THE Jules Verne doesn't look like much—a squat, cylindrical ship resembling a bulky communications satellite. At its center is a cargo bin big enough to store more than seven tons of supplies, from oxygen and water to spare batteries and food. Despite its workaday role, the vehicle will be twice as large as anything ever launched on an Ariane rocket. And it will incorporate technology Europe has never had before.
Reacting in part to NASA's reluctance to share any hardware that might have military applications, ESA turned to Russia to purchase the docking mechanism, which allows the vehicle to hook up to the station. The Europeans were also drawn by Russia's work on autonomous docking. ESA engineers improved on the Russian design by adding a guidance system that allows the vehicle to dock without any human intervention at all. One of the biggest problems in docking is knowing the exact orientation of the ship relative to the station; if tab A is going to fit into slot B, the tab and the slot cannot be askew. The old Progress has an onboard radar system that can tell how far the ship is from the station and what its approach angle is, but it provides no information about the station's orientation. The Jules Verne has a more advanced system, built around a camera with image-recognition software that zeros in on the five reflective markers arranged in a pyramid shape on the space station. From the pattern of those reflectors, the Jules Verne's computers can figure out if it is approaching the station from the proper direction or if it needs to maneuver and try again.
Although the Jules Verne is far from being a manned space capsule, or "crew-transfer vehicle" in engineering terms, ESA officials are confident that they can and should transform it into one. "The automated transfer vehicle is for cargo, not astronauts, but it could be adapted," Sacotte says. "To be dependent on one technology—the space shuttle—is not safe." He says a European space capsule would not replace the space shuttle. But it could be useful to ferry crews to low Earth orbit or even to the moon. The ship's cargo hold is large enough to carry three astronauts easily, and it could transport as many as six people over short distances. Even in the current, cargo-only version, the hold is pressurized and insulated.
At a meeting of European ministers this month, Sacotte may propose expanding the automated transfer vehicle to carry crew. It is not clear, however, how the ministers will respond. There are no official estimates of how much the conversion will cost, but it will not be cheap. The potential consequences of safety problems on a manned ship are far greater than on an unmanned cargo
THE TEST CHAMBER
Photo by Ferit Kuyas
The 80,000-cubic-foot Large Space Simulator at the European Space Research and Technology Center is one of the world's most sophisticated spacecraft test chambers. It mimics the effects of vacuum as well as those of sunlight and radiation in space. The resulting data have helped the European Space Agency hone its recent successful robotic missions, including the Huygens lander on Titan and Mars Express.
ship. "We would have to think of any kind of malfunction," says Jean-François Clervoy, a former flight-test engineer and astronaut who works on the transfer-vehicle team, "and then figure that if it had any two at once, we must still be able to save the vehicle." The biggest safety limitation is that the Jules Verne has no reentry capability. It is designed simply to burn up. (A controlled landing seemed beside the point, since the vehicle will be filled to the brim with space-station garbage on the way back.) ESA could add a small reentry capsule onto the vehicle, but it would eat up space and limit the payload to three astronauts.
In their search for funds, ESA officials are talking about shaking loose money earmarked for the space station. They could justify that move because NASA, as part of its original obligation to its space station partners, was supposed to build an emergency escape vehicle to carry astronauts back to Earth. NASA came up with a concept called the X38—an escape pod with a lifting-body design, shaped like a fat wing, that was supposed to land using a steerable parachute—but it became clear that the design was too expensive. Director Sean O'Keefe killed it when he took the helm at NASA in 2001. ESA officials could propose participating with the Americans in the creation of a new escape vehicle to stand in for the canceled X38. NASA might then use a version of that vehicle to carry astronauts back to the moon.
If that gambit fails, or if ESA simply wants to hedge its bet, Europe might collaborate with Russia on the Clipper, a partially reusable vehicle that looks like a squatter, smaller space shuttle. Like Europe's proposed crew-transfer vehicle, the Clipper would sit atop a rocket (rather than strapped on like the space shuttle) and could carry astronauts to the International Space Station, the moon, and beyond. In principle it would replace both Russia's unmanned Progress capsule and the manned Soyuz—the one that caused André Kuipers such discomfort. At its December meeting, ESA is expected to request $60 million to begin development work on the Clipper. The final project would cost a total of $300 million, a pittance compared with the nearly $5 billion NASA spends annually on its shuttle program. Russian space officials say the Clipper could begin flights by 2011.
GETTING astronauts out of Earth orbit and onto the moon or Mars is only one element of a robust manned space program. For the much longer voyage to Mars, robotic craft are essential, both as scouts to find good landing sites and as cargo ships to ferry supplies and equipment. Europe has taken the lead in developing an innovative, extremely efficient propulsion technique for such unmanned missions.
