A proposed exploration Gateway (Report: SELECTED!)

[Dr Mordrid]

US aerospace companies Boeing and Aerojet have presented NASA with an idea for a very low cost Exploration Gateway - a deep space space station/staging area for beyond Earth orbit (BEO) missions; fuel depots, Mars transfer, whatever.

The Gateway would be located at one of the two Earth-Moon Lagrange (EML) points (L1 or L2) after being constructed mostly from existing hardware at the ISS. Lagrange points are areas of gravitational equilibrium where spacecraft can be stationed with a much reduced need for station keeping fuel; they basically orbit an empty point in space.

Transferring spacecraft between such a Gateway and anywhere else in the solar system would require very little fuel compared to a brute-force launch from Earth. It's also ideal for transfer spacecraft powered by solar-electric ion and plasma drives, whose fuel loads are measured in the hunderds of kilograms instead of hundreds of tons.

Once constructed at ISS using an ISS Node 4/DHS (Docking Hub System), a Space Shuttle external airlock, an ISS MPLM (Multi-Purpose Logistics Module) habitat, and a new Russian Zvezda international module, it would be boosted to the selected Lagrange point by way of either a solar-electric (ion or plasma drive) or chemical propulsion module.

They claim the Exploration Gateway could be ready for BEO/Asteroid/Mars missions by 2022. Lunar missions would only need a (reusable?) lander to be built. Mars & asteroid transit vehicles could be assembled at the Gateway using modules lofted by cheap launchers.

IMO: if it works - build another at Mars and just move crew transfer and cargo vehicles between the Gateways.

[VJ]

Just out of curiosity: wouldn't it have been possible to keep one or even two space shuttles in space to transfer cargo between e.g. ISS and these gateways?
The ceramic tiles problem would not matter, it has maneuvering thrusters, docking capabilities and a huge cargo bay, robotic arm things, ...

[Jammrock]

The problem is getting them up there. The program has been scrapped and it would probably cost a fortune to rebuild it.

[Umfriend]

VJ, you mean keeping the shuttles up there for ever?

[KRSESQ]

You'd lose quite a bit of the cargo hold to fuel tanks if you wanted to modify a space shuttle in such a way. It probably could have been done but whether it would have been cost-effective compared to a new-generation reusable vehicle is questionable.

(Unless you simply retained the external tank for that purpose, in which case you'd be lugging around a lot of extra mass.)

Not to mention the on-orbit maintenance a modified orbiter would require.

[Dr Mordrid]

The Shuttles are gone; their systems have been removed, the engines and thruster assemblies removed and replaced with models, their (toxic) fuel plumbing and hydraulics have been stripped and their shells are being prepped for museum display. The external tank factory at Michoud Louisiana is retooling to make the first stage of the Space Launch System (SLS), and SRB maker ATK has retooled to make a larger version using a different fuel grain for SLS.

There is no going back. Besides....

Shuttles require fuel cells for life support & power, limiting their missions to <2 weeks, then there is the problem that made them a bad idea to begin with: to haul 24 MT of cargo you have to use enough fuel to move a 100 MT spacecraft too. By the time you add enough extra hypergolic fuel for its thrusters and OMS engines to even make one trip....

Better to use a minimalist ~5-10 MT robotic solar electric tug launched on a cheap Falcon 9 to haul the same mass. With a few hundred kg of fuel (argon, etc.) it could make many round trips to the Gateway. Aerojet makes such thrusters, and they have a long flight history.

[Dr Mordrid]

The plot thickens....first there was this proposal for an Exploration Gateway built largely from existing hardware by Boeing -

http://www.nasa.gov/pdf/604659main_6%20-%20Panel%203_Raftery_Final.pdf

and now this -

NBC....

NASA considers outpost beyond moon's far side

NASA is pressing forward on assessing the value of a "human-tended waypoint" near the far side of the moon — one that would embrace international partnerships as well as commercial and academic participation, Space.com has learned.

According to a Feb. 3 memo from William Gerstenmaier, NASA's associate administrator for human exploration and operations, a team is being formed to develop a cohesive plan for exploring a spot in space known as the Earth-moon libration point 2 (EML-2).

