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Lost glory?

Miles O’Brien, late of CNN, recently wrote a column reflecting on the accomplishment of the Apollo program and the space program since then.  He believes that Apollo was a great leap forward in space, a capability and step from which we then walked away.  O’Brien asks why the country has turned its back on the promise of space and what it will take to re-establish the resolve we once showed in reaching for the Moon.

These thoughts are common enough in the space community.  Why doesn’t the nation see the conquest of space as critical?  Why didn’t wonderful accomplishments of the Apollo program propel us onward to the planets?  Why do we continue to condone a space program of such apparent mediocrity?

None of these questions are the right ones because they misunderstand the true purpose of Apollo.  The O’Brien column is only the latest in a long series of missives that long for a new renaissance of space travel, to pick up the mantle of space greatness promised by Apollo but abandoned afterwards.

Apollo was not about the Moon, or even about space.  It took place in space and ultimately, on the Moon.  But Apollo was a battle in the Cold War.  John Kennedy did not say, “Go to the Moon and press onwards to the planets.”  He challenged America to show the superiority of its economic and political system by landing a man on the Moon and returning him to Earth “before this decade is out.”  The key objective was not going to the Moon – it was to beat the Soviets to the Moon.  This objective was attained with profound consequences, critical to our Cold War victory to a degree still not fully appreciated.

Most space program observers acknowledge this distinction, but they have only accepted it intellectually, not emotionally.  To them, Apollo was a miscarriage of Wernher von Braun’s dream of interplanetary flight.  Indeed, von Braun himself thought this.  As a firm believer in large engineering projects in service of national goals, he was willing to postpone his incremental, stepping stone architecture to the imperative of reaching the Moon before the Russians.  But after the battle was won, he wanted to return to the classic, sequential framework he had always advocated: shuttle, station, moon tug, Mars craft.

The political will for such a program did not exist then and doesn’t exist now.  We stopped going to the Moon for a very simple reason – after you win a battle, you don’t keep fighting it.  We beat the Soviets to the Moon – the reason for Apollo’s existence.  It required a significant fraction of the national wealth to pull off the Moon landing (at peak, almost 7% of the federal budget was spent on Apollo) along with the personal commitment of thousands of engineers and technicians across America, many of whom destroyed their marriages working double hours and weekends to meet tight deadlines.  This kind of effort on behalf of a government program is not expended lightly; the Apollo program had the mentality of a war effort.  And indeed, that’s exactly what it was.

So what does this mean for our future?  Has America lost its way?  Is it simply that we no longer dare to do great things in space?  I think not.  What’s needed is a space program that doesn’t require an industrial war footing.  The opportunity given to NASA called the Vision for Space Exploration tried to foster a return to the Moon using small, incremental and cumulative steps.  Such a program is congruent both with fiscal realities and with our aspirations to explore.

Miles O’Brien challenges us to drum up a heightened level of public enthusiasm, one that would support a new program that rivals Apollo in scale and ambition.  But the experience of the last 30 years shows that in the absence of a credible external threat, the fiscal and human cost of such a space program is simply more than America is willing to pay.

I argue that the challenge for space advocates is to craft a program that matches the level of public support.  Much can be done with existing resources if they are obtained and deployed in a rational and ingenious manner.  Humanity instinctively gravitates toward exploration.  People sense that engaging in these pursuits is about much more than politics, diplomacy or prestige.  It’s about human survival.

Are we willing to build a lasting spacefaring infrastructure – to change wartime resolve and bravery into an enduring legacy of human achievement?  If so, the greatest days of our space program may yet lie ahead.

Mini-SAR image strip near the lunar south pole

The first images obtained by the Mini-SAR radar instrument aboard the Indian Chandrayaan-1 spacecraft, currently orbiting the Moon, were released yesterday.  Although the spacecraft arrived last November, we are only now getting ready to map the poles of the Moon.  The data released are test images, designed to make certain the instrument is working properly, that we can command it properly and that the end-to-end data stream from the Moon is configured correctly.

Imaging radar works by sending a series of pulses which hit the Moon and are reflected back to the spacecraft.  The range to the surface (measured by the time lag between send and receive pulses) and velocity of our instrument relative to the target (indicated by the slight Doppler shift in frequency) are determined and stored as data.  These data are sent down to Earth, where we reconstruct the information into an image that shows the radar reflectivity of the Moon’s surface as a function of position.  The result appears similar to an optical image but is very different.

Unlike a photograph, radar provides its own illumination – the pulses sent to the surface are reflected, received back and converted into an image.  It is this effect that allows us to “see” into the permanently dark areas near the lunar poles.  Another difference is that  radar images slightly penetrate the lunar surface to illuminate and image the subsurface structure.  The depth of penetration depends upon the wavelength of the radar system, typically a few tens of wavelengths.  In the case of Mini-SAR, our wavelength is 13 cm and we are looking into the Moon to depths of about 1 to 2 meters, the uppermost portion of the lunar regolith.

Our objectives are to map the poles of the Moon, examining the permanently dark areas and characterizing their surface properties.  These dark areas never see sunlight and are extremely cold, only a few tens of degrees above absolute zero.  Because the Moon is bombarded with water-bearing objects such as comets, we think it is possible that water might be trapped in these dark zones near the poles.  Radar is reflected from various surfaces in different ways.  The reflections from rock and soil are very different than those from ice.  By mapping all the dark regions and determining their surface backscattering properties, we hope to identify any possible ice deposits, even though they cannot be seen with visible light.

