Decision day is looming to choose NASA's heavylift booster to power its space exploration initiative – its choice will dominate the agency's spending for decades

Next month, NASA faces its biggest decision since the launch of the Apollo programme when it is due to select a heavylift booster for its space exploration initiative. The agency must choose between a derivative of the Space Shuttle and development of existing expendable launch vehicles.

The decision to develop a heavylift launch vehicle will create one of the biggest single line items in NASA's budget for this decade and into the next, and risks dragging the agency's exploration plans into a spiral of delay and overspending.

The heavylift decision stems from the US vision for space exploration outlined by President George Bush last year. After the Space Shuttle Columbia disaster in February 2003, Bush decided that if humans were to undertake such a dangerous feat as spaceflight, they must go to the Moon and Mars to make big scientific discoveries, not just go into Earth orbit.

Now details of what returning to the Moon means and how it will be done are becoming clearer. Key to the heavylift choice is how NASA intends to send astronauts to the Moon.

By 2020, crews of four astronauts are expected to be sent to the Moon's south polar region for extended stays, initially for two weeks and then for many months as NASA develops the capability for a Mars mission. The Moon base will operate like an Antarctic research station, with astronauts conducting lunar and cosmological scientific activities.

Contractors have been told to plan for one manned Moon mission a year, with missions from 2015 to 2020 slowly building up the Earth to Moon infrastructure. Eventually the lunar habitat and supplies will be in place for astronauts who will use the Crew Exploration Vehicle (CEV) to reach the Moon.

The CEV is intended to weigh a maximum of 20t (44,000lb), a mass that can already be put into low Earth orbit (LEO) by Boeing's Delta IV Heavy launcher. The CEV will reach the Moon using an Earth Departure Stage (EDS) and, once in lunar orbit, the crew will use the Lunar Surface Access Module (LSAM) to reach the south pole base. It is the EDS and LSAM that will require the heavylift vehicle.

The CEV and EDS will be launched separately because, after two Shuttle disasters, NASA decided not to send crew and cargo up at the same time. The CEV Launch Vehicle (CEVLV) will therefore be separate from the heavylift launcher. The EDS launcher is referred to as the Cargo Delivery System (CDS).

Because crew and cargo will travel separately, in-orbit docking between the CEV and the EDS and LASM assembly will be needed. This is an important consideration because launching and landing are the two most dangerous phases of any space mission. Minimising the number of launches will be at the heart of the decision on the CDS launch vehicle.

Craig Steidle, associate administrator for NASA's exploration mission systems directorate, says the three main factors in the heavylift decision are the launch pad infrastructure, the need for new technology and the expected development cost. But the number of launches required and the complexity of docking operations in orbit will also be a major consideration.

Two launches

With a Shuttle-derived launch vehicle (SDLV), everything can be put into orbit with two launches – one for the EDS and LASM and one for the CEV. Options using the Boeing Delta IV and Lockheed Martin Atlas V evolved expendable launch vehicles (EELV) could require three, five or more launches. Rendezvous and docking of Moon or Mars ship segments is a major operational hurdle.

Another factor is the new White House Space Transportation policy, published in January, which maintains the US Department of Defense's (DoD) responsibility for the EELV programme. To develop a heavylift derivative of the EELV, NASA would have to work with the military.

Then there is NASA's budget. In its FY2006 request, the Bush administration has asked Congress for a 2.4% increase to bring the agency's budget to $16.45 billion, almost $386 million more than in FY2005. But the hike faces heavy political opposition because almost all other US government departments are having their budgets frozen. Assuming NASA's budget is approved, funding for developing a heavylift launcher would have to come from the Constellation Systems budget line. For 2005 that is only $526 million, rising to $2.4 billion in 2010. However, that also has to pay for the development of the CEV and its launch vehicle.

Limited funding and probable huge development costs have already led NASA to reject the idea of developing an entirely new heavylift launch vehicle. Some observers feel the decision to use existing technologies is one reason why an SDLV holds sway over an EELV development.

The Space Shuttle, its external tank and solid rocket boosters (SRB) have been in operation since 1981, providing a 27t-to-LEO capability. There is also a vast infrastructure of launch facilities and companies providing hardware and services.

"There is a lot of momentum and some political support for keeping the Shuttle going," says Steve Oswald, former Shuttle astronaut and Boeing's Shuttle programme manager. "The problem with the Delta IV is it's only a quarter of what you need and you have to get it up to 42t at least."

At a NASA/industry technical interchange meeting in February, a 70t-to-LEO SDLV configuration with side-mounted cargo vehicle was selected for further study. During the same week, at an American Institute for Aeronautics and Astronautics (AIAA) space exploration conference in Florida, several SDLV launcher models were displayed, showing that the Shuttle is still big business and its continued operation, even in an altered form, is attractive to shareholders.

"Both Boeing and Lockheed Martin stand to win with Shuttle-derived," says Washington-based Space Policy Institute research professor Ray Williamson, "and there is a whole slew of subcontractors."

Despite this momentum behind the SDLV, the Shuttle's operating costs have always been huge. NASA, which has always been vague about costs, suggested dividing the annual Shuttle budget by the number of missions in a year. In 1994 Roger Pielke, now director of the University of Colorado's Center for Science and Technology Policy Research, did just that and came up with a figure of $1.6 billion per launch in 1992 dollars. Now Pielke estimates the launch cost to be similar in today's dollar value.

NASA insiders say EELV contractors gave a heavylift launch price of $250 million for a 20t-to-LEO capability during recent CEV discussions with NASA.

EELV supporters say the SDLV is a space exploration-only vehicle and no use for commercial and military satellite launches. They claim that, unlike EELV with its many potential customers, NASA would have to bear the entire cost of an SDLV.

The EELV programme was created by the DoD to ensure its access to space after the Challenger Shuttle disaster. The DoD has provided EELV prime contractors Boeing and Lockheed Martin with more than $500 million a year for several years to ensure it has two different launch vehicles available. The new White House space policy ensures this will continue.

Biggest bang

Boeing launched the most powerful version of its EELV so far, the Delta IV Heavy, last December and proposes evolving the vehicle further for space exploration. "Only modest upgrades would be needed; it would be the cheapest, biggest bang for the buck," says Frank Slazer, Boeing Launch Services' director for NASA/civilian space business development. "We could get to a 38t-to-LEO capability just by adding six SRBs to the Delta IV Heavy. And you wouldn't notice the changes we would make to the launch pad."

Existing launch pads, wider commercial application and support from the DoD could work in favour of the EELV heavylift option. Yet the existing Shuttle infrastructure, the political significance of the jobs that rely on the Shuttle programme and the fact that industry experts consider SDLV a win-win scenario for both Boeing and Lockheed Martin mean the Shuttle-derived solution could still succeed.

It is because of the Shuttle that NASA's heavylift decision is being made as early as April. A decision in favour of the EELV will require an immediate start to the managed shutdown of Shuttle infrastructure because the vehicle is planned to be retired in 2010 after assembly of the International Space Station is complete.

Until then, Congress is unlikely to allow NASA to spend more than its projections. Just-departed NASA administrator Sean O'Keefe warned the space industry at February's AIAA conference that manned exploration beyond LEO could easily be over for another 50 years.

"We can't return to the days of the Saturn V," he said. "We don't need to do it that way. If you do, we will be doing it for a couple of years and then it will wane like it did in the 1970s."


Source: Flight International