Libration points, also known as Lagrangian points, are places in space where the combined gravitational pull of two large masses roughly balance each other out, allowing spacecraft to essentially "park" there.

A pre-memo NASA appraisal of EML-2, which is near the lunar far side, has spotlighted this destination as the "leading option" for a near-term exploration capability. [Gallery: Visions of Deep-Space Station Missions]

EML-2 could serve as a gateway for capability-driven exploration of multiple destinations, such as near-lunar space, asteroids, the moon, the moons of Mars and ultimately Mars itself, according to NASA officials.

A capabilities-driven NASA architecture is one that should use the agency's planned heavy-lift rocket, known as the Space Launch System, and the Orion Multi-Purpose Crew Vehicle "as the foundational elements."

The memo spells out six strategic principles to help enable exploration beyond low-Earth orbit:

• Incorporating significant international participation that leverages current International Space Station partnerships.

• U.S. commercial business opportunities to further enhance the space station logistics market with a goal of reducing costs and allowing for private-sector innovation.

• Multi-use or reusable in-space infrastructure that allows a capability to be developed and reused over time for a variety of exploration destinations.

• The application of technologies for near-term applications while focusing research and development of new technologies to reduce costs, improve safety and increase mission capture over the longer term.

• Demonstrated affordability across the project life cycle.

• Near-term mission opportunities with a well-defined cadence of compelling missions providing for an incremental buildup of capabilities to perform more complex missions over time.

The Lagrange points for the Earth-moon system are the places where the gravitational pull exerted by the two celestial bodies balances out. NASA is evaluating an early mission with the Orion capsule placed at Earth-moon L2. Astronauts parked there could teleoperate robots on the lunar far side.

According to strategic space planners, an EML-2 waypoint could enable significant telerobotic science on the far side of the moon and could serve as a platform for solar and Earth scientific observation, radio astronomy and other science in the quiet zone behind the moon.

Furthermore, the waypoint could enable assembly and servicing of satellites and large telescopes, among a host of other uses.

If NASA succeeds in establishing an astronaut-tended EML-2 waypoint, it would represent the farthest humans have traveled from Earth to date, the memo points out.

Extended stays at EML-2 would provide advancements in life sciences and radiation-shielding for long-duration missions outside of the Van Allen radiation belts that protect Earth, scientists say.

Gerstenmaier noted that moving forward on international, commercial and academic partnerships will "require significant detailed development and integration."

Moreover, Gerstenmaier added, EML-2 "is a complex region of cis-lunar space that has certain advantages as an initial staging point for exploration, but may also have some disadvantages that must be well understood."

Study due by April

A NASA study team is assigned the task of developing near-term missions to EML-2 "as we continue to refine our understanding and implications of using this waypoint as part of the broader exploration capability development," the memo explains.

The study is targeted for completion by March 30.

A working group of International Space Station members — a meeting bringing together space agencies from around the world — was held in Paris last week, and NASA’s EML-2 strategy was expected to come up.

Bullish on the promise of telerobotics exploration of the moon from EML-2 is Jack Burns, director of the Lunar University Network for Astrophysics Research (LUNAR) Center at the University of Colorado, Boulder. LUNAR is funded by the NASA Lunar Science Institute.

Burns and his team have been collaborating with Lockheed Martin (builder of the Orion Multi-Purpose Crew Vehicle) for more than a year to plan an early Orion mission that would go into a halo orbit of EML-2 above the lunar far side.

"This is extremely exciting from both the exploration and science sides," Burns told Space.com. "This mission concept seems to be really taking off now because it is unique and offers the prospects of doing something significant outside of low-Earth orbit within this decade."

Proving ground in deep space

In collaboration with Lockheed Martin, the LUNAR Center is investigating human missions to EML-2 that could be a proving ground for future missions to deep space while also overseeing scientifically important investigations.

In a LUNAR Center white paper provided to Space.com, researchers note that an EML-2 mission would have astronauts traveling 15 percent farther from Earth than did the Apollo astronauts, and spending almost three times longer in deep space. [Lunar Legacy: Apollo Moon Mission Photos]

Such missions would validate the Orion spacecraft's life-support systems for shorter durations, could demonstrate the high-speed re-entry capability needed for return to Earth from deep space, and could help scientists gauge astronauts’ radiation dose from cosmic rays and solar flares. Doing so would help verify that Orion provides sufficient radiation protection, as it is designed to do, researchers said.

