Progress MS-16 performs Pirs' disposal
The 77th Russian cargo supply flight to the International Space Station, ISS, lifted off on February 15, with the unusual task of discarding the veteran Pirs Docking Compartment, SO1, from the Russian Segment of the outpost, to make way for the long-awaited MLM Nauka module later in 2021. On February 17, Progress MS-16 docked at ISS under the manual control of the station's crew, after a last-minute problem with the automated rendezvous system.
Progress MS-16 mission at a glance:
Progress MS-16 flight program
During the early revisions of the ISS flight manifest, the Progress MS-16 cargo mission ended up in the timeframe when Roskosmos planned to launch the long-awaited MLM Nauka module. A few days before the Nauka's arrival, the Pirs Docking Compartment, SO-1, had to vacate the nadir (Earth-facing) port of the Zvezda Service Module, where the new spacecraft would be permanently parked. Nauka could not be docked to Pirs because the light thin-walled module was not structurally designed to hold the 20-ton new comer. Neither had Pirs its own propulsion system, requiring a space tug for disposal maneuvers. A departing cargo ship could perform the operation with just some extra avionics retrofitted into the vehicle during its pre-launch processing in Baikonur.
By the Fall of 2019, the ISS flight manifest set the launch of Progress MS-16 for December 11, 2020, placing the end of its 220-day stay at the station toward the middle of 2021. At the same time, the launch of MLM Nauka was increasingly likely to slip from the end 0f 2020 well into 2021, thus giving Progress MS-16 a back-up role as a "burial" vehicle for the Pirs module.
At the time, the primary role of discarding Pirs was still assigned to the Progress MS-15 mission, however a delay with the December 2020 launch of the Nauka would shift the responsibility to Progress MS-16, because mission control wanted to keep Pirs at the station until the arrival of Nauka was imminent. In case of Progress MS-16 launch on December 11, 2020, the cargo ship would dock at Pirs on December 13, 2020, and would be ready to depart with the retiring module on April 23, 2021, just three days after the launch of Nauka. Progress MS-16 and Pirs would be deorbited on the day of their undocking from the ISS.
However, according to the preliminary version of the ISS flight manifest drafted by Roskosmos at the end of August 2020, the task of discarding Pirs was still assigned to Progress MS-15, while Progress MS-16 would be docked to the aft port of the Zvezda Service Module, SM, for a routine supply mission concluding in mid-March 2021, after just 96 days in orbit.
Finally, by late Fall 2020, the launch of Nauka slipped from April to July 2021, dropping the task of Pirs disposal into the Progress MS-16's lap. The exact launch date of Progress MS-16 could change depending on the status of the MLM launch (Insider Content).
In early October 2020, RIA Novosti quoted Roskosmos press-service as saying that the Progress MS-16 and Arktika-M missions had been postponed until 2021 due to the need for additional checks. The delay was probably related to the payload fairing separation issue during the launch of Progress MS-15 cargo ship on July 23, 2020.
Before the end of 2020, the launch of Progress MS-16 was set for February 15, 2021, on a 152-day mission, concluding with its departure from the ISS in a joint stack with the Pirs Docking Compartment, a couple of days after the launch of Nauka, then planned for July 15, 2021.
Preparations for flight
Soyuz-2-1a vehicle with Progress M-16 is being installed on the launch pad at Site 31 on the morning of Feb. 12, 2021.
On January 18, 2021, Roskosmos announced that specialists from the Yuzhny space center and RKK Energia had started processing operations with the Progress MS-16 cargo ship and the Soyuz MS-18 crew vehicles.
On February 1, 2021, Roskosmos announced that the technical management meeting in Baikonur had cleared Progress MS-16 for fueling of its tanker module and the integrated propulsion unit, ODU, with propellant components and pressurized gases. Before its transfer to the fueling station, the spacecraft had undergone weighting and balancing, Roskosmos said.
On February 4, Roskosmos said that Progress MS-16 had been installed back into its processing stand inside the assembly building at Site 254 for final pre-launch operations and loading of fresh food items in its cargo bay.
