Selasa, 09 Juli 2019

Buzz Aldrin is looking forward, not back—and he has a plan to bring NASA along - Ars Technica

Buzz Aldrin wants NASA to go somewhere.
Enlarge / Buzz Aldrin wants NASA to go somewhere.
Hubert Vestil/Getty Images

Just after Memorial Day this year, I began talking regularly with the pilot of the first spacecraft to land on the Moon. We had spoken before, but this was different—it seemed urgent. Every week or two, Buzz Aldrin would call to discuss his frustration with the state of NASA and his concerns about the looming 50th anniversary of the Apollo 11 Moon landing without a lack of discernible progress to get back.

Even at 89, Aldrin remains remarkably engaged in the aerospace community, often showing up to meetings and conferences unannounced. Aldrin asks questions. He talks to the principals. In the last two years, the aerospace legend has been to the White House for major space announcements by President Trump, served as an adviser to the National Space Council, and supported the White House goal of returning to the Moon by 2024.

But what NASA has been doing to get back there, for the better part of two decades, just hasn’t been working. President Bush directed NASA back to the Moon more than 15 years ago, and in one form or another, NASA has been spending billions of dollars each year to build a big, heavy spacecraft and a bigger, much heavier rocket as the foundation for such a return. Along the way, NASA has enriched a half-dozen large aerospace contractors and kept Congress happy. But the space agency still can’t even launch its own astronauts into low-Earth orbit, let alone deep space or the Moon.

“I’ve been going over this in my mind,” Aldrin told Ars “We’ve been fumbling around for a long, long time. There has to be a better way of doing things. And I think I’ve found it.”

He realizes that, with a big Apollo anniversary on July 20, this may be one of his last chances to change things. You only hit a Golden Anniversary once, and then it’s gone. And soon, pretty quickly, so are you. So Buzz Aldrin would like to grab the spotlight at this moment, and in the process he hopes to finally get NASA moving forward. He wants NASA to stop trying to repeat the Apollo program of yesteryear and embrace the future of spaceflight.

So as we talked in late May and June, I simply took notes. Aldrin was not speaking to me, after all, he was trying to speak to the world.

Only a few left

Only a dozen humans have ever stepped out of a spacecraft and onto the surface of another world, and two-thirds of them are gone now. Aldrin's partner on Apollo 11, Neil Armstrong, died in 2012. Pete Conrad, Alan Bean, Alan Shepard, Edgar Mitchell, Jim Irwin, John Young, and Gene Cernan have all gone away, too. Most died incredulous—how, they wondered, had the powerful legacy they left behind dissipated like a rocket’s contrail, scattered in the wind?

Of those still left to us, Aldrin is the oldest. Dave Scott, Charlie Duke, and Harrison Schmitt are all in their mid-80s. There is no guarantee any of them will be alive for the 60th anniversary of Apollo 11.

To its credit, the Trump administration has injected NASA with a sense of urgency by setting the 2024 landing goal. In response to this, NASA has proposed the Artemis program, a campaign of 37 launches that culminates with the beginnings of a lunar base in a decade. While there are serious questions about the political saliency of this plan, Apollo 11 astronaut Buzz Aldrin is more concerned about the technical problems.

NASA has spent $50 billion building the Orion spacecraft, Space Launch System rocket, and related exploration vehicles over the past 15 years. Orion is a capable deep space capsule, but it is also massive, weighing 26 tons along with its service module and large heat shield. For every Artemis mission, NASA proposes to launch this mass all the way to the Moon and back. At least Orion is reusable; by contrast the large, expendable SLS rocket will cost more than $1.5 billion per flight and require a standing army of contractors just to keep supply lines open for, at most, a single mission per year.

For all of the time and money invested in SLS and Orion, these vehicles lack the energy to fly a mission into low lunar orbit and back. Indeed, the engine powering Orion’s service module has less than one-third of the thrust of the Apollo propulsion system that flew Aldrin to the Moon in 1969. This is a major reason NASA intends to build a Lunar Gateway—a small space station—in a distant orbit around the Moon. From there, the Gateway will come no closer than 1,000km to the lunar surface and spend most of its seven-day orbit much farther away.

“One thing that surprises me is the lack of performance,” Aldrin said, discussing these vehicles NASA has spent so long developing. “It forces NASA into this weird orbit. And how long is SLS going to last until Blue Origin or SpaceX replaces it? Not long. How long is that heavy Orion spacecraft, with an under-powered European service module, going to hang around in the inventory? Not long.”

Halfway to anywhere

The famed science fiction author Robert Heinlein is credited with saying, "If you can get your ship into orbit, you're halfway to anywhere." The basic gist of this is that, for any space mission, getting off the surface of the Earth and into free fall around the planet consumes half of your energy cost.

For this reason, a lot of aerospace engineers have long argued that deep space missions should be staged out of low-Earth orbit. And as Aldrin has thought about the current state of NASA and private industry, he has come around to this way of thinking, too. He therefore envisions building the “Gateway” not near the Moon but rather in low-Earth orbit. From this gathering point, missions could be assembled to go to the Moon or elsewhere. Aldrin calls this a “TransWay Orbit Rendezvous,” or T.O.R., because it represents a point of transferring from one orbit around Earth to another.

“This T.O.R. plan may be the most important thing I’ve ever done in my life,” Aldrin said.

A near-Earth Gateway would not entirely rewrite NASA’s existing plans. Such a Gateway would include a “power and propulsion” element, which Maxar is already building for the space agency, as well as a habitat module that is also in the works. To this, Aldrin would add three laboratories. One would be a commercial habitat, built perhaps by Bigelow Aerospace or Axiom Space, for space tourism and private research. Another lab would be used for NASA, or other government-sponsored research, and a third one would be a facility to develop and test artificial gravity. International partners could also add modules, if desired.

