Polar “Lava Tubes”

An abstract at the recent “Landed Science for Landed Missions Workshop” (and subsequent press release) from the SETI Institute claiming the discovery of lava tubes near the north pole of the Moon has gotten a lot of media play.  The problem is that what is being said and written about this “discovery” is wrong on almost every level.  I discuss what’s wrong with it in a new post over at Air & Space.  Comment here, if desired.

Posted in Lunar development, Lunar exploration, Lunar Science | 19 Comments

How Much Water is on the Moon?

I have a new post up at Air & Space that discusses the techniques used to sense water remotely and the amounts of water that may be found in the lunar polar regions.  This post was motivated in part by some of the ignorant comments on lunar water that I see on space chat boards.  Comment here if desired.

Posted in Lunar development, Lunar exploration, Lunar Science | 14 Comments

Inconstant Moon

Moon phase visualization tool from LRO data and the Goddard Spaceflight Center.

I’d like to point readers’ attention to this wonderful visualization tool produced by the Scientific Visualization Studio at NASA Goddard Spaceflight Center and the Lunar Reconnaissance Orbiter Project.  It’s a program that reproduces the Moon’s phase, position in its orbit, distance from the Earth, and libration state.  You can bookmark the page and visit the site to enter a date and time for any time during 2018.  Or you can download an MPEG movie and keep the information on your own computer.

Enjoy!  And  a Merry Christmas and Happy New Year to all!

Posted in Lunar exploration, Lunar Science, space technology | 8 Comments

Humans and Robots — Again

I continue my musings on this perennial topic (and its relevance to the recent Presidential announcement) in a new post at Air & Space.  Comment here, if desired.

Posted in Lunar development, Lunar exploration, Lunar Science, Philosophy of science, planetary exploration, space policy, space technology | 15 Comments

Take a Step on Another World

I have a new piece up at Air & Space on what it will be like to live and work on the Moon.  Comments welcome.

Posted in Lunar exploration, Lunar Science, space policy, space technology | 11 Comments

Are Humans Needed on the Moon?

Apollo 17 LM Pilot and professional geologist Jack Schmitt examines a boulder at the Taurus-Littrow landing site, December, 1972

During my recent appearance on The Space Show, a caller questioned the need for people on the Moon. If teleoperated robots can be used to mine resources, manufacture useful products, and set up a lunar outpost, as I have proposed, why do we even need people on the Moon? The caller’s question touches once again on the age-old argument about the transport and support of humans in outer-space, where their presence is both mass- and power-intensive and thus, more costly. But we shortchange humanity if we fall into the trap of believing that a human presence on the Moon (or in space in general) is either not necessary or that it is only required for making repairs, or for updating equipment.

Now that returning to the Moon is in the news, “Why send humans into space at all?” will be asked, again, as it lies at the heart of a very old debate and battle about space. It is the same question that spawned the 2014 Congressionally mandated study by the National Academy of Sciences. That effort posed two “enduring questions”: How far can humans go and what can they accomplish when they get there? But how can anyone truly know the answers to those questions or make sweeping pronouncements about them? Fortunately, because we’ve had 50 years of human space missions, we have demonstrable evidence about the “usefulness” and promise of humans living and working in space.

In December, we’ll celebrate the 45th anniversary of the Apollo 17 mission of 1972 – the first (and so far, only) mission to fly a professional geologist to the Moon – Lunar Module Pilot Jack Schmitt. The Apollo 17 landing site was a complex, multiple objectives site whose complete and thorough understanding and characterization was not likely within the allotted 3-days there. Nonetheless, Apollo 17 crewmembers Commander Gene Cernan and Jack Schmitt traversed and explored the Taurus-Littrow valley “from one end to the other” (as Gene would say from the Moon), and where they made several significant discoveries. They found highland rocks of extreme antiquity, almost as old as the Moon itself (4.6 billion years). They sampled large boulders that represented the remnants of ancient collisions that created the large, circular mare basins more than 3.9 billion years ago. They discovered orange and black soil at Shorty crater, which later was found to be composed of tiny beads of glass created when lava generated 100s of km deep within the lunar interior erupted and sprayed into space and fell back to the surface. And they collected pieces of material thrown out from one of the youngest large craters on the Moon, Tycho, more than 2200 km distant and whose impact occurred “only” 100 million years ago. Eight hundred and forty pounds of lunar rock and soil samples were returned to Earth by American astronauts over six lunar missions. These samples have given a tangible, invaluable context to scientists studying the Moon remotely, for over 48 years.

