Chinese Long March 2D carries Tianhui survey satellite into orbit

A Chinese Long March 2D rocket lifted off from the Jiuquan Satellite Launch Center in… The post Chinese Long March 2D carries Tianhui survey satellite into orbit appeared first on NASASpaceFlight.com.

Chinese Long March 2D carries Tianhui survey satellite into orbit

A Chinese Long March 2D rocket lifted off from the Jiuquan Satellite Launch Center in Inner Mongolia at 04:01 UTC today, July 29, carrying Tianhui 1-04, the fourth in China’s series of Tianhui 1 Earth observation satellites, into Low Earth Orbit.

The launch marked the 25th orbital launch attempt from China this year and the sixth in the month of July.

The Long March 2D‘s four YF-21C engines ignited shortly before liftoff, providing the launch vehicle with 2,962 kN of thrust, allowing the carrier rocket to loft the approximately 1,000 kg satellite into a 97.3 degree inclined Sun-Synchronous Orbit, around 490 to 500 kilometers above the surface of the Earth.

The liftoff marks the 381st launch of a Long March series rocket, and the 54th mission using a Long March 2D, which has seen an illustrious career having seen regular service since 1992 and only one partial failure in 2009.

Long March 2D carrying Tianhui1-04. seconds prior to liftoff – via China Daily

The Tianhui 1 series of satellites, which first began launching in 2010 with the launch of Tianhui 1-01, are a set of topographical mapping satellites built by Aerospace Dongfanghong Satellite Company, a subsidiary of the Chinese Academy of Space Technology (CAST).

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  • CAST is itself a subordinate of the China Aerospace Science and Technology Corporation (CASC), which operates China’s Long March family of rockets. The Long March launchers are also known by Chang Zheng in China.

    Literally translating to “Sky Drawing,” the Tianhui series of spacecraft are built for remote sensing and Earth observation roles on behalf of the Chinese government. The program began development in 2005, and began operation five years later with the launch of Tianhui 1-01.

    Tianhui 1-02 and 1-03, the second and third spacecraft in the series, were launched in 2012 and 2015 respectively. The three previous Tianhui spacecraft, like 1-04, were also launched aboard Long March 2D vehicles.

    Each spacecraft is built off of the CSAT2000 spacecraft bus and is equipped with a number of electro-optical sensors to facilitate it’s mission.

    Like it’s three predecessors, Tianhui 1-04 is equipped with three separate Earth observation cameras: a three-line array panchromatic camera with a spatial resolution of five meters, a panchromatic CCD camera with a spatial resolution of two meters, and a multi-spectral imager with a spatial resolution of 10 meters.

    The CSAT2000 based VRSS-2 spacecraft prior to launch in 2017 – via CAST

    The spacecraft is also fitted with three star-sensors in order to keep the spacecraft stable for long periods of time while it observes Earth’s surface.

    The CAST2000 bus is specifically made for remote sensing satellites, featuring an S-band Telemetry Tracking and Control (TT&C) sub-system and X-band data transmission sub-system communications systems, as well as its three aforementioned star sensors which provide three-axis stabilization in order to keep the spacecraft stable when conducting observations.

    The bus has seen large amounts of usage outside of the Tianhui 1 series of satellites, providing the base spacecraft for several other Earth observation programs, including the Indian Space Research Organization’s OceanSat 1A and 1B spacecraft, Venezuela’s VRSS-1 and VRSS-2 remote sensing missions, and China’s Huanjing 1A and 1B disaster and environmental monitoring spacecraft.

    Thursday’s mission lifted off from the SLS-2 pad at the Jiuquan Satellite Launch Center, one of China’s inland launch sites. Missions from Jiuquan, the Xichang Satellite Launch Center, and the Taiyuan Satellite Launch Center all result in rockets overflying populated areas on the way to orbit. This contrasts with the safety norm upheld by the majority of space faring nations, where launches are either conducted over bodies of water or uninhabited desert.

    The Long March 2D is also one of China’s launch vehicles which is fueled by toxic, hypergolic propellants. Both of the rocket’s stages are fueled by Unsymmetrical dimethylhydrazine (UDMH) with Dinitrogen tetroxide oxidizer. This can cause issues when combined with overflight of populated areas, as discarded stages containing carcinogenic fumes can land near civilians.