The technology got a test run last year, when ESA's Smart-1 arrived at the moon and began snapping images of the surface. The launch of the lunar orbiter hardly made news in the United States. The event hardly made news in Europe either, probably because sending a small probe to a destination that the Apollo astronauts visited 35 years ago no longer seems like a big deal. But the significance of Smart-1 is how it got there.
Smart-1 set out conventionally, atop an Ariane 5 rocket launched from French Guiana. Once it reached its transfer orbit, peaking at 22,000 miles above Earth, the craft unfolded a small pair of solar panels, and its engine began producing a dim blue glow, gently lifting Smart-1 into higher and higher orbits around Earth. After 17 months of continuous acceleration, the probe reached an orbit so high that it overcame Earth's gravity and was captured by that of the moon. It then began peering with an infrared camera into lunar craters in search of signs of ice and measuring topography with radar and optical cameras. Meanwhile, the engines kept firing, sending Smart-1 into a set of ever-tighter orbits. One British tabloid's headline aptly declared, "Europe's First Lunar Voyage to Use Star Trek–Style Ion Power."
Much of the credit for Smart-1's success belongs to physicist Jose Antonio Gonzalez del Amo, who has spent the past 16 years developing ion propulsion at the Noordwijk laboratories. Gonzalez, a boyish man with a thick shock of unruly brown hair, picks up a version of the probe's engine to demonstrate the simplicity of the technology. It is nothing more than a flat, cylindrical chamber with a round metal grille on one side. The engine creates thrust by accelerating xenon ions—atoms stripped of one or more electrons, giving them a positive charge—through the negatively charged grid and spewing them out the back of the ship at 4,000 miles per hour.
Ion propulsion is a godsend for Europe's space program: cheap, reliable, and extremely efficient. Ion exhaust is much faster than the exhaust from a chemical rocket, so an ion engine can produce 10 times as much thrust from each pound of fuel. That drastically reduces the amount of propellant the ship needs to carry, the size of its fuel tanks, and its total weight. Smart-1's entire voyage required just 165 pounds of xenon gas and the electricity generated by the craft's 46-foot-wide span of solar panels.
The trade-off for efficiency is poor acceleration. Smart-1's engine generates a mere .07 newton of thrust, about the effort your hand has to exert to overcome the weight of a postcard. That is why Smart-1's voyage to the moon took 17 months. An ion-powered ship would need about five years to make a one-way trip to
Mars, compared with seven months for a ship powered by chemical rockets. The crew might travel to Mars by chemical thrust, and the cargo could be sent ahead of time by ion power. "I did the calculations years ago," Gonzalez says, pulling a notebook from his shelf. "With ion propulsion, you could afford to double the payload on a trip to Mars. Really, Mars is too close—you don't have time to get up enough speed. But ion propulsion would work well for Mercury and for the outer planets." NASA tried an ion engine once, on its experimental Deep Space 1 probe, but never followed up. The Europeans seem more committed to the technology: ESA's upcoming unmanned Mercury craft, BeppiColombo, will use ion engines too.
Gonzalez faces a challenge in upsizing ion propulsion so that it can work to supply human-scale missions to Mars. Getting an 11-ton cargo payload there in five years would require about 150 times as much thrust as sending Smart-1 to the moon. Supplying the necessary electricity would require a huge array of solar cells, roughly 10,000 square feet. A much tidier solution is a nuclear power source, which is far more compact and delivers a steady flow of electricity, regardless of its distance from the sun. At the mention of this possibility, however, Gonzalez's excitement drops, as though he had bitten into something sour. In Europe, the nuclear option is not acceptable. "It would be nice to have a nuclear reactor," says Gonzalez. "But we will have to make do without one."
EUROPE'S Aurora manned space program may have the giddy quality of a dream, but solving its twin challenges—building a vessel to carry a crew into deep space and designing the engines that can reach interesting destinations—pushes it toward mundane pocketbook realities. In its proposal to the ESA board, the Aurora planning commission weakly warned that "cost estimates are at this stage just guesses." The figure will most likely run into the tens of billions of euros, a huge stretch beyond Europe's modest space budget. Still, Aurora got a significant boost in July when Germany, which has the largest economy within the ESA, agreed to participate in the program.
Meanwhile, Europe is actively courting China, which sent its first astronaut, Yang Liwei, into space two years ago on a white-knuckle ride reminiscent of the first Mercury missions. Although China's technology is antiquated, the country is modernizing rapidly and can draw on breakneck economic growth to support plans for lunar colonies. "You'd be shocked to know how much money China is spending on its manned space program," says Manuel Valls Toimil, the head of program integration for ESA's manned missions. He is leading efforts to negotiate a partnership. The agency is also cultivating its ties with Russia and Japan and could act as an intermediary in combining the resources of the two nations—which, for historical reasons, refuse to collaborate directly with each other.
