Pesquet & Kimbrough complete new solar array installation on ISS

For the third time in 9 days, Thomas Pesquet and Shane Kimbrough donned their spacesuits… The post Pesquet & Kimbrough complete new solar array installation on ISS appeared first on NASASpaceFlight.com.

Pesquet & Kimbrough complete new solar array installation on ISS

For the third time in 9 days, Thomas Pesquet and Shane Kimbrough donned their spacesuits and ventured outside the International Space Station (ISS), this time to install the second of six new Boeing-built ISS Roll Out Solar Arrays (IROSAs) to the outpost — part of a program to increase the station’s electrical power capability as its science and research demands increase and future expansion plans continue.

The Extravehicular Activity (EVA) – officially known as US EVA-76 – began at 11:52 UTC / 07:52 EDT when Thomas from the European Space Agency (ESA) and Shane from NASA took their extravehicular mobility units (EMUs, or spacesuits) to battery power before exiting the Quest Airlock.

EVA-76

This was the third — and final — EVA to install the second of the first two sets of new roll-out solar arrays, this time to the 4B channel on the Port 6 (P6) truss segment of the ISS.

The EVA was largely a copy of the originally-planned US EVA-74 (see below for details), which encountered multiple EMU suit issues for Shane and an interference issue with the unfolding of the first set of new arrays. That EVA was originally supposed to see the complete installation of array #1, but that did not come to pass.

The interference issue was studied and corrected on the ground, with Thomas and Shane successfully getting the first new solar array installed on a re-planned US EVA-75 (which was originally slated to mark the installation of the second array — the one installed during EVA-76).

US EVA-76 incorporated those successful changes. For this EVA, Thomas and Shane first prepared and released the new solar array from the carrier on which it arrived aboard the CRS-22 SpaceX cargo Dragon earlier this month.

Thomas then attached himself to the end of Canadarm2; Shane and Thomas then maneuvered the array out of the carrier and, with Thomas holding on to the array, Megan McArthur, working inside the ISS at the Robotics Work Station, then drove him as far out on the station as the arm would reach. There, he passed the array back off to Shane, repositioning himself, and then took the array back for its final installation.

The duo then worked together to install it onto a mounting bracket deployed earlier this year on a previous spacewalk, rotated it to its deployment location, positioned the mounting bolts, installed the electrical cables, and drove the final two bolts to extend the array to its fully deployed position.

With the start of Quest airlock re-pressurization at 18:37 UTC / 14:37 EDT, the EVA officially came to end after 6 hours 45 minutes.

Overall, this was the 241st EVA for station construction and maintenance, the ninth spacewalk this year from the ISS, Shane’s ninth spacewalk, and Thomas’ fifth.

Previous EVA issues and successes

US EVA-74 encountered numerous issues, primarily with Shane’s suit and a hardware interference with the solar array unfolding that brought an end to the spacewalk well before the main objectives could be accomplished.

After exiting the Quest Airlock, the pair translated out to the IROSA Flight Support Equipment (FSE). However, in a somewhat sign of things to come, the hatch covering would not close at first, and Shane had to spend more time than planned getting the airlock’s fabric hatch covering configured properly.

LIVE: EVA-76 UPDATES

  • L2 ISS Section
  • Click here to Join L2
  • The FSE, pallet on which the IROSAs are attached, was removed from cargo Dragon’s trunk by Canadarm2, also known officially as the Space Station Remote Manipulator System (SSRMS) — part of the overall Mobile Base System on the station. Canadarm2 then installed the FSE onto the Mobile Base System (MBS) Payload ORU Accommodation (POA).

    After translating to the FSE, the duo began setup of the worksite and released launch restraint bolts on the IROSA. However, before the EVA could progress, two issues were noted with Shane’s suit. First, a sensor in the suit’s sublimator — which provides pressure — registered a spike. Shortly thereafter, the Display and Control Module (DCM) in his suit malfunctioned, necessitating an immediate return to the Quest Airlock to connect back to Station umbilicals to attempt a restart of the unit.

    The “warm restart” of the DCM meant that Shane’s suit momentarily lost its cooling and CO2 scrubbing capabilities; however, this is an acceptable condition, per EVA procedures, when attempting to “warm restart” a DCM. A failure to restart the unit would have meant a premature end to the EVA.

    The restart was successful, and ground teams sent Shane back out to Thomas while managers and engineers continued to discuss the sublimator issue — which itself could have also stop the EVA early. Fortunately, through a series of suit configuration tests, ground teams were able to determine that the sublimator was functioning properly and that a faulty sensor likely triggered an erroneous pressure increase reading.

