NASA Exploration Roadmap: A return to the Moon’s surface documented

by Chris Bergin

The latest documentation relating to the efforts to create an Exploration Roadmap for NASA’s future has provided the strongest indication to date that the Agency wants to return US astronauts to the surface of the Moon. Listed as a Lunar Surface Sortie (LSS) mission, the Exploration Systems Development Division (ESD) revealed their plans via their latest Concept Of Operations (Con Ops) document.

The SLS/Orion Roadmap:

Publicly, only vague timelines and destinations continues to be the official line provided by NASA. However, behind the scenes, teams are closing in on a defined roadmap, one which is far more exciting than NASA administrator Charlie Bolden cared to portray to lawmakers during a recent hearing with Senators.

Right now, the Agency has only provided the “party line” of two test flights around the moon, a visit to a Near Earth Asteroid (NEA) sometime in the mid 2020s and the eventual crewed missions to Mars in the mid 2030s.

As noted by some people working within the exploration effort, there is a level of frustration that the Agency’s own top boss appears more politically fixated in salvaging the remains of President Obama’s defunct FY2011 budget proposal, as opposed to promoting what they claim is an exciting exploration roadmap development process.

General Bolden, however, recently claimed no one is “more passionate” about SLS and Orion than him, despite what appeared to be efforts to continually roadblock the HLV’s progress under his command.

This continuing effort in creating an expansive roadmap is backed up by documentation, which outlines a large amount of work on an array of missions to push the United States back into deep space.

Two vehicles are at the center of this return to Beyond Earth Exploration (BEO), with the Space Launch System (SLS) providing the muscle to loft the heavy elements of hardware into orbit, and the Orion (MPCV) – which will be the Agency’s crew vehicle of choice.

Technically, the duo have a standby role of providing crew rotation on the International Space Station (ISS), a requirement stated in the 2010 Authorization Act, as much as this role is highly unlikely, as it would take a serious problem with the Commercial Crew schedule to result in the overpowered SLS launching a BEO designed Orion to the orbital outpost.

Regardless, this requirement is listed in the March ESD Con Ops Document – acquired by L2 (L2 Link to Presentation) – as a Design Reference Mission (DRM), listed as ISS Back-up Crew Delivery, which “delivers crew members and cargo to ISS if other vehicles are unable to perform that function. Mission length 216 mission days. 6 crewed days. Up to 210 days at the ISS.”

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SLS/Orion To The Moon:

SLS’ opening role – under a nominal scenario for the Heavy Lift Launch Vehicle (HLV) – is now well known, with a mid-December, 2017 launch of a Block 1 (70mt) SLS with an Interim Cryogenic Propulsion Stage (ICPS), launching an unmanned Orion on a 7-10 day mission to the Moon, with an aim to qualify the Heavy Lift Launch Vehicle (HLV) and Beyond Earth Orbit (BEO) Orion to carry humans into deep space.

Known as Exploration Mission 1 (EM-1), Orion will be sent around the far side of the Moon, prior to a splashdown in the Pacific Ocean.

“Uncrewed Lunar Flyby: Uncrewed mission Beyond Earth Orbit (BEO) to test critical mission events and demonstrate performance in relevant environments. Expected drivers include: SLS and ICPS performance, MPCV environments, MPCV re-entry speed, and BEO operations,” noted the Con Ops presentation.

This DRM lists the Total Payload Gross Liftoff Mass at 62.2 tons, with SLS’ Payload Insertion Mass at 50.4 tons. The document also notes that the mission duration may be tweaked, listing a slightly different timeline of 6-8 mission days, with around one day at the destination.

The next scheduled mission on the DRMs relates to EM-2, which is listed as the Crewed Lunar Orbit. Publicly, the Agency has listed this mission as a 2021 launch. However, as previously reported and acknowledged by General Bolden recently, the effort to push this date to 2019 is being evaluated.

“Crewed mission to enter lunar orbit, test critical mission events, and perform operations in relevant environments,” added the Con Ops. “Expected drivers include: SLS and ICPS performance, crew support for BEO mission duration, MPCV delta V, MPCV re-entry speed.”

With a crew of four onboard the Orion for the trip to the Moon, the DRM lists slightly different numbers than EM-1, with a Total Payload Gross Liftoff Mass at 68.8 tons, with SLS’ Payload Insertion Mass at 57.0 tons. This mission would have a length of 10-14 days, with four days at the destination – pointing to numerous Lunar orbits for Orion and its crew.

These two missions are listed under the Tactical Timeframe DRMs, whereas a third Lunar orbit mission is listed under the Strategic Timeframe DRMs. The major difference is the launch vehicle, with the 105mt capable Block 1A SLS being used, with a Block I CPS.

