6.09.2020
Rocket limbo complicating NASA's Europa Clipper mission
Clipper team members say they need a decision soon
NASA's Europa Clipper mission, which will study the Jupiter ocean moon Europa in detail, is scheduled to launch in 2024.
NASA's highly anticipated mission to the Jupiter ocean moon Europa needs a rocket — and soon, the project's planners say.
The Europa Clipper probe is scheduled to launch in 2024 to study the Jovian satellite, which harbors a huge sea of liquid water beneath its icy shell. Clipper will assess the habitability of that buried ocean and perform a number of other tasks, including scouting out promising sites for a future life-hunting lander mission.
Congress has long mandated that Clipper launch atop the Space Launch System(SLS), the giant rocket that NASA is developing to send astronauts toward the moon and other distant destinations. But SLS has been plagued by delays and cost overruns, and the megarocket isn't slated to debut until late 2021.
That initial mission will launch NASA's Orion capsule on an uncrewed flight around the moon for the space agency's Artemis program of lunar exploration. SLS and Orion are key elements of Artemis, which seeks to land two astronauts near the moon's south pole in 2024 and establish a sustainable human presence on and around Earth's nearest neighbor by the end of the decade.
Given the commitment to Artemis and the relatively slow pace of SLS development, the rocket's availability for an on-time Europa Clipper launch is in serious doubt, NASA's Office of Inspector General concluded last year.
This concern has apparently bubbled up into the U.S. House of Representatives. The House's proposed 2021 NASA budget, which was released in July, directs the agency to launch Clipper by 2025 and the Europa lander by 2027. The proposal dictates that SLS be used for both missions "if available." That wording leaves the door open for a commercial alternative — perhaps SpaceX's Falcon Heavy, the operational rocket that comes closest to SLS' power (though SLS' power remains purely hypothetical until it flies).
The Europa Clipper team has been planning for both launch contingencies. But the mission cannot stay in this limbo for much longer, team members said.
"We really need a decision by the end of this calendar year in order to continue to mature the spacecraft development," Europa Clipper project manager Jan Chodas, of NASA's Jet Propulsion Laboratory in Southern California, said on Wednesday (Sept. 2) during the fall meeting of NASA's Outer Planets Assessment Group.
The mission team is already working toward a big milestone at the end of the year: Clipper's critical design review (CDR), the final vetting hurdle to clear before full-scale manufacturing begins, will be held in December.
The CDR "was originally planned to be earlier, but, because of the launch-vehicle uncertainty, we've delayed it until the end of the year," Chodas said.
The roughly $3 billion Europa Clipper mission has been dealing with other complications as well. Costs have ballooned on several science instruments, for example. And the coronavirus pandemic has had a significant impact, the extent of which is still being assessed, Chodas said.
The team is aiming to have Clipper launch-ready in early 2024. Liftoff will occur in summer or fall of that year, if all goes according to plan.
Clipper will eventually settle into orbit around Jupiter. The probe will study Europa in depth during a series of roughly 50 flybys, which will take place over nearly four Earth years. Clipper will use nine science instruments to characterize Europa's ocean, measure the thickness of the moon's ice shell and hunt for plumes of water vapor wafting from the surface, among other tasks. The probe will also look for good touchdown sites for the Europa lander, which is still a concept mission, not an official NASA project.
Quelle: SC
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Update: 5.12.2020
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White House asks Congress to remove Europa Clipper SLS requirement
WASHINGTON — The White House is asking Congress to remove language from an appropriations bill that would direct NASA to launch the Europa Clipper mission on the Space Launch System as a long-running dispute on how to launch the mission nears its conclusion.
In a Nov. 30 letter to Sen. Richard Shelby (R-Ala.), chairman of the Senate Appropriations Committee, Russell Vought, director of the White House Office of Management and Budget (OMB), discussed issues his office had with a series of fiscal year 2021 spending bills Shelby’s committee released Nov. 10. Those bills were intended to serve as the starting point in negotiations with the House, which passed its version of those bills in the summer.
Those Senate bills included a commerce, justice and science spending bill that provides NASA with $23.5 billion in 2021. The bill included language found in previous years’ bills, but not the House version for 2021, that NASA “shall use the Space Launch System as the launch vehicle for the Jupiter Europa Clipper mission.”
