NASA Sace Shuttle prospects beyond 2010

Clouds of concern surround space agency program for replacing US national icon.

By A J S Rayl
Contributing Editor, The Planetary Society

Space Shuttle Atlantis takes flight on mission STS27 in Dec 1998 using 375,000 lbs of thrust produced by its 3 main engines. STS27 was the 3rd classified mission dedicated to the US Dept of Defense. After completing its mission Atlantis landed at Edwards AFB in California.

If everything goes as planned, the final flight of the Space Shuttle will deliver a shipment of spare parts to the International Space Station (ISS) on May 31, 2010, then make one final, rocking re-entry and toast the end of an era.

Not long after that, NASA's gleaming new spaceforce-the Orion crew capsules designed to blast off on Ares rockets-will begin ferrying crews to and from the ISS. By 2020, according to the current flight plan, Orion, aboard a larger Ares with an Earth departure stage and lunar lander, will transport crews out of low Earth orbit (LEO) and back onto the Moon-specifically, to the polar regions where the space agency plans to establish an outpost.

There, astronauts will prepare to go "to Mars and beyond in the first half of the 21st century." The words belong to President George W Bush, who unveiled this Vision for Space Exploration in Jan 2004, charging NASA with using the remaining shuttle flights to finish the ISS, and with finding a replacement for Atlantis, Discovery and Endeavour-the remaining $3-billion workhorse orbiters.

The Space Shuttle's final 10 flights are scheduled to fly in the next year and a half, and development of Ares/Orion is now well under way-but things have not been going as planned.

Test pilot's dream

First announced by President Richard Nixon in Jan 1972, the Space Shuttle, officially called the Space Transportation System (STS), finally took off when Columbia launched on Apr 12, 1981-20 years to the day after the Soviet Union's Yuri Gagarin became the first man in space.

Concept image showing the Ares I crew launch vehicle (L) and Ares V cargo launch vehicle. Ares I will carry the Orion crew exploration vehicle to space. Known as "the Stick," Ares I consists of a single solid rocket booster derived from the boosters used in the Space Shuttle system, connected at its upper end by an interstage support assembly to a new liquid-fueled second stage to be powered by an uprated Apollo-era J2X rocket engine.

Its pilot, Robert Crippen, who was a rookie astronaut but highly experienced in putting new naval aircraft through the paces, called it a "test pilot's dream." In the 122 flights since then, the program has made human spaceflight, if only in LEO, part of everyday life.

Shuttle flights have become so routine that news of another mission brings yawns to the vast majority of people nowadays, even as it gives another lucky handful of astronauts the experience of living and working in the microgravity of space.

"As the first-generation reusable spaceship, history will record the Shuttle as a remarkable technological achievement," says John Logsdon, the long-time director of the Space Policy Institute at George Washington University, and now a senior fellow at the National Air & Space Museum in Washington DC.

From the Space Shuttle's altitude, designed to range between 115 miles (185 km) and 596.5 miles (960 km), we have seen the wrath of fires and hurricanes, the destruction of storms, the ravages of deforestation, the path of pollution, and countries without borders. We have seen the nightlights, the pyramids of Giza and the Great Wall of China.

On board, scientists have carried out pioneering biological, genetics and astrophysics research, flown radar that peered beneath the Sahara Desert, experimented with surgery techniques and launched dozens of satellites, including the Hubble Space Telescope, which has taken us, in turn, on a time-traveling journey back in time to the beginning of it all-the Big Bang.

"What NASA has done with the space station is truly extraordinary," says Louis Friedman, executive director of The Planetary Society, the world's largest space-interest group. "To see those international modules up there with Canadian, Russian, European and Japanese parts-it's an engineering accomplishment the likes of which no one else in the world could do."

After what will be a reign of nearly 30 years, the Space Shuttle-despite the losses of Challenger and Columbia and their crews-will glide into the sunset and "a very welcome and respected retirement," says Logsdon-provided, of course, all 3 remaining orbiters return home intact.

Museum curators, already jostling for possession of Atlantis, Discovery and Endeavour, are banking on it.

Constellation of concern

While there is solid support for NASA again taking humans out of LEO and relaunching what astronaut Gene Cernan, the last man to walk on the Moon, calls "the romance of space," deep concern has begun to swirl around the agency's Constellation program, which is developing the country's new spaceforce.

Engineering model of Dragon capsule at SpaceX's El Segundo CA facilities.

Originally presented as a relatively uncomplicated project that would reuse technology and knowledge from the Space Shuttle and Apollo, the Ares rocket/Orion combination now seems to be riddled with complications.

Ares has been completely redesigned during the past couple of years and is now "more Shuttle-flavored than Shuttle-derived," says Apollo XI Pilot and Moon Walker Buzz Aldrin. In the process, he says, "a lot of things have just gone wrong."

Worse than cost overruns that have resulted from design changes and do-overs, engineering studies have found that harmonic vibrations triggered by the extra segment on the rocket may cause "jackhammer" vibrations that could actually shake the crew to death.

From NASA's perspective, it's all about money-rather, a lack of it. Although 2/3 of the agency's $17-billion annual budget is devoted to human spaceflight, it's not enough to get the Constellation job done and continue to fly the Space Shuttle too, according to NASA officials.

Having to adapt the spacecraft to the Columbia Accident Board recommendations, plus the "unknown unknowns" that pop up in any space technology development effort, has forced NASA to push back its earliest human test flights on Ares/Orion to 2014, according to Constellation Program Mgr Jeff Hanley at the Johnson Space Center.

"We are slowing down the work to match and stay under our available funding, and to do that we had to go to a later date," Hanley told reporters in an August teleconference. Despite those budgetary constraints, however, Hanley announced that engineers have drawn up plans for "springlike electromagnetic mass absorbers" to dampen the potentially deadly jackhammer vibrations.

Time will tell if the fix works or if the design is fatally flawed. In the meantime, other problems have ensued in the design of a launch pad for Ares, the astronaut emergency-escape system on Orion, and the capsule's heat-protection system. Nevertheless, Hanley insists the program is moving forward successfully.


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