Our Artemis program will return humans to the Moon by 2024. Artemis I, the first Artemis mission, will test all of the human rated systems in deep space — including the Orion spacecraft and Space Launch System rocket. This is its 26 day journey… in 30 seconds. Credit: NASA

The first test flight in 2020, Artemis 1, will carry an uncrewed Orion space capsule to the moon to test the performance of the integrated system. SLS also will carry 13 small satellites, each about the size of a shoebox, that will be deployed in deep space.

NASA’s Space Launch System (SLS) rocket delivers propulsion in stages to send NASA’s Orion spacecraft and heavy cargo to the Moon for the Artemis lunar missions. At liftoff, the core stage and twin solid rocket boosters fire to propel the rocket off the launch pad send it into orbit. Once in orbit, the upper stage provides the in-space propulsion to set the spacecraft on a precise trajectory. While the rocket’s core stage design will remain the same for each of the Artemis missions, the rocket’s upper stage is selected to meet various mission requirements and goals. For the first three Artemis missions, including the mission that will land the first woman and the next man on the Moon by 2024, SLS will utilize an interim cryogenic propulsion stage with one RL10 engine to send Orion to the Moon. Later missions with the evolved SLS Block 1B rocket configuration will use an exploration upper stage with larger fuel tanks and four RL10 engines to send a crewed Orion and large cargos to the Moon. 

NASA is working to land the first woman and next man on the Moon by 2024. SLS and Orion, along with the Gateway in orbit around Moon, are NASA’s backbone for deep space exploration. SLS is the only rocket that can send Orion, astronauts and supplies to the Moon in a single mission.

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eus update

After its debut was postponed and production plans suspended, NASA gave its OK in June to a set of design changes proposed by prime contractor Boeing for the Exploration Upper Stage (EUS). EUS was planned to become the upper stage for NASA’s Space Launch System (SLS) rocket on its second launch, but last year the space agency requested a study of possible changes after Congress decided to fly more SLS launches with its current interim upper stage.

Boeing provided NASA with choices to optimize the stage for lunar payloads at the end of 2018, but the future of the stage came into question at the beginning of this year. With the delay in its first launch, funding was first cut in half in the last fiscal year and then the White House proposed completely defunding it this year.

Shortly thereafter, the Artemis Program was started with the goal to land U.S. astronauts on the Moon by the end of 2024 and with its own funding needs, EUS is not a part of the White House’s lunar landing plans. Congress has been the main champion of development and application of the stage, including restoring funding to its previous level, and if the spending bill up for vote this week were to be enacted into law, it is possible that Critical Design Review (CDR) could occur during Fiscal Year 2020.

(Click on it, to see biger) The Exploration Upper Stage (EUS) is a liquid hydrogen, liquid oxygen stage using four Aerojet Rocketdyne RL-10C3 engines.  Credit NASA. 

Photo Caption: A recently released NASA infographic provides a couple of the updated measurables for the redesigned EUS. After resizing the stage’s propellant tanks and other elements (such as bottles for gaseous helium), the stage is less than a foot shorter and approximately a ton lighter when dry. Source: nasaspaceflight.com

The timetable for finishing development and flying the single EUS flight unit currently under contract is caught between competing priorities advanced by the White House and Congress.  When Vice President Pence announced the goal at the end of March of landing U.S. astronauts on the Moon by the end of 2024 that became NASA’s highest priority.

EUS plays no role in those plans, as SLS is only necessary for a single launch in support of the Artemis 3 mission that would accomplish the lunar landing goal within five years. Commercial launch vehicles will launch all the elements in the Artemis infrastructure including both required elements of the cislunar Gateway, all lunar Human Landing System (HLS) elements, and any required Gateway logistics supply spacecraft.

The final planned Artemis 3 launch would be an SLS Block 1 vehicle that uses an ICPS upper stage to send Orion and its lunar landing crew to dock with the Gateway where the Artemis HLS infrastructure will already be pre-assembled. Without a clear role for EUS in their plans for Gateway or Artemis, the White House proposed zeroing out funds for it beginning in the current fiscal year that began on October 1.

The interim cryogenic propulsion stage (ICPS) for the first flight of NASA's Space Launch System rocket. Credit: United Launch Alliance (ULA)

NASA Administrator Jim Bridenstine announced additional changes are being considered which would overhaul the early manifest of Exploration flights. The Administration’s new budget proposes defunding the Exploration Upper Stage (EUS) and related projects beginning with Fiscal Year 2020 that starts on October 1.

In subsequent Senate testimony, Administrator Bridenstine confirmed that SLS would not be able to meet the agency’s previous June, 2020, launch date commitment for Exploration Mission-1 (EM-1) and that NASA had started a study to look at commercial launch options to try to save the schedule. 

Under the new proposals, the next two Exploration missions for NASA’s Orion crewed spacecraft would be replaced by three missions to get back on schedule.  In addition to the commercially launched EM-1, the other new missions would introduce a new lunar payload and skip the test flight for the first crewed mission in favor of an operational Orion mission to fly to the new payload.

