Space: the elusive frontier

On 19th September 2005, NASA Administrator Dr. Michael Griffin announced the details of The United States’ $104 billion plan to send astronauts back to Earth's moon by 2018 and go on to Mars. Critics called the plan “Apollo Redux.” Supporters called it a “go-as-you-can-pay,”
politically-realistic strategy to keep the United States a spacefaring power.

NASA’s new plan represents a painful accommodation with two conflicting political constraints. The United States is unlikely to fully retreat from human spaceflight -- especially with geopolitical adversaries like China entering the fold. Congress will not let NASA move beyond the Space Shuttle and Space Station if it costs much more than the country already spends.

NASA is giving up an almost four decade “push” to lower the price of reaching orbit. The unsustainably fragile Space Shuttle will be retired by 2010 or earlier. New reusable rocket development and other long-term research with no immediate application will be suspended. Instead, NASA is assembling the technology and money it already has into a focused effort to establish additional human outposts in space, beyond the International Space Station. The market to supply those destinations may “pull” private efforts to create innovative launch vehicles and start the earliest beginnings of trade on the new frontier.

Will this reversal of priorities work? Or, is the United States headed down another blind alley on the elusive road to a spacefaring civilization?

THESE ARE YOUR GRANDFATHER’S ROCKETS

As the Space Shuttle program winds down, old bits from the Shuttle, Apollo Saturn rockets, and the Centaur upper stage – and a few carefully chosen new pieces – will be assembled into two launch vehicles.

The Space Shuttle reusable Solid Rocket Booster, using technology dating from the early 1970s, forms the core of NASA’s new “transportation architecture.” In spite of being the direct cause of the Shuttle Challenger’s loss two decades ago – and impossible to shut down once it is ignited – this redesigned and relatively inexpensive rocket is now considered reasonably safe and reliable.

Crews will be launched on a “single stick” four-segment Shuttle booster with a new cryogenic upper stage powered by one Space Shuttle Main Engine. Retired Shuttle engines will be flown one last time on the new vehicles; when those run out, a simplified, non-reusable version will be deployed. NASA has allocated approximately $3.2 billion to develop this “Crew Launch Vehicle.”

The Space Shuttle’s replacement will be the much smaller Crew Exploration Vehicle. This is a modernized, reusable, scaled up Apollo spacecraft: a blunt cone 5.5 meters in diameter with a crew of four to six. An expendable service module containing tankage, thrusters, and a main engine is mounted behind. Development is underway and is expected to cost some $5.5 billion.

After a series of automated test flights, trial missions to the Space Station are planned for 2012. Ultimately, NASA hopes to off-load this task to commercial operators, jump-starting a new industry delivering bulk cargo to orbit. Future Crew Exploration Vehicles will be dedicated to lunar missions.

After the exploration vehicle and its rocket are safely flying, development will begin on a second rocket. Able to life 125 metric tons – more than the old Saturn-V moon rocket – this behemoth also will be built from cast-off parts from the Shuttle. Two five-segment Shuttle solid rocket boosters will be attached to the sides of a lengthened Shuttle External Tank and five Shuttle main engines will be mounted underneath.

SOMETHING NEW

Not everything can be pilfered from NASA’s rubbish heap. A brand new methane-burning engine is under development for use on the Crew Exploration Vehicle’s service module and a newly designed lander. The relatively simple engine will be pressure fed to avoid complex compressors and turbo pumps that could go wrong on long missions to the planets.

Methane is storable during flight and can be derived from Mars’ atmosphere. Oxygen, for the rocket’s oxidizer (and for breathing by astronauts) is believed to be readily available in the lunar regolith, as well as in Martian aquifers. “Living off the land” could dramatically reduce the mass that must be sent from Earth and is a key feature of Dr. Griffin’s plan.

FLY ME TO THE MOON

The first expedition to the moon since Apollo-17 in 1972 is to get underway circa 2018 with the ignition of the heavy lift vehicle first stage’s five engines and twin solid boosters. A newly-developed Lunar Transfer Stage will fire J-2 rockets – derived from the Saturn upper stages – to complete placing the lander into parking orbit, where it will be thoroughly tested. Then, a Crew Exploration Vehicle with four astronauts will be launched to dock with the lander. The transfer stage’s rockets will re-ignite, sending both spacecraft toward the moon.

The combined Crew Exploration Vehicle and lander will decelerate into lunar orbit with the former’s methane engine. After checkout, the entire crew will pile into the lander, leaving the exploration vehicle unattended in lunar orbit.

The lander’s first stage RL-10 rockets, adopted from the venerable Centaur upper stage, will fire to start the descent out of orbit. These powerful engines can be re-started and throttled for a controlled landing anywhere on the lunar surface, not just near the equator as with Apollo.

The first crew will spend one week testing equipment, experimenting with mining oxygen from lunar soil, and doing some initial exploration and science. Later missions will be launched approximately twice a year to keep annual operations costs under $6 billion. They will quickly expand into “Lewis and Clark” class scientific expeditions of up to six months, beginning as early as 2022. Each crew will leave excess hardware in place so subsequent missions can reuse it, gradually accumulating the material to assemble a permanent base, probably at the lunar south pole.

When it is time to leave, the lander's second stage will lift off with its methane engine, and dock with the orbiting exploration vehicle. The lander will be abandoned as the crew fires the service module engine to head back toward Earth. The exploration vehicle will enter Earth’s atmosphere with the same blunt lifting shape used by Apollo, but will use parachutes and small rockets or airbags to settle down onto dry land.