The image released shows the interior of the lunar crater Haworth, a 35 km diameter feature just north of the crater Shackleton, at the south pole of the Moon.  Because Haworth is both deep and partly shielded by the bulk of Malapert Mountain just north of it, its floor is in both Sun shadow (never being illuminated by the Sun) and in Earth shadow (meaning that radar from Earth-based radio telescopes cannot see into it).  Mini-SAR has given us our first look into the dark interior of this crater.  We see that it has a relatively flat floor, with numerous other craters formed on it.  We have not yet analyzed its backscatter properties, but the data are of sufficient quality that this analysis is possible. The first Mini-SAR images mostly show that the instrument is working properly.  Future collects will image large, contiguous areas and gather high fidelity information that will allow us to identify and map the extent of anomalous reflective properties.

Despite some sensationalistic and inaccurate news reporting, we have not yet found any deposits of ice, or even any “extremely hard surfaces.”  (By the way, hard surfaces are not absent from the Moon – they can be found wherever bare rock is exposed, for example, in outcrops along crater and rille walls or the surfaces of very young features, like the solidified pools of shock impact melt in King crater). I’ve been down this road before:  a quick look at some data, someone shoots off their mouth, and the press takes it from there.  Not this time.  If we find something interesting, we will repeat our observations, probably several times, to make sure that the data is good before any interpretations are announced.  So beware of what’s reported in the news.

I am very pleased and excited to get new data from an instrument never before flown to the Moon.  I’m looking forward to the next few months, when we’ll get our full allocations of mapping time to build up our polar mosaics.  The search for lunar ice has only just begun.

A Postscript

Emily Lakdawalla has noted the public release of Mini-SAR images on her blog at The Planetary Society. She seems somewhat disappointed in the appearance of the images, noting that they seem “less crisp” than other SAR images she has seen. She attributes this lack of “crispness” to the smoothness of the Moon itself (features being eroded by the constant rain of micrometeorites) and to the compact miniaturization of our SAR instrument (Mini-SAR is less than 10 kg in mass, smaller than any previous space radar).

Neither explanation is correct. The principal reason for “crispness” of SAR images is the presence of cast shadows. Mini-SAR uses an incidence angle of about 35 degrees; as one of our main objectives is to search for ice on the Moon, we chose this imaging angle deliberately to enhance the backscatter signal from the surface, making the identification of ice easier. In fact, for our purposes, cast shadows are not desirable because we want to map all of the dark areas near the pole — a cast shadow represents an unmapped area.

It is difficult to judge context from a narrow strip image.  As we build up our contiguous mosaics of the poles, the radar images should be easier to examine and interpret.

It would appear that we are in the midst of yet another attempt to define the goals and objectives of our national space program. This time, the National Academy of Sciences is conducting a study on the Rationale and Goals of the U. S. Civil Space Program. After completion, this study will no doubt be consigned to the large pile of previous studies gathering dust on the bookshelves of space students everywhere.

The study group is asking for public comment and input, in 600 words or less. This is what I have submitted:

The U.S. space program must serve national scientific, economic and security interests. Science has been well served by the space program and space exploration has revolutionized understanding of the universe and our place in it. Commercial opportunities in space have followed paths blazed by government, including launch services and operations in LEO to GEO Earth orbit. The next goal should be to expand the extent and capability of human “reach” beyond this zone first into cislunar and then into interplanetary space.

The ultimate object in space is to go anywhere, at any time, with whatever capabilities needed to do any task or objective. This ability is still far away; current spaceflight opportunities are mass and energy limited and will always be so if everything needed in space must be lifted from the deep gravity well of Earth’s surface. To create greater capability, the resources of space must be harnessed to build, extend and operate a transportation system in space. The initial goal is to create a permanent infrastructure that can routinely access the entire volume of cislunar space (where all current space assets reside) with machines and people. As capabilities grow with time, such a system would be extended to interplanetary space.

To this end, the goal for next couple of decades should be to learn the skills and acquire the technologies needed to use the material and energy resources of space and to access, inhabit and work productively on the surfaces of extraterrestrial bodies. The Moon is the first target for research and use. It is both a school and a laboratory to learn how to get to, live on and explore other worlds. This task requires extended (ultimately, permanent) presence on the Moon with both machines and people.

Reconnaissance to explore, map and characterize work and habitat sites on the Moon can be done with robots and teleoperated machines. Demonstration experiments should be conducted to explore resource extraction techniques and processes, handling of materials, and create expanded capabilities and to emplace assets prior to human arrival. People will extend these capabilities and use the new infrastructure to understand the trade-offs, paybacks, difficulties and choke points of various resource extraction options. Humans will learn how to emplace, operate, maintain and expand planetary surface habitats.

A permanent human presence on the Moon creates new and exciting scientific opportunities. The Moon is a complex, miniature planetary body and preserves both its own history and – uniquely – Earth’s early history. The Moon records the output and history of our Sun and high-energy galactic particles for the last 4 billion years. Its surface environment enables the construction and emplacement of unique observational systems that can map in unprecedented detail the Earth and its environment, the local space neighborhood and the universe beyond.

To become a true spacefaring nation, the “umbilical cord” of space logistics must be cut to create a permanent, flexible and extensible transportation and habitation infrastructure beyond low Earth orbit. It is a difficult task, appropriate for government technical and financial support. It will open up the frontier of space for many and varied purposes, the fundamental objective of American space policy.

Please feel free to go and add your own two cents at the web site above. If repetition really is the mother of learning, perhaps we can repeat ourselves enough so that eventually, the right thing will be done.