The Russian Federal Space Agency, Roscosmos, launched the Progress MS-05/66P resupply mission on Wednesday morning aboard the final Soyuz-U rocket in history. Liftoff from pad 1/5 at the Baikonur Cosmodrome began a mission that concluded with an orbital rendezvous and docking with the Station on Friday.

Progress MS-04 investigation wrap up:

Following confirmation of the most probable cause of the Progress MS-04 launch failure on 1 December 2016, Roscosmos ordered a complete third stage engine replacement on the last remaining Soyuz-U carrier rocket, which will be used to launch Progress MS-05 to the International Space Station.

The engine replacement is also being carried out on the third stage of the Soyuz-FG rocket, which is used to launch the crewed Soyuz missions to the Station.

It is understood that this engine replacement was made with an 11D55 (RD-0110) engine built in 2016, instead of the previously installed 11D55 engine that was produced in 2014 with the engine that failed on MS-04’s launch.

There is confidence within Roscosmos that the newly installed, 2016-built engine does not suffer from the same quality assurance issues that plagued the MS-04 third stage engine.

The inquiry into December’s launch failure concluded that the destruction of the oxidizer turbopump led to the disintegration of the 11D55 engine, that’s shredding parts ruptured the oxidizer tank resulting in the loss of mission and vehicle.

The destruction of the oxidizer pump either resulted from the presence of FOD (Foreign Object Debris) or from an assembly violation.

Following engine replacement, the third stage for the final Soyuz-U rocket was transported back to the Baikonur Cosmodrome in Kazakhstan in mid-February, where it was brought into the Launch Vehicle Integration and Test Facility (LV ITF).

Moreover, it was announced on 21 February that all future Soyuz rocket flights (starting with Progress MS-05) carrying uncrewed Progress and crewed Soyuz capsules will fly with rocketcams to monitor the flight and stage separations.

Processing campaign for MS-05:

While the investigation and corrective actions to the third stage of its carrier rocket occurred, workers at Baikonur continued to process the Progress MS-05 spacecraft itself for launch.

On 10 February, Technical Management and the State Commission confirmed Progress MS-05’s readiness for propellant fueling and compressed gases filling operations following completion of loading operations of the final dry cargo elements of Progress’ payload.

All told, Progress MS-05 is carrying nearly 3 tonnes of supplies, equipment, food, clothing, consumables, and Station maintenance items to the ISS.

Among the various payload elements is an Orlan-MKS spacesuit.

The first new Orlan-MKS suit was lost on Progress MS-04. Because of this loss, it’s unknown at this point whether the sole Russian EVA scheduled for this year will be able to take place, as the EVA can only occur once two Orlan-MKS suits are aboard Station.

By 14 February, Progress was fueled and filled with compressed gas and was subsequently delivered to the Spacecraft Assembly and Testing Facility (SC ATF), where it was mated to its transfer compartment on 16 February.

This was followed by the designer’s inspection, which occurred on 17 February, and encapsulation into its payload fairing that same day.

Late on the 17th, the encapsulated Progress MS-05 spacecraft was transported from the SC ATF to the LV ITF.

On 18 February, Progress was mated to the third stage of its Soyuz-U booster, and the third stage was subsequently mated to the second/core stage of the Soyuz.

Following final engineering review and approval, the Soyuz-U rocket with Progress MS-05 attached was transported by rail to Gagarin Start, pad 1/5 at Baikonur on the morning of 20 February.

Once erected on the launch stand, the launch table was rotated to align the Soyuz-U into the proper orientation so that its pitch maneuver will result in the rocket flying on the correct azimuth to orbit.

The veteran Soyuz-U rocket lacks the ability to perform a roll maneuver in flight; thus that element of flight must be accounted for by the launch pad.

Launch timeline and major milestones:

Progress MS-05 lifted off from Baikonur at 05:58:33 GMT (00:58:33 EST; 11:58:33 local time) on the final Soyuz-U rocket.

Twenty-seconds prior to liftoff, the Soyuz-U’s four strap-on boosters and core stage engine began their ignition sequences, ramping up to full thrust for last-second health checks before the vehicle was released from the pad.

At liftoff, the four boosters – each measuring 19.6 m (64 ft) in length and 2.68 m (8.8 ft) in width – produced a combined total thrust from their RD-117 engines of 342,009 kgf (754,000 lbf) while the core stage’s RD-118 engine produced 80,830 kgf (178,200 lbf).

Total liftoff thrust of the Soyuz-U was 422,839 kgf (932,200 lbf).

Once airborne, the rocket ascended vertically for the first few seconds before performing a pitch maneuver to begin its downrange track over Kazakhstan and the Russian Federation.

The four boosters, each burning 39,598.6 kg (87,300 lbs) of LOX (Liquid Oxygen) and RP1 (rocket refined kerosene), helped push Soyuz through the dense lower atmosphere and accelerate the rocket to 1.5 km/s (0.9 mps).

At T+1 minute 58 seconds, the boosters separated from the core stage, having consumed a combined total of 158,394.4 kg (149,199.87 lbs) of propellant.

Booster separation marked the technical completion of first stage flight, with core stage’s RD-118 engine taking over sole propulsive duties after assisting the four boosters during first stage flight.

The core stage of the Soyuz-U stood 27.1 m (88.9 ft) tall, was 2.95 m (9.7 ft) in diameter, and was powered by a single RD-118 engine.