Positioning the Gateway in low-Earth orbit solves a number of problems for NASA and the White House. The Trump administration has sought to either privatize the International Space Station or move to a “commercial” facility in low-Earth orbit by the mid-2020s. A low-Earth orbit “Gateway” both offers this commercial opportunity and potentially provides a lower-cost replacement for the station, allowing NASA to recoup some of the roughly $4 billion it spends annually on the space station.

Such a low-Earth orbit staging point for deep space missions, or a node, would also allow NASA’s entire Moon program to be flown with existing, or soon to exist, commercial rockets, including the Falcon Heavy, New Glenn, Vulcan, Ariane 6, or other boosters. Why launch the expensive, expendable SLS rocket when much lower-cost, reusable options exist?

Under Aldrin’s plan, NASA would then develop a reusable “tug” to travel between Earth orbit and lunar orbit. Such a cislunar tug could be sized for any mission, ferrying 25 tons or more of cargo—astronauts, landers, fuel, or supplies—per roundtrip. It could be refueled in low-Earth orbit (again, with fuel brought up on reusable rockets) for future journeys. The vehicle could also incorporate an aeroshell to use Earth’s atmosphere as a “brake” when coming back to the planet, thus saving more fuel.

Orion would initially have a role in this architecture, as it presently is NASA’s only vehicle currently rated for deep-space travel. But to get into low-Earth orbit, astronauts would launch instead on NASA’s commercial crew vehicles, Dragon and Starliner, which have about half the mass of Orion, cost less, and are likely to be reusable. The crew would also come home inside the smaller vehicles.

“This plan does not require a big, heavy, inefficient, costly, expendable launch vehicle,” Aldrin said. “Commercial launch vehicles and those under development, that are reusable, can handle pretty much everything.”

Is this possible?

George Sowers, now a professor of engineering at the Colorado School of Mines, used to be the chief scientist for the rocket company United Launch Alliance (ULA). When he worked for ULA, Sowers led the development of a plan for fully reusable in-space stages, fueled by propellant mined and refined in space. It was called Cislunar 1000, because it laid the foundation for 1,000 people working in space.

“Buzz’s plan looks eerily similar to the first few steps in the Cislunar 1000 framework for the commercial development of cislunar space,” Sowers said. “Bottom line, Buzz’s ideas are coherent and technically feasible. In fact, I think the whole community, even some elements within NASA, is starting to get aligned.”

There are some new technologies needed. The principal hurdle is the storage of, and transfer of, chilled liquid rocket fuel. Hydrogen is especially tricky to work with in space, but ULA and NASA have both done some of the basic research needed to prove the technology’s feasibility. One expert working in chilled propellant storage and transfer said that a NASA-funded program with a $250 million budget could produce operational capabilities in less than five years.

ULA has gone so far as to begin design work on an Advanced Cryogenic Evolved Stage, or ACES, that uses hydrogen fuel and could serve as the backbone of such a reusable tug. Jeff Bezos’ Blue Origin rocket company is also doing work in this area.

An overview of United Launch Alliance's Cislunar-1000 plan.

NASA and its contractors have studied these kinds of plans before, and the organization seriously considered the approach about 15 years ago. At the time, Dallas Bienhoff, founder of the Cislunar Space Development Company, worked at Boeing and developed concepts like lunar habitats, propellant depots, space tugs, and more.

Those plans died when then-NASA Administrator Mike Griffin launched the “Constellation” program in 2005, which was characterized as “Apollo on steroids.” This lunar landing plan, centered around a big rocket and Orion, pushed NASA away from an architecture built around cheaper commercial launch vehicles, in-space fuel transfer, and tugs moving between the Earth and Moon. Constellation was canceled just four years later after it fell behind schedule and exceeded its budget, but the basic concept of the Orion spacecraft and a big, expendable rocket lives on today.

While NASA has focused on this Apollo-like approach, advocates of the cislunar tug plan kept tinkering. “Since leaving Boeing, I’ve been promoting a total reusable architecture in cislunar space,” Bienhoff said. Some of the details vary from Aldrin’s concept, but the basic elements are the same: nodes in low-Earth orbit and lunar orbit, tugs moving in between, mining propellant from the Moon and relying on smaller launch vehicles.

Not without a fight

None of the ideas espoused by Aldrin are therefore entirely new, but he instantly becomes the highest profile person in the aerospace community to publicly support them.

But within proper aerospace circles, the suggestion of staging deep space missions in low-Earth orbit has become taboo because so many jobs are guaranteed by NASA’s long-term investments in the SLS rocket and Orion spacecraft. These development programs boast about having suppliers from all 50 states, which ensures widespread support in Congress.

And so while there has been some rabble-rousing around the edges, in mainstream aerospace today everyone more or less accepts NASA’s “big rocket” paradigm that seeks to recreate a Moon program with an Apollo-like approach.

By speaking out, however, Aldrin reminds us that it is never too late to learn new things or adapt to a changing universe in which commercial space offers NASA new opportunities. As Aldrin knows as well as anyone alive today, Apollo succeeded during the 1960s space race at a time when budget didn’t really matter. Now, however, this big rocket model appears to be failing us, especially with the proliferation of cheap US rockets to choose from.

We’ve been flailing around for too long, if you ask Aldrin. There is a need for change, and certainly it is difficult to change programs that have become entrenched in Washington, DC. But an astronaut famed for once punching out a Moon landing conspiracy theorist is not going down without a fight.

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https://arstechnica.com/science/2019/07/buzz-aldrin-is-looking-forward-not-back-and-he-has-a-plan-to-bring-nasa-along/

2019-07-09 11:30:00Z
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