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If Discovery were to launch on the 24th February, then under current plans, Discovery and ATV-2 would be docking to the ISS on the same date \u2013 26th February. This is not doable due to the amount of work that would be placed on the ISS crew.<\/p>\n
As such, the ISS Program (ISSP) is currently in discussions with the European Space Agency (ESA) with a view to eliminating the three extra days from ATV-2\u2019s free flight, which would allow ATV-2 to dock on 23rd February, instead of the currently planned 26th. Should this agreement be made, this would allow Discovery to launch on the 24th \u2013 one day after ATV-2\u2019s docking.<\/p>\n
![\"\"](\"https:\/\/www.nasaspaceflight.com\/wp-content\/uploads\/2011\/01\/A35.jpg\" "\\"A3\\"")
The major issue with this plan is that if ATV-2\u2019s launch is scrubbed by one day, then Discovery\u2019s launch will also need to be delayed by one day, due to the fact that the three extra days have been removed from ATV-2\u2019s free flight, and so no time exists in the free flight for launch slippage.<\/p>\nIf no agreement can be made, Discovery will launch on February 27th \u2013 one day after ATV-2\u2019s docking.<\/p>\n
Discovery\u2019s launch slip has also affected the robotics operations for HTV-2, currently planned to launch on 20th January, for a rendezvous and berthing to the ISS on 27th January. The launch window, however, extends from the 20th to the 28th January, with launch attempts to be made every three days.<\/p>\n
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HTV-2 will be a challenging mission from a robotics perspective, with multiple operations planned that include use of the Space Station Remote Manipulator System (SSRMS) \u201cCandarm2\u201d, the Special Purpose Dextrous Manipulator (SPDM) \u201cDextre\u201d, the Mobile Base System (MBS), the Mobile Transporter (MT), and the Japanese Experiment Module Remote Manipulator System (JEM RMS).<\/p>\n
ISS Specific Articles: http:\/\/www.nasaspaceflight.com\/tag\/ISS\/<\/p>\n
![\"\"](\"https:\/\/www.nasaspaceflight.com\/wp-content\/uploads\/2011\/01\/A331.jpg\" "\\"A331\\"")
Shuttle Discovery is dictating the robotics operations due to the fact that she is carrying the ExPrESS [Expedite the Processing of Experiments to Space Station] Logistics Carrier-4 (ELC-4) in her Payload Bay (PLB), which is the install site for both of HTV-2\u2019s external Orbital Replacement Unit (ORU) payloads \u2013 the Flex Hose Rotary Coupler (FHRC) and Cargo Transportation Container-4 (CTC-4).<\/p>\nDue to the fact that Discovery\u2019s launch date has been pushed into the late February window, there will now be insufficient time to complete all ORU transfers to the ISS prior to HTV-2\u2019s departure date on 28th March. If STS-133\u2019s launch date is pushed beyond the late February window, then both ORUs will have no install location on ISS prior to HTV-2\u2019s departure.<\/p>\n
A full overview of HTV-2 robotics operations was detailed in an expansive set of HTV-2 Mission Operations Directorate (MOD) Flight Readiness Review (FRR) documents, available to download on L2.<\/p>\n
![\"\"](\"https:\/\/www.nasaspaceflight.com\/wp-content\/uploads\/2011\/01\/A74.jpg\" "\\"A74\\"")
On HTV-2 Flight Day-7 (FD-7), the HTV will be captured and berthed to the Node 2 Nadir Common Berthing Mechanism (CBM) by the SSRMS, which will be based on the Node 2 Power and Data Grapple Fixture (PDGF).<\/p>\nA few hours after the berthing, the SSRMS will grapple the Exposed Pallet (EP) in HTV-2\u2019s Unpressurised Logistics Carrier (ULC), in order to provide power to the EP\u2019s two ORU payloads.<\/p>\n
A few days after the berthing, the SSRMS will extract the EP from HTV-2\u2019s ULC and hand it off to the JEM RMS. The JEM RMS will then attach the EP to the Japanese Exposed Facility (JEF) via the JEF\u2019s Exposed Facility Unit (EFU), and the EP\u2019s Payload Interface Unit (PIU).<\/p>\n
When connected together, the EFU and PIU become an Equipment Exchange Unit (EEU).<\/p>\n
![\"\"](\"https:\/\/www.nasaspaceflight.com\/wp-content\/uploads\/2011\/01\/a212.jpg\" "\\"a212\\"")
A few days later, the SSRMS will retrieve the SPDM from MBS PDGF number 2. The SPDM, on the end of the SSRMS, will then retrieve the FHRC and CTC-4 from the EP on the JEF.<\/p>\nTwo plans are being considered that would either place both ORUs on the SPDM\u2019s Enhanced ORU Temporary Platform (EOTP), which was delivered during STS-132 last May, or one ORU on the EOTP and another on one of the SPDM\u2019s \u201carms\u201d, which may better distribute the heater power draw of the two ORUs.<\/p>\n
