New SLS mission options explored via new Large Upper Stage

by Chris Gebhardt

As NASA’s Space Launch System (SLS) rocket continues toward its initial debut in 2017, a Boeing proposal for a new Large Upper Stage for the rocket would see SLS gain the ability to perform more complex, long-range missions in a more cost-effective manner.

New missions for SLS:

As previously reported by, Boeing has brought forward a proposal to use the current machining technology at the Michoud Assembly Facility, that will be used to construct the Space Launch System’s (SLS’s) core stage, to construct a new, Large Upper Stage (LUS) for SLS.

Z8This proposed LUS would provide SLS with considerable more lifting power for payloads to translunar, solar, Martian, and Uranian targets.

According to the Boeing presentation, available for download on L2, “SLS will play a critical part in enabling the next steps in human space exploration beyond Earth orbit.”

While this has always been a goal of the SLS, as defined by NASA, Boeing’s proposed new LUS would provide greater mission range and support capabilities to already-identified exploration targets and increase SLS’s viability as a competitor in the launch market for translunar, solar, and outer solar system missions.

Building an outpost in Translunar Space:

Building off of NASA’s recently announced initiative to use some of the opening missions of SLS to capture an asteroid and bring it Earth-local space, Boeing identifies the construction of a translunar outpost as critical to the success of this endeavor.

As stated by Boeing, “Building a translunar outpost is an important first step in retrieving an asteroid, returning to the moon or venturing to Mars.”

Z38Based on NASA’s intention to use SLS in a “phased development plan” that will increase SLS’s payload lift capability to increasingly larger payloads, Boeing notes that “The SLS will be ideally suited to deliver a variety of payloads to translunar space.

“A SLS/LUS could launch multiple translunar elements simultaneously, reducing the number of overall launches and decreasing the time required to assemble a translunar outpost.”

Reducing the number of launches needed to loft a translunar outpost by the simple addition of the new LUS (machined from already-existing hardware) would add to the promised cost-effectiveness of the SLS rocket – something that has been seen in the initial design cycles of the rocket with the use of numerous Shuttle-Derived Technology components.

Furthermore, a translunar outpost could be used as “An Exploration Platform … [that] would improve the science and technical return of the early missions while also increasing Orion capability through resource provision and providing an abort location and safe haven for vehicle contingencies,” states the Boeing presentation.

This would allow for increased mission duration and safety as well as expanded mission options including sorties to the moon and use of the outpost as an exploration platform from which to commence travel to NEOs (Near Earth Objects) and NEAs (Near Earth Asteroids).

While the proposed configuration of this Exploration Platform in translunar space is just that, a proposal, Boeing has identified several preliminary characteristics of the platform.

Z10These include input and construction assistance from the international space community, notably the Russian Federal Space Agency’s prime contract company RSC Energia – with whom Boeing has already performed an initial proposal study.

According to Boeing, “Russian systems are well developed and ideal for these new uses, such as adapting current Russian Science Power Module (SPM) and node designs for translunar use.”

However, RSC Energia, upon studying the initial proposal, identified a hybrid module as the best option for an Exploration Platform in translunar space.

According to the Boeing report, this hybrid module would “shorten the pressurized section of the SPM and add a new node/docking ball section.”

The proposal calls for this new node and docking ball section to be constructed from a Shuttle-salvaged Orbiter Docking System with added “flight-proven Boeing 702 satellite systems.”

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Together, this hybrid module and new node/docking ball section would “create an independent, fully functional vehicle with two NASA Docking Standard (NDS) systems for docking operations with visiting vehicles.”

Z22Following the launch and placement of the hybrid module and node/docking ball sections, the SLS with LUS would launch a crewed Orion spacecraft and habitat module (based off the remaining ISS Multi-Purpose Logistics Modules – MPLMs) in a single launch.

Following launch, the LUS would be used to conduct a translunar insertion burn to send Orion and the habitat module on their way to the proper location.

After departing Earth orbit, the Orion would detach from the main spacecraft, turn around 180 degrees (like Apollo used to during the moon landing missions), and then dock to the habitat module.

The combined Orion/habitat module vehicle would then separate from the expended LUS and fly to the SPM-derived core component of the Exploration Platform.

Z55The modified MPLM habitat module would have its Common Berthing Mechanism (CBM) replaced with an NDS and have its non-CBM end modified to include another NDS.

Its internal space would be modified to maximize habitable volume – something that wasn’t possible with the MPLMs’ use for transfer of removable racks to and from the ISS during Shuttle missions.

The new internal volume space would include: “crew living quarters, medical services, exercise equipment, a galley and payload facilities, as well as additional core systems hardware for redundancy.”

According to the Boeing presentation, “these three elements … form a very capable Exploration Platform that would enable and significantly enhance human operation in translunar space.

