The Douglas ASTRO: An Air Force Launcher

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The ASTRO, as pictured in the September 3, 1962 issue of Missiles and Rockets. Image artist unknown and copyright status uncertain, but believed to be in the public domain. Via the Internet Archive.

What it was: A lifting body craft proposed to the USAF by Douglas Aircraft. It would initially be used as a suborbital trainer then, after up-scaling and being paired with a second lifting body in an unusual nose-to-tail arrangement, evolve into a fully reusable vehicle with a nine-tonne payload capacity to LEO.

Details: In late 1962, the USAF was on the cusp of deciding how it would go forward with its plans to put military men in space. The X-15 had made its first flight mid-year, and the X-20 program was ramping up. Doubts about the latter were getting stronger, though, and would ultimately result in the Air Force deciding to work on the Manned Orbiting Laboratory instead.

It was at this point that an article was published in the now-defunct Missiles and Rockets magazine outlining a proposal from Douglas Aircraft that was supposedly being evaluated by the USAF. What it outlined was a two-part development program that would check the usual laundry list of military applications for space as perceived in the early 1960s.

The core of the ASTRO (Advanced Spacecraft Truck/Trainer/Transport Reusable Orbiter) was the answer to a question the USAF had proposed to North American Aviation and Douglas, as well as Boeing, Vought, and Republic: how to train pilots for the X-20 on actual flights prior to the X-20 being built. North American had come back with what they called the STX-15, which was a way of reconfiguring an X-15 to have the projected flight characteristics of an X-20 (except for, of course, the highest speed and orbital parts). The Phase I of Douglas’ ASTRO was their significantly more ambitious counter to the NAA proposal.

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A schematic of the ASTRO’s A2 vehicle, which would be both independent for suborbital hops, or be boosted to the point that it could be lifted into orbit by a derivative of the same vehicle. Note the booster nose’s ghostly presence at the far right of the image. Same source as previous. Click for a larger view.

Unfettered by the previously existing X-15, Douglas wanted to build a completely new craft dubbed A2, which would be capable of suborbital hops of about 5000 miles (8000 kilometers) after taking off from a runway under the impetus of a J-2 engine, the same rocket engine used by the Saturn V’s second and third stages. Pilots would get their space training, the USAF would have themselves a reusable vehicle with intercontinental range which could carry ten people, or a similar amount of payload. Two RL-10s, as used on the Centaur, would provide a little extra oomph.

Phase II was where Douglas diverged from the question being asked. Take the A2, modify it so that it only carried one crew and two extra J-2 engines, then stick it nose to bumper on the end of another A2 built to the Phase I spec. Turn it 90 degrees and launch it vertically, with the two separating from each other at altitude and speed (both unspecified). The sole crew member aboard the booster would glide back to Earth, while the uppermost A2 would ignite its engines, hopefully after allowing a bit of distance to build from the booster, and carry on into orbit. Douglas projected two crew and about a tonne of cargo to LEO in this configuration.

Phase III scaled up the booster, now dubbed B, and equipped it with two J-2s and one M-1, a never-built LH2/LOX engine that dwarfed even the F-1 engines used on the Saturn V’s main stage. Also launched vertically, this would be the ultimate version of the craft.

The full, two-stage Phase III vehicle was to have been 159 feet long (48.5 meters) and while mass was not mentioned the propellant capacity of the stages (165,000 pounds for the A2 and 594,000 pounds for the B) are—this suggests a total loaded vehicle mass at launch of about 380 to 400 tonnes. Total payload, as mentioned previously, was about nine tonnes, including crew, and there’s a sign that Douglas was nervous about this: the article specifically mentions wanting to launch due east from the Equator, which is an odd thing to be suggesting in 1962, well after the US had committed to launching from the continental USA.

If built, the program was expected to run from 1964 to 1970, with the first flight of the Phase III craft at the end of that period.

What happened to make it fail: It’s difficult to fit the ASTRO into the chronology of the X-20. Phase I appears to have been an attempt to come up with a “Gemini” for the X-20’s “Apollo”, giving the USAF the capability of sending pilots on long suborbital jaunts to train them for the environment they’d encounter when aboard the fully orbital X-20. Phase III would then have been a follow-up to the X-20, increasing crew capacity and payload over that craft.

