**[Lunar Lander Concepts Requirements Description]{.underline}**

 

The National Aeronautics and Space Administration (NASA) Exploration
Systems Mission Directorate (ESMD) Constellation Program Office (CxPO)
is assessing concepts for lunar landers that will deliver crew and cargo
to the surface of the moon late in the next decade. An in-house
conceptual design effort involving the NASA Field Centers is currently
underway, and this RFI invites respondents to submit concepts that are
derived from the same requirements, ground rules and product lists used
by the NASA Field Centers to initialize their studies. These
requirements, ground rules and product lists are given in the 9 numbered
sections that follow.

[1. Concept Study Introduction]{.underline}

Since the announcement of the Vision for Space Exploration, NASA has
both contracted industry studies and conducted internal studies
investigating concepts for lunar mission architectures and the flight
elements required for these architectures. Most recently, NASA
contracted with 11 industry partners in the development of Concept
Exploration and Refinement studies (CE&R), and then used the CE&R
results as inputs to its internal Exploration Systems Architecture Study
(ESAS), which became the basis of its current exploration planning. NASA
has since refined its exploration requirements, begun procurement of the
initial components of its exploration architecture, and begun refined
conceptual studies of the follow-on elements of the architecture.

This Request for Information describes a small set of requirements, a
list of "desirements", and a short list of bounded trade studies that
internal NASA teams are using to develop a broad catalog of lunar lander
concepts. NASA is releasing this initialization package so that all
interested parties may independently participate in the lunar lander
conceptual study.

[2. Concept Study Background]{.underline}

The Lunar Surface Access Module (LSAM) derived during NASA's ESAS study
was a preliminary concept with the ability to support a wide array of
potential surface missions ranging from short science missions
distributed across the lunar globe to supporting the build-up of a large
lunar outpost at the south-pole. The ESAS LSAM was an excellent
synthesis of options, given the 60 days of work that went into its
design. It provided a basic understanding of the systems, operations,
costs and risks of this vehicle, while acknowledging a significant
portfolio of work to be completed in the post-ESAS timeframe. It was
not, nor was it intended to be, the final answer. The ESAS study may be
accessed at
<http://www.nasa.gov/mission_pages/exploration/news/ESAS_report.html> .

Since the conclusion of the ESAS study, refinements to the exploration
architecture have taken place. While most changes have targeted the Crew
Exploration Vehicle (CEV) and Crew Launch Vehicle (CLV), the one that
most directly affects the lunar lander design directly is the deferment
of Lox/Methane propulsion selection for the CEV (and by association, the
LSAM ascent stage) in favor of storables.

With these refinements in place, and a more defined set of exploration
requirements in place, it is now prudent to explore diverse sets of
lunar lander design configurations that may yield more innovative
solutions to supporting lunar surface missions.

[3. Concept Study Objectives]{.underline}

The objective of this study is to define innovative lunar lander
approaches that meet the fixed requirement set and fall within the
bounding cases for trade studies. Each conceptual design team should use
these common requirements and trade space boundaries to perform analysis
and design of innovative lunar lander designs. The internal NASA study
is taking place in two stages, with the initial phase of the study
exploring multiple design concepts, including the relationship of the
lander to potential surface systems, and a second phase down-selecting
from the initial phase concepts to refine performance and design, and
develop cost estimates, development schedules, and risk analyses. In
this second phase, teams are also deriving technology development needs
and requirements for robotic precursors, including estimates of how each
investment will impact the cost or risk of the human mission.

[4. Concept Study Approach]{.underline}

NASA is releasing this initialization package to all parties interested
in performing lunar lander conceptual studies in parallel with the
internal NASA teams.

The internal NASA teams are investigating the widest possible tradespace
for innovative solutions, using the ESAS LSAM design as a point of
departure. Expected products include refine the design of the lunar
lander, including descent stage propulsion system packaging, descent
stage payload packaging options, ascent stage design including crew
cabin layout, piloting sightline/visibility studies, airlock design, and
split volume options. Additionally, ascent stage propulsion system
packaging, Reaction Control System (RCS) layout, lander structure,
including landing gear, and launch vehicle packaging require additional
work.

The ESAS study touched only briefly on alternate deployment concepts for
lunar outposts and concluded by supporting an "incremental build"
strategy that integrates the lander and surface system deployment and
functionality. With the Earth Orbit Rendezvous -- Lunar Orbit Rendezvous
(EOR-LOR) architecture now fixed, this study should more fully explore
options for deployment of a lunar outpost in pieces that can be packaged
within this excess landed mass. This should be integrated with any
lander reconfiguration study that contemplates leaving behind part of
the habitable lander volume, airlock, etc.