    Angle showing how the new IROSAs will be deployed over the current arrays. (Credit: NASA)

    With his suit good to go, Shane translated out to the P6 truss installation site — specifically the 2B Integrated Electronics Assembly (IEA) — to begin more setup while Pesquet – mounted to the end of Canadarm2 – held on to the IROSA while he was “flown” out toward the P6 truss.

    Inside the ISS in the Robotics Work Station in the Cupola viewing module, NASA astronaut Megan McArthur controlled Canadarm2; she was the one to physically drive Thomas out toward the P6 truss.

    Due to the fact that P6 is at the very outboard end of the station, Canadarm2 cannot reach all the way to the worksite, meaning Thomas had to hand-off the IROSA to Shane, who then in turn held on to it whilst Thomas dismounted the arm and repositioned.

    Once Thomas was in position, Shane handed the IROSA back to him. The duo then aligned the IROSA onto the mounting bracket of the “Mod Kit” — which was installed during a spacewalk earlier this year — at the base of the 2B Mast Canister Assembly (MCA).

    The IROSA was first soft-docked onto the mounting bracket before an attempt to unfolded it into its deployment configuration stalled due to interference/blockage from a nearby structure. At this point, already at the six hour mark into the spacewalk, ground teams decided to have the duo photograph the interference and firmly secure the IROSA as is and end the spacewalk.

    US EVA-75 was then re-planned and occurred on 20 June to successfully complete the main objectives of US EVA-74 as well as “get ahead” tasks to reduce the amount of work needed for the next spacewalk.

    The ISS once the new arrays are installed – via Mack Crawford for NSF L2.

    After leaving the Quest airlock, the pair worked to unfold the new solar array on the 2B power channel. This time, the mitigation strategies developed on the ground worked, and Thomas and Shane were able the secure the IROSA properly before running electrical and data connections between the new array and the station’s power system.

    The crew members then successfully deployed the solar array from its flight support structure — marking the first time since 2009 that a new array was unfurled on the station. Until this spacewalk, the newest solar arrays for the station were those on the S6 truss, delivered by the STS-119 crew of the Space Shuttle Discovery.

    IROSA background

    The eight original Solar Array Wings (SAWs) on the ISS, which each produce around 30 kilowatts (kW) of power for a total of about 250kW are beginning to show signs of degradation, with the oldest array now having been in space since 2000 when the P6 truss and associated arrays was delivered to the station by Shuttle Endeavour’s STS-97 crew.

    With over 20 years of use, and normal degradation of solar arrays, the eight SAWs now only produce around 160kW of power – against a backdrop of rising power demands from the station’s increasing users.

    This led the Station program to develop the ISS Power Augmentation (IPA) plan, which called for adding six additional solar arrays to the station in order to restore the outpost’s power generation to its original levels.

    Comparison of the original and new arrays. (Credit: NASA)

    Under the IPA program, six new ISS Roll Out Solar Arrays (IROSAs) will be added. Whilst the station’s original arrays were folded up and deployed in an accordion-like manner, the IROSAs are a new type of array technology which roll out in a mat-like manner from inside a cylindrical canister.

    The IROSAs will be installed on top of six of the station’s existing solar arrays, which will allow the IROSAs to utilize the same sun-tracking motors and be connected into the same electrical system as the current arrays.

    With the IROSAs being around 30% efficient, compared to the 14% efficiency of the original arrays, the IROSAs will generate roughly the same amount of power as the originals despite being only half their size.

    Each IROSA will produce 20kW of additional power, for a total of 120kW across all six arrays.

    However, because the IROSAs are smaller, they will not completely cover the half of the six SAWs they’ll be installed over. Instead, portions of the original arrays will still be power positive.

    The unshadowed portions of the original arrays will continue to produce 95kW as a result, making for a combined total of 215kW of power available to the ISS — an increase of nearly a third compared with the outpost’s current levels.

    This first IROSA was launched along with the second aboard the SpaceX CRS-22 cargo Dragon mission that launched from Florida back on 3 June. 

    The first EVA encounter numerous issues, primarily with Shane Kimbrough’s suit and a hardware interference with the solar array deployment that brought an end to the spacewalk well before the main objectives could be accomplished.

    (Lead image: Placement of the new IROSAs over the existing station solar arrays. Credit: Mack Crawford for NSF L2)

    The post Pesquet & Kimbrough complete new solar array installation on ISS appeared first on NASASpaceFlight.com.