“The Administration is disappointed that the bill would require NASA to use the Space Launch System (SLS) rocket to launch the Europa Clipper mission,” Vought wrote in his letter to Shelby. “This would increase costs for the Clipper mission and deprive the lunar exploration effort of a rocket NASA needs for human exploration of the Moon.”
In the last few years, NASA has sought launching Europa Clipper on a commercial launch vehicle, like the Falcon Heavy, rather than the SLS. The agency argued that it needed initial SLS vehicles for its Artemis lunar exploration program, and that using a commercial alternative could save up to $1.5 billion.
The House provided some relief to NASA in its spending bill in July. “The Committee believes that the Clipper mission should use a vehicle to support a launch to reduce overall mission costs and complexity and expedite science results in concert with the decadal survey,” House appropriators stated in a report accompanying their spending bill.
Senate appropriators didn’t explain why they retained the SLS language in their bill. They took an unorthodox approach to the fiscal year 2021 spending bills, holding no subcommittee or full committee markups of legislation, instead releasing drafts more than a month after the 2021 fiscal year started Oct. 1.
From a technical standpoint, SLS has long been the preferred choice for Europa Clipper, since it allows the spacecraft to fly to Jupiter on a direct trajectory, arriving less than three years after launch. Alternative vehicles would instead rely on gravity assist flybys to get Europa Clipper, adding years to the travel time.
However, agency officials said in August they were studying “potential hardware compatibility issues” between the Europa Clipper spacecraft and the SLS. NASA did not elaborate on those problems, but said that “special hardware adjustments” may be needed to address them.
Potential changes to the Artemis program could address one problem about using SLS for launching Europa Clipper. While the incoming Biden administration has not talked about space policy, campaign statements such as the Democratic Party platform released this summer suggest it may at least slow the pace of returning humans to the moon, eliminating the 2024 goal established by the Trump administration. That could free up an SLS vehicle for a Europa Clipper launch in 2024, the mission’s current launch readiness date.
House and Senate appropriators are in negotiations on a final set of 2021 spending bills. The federal government is currently operating under a continuing resolution that expires Dec. 11.
Whatever language in in that final bill could mark the end of a years-long debate on how to launch Europa Clipper. Project officials said this summer that they want to make a final decision on the launch vehicle by the time of the mission’s critical design review, scheduled for December. Postponing that decision would increase the mission’s costs as they continue to support analyses for both SLS and a commercial alternative.
The OMB letter criticizes other aspects of the Senate legislation regarding NASA, including the $1 billion provided for the Human Landing System program, far short of the $3.2 billion requested to keep a 2024 landing on schedule. The letter also noted the “under-funding” of NASA’s low Earth orbit (LEO) commercialization efforts, which received only $15 million in the Senate bill versus the $150 million in the agency’s request. That reduced funding, the letter warned, “risks leaving the Nation without a presence in LEO when the International Space Station is eventually retired.”
However, OMB praised the Senate for providing $11.8 million for the Office of Space Commerce within the Department of Commerce. The administration sought $15 million for the office in its 2021 request, far above the $2.3 million it received in 2020, in order to implement Space Policy Directive 3 regarding space traffic management. The House did provide any additional money for the office, stating that it was waiting for a report by the National Academy of Public Administration on which agency should lead civil space traffic management work. That report, released in August, endorsed the Commerce Department as the lead agency for that activity.
“The Administration looks forward to continued engagement with the Congress as these efforts progress and it continues to urge the Congress to support the transfer of the Office of Space Commerce from the National Oceanic and Atmospheric Administration (NOAA) to the Office of the Secretary,” the OMB letter stated.
Quelle: SN
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Update: 12.01.2021
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NASA's Europa Clipper has been liberated from the Space Launch System
Almost unnoticed, tucked into the 2021 fiscal NASA funding section of the recently passed omnibus spending bill, is a provision that would seem to liberate the upcoming Europa Clipper mission from the Space Launch System (SLS).
According to Space News, the mandate that the Europa Clipper mission be launched on an SLS remains in place only if the behind-schedule and overpriced heavy lift rocket is available and if concerns about hardware compatibility between the probe and the launcher are resolved. Otherwise, NASA is free to search for commercial alternatives to get the Europa Clipper to Jupiter’s ice-shrouded moon.
