Eclipse, previously known as Firefly Beta and the Medium Launch Vehicle (MLV), is a

two-stage A multistage rocket or step rocket is a launch vehicle that uses two or more rocket ''stages'', each of which contains its own engines and propellant. A ''tandem'' or ''serial'' stage is mounted on top of another stage; a ''parallel'' stage is ...

, partially reusable

medium-lift launch vehicle A medium-lift launch vehicle (MLV) is a rocket launch vehicle that is capable of lifting between by NASA classification or between by Russian classification of payload into low Earth orbit (LEO).50t payloads" An MLV is between a small-lift ...

being jointly developed by

Firefly Aerospace Firefly Aerospace, Inc. is an American private aerospace firm based in Cedar Park, Texas, that develops small- and medium-lift launch vehicles for commercial launches to orbit. The current company was formed when the assets of the former co ...

and

Northrop Grumman Northrop Grumman Corporation is an American multinational Aerospace manufacturer, aerospace and Arms industry, defense company. With 97,000 employees and an annual revenue in excess of $40 billion, it is one of the world's largest Arms industry ...

. Formally announced in 2022, the rocket is designed to be a successor to Northrop Grumman's

Antares Antares is the brightest star in the constellation of Scorpius. It has the Bayer designation α Scorpii, which is Latinisation of names, Latinised to Alpha Scorpii. Often referred to as "the heart of the scorpion", Antares is flanked by ...

launch vehicle, able to be partially reused and can launch 16,300 kg (35,900 lb) into

low Earth orbit A low Earth orbit (LEO) is an geocentric orbit, orbit around Earth with a orbital period, period of 128 minutes or less (making at least 11.25 orbits per day) and an orbital eccentricity, eccentricity less than 0.25. Most of the artificial object ...

. Currently, the maiden launch of Eclipse is slated for the second half of 2026.

History

Firefly Beta

Eclipse can be traced back to the late 2010s, following Firefly Space Systems' 2017 liquidation and reestablishment as

. It was originally conceptualized as Firefly Beta, following a naming scheme previously established by the

Firefly Alpha Firefly Alpha (Firefly α) is a two-stage orbital expendable small lift launch vehicle developed by the American company Firefly Aerospace to compete in the commercial small satellite launch market. Alpha is intended to provide launch o ...

small-lift launcher. Beta's initial design consisted of three Alpha cores strapped together in a fashion similar to

Delta IV Heavy The Delta IV Heavy (Delta 9250H) was an expendable heavy-lift launch vehicle, the largest type of the Delta IV family. It had the highest capacity of any operational launch vehicle in the world after the retirement of the Space Shuttle in 20 ...

Falcon Heavy Falcon Heavy is a super heavy-lift launch vehicle with partial reusability that can carry cargo into Earth orbit and beyond. It is designed, manufactured and launched by American aerospace company SpaceX. The rocket consists of a center core ...

. This triple core configuration would not last, as by 2020 Firefly announced a redesign that replaced it with a scaled up iteration of Alpha, having a 3.7 m (12 ft) stage diameter, a 4.7 m (15 ft) tall fairing, and utilizing five Reaver 2 engines for its first stage. Additionally, Beta would be capable of placing 8,000 kg (17,600 lb) into LEO and 5,800 kg (12,800 lb) into

Sun-synchronous orbit A Sun-synchronous orbit (SSO), also called a heliosynchronous orbit, is a nearly polar orbit around a planet, in which the satellite passes over any given point of the planet's surface at the same local mean solar time. More technically, it is ...

. In October 2021, it was planned that Beta would have its maiden launch in the second half of 2024. In October 2019, Firefly and

Aerojet Rocketdyne Aerojet Rocketdyne is a subsidiary of American Arms industry, defense company L3Harris that manufactures rocket, Hypersonic flight, hypersonic, and electric propulsive systems for space, defense, civil and commercial applications. Aerojet traces ...

announced they would form a partnership, detailing that Firefly would manufacture a lifter making use of the

AR1 AR1 may refer to * AR-1 (multiple rocket launcher) * Aerojet Rocketdyne AR1, a rocket engine * Alba AR1, an experimental racing car * Archaerhodopsin-1, a photoreceptor * Arkansas's 1st congressional district * Arkansas Highway 1 * ArmaLite AR- ...

engine. However, it is unknown if this partnership ever lasted beyond concepts and proposals.