    Source : NASA More   

    What's Your Reaction?

    like
    0
    dislike
    0
    love
    0
    funny
    0
    angry
    0
    sad
    0
    wow
    0

    Next Article

    Russia’s Soyuz launches Pion-NKS naval intelligence satellite

    Russia launched the first satellite for its long-delayed next-generation ocean reconnaissance system on Friday. The… The post Russia’s Soyuz launches Pion-NKS naval intelligence satellite appeared first on NASASpaceFlight.com.

    Russia’s Soyuz launches Pion-NKS naval intelligence satellite

    Russia launched the first satellite for its long-delayed next-generation ocean reconnaissance system on Friday. The Pion-NKS No.901 satellite lifted off atop a Soyuz-2-1b carrier rocket from the Plesetsk Cosmodrome in Northern Russia at 22:50 Moscow Time (19:50 UTC).

    Pion-NKS is part of the wider Liana program, aimed at replacing the Soviet-era signals intelligence satellites which Russia previously used to collect and monitor radio signals from low Earth orbit. Pion replaces the Upravlenniye Sputnik – Passivny Modifikirovanny (US-PM) satellites used for naval reconnaissance, while the complementary Lotos-S satellites are replacing Tselina-2 spacecraft that were specialized for locating radio sources on land.

    The Liana project grew out of a 1994 proposal, undergoing several redesigns over the years due to changes in technology and the political environment – the latter forcing the satellites to be downsized to fit on Soyuz rockets instead of the more capable, but Ukrainian-manufactured, Zenit.

    The Pion spacecraft is equipped with both passive and active reconnaissance systems to aid in its mission to detect and track ships at sea. The passive component of the satellite’s payload consists of antennae which allow it to listen for radio signals and use these to assess the position of vessels. The active component will use radar to locate the vessels directly.

    The prime contractor for Russia’s Liana program is the KB Arsenal design bureau, who also developed the instruments used aboard the satellites, and are responsible for integrating them into the completed spacecraft. Both Lotos-S and Pion-NKS are based around a platform that was derived from the Yantar series of reconnaissance satellites, with TsSKB Progress responsible for their manufacture.

    Rendering of the Pion-NKS satellite – via KB Arsenal

    While the first prototype Lotos-S satellite launched in 2009 and operational missions began in 2014, Friday’s launch marked the first flight of the Pion-NKS. Its deployment ends a gap in Russian naval intelligence-gathering capabilities that has existed since the last US-PM satellite, Kosmos 2421, failed shortly after launch in June 2006.

    The Soviet Union began development of its naval reconnaissance satellites in the 1960s. For the first-generation system, the radar and signals intercept functions were split into two different satellites – named US-A and US-P respectively. The power requirements of the radar equipment on the US-A satellites led to a decision to equip the spacecraft with nuclear reactors, although the first six prototypes used batteries instead. The US-P satellites were powered by solar panels.

    Thirty-two operational US-A spacecraft were launched between 1970 and 1998, while thirty-seven US-P satellites were deployed between 1974 and 1991, with all launches of both types using the Tsyklon-2 rocket. In the west, these satellites became known as Radar Ocean Reconnaissance Satellite (RORSAT) and Electronic Ocean Reconnaissance Satellite (EORSAT) respectively.

    An upgraded version of the solar-powered US-P satellite, US-PM, replaced both previous series in 1993. Thirteen were launched – also using Tsyklon-2 rockets – with the last reaching orbit in June 2006. Despite a successful launch, one of the satellite’s solar panels failed to deploy properly. In March 2008, the satellite was reported to have disintegrated in orbit, producing over 500 catalogued pieces of debris.

    Pion-NKS Updates

  • Russian Launchers Section
  • L2 Russian Section
  • Click here to Join L2
  • Most of Russia’s military satellites are given official names of the word “Kosmos” – Russian for “Space” – followed by a sequential number. This practice began in 1962, and the series of Kosmos satellites has historically also included uncrewed test flights of the Vostok, Voskhod and Soyuz spacecraft, as well as failed interplanetary probes which found themselves stranded in Earth orbit.

    Today these numbers are only used for military spacecraft. Since the designations are sequential, Pion-NKS No.901 is expected to become Kosmos 2560, assuming no previously-undisclosed satellites have been deployed from other military spacecraft in orbit since Russia’s last military launch in February.

    The Pion satellite rode to orbit atop a Soyuz-2-1b carrier rocket. Soyuz-2-1b is the latest and most powerful version of the Soyuz rocket that has served Russia, and formerly the Soviet Union, since the 1960s.

    Soyuz itself is a derivative of Sergei Korolev’s R-7 missile, which was the first intercontinental ballistic missile (ICBM) to fly, making its first launch in 1957. R-7 served as the basis for several closely-related families of rockets, including Vostok, Voskhod, Molniya and Soyuz – the latter of which is the only one that remains in service.