Europa Clipper is slated to go into orbit around Jupiter and make multiple flyby maneuvers near Europa, an icy world that many scientists believe has a warm ocean under the ice layer. Life may exist in that ocean, the confirmation of which would be one of the greatest scientific discoveries of this or any other century.
The Europa Clipper being mandated to fly on an SLS to begin with was the result of an unseemly side of congressional budget politics. The space probe was championed by former Rep. John Culberson (R-Texas), who at the time was the chair of the House appropriations subcommittee that funds NASA. In order to get support for the Europa Clipper, Culberson added the SLS mandate, which garnered support from Sen. Richard Shelby ( R-Ala.), chair of the Senate Appropriations Committee. Shelby’s state contains a number of aerospace contractors involved in developing the SLS.
Ironically, Culberson lost his seat in 2018, in part, because his opponent, Rep. Lizzie Fletcher (D-Texas), accused him of being more concerned with space missions than local issues, such as flooding brought on by Hurricane Harvey. Nevertheless, the Europa Clipper continued without its key champion in Congress.
As Ars Technica points out, launching the Europa Clipper on a SpaceX Falcon Heavy saves the mission $1.5 billion. An advantage of using the SLS has been that it allows for a direct path to Jupiter without the time-consuming planetary flyby maneuvers that previous missions to the outer planets have required. The Falcon Heavy alone would not be able to get the Europa Clipper to Jupiter space directly, though it might be able to if equipped with a powerful Centaur kick stage.
Both the economics and physics of getting to Europa change if SpaceX’s Starship, currently under development in Boca Chica, Texas, becomes available to launch the Europa Clipper in the mid-2020s. The Starship is meant to fulfill SpaceX’s CEO Elon Musk’s dreams of settling Mars. But the massive reusable rocket would be available for other things, presumably including sending probes to the outer planets.
The massive cost savings by using a commercial launcher for the Europa Clipper creates other possibilities. The Europa Lander could be placed back on. A mission to Saturn’s frozen world Enceladus may also be greenlit.
The SLS is the result of a Faustian bargain struck between NASA and Congress in 2010. Congress was enraged by then-President Obama’s cancellation of the Bush-era Constellation deep space exploration program. According to then-NASA Deputy Administrator Lori Garver,NASA agreed to the SLS in return for Congress supporting the Commercial Crew program that recently came to fruition with the launch of astronauts to the International Space Station (ISS) on a SpaceX Crew Dragon.
The SLS has since been a lead weight on America’s space ambitions. The SLS slated to launch the Artemis 1 uncrewed mission around the moon is currently stuck in a ground-based “green run” series of tests. The SLS is currently using up a great deal of the money allocated to NASA’s Artemis program. The first flight is scheduled for November 2021 at the earliest.
In the meantime, SpaceX has been flying prototypes of the Starship, albeit only in the atmosphere and with occasionally explosive results. NASA is officially disdainful of the idea of replacing the SLS with the Starship. However, a version of the SpaceX massive rocket ship is in the running as a lunar lander for Artemis. It would not be too great a leap to cut out the SLS entirely and go directly with the Starship, if it were not for congressional budget politics.
And that, as Shakespeare would say, is the rub.
Quelle: The Hill
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Update: 12.02.2021
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NASA to use commercial launch vehicle for Europa Clipper
WASHINGTON — NASA is no longer considering launching the Europa Clipper mission on the Space Launch System, deciding instead to launch the spacecraft on a commercial rocket it will procure in the next year.
During a Feb. 10 presentation at a meeting of NASA’s Outer Planets Assessment Group (OPAG), leaders of the Europa Clipper project said the agency recently decided to consider only commercial launch vehicles for the mission, and no longer support a launch of the spacecraft on the SLS.
“We now have clarity on the launch vehicle path and launch date,” Robert Pappalardo, project scientist for Europa Clipper at the Jet Propulsion Laboratory, said. That clarity came in the form of a Jan. 25 memo from NASA’s Planetary Missions Program Office to “immediately cease efforts to maintain SLS compatibility” and move forward with a commercial launch vehicle, or CLV, he said.
Congress had directed NASA for several years to launch Europa Clipper on SLS, including provisions to that effect in annual spending bills. NASA, though, requested the flexibility to procure an alternative launch vehicle, arguing it needed the SLS to support its Artemis human lunar exploration program and claiming that a commercial vehicle could save NASA as much as $1.5 billion.
