uses liquid oxygen and liquid hydrogen (LOX/LH2). The fact sheet also says Ariane 5 was upgraded to handle dual payloads of four to five tonnes. The extract does not clarify the precise conditions for that capacity, so the wording should be kept general.

What these figures can—and cannot—tell us

The figures describe different things: engine count, dimensions, mass without propellant, propellant consumption rate, thrust or payload capacity to a specified orbit. None, on its own, summarizes a rocket’s overall performance. Even two capacities expressed in tonnes can only be compared directly if they refer to equivalent destinations and conditions—information that is not supplied consistently in these excerpts.

It is also important to distinguish vehicles from their engines and missions. SLS is the launch vehicle; RS-25 and RL10 are engines cited in connection with different stages or functions. Artemis I, II and III are lunar missions that NASA’s information links to Orion and the use of RL10. For New Glenn, BE-4 is the engine designation in the source. Ariane 5 and Ariane 6 are different vehicles, and information about one does not automatically describe the other.

A cautious reading of launch technology

Taken together, these examples show that large rockets combine propulsion systems and stages to serve different objectives: from sending an uncrewed spacecraft to the Moon to carrying payloads to Earth or transfer orbits. The sources emphasize SLS’s connection to Artemis and exploration beyond the Moon; they give New Glenn capacity figures for two orbits; and they detail aspects of Ariane design and propulsion.

The available evidence is nevertheless partial. It does not provide a common table of launch conditions, comparable payload masses, costs or reliability results. The strongest conclusion is therefore not that one rocket is “better” than another, but that each capability must be tied to the engine, configuration and destination for which it was reported.

Sources: NASA SLS fact sheets; NASA Launch Services Program rockets; NASA Space Launch System; SLS solid rocket booster; ESA on Ariane 6 components; NASA Ariane 5 fact sheet.