    Three versions of Soyuz are currently in use, Soyuz-2-1a, 2-1b and 2-1v. Soyuz-2-1a was developed as a direct modernization of the previous-generation Soyuz-U, while Soyuz-2-1b introduces further upgrades to carry heavier payloads. The Soyuz-2-1v design features a redesigned and re-engined Blok-A core stage without the four distinctive boosters that make up the first stage of other Soyuz rockets, and is designed to carry smaller payloads at a lower cost.

    A Soyuz-2-1b launches a GLONASS-K navigation satellite from Plesetsk in October 2020 – via Roscosmos

    Soyuz-2-1a was the first of the three Soyuz-2 configurations to fly, making a suborbital test flight in November 2004 and an initial orbital launch in October 2006. The first Soyuz-2-1b launch was made in December 2006 with the French CoRoT space telescope as its payload. These versions slowly replaced the earlier Soyuz-U on military, commercial and ISS resupply launches, as well as Soyuz-2-1a replacing the interim Soyuz-FG for crewed launches. The last Soyuz-U was launched in February 2017, and Soyuz-FG followed it into retirement in September 2019.

    The smaller Soyuz-2-1v was introduced in 2013, and is intended to replace smaller rockets in Russia’s fleet, such as Rokot, Kosmos-3M and Tsyklon.

    Soyuz can launch from four different launch sites: the Baikonur Cosmodrome in Kazakhstan, the Plesetsk and Vostochny Cosmodromes in Russia, and the Guiana Space Center in Kourou, French Guiana. Friday’s launch took place from Plesetsk, which is Russia’s main launch site for military satellites.

    While Plesetsk originally had four R-7 launch pads, only two are still in use with Soyuz-2. These are Pads 3 and 4 at Site 43.

    Prior to launch, Soyuz was assembled horizontally in the integration hangar, or MIK, before being transported to the launch pad by rail. The rocket was then raised vertical and enclosed in the pad’s petal-like gantry structures. These allowed access to the vehicle and its payload while the vehicle was at the launch pad.

    The three-stage Soyuz-2-1b rocket burned RG-1 propellant – the Russian designation for rocket-grade kerosene – oxidized by liquid oxygen. The first stage consisted of four boosters – Blok-B, V, G and D – clustered around the second stage, Blok-A. Each of the four boosters was powered by a single RD-107A engine. Blok-A had an RD-108A engine, a modification of the RD-107A incorporating vernier nozzles to help steer the rocket.

    Close-up photo of the Soyuz-2-1b engines during the launch of 3 Gonets-M satellites in December 2020 – via Roscosmos

    The first and second stages burned together during the early phases of ascent. The five engines ignited about sixteen seconds before liftoff, building up thrust as the clock ticked towards zero. With the engines at full thrust and the countdown at zero, the launch pad swing arms came open and Soyuz began to ascend.

    First stage separation occurred around 118 seconds into the flight, with the four boosters venting residual oxygen through valves in their noses to push them away from the still-firing second stage. The “Korolev Cross” was formed in the sky by the four boosters falling away from the rocket, named after the rocket’s Chief Designer.

    After staging, the second stage continued to burn for another 170 seconds. Towards the end of this burn, the rocket’s payload fairing separated.

    The third stage used a “fire-in-the-hole” separation, igniting its RD-0124 engine while the second stage was still burning. The interstage between the two stages was designed to allow exhaust gasses to escape between ignition and stage separation. Shortly after staging, the third stage’s aft skirt was jettisoned, splitting into three pieces and falling away.

    The third stage injected the Pion-NKS satellite into low Earth orbit. Spacecraft separation took place a few moments after third stage shutdown.

    Friday’s launch was Russia’s ninth of 2021, all of which have used Soyuz rockets. It was Russia’s first military launch since February, when another Liana satellite – a Lotos-S1 – was deployed by another Soyuz-2-1b.

    Roscosmos Director General Dmitry Rogozin recently admitted that Western sanctions against Russia had impacted the country’s space activities, particularly through a lack of availability of electrical components for satellites. This has contributed to Russia’s low flight rate, with four of the nine launches to date this year having exclusively carried commercial payloads.

    (Lead photo from Gonets-M launch in December 2020 via Roscosmos)

    The post Russia’s Soyuz launches Pion-NKS naval intelligence satellite appeared first on NASASpaceFlight.com.

    Source : NASA More   

    This site uses cookies. By continuing to browse the site you are agreeing to our use of cookies.