The project continued to support both launch options, but warned doing so would become increasingly complex and expensive. A complicating factor emerged in August, when NASA disclosed “potential hardware compatibility issues” between the spacecraft and SLS.
NASA got the relief it sought in the fiscal year 2021 appropriations bill enacted in December, which allowed NASA to use an alternative to the SLS if the agency determined the vehicle was not available or if the hardware compatibility issue could not be resolved. In January, NASA issued a “sources sought” solicitation for commercial launch options for the mission “in anticipation of a full and open competition for the acquisition of launch services of the Europa Clipper mission,” but did not state that the agency had decided to move ahead with a commercial launch of the mission.
The planned trajectory is the same as outlined in the solicitation, with a launch during a 21-day window in October 2024, with the spacecraft arriving at Jupiter in April 2030. The Mars Earth Gravity Assist, or MEGA, trajectory includes a flyby of Mars in February 2025 and of Earth in December 2026.
A drawback of using a commercial launch vehicle is that circuitous route, as a launch on SLS would have allowed Europa Clipper to go directly to Jupiter, arriving less than three years after launch. That longer cruise will increase operations costs for the mission, said Jan Chodas, project manager for Europa Clipper at JPL, during the meeting.
The project selected the MEGA trajectory over alternatives that would have included a flyby of Venus. “This provides simplifications for the flight system,” Pappalardo said. There are backup launch opportunities, such as a similar MEGA trajectory in 2026 and one in 2025 that includes an additional Earth flyby.
While NASA set a Feb. 8 deadline for responses to its sources sought solicitation, the agency released a follow-up notice Feb. 2 announcing its intent to issue a formal request for proposals (RFP) for launching the mission. That RFP is scheduled for release around March 1, with proposals due around April 14.
SpaceX’s Falcon Heavy launch vehicle is the leading contender to launch Europa Clipper, and has been used in planning for alternatives to SLS. The fiscal year 2021 appropriations bill, though, requires NASA to consider all potential launch vehicles, including those not currently part of its NASA Launch Services 2 contract, through a “full and open competition.”
The announcement didn’t state when NASA would select a launch vehicle. At the OPAG meeting, Chodas said she expected NASA’s Launch Services Program, which will manage that procurement, to select a vehicle “in about a year or so.”
The NASA decision to pursue a commercial vehicle is a relief to the project team. “The resolution of the launch vehicle path forward certainly helps the team from the standpoint of not having to carry a lot of dual paths” to support both SLS and a commercial vehicle, Chodas said. “There is a cost savings there as well as an efficiency gain because we all know now that we can move forward expecting a CLV.”
Quelle: SN
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Update: 13.02.2021
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NASA decides to launch Europa Clipper on commercial rocket in 2024
NASA has decided to launch the multibillion-dollar Europa Clipper mission on a commercial heavy-lift rocket in October 2024, and not on the government-owned Space Launch System, officials said Wednesday.
The decision ends a prolonged dilemma for NASA, which until last year was legally required to launch the Europa Clipper mission on the more expensive Space Launch System. The language passed in previous NASA appropriations bills directed NASA to launch the probe on the SLS rocket, but Congress relented in the fiscal year 2021 spending bill passed in December.
Lawmakers gave NASA some flexibility on the launch vehicle decision in the fiscal year 2021 budget, directing the agency to launch Europa Clipper on the Space Launch System only if the rocket is available, and if “if torsional loading analysis has confirmed Clipper’s appropriateness for SLS.”
Europa Clipper managers last year raised concerns about the spacecraft’s compatibility with the Space Launch System due to structural loads the probe will encounter during an SLS launch. NASA officials said last year a Space Launch System rocket would not be available for the Europa Clipper launch until 2025 due to commitments to use SLS rockets on the agency’s Artemis moon missions.
If Europa Clipper was forced to launch on an SLS rocket, NASA would likely have to put the spacecraft into storage to wait for the launcher’s availability, NASA officials said. And an SLS launch would cost up to $1.5 billion more than launching Europa Clipper on a commercial rocket, according to the space agency.
The flexibility provided in the 2021 budget language gave NASA the green light to finally move ahead with a commercial rocket procurement for Europa Clipper.
