ESA weighs plan to scrap 2016 ExoMars entry, descent and landing demo
The European Space Agency (ESA) is considering a plan to scale back or eliminate the entry, descent and landing element of a robotic science mission to Mars in 2016, a cost-saving measure that could bolster a more ambitious joint U.S.-European rover mission to the red planet two years later.
Alvaro Gimenez, ESA's director of science and robotic exploration, says Europe could save about €120 million ($174 million) if the 19-member space agency immediately abandons development of its ExoMars Entry, Descent and Landing Module (EDL), a testbed designed to demonstrate Europe's mastery of lander technology. Slated to launch in 2016, EDL is designed to be carried aboard a telecommunications satellite equipped with a methane-sniffing trace-gas sensor and a data relay capability indispensible to a subsequent ExoMars mission planned for 2018.
Of the €345 million in industrial costs ESA has budgeted for the 2016 ExoMars mission, “about €120 million could be saved” if the agency opts to scrap the 600-kg (1323-lb.) EDL tech demo, Gimenez says, though the decision to do so would need to be reached soon.
“If we wait until next year, the savings would be half,” he says, adding that ESA's ExoMars industry team, lead byof Italy and France are already working on the EDL and Mars Trace Gas Orbiter in preparation for launch in early 2016. Gimenez expects to present a range of options—including the possibility of scrapping the EDL—to ESA's human spaceflight, microgravity and exploration program board in September.
“If they tell me to [scrap] it, I'll do it, but we have to move now,” he says. “If we miss the opportunity of 2016, we have a problem. I cannot keep industry around playing cards and being paid by us.”
The European work is a key step in the emerging joint/ESA Mars Exploration program, which ultimately hopes to return samples of Martian soil and rocks to Earth for detailed analysis. Current plans—which face funding uncertainty on both sides of the Atlantic—call for a joint rover mission in 2018 to collect and cache material for a sample-return lander to be launched later.
's Mars Science Laboratory (MSL), set for launch as early as Nov. 25 (see p. 38), is designed to help scientists home in on the types of rocks they want to study first-hand. While carrying sophisticated instruments for in situ chemical analysis of material it collects robotically, the MSL will not be able to match detailed work done by human scientists.
“There's a big difference between taking a rock and grinding it up and doing a measurement on it, compared to picking a rock apart and taking each of the little mineral grains and analyzing them,” says Michael Meyer, lead scientist in NASA's Mars Exploration program. “It's almost like getting a book and you shuffle the pages and try to figure out what the story is, versus you actually look at them in sequence. There are a lot of things that you can't do unless you handle the sample—thin sections, electron microscopy.”
With a decision on the way forward unlikely before fall, ESA's industrial partners have slowed work on the 2016 EDL and Mars Trace Orbiter to a trickle, though ESA Project Manager Thomas Passvogel says the effort is still funded under an earlier contractual arrangement.
Scaling back or nixing the EDL would require ExoMars program managers to rearrange workshares among industrial partners, including Italy and France, which are leading EDL development.
In June, Yannick d'Escatha, head of the French space agency CNES, said France would prefer to abandon the EDL in favor of fortifying the 2018 mission with additional funds.
“Because the 2018 mission is a priority, it needs to be protected,” d'Escatha said in June. “We need to be absolutely sure that the 2018 mission will exist” with Europe's key scientific priorities for the ExoMars rover intact.
Gimenez says Europe has budgeted €1 billion for ExoMars overall, including €605 million in industrial contracts for both the 2016 and 2018 missions. However, member nations have committed just €850 million to date. The remaining €150 million needed to ensure operations and data analysis following launch is currently in flux.
“The members will only subscribe the €150 million at the ministerial meeting in 2012,” Gimenez says, referring to a late 2012 meeting of ESA ministers that will set the agency's multiyear budget. “We are not going to launch something that we are not going to operate afterward. So that amount is needed. If our member states are not able to put [up] their part of the €150 million, the others will have to react, increase their percentage or we have to descope because of that.”