Mars missions will remain undefined until the lunar architecture is in place to avoid having to develop more than two or three new vehicles at a time. However, two of the most critical developments -- the heavy lift launch vehicle and the methane rocket -- should have years of successful flight operations when they are needed for Mars.

SURVIVING POLITICS

No plan that costs much more than NASA spends now can survive through multiple administrations and congresses. Dr. Griffin did not propose the lowest-cost options, or those most useful to the wider space community (see the cutout box, What's Wrong with Air Force Rockets?). The plan appears to exceed NASA’s projected long-term budget by some $18 billion over thirteen years.

The greatest near-term threat remains the ever-escalating cost of keeping the Shuttle alive long enough to launch Europe’s and Japan’s components for the International Space Station. So far, Dr. Griffin plans to delay milestones to keep the Shuttle flying and develop the new hardware – all while staying within the available funding.

In spite of multiple natural disasters and wars, legislative support remains strong. For the second year, NASA’s budget endorses the early stages of the project.

The stormy weather may be helping NASA’s case: the space agency is one of Louisiana’s largest employers. The new upper stage and the body of the heavy lift vehicle derived from the old Shuttle External Tank are likely to be built at Lockheed-Martin’s factory just outside of New Orleans. Dr. Griffin is carefully spreading the work: most of the Shuttle workforce will not be sacked and NASA announced that automated precursor missions to Earth’s moon will be managed from NASA’s Ames Research Center, politically liberal territory outside of San Francisco.

Is it possible that devastating storms are helping to pave humanity’s road to the planets? If so, it would not be the first time weather and politics combined to change history.

CUTOUT BOX: WHAT’S WRONG WITH AIR FORCE ROCKETS?

The United States’ Air Force has already developed two state-of-the-art Evolved Expendable Launch Vehicles capable of launching twenty tons. Every dollar NASA spends developing and maintaining the new Shuttle-derived launchers is a dollar not spent flying to the moon. Moreover, these vehicles were carefully designed to take advantage of economies of scale. Flying them more often benefits everyone, weather satellites and lunar missions alike.

Prior NASA Administrator Sean O’Keefe’s original idea was to develop a smaller exploration vehicle that would seat fewer astronauts but would fit on any medium-class rocket, including Europe’s Ariane. Using smaller launchers means breaking lunar missions into smaller pieces, which complicates logistics and may incur more risk and long-term expense. However, it reduces up-front costs and would allow the first lunar missions to fly sooner. Smaller vehicles force learning to make do with less, which is no bad thing if you plan to explore the Solar System with a highly constrained budget.

Former congressional staffer and spaceflight analyst Tim Kyger suggests an even cheaper plan he calls “Luna again in 2010!” He would attach an upgraded Russian Soyuz – an early version of which was designed for lunar missions -- to upper stages separately launched by the Air Force rockets. A lander would be sent to the moon using the same technique, then dock with the orbiting Soyuz to transfer the crew for landing. If Dr. Griffin’s plan goes seriously over budget, something like Mr. Kyger’s quick-and-dirty solution may yet see the light of day.

CUTOUT BOX: BUT WHY ASTRONAUTS?

Why spend money sending astronauts to Earth’s moon? NASA Administrator Dr. Michael Griffin paraphrases jazz musician Louis Armstrong, “If you have to ask why we should explore space, you’ll never understand the answer.”

There are more practical reasons. Scientists frustrated at the costs of human spaceflight tend to ignore its advantages and the ultimate limits to robotics.

In his seminal history of the Soviet lunar programs, Challenge to Apollo, Asif A. Siddiqi attempts to compare the scientific value of the Luna landers with the Apollo flights of the same era. While a direct comparison is difficult, he argues it is not clear the 105 gram sample of regolith randomly collected by Luna-16 was more scientifically cost effective than the sixty kilograms carefully selected over wide areas by the first two Apollo crews. “Luna-16 was certainly a remarkable technological accomplishment,” wrote Siddiqi, “but it was probably not, as Soviet officials of the day touted, a ‘cheaper and better’ alternative to Apollo.”

Likewise, the Mars Exploration Rovers are among the greatest achievements of our time, but that project has spent well over a billion dollars and more than two years achieving the initial reconnaissance a human geologist could do in a couple of afternoons.

No foreseeable robot will rule out life on Mars, determine the widespread distribution of any microfossils, detail the stratigraphic history of Martian volcanic flows and flooding, or provide absolute lunar cratering dates over wide areas. We cannot understand the accessible bodies of the Solar System as we understand our own Earth without experiencing them for ourselves.

CUTOUT BOX – FLY ME PERSONALLY TO THE MOON

Space Adventures, the United States firm marketing tourist flights to the Space Station, has signed up Russian aerospace giant Energia Corporation to offer excursions around the moon. In a plan that sounds remarkably like Tim Kyger’s (see the box, What’s Wrong with Air Force Rockets), an upgraded Soyuz would be launched with a pilot and two tourists. It would dock with a separately-launched Energia Block-DM upper stage, which would place the Soyuz into a free-return lunar trajectory. After sailing around the far side of the moon, it would fall back toward a high-speed entry into Earth’s atmosphere.

The cost? $100 million per tourist. Space Adventures believes approximately one-thousand people worldwide have the resources to afford this adventure. For your money, you’ll take on a great deal of personal risk, spend close to a week with two other unwashed bodies in an enclosed space the size of a Volkswagen Bug -- and see close up a world few have ever explored.

Any takers?

Space: the elusive frontier

by

Donald F. Robertson