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<\/p>\nNASA management updated the agency\u2019s human exploration plans for the 2020s to the NASA Advisory Council\u2019s (NAC) Human Exploration and Operations (HEO) Committee last month at the Ames Research Center in California. The focus of the evolving plans for the next decade is launch, assembly, and operations of a human-tended space station in high lunar orbit.\n<\/p>\n
Separate modules of the lunar gateway are planned to be launched to the Moon beginning in 2022, and NASA provided the latest look at the pieces and a forecast of their launch schedule. A commitment of funding for the gateway project is still forthcoming, but the Power and Propulsion Element (PPE) is the module that would launch first.<\/p>\n
NASA plans to award contracts to one or more of the commercial bidders early next year to build, launch, and demonstrate an electric propulsion spacecraft that meets requirements for a Gateway PPE. After a one-year demonstration period, NASA would then exercise a contract option to take over control of the spacecraft.<\/p>\n
New name, new modules<\/p>\n
Now just referred to as \u201cThe Gateway,\u201d the spacecraft formerly known as the \u201cDeep Space Gateway\u201d and referred to in this year\u2019s budget request as the \u201cLunar Orbital Platform \u2013 Gateway\u201d (LOP-G) is planned to orbit high above the poles of the Moon in support of crew visits and science experiments. The plan briefed to the HEO committee last week updated earlier initial looks at the Gateway\u2019s specifications.<\/p>\n
When assembled, the lunar outpost would support Orion missions of between one and three months from launch to splashdown. Month-long missions could be supported initially and that is being looked at now for the first crew visit on Orion to dock to the PPE on Exploration Mission-3 (EM-3).<\/p>\n
\u201cOur very first flight to the Gateway we expect to have an expedition length of about 30 days from launch to landing,\u201d Jason Crusan, Advanced Exploration Systems Director and Gateway Formulation Lead for NASA, said. \u201cWe have a twenty-some day capacity on Orion [and] we have the ability to be on Gateway.\u201d<\/p>\n
\u201cAs we get into the mission design we\u2019ll figure out the total length, but we\u2019ll have the full duration Orion plus anywhere from six to thirteen days on the actual Gateway on the very first mission.\u201d<\/p>\n
<\/p>\n
Orion and crew with the ESPRIT and Utilization modules attached approach the PPE in lunar orbit on EM-3. As with the ISS, the space station will be the passive vehicle for rendezvous and docking and the visiting vehicle (Orion) will be active. Credit: Nathan Koga for NSF\/L2.<\/p>\n
The basic elements of the proposed lunar space station were the PPE, a crew habitation module, an airlock for extra vehicular activity (EVA), and support for logistics supplies that would be launched from Earth. The latest look now has two additional modules that would follow the PPE to the Moon on EM-3, a European System Providing Refuelling, Infrastructure and Telecommunications (ESPRIT) module and an American-provided Utilization module.<\/p>\n
\u201cThat\u2019s our first launch package that goes up to the Gateway,\u201d Crusan said. \u201c[ESPRIT] provides augmentation for additional fuel capacity [and] it actually adds a scientific airlock.\u201d<\/p>\n
\u201cSo the ability to move payloads internal to external is there on the very first pressurized volume that we add. That was actually a very conscious choice in order to enable very early science. We will a number of payload attachment locations on the outside of the Gateway for that.\u201d<\/p>\n
\u201cThe other half of that launch package is a small pressurized volume,\u201d he added. \u201cThat pressurized volume will enable a crew ingress on the very first mission to the Gateway assembly sequence.\u201d<\/p>\n
\u201cIt will add that volume, some consumables and on the very first mission crews will be able to extend their stay in cislunar space with Orion and the utilization module enabling that.\u201d<\/p>\n
The ESPRIT and Utilization modules would launch together with Orion and crew on EM-3; following launch on a Space Launch System (SLS) rocket, Orion would dock to the modules that rode underneath it inside the SLS upper stage, then rendezvous with the PPE in lunar orbit and dock them, adding them to the Gateway.<\/p>\n
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<\/p>\n
Slide from one of the presentations to the NAC HEO committee showing currently defined Gateway modules. The SLS launch date for the Early Operational Capability was said in the meeting to be 2024. Credit: NASA.<\/p>\n
The Gateway is also now expected to need two habitation modules rather than one, as the earlier minimum of 55 cubic meters of habitable volume wouldn\u2019t meet the requirements developed between NASA and several of its international partners working on the International Space Station (ISS).<\/p>\n