Of the program's two largest contributors—Italy and the U.K.—only the latter has committed to fund some part of the remaining €150 million. Italy, Gimenez says, is still an unknown.
“If they cannot put in their subscription, then we may have a problem,” he notes.
In addition, Gimenez argues that scrapping EDL would mean forfeiting an opportunity to demonstrate European autonomy in key technologies needed for future visits to Mars.
“It is a technology demonstration that is a complicated one, but Europe wanted to have the capability of landing by ourselves, despite the fact that we are going to land with NASA in 2018. I think it's good not to give up that technology if we are serious about exploration in the future.”
Still, Gimenez says the savings could be applied to the NASA-led ExoMars mission in 2018, which is already undergoing a complete design overhaul in the face of mounting budget pressure in Washington. Designed to send an ESA rover with a drill and a science payload alongside a NASA drone equipped with a soil cacher to the red planet, the mission was scrapped in March when NASA said budget cuts would force the agency to reduce its planned $2.2 billion contribution by about $700 million.
Both sides have since returned to the drawing board and are developing a plan to combine the two rovers into a single, larger vehicle compatible with the so-called “sky crane” landing system NASA developed for its MSL, a car-sized rover slated to launch to the planet in November.
“Given budget constraints facing both agencies, NASA and ESA have been in discussions on revised plans for the implementation of the Mars 2016 and 2018 missions,” NASA spokesman Bob Jacobs says. “We hope that by the September timeframe, we'll be in position to move forward with a plan for the successful implementation of both missions.”
Gimenez says NASA's financial contribution as the lead agency for the 2018 mission is critical to ESA's efforts to continue work on the 2016 mission.
“We cannot go ahead for the 2016 mission if we are not totally sure about 2018. If there is no commitment from NASA then we will not proceed with the industrial development for 2016,” he says.
However, Gimenez says that in addition to cost-savings in Europe, scaling back or scrapping the EDL could reduce NASA's launch costs.
“We could have a lighter one or we could have no lander, and that of course affects very easily the cost of the launcher for NASA,” he says. “Of course it has to be a significant decrease in the weight, but it's clear if we decrease the weight we decrease the cost to them. It's heavy stuff.”
In addition to demonstrating European entry, descent and landing technologies, the EDL is designed to conduct some limited science investigations during its four-day mission on the Martian surface. In June ESA and NASA selected scientific investigations that will probe the atmosphere during the lander's descent stage and return data for the first time analyzing electrical fields on Mars.
During the descent phase, two proposed investigations would use the lander's entry, descent and landing engineering data to reconstruct its trajectory and determine the atmospheric conditions.
The EDL would also be expected to make use of a color camera system that would provide additional scientific data and images of the Martian surface, though a decision on the camera's design is not expected by year-end, ESA says.
The Mars Trace Gas Orbiter, in addition to serving as a data relay capability for the 2018 ExoMars rover, will investigate methane and other atmospheric gases present in small concentrations around Mars, focusing on those that could offer clues as to the existence of life there. The orbiter's scientific instruments, drawn from broad international participation in the effort, will include an infrared radiometer to detect chemicals, dust and any water vapor in the Martian atmosphere, along with spectrometers capable of detecting elements at trace levels, ESA says. Cameras, including stereo and wide-angle, multispectral imagers, will provide pictures of the planet's surface and support other instruments.
As technical experts at NASA and ESA redesign the 2018 ExoMars mission, the two sides expect to present initial designs to the program board in September. Both are expected to settle on a final configuration that meshes NASA's MAX-C Explorer/Cacher drone and ESA's drill-equipped rover, following completion of a number of intensive technical studies later this year.
The agencies will then divvy up workshare for the mission. NASA is expected to contribute the launch vehicle, cruise stage, sky-crane landing system and caching payload. ESA, which is expected to lead development of the rover, would modify current designs to incorporate NASA's soil-caching capability, making it compatible with the MSL landing system, which requires that the rover land on its wheels rather than on a platform, as envisioned under the original dual-rover plan.