“Using the SLS/LUS would allow the Exploration Platform to be constructed and crewed in only two launches, as opposed to the four missions required using SLS/ICPS (interim Cryogenic Propulsion Stage), thus saving cost and significantly shortening the time required to start accruing the benefits of a crewed Exploration Platform in translunar space.”

SLS Mission: Large Crew Habitat Emplacement

Aside from the translunar outpost and Exploration Platform, Boeing also outlines the SLS/LUS duo’s launch ability for Bigelow’s BA-2100 inflatable habitat module.

“SLS allows delivery of the BA-2100 via direct insertion to a low earth orbit and is the only launch vehicle capable of delivering a payload this large to LEO,” notes the Boeing presentation.

Z9Bigelow’s BA-2100 inflatable module is considered a self-sufficient module for “long duration human habitation” capable of expanding, after launch, to 2100 cubic meters of pressurized volume.

The module itself would carry all the supplies and equipment needed for its mission, which can range from a commercial space hotel to a proving ground for independent scientific research modules.

For SLS/LUS’s part, the BA-2100 could be inserted directly in LEO (Low Earth Orbit).

Boeing further defines SLS as the only vehicle capable of launching BA-2100 into LEO because of the module’s large nature.

According to Boeing, “SLS provides significant mass margin [for BA-2100] that could be used for additional crew consumables or water for radiation protection or additional payloads.”

SLS mission: ATLAST Space Telescope Concept

Moving beyond the immediate Earth area, Boeing also identifies several beyond Earth missions that SLS could accomplish easier and in a more cost-effective manner than already existing launchers can.

One of these missions is a proposed ATLAST Space Telescope mission.

Z3Defined as a telescope to “Characterize Exoplanets and search for signs of life,” Boeing states that SLS would be able to loft this 8m monolithic or 16m deployable ATLAST telescope to the Earth-Sun L2 Lagrangian point in a single launch.

The current crop of existing EELVs (Enhanced Expendable Launch Vehicles – e.g. Atlas V and Delta IV) would require multiple launches and in-space assembly of the same type of telescope.

As presented in the Boeing presentation, “A monolithic aperture is better than a segmented aperture.”

Z8The currently under development James Webb Space Telescope (JWST) is using a segmented, deployed mirror architecture “only because it is the only way to launch a 6.5 meter aperture observatory with a 4.5 meter diameter rocket.”

Since a monolithic mirror can “achieve diffraction-limited performance at a shorter wavelength than a segmented mirror with much difficulty, complexity, cost and risk,” SLS is a more effective launcher for large-scale space telescopes.

Specifically, the Boeing presentation notes that the ATLAST telescope would be capable of observing “~85 stars 3 times each in a 5-year period, probe super massive black holes (SMBHs), conduct direct measurements of the mass of high redshift SMBHs, enable star formation histories to be reconstructed for hundreds of galaxies, track how and when galaxies assemble their present stars, and measure the mean density profile of dwarf spheroidal galaxies (dSph).

This type of telescope would have 10 times the resolution of the coming JWST and 300 times the resolution power of the Hubble Space Telescope.

SLS Mission: Solar Probe 2 Concept

Moving out ever further, Boeing identifies the SLS/LUS capabilities for a proposed Solar Probe 2 mission – the first probe capable of consistent and multiple close encounters with the sun.

Z4For this particular mission, Boeing states that “Solar Probe 2 will provide researchers both in-situ measurements and imagery supporting corona heating and solar wind acceleration investigations.”

The probe could also be used as part of a fleet of spacecraft to “develop critical forecasting capability of the space radiation environment in support of human and robotic exploration” of the solar system.

Specifically, the SLS/LUS duo would be capable of placing the Solar Probe 2 into a solar orbit with a low perihelion (minimum of 5 solar radii).

SLS Mission: Uranus Concept

Finally, Boeing outlines the 1.7mt payload delivery possibly of the SLS/LUS to planet Uranus.

Z5According to the presentation, the SLS with the LUS would be able to “Deliver a small payload into orbit around Uranus and a shallow probe into the planet’s atmosphere.”

The Uranian mission would be able to study the ice giant’s atmosphere and magnetic characteristics, identify the dispersal of heat emissions from Uranus’s atmosphere, perform close and detailed fly-bys of the planet’s moons (like Cassini currently does at Saturn), and improve our understanding of the “gravitational harmonics of the planet.”

Boeing states that utilization of SLS/LUS for this mission would not only shorten the travel time between Earth and Uranus, but also provide for the incorporation of increased spacecraft mass, thereby allowing for the elimination of the need for a Solar Electric Power stage to the payload.

(Images: Via L2 content from L2’s SLS specific L2 section, which includes, presentations, videos, graphics and internal – interactive with actual SLS engineers – updates on the SLS and HLV, available on no other site. Other images via NASA, Boeing)

(L2 is – as it has been for the past several years – providing full exclusive SLS and Exploration Planning coverage.  To join L2, click here:

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