    The Chinese space program has been slow to transition to their new coastal launch site at the Wenchang Spacecraft Launch Site and their newer launch vehicles fueled by liquid hydrogen or kerosene with liquid oxygen. Experimental attempts to control downrange landing locations of both booster stages and fairings have been made, but no such attempt was incorporated into the launch of Tianhui 1-04.

    (Lead photo via China Daily)

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    MLM Nauka makes triumphant docking to ISS

    Russia’s Multipurpose Laboratory Module (MLM) Nauka, meaning “science,” has defied the odds to successfully dock… The post MLM Nauka makes triumphant docking to ISS appeared first on NASASpaceFlight.com.

    MLM Nauka makes triumphant docking to ISS

    Russia’s Multipurpose Laboratory Module (MLM) Nauka, meaning “science,” has defied the odds to successfully dock to the ISS after a long and arduous journey dating back over 20 years and a problematic propulsion system after launch which had threatened the success of the mission. 

    The docking was not without issue, with Russian cosmonauts noting that Nauka wasn’t on the correct course less than an hour before docking; however, a retro burn quickly corrected the issue. After also troubleshooting an issue with the TORU manual docking system, which was used for the final seconds of the module’s approach, Nauka successfully docked to the Zvezda service module’s nadir port at 09:29 EDT / 13:29 UTC, marking the first major expansion to the Russian segment for over 20 years.

    Nauka docking

    Nauka had been chasing down the International Space Station (ISS) for the last eight days after being launched atop a Proton-M booster from the Baikonur Cosmodrome in Kazakhstan on 21 July.

    Immediately after a successful orbit insertion of 190 x 350.1 km, issues with the module’s communications and propulsion systems were noted. Initial troubleshooting was complicated by limited communications during brief periods when the module came within range of Russian ground stations.

    The communications issues were resolved in initial orbits; however, the propulsion system issue was more troublesome and believed to be related to a part of the module’s fuel supply being rendered unusable due to gases becoming mixed with the fuel for the main engine.

    Reports indicated that pressure in the main engine’s propulsion tanks had risen to unacceptable levels due to an earlier-than-planned equalization of pressure between the tanks. Thus, use of the smaller engines would be needed to relieve tank pressure to a point where the main engine could be used.

    That, coupled with continuous limited communications, resulted in several of the initially-planned orbit raising burns being cancelled and then later conducted using the module’s secondary engines.

    These replanned first burns were enough to prevent Nauka from reentering the atmosphere within a few days, as was the fear given the low perigee insertion of 190 km. With those first burns, Russian controllers were able to stabilize Nauka, get the main engine working, and keep the module on track for a 29 July arrival at the Station as originally planned.

    Approaching the ISS, Nauka used its KURS automated rendezvous system as intended; however, the module was also equipped with a TORU manual docking system, which would have enabled cosmonauts Novitsky and Dubrov aboard the ISS to take control of Nauka and fly it manually if needed.

    For the docking, the ISS was placed in a special attitude – essentially pitched up 90 degrees – in order to place Nauka’s docking axis along the velocity vector. This was not the original plan, which would have seen Nauka approach up the R-bar, or Radial velocity vector, with the nadir Zvezda port facing straight down at Earth.

    The ISS orientation plan for docking was changed to accommodate Nauka’s as-is condition after launch.

    Docking was made to Zvezda’s nadir docking port, which was recently vacated by the Pirs module on 26 July. This port uses a docking system called the Hybrid Drogue Adapter (HDA).

    Nauka, just before encapsulation for launch. (Credit: Roscosmos)

    HDA is a Russian system which is essentially the combination of the traditional Probe & Drogue (SSVP) system and the Androgynous Peripheral Attachment System (APAS), on which the docking system of Dragon and Starliner is now based.

    Specifically, HDA uses the docking collar from the APAS system, but rather than use a capture ring as is the case on the US segment, it instead uses a docking drogue as found on the SSVP system. This enables dockings to occur the same way as they do for Soyuz/Progress vehicles but gives a wider passageway through the hatch, which is useful for permanent modules.

    Following docking and hard capture, the next immediate steps will be leak checks and vestibule pressurization followed by hatch opening, first ingress, and module activation.