The SPDM will then be placed on the MBS. Having ORUs on the SPDM during STS-133 may carry some issues, however, as one of STS-133\u2019s EVA tasks is to install a CLPA lens cover over the SPDM\u2019s video camera.<\/p>\n
In the days following the ORU transfers to the SPDM, the JEM RMS will grapple and remove the EP from the JEF, and hand it off to the SSRMS. The SSRMS will then re-insert the empty EP into the ULC.<\/p>\n
This plan ensures that both ORUs are transferred to ISS and the EP re-inserted into the ULC before HTV-2 has to depart the station.<\/p>\n
![\"\"](\"https:\/\/www.nasaspaceflight.com\/wp-content\/uploads\/2011\/01\/HT5.jpg\" "\\"HT5\\"")
The next task for the SSRMS, still based on the Node 2 PDGF, will be to grapple HTV-2 and relocate it from the Node 2 Nadir CBM to the Node 2 Zenith CBM. The relocation is a Launch Commit Criteria (LCC) for STS-133, as HTV-2 would preclude payloads from being removed from Discovery\u2019s PLB if it were berthed to Node 2 Nadir.<\/p>\nThis means that Discovery cannot launch until the relocation has been performed, due to the fact that, should a problem arise during HTV-2\u2019s unberthing from the ISS, Discovery would be unable to perform her mission objectives of installing the Permanent Multipurpose Module (PMM) and ELC-4 onto the ISS.<\/p>\n
The Mobile Servicing System (MSS), which includes the Mobile Transporter, MBS, SSRMS, and SPDM, will then be reconfigured to support the STS-133 mission. All of the aforementioned operations are time-critical, as they must be completed before Discovery launches. If any problems or issues arise during these robotics operations, very little time will exist to perform troubleshooting.<\/p>\n
![\"\"](\"https:\/\/www.nasaspaceflight.com\/wp-content\/uploads\/2011\/01\/A321.jpg\" "\\"A321\\"")
Following the successful installation of ELC-4 onto the S3 Nadir Inboard Payload Attach System (PAS), and Discovery\u2019s departure from the ISS, the SSRMS will position itself on the MBS, and the MT (with MBS attached) will then translate from Worksite 5 (WS-5) to WS-2. The SSRMS will then grapple the SPDM, and the SPDM will install the FHRC and CTC-4 onto ELC-4.<\/p>\nOn the third and final day of the ORU transfer operations, the SSRMS will place the SPDM back onto the MBS, the MT will translate from WS-2 to WS-5, and the SSRMS will then be relocated to the Node 2 PDGF.<\/p>\n
It is unclear at this time as to whether HTV-2 will be relocated back to Node 2 Nadir prior to unberthing. Whichever option is chosen, the final task for the SSRMS will be to unberth HTV-2 from Node 2 Nadir or Zenith, and release it to free-fly once again.<\/p>\n
(Images used: Lead \u2013 NASA.gov. Within the article \u2013 via L2 presentations).<\/p>\n","protected":false},"excerpt":{"rendered":"
Following the further delay of the STS-133\/ULF-5 mission into late February, International Space Station (ISS) Program Managers are readjusting the mission plans for Europe\u2019s Automated Transfer Vehicle-2 (ATV-2) \u201cJohannes Kepler\u201d and Japan\u2019s H-II Transfer Vehicle-2 (HTV-2) \u201cKounotori\u201d. Both vehicles will be present at the ISS during the STS-133 mission, which should provide for some stunning […]<\/p>\n","protected":false},"author":1,"featured_media":29523,"comment_status":"","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"inline_featured_image":false,"footnotes":"","_links_to":"","_links_to_target":""},"categories":[2],"tags":[4140,1839,233,9051],"class_list":["post-40558","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-news","tag-atv","tag-htv","tag-iss","tag-sts-133"],"acf":[],"_links":{"self":[{"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/posts\/40558"}],"collection":[{"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/comments?post=40558"}],"version-history":[{"count":0,"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/posts\/40558\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/media\/29523"}],"wp:attachment":[{"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/media?parent=40558"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/categories?post=40558"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/tags?post=40558"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}