Collaboration with Northrop Grumman

On August 8, 2022, Firefly and

announced a partnership where they would collaborate on the development of both Beta and

. Originally operated by Orbital Science Corporation (later

Orbital ATK Orbital ATK Inc. was an American aerospace manufacturer and defense industry company. It was formed in February 9, 2015 from the merger of Orbital Sciences Corporation and parts of Alliant Techsystems (ATK). Orbital ATK designed, built, and de ...

) before their 2018 acquisition by Northrop Grumman, Antares's first stage was Ukrainian manufactured and powered by two

Russia Russia, or the Russian Federation, is a country spanning Eastern Europe and North Asia. It is the list of countries and dependencies by area, largest country in the world, and extends across Time in Russia, eleven time zones, sharing Borders ...

n made

RD-181 The RD-191 () is a high-performance single-combustion chamber rocket engine, developed in Russia and sold by Roscosmos. It is derived from the RD-180 dual-combustion chamber engine, which itself was derived in turn from the four-chamber RD-170 ( ...

engines. This setup was jeopardized following the

Russian invasion of Ukraine On 24 February 2022, , starting the largest and deadliest war in Europe since World War II, in a major escalation of the Russo-Ukrainian War, conflict between the two countries which began in 2014. The fighting has caused hundreds of thou ...

back in February, and forced Northrop Grumman to look in other directions regarding the future of Antares. As part of the announcement, Beta was officially rechristened as the Medium Launch Vehicle (MLV), receiving another redesign and stating that a de-rated version of MLV's first stage would be used for the newly unveiled Antares 300-series. Additionally, MLV would be designed as a full-on successor to Antares, with the 300-series being flown for three Cygnus flights as a stopgap while MLV continues development. As such, the rocket would also be able to launch from Antares's launch site at

Wallops Island Wallops Island is a island in Accomack County, Virginia, part of the Virginia Barrier Islands that stretch along the eastern seaboard of the United States. It is just south of Chincoteague Island, a popular tourist destination. Wallops Isla ...

Virginia Virginia, officially the Commonwealth of Virginia, is a U.S. state, state in the Southeastern United States, Southeastern and Mid-Atlantic (United States), Mid-Atlantic regions of the United States between the East Coast of the United States ...

Renaming to Eclipse

In February 2024, Firefly announced that they would be expanding the size of their manufacturing facility in Briggs,

Texas Texas ( , ; or ) is the most populous U.S. state, state in the South Central United States, South Central region of the United States. It borders Louisiana to the east, Arkansas to the northeast, Oklahoma to the north, New Mexico to the we ...

to support the production of MLV and Antares 330. This expansion doubles the area of the complex from 8,550 m² (92,000 square feet) to 19,230 m² (207,000 square feet). Two months later, they reported that the development was progressing smoothly, with the rockets' Miranda engines beginning full production in June. In the summer of 2024, Firefly and Northrop Grumman made an announcement that MLV would pursuit a partially reusable configuration in a similar vein to the operations of

Falcon 9 Falcon 9 is a Reusable launch system#Partial reusable launch systems, partially reusable, two-stage-to-orbit, medium-lift launch vehicle designed and manufactured in the United States by SpaceX. The first Falcon 9 launch was on June 4, 2010, an ...

New Glenn New Glenn is a heavy-lift launch vehicle developed and operated by the American company Blue Origin. The rocket is designed to have a Reusable launch vehicle, partially reusable, two-stage design with a diameter of . The first stage is powered ...

, and

Neutron The neutron is a subatomic particle, symbol or , that has no electric charge, and a mass slightly greater than that of a proton. The Discovery of the neutron, neutron was discovered by James Chadwick in 1932, leading to the discovery of nucle ...

. They clarified that the first stage will be able to perform

return to launch site A launch vehicle is typically a rocket-powered vehicle designed to carry a payload (a crewed spacecraft or satellites) from Earth's surface or lower atmosphere to outer space. The most common form is the ballistic missile-shaped multistag ...