The ship's cargo included 600 kilograms of propellant for refueling, 420 liters of drinking water in the Rodnik system, 40.5 kilograms of pressurized gases with extra nitrogen supplies and 1,400 kilograms of various equipment and supplies, including the repair kit with reinforced glue patches for temporary sealing of the air leak (Insider Content) in the Transfer Chamber, PrK, in the Zvezda Service Module, SM, Roskosmos said. The cargo also included 31 kilograms of equipment and materials for Russian scientific experiments Neirolab, Aseptik, Fotobioreaktor, Kaskad and Biodegradatsiya.
Mass breakdown of the cargo delivered aboard Progress MS-16, according to the mission control in Korolev:
The integration of the spacecraft with its launch vehicle adapter was performed on February 5 and on February 9, specialists conducted the traditional visual inspection of the ship, after which it was lowered into horizontal position and rolled inside its protective fairing. Following a launch readiness test, the assembled payload section was transferred from the spacecraft processing building at Site 254 to the vehicle assembly building at Site 31 on February 10, for integration with its Soyuz-2-1a rocket, which was completed on February 11.
The fully assembled vehicle was rolled out to the launch pad at Site 31 on the morning of February 12, 2021. The transport-erector system began moving at 5:30 in the morning Moscow Time and upon the arrival at the pad, the launch vehicle was installed in vertical position, enclosed in the access gantry and launch pad interfaces were connected to the rocket. According to the processing schedule of the first day on the pad, specialists conducted autonomous tests of all systems aboard the spacecraft and the launch system and analyzed the resulting telemetry data. On February 13, Head of Roskosmos Dmitry Rogozin announced that general tests had been performed with flying colors and all the work of the second day on the pad had been completed.
Several hours before the scheduled liftoff on February 14, Roskosmos said that the last-minute cargo was being loaded into the cargo ship and the rocket was being prepared for fueling. The State Commission overseeing the launch met at 03:40 Moscow Time and cleared the launch vehicle for fueling which started at 04:10 Moscow Time. The completion of the process and the withdrawal of fueling vehicles from the pad was scheduled around 06:15 Moscow Time.
A Soyuz-2-1a rocket carrying the Progress MS-16 cargo ship to the ISS is scheduled to lifted off on February 15, 2021, at 07:45:06.310 Moscow Time (11:45 p.m. EST on February 14) from Site 31 in Baikonur.
Following vertical liftoff under the combined thrust of the four RD-107 engines on the first stage and the single RD-108 of the second (core) stage, the launch vehicle headed eastward from Baikonur matching its ground track to an orbit inclined 51.67 degrees to the plane of the Equator. The four first-stage boosters separated nearly two minutes into the flight, followed by the split and drop of the two halves of the payload fairing slightly more than a minute later. In the meantime, the second stage continued firing until 4.7 minutes into the flight.
The third stage then ignited moments before the separation of the second stage, firing its RD-0110 engine through a lattice structure connecting the two boosters and ensuring a continuous thrust during the separation process. A fraction of a second after the boosters of the second and third stage parted ways, the aft cylindrical section of the third stage split into three segments and dropped off, ensuring the fall of the second stage and the aft section into the same drop zone.
The Progress MS-16 separated from the third stage of the launch vehicle at 07:53:55 Moscow Time entering an initial parking orbit as planned.
The onboard camera and reports from mission control confirmed that all antennas and solar panels aboard the vehicle had deployed.
The Russian mission control in Korolev displayed the following deployment sequence:
According to Roskosmos, Progress MS-16 entered a planned orbit with the following parameters:
At the time, when Progress MS-16 entered orbit, the ISS was flying over the Southern Atlantic at an altitude of more than 400 kilometers.
Three minutes after reaching orbit, mission control planned a routine four-minute test of the ship's Kurs rendezvous system. Then between 09:23 and 09:31 Moscow Time, the spacecraft was scheduled to deploy its docking mechanism.
Some docking antenna damage (right) was clearly visible on images of the approaching Progress MS-16.
Following its successful launch on February 15, 2021, the Progress MS-16 mission was designed to follow a two-day, 34-orbit rendezvous profile to reach the International Space Station, ISS.
