Sunday, October 15, 2017

Progress MS-07 Launches Toward the International Space Station

A Soyuz-2.1a with Progress MS-07 launches on Oct. 14, 2017. Photo Credit: Roscosmos

Russia’s Progress MS-07 cargo craft launched toward the International Space Station (ISS) at 4:46 a.m. EDT (08:46 GMT) Oct. 14, 2017, from the Baikonur Cosmodrome located in Kazakhstan. The cargo vessel was sent aloft atop a Soyuz 2.1a rocket with liftoff taking place two days later than originally planned as the first attempt was scrubbed because of an undisclosed issue within the final minute of the countdown.

Because of the delay, Russian officials abandoned plans to test out a new two-orbit rendezvous flight profile that is hoped will shorten Progress, and eventually Soyuz, flights to the space station to just 3.5 hours. Lately, Roscosmos has been sending its crewed and cargo vessels to the outpost using a four-orbit profile to arrive at the orbital laboratory in a little less than six hours.

However, the two- and four-orbit profiles require precise orbital alignments. Because of the delay, neither was possible for the Oct. 14 launch. Instead, the spacecraft will take the longer 34-orbit route, taking two days to arrive at the ISS.

It is unclear when the Russian space agency will try to test out the technique again. It traditionally tests new techniques and features using the robotic Progress spacecraft before applying them to the crewed Soyuz vehicles. As such, the next opportunity might come in February of 2018. If it is tested successfully, it could be used for future crewed Soyuz missions.

Preparations for the Progress MS-07 mission commenced in September with initial tests and checkouts of the spacecraft. The campaign entered its decisive phase on Sept. 26 when Roscosmos decided to start fueling the freighter with propellant components and compressed gases. This process was concluded three days later and the spacecraft was then delivered to the integration and test facility for final processing operations.

During the first days of October, engineers were busy conducting final cargo packing, installing the spacecraft on the launch vehicle adapter ring, and performing inspections. Progress, encapsulated in a payload fairing, was attached to the launch vehicle on Oct. 9. The rollout of the Soyuz 2.1a rocket to the launch pad was completed one day later.

At the end of the Oct. 14 countdown, the Soyuz 2.1a with Progress MS-07 thundered off the pad at Site 31/6. The rocket started its standard short vertical climb, powered by its four liquid-fueled strap-on boosters. These boosters, utilizing RD-107A engines, lifted the vehicle skyward and were jettisoned about two minutes into the flight. Then the rocket’s core stage took control over the mission accelerating the launch vehicle for nearly three more minutes before it was also detached.

Afterward, the third stage started its job of boosting the launch vehicle toward its designated orbit. Using an RD-0110 engine, this stage controlled the flight for slightly more than four minutes, culminating in an engine cutoff and a successful deployment of the Progress MS-07 spacecraft some nine minutes after liftoff.

After separation, the Progress vehicle deployed its solar arrays and communication antennas.

The mission was then handed over to the Mission Control Center in Moscow where its controllers declared the spacecraft was successfully inserted into orbit.

Progress MS-07 is carrying about 2.9 tons (2.7 metric tons) of supplies to the orbiting outpost. This includes 1,940 pounds (880 kilograms) of propellant, 51 pounds (23 kilograms) of oxygen, 926 pounds (420 kilograms) of water, and 2,976 pounds (1,350 kilograms) of food, cargo, and equipment for the six-person Expedition 53 crew.

Once Progress catches up with the ISS early on Monday morning, Oct. 16, the spacecraft will line up and dock with the station’s Earth-facing Pirs module. It will remain attached to that port until March of next year (2018) when it will be commanded to leave the laboratory, to deorbit and burn up in Earth’s atmosphere.

Progress-MS, which is manufactured by RKK Energia, is an improved variant of the Progress automated cargo spacecraft that has been used to deliver supplies to the space station. It has a similar size, mass, and cargo capacity as the modified Progress-M employed previously in this role.

The MS variant features a series of upgrades. The improvements include the addition of an external compartment that enables deployment of small satellites, the addition of a backup system of electrical motors for the docking and sealing mechanisms, and additional panels in the cargo compartment that provides increased protection from micrometeoroids.

Progress-MS also has a number of upgrades in terms of telemetry and navigational systems as well as a new digital communication system that enables enhanced TV camera views during docking operations.

The first Progress-MS spacecraft was launched by Russia on Dec. 21, 2015, via a Soyuz 2.1a rocket. It delivered some 5,500 pounds (2,500 kilograms) of cargo to the ISS.

The Soyuz 2.1a rocket design that was used for the Oct. 14, 2017, flight stands 151 feet (46.1 meters) tall and has a diameter of 9.68 feet (2.95 meters). It can deliver payloads of up to 8.6 tons (7.8 metric tons) to low-Earth orbit and 3.1 tons (2.8 metric tons) to a geostationary transfer orbit.

This version of the rocket includes a conversion from an analog to digital flight control system as well as uprated engines on the first stage booster with improved injection systems. While the rocket is suitable for cargo flights to the ISS with an increased upmass, it will have to be human-rated before crewed missions fly atop the vehicle.

Soyuz 2.1a has four liquid-fueled strap-on boosters with RD-107A engines providing extra lift during the initial phase of the flight. The rocket’s core stage, powered by an RD-108A engine, acts as both first and second stage. It is 91.2 feet (27.8 meters) long and 9.68 feet (2.95 meters) in diameter. The third stage, with an RD-0110 engine, is 22.11 feet (6.74 meters) in length and 8.73 feet (2.66 meters) in diameter.

Saturday’s mission was the second Soyuz 2.1a launch and the 11th liftoff from Baikonur in 2017. It was also the 16th flight to orbit for Russia in 2017.

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