Angara-1.2 rocket variant
The Angara-1 will be the lightest variant in the Angara family of launch vehicles. Several variations of Angara-1 had been considered during its development, even though only one "flavor" is expected to reach an operational status.
Angara-1.2 launcher circa 2013. Copyright © 2013 Anatoly Zak
A new player in a crowded field
The flight testing of the new-generation rocket family began with the light-weight Angara-1.2PP launcher. In addition to paving the way for a much larger workhorse vehicle, Angara-1 was being positioned as the main light-weight delivery system for compact satellites of the Russian Ministry of Defense, the domestic civilian space agency Roskosmos and for international customers around the world.
In all three roles, Angara-1 was expected to replace space launchers converted from ballistic missiles, such as Rockot and Dnepr. Unlike its Cold-War predecessors, Angara would use much less toxic propellants in most of its propulsion systems and use newer hardware built entirely inside Russia. However, at the same time, Angara-1 enters a crowded launch market on the heels of other new players in the same "weight category" at home and abroad, such as the European Vega and the Russian Soyuz-2-1v rockets. In August 2014, Russian space officials said that Angara and Soyuz-2-1v woud replace Rockot after 2016.
First contract announced
On Aug. 1, 2016, GKNPTs Khrunichev announced the first foreign commercial passenger for the Angara-1 rocket. The South-Korean Kompsat-6 remote-sensing satellite (a.k.a. Arirang) was booked for a ride from Plesetsk around 2020. Equipped with a Synthetic Aperture Radar, SAR, the 1.7 ton spacecraft should be inserted into the Sun-synchronous orbit. By the beginning of 2020, the launch of Kompsat-6 was postponed until the end of 2021.
The URM-1 standard module will serve as the first-stage booster for all versions of the Angara rocket. Angara-1 would feature one URM-1, Angara-3 would be made of three URMs and Angara-5 would sport five URMs. Finally, Angara-7, if ever approved for development, could feature six URM-1 boosters.
All URM modules will feature a liquid propellant stage equipped with the RD-191 engine and burning kerosene fuel and and liquid oxygen as an oxidizer. The engine has the capability to gimbal in its suspension system in order to steer the rocket along the pitch and yaw axis. The roll of the vehicle will be controlled with two aerodynamic stabilizers and four thrusters installed in the tail of the rocket and fed by a hot gas generated in the main engine.
The tail section of the URM-1 module has an outlet with multiple interfaces for pneumatic and hydraulic lines of the launch complex.
The 149-ton Angara-1.1 rocket could deliver two tons of payload into a 200-kilometer orbit with an inclination 63 degrees from Plesetsk, however this configuration was likely to be abandoned, possibly, because it matched too closely the capabilities of the Soyuz-2-1v rocket, while requiring toxic propellants on its upper stage.
The Angara-1.1 version would use a regular URM-1 booster as its first stage and a second stage deriving from the existing Briz-KM stage, currently flying as part of the Rockot booster. It would carry around 5.2 tons of nitrogen tetroxide and unsymmetrical dimethyl hydrazine, UDMH, propellant. These propellant components do not require cryogenic operational conditions, but they are extremely toxic.
Like its base Briz stage, the second stage on Angara-1.1 would have a movable main engine capable of multiple firings and four small thrusters pods, allowing high-precision maneuvering and attitude control during an unpowered flight in orbit.
The two stages of Angara-1.1 are connected via an intermediate compartment, which carries four solid-propellant motors for the separation of the first stage. When the URM-1 finishes its work, it drops away along with the intermediate compartment. At that moment, the four solid motors fire in the direction opposite of flight to prevent a collision between the two objects. During the separation, the second stage slides along special guide rails on the inner walls of the intermediate compartment.
The payload fairing for the Angara-1.1 rocket could be borrowed practically unchanged from the Rockot booster.
From its original launch pad in Plesetsk, Angara could fly north or east to reach four types of orbits with inclinations of 63, 75, 85.8 and 93.4 degrees toward the Equator. The URM-1 first stage was designed to fire for 239.8 seconds and separate at an altitude of 118 kilometers. It would then fall either in Siberia or in the Arctic, depending on the targeted orbit. Around 20 seconds later, the payload fairing would split in two halves and fall not far from the first stage, some 2,860 kilometers from the launch site. The Briz-KM second stage would then take over, firing until the 946th second in flight.