\u201cOne of the things in our analysis, both with our U.S. industry and our international partners, the Hab volume that we had originally\u2026didn\u2019t quite meet what we needed to get there as far as the crew health and other accommodations we have there. So we expanded that to the two Habs in concert providing that overall function; this also increased the internal space for biological-type research that folks would like to do there.\u201d<\/p>\n
The two Hab modules, one provided by the United States and one provided internationally, would now provide at least 125 cubic meters of habitable volume. Those would be launched with Orion on separate SLS flights following the ESPRIT and Utilization modules on EM-3.<\/p>\n
Updated launch sequence<\/p>\n
The new elements and new developments in NASA\u2019s Human Exploration divisions are reflected in the current schedule and sequence of launches now planned to begin in 2020. NASA is developing the Orion spacecraft to fly crews back and forth between cislunar space where the Gateway would orbit the Moon and Earth and the SLS rocket to launch it.<\/p>\n
Both were already integral to plans for launch and assembly of the Gateway, but both still must fly integrated for the first time before being applied to those uses. In addition, the unexpected government commitment to and initial funding of a second Mobile Launcher (ML-2) to launch SLS rockets in late March also changed the baselined sequence of launches and their schedule.<\/p>\n
The presentations to the NAC HEO committee show Exploration Mission-1 (EM-1) and Exploration Mission-2 (EM-2) as the first two missions, launching in 2020 and 2022, respectively. Both of those missions are test flights for Orion and SLS; the first mission will fly uncrewed in a Distant Retrograde Orbit (DRO) and the second test flight will take the first Orion crew on a Lunar flyby.<\/p>\n
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<\/p>\n
Slide from a presentation to a joint meeting of the NAC HEO and Science committees in August showing the current schedule outline of human exploration and commercial lunar payload missions. Credit: NASA.<\/p>\n
Altogether the first three SLS launches would fly on the Block 1 vehicle, the two Orion test mission launches and the launch of the Europa Clipper probe directly to Jupiter. Although U.S. federal appropriations bills enacted into law for the last three fiscal years mandate a Europa Clipper launch on SLS and \u201cno later than 2022,\u201d the presentations to the HEO committee show that launch on a Block 1 Cargo vehicle in 2023.<\/p>\n
Both the crewed Orion configuration that will first fly on EM-2 and Europa Clipper are still in development, so it remains to be seen how future engineering and political developments could influence the timing of those launches \u2014 and in the case of Europa Clipper, the launch vehicle.<\/p>\n
While Orion and SLS are flying their test flights, the first Gateway launch is planned in the last half of 2022 with a U.S. commercial launch vehicle placing the PPE on a trajectory towards the Moon. The PPE will perform its own insertion into lunar orbit and its commercial developer would then spend most of 2023 demonstrating the spacecraft\u2019s capabilities to NASA.<\/p>\n
The ESPRIT and Utilization modules would then fly with Orion and crew on EM-3 in 2024, which would be the debut of ML-2 and the SLS Block 1B vehicle with the larger Exploration Upper Stage (EUS). Although NASA indicated there weren\u2019t any notional masses for the modules, the initial SLS Block 1B launch is expected to be able to place both the 25-metric ton Orion spacecraft and several metric tons of secondary, \u201cco-manifested\u201d payloads on a trans lunar injection (TLI) trajectory.<\/p>\n
\u201cOur initial TLI capability we\u2019re targeting nine metric tons (co-manifested payload) on the first one because we\u2019re holding some margin, but after that we\u2019ll do ten metric tons,\u201d Exploration Systems Development (ESD) Deputy Associate Administrator Bill Hill said during one of the presentations to the HEO committee. The habitation modules would then follow one at a time on EM-4 and EM-5.<\/p>\n
PPE award(s) next year if funding approved<\/p>\n
The final Broad Agency Announcement (BAA) solicitation for the PPE, \u201cSpacecraft Demonstration of a Power and Propulsion Element,\u201d was released by NASA on September 6. Originally released for comments in draft form in July, the solicitation defines a set of NASA unique requirements that the spacecraft must meet, but the BAA is intended to allow bidders to use as much off the shelf technology as possible.<\/p>\n
\u201cWe believe can basically use a commercial satellite bus augmented with electric propulsion to meet our needs,\u201d Bill Gerstenmaier, NASA Associate Administrator for the Human Exploration and Operations Directorate (HEOMD), said. \u201cSo we don\u2019t need a unique spacecraft design, we don\u2019t need a unique bus, we believe what\u2019s available in industry can be used with augmentation of the solar electric propulsion, and that\u2019s what we\u2019ll find out with this BAA activity.\u201d<\/p>\n
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<\/p>\n
Artist concept of PPE in lunar orbit. Credit: NASA.<\/p>\n