According to Roskosmos, on February 16, 2021, at 08:51 Moscow Time (12:51 a.m. EST), Progress MS-16 conducted a planned orbit correction maneuver on its way to the ISS. Five more firings had followed using the ship's main SKD engine and small DPO thrusters, before the spacecraft started a routine flyaround of the station and the final approach at the 417.627 by 438.245-kilometer orbit of the ISS.
Orbital maneuvers of Progress MS-16 during its autonomous rendezvous with ISS on February 17, 2021:
The autonomous rendezvous process between Progress MS-16 and the station was planned according to the following timeline:
During its 33rd orbit around the Earth, Progress MS-16 was reported to be in a 382.027 by 425.260-kilometer orbit.
During the final approach, Russian cosmonauts Sergey Ryzhikov and Sergey Kud'-Sverchkov from the Soyuz MS-17 crew, were at the console of the remote control system, TORU, inside the Zvezda Service Module, SM, a part of the Russian ISS Segment, ready to switch to manual docking mode in case of problems with the automated system.
Indeed, just meters away from the station, as Progress MS-16 had completed a 56-degree flyaround of the station, aligned itself with the destination docking port at a distance of around 400 meters and began the final approach, the spacecraft made an unexpected roll maneuver around 20 meters from the station. When the deviation had exceeded allowable 30 degrees, mission control aborted the automated berthing, instructed the crew to activate the TORU mode and to command the spacecraft to back away from the station to a distance of 30 meters. After guiding the cargo ship away from the station, Sergei Ryzhikov was able to stabilize the wayward spacecraft and, after a short period of station-keeping, proceeded with the docking under manual control with the approval from the ground. According to Roskosmos, the first contact and the mechanical capture between the cargo ship and the station took place at 09:26:47 Moscow Time, or between three and six minutes behind schedule. (NASA reported the docking time as 1:27 a.m. EST, as the two spacecraft were flying over Argentina). The closure of the peripheral hooks of the docking port on the cargo ship was reported to take place at 09:32:02 Moscow Time, according to the mission control in Korolev.
According to one industry source, the failure of the automated docking was caused by the bent dish of the ASF antenna which performs precise measurements of the ship's positioning during its approach to the station. Specialists suspected that the antenna dish could have been damaged by a fragment of the separating payload fairing during the ship's ascent to orbit, essentially repeating incidents during launches of the Progress MS-15 and Progress MS-13 cargo ships.
Experts noticed that all three anomalies during the separation of the payload fairing have taken place since the transition of the Progress launches from the Soyuz-U/FG rocket variants to the newer Soyuz-2 vehicle. The design of payload section on both versions of the rocket is believed to be the same, but the separation of the fairing on Soyuz-2 takes place earlier, because the vehicle's new digital control system affords a more flexible control of the ascent trajectory.
A commission was formed to investigate an issue, a source told RussianSpaceWeb.com.
On May 12, 2021, Roskosmos announced that the propulsion system of the Progress MS-16 cargo ship would be used for the ISS orbit correction scheduled for May 20, 2021, to put the station in the path for a rendezvous with the Soyuz MS-19 crew vehicle and to provide a landing opportunity for Soyuz MS-18.
According to calculations of the Russian mission control, the engines aboard Progress MS-16 will initiate a pre-programmed firing at 20:01 Moscow Time lasting 180 seconds. The maneuver will add 0.2 meters per second to the station's velocity boosting its average altitude by 350 meters to 419.72 kilometers.
According to preliminary estimates, after the orbit correction, the ISS will be in orbit with the following parameters:
After the manuever, Roskosmos said that the engine of Progress MS-16 had fired for 180.7 seconds and resulted in the average altitude of the station equal 419.69 kilometers. The post-correction orbital parameters were found to be as following:
On June 15, 2021, Roskosmos announced that the propulsion system of the Progress MS-16 cargo ship would be used for another ISS orbit correction scheduled for June 24, 2021, to provide necessary orbital parameters for a rendezvous with the Soyuz MS-19 crew vehicle and to give a planned landing opportunity for Soyuz MS-18. (On June 24, Roskosmos said that the orbit correction would provide orbital parameters for the launch of Boeing's CST-100 Starliner spacecraft, as well as Soyuz MS-19 launch and Soyuz MS-18 landing.)
