ALU

Europa

Europa or Enceladus? If NASA switches from SLS to Falcon Heavy, it won’t have to choose

Jupiter’s icy moon Europa (above left in a reprocessed color view made by images taken by NASA’s Galileo
spacecraft in the late 1990) is thought to have a warm ocean shrouded beneath a layer of ice. Saturn’s icy moon Enceladus (shown in cross section above right)
is also believed to have a liquid ocean between its rocky core and icy crust. Credit: NASA

A version of this opinion piece originally appeared in the Oct. 8 issue of SpaceNews as “Europa or Enceladus? Why Choose?”

Europa, a moon of Jupiter, and Enceladus, a moon of Saturn, are very similar worlds. Both distant moons are thought to have warm water oceans shrouded with a layer of ice.

The oceans of Europa and Enceladus are warmed by the tidal forces of their respective planets and may contain lifeforms that have never seen the sky. Therefore, both moons are prime targets for further exploration. Which one we should explore first?

Three main differences exist between Europa and Enceladus. The Cassini space probe, which orbited Enceladus for 13 years, flew through the geysers of water that erupt from underneath the ice layer through fissures. Cassini found evidence of complex organic molecules that could indicate life beneath the surface of Enceladus. Europa has similar geysers, but the evidence of organic molecules is far less certain. Europa is orbiting in the middle of a zone of intense radiation emanating from Jupiter.

Any space probe that spends too much time in that region would quickly find its electronics fried unless it were heavily shielded. Enceladus’ environment is relatively clear of hard radiation. Nevertheless, Europa is the current first target for NASA, with the Europa Clipper due to launch in the early 2020s and a Europa lander to follow a few years later.

Rep. John Culberson (R-Texas), the chair of the House subcommittee that funds NASA, is a moving force for exploring Europa. Europa Clipper will orbit Jupiter, flying by Europa frequently, before moving out of the radiation zone. Europa Lander will follow once its predecessor maps the Jovian moon and locates some landing sites.

With the planning for the Europa Clipper and the Europa Lander in advanced stages and a powerful member of Congress supporting the twin missions, re-tasking the probes to Enceladus is likely not in the cards.

However, a way may be found to do both. The Europa Clipper and Europa Lander are envisioned to be launched to Jupiter space by NASA’s planned heavy-lift Space Launch System. The SLS will be able to lob huge payloads toward Jupiter on a direct flight path, avoiding the time-consuming gravity assist maneuvers that previous probes to the outer planets have had to use.

The problem with the Space Launch System is that it is a fully expendable rocket that could cost between $1.5 billion to $2.5 billion to launch. NASA is struggling to make the SLS more affordable to operate, but the sad fact is that using the heavy-lift rocket is a great expense for the missions to Europa. NASA does have the option of using a commercial rocket, say the SpaceX Falcon Heavy, to launch the twin missions to Europa.

The Falcon Heavy has a slightly lower lift capacity than the Space Launch System, 64 metric tons to low Earth orbit as opposed to 70 metric tons. And the SLS has a larger fairing that can accommodate a wider payload. Enhancements down the line will increase the Space Launch System’s capabilities even more.

However, the Falcon Heavy has two distinct advantages over the Space Launch System. Even in the totally expendable mode the SpaceX rocket costs just $150 million to launch. Just as important, Falcon Heavy has already flown.

Switching to the Falcon Heavy may cause some trade-offs in designing both the Europa Clipper and the Europa Lander to fit the smaller rocket. However, the cost savings could be plowed into an Enceladus orbiter. A probe could be sent to the icy moon of Saturn and orbit it for as long as necessary to ferret out its secrets.

Indeed, enough money might be left over to land on Enceladus, near one of the fissures, to attempt to ascertain what resides beneath its icy surface. Two icy moons for the price of one sounds like a pretty good deal for NASA and the planetary science community.

A recent NASA Inspector General Report that detailed the continuing cost overruns and schedule slippages experienced by the Space Launch System further makes the case for using commercial rockets to end proves to Europa and Enceladus.


Mark Whittington, who writes frequently about space and politics, has published a political study of space exploration entitled “Why Is It So Hard to Go Back To The Moon?” He blogs at Curmudgeons Corner.

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Committee praises NASA’s planetary science program but raises some concerns

Europa lander

WASHINGTON — NASA has done a good job implementing the recommendations of its latest planetary science decadal survey despite past budget problems, but needs to improve some programs, a recent report concluded.

