Orbit-first isn’t just an architectural concept, it is an architectural philosophy. It recognizes the existence of established interests, political needs, divided communities, funding limitations, public interest, and scientific validity.

Consensus is emerging throughout the spaceflight community: orbiting Mars first is a critical step toward landing humans on the red planet. For more than a year, teams at the Jet Propulsion Laboratory and elsewhere within NASA have developed Mars exploration architectures that assume an orbital/Phobos mission as a first step in exploring the Martian system. And very recently Lockheed Martin unveiled its “Mars Base Camp” concept, which, as soon as 2028, would send a six-person crew to Mars orbit to rendezvous with a pre-positioned science laboratory.

The Lockheed Martin proposal builds on the findings of a workshop convened by the Planetary Society in April 2015. The resulting workshop report, “Humans Orbiting Mars: A Critical Step Toward the Red Planet” (hom.planetary.org) was released last fall. It is worth noting that the workshop and its final report were completely independent — they were funded exclusively by individual donors to the Planetary Society.

The initial impetus for the workshop was twofold: a July 2014 recommendation by the NASA Advisory Council for a “minimal architecture for humans to Mars,” and conclusions from the 2014 National Research Council report “Pathways to Exploration: Rationales and Approaches for a U.S. Program of Human Space Exploration,” which declared that no human missions to Mars were possible before the mid-2040s with existing plans and budgets.

In the period after the NASA Advisory Council recommendation, one of the authors of this essay (Hubbard) found that a team from NASA’s Jet Propulsion Laboratory had been studying a minimal architecture concept for some time, and had prepared an “existence proof” for an affordable humans to Mars program utilizing NASA’s existing hardware portfolio. It was this JPL study — with cost assessments provided by the Aerospace Corporation — that served as the focal point of the Planetary Society’s workshop.

There is an emerging consensus on NASA’s next steps in cislunar space as well. Sending humans to Mars will require deep space habitats; cislunar space is a reasonable place to test them. Thus, the vicinity of the Moon becomes a natural destination for crewed missions throughout the 2020s. This provides a clear destination for astronauts in the next decade, can enable access by commercial or international partners to the lunar surface, and directly feeds forward into the Mars goal as envisioned by orbit-first concepts. Congress has wisely (and repeatedly) provided funding and encouragement for NASA to invest in cislunar habitats.

We note that NASA is beginning to support new hardware development that will fit within the minimal architectures for Mars as conceived by both the JPL study team and Lockheed Martin. This is the NextSTEP program, which is supporting multiple companies in early development phases of deep space habitats, a critical hardware element of any long-duration human spaceflight mission. The interest from industry has been so great for deep space habitats that representatives from NASA declared that they intend to provide a contractual “on-ramp” in the near future to allow additional companies to participate.

As the transition to a new president and a new Congress approaches, it is essential to preserve and enhance the emerging consensus on how humanity is going to reach Mars. There can be no “reset” by a new occupant of the White House or through congressional mandate if humans are to reach Mars during the 2030s, if not sooner.

Orbit-first and the JPL Concept

In the 2014 “Pathways to Exploration” report, the National Research Council’s Committee on Human Spaceflight evaluated NASA’s then-existing plans for landing on Mars. The committee, employing an independent cost and schedule analysis by the Aerospace Corporation, concluded that NASA’s plans would require either an increase of billions of dollars to NASA’s budget or a schedule that stretched into at least the mid-2040s, two scenarios widely viewed as politically untenable.

By way of contrast, at the Planetary Society’s 2015 Humans Orbiting Mars workshop, JPL engineers Hoppy Price, John Baker, and Firouz Naderi provided evidence that an orbit-first approach could send humans to the Mars system substantially sooner than existing plans, assuming NASA adhered to the following core values:

  • Maximize the use of existing hardware and hardware already under development
  • Minimize dependence on new hardware
  • Build only what is absolutely needed, and design each mission to feed into the next
  • Use cislunar space and the lunar surface to validate hardware and operations
  • Expect minimal budgetary growth

As envisioned by the JPL study team, astronauts would use the Space Launch System/Orion configuration to travel to a cislunar habitat throughout the 2020s to demonstrate deep space operations and validate critical technologies. In the early 2030s, NASA would pre-position cargo at Mars via solar electric propulsion tugs. A human mission to Mars orbit and Phobos would launch in 2033 and remain there for a year.

This parallels the practice of building on previous mission experiences established decades ago with the Apollo 8, 10, and 11 missions. Orbiting first provides focus on testing the systems required to travel to and from the vicinity of Mars while avoiding the additional technical challenge and cost of attempting Mars entry, descent, landing, and ascent.

But once NASA and its partners validate the technologies and systems required to reach Mars orbit, the next mission in the JPL architecture would attempt a short-stay surface mission on Mars in 2039. In the interim, a 2036 end-to-end test of this landing system would occur by landing a crew on the surface of the Moon. Long-stay missions would begin in the early 2040s, kicking off a regular cadence and crew rotation at a science base on Mars.

