On The Path To a Modular Exploration Architecture

Cygnus Approach Orion Image Credit: OSC

One of the most common arguments put forward in support of NASA’s current program of exploration using the Space Launch System and Orion spacecraft is that alternative modular missions launched by smaller boosters are inherently too complicated. The ISS, which required dozens of Shuttle and Russian launches to complete, is cited as the the poster child for the costs and headaches of such an approach.  Ironically enough, NASA is well on the way towards demonstrating why a modular model is necessary after all.

In September, Orbital Sciences Corporation gave a Future In Space Operations (FISO) presentation entitled “Orbital Beyond Low-Earth Orbit Logistics.” The presentation, which focused on possible new applications for the Cygnus resupply vessel can be found on the University of Texas server here.

The bottom line is that the Cygnus resupply vessel, which is essentially an ISS Multi-Purpose Logistics Module built by Thales-Alenia mounted to a service module adapted from heritage Orbital components, is only the current iteration of a long line of pressurized logistics modules whose future applications are almost limitless. While the current Cygnus is relatively small, offering 18.9 cubic meters of pressurized space and 2,000 kg. cargo capacity, it is a capability limited by the Antares launch vehicle. According to OSC, an enhanced version offering 26.1 cubic meters and 2,700 kg capacity will be used on later ISS flights.

As part of the FISO presentation however, OSC pointed out that there is relatively little work required to produce a considerably more robust 7.5 meter long version offering 33.5 cubic meters pressurized space and 3,400 kg. cargo capacity. In that version, the “Super 4-Segment Configuration” or “Exploration Augmentation Module (EAM)”  could support a four person crew for up to 60 days, attached to an Orion spacecraft.

To put it bluntly, a Cygnus EAM could offer many of the features that Orion does not, such as research and habitat space or hygiene facilities, allowing extended stays in Cis-Lunar space. It could even offer an airlock. Other variations could offer internal bulkheads, side or even dual hatches, with one at each end. It is in other words, potentially the first piece of an emerging exploration architecture which is actually affordable.

NASA is clearly interested, as indicated by a presentation by Chris Moore, deputy director of the Advanced Exploration Systems Division at NASA headquarters at the 65th International Astronautical Congress earlier this month. In the presentation,. Moore discussed the potential of adding an Exploration Augmentation Module similar to Cygnus to NASA’s planned Asteroid Redirect Mission (ARM) in order to extend the mission beyond what is anticipated to be a 5 day stay using Orion alone. Quoted in Space News, Moore said “We’re doing a study now of different module types and different times it could be launched…It may be used on the first mission, if it could be ready in time.”

Based on the FISO presentation, Orbital would very much like to provide just such a capability to NASA. It is worth pointing out that at no point in the presentation does OSC mention the perfectly obvious, that the same system could be equally well adopted to other, more affordable spacecraft such as the SpaceX Dragon or Boeing CST-100.

For a company which tries very hard to never mention SpaceX by name, the omission is hardly surprising. Neither is the fact that as it seeks to integrate SLS Solid Rocket Booster manufacturer Alliant Techsystems (ATK) into its “merger of equals,” OSC which once described itself as the original NewSpace company, will inevitably, and perhaps even happily be drawn into the “old space” network.  And that may be okay.

Viewed from a slightly skewed, but perversely optimistic angle, the integration of a Cygnus EAM into NASA’s SLS/Orion matrix is a good thing precisely because it proves the point adherents to the SLS architecture seek to refute, that until something like Elon Musk’s rapidly reusable, and thus actually affordable BFR comes along,  the future of human space exploration is going to be modular.

This was a point made oddly enough by a critique which was not  leveled at the Mars One plan by a group of MIT graduate students last week. While the study took for granted the modular transportation architecture which Mars One puts forward,  and focused instead on the many hazards of a one way trip once arriving on the surface, is was an assumption made possible precisely because it is so non-controversial. Mars One envisions a capsule/lander, and habitat module suspiciously similar to an Orbital EAM, connected to two “propulsion modules” for the journey to Mars.

NASA, even at this juncture, is focusing on much the same thing (absent the propulsion modules) in order to make the $16 billion dollar Orion spacecraft of any practical use whatsoever. Again, from the article:

“One end of the module would attach to the robotic spacecraft that redirected the captured asteroid into lunar orbit, with Orion docking at the opposite end. The module could also include an additional docking port to allow logistics spacecraft to dock while Orion is there, and an airlock so that astronauts could perform spacewalks without depressurizing the Orion, as currently planned.”

As proposed, the ARM could consist of a minimum of four elements; a small asteroid or large rock, a robotic retrieval spacecraft, a Cygnus like EAM, and finally an Orion, with three different “docking” operations; one in deeper space, and two in Cis-Lunar space. If “logistics” spacecraft are employed, the event count rises further.

Whatever one makes of the ARM concept in general, and opinions certainly vary, the early integration of beyond LEO logistics, as well as the tacit endorsement of modular architectures could speed the transition to a more sustainable exploration model, if and when the day comes, as many predict, that SLS/Orion is dismissed as too expensive.


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