The real money in space travel is still with NASA, and its shuttle is still the only vehicle large enough to carry astronauts like André Kuipers into orbit in comfort. Michael McKay, head of ESA's advanced mission concepts and technologies office, argues that the most plausible way to get humans back to the moon and onto Mars is through international collaboration. But collaboration does not mean that ESA will accept a role as a junior partner. "We are very encouraged by NASA's declarations," McKay says, "but NASA has had difficulties meeting its commitments. This should be a partnership of equals, with respect on both sides." At least until ESA finds the means to travel on its own dime.
EUROPE'S STEPPING STONE TO MARS
The European Space Agency's Aurora program outlines a progression of missions to stretch the agency's capabilities. A preliminary timetable envisions a manned mission to the moon in 2024, an unmanned test spaceship to Mars in 2026, and a cargo ship there in 2030. European astronauts would finally set down on Mars in 2033. The plan assumes no major breakthroughs in materials or propulsion technologies.
>The vehicle that would take Europeans to Mars would be assembled in low Earth orbit over two to six years and would require 29 rocket launches lifting 1,700 tons of material and equipment. The current design concept has three building blocks:
>A propulsion module consisting of four stages, each with four Vulcain 2 rocket engines (now being readied for an upgrade of ESA's Ariane 5 rocket), to propel the spacecraft from low Earth orbit to Mars.
>A cylindrical transfer habitation module, 65 feet long and 20 feet in diameter, to house the crew on its journey to and from Mars. Facilities include crew quarters, exercise and work stations, a kitchen, a social gathering area, and the capsule for the reentry of Earth's atmosphere at the end of the mission. Four solar panels, 17 feet by 50 feet, provide electricity.
>A Mars excursion vehicle, 40 feet long and 20 feet wide, to provide transport to and from the planet. It has three parts. A descent module equipped with an inflatable heat shield, parachutes, and a propulsion system takes the astronauts and their hardware to the surface. A surface habitation module houses them while they are on the ground. A Mars ascent vehicle—a two-stage rocket and crew capsule—returns the astronauts to the transfer habitation module, which then breaks from Mars orbit and heads back to Earth.
>Launch is tentatively set for April 8, 2033, when Earth and Mars are closest together. New launch windows open every 26 months, but any delay means a longer trip to Mars, which increases the amount of fuel needed and exposes the crew to more radiation along the way. The spacecraft would carry six astronauts; three would land on the surface, while three would remain in orbit around Mars.
>The ideal mission timeline runs as follows: 200 days from Earth to Mars, 571 days in Mars orbit and on the surface, and 207 days from Mars back to Earth, for a total duration of just over 2 and a half years.
>Even with 3 and a half inches of shielding on the ship, male astronauts would be exposed to enough radiation to increase their risk of cancer by up to 20 percent; for women, the risk would be even higher. Exercise and therapeutic time in a centrifuge would help avoid the chronic bone loss that occurs in zero g.
>Once the astronauts are on Mars, their journeys outside the landing craft will be limited to six hours. They will always travel in pairs, leaving one person in the landing vehicle. Trips will be limited to about half a mile of walking from the landing vehicle or three miles of driving in a rover.
>ESA has not set a price tag on its Mars mission but recognizes the magnitude of the task. "Europe is determined to get to Mars, but we can't do it by ourselves. We need to go there as part of an international effort," says Piero Messina, head of external and institutional relations for the Aurora program. Interestingly, the final stages of ESA's timetable look very much like the equivalent plan taking shape within NASA. Barring the discovery of an ultra-low-cost energy source, a merger of the two programs will likely be necessary before any human sets foot on another planet. —Zach Zorich
The European Space Agency has posted a set of online resources about its Aurora program. See www.esa.int/SPECIALS/Aurora.
The ESA also offers access to its preliminary plans for a manned Mars mission. Go to ftp://ftp.estec.esa.nl/pub/aurora/Human_Missions_to_Mars.
Imagining Space: Achievements, Predictions, Possibilities, 1950–2050. Roger D. Launius and Howard E. McCurdy. Chronicle Books, 2001.
For current information about SMART-1, visit www.esa.int/SPECIALS/SMART-1.
NASA's next generation of ion propulsion is being developed by the Glenn Research Center: www.grc.nasa.gov/WWW/RT2002/5000/5430patterson.html.
The last 50 years of Russian and U.S. space exploration is examined in Space: A History of Space Exploration in Photographs, text by Andrew Chaikin, Firefly Books Limited, 2004.