“Low Lunar Orbit (LLO): Crewed mission to LLO. Expected drivers include: SLS and CPS performance, MPCV re-entry speed, and LLO environment for MPCV,” added the document.

Total Payload Gross Liftoff Mass is shown as a hefty 103 tons, with SLS’ Payload Insertion Mass at 97.5 tons for a 12 day mission, three of which would be in Lunar orbit.

Notably, the difference between the ICPS and the CPS is a major factor, with the ICPS likely to be very similar to the Delta Cryogenic Second Stage (DCSS) – which will hook up with Orion in 2014 during the Exploration Flight Test (EFT-1) mission.

The CPS – which has been under evaluation for around two years and is now finally under the direction and funding of the SLS program – is entering into its RAC (Requirements Analysis Cycle), which should be completed in May.

According to L2’s SLS Development update section (L2 Link) CPS’ that are being studied in this RAC will be early versions that could store propellants for as much as eight days for use in lunar orbit or somewhere else in cislunar space. The first flight would be in the early 2020s.

Additionally, multiple versions are being studied. using as few as two – or as many as four – RL-10 engines for propulsion.

Lunar Missions To The Surface:

Technically, a return to the surface of the Moon was cancelled when the Constellation Program (CxP) ended. However, a growing movement within the exploration community at NASA resulted in documented references into the potential of new footprints being placed on our nearest neighbor.

Once again, this effort hasn’t been publicly promoted by NASA, nor was it referenced to lawmakers during the recent hearing involving General Bolden.

Regardless, once again, documentation placed the potential for such missions firmly into the spotlight, with the ESD Con Ops listing it alongside the main NEA missions under the Architectural Timeframe DRMs.

“Lunar Surface Sortie (LSS):  Lands four crew members on the surface of the Moon in the equatorial or Polar Regions and returns them to Earth,” noted the presentation.

“Expected drivers include: MPCV operations in LLO environment, MPCV uncrewed ops phase, MPCV delta V requirements, RPOD (Rendezvous, Proximity Operations and Docking), MPCV number of habitable days.”

A lot will hinge on the ability to include a Lunar Lander into the Exploration Roadmap, as listed in the presentation’s outline on the hardware elements relating to the forward plan.

“Lunar Lander: Transports crew to/from the Lunar surface and supports crew for short duration surface stays. Sortie two-module configuration has Descent Module (DM) and Ascent Module (AM). AM includes Suit Ports and a side hatch opening to the lander deck. Crew equipment, supplies, and consumables stowed in the AM.

“A three-module vehicle configuration for extended stays consists of the DM, the AM, and a Suit Lock/ Suit Port (SL) module.”

It is unknown if this vehicle would result in the resurrection of the Altair lander – as depicted for use with the Constellation Program – although a foundation of work on variants of this lander would be available to the engineering teams.

As listed in the Con Ops, this mission – based on just SLS related hardware – would involve two Block 1A SLS vehicles, launching 121 days apart. The first SLS would launch the Lunar Lander, with a Block 1 CPS, followed by the second SLS launching a crew of four on Orion for a 19 day mission, with seven days on the Moon.

No dates are provided by the Con Ops, although based on the availability of the SLS Block 1A, such a mission would be viable by the first half of the 2020s.

Also providing a boost for the roadmap that includes Lunar destinations – as a stepping stone towards NEA and eventual Mars missions – is the large amount of work taking place on evaluating an “Exploration Gateway“.

ISS and Exploration teams are currently involved in what is being described as “L2 WayPoint Activities“, with cross-center sources claiming a groundswell of support for marrying SLS and Orion to this drive after the EM-2 mission. See L2’s Exploration Roadmap Update section for additional information (L2 Link).

As such, the roadmap appears to be closing in on the two SLS missions to qualify the launch vehicle and Orion, hopefully by 2019, prior to the drive towards constructing and deploying – via Solar Electric Power (SEP) – the Exploration Platform to EML-2.

With either SLS only, or Exploration Platform involvement, sortie missions to the Lunar surface would then take place, followed by NEA missions. The NEA mission DRMs take up a large amount of the ESD Con Ops overview and will be covered in an upcoming article

This would all play a role towards the main goal of crewed missions to Mars. While the ESD Con Ops failed to list any Mars related DRMs – classing them as To Be Determined (TBD) – documentation on L2’s Exploration Roadmap section recently acquired notes that show this effort is under evaluation.

Phobos/Deimos Con Ops Team (is) now up and running to define potential Human Mission activities at the Mars moons,” claimed the documentation – which mirrors all recent Mars mission documentation, pointing to a mission to one of Mars’ moons, before landing on Mars itself.

However, it remains likely that General Bolden’s claim such Mars missions won’t take place until the mid 2030s is accurate, and – as with all the DRMs – is at the mercy of political support and NASA funding levels.

Images: Via L2 content, NASA and Boeing.)

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