The main technology development to be integrated into the spacecraft is a solar electric propulsion (SEP) system. The final BAA requirements state: \u201cThe PPE Flight System shall utilize an electric propulsion system with the capability to operate over a thrust-to-power ratio range of at least 43 \u2013 52 mN\/kW (millinewtons per kilowatt).\u201d<\/p>\n
The final BAA set a deadline for bidders to submit proposals of November 15. \u201cNASA and its PPE partner(s) will begin the project upon contract award, which is targeted for March 2019 (TBD), and conclude 24 months after the successful spaceflight demonstration if all of the options are executed,\u201d the final BAA adds.<\/p>\n
\u201cThe Offeror shall propose a schedule with a launch date no later than September 2022 with a demonstration to last no longer than one year in duration to be completed no later than September 2023.\u201d<\/p>\n
An award or awards of firm, fixed price contracts are currently anticipated to be announced next March; however, the timing and nature of the initial announcements are contingent on the outcome of the Fiscal Year 2019 federal government budget process. The gateway was a \u201cnew start\u201d in the FY 2019 budget request submitted by the Trump Administration in February; the project must receive enacted language that includes the authority to proceed and also enacted appropriations before efforts can proceed beyond studies.<\/p>\n
Appropriations committees in both houses of Congress have approved bills for FY 2019 providing that authority and $504.0 mission for the Gateway, but neither bill for \u201cCommerce, Justice, Science, and Related Agencies\u201d has been voted on by the full House of Representatives and Senate. In recent years few of these bills have come to the floor of either chamber to be voted on by the time a fiscal year begins on October 1; instead, a series of \u201cContinuing Resolutions\u201d (CR) are passed until a compromise is agreed on or in a few cases, the fiscal year ends.<\/p>\n
Continuing Resolutions only fund programs previously authorized, which wouldn\u2019t include the Gateway as a project or the PPE specifically.<\/p>\n
\u201cNASA may not make any awards to those selected until NASA receives the fiscal year 2019 appropriations or may choose to only award a portion of those selected and reserve the remaining awards pending the final appropriations for the fiscal year,\u201d the final BAA notes. \u201cAny reduced appropriations or continuing resolution may affect NASA\u2019s ability to award selected Offerors.\u201d<\/p>\n
PPE requirements<\/p>\n
High-level PPE requirements are for the spacecraft to have a 15-year on-orbit operational lifetime, beginning at separation from the launch vehicle. The PPE will include both SEP and chemical propulsion systems, with the latter being based on monopropellant hydrazine.<\/p>\n
The PPE is the core element of the Gateway. \u201cIt will provide transportation for the LOP-G between cislunar orbits with the option to perform any needed orbital maintenance,\u201d the FY 2019 budget request stated. \u201cIt will provide attitude control for the LOP-G in multiple configurations, communication to and from Earth, space-to-space communication, space-to-lunar communication, and in support of astronaut EVA. PPE will also deliver systems necessary for deep space navigation, docking, and refueling. At the end of the LOP-G operational life, PPE will move the integrated LOP-G stack to a disposal orbit.\u201d<\/p>\n
Awardees will spend up to a year after launch demonstrating that the spacecraft meets the different requirements.<\/p>\n
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<\/p>\n
Slide from an August presentation to the NAC HEO committee outlining the planned Gateway orbit. The most recent indication was that an L2 Southern NRHO was current choice. Credit: NASA.<\/p>\n
Operationally, the requirements are for the PPE spacecraft to fly itself from its trajectory at the time of separation from the launch vehicle into lunar orbit: \u201cThe PPE Flight System shall utilize the Ion Propulsion System for orbit insertion into the Near Rectilinear Halo Orbit,\u201d the final BAA requirements say. \u201cChemical propulsion may be used in combination with SEP.\u201d<\/p>\n
\u201cIn looking at different orbits to put the Gateway in, there\u2019s been a lot of discussion of low lunar orbits, distant retrograde orbits, halo orbits of different families \u2014 L1, L2-type orbits,\u201d Crusan said. \u201cThe orbit that we\u2019re putting Gateway nominally in to begin with is what we call a near rectilinear halo orbit, likely optimized for the South Pole.\u201d<\/p>\n
L1 and L2 refer to two of the Lagrangian points in the Earth-Moon system. \u201cThere\u2019s different families of different orbits,\u201d he added. \u201cYou can bias them with an L1 bias or an L2 bias and you can do a North and South version of those as well. We are optimizing for the South because we believe that\u2019s a more target rich areas for surface activities as well.\u201d<\/p>\n