Carrying 92,986 kg (205,000 lbs) of LOX/RP-1 propellant, the core stage’s RD-118 engine produced a maximum thrust of 10,096.9 (kgf) 222,600 lbf during flight.

During second stage flight, the payload fairing was jettisoned at T+2 minutes 39 seconds at an altitude of 85 km.

Second stage flight culminated at T+4 minutes 45 seconds via a hot staging event that saw the shutdown of the RD-118 core stage engine followed two seconds later, at T+4 minutes 47 seconds, by the ignition of the third stage engine.

Once the ignition command to the third stage was issued, a separate command to the pyrotechnic system between the core and third stages severed the connecting bolts.

The third stage’s 11D55 engine produced 30,391 kgf (67,000 lbf) and carried 22,811 kg (50,290 lbs) of LOX/RP-1.

The third stage – 6.7 m (22 ft) long and 2.66 m (8.7 ft) in diameter – took the Progress MS-05 spacecraft to its initial orbit via a 3 minute 58 second burn.

Progress MS-05 separated from the third stage at T+8 minutes 49 seconds, at which point Progress was in a 193 by 245 km orbit inclined 51.66° to the equator.

Once Progress registered its separation from the third stage, the spacecraft commanded the deployment of its solar arrays and KURS navigation antennas and initiated pressurization of its Unified Propulsion System.

Shortly after this, Progress MS-05 passed over the new ground tracking station near Vostochny Cosmodrome in Russia’s far east.

Communication between Progress and this tracking station helped confirm the vehicle’s initial health and orbital parameters.

Additionally, Progress MS-05 finalized S-Band uplink ability from the newly activated ground tracking station – which is understood to be the final element needed to certify the facility as operational, thus allowing same-day launch and docking operations of the new MS- series of Progress and Soyuz vehicles with the International Space Station.

Since that is not yet possible, Progress MS-05 performed a standard, two-day rendezvous with the Station, arriving for an automated docking at the Station’s Pirs docking compartment on Friday, 24 February at 03:30 EST.

In all, Progress MS-05 was the 157th Progress mission since the program began in 1978 for resupply efforts of the Salyut 6 space station and the 68th Progress mission to the ISS, counting the two Progress flights that were not designated as resupply missions because they delivered module elements to the Station.

Including Wednesday’s launch, 68 Progress missions have launched to ISS to date, with Progress MS-05/66P being the 65th Progress to successfully reach orbit, following the Progress 44 launch failure in August 2011, the Progress 59 launch mishap in April 2015, and the Progress 65 launch failure in December 2016.

Soyuz-U’s retirement flight – 43 years and 787 missions:

The successful flight marked the 786th and final flight of the Soyuz-U rocket.

Production of this Soyuz rocket variant was discontinued in April 2015 following disintegration of political relations between the Russian Federation and Ukraine, where portions of the Soyuz-U’s guidance system was built.

With Progress MS-05, the Soyuz-U completed an historic career – with the rocket being the longest-serving launch vehicle in history after entering service on 18 May 1973.

The first flight of Soyuz-U lofted the Kosmos 559, a Zenit military surveillance satellite, to orbit.

Since that first mission, the Soyuz-U conducted 786 launches, 765 of which were successes and 22 of which were failures – including the Soyuz T-10a crewed mission which caught fire on the launch pad while the crew was onboard (with the crew escaping to safety via the Soyuz’s launch escape system).

For its historical numbers, the Soyuz-U fire on Soyuz T-10a, which occurred on 26 September 1983, is counted as a mission failure but not as a mission launch as the vehicle never actually left the pad.

Thus, there is a mismatch in the total number of mission successes/failures when compared to the total number of launches/flights – with 765 successes and 22 failures equalling 787 against 786 launches.

To this end, Progress MS-05 was the 787th mission of the Soyuz-U but the 786th launch of the rocket.

In all, Soyuz-U was designed in the late-1960s/early-1970s as an upgraded – hence the “U” designation – version of the original Soyuz rocket.

It was part of the R-7 family of rockets, which are based on the R-7 Semyorka missile, and was primarily constructed at the Progress Factory in Samara, Russia.

While most of its missions were uncrewed, Soyuz-U was used to launch crewed Soyuz missions.

The rocket’s first crewed flight, Soyuz 16, occurred in December 1974. Soyuz 16 was the USSR’s (Union of Soviet Socialist Republic’s) dress rehearsal for the 1975 Apollo-Soyuz Test Program flight.

Following the success of Soyuz 16, Soyuz-U launched the Soyuz 19 mission in July 1975 as the USSR’s half of the Apollo-Soyuz Test Program.

Soyuz-U also launched the Soyuz 21 mission, the first flight of a crew to the Salyut 5 space station.

In all, Soyuz-U crewed flights continued until 25 April 2002, when the rocket launched the Soyuz TM-34 spacecraft with a three-person crew for a short-duration stay aboard the International Space Station.

Soyuz TM-34 not only marked the final use of the Soyuz-U for crew transportation missions, but also the final flight of the TM-series Soyuz.

With a career spanning 43 years 9 months 4 days, Soyuz-U carries the longest lifetime of any orbital rocket and holds the record for most launches in a single calendar year of 47 flights, which occurred in 1979.

Moreover, it stands as one of the most reliable rockets in history, with a total mission success rate (including today’s MS-05 launch) of 97.204%.

(Images: Roscosmos, NASA)