The midterm assessment of the 2011 planetary science decadal survey, prepared by a National Academies committee and published Aug. 7, found that NASA was able to make progress on both flagship and smaller missions recommended by the survey even with funding cuts in the early years of the decade.

“The committee concluded that despite significant cuts to the Planetary Science Division’s budget early in this decade, NASA has made impressive progress at meeting the decadal survey’s goals,” the committee noted in its final report, a reference to a nearly 20 percent cut in planetary science funding in 2013 to less than $1.3 billion. Its budget has subsequently risen significantly, to $2.2 billion in 2018.

The progress includes work on two flagship-class missions prioritized in the report, a Mars rover mission to cache samples for later return to Earth and a spacecraft to orbit Jupiter’s icy moon Europa. Those concepts have become the Mars 2020 and Europa Clipper missions, respectively, after undergoing redesigns to reduce their projected budgets from the decadal report.

The committee, though, did note concerns about the potential cost of Europa Clipper, a multi-billion-dollar mission. “NASA should continue to closely monitor the cost and schedule associated with the Europa Clipper to ensure that it remains executable” without affecting other missions, the committee recommended. “If the [lifecycle cost] exceeds this range, NASA should de-scope the mission.”

The committee was more skeptical about a third flagship-class mission in the early stages of development, a Europa lander mission. The mission has enjoyed funding well above any administration requests largely due to the advocacy of Rep. John Culberson (R-Texas), who chairs the House appropriations subcommittee that funds NASA and is the most prominent congressional supporter of the mission.

A Europa lander, the committee noted, was not prioritized in the latest decadal survey, which called it a “far term” mission that did not receive a detailed cost and technical assessment at the time. “The midterm committee, although it lacks an official cost estimate, believes the mission cost to be in the multiple billions of dollars range,” it concluded.

“Given its cost and its potential impact on the rest of the planetary science program, the committee concluded that the mission should be vetted within the decadal survey process,” the report stated.

The committee also raised concerns about the future of Mars exploration. NASA’s only Mars exploration under development is Mars 2020, although the agency has started studies of a so-called “lean” sample return architecture announced last August. That would require two more missions, one to collect the cached samples and launch them into Mars orbit, and another to collect the sample canister in Mars orbit and return it to Earth.

The committee concluded NASA should continue to study that Mars sample return architecture, but argued that with no other missions on the books, the sample return missions could be vulnerable to failures of existing Mars orbits that serve as communications relays. No other Mars science missions are under development as well.

“There is a risk that ongoing and soon-to-be landed assets on Mars will be left without telecommunications support because of the aging orbiters. The system is fragile and aging,” the committee stated. “There is currently no vision for a program beyond sample return, either for scientific investigation or to prepare for future human exploration.”

The committee recommended that NASA create a Mars Exploration Program (MEP) “architecture, strategic plan, management structure, partnerships (including commercial partnerships), and budget that address the science goals for Mars exploration” outlined in the decadal survey. “This approach of managing the MEP as a program, rather than just as a series of missions, enables science optimization at the architectural level.”

Another recommendation of the committee was to increase the cadence of the Discovery and New Frontiers programs of low- and medium-cost competitively selected planetary science missions. Budget cuts earlier in the decade affected the pace of competitions in both programs, and NASA has struggled to catch up even with increased funding in recent years.

The committee concluded that, to meet the mission cadence recommended in the decadal survey, NASA select three missions in upcoming competitions expected to take place in 2019 and 2021. NASA selected two missions, Lucy and Psyche, in its previous Discovery competition that concluded in January 2017.

The report also offered advice for the next decadal survey in the planetary sciences, which will likely begin by mid-2020 for publication in the spring of 2022. That survey will need to take into account both new science objectives, particularly in astrobiology, as well as new technologies and capabilities, such as smallsats.

The committee in particular recommended that NASA sponsor 8 to 10 concept studies of missions for potential consideration in the next decadal survey. That includes revisiting a previous study of an “ice giants” mission to Uranus and/or Neptune, citing different scientific objectives in a 2017 study versus those outlined in the decadal survey as well as concerns that “the scientific payload proposed in the study carries significant risk of failing to make the measurements” outlined in the decadal.

