The first flight of Russia's new Angara launcher was postponed Friday after engineers discovered a technical problem in the final minutes of the countdown.

The Angara 1.2PP rocket on the launch pad at the Plesetsk Cosmodrome. Credit: Russian Ministry of Defense
 
With Russian President Vladimir Putin watching on video, officials decided to abort the countdown and resolve the problem before another launch attempt.

Russian officials did not disclose the issue that caused the delay, and Russia did not immediately announce a new launch date after Friday's canceled launch attempt.

Putin told military officials to "work without hurrying and chaos" to diagnose the problem and ready the rocket for another launch attempt, according to a report by the RIA Novosti news agency.

The 140-foot-tall Angara rocket was supposed to lift off from the Plesetsk Cosmodrome, a military-run facility about 500 miles north of Moscow, at 1115 GMT (7:15 a.m. EDT) Friday on a suborbital test flight. The rocket's second stage and a dummy payload were expected to impact the Kamchatka peninsula in Russia's Far East more than 21 minutes after launch.

Technicians on Wednesday transferred the rocket to Site 35 at Plesetsk, a launch pad originally designed for the Ukrainian Zenit rocket and modified to host the Angara launcher.

Officials intend for the Angara rocket to be the future workhorse of Russia's space program, replacing a fleet of launch vehicles -- including the Rockot and Proton boosters -- to lift small and large payloads into a range of orbits.

The Angara rocket comes in several configurations, with the light-class Angara 1 capable of putting up to 3.8 metric tons, or nearly 8,400 pounds, into a 200-kilometer (124-mile) orbit tilted at an angle of 63 degrees to the equator, according to the Khrunichev State Research and Production Space Center, lead contractor for the Angara launcher.

Russia started work on the Angara rocket in 1992. After Khrunichev won the contract to design and build Angara, the Russian government stated the rocket should begin operations by 2005.

But financial woes in Russia slowed the rocket program, which has cost $2.9 billion to date, according to the Itar-Nass news agency.

The Angara rocket's maiden flight will use a special configuration named the Angara 1.2PP, testing the Angara's planned standard first and second stages in a shakedown flight before Russia puts a costly military or commercial payload on a future launch.

The Angara rocket family. Credit: Khrunichev
 
The Angara 1.2PP's first stage is powered by an RD-191 engine produced by NPO Energomash of Khimki, Russia, near Moscow. Engineers derived the single-chamber RD-191 engine from the four-nozzle RD-171 and dual-chamber RD-180 engines flying on the Zenit and Atlas 5 launchers.

Fueled by a mix of kerosene and liquid oxygen propellants, the RD-191 engine generates approximately 432,000 pounds of thrust at sea level, according to Energomash's website.

The second stage on the Angara rocket's maiden flight has a kerosene-fueled RD-0124A engine with 66,000 pounds of thrust, a new version of the engine previously flown on Russia's Soyuz 2-1b booster.

According to the Interfax news service, the Angara 1.2PP rocket's RD-191 first stage is programmed to fire for 3 minutes, 42 seconds on an easterly trajectory from the Plesetsk launch base. The second stage's RD-0124A engine will ignite as the first stage is jettisoned, then the rocket will release its payload fairing at 3 minutes, 52 seconds after liftoff.

The first stage and fairing are expected to fall in the Barents Sea, according to Khrunichev.

The second stage engine will switch off 8 minutes, 11 seconds into the mission before the rocket and its instrumented payload crash in Russia's Far East.

The Angara burns cleaner fuel than the rockets it will replace, which consume toxic hydrazine and nitrogen tetroxide propellants.

Designers planned the Angara rocket family to use common components, a decision that officials expect will reduce the vehicle's development and operating costs.

The Angara first stage with an RD-191 engine is called Universal Rocket Module No. 1. The URM-1 stage and the Angara's second stage, named Universal Rocket Module No. 2, will be used on most versions of the Angara launcher.

Khrunichev supplied a URM-1 first stage for South Korea's Naro rocket. Only one of the three flights of the Naro rocket was successful, but Khrunichev says the Russian first stage performed as expected on all three launches.

The Angara 3 configuration, featuring three URM-1 first stages attached together, can lift 14.6 metric tons, or about 32,200 pounds, to a 200-kilometer orbit at an inclination of 63 degrees.

A bigger launcher, called the Angara 5, will use a cluster of five URM-1 rocket stages and a URM-2 second stage to boost a payload of up to 24.5 metric tons -- more than 54,000 pounds -- into the same 200-kilometer orbit, according to Khrunichev.

Artist's concept of an Angara 5 rocket on the launch pad. Credit: Khrunichev
 
Engineers can add optional upper stages -- either the Breeze M flown on Proton launchers or a more capable hydrogen-fueled engine -- to propel communications satellites into geostationary transfer orbit, the typical drop-off point for telecom payloads destined to operate in a ring 22,300 miles over the equator.

With the addition of the hydrogen-fueled third stage -- still under development in Russia -- the Angara 5 can place 7.5 metric tons in geostationary transfer orbit, exceeding the lift capacity of the workhorse Proton/Breeze M.

Khrunichev also has worked on a concept named the Angara 7 that could be used for deep space missions, but that version has no confirmed flights.

Khrunichev has developed two iterations of the Angara 1. A less powerful configuration called the Angara 1.1 can be topped with a Breeze KM second stage -- a smaller model of the Breeze M -- and the heftier Angara 1.2 uses a second stage borrowed from the Soyuz rocket.

The Soyuz-derived second stage for the Angara 1.2 has a smaller diameter and carries less propellant than the URM-2 second stage used on the Angara 1.2PP test flight and larger Angara rockets.

Operational flights of the Angara rocket are set to begin next year from Plesetsk and the Vostochny Cosmodrome under construction in Russia's Far East.

Russian officials said the heavy-lifting Angara 5 rocket is scheduled for a test flight from Plesetsk in December.

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