If this is the case, then, it explains why the ASTRO never went anywhere. The craft made its sole notable public appearance in September of 1962, and American Secretary of Defense Robert McNamara was definitely thinking about cancelling the X-20 no later than March 1963—and possibly earlier. When the X-20 was stopped, then ASTRO would go with it. This is particularly true if one assumes, as seems likely, that the USAF was never very warm about the idea at all, and that it primarily existed as a pitch from Douglas leaked through Missiles and Rockets magazine to drum up support. There’s essentially no reports or discussion of ASTRO post-dating the magazine’s unveil.

What was necessary for it to succeed: It’s not easy to see a way forward for this one. X-20 was dead in the water less than six months later (eventually being formally cancelled in December 1963), and the payload capacity of even the Phase III ASTRO was marginal for what would have been an expensive program. There’s also the issue of Douglas vastly exceeding the question posed by the USAF—it’s unclear that there was any interest on the part of the Air Force in anything other than Phase I. This in turn defeated the purpose of building a fully operational craft for pilot training.

Sources

“Air Force Studies Space Trainer”, Missile and Rockets. September 3, 1962.

Plymouth Rock: 405 Years and Counting

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The Plymouth Rock mission would have taken two Orion MPCV spacecraft, one modified for extended life support, and turn them into a single spacecraft that could undertake a six-month long mission to a small Near-Earth Asteroid. Promotional image courtesy of and ©Lockheed Martin. Click for a larger view.

What it was: A 2009 proposal by Lockheed Martin to use its Orion manned space capsule as the core of a deep space mission to the Near-Earth Asteroid 2008 EA9.

Details: Until the turn of the 21st century there were three commonly assumed steps to manned space exploration: Earth orbital, then the Moon, then the planets. While the physical gap between the first and second of these is considerable, it’s nothing compared to the step that follows. The average distance to the Moon is 384,400 kilometers; Mars never approaches the Earth to less than 54.5 million kilometers and the nature of orbital mechanics means that the path taken by any reasonable spacecraft going there must be much longer. There are several reasons why there were just eight years between the first man in space and the first Moon landing while it’s been more than four decades since with no sign of a Mars mission, but that gap is one of the biggest.

Meanwhile in recent years Lockheed Martin has been building the Orion Multi-Purpose Crew Vehicle (MPCV), an Apollo-like spacecraft built around a Crew Module and a Service Module that is currently due to make its first unmanned flight in 2014. True to its name, the Orion is supposed to be adaptable enough that it can be used for all of the missions that NASA might reasonably fly in the future, and in search of more business Lockheed has been keen to suggest ones of its own.

Plymouth Rock was one of their suggestions for the Constellation Program that began in 2004. It looked to bridge the gap between the Moon and Mars by focusing on something we’ve learned about the solar system in the last few decades. In 1980 there were fewer than twenty known asteroids that approached the Earth significantly more closely than Mars (“Near-Earth Objects” or NEOs), but as of November 24, 2012 advancing astronomical technology and fear of a reprise of the impact that killed the dinosaurs had inflated that number to 9946. Why not visit one of them somewhere out past the Moon? Not only would it increase general scientific knowledge, it would let NASA test out the technology that’s going to be needed to support astronauts on a trip to Mars without having to commit to a year or more’s travel like a full-fledged Mars mission would need.

Lockheed Martin selected 2008 EA9 as the mission’s destination, with the caveat that this selection was highly dependent on the launch date and any of a couple of dozen small asteroids might serve as a substitute. The sole criterion was that the target had to have an orbit particularly similar to Earth’s, which meant that none of them was at all notable: none even had a formal name, just a serial number, and none was larger than 75 meters in diameter. 2008 EA9 itself is approximately ten meters across.