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House bill keeps Europa Clipper on track despite launch vehicle uncertainties

NASA’s Europa Clipper remains on track to launch as soon as 2022, thanks to funding from Congress well above the agency’s request. Credit: NASA

WASHINGTON — A House funding bill approved by an appropriations subcommittee May 9 will help keep a mission to Jupiter’s moon Europa on track for a launch in 2022.

The commerce, justice and science (CJS) subcommittee of the House Appropriations Committee approved a spending bill on a voice vote after a brief markup session that made no changes to the legislation, introduced a day earlier. The bill now goes to the full appropriations committee for consideration as soon as next week.

The bill provides more than $21.5 billion for NASA in fiscal year 2019. It specifically includes $545 million for Europa Clipper, a mission to orbit Jupiter and perform multiple flybys of the icy moon Europa, which scientists believe is potentially habitable. The bill also includes $195 million for a follow-on lander mission.

The bill specifies that both Europa Clipper and the lander spacecraft launch using the Space Launch System rocket, in 2022 and 2024, respectively, language included in previous years’ appropriations bills. NASA’s budget proposal offered only $264.7 million for Europa Clipper and nothing for the lander, and projected a 2025 launch for Europa Clipper using a commercially procured launch vehicle.

Rep. John Culberson (R-Texas), chairman of the subcommittee and a vocal advocate of Europa exploration, highlighted the funding for the mission in his statement at the markup. “We’ve also increased funding to the planetary programs, including the vitally important Europa mission,” he said.

The funding that Europa Clipper has received in recent years, well above NASA requests, has allowed it to stay on track for the 2022 launch desired by Congress. “Since the start of this project we have been working towards the earliest possible launch opportunity,” said Barry Goldstein, Europa Clipper project manager, at a May 3 meeting of the National Academies’ Space Studies Board. “We’ve been the fortunate recipient of significant funding.”

That funding, he said, is keeping the project on schedule for a June 2022 launch. The project is currently on a “glide path” towards a preliminary design review in August, with reviews of various instruments and other subsystems ongoing. That would allow the mission to enter Phase C of its development in November.

While work on the spacecraft and its instrument complement is going well, one outstanding issue remains the choice of launch vehicle, he said. Launching on the SLS allows the spacecraft to go directly to Jupiter, while other vehicles would require the use of gravity assists at Earth and Venus to get the spacecraft there, about five years later than on a direct trajectory.

For now, Goldstein said the project was designing the spacecraft to be able to use either approach. “We’ve been making sure that the spacecraft and the instruments were both compatible” with the direct trajectory and gravity-assist alternative, he said.

The introduction of SpaceX’s Falcon Heavy, which performed its first launch in February, does not significantly change the debate. At the meeting, Goldstein showed performance capabilities, expressed in a metric known as characteristic energy, or C3, of several different launch vehicles, including both the Falcon Heavy and one with an additional kick stage. “Both of those are well below the C3 we need to get a direct trajectory to Jupiter with a vehicle of our mass,” he said.

He added that both the original Block 1 version of SLS, as well as the Block 1B with the more powerful Exploration Upper Stage, are the only vehicles with C3 values high enough to allow for a direct trajectory for the six-ton Europa Clipper spacecraft. The less-powerful Block 1 is still sufficient, he said, mitigating concerns about any delays in the development of the Block 1B. “We feel comfortable that both SLS variants would be able to take us on a direct trajectory,” he said.

Goldstein said later in the meeting that the spacecraft is being designed for the “more stressing” case of the gravity-assist trajectory, which will expose the spacecraft to more intense thermal conditions because of the required Venus flyby. A final decision on the launch vehicle won’t come until the project’s critical design review, scheduled for November 2019.

He cautioned that the continued progress on Europa Clipper is dependent on receiving sufficient funding at levels well above what the administration has proposed. That has not been a problem so far, though, thanks to support the mission has in Congress from Culberson.

At the May 9 markup, Culberson passed around a scientific paper with involving a new discovery about Europa and the existence of plumes that offer additional proof that the icy moon has a subsurface ocean of liquid water.

“It’s worth noting that the scientific journal Nature Astronomy just reported that the Galileo mission, back in 1997, flew through a water plume on Europa a thousand kilometers thick. So, the ocean of Europa is venting into outer space,” he said. “The science community has wanted to go there for years, Mr. Chairman, and this bill makes that happen.”