The FY 2020 request calls for all Lunar Gateway payloads previously under consideration to fly “co-manifested” on SLS with Orion in the Block 1B Crew configuration to now use commercial launch services.

The critical path to the first launch for SLS is its new piece, the Core Stage. NASA’s Office of Inspector General detailed cost and schedule overruns for the SLS Core Stage and the reasons behind them in a report published in October.

In announcing the delay, Administrator Bridenstine also spoke about a commercial launch alternative to hold the EM-1 schedule. “Certainly, there are opportunities to utilize commercial capabilities to put the Orion crew capsule and the European Service Module in orbit around the Moon by June of 2020, which was our originally stated objective, and I have tasked the agency to look into how we might accomplish that objective,” he said in his Senate testimony.

The Administrator spoke about one possible alternate mission profile during the March 13 Senate hearing, which would be a two-launch, Earth Orbit Rendezvous (EOR) mission similar to ones considered during the Constellation Program that was cancelled in 2010.

“Here’s what we can do potentially — we’re starting that [study] process now. We could use two heavy-lift rockets to put the Orion crew capsule and the European Service Module in orbit around the Earth, launch a second heavy-lift rocket to put an upper stage in orbit around the Earth and then dock those two together to throw around the Moon the Orion crew capsule with the European Service Module,” he explained.

NASA’s powerful Space Launch System rocket and NASA’s Orion spacecraft are making progress to the pad. Over the course of their development, the rocket and spacecraft have moved from design and manufacturing to testing and assembly and integration. Some of the hardware has even been delivered to the launch pad at NASA’s Kennedy Space Center in Florida. Along with the Gateway in lunar orbit and a new human landing system, SLS and Orion create the backbone for the agency’s Artemis missions to the Moon that will land astronauts on the lunar surface by 2024 From the top to the bottom, you can take a look at the completed flight hardware for SLS and Orion for the first flight, Artemis I, in this latest video. Credit: NASA's Marshall Space Flight Center

 The nasa's space launch system - SLS

The SLS is designed for deep space missions. It will send the Orion spacecraft or other cargo to the Moon, which is nearly 1,000 times farther than where the space station resides in low-Earth orbit, at about 400 kilometers. The rocket have the power to help the Orion spacecraft to reach the speed of at least 24,500 mph needed to break out of low-Earth orbit gravity and travel to the Moon. 

The Space Launch System (SLS) Evolution. Credit: NASA

Every SLS configuration uses the core stage with four RS-25 engines. The first SLS vehicle, called Block 1, can send more than 26 metric tons (t) or 57,000 pounds (lbs.) to orbits beyond the Moon. It will be powered by twin five-segment solid rocket boosters and four RS-25 liquid propellant engines. After reaching the space, the Interim Cryogenic Propulsion Stage (ICPS) will sends the Orion spacecraft to the Moon.

The Interim Cryogenic Propulsion Stage (ICPS) for the first flight of NASA's Space Launch System rocket. Credit: United Launch Alliance (ULA)


The Aerojet Rocketdyne RS-25, or Space Shuttle Main Engine (SSME), is a liquid-fuel cryogenic rocket engine that was used on NASA's Space Shuttle and is planned to be used on its successor, the Space Launch System (SLS). The American engine RS-25 burns cryogenic liquid hydrogen and liquid oxygen (LH2/LOX) propellants producing 1,859 kN (418,000 lbf) of thrust at liftoff for each one used in the Shuttle. Although the RS-25 can trace its heritage back to the 1960s, concerted development of the engine began in the 1970s, with the first flight occurring on April 12, 1981, with the STS-1. Learn More

RS-25 engine No. 2059 arrives at the A-1 Test Stand at Stennis Space Center on Nov. 4, 2015.

The RS-25E, built by Aerojet Rocketdyne, is an expendable version of the RS-25, also called the Space Shuttle Main Engine (SSME). Four RS-25E engines will be used for each core stage of NASA’s upcoming SLS. Actually, sixteen of these engines are available for the SLS missions, which begin in late 2018. The RS-25E will be used on subsequent SLS vehicles.

Crews delivered the last of four RS-25 engines for Artemis 1, the first flight of NASA’s Space Launch System (SLS) rocket and the Orion spacecraft, from NASA’s Stennis Space Center near Bay St. Louis, Mississippi, to NASA’s Michoud Assembly Facility in New Orleans Thursday, June 27, 2019.

On Nov. 6, engineers and technicians attached the last of four RS-25 engines. All four RS-25 engines were structurally mated to the core stage for NASA’s Space Launch System (SLS) rocket for Artemis I, the first mission of SLS and NASA’s Orion spacecraft. To complete the assembly of the rocket stage, engineers and technicians are now integrating the propulsion and electrical systems within the structure.
Each RS-25E will burn a Liquid Oxygen-Liquid Hydrogen (LOX-LH2) propellant mixture to produce about 2,277 kN (512,000 lbf) of thrust. Though the original SSMEs were expensive, NASA is working with Aerojet Rocketdyne to develop manufacturing methods to increase performance while at the same time reduce the per-unit cost.
The RS-27A is the engine used to power the core stage of the Delta II. Also developed by Aerojet Rocketdyne, the RS-27A burns LOX and kerosene, producing a thrust of about 890 kN (200,100 lbf).

 solid rocket BOOSTER or srb

Together, the SLS twin boosters provide more than 75 percent of the total SLS thrust at launch. The boosters are manufactured by Orbital ATK in Utah. The major physical difference between the shuttle and SLS boosters is the addition of a fifth propellant segment to the four-segment shuttle booster, allowing NASA’s new launcher to lift more weight than the shuttle. Additionally, the SLS booster will be optimized for a single use, while the shuttle booster was designed to be reused. Though based on the shuttle booster, the SLS booster benefits from several design, process, and testing improvements for greaterperformance, safety, and affordability.