To reach the low circular orbit not exceeding 300 kilometers, Angara-1 could use a single firing of the Briz-KM second stage. However to reach higher orbits, the Briz-KM would first fire to enter an elliptical orbit with an apogee at the altitude of the desired final orbit. It would then climb up without thrust for around 45 minutes and restart its engine in the apogee as high as 1,500 kilometers to make the orbit circular, before releasing its payload.
The original version of the Angara-1.2 rocket was expected to have a liftoff mass of 171-tons and the capability to put 3.7 tons of cargo into the low Earth's orbit from Plesetsk.
During the flight, the launch vehicle would be kept on course with the help of a gyroscopic system and an onboard computer derived from the Biser-6 flight control system both developed at the NPTs AP design center in Moscow. The Orbita telemetry system would process the flight data.
According to the original plans, the Angara-1.2 version would combine the standard URM-1 module with a diameter of 2.9 meters as its first stage and the URM-2 module as its second stage. The URM-2 module with a diameter of 3.6 meters derived from the already existing Block I stage, which had been developed for the Soyuz-2 rocket. As a result, the Angara-1.2's top stage would have wider diameter than its lower rocket module.
However around 2009, it was decided to use this configuration only for the maiden test flight of Angara-1 in order to certify the URM-1 and URM-2 boosters, before they both fly on a much larger Angara-5 rocket.
In the meantime, an operational variant of Angara-1.2 was redesigned to have the same diameter of 2.9 meters on its both stages. As a result, a new thinner second stage would be developed for an operational Angara-1.2. In the meantime, the original URM-2 stage with a diameter of 3.6 meters will fly on Angara-5 and Angara-3 rockets. Obviously, this will reduce the standardization across the Angara family and likely increase its cost. However both stages could still be propelled by the RD-0124A engine.
In October 2014, Chief Designer KB Salyut Yuri Bakhvalov said that the first Angara-1.2 would be launched in 2016.
In August 2014, the head of GKNPTs Khrunichev Vladimir Nesterov said that the light-weight version of the Angara rocket would be equipped with an "aggregate module," which will be installed on top of the second stage and act as a space tug, completing the job of inserting satellites into their final orbits. The new third stage was developed based on the company's existing propulsion system and would fly for the first time in 2015 or 2016, after the first launch of the Angara-5 rocket, Nesterov said at the time.
As of 2017, the Aggregate Module, apparently designated 2A2S, was to be equipped with four 11D458 engines with a thrust of 40 kilograms and 14 smaller 17D58E engines with a thrust of 1.3 kilograms, all developed by the NIIMash propulsion center.
Aggregate module undergoes testing
On Nov. 17, 2017, GKNPTs Khrunichev announced that the propulsion system for the aggregate module of the Angara-1.2 rocket had undergone a successful static firing at an engine test facility of the NITs RKP center in Peresvet, north of Moscow on November 13 of the same year. The live firing of the engine followed the successful thermal and vacuum testing of the aggregate module at the VK600/300 chamber also in Peresvet in November 2016, GKNPTs Khrunichev said.
Another sign of progress with the Angara-1.2 variant appeared in the footage from the Omsk production factory released by Roskosmos in the first half of 2019. It included views of the checkout and test facility, KIS, for integrated testing of the Angara-1.2. The construction of the site seemed to be fully completed, but the empty facility was yet to be outfitted with all its diagnostics equipment.
The checkout and test facility, KIS, for integrated testing of the Angara-1.2 rocket during construction circa 2019.
Known specs of the Angara-1.2 rocket (14A125):
Known specs of the first stage of the Angara rocket (ground test vehicle NZh 14A125 2A1S):
A scale models of the Angara-1.1 and Angara-1.2 launchers circa 2000. Copyright © 2001 Anatoly Zak
A scale model of the Angara-1.2 launcher circa 2007. Copyright © 2009 Anatoly Zak
A configuration of Angara-1.2 rocket shown as late as 2010. Copyright © 2010 Anatoly Zak
A scale model of the Angara-1.2 launcher displayed in 2011. Copyright © 2011 Anatoly Zak
A scale model of the Angara-1.2 launcher as of 2013. Copyright © 2013 Anatoly Zak
An aggregate module for the Angara-1.2 rocket during testing at NITs RKP around Nov. 13, 2017. Click to enlarge. Credit: GKNPTs Khrunichev