The Aerospace Corporation, which provided the cost analysis for the National Research Council’s “Pathways to Exploration” report used the same methods, assumptions, and models to evaluate the JPL study team’s architecture. Aerospace found that this orbit-first approach could fit within the existing human spaceflight budget if: a.) the budget increased with inflation and, b.) NASA divests itself from funding operation of the International Space Station by 2024 or, at the latest, 2028.

In the year since the Planetary Society’s Humans Orbiting Mars workshop, JPL has further refined its concept and published details in a peer-reviewed journal (New Space, Vol. 3, No.2 , 2015, pp.73 – 81).

Orbit-first and Mars Base Camp

On May 19, Lockheed Martin released its own orbitfirst humans-to-Mars architecture: the Mars Base Camp. The team at Lockheed Martin, led by former astronaut Tony Antonelli, embraced the same core values behind JPL’s orbit-first approach, including the maximal use of existing hardware, feed-forward mission design, the use of cislunar space as what NASA calls the technology “proving ground,” and the acceptance of constrained budgets.

The Lockheed plan also leverages the capabilities of the existing Orion and Space Launch System programs. The plan’s deep space habitat for cislunar space would feed forward into the development of a Mars habitat. Mars Base Camp also employs a large solar electric propulsion system, currently under development as part of NASA’s Asteroid Redirect Mission (ARM), to pre-position the science laboratory in Mars orbit. Whatever the fate of ARM — the House Appropriations Committee voted May 24 to cut off funding for the program — developing the solar electric propulsion system is essential to both the JPL and Lockheed Martin approaches. The crew arriving from Earth would rendezvous with this laboratory and carry out sorties to the Martian moons using two Orion spacecraft, included as part of the “base camp,” while also operating rovers on the Martian surface. The lack of any significant time delay in communication between Mars orbit and the planet’s surface would make such robotic exploration much more efficient, a benefit also discussed in detail in the Planetary Society’s “Humans Orbiting Mars” report.

Most intriguingly, the Lockheed Martin proposal accelerates the timeline for an initial journey to Mars orbit to 2028 — a full five years earlier than the JPL concept. The plan also lays out a regular cadence of missions to cislunar space throughout the 2020s to engage the public and focus the development and testing of the deep space habitat and operations.

It is encouraging to see one of the world’s largest aerospace companies put out a comprehensive, aggressive, and executable plan for the human exploration of Mars that is consistent with the orbit-first approach. We are pleased to see that the independent effort by a membership supported nonprofit organization like the Planetary Society has helped inform this plan.

An Emerging Consensus and Coalition

One of the key findings from the Planetary Society’s workshop was that the orbit-first approach could help define a new consensus that could form the coalition needed to achieve the human exploration of Mars. We believe that this consensus is emerging.

A year after the Humans Orbiting Mars workshop, there are now multiple orbit-first solutions to planning for Martian exploration. If one accepts the political and budgetary constraints that govern human spaceflight ambitions to Mars, orbit-first appears to be the convergent solution. A growing number of experts have examined the problem and embraced the idea of orbiting Mars first before landing. Orbiting first squares the circle of how to use the heavy lift and deep space systems NASA is currently developing, provides a clear set of priorities for technology development, and provides a rationale for the spaceflight program in cislunar space throughout the 2020s while maintaining a focus on Mars.

Another potential ally in this growing coalition is the science community, which is often underrepresented in discussing the future of human exploration. The Planetary Society’s report recommended that this community be engaged from a very early point to help define and enable the scientific exploration goals. NASA has begun work to this effect in its “Exploration Zone/Landing Site” workshops, while Lockheed Martin wisely made science the primary effort of its Mars Base Camp. The Planetary Society’s workshop demonstrated that the scientific community places great value on sample return from Mars and Phobos, as well as the teleoperation science assets on the surface. This is a coalition-building opportunity that should not be missed.

Of course, commercial entities and international partners will be critical coalition partners moving forward. As noted above, the minimal architecture for orbit first would provide an enabling presence in cislunar space for organizations who express interest in landing on the Moon. Shared technological interests, such as SpaceX’s intention to test supersonic retropropulsion for Mars entry, descent, and landing, also demonstrate significant promise for the orbit first direction. An effort as large as the JPL concept study or Lockheed’s Mars Base One will require the participation of many partners.

Orbit-first isn’t just an architectural concept, it is an architectural philosophy. It recognizes the existence of established interests, political needs, divided communities, funding limitations, public interest, and scientific validity. It provides a flexible but clear way for NASA to lead the world in deep space exploration while enabling new exploration by its commercial and international partners. Orbit-first helps provides the immediate programmatic guidance for technology and hardware development. There is great promise in this concept, and the emerging consensus behind this approach helps to demonstrate this. The Planetary Society is proud to have played a role in highlighting the benefits of humans orbiting Mars, and is encouraged by the response to date to its pathbreaking effort.

Scott Hubbard and John Logsdon are members of the Board of Directors of the Planetary Society and were co-chairs of the Society’s 2015 Humans Orbiting Mars workshop. Casey Dreier is the director of space policy at the Planetary Society.

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