“Just in case I hadn’t seen it?” the full committee’s chairman, Rep. Rodney Frelinghuysen (R-N.J.) asked, looking at the paper. “There it is,” Culberson responded.

As it turns out, the paper in question had not been published yet, and the journal had embargoed its release until May 14.

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NASA may extend space station missions to address potential commercial crew delays

ISS

WASHINGTON — NASA is in discussions with its Russian counterparts about extending some upcoming space station missions as a way to buy more time for development of commercial crew vehicles.

During an April 12 hearing by the commerce, justice and science subcommittee of the House Appropriations Committee on the agency’s fiscal year 2019 budget proposal, NASA Acting Administrator Robert Lightfoot said longer “increments” of crews on the ISS could be one way to provide more schedule margin in the event of additional delays by Boeing and SpaceX in the development of their crewed spacecraft.

“Right now we don’t show a gap” in U.S. access to the International Space Station, Lightfoot said in response to a question posed by subcommittee chairman Rep. John Culberson (R-Texas). “But we’re looking at options at what can we do to not have a gap.”

“We’re working with our partners, our Russian partners, on if we can have longer increments for crew members that go up,” he said.

He revisited that later in the hearing. “One thing we have is a great relationship with our Russians partners, and we’re looking at other alternatives about potentially extending mission duration for the current missions that are there so that we don’t gap the ability to get there,” he said.

NASA’s current agreement with flying astronauts on Soyuz vehicles expires next year, after the agency purchased three seats on Soyuz flights launching in the spring of 2019 and returning in the fall. It’s not clear what would be involved in extending ISS mission durations, such as any technical issues regarding how long a Soyuz spacecraft can remain docked to the ISS.

NASA announced April 5 it had updated its existing commercial crew contract with Boeing to study modifications to the crewed test flight for the company’s CST-100 Starliner. Those modifications would include adding a third astronaut and extending the spacecraft’s stay at the ISS from two weeks to as long as six months. Those changes, Lightfoot noted at the hearing, were another way to mitigate the effects of additional development delays.

At the hearing, Lightfoot said there was still schedule margin for the development of Starliner and SpaceX’s Crew Dragon to be ready by the fall of 2019. Schedules last updated in January call for both companies to make uncrewed test flights of their vehicles in August. Boeing would then make a crewed test flight in November, followed by SpaceX in December.

Lightfoot, though, hinted that those schedules would be delayed again. “We still expect to see the first test flights at the end of this year,” he said, later elaborating that these were the uncrewed test flights for both companies.

Culberson asked when the crewed test flights would take place, and Lightfoot said he would take that for the record. “I’m focused on the uncrewed one right now,” he said.

Juggling the SLS launch schedule

Lightfoot also said at the hearing that NASA was revisiting the schedule for Space Launch System missions based on the unexpected windfall it received in the final 2018 omnibus appropriations bill.

That bill, signed into law March 23, provided $350 million for NASA to build a second mobile launch platform for the SLS. NASA officials said last year a second platform could help shorten the gap between the first and second SLS launches, but did not include funding for it in its 2019 budget proposal, citing competing priorities.

That second launch platform, which would be designed for the Block 1B version of the SLS with the larger Exploration Upper Stage, would reduce the 33-month “iron bar” in the schedule between the first two SLS missions created by the time needed to modify the current platform. That platform has been built to support the Block 1 version of SLS, which uses the Interim Cryogenic Propulsion Stage (ICPS).

Lightfoot said that having a second launch platform opens the door to launching a second SLS mission with the ICPS. That could be used, he said, to launch the Europa Clipper mission, which could be ready for launch as soon as 2022. NASA’s 2019 budget proposal, though, plans a 2025 launch of Europa Clipper using a commercially-procured launch vehicle rather than SLS.

Another option would be to fly the first crewed Orion mission, known as Exploration Mission (EM) 2, on that second SLS Block 1. “If EM-2 flies that way, we would have to change the mission profile because we can’t do what we would do if we had the Exploration Upper Stage,” he said. “But that still gets humans in orbit and still allows us to check out all the systems that we wouldn’t check out on EM-1.”

He indicated that the funding for the second mobile launch platform took the agency by surprise. “You’re going to have to give us a little time, because that was just a couple weeks ago that we found out that we were getting that,” he said.