[5. Concept Study Products]{.underline}

Internal NASA teams have been asked to provide the following products,
in two phases:

Phase 1:

-   Innovative lander design concepts

-   Graphics showing size, general arrangement, shroud packaging,
    payload accommodations, crew access to surface, crew piloting
    position

-   Vehicle performance characteristics -- for Phase 1, mass estimates
    (by subsystem)

-   Identification of driving requirements

-   Results of sensitivity studies

-   Concepts for integration of the lander and surface systems, e.g.,
    deployment of surface outpost habitation

Phase 2:

-   Refined design concepts

-   Updated vehicle performance characteristics

-   Updated trade/sensitivity studies

-   Cost estimates

-   Development schedules

-   Identification of top risks

-   Identification of technology drivers

-   Identification of precursor mission flight experiments

    [6. Fixed Study Requirements]{.underline}

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-   Dual rendezvous mission mode (EOR+LOR)

-   Cargo Launch Vehicle (CaLV) Trans-Lunar Injection (TLI) capability
    from 296 km (160 nmi) circ (assuming 20 mt CEV at TLI):

  -----------------------------------------------------------------------
  Shroud Diameter (m)        Net Lander Payload to TLI (mt)\
  8.4                                         45.0\
  10.0                                       40.7\
  12.0                                       38.0

  -----------------------------------------------------------------------

-   Cargo mission (single launch) TLI mass: 53.6 mt

-   Low-Impact Docking System (LIDS) docking system

-   LSAM performs attitude control and Trajectory Correction
    Maneuvers)TCMs during trans-lunar coast

-   LSAM performs lunar orbit insertion, deorbit, powered descent,
    hazard avoidance, terminal landing, ascent, and rendezvous.

-   CEV remains in 100 km (54 nmi) circular Low Lunar Orbit (LLO)

-   4 crew members for lunar missions

-   500 kg minimum science/technology payload down to lunar surface

-   100 kg minimum payload return from lunar surface to Earth

-   Surface airlock

  ------------------------------------------------------- ---------------
  **Sortie Mission Delta V Allotment**                    

  **Maneuver**                                            **Delta V
                                                          (m/s)**

  TCM                                                     10

  Lunar Orbit Insertion (LOI)                             1100

  Lunar Descent                                           1911

  Lunar Ascent                                            1850

  Rendezvous with CEV in LLO                              37

  Ascent Stage Disposal                                   23
  ------------------------------------------------------- ---------------

*Sortie Delta-V notes:*

-   Descent stage main propulsion = 10 m/s MCC + 1100 m/s LOI + 1900 m/s
    descent = 3010 m/s

-   Descent RCS = 11 m/sec

-   Ascent stage main propulsion = 1850 m/s ascent + 16 m/s rndz + 23
    m/s disposal = 1889 m/s

-   Ascent RCS = 11m/sec +10m/sec rndz = 21 m/s

  ------------------------------------------------------- ---------------
  **Outpost Mission Delta V Allotment**                   

  **Maneuver**                                            **Delta V
                                                          (m/s)**

  TCM                                                     10

  LOI                                                     845

  Lunar Descent                                           1911

  Lunar Ascent (crewed mission only)                      1868

  Rendezvous with CEV in LLO (crewed mission only)        37

  Ascent Stage Disposal (Crewed mission only)             23
  ------------------------------------------------------- ---------------

*Outpost Delta-V notes:*

-   Descent Stage main propulsion= 10m/s MCC + 845 m/s LOI + 1900 m/s
    descent = 2755 m/s

-   Descent RCS = 11 m/s

-   Ascent stage main propulsion = 1868 m/s ascent + 16 m/s rndz + 23
    m/s disposal = 1907 m/s

-   Ascent RCS = 11 m/sec +10 m/sec rndz = 21 m/s

    [7. "Desirements"]{.underline}

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-   Common systems with CEV

-   2200 kg of additional landed cargo payload on crew flights

-   Leaving hardware behind that can be used for incremental Outpost
    buildup

-   Capable of reuse or evolving to reusability

-   "Green" propellants

-   Capable of utilizing locally produced propellants using In-Situ
    Resource Utilization (ISRU)

-   Unpressurized cargo stowage volume

-   Ease of surface access for crew and cargo

-   Extensibility to a dedicated cargo lander (refer to ESAS Report,
    Section 4 for cargo mass data and descriptions)

    [8. Bounded Trade Studies]{.underline}

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-   CaLV shroud diameter 7.5 m (27.6 feet) (7.5m) -- 12.0 m (39.4 feet)

-   Dynamic envelope:

    -   12 meter shroud (39.37 feet); working diameter = 10.3 meters
        (33.8 feet)

    -   10 meter shroud (32.81 feet); working diameter = 8.77 meters
        (28.77 ft)

    -   8.4 foot shroud (27.6 feet); working diameter = 7.5 meters (24.6
        ft)

-   Surface duration -- 4 days (minimum) to 180 days

    [9. Open Trade Studies (as a minimum)]{.underline}

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-   Crew cabin volume

-   Crew cabin configuration

-   Number of stages

-   General vehicle configuration

-   Propellant/engine selection

-   Terminal landing system