(RTLS) maneuvers and landings, hoping that the technology for doing so would be refined and put into full use by the sixth flight of the vehicle after its first several flights are made in an expendable configuration. On May 29, 2025, Firefly announced that they have received a

US$ The United States dollar (Currency symbol, symbol: Dollar sign, $; ISO 4217, currency code: USD) is the official currency of the United States and International use of the U.S. dollar, several other countries. The Coinage Act of 1792 introdu ...

50 million investment by Northrop Grumman in their joint development of the rocket. Additionally, the two companies officially renamed the Medium Launch Vehicle to Eclipse.

Design

Both stages of Eclipse will use

RP-1 RP-1 (Rocket Propellant-1 or Refined Petroleum-1) and similar fuels like RG-1 and T-1 are highly refined kerosene formulations used as rocket fuel. Liquid-fueled rockets that use RP-1 as fuel are known as kerolox rockets. In their engines, RP- ...

and

LOX Lox is a fillet of brined salmon, which may be smoked. Lox is frequently served on a bagel with cream cheese, and often garnished with tomato, onion, cucumber, and capers. Etymology The American English word ''lox'' is a borrowing of Yiddi ...

as propellant as and a carbon-fiber composite for its air-frame, iterating on a process similarly used in the construction and flight of Alpha. Together, the vehicle stands at 55.7 m (183 ft) in height and 4.32 m (14.2 ft) in diameter. Additionally, the fairings are 5.4 m (17.7 ft) in diameter and can be customized to suit a variety of payload sizes. The first stage will be powered by seven Miranda tap-off engines, being able to provide of thrust and has 305 seconds of

specific impulse Specific impulse (usually abbreviated ) is a measure of how efficiently a reaction mass engine, such as a rocket engine, rocket using propellant or a jet engine using fuel, generates thrust. In general, this is a ratio of the ''Impulse (physics), ...

(I_sp). This stage is designed to be reusable, though a de-rated and expendable version will be used as the first stage of the

Antares 330 Antares (), known during early development as Taurus II, is an American expendable medium-lift launch vehicle developed and built by Orbital Sciences Corporation (later Orbital ATK and Northrop Grumman) with financial support from NASA ...

. The second stage will be powered with a singular Vira vacuum engine, providing of thrust with an impulse of 328 seconds. This stage will be expended, and thus any Eclipse flight will have a new unit flown for each launch.

Operations

The maiden flight and other early launches of Eclipse will be made at Launch Pad 0A (LP-0A) from the

Mid-Atlantic Regional Spaceport The Mid-Atlantic Regional Spaceport (MARS) is a commercial space launch facility located at the southern tip of NASA's Wallops Flight Facility on Wallops Island in Virginia, just east of the Delmarva Peninsula and south of Chincoteague, Vi ...

(MARS) at the

Wallops Flight Facility Wallops Flight Facility (WFF) is a rocket launch site on Wallops Island on the Eastern Shore of Virginia, United States, just east of the Delmarva Peninsula and approximately north-northeast of Norfolk, VA, Norfolk. The facility is operated ...

in Virginia. LP-0A was originally built for use in the 1990s for the Conestoga launch vehicle, and has subsequently been used from 2013 to 2023 by the Antares 100 and 200 series. This is in part because of the ease in comparability with Antares 330 thanks to the similarity in first stage engine. Eclipse will additionally share the pad with Alpha for launches from Wallops, being able to interchange the architecture to support both vehicles. Eclipse will also be able to make

polar orbit A polar orbit is one in which a satellite passes above or nearly above both poles of the body being orbited (usually a planet such as the Earth, but possibly another body such as the Moon or Sun) on each revolution. It has an inclination of abo ...

al launches from Space Launch Complex 2 West (SLC-2W) at

Vandenberg Space Force Base Vandenberg Space Force Base , previously Vandenberg Air Force Base, is a United States Space Force Base in Santa Barbara County, California. Established in 1941, Vandenberg Space Force Base is a space launch base, launching spacecraft from the ...

