Pesquet & Kimbrough continue new solar array installation on ISS

For the third time in 11 days, Thomas Pesquet and Shane Kimbrough have donned their… The post Pesquet & Kimbrough continue new solar array installation on ISS appeared first on NASASpaceFlight.com.

Pesquet & Kimbrough continue new solar array installation on ISS

For the third time in 11 days, Thomas Pesquet and Shane Kimbrough have 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 will be the third — and final planned — extravehicular activity to install the second set of new roll-out solar arrays, this time to the 4B channel on the Port 6 (P6) truss segment of the ISS.

The EVA will largely be 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 arrays.

The interference issue was studied and corrected on the ground, with Thomas and Shane successfully getting the first new solar arrays installed on a re-planned US EVA-75 — which was needed to get the first array firmly attached to the station.

US EVA-76 will incorporate those successful changes, and the plan is for the second array to be fully installed and unfurled today.

For this EVA, Thomas and Shane will first prepare and release the new solar array from the carrier on which it arrived aboard the CRS-22 SpaceX cargo Dragon earlier this month.

Thomas will then attach himself to the end of Canadarm2.  With Megan McArthur driving the arm and Thomas, Shane and Thomas will maneuver the array out of the carrier. Megan will then drive Thomas on the end of the arm as far out on the station as it can reach. There, he will pass the array off to Shane before repositioning himself to take back the array for its final installation.

The duo will then work together to install it, rotate it to its deployment location, position the mounting bolts, install the electrical cables, and drive the final two bolts to extend the array to its fully deployed position.

Overall, this will be the 241st EVA for station construction and maintenance.  This will also be 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.

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  • 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 continue new solar array installation on ISS appeared first on NASASpaceFlight.com.

    Source : NASA More   

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    Iridium wins contract to develop hosted payload for Low Earth Orbit

    Iridium has secured a $30 million research and development contract with the United States Army… The post Iridium wins contract to develop hosted payload for Low Earth Orbit appeared first on NASASpaceFlight.com.

    Iridium wins contract to develop hosted payload for Low Earth Orbit

    Iridium has secured a $30 million research and development contract with the United States Army to develop a payload which will support the concept of a rapidly deployable small satellite constellation, with the goal of providing more effective data transmission to the soldiers in the field.

    The payload will be hosted by another Low Earth Orbit commercial satellite constellation and used alongside Iridium’s existing network. Although the partner is not yet announced, it could include mega-constellations like SpaceX’s Starlink, Amazon’s upcoming Project Kuiper, or satellites of the OneWeb and ViaSat constellations.

    “This is one of the largest engineering contracts in Iridium’s history, and we’re pleased to once again bring the value of Iridium and our partner ecosystem to the fore at the request of the United States Army,” said Matt Desch, CEO of Iridium.

    “It also represents another phase in the evolution of our growing relationship with the DoD (Department of Defense), and we’re excited to engage in this experimental multi-constellation adaptation of our service.”

    The experimental payload will be based on Iridium’s one-to-many global broadcast service, named Iridium Burst. Announced in 2014, Iridium Burst makes it possible to transmit data to millions of devices at a time using the high power channels of Iridium’s existing satellite network.

    Coverage map of the Iridium NEXT satellite constellation – via Iridium

    It is especially useful for businesses, government agencies and the military to broadcast data. The development is also supported by Colorado-based Aerospace company, SEAKR Engineering, and Virginia-based Satellite company, Satelles Inc as subcontractors.

    “Iridium has always been focused on providing innovative, reliable and high-value services to the U.S. warfighter,” said Scott Scheimreif, Executive Vice President of Government Programs at Iridium. “This program can help add to warfighter readiness to conduct a full range of military operations at a tactical level. This includes the ability to enhance effectiveness of military units, weapons and equipment during combat against near-peer adversaries.”

    This project was initiated through an “Other Transaction Agreement” (OTA). The U.S’ Department of Defense created the Other Transaction Agreement to carry out the development and procurement of prototype projects and streamline the process for adopting new technologies.

    Iridium’s own Iridium NEXT constellation was launched over the course of eight SpaceX Falcon 9 launches, with replenishment launches on contract with Relativity Space. CEO Matt Desch has also previously mentioned the possibility of Iridium working together with the Starlink constellation. However, the constellation(s) that Iridium will partner with for this newest contract is to be announced.

    Iridium’s Operation Arctic Lynx

    Iridium also recently announced a series of partnership-driven field exercises deploying Iridium technologies used by organizations primarily in the latitude of 60 degrees north and stretched as far as 82 degrees north. Named Operation Arctic Lynx (OAL), the exercise will take place until June 26, 2021 and involves the U.S Department of Defense, U.S federal agencies, Alaska state and local organizations, the Canadian government, scientific research organizations, and multiple aerospace industry companies.

    During the exercise, Iridium’s broadband, Iridium Certus, Push to Talk (PTT), and Iridium Global Line of Sight are the main technologies being tested, alongside a variety of sensors capable of tracking, environmental monitoring, remote control functions and managing data and image delivery.

    “Iridium’s Arctic and Antarctic communications capabilities have long been a part of the fabric of government, NGO and civil enterprise activities in those regions and now with our upgraded constellation and new technologies developed, we have turbocharged our portfolio of solutions to address an increasing range of polar communication requirements,” said Scheimreif.

    “With more than 20 participating organizations, Operation Arctic Lynx will exercise the ability to provide real-time interoperability, communications-on-the-move, command-and-control and develop and maintain a common operational picture in austere polar regions. We’re proud to have so many esteemed organizations participating.”

    During the operation, multiple voice, data, video and real-time communications threads will be exercised, starting from Utqiagvik, Alaska, located at 71 degrees north latitude, although the communication links will also be tested at a site even further north.

    Located 82 degrees north is the Canadian Forces Station Alert in Nunavut, Canada. It is the most northerly, permanently inhabited location in the world and one of a number of Arctic Weather Stations. Here, Iridium Certus technology will be tested to ensure reliable communications.

    Teams utilizing Iridium satellite communications systems in the Arctic as part of Operation Arctic Lynx – via Iridium

    Additional communication tests sites include the U.S South Pole Station and McMurdo Station in Antarctica, Oslo, Norway, London, U.K., and in the U.S. states of Texas, Arizona, Virginia and Florida.

    Iridium’s newest broadband service: Certus 200

    On June 22, Iridium announced their newest service, named Certus 200. It offers transmission speeds up to 176 Kbps and high-quality voice lines though a cost-effective antenna. This service is available for land-based and maritime applications using the terminals built by Thales. Iridium is also looking to offer aviation services, featuring L-band antennas and lightweight terminals. This system is currently under development and is expected to be operational in late 2021.

    “Iridium Certus is a powerful connectivity platform, providing the flexibility for our partners to develop specialized terminals that enhance different capabilities across all industries,” says Bryan Hartin, executive vice president, sales and marketing, Iridium. “Iridium Certus 200 fills an important gap in our broadband portfolio, offering a more affordable product and service class, with reliable connectivity that will expand to more markets.”

    The post Iridium wins contract to develop hosted payload for Low Earth Orbit appeared first on NASASpaceFlight.com.

    Source : NASA More   

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