Boosters are 177 feet Long, 12 feet Diameter, Weight 1.6 million pounds each, use polybutadiene acrylonitrile (PBAN) as propellant, and give 3.6 million pounds each of Thrust... for a Operational time of 126 seconds. Credit: NASA

Each booster is mated to the SLS core stage by braces on the forward and aft booster segments. On the launch pad, the booster carries the entire weight of the fueled SLS launch vehicle. After launch, the boosters operate for about two minutes before separating from the core stage.

Images credit: ATK

A test version of the booster for NASA's new rocket, the Space Launch System, will fire up for the second of two qualification ground tests at 10:05 a.m. EDT (8:05 a.m. MDT) Tuesday, June 28 at prime contractor Orbital ATK's test facility in Promontory, Utah.

Credit: Cislunar and Gateway Overview, William Gerstenmaier, HEOMD AA / Jason Crusan, AES Director and Gateway Formulation Lead, NASA HQ

The Exploration Mission 1 (EM-1) is an uncrewed mission to test Orion’s capabilities in deep space. EM-1 is the first flight of the European Service Module (ESM) and also Orion’s first flight on the new SLS. During the mission, the Crew Module guidance navigation and control system will command the ESM propulsion system to place the spacecraft into a Distant Retrograde Orbit around the moon. The nominal mission duration is 25 days, but will be adjusted between 21 and 43 days in order to ensure a landing under daylight conditions.

Credit: Cislunar and Gateway Overview, William Gerstenmaier, HEOMD AA / Jason Crusan, AES Director and Gateway Formulation Lead, NASA HQ

The Exploration Mission 2 (EM-2) is the first crewed mission for the Orion spacecraft. This mission will be historical for the Europe because the European Service Module 2 (ESM-2) will be the first European spacecraft to be part of a human transportation system beyond the low Earth orbit. After the launch, the SLS and the Interim Cryogenic Propulsion Stage (ICPS) will place the Orion spacecraft into a high Earth orbit, where the astronauts will remain for 24 hours to check out the spacecraft’s systems. When Mission Control gives the approval to initiate trans-lunar injection, the ESM-2’s Orion Orbital Manoeuvring System (OMS) will fire and send the spacecraft on a free-return trajectory out toward and around the Moon. The ESM-2’s Auxiliary (AUX) thrusters will be used to make any needed trajectory corrections along the way.
NASA and Lockheed Martin will conduct the EM-2 Critical Design Review (CDR) in late 2018. In 2015, NASA and LM completed the Orion CDR evaluating the common aspects of the spacecraft for EM-1 and the spacecraft for EM-2. The EM-2 CDR will confirm that the EM-2 unique systems also meet the necessary requirements and that the upgrades to the ESM design from ESM-1 to ESM-2 are appropriately integrated into the overall spacecraft design.



NASA’s Space Launch System Block 1 70-metric-ton. This artist illustration identifies the major parts of NASA’s Space Launch System.

Technical Specifications. Credit: Boeing

Click on it to see bigger

NASA's new deep space rocket, the Space Launch System (SLS), will launch missions powered by four RS-25 engines, reliable engines used for more than 135 space shuttle missions. The engines have been upgraded with new controllers and other features for SLS. Each engine has a unique number that allows engineers to track its flight history.

the rl-10

The RL10 is a liquid-fuel cryogenic rocket engine used on the Centaur, S-IV and Delta Cryogenic Second Stage (DCSS) upper stages. Built again in the United State by Pratt & Whitney Rocketdyne, the RL10 burns cryogenic LH2/LOX propellants, with each engine producing 64.7 to 110 kN (14,545–24,729 lbf) of thrust in vacuum depending on the version in use.

TheCentaur upper stage lifted up to put on the first stage of the Atlas V

The RL10 was the first liquid hydrogen rocket engine to be built in the USA by Marshall Space Flight Center and Pratt & Whitney in 1950s - the first flight occurring in 1961. After that, several versions have been flown, as theRL10A-4-2 and the RL10B-2, while still being produced and flown on the Atlas V and Delta IV.

The engine produces a specific impulse (Isp) of 373 to 470 s (3.66–4.61 km/s) in a vacuum and has a mass ranging from 131 to 317 kg (289–699 lb), depending of the version. Six RL10A-3 engines were used in the S-IV second stage of the Saturn I rocket, one or two RL10 engines are used in the Centaur upper stages of Atlas and Titan rockets and one RL10B-2 is used in the upper stage of Delta IV rockets.

RL10 test fire