According to the preliminary calculations of mission control, the engines of Progress MS-16, docked at the Pirs Docking Compartment, SO1, will be fired at 05:25 M0scow Time, delivering 0.5 meters per second in the station's velocity change.
After the correction on June 24, Roskosmos announced that the propulsion system aboard Progress MS-16 had been activated at 05:40 Moscow Time and fired for 466 seconds, amounting to 0.5 meters per second in the station's velocity change and leaving the ISS in an orbit with an average altitude of 420.28 kilometers. The exact orbital parameters were as following:
At the time, the spacecraft was orbiting the Earth over the Eastern China and within communications range of Russian ground stations.
Within four minutes (13:59:00 Moscow Time, according to schedule), Progress MS-16 performed a short separation burn to increase distance from the ISS. The deorbiting maneuver was planned within around three hours to ensure the reentry of the Pirs/Progress stack over the Pacific.
Progress MS-16 initiated braking maneuver as planned at 17:01 Moscow Time (10:01 a.m. EDT) and after a 1,057-second (17.6-minute) burn, the module/cargo ship duo reentered the dense atmosphere at 17:42 Moscow Time (10:42 a.m. EDT).
An artist rendering depicting the disposal of the Pirs Docking compartment with the help of the Progress cargo ship. Click to enlarge. Copyright © 2019 Anatoly Zak
A photo dated Nov. 6, 2020, shows the start of the Progress MS-16 launch campaign inside processing building at Site 254 in Baikonur. The MLM Nauka module can be seen on the right. Click to enlarge. Credit: Roskosmos
Progress MS-16 is being prepared for transfer to a fueling facility on February 1, 2021. Click to enlarge. Credit: Roskosmos
Loading of the final cargo items aboard the Progress MS-16 spacecraft on February 4, 2021. Click to enlarge. Credit: Roskosmos
Payload section with Progress MS-16 spacecraft is being prepared for shipment to the vehicle assembly building for integration with the Soyuz-2-1a rocket on February 10, 2021. Click to enlarge. Credit: Roskosmos
Final assembly of the Soyuz-2-1a rocket with Progress MS-16 spacecraft at Site 31. Click to enlarge. Credit: Roskosmos
Soyuz-2-1a rocket with Progress MS-16 shortly after arrival at launch pad on Feb. 12, 2021. Click to enlarge. Credit: Roskosmos
Access gantry is being retracted from the Soyuz rocket around half an hour before the liftoff of Progress MS-16. Click to enlarge. Credit: Roskosmos
Soyuz-2-1a rocket lifts off with Progress MS-16 on Feb. 15, 2021. Click to enlarge. Credit: Roskosmos
An external camera showed separation of the first stage boosters during the launch of Progress MS-16. Click to enlarge. Credit: Roskosmos
An external camera showed separation of the payload fairing during the launch of Progress MS-16. Click to enlarge. Credit: Roskosmos
Progress MS-16 separates from the third stage of the launch vehicle upon reaching orbit. Credit: Roskosmos
Solar panel deployment aboard Progress MS-16 shortly after separation from the third stage of the launch vehicle. Credit: Roskosmos
Initial approach of Progress MS-16 to the station went normally. Click to enlarge. Credit: Roskosmos
A potential antenna damage visible on the Progress MS-16 during its approach to the station on Feb. 17, 2021. Click to enlarge. Credit: Roskosmos
At 09:08 Moscow Time on February 17, 2021, Progress MS-16 completed roll manuever and it was well aligned with its destination docking port while being less than 200 meters from the ISS. Click to enlarge. Credit: Roskosmos
At 09:18 Moscow Time, or two minutes before planned docking, Progress MS-16 appeared to be off its planned position on the roll axis. Click to enlarge. Credit: Roskosmos
Progress MS-16 appeared to be back on target under manual control by 09:23 Moscow Time. Click to enlarge. Credit: Roskosmos
Sergey Ryzhikov during a remote control docking exercise aboard the ISS on Feb. 9, 2021. Click to enlarge. Credit: Roskosmos