California California () is a U.S. state, state in the Western United States that lies on the West Coast of the United States, Pacific Coast. It borders Oregon to the north, Nevada and Arizona to the east, and shares Mexico–United States border, an ...

. Historically a

Thor Thor (from ) is a prominent list of thunder gods, god in Germanic paganism. In Norse mythology, he is a hammer-wielding æsir, god associated with lightning, thunder, storms, sacred trees and groves in Germanic paganism and mythology, sacred g ...

and

Delta Delta commonly refers to: * Delta (letter) (Δ or δ), the fourth letter of the Greek alphabet * D (NATO phonetic alphabet: "Delta"), the fourth letter in the Latin alphabet * River delta, at a river mouth * Delta Air Lines, a major US carrier ...

pad for the Western Range, it originally made its way into Firefly's hands following the

Delta II Delta II was an expendable launch system, originally designed and built by McDonnell Douglas, and sometimes known as the Thorad Delta 1. Delta II was part of the Delta rocket family, derived directly from the Delta 3000, and entered service in ...

's retirement in 2018 and is currently being used to launch Alpha. Similarly to LP-0A, SLC-2W will also be configurable to launch both Alpha and Eclipse. Firefly and Northrop Grumman additionally plan to supplement LP-0A's prograde launches with the use of Space Launch Complex 20 (SLC-20) at

Cape Canaveral Space Force Station Cape Canaveral Space Force Station (CCSFS) is an installation of the United States Space Force's Space Launch Delta 45, located on Cape Canaveral in Brevard County, Florida. Headquartered at the nearby Patrick Space Force Base, the sta ...

Florida Florida ( ; ) is a U.S. state, state in the Southeastern United States, Southeastern region of the United States. It borders the Gulf of Mexico to the west, Alabama to the northwest, Georgia (U.S. state), Georgia to the north, the Atlantic ...

. SLC-20 is located at the very north of Missile Row, previously used by the

Titan I The Martin Marietta SM-68A/HGM-25A Titan I was the United States' first multistage intercontinental ballistic missile (ICBM), in use from 1959 until 1962. Though the SM-68A was operational for only three years, it spawned numerous follow-on mode ...

and

Titan IIIA The Titan IIIA or Titan 3A was an American expendable launch system, launched four times in 1964 and 1965, to test the Transtage upper stage which was intended for use on the larger Titan IIIC. The Transtage was mounted atop two core stages deriv ...

in the 1960s as well as various

sounding rocket A sounding rocket or rocketsonde, sometimes called a research rocket or a suborbital rocket, is an instrument-carrying rocket designed to take measurements and perform scientific experiments during its sub-orbital flight. The rockets are often ...

s in the 1990s. Firefly first gained control of the pad in 2019, following the

United States Air Force The United States Air Force (USAF) is the Air force, air service branch of the United States Department of Defense. It is one of the six United States Armed Forces and one of the eight uniformed services of the United States. Tracing its ori ...

making an expansion of

Eastern Range The Eastern Range (ER) is an American rocket range (Spaceport) that supports missile and rocket launches from the two major List of rocket launch sites, launch heads located at Cape Canaveral Space Force Station and the Kennedy Space Center ( ...

launch activities in the wake of the

NewSpace Private spaceflight is any spaceflight development that is not conducted by a government agency, such as NASA or ESA. During the early decades of the Space Age, the government space agencies of the Soviet Union and United States pione ...

boom. Firefly has declared intentions to construct an assembly facility at

Cape Canaveral Cape Canaveral () is a cape (geography), cape in Brevard County, Florida, in the United States, near the center of the state's Atlantic Ocean, Atlantic coast. Officially Cape Kennedy from 1963 to 1973, it lies east of Merritt Island, separated ...

; however, they have acknowledged in 2024 that they are prioritizing development at LP-0A first, though they reinforced their commitment to the SLC-20 lease in the same statement.

References

External links

Official Firefly page

Official Northrop Grumman page
{{Orbital launch systems Firefly Aerospace Northrop Grumman Northrop Grumman space launch vehicles Reusable launch systems Space launch vehicles of the United States Proposed space launch vehicles