Could autonomous machines or those under remote control have carried out this complete and thorough exploration of a complex geologic landing site? Most scientists involved in the Apollo program would argue that machines could not have accomplished what the Apollo 17 crew managed to do. Certainly, scientists studying Mars via rovers have often wished that a thinking, walking and talking human could replace that machine. Productive geological fieldwork requires more than the ability to make measurements and pick up rocks – it is important to sample the right rocks, but also to put visual and mental data into a conceptual framework that guides the geologist toward reconstructing the history and processes of a planet. Of course, “grab samples” can be informative when the site is geologically simple and the rocks have a clear context. An example of this might be collecting samples from the youngest lava flow on the Moon. A scoop of fresh regolith from such a site would most certainly contain chips of lava from that flow, allowing for the determination of its composition, age and the nature of its source region. But complex areas, where comprehensive studies demand a real time, in-depth, working knowledge of complicated geologic “mixes,” require humans who can recognize and mentally process what they see before them.

Fieldwork is a complex discipline, whereby an experienced geologist maps an area and chooses samples – not just rocks picked up at random, but rather carefully chosen – significant and representative samples that inform us about process and history. In any natural setting, literally billions of bits of data could be collected. And that’s what a machine does – it collects data. A human field scientist also collects data, but they also are able to high-grade it by collecting only the most significant and relevant data. It takes extensive study, then training and experience in the field, to be able to recognize the significant and distinguish it from the trivial – to see the big picture. We often remark on the Mars Exploration Rovers for their accomplishments, yet for all the data collected, we still cannot draw a simple geologic cross-section of those landing sites, and we still do not know the origin of many of the rocks at the site (igneous or sedimentary). A human geologist would have obtained this important information after a few hours of fieldwork. The mass- and power-intensive humans give a big return on their investment.

In addition to fieldwork, humans possess other qualities that machines do not. The ability of people to recognize, diagnose and solve equipment malfunctions has been proven time and again throughout the history of the space program. The Apollo 17 crew not only explored the valley of Taurus-Littrow, they also deployed an experiment package that required careful installation and alignment. They fabricated and replaced the fender of their lunar rover by using the famous stand-by of all terrestrial repairmen, duct tape and plastic maps (if the rover fender had not been replaced, the dust kicked up by the rover wheels would have soon coated all electronic equipment, leading to overheating and termination of the surface exploration). During the Skylab program (1973), repair work by the crew saved the crippled space station after it was damaged during launch. Literally heroic efforts by Pete Conrad and his crewmates Paul Weitz and Joe Kerwin allowed not only habitation of the overheated Skylab, which was then used by two subsequent crews, but literally saved the entire program. When it was discovered after launch that the mirror of the Hubble Telescope had been ground incorrectly, the crew of Shuttle Mission STS-61 were sent on a mission to put corrective lens on the telescope, again saving the entire program. The assembly and numerous repairs and maintenance of the International Space Station (ISS) require the use of both human and robotic assets to complete, without which the program certainly would not have survived. And this new era in space spawned an explosion of engineers and scientists, and dominated our culture with space movies, architecture, fashion and technology.

Fortunately for humanity, people are required in space to do what only people can do (while also dreaming up new things to do and new ways to do them) – tasks requiring experience and knowledge guided by reasoned judgment and imagination. The ability to act and then learn from such action is critical. People will always innovate solutions for seemingly intractable problems that may arise. A combination of fine-scale manual dexterity and expert, informed knowledge and the ability to react, creates an ease of capabilities in space unachievable by machines alone. The template created during the assembly of the ISS – in which people using robotic machines assembled a complex spacecraft in orbit – is the most likely and productive path for future space activity of all kinds.