Defending budget cuts

The two-hour hearing by the subcommittee was largely cordial, with members thanking Lightfoot for his record-setting service as acting administrator. Lightfoot announced last month he will retire from the agency at the end of April.

He was called on by some members, though, to defend cuts in the 2019 proposal. That included NASA’s education office as well as four Earth science missions, all of which the administration sought to cut in 2018 but which Congress ultimately funded.

Lightfoot said it was continuing to work on those programs funded in 2018 despite the administration’s new effort to cancel them. “We are ready to execute as we were asked to do in 2018,” he said.

He added that NASA has looked at ways to make its education office more effective. That office, he said, will soon be renamed the “Next-Gen STEM Office” to focus on science, technology, engineering and mathematics education activities for the next generation. But, should the administration’s proposal to defund the office be approved, he said the agency would focus its education activities through its missions. “That’s going to be how were going to try to inspire the next generation as we go forward,” he said.

“Admittedly, that’s going to be a concern whether that can actually fill the void or not,” he said later in the hearing. “As long as we’re getting appropriated the money, we will have an education office that executes what you guys have asked us to do.”

Committee members also questioned plans to cancel the Wide-Field Infrared Survey Telescope (WFIRST) in the 2019 budget proposal, citing its inclusion as the top-priority large mission in the 2010 astrophysics decadal. Lightfoot said that, should WFIRST be cancelled, NASA would look at ways instrument technology developed for it could be applied to future missions.

Culberson said his subcommittee planned to hold a hearing on issues with both WFIRST and the James Webb Space Telescope, whose launch NASA said last month would be delayed by about a year to May 2020. That hearing is tentatively scheduled for May 9, although Lightfoot said that ongoing reviews of JWST, including one by an independent review board established by NASA after the latest delay, will not be ready in time to support that hearing.

Culberson also offered advice to members concerned about cuts to education or science programs in the administration’s proposal. “The budget, again, is just a recommendation,” he said. “We don’t get too worked up over the budget.”

SpaceNews.com

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NASA may extend space station missions to address potential commercial crew delays

ISS

WASHINGTON — NASA is in discussions with its Russian counterparts about extending some upcoming space station missions as a way to buy more time for development of commercial crew vehicles.

During an April 12 hearing by the commerce, justice and science subcommittee of the House Appropriations Committee on the agency’s fiscal year 2019 budget proposal, NASA Acting Administrator Robert Lightfoot said longer “increments” of crews on the ISS could be one way to provide more schedule margin in the event of additional delays by Boeing and SpaceX in the development of their crewed spacecraft.

“Right now we don’t show a gap” in U.S. access to the International Space Station, Lightfoot said in response to a question posed by subcommittee chairman Rep. John Culberson (R-Texas). “But we’re looking at options at what can we do to not have a gap.”

“We’re working with our partners, our Russian partners, on if we can have longer increments for crew members that go up,” he said.

He revisited that later in the hearing. “One thing we have is a great relationship with our Russians partners, and we’re looking at other alternatives about potentially extending mission duration for the current missions that are there so that we don’t gap the ability to get there,” he said.

NASA’s current agreement with flying astronauts on Soyuz vehicles expires next year, after the agency purchased three seats on Soyuz flights launching in the spring of 2019 and returning in the fall. It’s not clear what would be involved in extending ISS mission durations, such as any technical issues regarding how long a Soyuz spacecraft can remain docked to the ISS.

NASA announced April 5 it had updated its existing commercial crew contract with Boeing to study modifications to the crewed test flight for the company’s CST-100 Starliner. Those modifications would include adding a third astronaut and extending the spacecraft’s stay at the ISS from two weeks to as long as six months. Those changes, Lightfoot noted at the hearing, were another way to mitigate the effects of additional development delays.

At the hearing, Lightfoot said there was still schedule margin for the development of Starliner and SpaceX’s Crew Dragon to be ready by the fall of 2019. Schedules last updated in January call for both companies to make uncrewed test flights of their vehicles in August. Boeing would then make a crewed test flight in November, followed by SpaceX in December.

Lightfoot, though, hinted that those schedules would be delayed again. “We still expect to see the first test flights at the end of this year,” he said, later elaborating that these were the uncrewed test flights for both companies.

Culberson asked when the crewed test flights would take place, and Lightfoot said he would take that for the record. “I’m focused on the uncrewed one right now,” he said.