Bob Pappalardo, Europa Clipper’s project scientist at the Jet Propulsion Laboratory, said Wednesday that NASA managers on Jan. 25 directed the Clipper team to work toward launching the spacecraft on a commercial rocket. Engineers were previously designing the spacecraft to be able to launch on either an SLS or a commercial booster, resulting in extra work and additional costs, and delaying Europa Clipper’s critical design review, a milestone in which the spacecraft’s design is frozen.
“We now have clarity on the launch vehicle path and launch date,” Pappalardo said Wednesday in a meeting of NASA’s Outer Planets Assessment Group. “We’ve received direction in late January from the Planetary Missions Program Office to neck down to a singular launch vehicle path. We received a memo that directs the project to ‘immediately cease efforts to maintain SLS compatibility and move forward with a CLV, a commercial launch vehicle.'”
Launching the Europa Clipper mission on the more powerful Space Launch System would give the spacecraft an extra burst of speed as it departs Earth, enabling a direct trip to Jupiter with a transit time of about two-and-a-half to three years.
With a commercial rocket, like SpaceX’s Falcon Heavy, the spacecraft will have to use gravity assist maneuvers, or flybys, with Mars and Earth to gain enough speed to slingshot into the outer solar system. That will increase the travel time to five-and-a-half years from launch until arrival at Jupiter.
The Europa Clipper mission has a planetary launch window in 2024 that opens Oct. 10 and closes Oct. 30, based on a trajectory calculated by NASA that assumes launch on a commercial rocket. The spacecraft would leave Earth on a course to encounter Mars on Feb. 28, 2025, then return to Earth for a second gravity assist flyby Dec. 2, 2026, putting Clipper on a trajectory to enter orbit around Jupiter on April 11, 2030.
There are backup launch windows available for Europa Clipper in 2025 and 2026, with arrival at Jupiter later in the 2030s.
The longer flight time to Jupiter will add to Europa Clipper’s operations budget, but those costs will be more than offset by the savings from launching on a less expensive commercial rocket.
Jan Chodas, Europa Clipper’s project manager at JPL, said the decision to go with a commercial rocket “certainly helps the team from the standpoint of not having to carry a lot of the dual paths with SLS and a CLV, so there are cost savings there.”
She said there is also an “efficiency gain” for the Europa Clipper team because scientists and engineers can move forward without needing to duplicate work for the SLS and commercial launch alternatives. Chodas said the Launch Services Program at NASA’s Kennedy Space Center in Florida will oversee the launcher procurement effort, resulting in a rocket selection “in about a year or so.”
The Launch Services Program will manage a “full and open competition to select the launch vehicle for Clipper,” said Curt Niebur, NASA’s program scientist for missions to the outer planets. “That competition is starting up.”
NASA released a request for information notice Jan. 26 soliciting responses from U.S.-based commercial launch providers on their capabilities to launch Europa Clipper. The mission is in NASA’s flagship class of interplanetary probes, with a cost commitment of $4.25 billion.
Europa Clipper’s multibillion-dollar cost comes with a requirement to launch the spacecraft on a reliable rocket. NASA said in its Jan. 26 request for information that the launch provider selected for Europa Clipper must accomplish at least three successful flights of the same launch vehicle configuration proposed for Clipper before the mission takes off in October 2024, with at least two consecutive successful launches.
The Europa Clipper spacecraft is expected to weigh more than 13,000 pounds, or at least 6,065 kilograms, with fuel loaded for the journey to Jupiter.
The mass of the spacecraft, coupled with the requirement for a high-speed departure from Earth, means SpaceX’s Falcon Heavy rocket is the only launch vehicle expected to be available in 2024, and also currently operational, that could accommodate the Europa Clipper mission. That likely assumes SpaceX expends the Falcon Heavy’s first stage boosters, devoting all of the rocket’s performance to the launch, and leaving no propellant for recovering the stages.
After entering orbit around Jupiter, Europa Clipper will steer onto a course to make about 45 close flybys with Europa, passing as close as 16 miles, or 25 kilometers, from the icy moon. Fitted with large solar arrays to generate electricity, the spacecraft will take a slightly different path by Europa on each pass, eventually surveying nearly the entire moon with observations from its nine scientific instruments.
Europa is covered in a global ice sheet that cocoons an ocean of liquid water, providing an environment that might be habitable for life. Clipper’s instruments will take high-resolution images and map the composition and topography of Europa’s ice shell. The probe will carry a radar to bounce radio waves off Europa’s interior to determine the thickness and deep structure of the ice sheets, and Clipper will search for evidence of eruptions of water coming through fissures in the ice, which might provide a window into the environment of the liquid ocean below.