Do we need people on the Moon? Fortunately, the answer is a resounding “Yes!” Humans bring unique capabilities that are needed to accomplish new things – unknowable things, things that will enhance our lives on Earth. Studies that conclude that only robots should conduct space and surface operations – as people require protective equipment and habitats – is shortsighted and harmful to a vibrant, intelligent, and inquisitive society. Both humans, and the machines they create to assist them, are required for success in this grand adventure.

Posted in Lunar exploration, Lunar Science, Philosophy of science, planetary exploration, space policy, space technology | 23 Comments

Jack Schmitt’s Lunar Memories

The famous night launch of the Saturn V carrying the Apollo 17 spacecraft on December 7, 2017

Apollo 17 Lunar Module Pilot and Geologist Harrison H. (Jack) Schmitt has posted a new item on his web site: the beginning of a reminiscence of his historic flight, which departed for the Moon 44 years and 11 months ago today (December 7, 1972).  Although only one chapter is posted so far, it is a great read, describing the busy last month of training, simulation and constant work before the launch of an Apollo crew.  I urge readers of this blog to visit his site and enjoy Chapter 4 – Thirty Days and Counting…  I eagerly look forward to the next installment.

On a related note, my good friend Bill Mellberg, who passed away this year, wrote an essay recalling his attendance at the launch of Apollo 17 (which includes a guest appearance by Wernher von Braun).  Bill’s essay can be found at Jack’s web site, HERE.

Posted in Lunar exploration, Lunar Science, space technology, Space transportation | 4 Comments

Why We Go To The Moon – A Mission Statement

I have a new blog post up at Air & Space on the need for a “mission statement” for our return to the lunar surface.  I advocated this during the VSE days, but lost that argument.  I believe this to be an important issue — previous NASA efforts at lunar return were marked by confusion and aimlessness.  Please comment, if you feel so inclined.

Posted in Lunar development, Lunar exploration, Lunar Science, Philosophy of science, space policy, space technology, Space transportation | 17 Comments

Flight of the Space Turkey

The new Orion spacecraft — Cadillac or Edsel?

Throwing a wrench into NASA’s engine of progress may not have been the intent of Vice President Pence’s first meeting of the National Space Council with his announcement that a human return to the lunar surface is the new direction for America’s human spaceflight program. But a wrench it was and will remain until pieces of the formerly touted “Journey to Mars” – the heavy lift SLS launch vehicle, the Orion spacecraft, and a relatively recent addition, the Deep Space Gateway (DSG, a small human-tended space station in a distant orbit around the Moon) – are reimagined and torqued into the new strategic direction.

Much venom has been hurled at the SLS launch vehicle, largely on the grounds of its alleged cost and its origins as a “government rocket” (i.e., “pork”). But heavy lift launch capability is extremely useful for the emplacement of a substantial cislunar infrastructure. Heavy lift permits the launch of large and/or multiple vehicles and facilities all at one time, and that makes the coordination of their arrival and assembly at a selected trans-LEO destination easier. The core SLS vehicle delivers 70-80 metric tones to LEO, more than enough to put about 10 tones on the lunar surface, or 15-20 tones into low lunar orbit. In addition, a large rocket also offers a large shroud diameter; volume can actually be more critical than throw mass for large architecture pieces like big landers and habitat elements. Technically, the SLS is a good fit for any future lunar return architecture.

The main argument against the SLS is its cost, but current estimates of $1-2 billion per launch are based primarily on the low projected flight rate planned by the previous program of record, which called for very few missions. A faster pace of a lunar surface return could bring these costs down, although they would still be in the range of multi-hundreds of millions of dollars per flight. If the long-promised and long-awaited commercial heavy lift vehicle eventually emerges, this estimate of cost – and the choice of a heavy lift launch vehicle – should be re-evaluated (but not until then).