Juggling the SLS launch schedule

Lightfoot also said at the hearing that NASA was revisiting the schedule for Space Launch System missions based on the unexpected windfall it received in the final 2018 omnibus appropriations bill.

That bill, signed into law March 23, provided $350 million for NASA to build a second mobile launch platform for the SLS. NASA officials said last year a second platform could help shorten the gap between the first and second SLS launches, but did not include funding for it in its 2019 budget proposal, citing competing priorities.

That second launch platform, which would be designed for the Block 1B version of the SLS with the larger Exploration Upper Stage, would reduce the 33-month “iron bar” in the schedule between the first two SLS missions created by the time needed to modify the current platform. That platform has been built to support the Block 1 version of SLS, which uses the Interim Cryogenic Propulsion Stage (ICPS).

Lightfoot said that having a second launch platform opens the door to launching a second SLS mission with the ICPS. That could be used, he said, to launch the Europa Clipper mission, which could be ready for launch as soon as 2022. NASA’s 2019 budget proposal, though, plans a 2025 launch of Europa Clipper using a commercially-procured launch vehicle rather than SLS.

Another option would be to fly the first crewed Orion mission, known as Exploration Mission (EM) 2, on that second SLS Block 1. “If EM-2 flies that way, we would have to change the mission profile because we can’t do what we would do if we had the Exploration Upper Stage,” he said. “But that still gets humans in orbit and still allows us to check out all the systems that we wouldn’t check out on EM-1.”

He indicated that the funding for the second mobile launch platform took the agency by surprise. “You’re going to have to give us a little time, because that was just a couple weeks ago that we found out that we were getting that,” he said.

Defending budget cuts

The two-hour hearing by the subcommittee was largely cordial, with members thanking Lightfoot for his record-setting service as acting administrator. Lightfoot announced last month he will retire from the agency at the end of April.

He was called on by some members, though, to defend cuts in the 2019 proposal. That included NASA’s education office as well as four Earth science missions, all of which the administration sought to cut in 2018 but which Congress ultimately funded.

Lightfoot said it was continuing to work on those programs funded in 2018 despite the administration’s new effort to cancel them. “We are ready to execute as we were asked to do in 2018,” he said.

He added that NASA has looked at ways to make its education office more effective. That office, he said, will soon be renamed the “Next-Gen STEM Office” to focus on science, technology, engineering and mathematics education activities for the next generation. But, should the administration’s proposal to defund the office be approved, he said the agency would focus its education activities through its missions. “That’s going to be how were going to try to inspire the next generation as we go forward,” he said.

“Admittedly, that’s going to be a concern whether that can actually fill the void or not,” he said later in the hearing. “As long as we’re getting appropriated the money, we will have an education office that executes what you guys have asked us to do.”

Committee members also questioned plans to cancel the Wide-Field Infrared Survey Telescope (WFIRST) in the 2019 budget proposal, citing its inclusion as the top-priority large mission in the 2010 astrophysics decadal. Lightfoot said that, should WFIRST be cancelled, NASA would look at ways instrument technology developed for it could be applied to future missions.

Culberson said his subcommittee planned to hold a hearing on issues with both WFIRST and the James Webb Space Telescope, whose launch NASA said last month would be delayed by about a year to May 2020. That hearing is tentatively scheduled for May 9, although Lightfoot said that ongoing reviews of JWST, including one by an independent review board established by NASA after the latest delay, will not be ready in time to support that hearing.

Culberson also offered advice to members concerned about cuts to education or science programs in the administration’s proposal. “The budget, again, is just a recommendation,” he said. “We don’t get too worked up over the budget.”

SpaceNews.com

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Europa lander concept redesigned to lower cost and complexity

A revised concept for the Europa lander mission would reduce its cost by doing away with a dedicated communications relay and simplifying its science requirements. Credit: NASA/JPL

WASHINGTON — Revised concepts for a proposed Europa lander mission could reduce its mass and cost by simplifying its science requirements and doing away with a dedicated communications relay.

In a presentation at a meeting of the Committee on Astrobiology and Planetary Science of the National Academies March 28, Kevin Hand of the Jet Propulsion Laboratory said that feedback from a mission concept review for the proposed lander last June led to changes in the design to reduce its cost.

“The technology and science were well received. The marching orders that we got out of that review were to see if we could simplify the architecture to reduce complexity and cost,” he said. While there’s been little discussion of the lander’s cost, Hand said there was a “desire” to reduce its cost to below $3 billion.