A plain Orion wasn’t going to do the job, as it was designed for two weeks of support to the Moon and back. So a modified second Orion—the Deep Space Vehicle—would also go along for the ride. It would have been put on top of an Ares V rocket, which would have lifted it and an attached injection stage (the Earth Departure Stage, or EDS) with propellant into Low Earth Orbit. A smaller Ares I would have launched the regular Orion shortly thereafter; only two astronauts would be aboard rather than the up-to-seven that the Orion could house in Earth orbit, simply because more than that would eat through the mission’s supplies in less time than it would take for the trip there and back.

The two Orions would dock nose-to-nose in orbit and the EDS would be fired to push them on their way. Once it was out of propellant the stage would jettisoned and the Plymouth Rock spacecraft—one imagines it inevitably would have been named Mayflower—would deploy four large solar panels and begin a 92-day outbound journey. This was the other reason for only having two astronauts: each would have only 9 cubic meters to live in during the trip.

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A geocentric view of the Plymouth Rock mission’s trip to and from 2008 EA9 as it approaches Earth in late 2019. Promotional image courtesy of and ©Lockheed Martin. Click for a larger view.

Roughly 12 million kilometers later the ship would arrive at 2008 EA9 and take up station about 100 meters away. The asteroid’s mass would be so small that there would be no need to worry about its gravity, to the point that the astronauts could spacewalk over to it at will, depressurizing one of the Orions whenever they needed to enter or exit their craft.

Only something resembling the MMU “jetpacks” from the early days of the Space Shuttle would be needed to explore the asteroid as it’s likely that the tiny world’s rotation would produce centrifugal forces stronger than its gravity. Altogether this would produce a negative net force pushing anything that touched 2008 EA9 back off the surface again. This is actually a point in 2008 EA9’s favour as many asteroids are believed to be rubble piles held together by nothing more than their mutual gravitation, an arrangement that would be dangerous to explore. If 2008 EA9 spins like it’s believed to, though, it must be a solid object and so relatively stable.

After five days of exploration the astronauts would fire the engines on the modified Orion and begin their return home. This would take them another 95 days and, upon arrival at Earth, they would abandon all of their craft except for the conventional Orion’s crew capsule, which would take them down to Earth.

What happened to make it fail: As originally conceived Plymouth Rock would have been part of the Constellation program, and relied on the program’s Ares I and V rockets. With the cancellation of Constellation budget in October 2010, the mission could not go ahead as planned.

What was necessary for it to succeed: A mission to a NEO was considered one of the “big three” possible missions for Constellation (along with a return to the Moon, and a mission to Mars). While NASA tended to show it as one based on an Orion mated with an Altair lander—Constellation’s equivalent of an Apollo LM—Lockheed Martin was probably in the right in contending that two Orions were the way to go. Very few asteroids that approach Earth have noticeable gravity, so a lander would be an expensive way to do something that could be done with an astronaut on EVA instead.

As a result, Plymouth Rock likely would have gone ahead sometime around 2020 to 2025 if Constellation had continued. That said, it may be not entirely dead yet. Constellation has been replaced by the Space Launch System, which is different in detail from the earlier program but similar in broad strokes. The Orion itself is still going ahead as the manned spacecraft for SLS, and so it would be easy enough to launch a close facsimile of Plymouth Rock—though probably all in one shot aboard one of the Block IA SLS rockets being developed, as they have the throw weight to do so rather than taking two launches as per the original mission design.

Interestingly it appears that NASA may actually be interested in doing so. As of this writing a Moon landing has been taken off the list of first exploratory missions, with a lunar orbiter likely to be the first and rumours of a small station at the Earth-Moon L2 point to follow. NASA is studying a similar mission they call “Asteroid Next”, but as late as last week Lockheed Martin was still proposing a “Plymouth Rock” with a new date (2024-2025 or 2029) and a different target (either 1999 AO10 or 2000 SG344, depending on the mission date).

The latter target is an interesting choice as there’s some chance that 2000 SG344 isn’t an asteroid at all, but instead the upper stage of Apollo mission rocket abandoned in orbit and lost until its rediscovery a decade ago. If NASA does pick up on the modified Plymouth Rock then that’s something that will have to be determined before any launch in 2029.

A simple animation of a Plymouth Rock mission showing the joint Orion craft travelling to 2000 SG344 (one assuming that it’s a natural asteroid) can be seen here on YouTube.