The Deep Space Gateway (DSG) is an idea that comes from a variety of architectural studies that looked at the use of a staging node placed beyond LEO – well outside of Earth’s gravity well, for a human Mars mission. Initially focused on the Earth-Moon Lagrange Points, subsequent studies converged on something called a Near Rectilinear Halo Orbit, a complex path around the Moon that is relatively stable (requiring little orbital maintenance propulsion). The orbit selected for initial study is quite far from the Moon, up to 70,000 km distant. While this distance may make a good staging orbit for a departing Mars mission, it cannot easily support missions to low lunar orbit or to the lunar surface – the new strategic direction (delta-v to the surface from this orbit is near lunar escape velocity, ~2400 m/s).

In our published architectures (Spudis-Lavoie – Using the resources of the Moon to create a permanent, cislunar space faring system (2011) and Lavoie-Spudis – The Purpose of Human Spaceflight and a Lunar Architecture to Explore the Potential of Resource Utilization (2016), a propellant depot/transfer node is placed in low lunar orbit to keep the lunar lander transport a single-stage-to-orbit (SSTO) vehicle, making the lander completely reusable. Moving the node point to the Earth-Moon L-1 point costs roughly an extra 800 m/s in delta-v. Our lander design is already challenged with the requirement of re-usability (mostly propulsion system concerns: multi-start use lifetime, with little to no maintenance) and by having an engine-out capability to provide reasonable abort scenarios. Other design considerations include extreme temperature variations (thermal cycles) and parts fatigue, which results in higher subsystem mass than a single-use lander. All of these factors lead us to place the depot/node at the lowest reasonable point in orbit around the Moon, ~100 km circular. Orbital maintenance is on the order of 500 m/s/yr, which is achievable for the depot. After initial operations, the depot/node can change its orbit to a more advantageous one should future lander designs prove more capable.

Properly reconfigured, the DSG could serve as a low lunar orbit habitat-depot-node. This would require re-thinking its mission (fuel depot in addition to habitat) and its thermal design, because low lunar orbit can be quite warm on the daytime side of the Moon. The “lumpiness” of the uneven lunar gravity field (mascons) makes low orbits unstable and considerable propulsion is necessary to maintain it. However, we now have lunar gravity maps of extraordinary quality that reveal “frozen orbits” – ones where virtually no orbital maintenance is required (the currently operating LRO spacecraft is in such a frozen orbit). Use of these orbits would need to be traded against accessibility and lander energy cost, but in any event, a propellant depot would possess more than adequate propulsion for orbital maintenance. Finally, and most importantly, a station in low lunar orbit is well placed to support operations in space and on the lunar surface.

If both the SLS and the DSG could be adapted to the requirements of lunar surface return, what about Orion? Consider this: Orion was originally conceived as a component of the Constellation spaceflight system; it was designed to transport people to and from the Moon in a manner similar to the Apollo spacecraft. In short, this was a mission launched “all up” from Earth, with pieces discarded after use along the way. In the case of Constellation, two vehicles, Ares I and V, would launch the Orion and the Altair and transfer stage, respectively. The two vehicles would dock in low Earth orbit and depart for the Moon. Burning into lunar orbit, the crew would transfer to the Altair lunar lander and descend and land on the Moon for a period of a couple of weeks. After exploration of the landing site, the crew would ascend to the orbiting Orion and transfer into it for their journey home. The Orion spacecraft would discard its service module and re-enter the atmosphere at near-escape velocity, splashing down in the ocean for recovery. At each step in the above mission sequence, parts are discarded and not reused, requiring high levels of funding and leaving little, if any, hardware in space as legacy infrastructure.