The concept for the mission presented at that review involved the launch of the lander on a Space Launch System rocket no earlier than late 2025. The spacecraft would enter orbit around Jupiter in 2030 with a landing on Europa to follow no earlier than December 2031. The battery-powered lander would operate on the surface for at least 20 days, relying on a communications relay spacecraft in orbit to return data to Earth.

Hand said the project team looked at options to do away with the relay spacecraft by giving the lander a larger antenna to enable direct-to-Earth communications. That concept uses a flat-panel antenna 80 centimeters across, versus antenna smaller antennas 30 to 40 centimeters across intended for communications with the relay. One quadrant of that larger antenna has been built and tested at JPL, he said, with “encouraging” results.

Another factor that enables the change in design, he said, is a shift in the science requirements for the lander. A report by a science definition team last year had included, as one of the mission’s priorities, the ability of the lander’s instruments to directly detect any life that might exist in the moon’s icy surface.

“That’s a very high bar,” Hand said. “That bar runs the risk of setting expectations too high, perhaps, and also potentially cannibalizing some of the other science that the community sees as very valuable.”

Instead, the mission team looked at what the “sweet spot” for science from the lander mission might be. Hand said that looking for biosignatures of past or present life would simplify the science requirements for the mission, including reducing the amount of data needed to be transmitted back to Earth.

“By moving to biosignatures, we are able to reduce that need for a dedicated comm relay, which enables a direct-to-Earth architecture, which is less costly and less complex,” he said. That approach also preserves the proposed instrument payload that supports both biosignature and other science. “We worked very hard not to remove any instruments.”

He added that by focusing on biosignatures, the lander does not necessarily lose the ability to directly detect life, only that it no longer drives the design of the mission. “If you choose your instruments and your investigations wisely, you have the capability of doing life detection, but you are unburdened from some of the requirements of life detection.”

Another change in the lander is a shift away from the avionics being developed for the Europa Clipper multiple-flyby mission. That was intended to save money but resulted in driving up the mass of the lander. Hand noted that a one-kilogram increase in the mass of the lander on the surface of Europa translated into a 30-kilogram increase in the mass of the spacecraft on the launch pad, given the mission’s fuel requirements.

While refining the design of the lander and its science requirements, other work is in progress on the mission’s technology. That includes development of a “terrain relative navigation” system for precise landings on the surface and cryogenic sampling technologies to efficiently cut into Europa’s cold, icy surface to collect samples.

These efforts have continued despite the lander being caught in a tug-of-war between NASA and Congress. NASA requested no funding for a lander mission in its 2018 budget proposal, focusing instead on the Europa Clipper mission. However, the 2018 omnibus appropriations bill signed into law March 23 included $595 million intended for both Clipper and the lander mission, although not specifying how that money should be allocated between the two. NASA’s fiscal year 2019 budget proposal again requested no funding for the lander.

Hand said he would like to move ahead with selection of instruments for the lander, allowing engineers to design around actual hardware rather than concepts for instruments included in the science definition team report. “We have developed the systems as much as we can for generic applications,” he said. “To take it to the next level, we will need to work with real instruments. That’s what I would hope to see in the next year.”

Jim Green, director of NASA’s planetary science division, agreed. “We feel that one of our next major hurdles is instrumentation, and figuring out our next steps in terms of investing in those,” he said, with a meeting planned at NASA Headquarters next week to discuss some of those options.

“I think you’ll see now that the budget is passed, with congressional direction, we’ll be smartly out in a couple of these areas,” Green said.

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NASA budget proposal continues debate on when and how to launch Europa Clipper

NASA’s fiscal year 2019 budget proposal seeks to launch Europa Clipper on a commercial vehicle in 2025, while Congress has sought a 2022 launch on SLS. Credit: NASA

WASHINGTON — NASA’s fiscal year 2019 proposal will likely set up another showdown between NASA and Congress regarding the Europa Clipper mission, debating not only when to launch the spacecraft but also how.

The 2019 budget proposal, released Feb. 12, offers $264.7 million for the mission, which would send the spacecraft into orbit around Jupiter and make dozens of flybys of Europa, the potentially habitable icy moon of the giant planet. That’s down from the $425 million the administration requested for the mission in 2018.

