NEEMO 16 begins – Real NEA mission outline continues to be worked

by Chris Bergin

The international crew of the NEEMO 16 (NASA Extreme Environment Mission Operations) mission have begun their mission at the Aquarius underwater habitat in Key Largo, Florida. The 10 day mission will simulate Near Earth Asteroid (NEA) exploration procedures, although a real mission remains a notional and undefined target.


NASA astronaut and former space shuttle crew member Dottie M. Metcalf-Lindenburger is leading the mission, assisted by former British Army Air Corps Major Timothy Peake – who is representing ESA. Kimiya Yui of the Japan Aerospace Exploration Agency and Cornell University professor Steven Squyres – who was also a NEEMO 15 crew member – complete the crew.

Living and working 63 feet below the Atlantic Ocean’s surface on the National Oceanic and Atmospheric Administration’s Aquarius Reef Base undersea research habitat, the NEEMO 16 expedition will focus on restraint and translation techniques, and optimum crew size.

Adding to the realism of a deep space mission at an asteroid, NASA’s Mission Operations Directorate (MOD) are involved once again, treating actual EVAs (or Waterwalks) during NEEMO 16 as if they are in deep space by utilizing communication delays and protocols. The MOD team is based in a mobile Mission Control Center (MCC).

Last year’s NEEMO 15 was the first real full scale operation, continuing the trend of testing equipment and operations required for exploration of Near-Earth Asteroids (NEAs).

The missions treat the underwater environment like a giant Neutral Buoyancy Laboratory (NBL), allowing for specialist divers to simulate working on a NEA, communicating – with time delays – with mission control and practising the use of tools to work on an asteroid.

A key objective of the NEEMO missions is the evaluation of different anchoring methods and how to connect the multiple anchors to form pathways.

The aquanauts and engineers evaluate different strategies for deploying instruments and moving along a surface without gravity, mirroring conceptual graphics of an astronaut working up close and personal with a NEA.

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Adding to the realism, the mission includes the use of DeepWorker submersibles, acting as an underwater stand-in for the Multi Mission Space Exploration Vehicle (MMSEV), which is currently the leading concept to be the main NEA exploration vehicle at the site at the asteroid, utilizing its robotic arms and crew airlock.

Aquarius acts as the Deep Space Hab (DSH) for these missions, a large element of hardware that would arrive at the NEA after being launched from Earth on the Space Launch System (SLS) – likely the 105mt Block 1A Heavy Lift Launch Vehicle (HLV) or the new variant of the SLS that will be reported in an upcoming article.


Technically, a lot of work has been completed on the baseline for a mission to a NEA, not least the options for how the mission would be conducted once at the asteroid. However, a preferred plan – and indeed a destination – remains completely undefined, with the notional target for such a mission placing it at least 13 years into the future.

There is no need to rush towards a full outline, not least because it is so many years away, although NASA recently explained the complex nature of at least selecting which asteroid to visit and the challenges of sending a crew safely there and back.

“Because there are thousands of known NEAs, and likely many more to be discovered, one of the first challenges of a NEA mission is choosing the ideal destination,” noted a public exploration overview presentation. “Distance is another challenge. Although some NEAs pass close to Earth, even within the Moon’s orbit, larger and more interesting NEA destinations may be tens of millions of miles away.

“To reach these NEAs, astronauts would have to travel about six months for a round trip, which is a long time to go without a resupply of water, food, or air longer than has ever been attempted in space.”

To date, the only notional targets were revealed in the “Flexible Approach” presentation (available on L2 -LINK), created after the Augustine Commission’s review into NASA’s Human Space Flight activities.

A mission to Near Earth Object 1999AO10, requiring a mission launch date of January 2, 2026, is the first case example examined by the NASA authored study.

The NEO 1999AO10 deep space mission would last 155 days, around half of the mission length for the alternative candidate mentioned in the Flexible Path approach – 304 days – for a mission to NEO 2001 GP2.

How to get both the crew and the considerable amount of hardware to a NEA destination is also still under evaluation, with multi-launch SLS campaigns the baseline approach, and the use of an Exploration Platform or Gateway – as the centrepiece of several exploration pathways – the alternative.

A several month internal study – a high level effort within the ongoing NASA exploration roadmap evaluation drive and specific to the Gateway – is coming to a conclusion this month.

This relates to a Gateway that would be built at the International Space Station (ISS) and then sent to Earth Moon Lagrange point (EML2) via Solar Electric Propulsion (SEP). This Gateway would provide a staging post for missions to the Lunar Surface, NEAs, Mars and potentially other destinations.

For a NEA specific mission, Boeing outlined a conceptual approach involving the EML2 Gateway at last year’s Global Exploration Workshop. Under this Boeing plan, Solar Electric Propulsion would be used by NASA for NEA missions – a technology also cited by Aerojet.

This new propulsion system would be gradually developed over the next 10 years, although a demonstration flight would be capable of readiness by 2014.

A NASA docking system, Spacecraft boom, triple panel SEP module, Solar Array mast, and Alpha-joint (similar to the ISS’ Beta joint) would be developed between 2016 and 2020 – all leading to the creation of a 320 kW SEP operational spacecraft for NEA missions by 2022.

Under the Boeing notional plan, a 2024 NEA mission to NEA2008EV5 would depart not from Earth but from the ISS-EP at the Earth-Moon L2 (EML2) point.

Using the new SEP technology, transit from the EML2 point to the NEA of interest would take approximately 100 days with SLS’ third stage used to “kick start” the stage and shorten the trip. SLS would be involved with the Gateway plan.

Investigations at the NEA would last for approximately 30 days before a ~235-day trip back to Earth for a total mission duration of roughly one year.

This alternative plan is internally considered as the most exciting option, with a full outline of the Gateway options and progress into its development roadmap to be outlined in a future article.

(Images: L2 Content, NASA, NEEMO and Boeing)

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