When the Constellation program was cancelled in 2010, Orion was the only piece preserved, largely because at the time, it was the only spacecraft capable of sending American astronauts into space. However, without its Altair lander, Orion was no longer a lunar spacecraft system. It instead became a vehicle whose only purpose is to send crew into trans-LEO space and allow them to return to Earth with aero-thermal entry. It can support a crew of four, for periods of a couple of weeks, but cannot last much longer. It is for this reason that the ill-conceived Asteroid Retrieval Mission (ARM) concept was born – designed to give Orion someplace to go and something to do. Despite the fact that the ARM was nearly worthless scientifically and operationally, it was a mission configured to the capabilities of the Orion spacecraft. To support this scaled back mission profile, the current edition of the Service Module for the Orion (built by the Europeans) is smaller than the previous edition under Constellation. Unfortunately, that also means that the Orion can get into (but cannot then get out of) low lunar orbit, taking from Orion what little value it had for a possible lunar mission.

Where does that leave things as NASA contemplates lunar return? We currently have three pieces of space hardware, each configured to support a vaguely defined series of missions to deep cislunar space. The SLS can be adapted to transport all the pieces we need to establish and operate an outpost on the Moon. The Deep Space Gateway can be modified to operate in low lunar orbit, making it a possible staging node for trips to and from the Moon’s surface. But that still leaves us with Orion. True enough, crew members leaving the Moon will need a way to return to Earth, but if a permanent outpost is established there, we need to develop a reusable system that transports crew and cargo to and from low Earth orbit on a recurring basis (a reusable cislunar transfer stage). Such a vehicle would fire a rocket to accelerate out of LEO into a translunar trajectory. Approaching the Moon, it could burn into and out of low lunar orbit, delivering crew and supplies to be transferred into the lunar lander vehicle. On the way home, rather than direct entry and landing on Earth, it would aerobrake (i.e., use Earth’s atmosphere to slow the vehicle from escape velocity to orbital velocity) into Earth orbit and rendezvous with a transfer node in LEO. Here the crew would transfer to a commercial vehicle for return to Earth. All of these systems have been envisioned, at least conceptually, by a variety of published architectures over the last decade.

But can Orion be repurposed? In contrast to most informed opinion, I believe that of the three major human spaceflight pieces described here, Orion is the one that is the least useful and most likely to vanish. This should not be too surprising, considering that it is an orphaned, smaller piece of a larger system designed to return people to the Moon. Yet work continues on Orion, heedless of any possible change in mission – and has done so throughout the last 8 years as its mission gradually morphed from Moon-Mars spacecraft, to an asteroid spacecraft, to a “Space Station in Deep Space” spacecraft. This bureaucratic resilience suggests that setting Orion aside is a nonstarter – contractors and Congressional advocates may insist on its continuation, in a manner similar to the SLS “lobby,” which assured continuity of that development program.

Ideally, one would design a return to the Moon using a clean sheet, focusing on early robotic presence and a series of newly imagined, modular, reusable space-based human assets. However, we do not live in that world. So the question is how to “MacGyver” what we have to get what we need. Listed in order of decreasing usefulness, SLS, DSG and Orion can all be used in a lunar return. The SLS provides us a way to get large, heavy payloads to the Moon. The DSG, while not currently configured to support lunar surface activities, could be modified to do so without too much re-design. The Orion could be used for early human flights to the DSG – establishing a human presence near the Moon, while robots would do much of the early resource prospecting and processing work on the surface. After human return to the lunar surface, Orion could be docked at the DSG and serve as a “lifeboat” vehicle in the event that emergency circumstances require the outpost crew return quickly to Earth.

From Super-Apollo to crew assured-return vehicle – a diminished ending to a once-noble vehicle development? Possibly. It depends on your point of view. As it currently exists, Orion is not a particularly useful spacecraft. But if we use it to help establish a permanent human presence on the Moon, it will have served a noble purpose indeed.

Posted in Lunar development, Lunar exploration, space industry, space policy, space technology, Space transportation | 26 Comments

A Pioneering NASA Administrator

I have new post up at Air & Space discussing the “Pioneering Doctrine” devised by Rep. Jim Bridenstine as part of his American Space Renaissance Act (ASRA).  Although not yet a passed law, this doctrine is informative about his thinking on the rationale and strategic objectives of our national space program.  Comment here if desired.

Posted in Lunar development, Lunar exploration, planetary exploration, space industry, space policy, space technology, Space transportation | 15 Comments