Congress has yet to pass a final appropriations bill for fiscal year 2018, more than four and a half months into the current year. The mission received $237.4 million in 2017, and a House version of a 2018 appropriations bill provided $495 million to be shared by Europa Clipper and a follow-on lander that is still in an early phase of studies. That bill came out of the commerce, justice and science appropriations subcommittee, whose chairman, Rep. John Culberson (R-Texas), is a vigorous advocate for missions to Europa.

The projections for future spending for the mission, included in the 2019 budget proposal, do not foresee significant increases. They call for another decrease, to $200 million, in 2020, then rising to about $360 million per year from 2021 through 2023.

Despite that funding profile, the budget proposal moves up the launch of the mission by a year from previous agency plans. “The budget allows us to pull the Europa Clipper in,” said Jim Green, director of NASA’s planetary science division, in a presentation at a meeting of the Planetary Science Advisory Committee here Feb. 21. “Last year’s budget said we would be able to launch it in 2026. Now we have the funding necessary for us to be to launch it in 2025.”

Green didn’t explain how the funding profile accelerates the launch, but a launch in either 2025 or 2026 would conflict with language in previous appropriations bills calling for a launch of the mission by 2022. The House version of the 2018 spending bill retains that 2022 launch requirement.

NASA, in its 2019 budget request, included an alternative spending profile that would support a launch of Europa Clipper in 2022. That calls for significantly higher funding, peaking at $594 million in fiscal year 2020. “NASA does not recommend acceleration of the launch to 2022, given potential impacts to the rest of the Science portfolio,” the budget proposal states. “The Administration supports a balanced science program, as recommended in the Decadal Survey.”

Those appropriations bills have also specified that Europa Clipper launch on the Space Launch System heavy-lift rocket under development. NASA “shall use the Space Launch System as the launch vehicles for the Jupiter Europa mission, plan for an orbiter launch no later than 2022 and a lander launch no later than 2024, and include in the fiscal year 2019 budget the 5-year funding profile necessary to achieve these goals,” the House version of a 2018 House appropriations bill stated.

NASA, though, is seeking to use instead a commercial launch vehicle that the agency believes will be less expensive than SLS. “The administration would also like us to fly Clipper on a commercial launch vehicle, because there is enormous cost savings, in our current analysis, between commercial and the use of an SLS,” Green said.

NASA has studied launching Europa Clipper on both SLS and on the most powerful variant of the United Launch Alliance Atlas 5. SLS offers the ability to fly a fast, direct route to Jupiter, with the spacecraft arriving at the planet less than three years after launch. The Atlas 5 would take more than six years to get Europa Clipper to Jupiter, and require flybys of both Venus and Earth to do so.

NASA’s 2019 budget request notes those advantages for SLS, but concludes, “the additional costs of adding an SLS flight for the Clipper outweigh the benefits.” It also states that SLS “will be focused on supporting the Administration’s new space exploration strategy and prioritizing the return of astronauts to the surface of the Moon.” An SLS launch of Europa Clipper, it notes, could not take place sooner than 2024 “without disrupting current NASA human exploration plans.”

The budget does not specify how much an SLS launch would cost, but the spending profile supporting a 2022 launch includes $432 million for a commercial launch. That amount, the document adds, “may be reduced as commercial offerings and pricing continue to evolve.”

Besides the Atlas 5, SpaceX’s Falcon Heavy could also launch Europa Clipper. However, that vehicle, which performed its inaugural launch Feb. 6, may still be years away from the NASA certification required for launching Europa Clipper.

Curt Niebur, a program scientist in the planetary science division at NASA Headquarters, said at the Feb. 21 meeting of the Outer Planets Assessment Group (OPAG) in Hampton, Virginia, that the agency was not ruling out using SLS or a commercial vehicle for launching Europa Clipper. “We’re maintaining compatibility with a variety of options, but right now SLS is the baseline,” he said.

Niebur said that NASA doesn’t need to make a formal decision on the launch vehicle for the mission until its critical design review. That review is scheduled for late 2019, according to a schedule chart presented at the OPAG meeting.

That schedule also shows a June 2022 launch for the mission. “We continue to work to a launch as early as June of ’22,” said Bob Pappalardo, Europa Clipper project scientist, at the OPAG meeting. “That’s what the project schedule is currently, and what we’ll continue to work towards.”

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