Pappalardo said the Europa Clipper mission completed its critical design review in December. The review board identified cost concerns with the mission’s development and operations plans, and the launch vehicle decision as key issues facing the Clipper team. But NASA’s decision to go with a commercial rocket finally alleviates that concern, Pappalardo said.
“The entire project continues to make great technical progress despite COVID-19 impacts,” Pappalardo said.
Quelle: SN
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Update: 25.07.2021
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NASA’s Europa Clipper will fly on SpaceX’s Falcon Heavy
The spacecraft will now fly commercial on its mission to Jupiter’s icy moon
NASA’s Europa Clipper will start its journey to Jupiter’s icy moon aboard a Falcon Heavy rocket built by SpaceX. NASA will pay SpaceX $178 million to launch the vehicle in October 2024.
The Europa Clipper got the green light from NASA in 2015. It will fly by the moon 45 times, providing researchers with a tantalizing look at the icy world, believed to have an ocean lurking under its icy crust. The Clipper is equipped with instruments that will help scientists figure out if the moon could support life.
For years, the Clipper was legally obligated to launch on NASA’s long-delayed Space Launch System (SLS). But with the SLS perpetually delayed and over budget, NASA has urged Congress to consider allowing the Europa Clipper to fly commercial. Switching to another vehicle could save up to $1 billion, NASA’s inspector general said in 2019.
NASA got permission to consider commercial alternatives to the SLS in the 2021 budget, and started officially looking for a commercial alternative soon after.
The SLS has powerful allies in Congress, who have kept the costly program alive for years, even as it blew past budgets and deadlines. The first flight of the SLS was originally supposed to happen in 2017. That mission — launching an uncrewed trip around the Moon — has since been pushed to November 2021, and keeping to that new schedule remains “highly unlikely” according to NASA’s Office of Inspector General, a watchdog agency.
SpaceX first launched its Falcon Heavy rocket in 2018, and started flying satellites in 2019. Earlier this year, NASA selected the rocket as the ride to space for two parts of a planned space station orbiting the Moon.
Quelle: The Verge
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Update: 9.08.2021
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A Few Steps Closer to Europa: Spacecraft Hardware Makes Headway
Take a closer look at the complex choreography involved in building NASA’s Europa Clipper as the mission to explore Jupiter’s moon Europa approaches its 2024 launch date.
The hardware that makes up NASA’s Europa Clipper spacecraft is rapidly taking shape, as engineering components and instruments are prepared for delivery to the main clean room at the agency’s Jet Propulsion Laboratory in Southern California. In workshops and labs across the country and in Europe, teams are crafting the complex pieces that make up the whole as mission leaders direct the elaborate choreography of building a flagship mission.
The massive 10-foot-tall (3-meter-tall) propulsion module recently moved from NASA’s Goddard Space Flight Center in Greenbelt, Maryland, to the Johns Hopkins Applied Physics Laboratory (APL) in Laurel, Maryland, where engineers will install electronics, radios, antennas, and cabling. The spacecraft’s thick aluminum vault, which will protect Europa Clipper’s electronics from Jupiter’s intense radiation, is nearing completion at JPL. The building and testing of the science instruments at universities and partner institutions across the country continue as well.
The mission is also gearing up for its System Integration Review in late 2021, when NASA will review plans for assembling and testing Europa Clipper, and its instruments are inspected in detail.
“It’s really exciting to see the progression of flight hardware moving forward this year as the various elements are put together bit by bit and tested,” said Europa Clipper Project Manager Jan Chodas of JPL. “The project team is energized and more focused than ever on delivering a spacecraft with an exquisite instrument suite that promises to revolutionize our knowledge of Europa.”
Jupiter’s icy moon Europa, which harbors an internal ocean with twice the amount of water in Earth’s oceans combined, may currently have conditions suitable for supporting life. Europa Clipper will carry a broad suite of science instruments into orbit around Jupiter and conduct multiple close flybys of Europa to gather data on its atmosphere, surface, and interior.
Hardware in the Works
Delivery of the towering propulsion module from Goddard to APL marked a milestone for that major piece of hardware. APL built the twin cylinders that make up the module and shipped them to JPL, where technicians added thermal tubing that will carry coolant to keep the spacecraft from getting too hot or too cold in deep space. From there, the cylinders went to Goddard, where propellant tanks were installed inside of them and 16 rocket engines were attached to the outside.