    Future plans:

    A total of up to 11 spacewalks will be required in order to fully outfit and commission Nauka, with the first of these set to be performed in September.

    Externally, after the module has been connected to the ISS via a series of cables, the first order of business will be to deploy the European Robotic Arm (ERA), which launched attached to the outside of Nauka.

    This will involve removing external covers and launch restraints, following which the arm will be activated and fully checked out from the ground. ERA needs to be fully operational in order to proceed with the next phase of operations – which is transferring an airlock and radiator to Nauka.

    This radiator and airlock were launched to the ISS attached to the outside of the Mini Research Module-1 (MRM-1) Rassvet on the STS-132 mission in May 2010 by Space Shuttle Atlantis. For the past 11 years, they have waited patiently for the arrival of Nauka.

    The deployable radiator will be used to add additional cooling capability to Nauka, which will enable the module to host more scientific experiments. The airlock will be used only to pass experiments inside and outside the module, with the aid of ERA — very similar to the Japanese airlock on the US segment of the station.

    The ERA will be used to remove the radiator and airlock from MRM-1 and transfer them over to MLM – with an extension boom being required to allow ERA to reach the airlock. This process is expected to take several months. A Portable Work Platform will also be transferred over, which can attach to the end of the ERA to allow cosmonauts to “ride” on the end of the arm during spacewalks.

    Nauka also features a docking port on its nadir which other modules/vehicles can dock to. This port is also of the HDA type (passive side), however it features a special adaptor in order to convert it into a traditional Probe & Drogue port. This adapter converts the APAS docking collar into an SSVP docking collar, which will enable Soyuz and Progress vehicles to dock to MLM.

    An internal cut-way showing the layout of Nauka. (Credit: Roscosmos)

    In November, Russia will launch the Node Module (NM) Prichal to the ISS, which will dock to the nadir port of Nauka and will add a further four HDA-type ports to the Russian Segment for future expansion – although any expansion plans are now somewhat up-in-the-air following Russia’s decision to focus their future efforts on constructing their own station to succeed the ISS, possibly in cooperation with China.

    Prichal will dock to Nauka using the HDA system, which will first require the removal of the HDA-to-SSVP adapter ring from the nadir port of Nauka.

    This ring was therefore added as an “insurance policy” in case Prichal failed to make it to orbit, which would have rendered Nauka’s nadir HDA port useless as Soyuz and Progress vehicles would not have been able to dock to it which would have left the Russian Segment with only three usable docking ports.

    The first docking to Nauka is planned for September 28, when Soyuz MS-18 will be relocated from Rassvet to Nauka’s nadir port in order to clear Rassvet for the arrival of Soyuz MS-19. MS-18 will then depart Nauka on October 17, whereupon Progress MS-17 will be undocked from MRM-2 Poisk and relocated to Nauka on October 27.

    Assuming Prichal is successfully launched on November 24, Progress MS-17 will then undock from Nauka, taking with it the APAS-to-SSVP adapter ring, which will convert Nauka’s nadir port back to HDA configuration ready for the arrival of Prichal.

    The planned configuration of ISS after Nauka and Prichal are attached. (Credit: Roscosmos)

    In future, it will be standard practice to dock Soyuz vehicles to the nadir ports of Rassvet and Prichal and dock Progresses to the aft port of Zvezda and the zenith port of Poisk.

    This is because the transfer chamber which connects to Zvezda’s aft port has a small leak which requires the hatches to remain closed as much as possible, which would block access to a Soyuz if it were docked to Zvezda’s aft port. In addition, Progress crafts are preferred for Zvezda’s aft port as this enables them to perform ISS reboosts using their main engines.

    Progresses are also preferred for the Poisk zenith port as Poisk is now serving as the Russian Segment’s airlock following the departure of Pirs, and access to Soyuz craft docked to Poisk is blocked whilst Poisk is depressurized during spacewalks, which presents safety issues in an ISS evacuation scenario.

    (Lead image: Nauka arriving at ISS. Credit: Mack Crawford for NSF/L2)

    The post MLM Nauka makes triumphant docking to ISS appeared first on NASASpaceFlight.com.

    Source : NASA More   

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