The PPE is required to be in the NRHO chosen for Gateway one year after launch. Its fuel load is sized to meet requirements based on overall operating expectations over its lifetime.<\/p>\n
![\"\"](\"https:\/\/www.nasaspaceflight.com\/wp-content\/uploads\/2018\/09\/ppe_nac_heo.PPE-Overview.Page-7.jpg\")
<\/p>\n
Presentation slide to the NAC HEO committee outlining the PPE. Credit: NASA.<\/p>\n
\u201cWe have enough propellant in the Power Prop Element to handle orbital maintenance for fifteen years and two large maneuvers, the most pressing case maneuvers of the entire Gateway stack back and forth, we have that all in the Power Prop Element,\u201d Crusan noted. \u201cThe ESPRIT capability will actually increase our overall propellant capacity and could be as high as doubling that before we need our first refuel; but we will be able to refuel if we wanted to move it around more often.\u201d<\/p>\n
The requirements indicate maintenance of the NRHO chosen for the Gateway are relatively low: \u201cThe PPE Flight System shall conduct orbit maintenance maneuvers in the Near Rectilinear Halo Orbit with a maximum magnitude of less than 10 m\/s of delta-v per year.\u201d<\/p>\n
Following the demonstration period when NASA would exercise the option to assume ownership of the spacecraft, the PPE mass is required not to exceed 8000 kg, including a minimum of 1050 kg of Xenon for SEP and 800 kg of hydrazine for the Reaction Control System (RCS). The Xenon tank in the PPE is required to have a minimum capacity of 2000 kg, and both the Xenon and hydrazine propellant tanks will have the capability to be refueled.<\/p>\n
Commercial cargo resupply<\/p>\n
One of the factors that went into consideration for choosing a target lunar orbit for the Gateway was access by U.S. commercial launch services. \u201cIn the orbit that we\u2019re picking we\u2019re looking at an optimization of where we know we can fly with our Orion and our SLS vehicles, but also equally as important [is] where do we stage it [for] commercial launch vehicles doing cargo, as well,\u201d Crusan said.<\/p>\n
\u201cOur minimum that we want to be able to deliver logistics-wise [is] at least three to four metric tons per delivery; the NRHO orbit is optimized for commercial industry delivery in addition to fly Orion and SLS there.\u201d<\/p>\n
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<\/p>\n
One of the presentation slides highlighted four different U.S. commercial launch vehicles. The Falcon 9 (left) is the only one currently in service, followed by Blue Origin\u2019s New Glenn, ULA\u2019s Vulcan, and Northrop Grumman\u2019s OmegA vehicles that are currently in development. Credit: NASA.<\/p>\n
The SpaceX Falcon Heavy that began flying in February and Blue Origin\u2019s New Glenn under development were noted as launchers that can deliver large enough resupply packages to the Gateway. \u201cCommercial launch vehicle performance to TLI is predicted, so Falcon Heavy, New Glenn, and those types of rockets, are in the family of anywhere from eleven to fourteen metric tons of TLI performance; for SLS it\u2019s about thirty-four,\u201d Crusan added.<\/p>\n
\u201cYou take the anywhere from twelve to fourteen metric tons of TLI performance, the logistics vehicle, so [the] pressurized volume and service module to deliver it, and you have the payload that sits inside of it much like Commercial Resupply Services does for us today in ISS (International Space Station) and you end up with about a three to four metric ton of available payload, pressurized payload to NRHO,\u201d he explained.<\/p>\n
Existing U.S. launchers such as United Launch Alliance\u2019s Atlas V and Delta IV Heavy could also provide some of these services, but they may be phased out in the 2020s by the Vulcan launcher they are developing. Notionally, one of presentation slides shows Falcon, New Glenn, Vulcan, and the OmegA launcher being developed by Northrop Grumman Innovation Systems (NGIS \u2013 formerly Orbital ATK).<\/p>\n","protected":false},"excerpt":{"rendered":"
NASA management updated the agency\u2019s human exploration plans for the 2020s to the NASA Advisory Council\u2019s (NAC) Human Exploration and Operations (HEO) Committee last month at the Ames Research Center in California. The focus of the evolving plans for the next decade is launch, assembly, and operations of a human-tended space station in high lunar […]<\/p>\n","protected":false},"author":1,"featured_media":0,"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":[8909,419,640,624],"class_list":["post-38300","post","type-post","status-publish","format-standard","hentry","category-news","tag-em-3","tag-gateway","tag-orion","tag-sls"],"acf":[],"_links":{"self":[{"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/posts\/38300"}],"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=38300"}],"version-history":[{"count":0,"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/posts\/38300\/revisions"}],"wp:attachment":[{"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/media?parent=38300"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/categories?post=38300"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/tags?post=38300"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}