Another large piece of hardware nearing completion is the spacecraft’s radiator, which connects to the thermal tubing. The width and length of a twin-size bed, the radiator’s 3-inch-thick (7.5-centimeter-thick) panel has the crucial job of radiating heat out into space to keep the spacecraft within its operating temperature range. It is covered with louvers that open and close automatically as the spacecraft disperses more or less heat to regulate its temperature.
Meanwhile, work at APL begins to integrate the propulsion module and the telecommunications hardware (electronics, radios, antennas, and cabling). And construction of a high-gain antenna – a dish nearly 10 feet (3 meters) wide – is underway at vendor Applied Aerospace Structures Corporation in Stockton, California. It will be delivered to APL this year, where it will be integrated before the entire module comes back to JPL a final time. By the spring of 2022, the huge element will join other Europa Clipper hardware streaming into JPL’s main high bay for assembly, test, and launch operations (ATLO).
One of the first elements in place for ATLO will be the spacecraft’s vault, now entering its final stage of fabrication at JPL. Eventually, the vault will be bolted to the top of the propulsion module and affixed with miles of cabling so that the power box and computer inside can communicate with the other subsystems.
Attached to the vault will be a deck, also completing assembly at JPL, that will support many of the instrument sensors. Called the nadir deck, it stabilizes the spacecraft’s sensors and helps ensure they are oriented correctly.
Science Instruments Nearing Completion
At the same time that the spacecraft body, electronics, and engineering subsystems come together, nine science instruments are being assembled and tested across a network of clean rooms at NASA centers, partner institutions, and private industry vendors. The suite of instruments will investigate everything from the depth of the internal ocean and its salinity to the thickness of the ice crust and potential plumes that may be venting subsurface water into space.
Slated to be delivered to ATLO from late 2021 through mid-2022, the instruments, which include cameras to capture surface geology in detail, are undergoing extensive testing. Engineers want to be sure the instruments can communicate correctly with the flight computer, spacecraft software, and the power subsystem, to be able to respond to commands and transmit data back to Earth.
Mission leaders acknowledge that COVID-19 challenges have stretched the project and instrument teams as they find ways to meet deadlines when parts are delayed or staffing is short. Engineers, technicians, and scientists continue to power through.
“What we’ve seen, even in the midst of the pandemic, is that the engineering and instrument teams are responding very well. The pandemic has affected mission schedule, but the teams are tackling the challenges, communicating openly, and displaying tremendous flexibility to keep the hardware on track for our October 2024 launch,” said Europa Clipper Deputy Project Manager Jordan Evans. “We see it day in and day out, across the team, and it’s fantastic.”
More About the Mission
Missions such as Europa Clipper contribute to the field of astrobiology, the interdisciplinary research on the variables and conditions of distant worlds that could harbor life as we know it. While Europa Clipper is not a life-detection mission, it will conduct detailed reconnaissance of Europa and investigate whether the icy moon, with its subsurface ocean, has the capability to support life. Understanding Europa’s habitability will help scientists better understand how life developed on Earth and the potential for finding life beyond our planet.
Managed by Caltech in Pasadena, California, JPL leads the development of the Europa Clipper mission in partnership with APL for NASA’s Science Mission Directorate in Washington. The Planetary Missions Program Office at NASA’s Marshall Space Flight Center in Huntsville, Alabama, executes program management of the Europa Clipper mission.
Quelle: NASA
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Update: 29.08.2021
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Prepping the Europa Clipper's Propulsion Tanks
Contamination control engineers in a clean room at the Goddard Space Flight Center evaluate a propellant tank before it is installed in our Europa Clipper spacecraft. The tank is one of two that will be used to hold the spacecraft's propellant. It will be inserted into the cylinder seen at left in the background, one of two cylinders that make up the propulsion module.
With an internal global ocean under a thick layer of ice, Jupiter's moon Europa may have the potential to harbor existing life. Europa Clipper will swoop around Jupiter on an elliptical path, dipping close to the moon on each flyby to collect data. Understanding Europa's habitability will help scientists better understand how life developed on Earth and the potential for finding life beyond our planet. Europa Clipper is set to launch in 2024.
Quelle: NASA