On such missions, the white paper explains, Orion astronauts could teleoperate gear on the lunar far side. For instance, the moon-based robotic hardware could obtain samples from the geologically appealing far side — perhaps from the South Pole-Aitken basin, which is one of the largest, deepest and oldest craters in the solar system.

Also on a proposed lunar robotic agenda is deployment of a low-frequency array of radio antennas to observe the first stars in the early universe.

Among a number of research jobs, the LUNAR team has been investigating how modest equipment could be used to fuse lunar regolith into a concretelike material, which could then be used for construction of large structures, without the expense of having to carry most of the material to the lunar surface.

The robotic rollout of an antenna, shown in this artist's conception, would be aimed at creating an array of low-frequency radio antennas to observe the first stars in the early universe.

The ability to fabricate hardened structures from lunar regolith could also foster on-the-spot creation of solar arrays, habitats, and radiation shielding and maybe, even roadways on the surface of the moon.

[Evildead666]

Lets hope they do this ASAP and without leaking billions of dollars on the way.

Give it to SpaceX to manage ;-)

[Dr Mordrid]

Orlando Sentinel -

http://articles.orlandosentinel.com/2012-09-22/news/os-nasa-space-outpost-20120922_1_moon-rocks-space-launch-system-nasa-chief-charlie-bolden

Sentinel Exclusive: NASA wants to send astronauts beyond the moon

WASHINGTON — Top NASA officials have picked a leading candidate for the agency's next major mission: construction of a new outpost that would send astronauts farther from Earth than at any time in history.

The so-called "gateway spacecraft" would hover in orbit on the far side of the moon, support a small astronaut crew and function as a staging area for future missions to the moon and Mars.

At 277,000 miles from Earth, the outpost would be far more remote than the current space station, which orbits a little more than 200 miles above Earth. The distance raises complex questions of how to protect astronauts from the radiation of deep space — and rescue them if something goes wrong.

NASA Chief Charlie Bolden briefed the White House earlier this month on details of the proposal, but it's unclear whether it has the administration's support. Of critical importance is the price tag, which would certainly run into the billions of dollars.

Documents obtained by the Orlando Sentinel show that NASA wants to build a small outpost — likely with parts left over from the $100 billion International Space Station — at what's known as the Earth-Moon Lagrange Point 2, a spot about 38,000 miles from the moon and 277,000 miles from Earth.

At that location, the combined gravities of the Earth and moon reach equilibrium, making it possible to "stick" an outpost there with minimal power required to keep it in place.

To get there, NASA would use the massive rocket and space capsule that it is developing as a successor to the retired space shuttle. A first flight of that rocket is planned for 2017, and construction of the outpost would begin two years later, according to NASA planning documents.

Potential missions include the study of nearby asteroids or dispatching robotic trips to the moon that would gather moon rocks and bring them back to astronauts at the outpost. The outpost also would lay the groundwork for more-ambitious trips to Mars' moons and even Mars itself, about 140 million miles away on average.

Placing a "spacecraft at the Earth-Moon Lagrange point beyond the moon as a test area for human access to deep space is the best near-term option to develop required flight experience and mitigate risk," concluded the NASA report.

From NASA's perspective, the outpost solves several problems.
It gives purpose to the Orion space capsule and the Space Launch System rocket, which are being developed at a cost of about $3 billion annually. It involves NASA's international partners, as blueprints for the outpost suggest using a Russian-built module and components from Italy. And the outpost would represent a baby step toward NASA's ultimate goal: human footprints on Mars.
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[KRSESQ]

Provided the L points aren't full of crap that could constitute a collision hazard. We'll probably find all kinds of old rocket junk out there.

[Dr Mordrid]

L4 and L5 are the L-points where space junk & small objects passively collect, this due to the suns influence and their 60° angle relative to the Moon-Earth-Sun baseline. They behave like a gravitational bowl stuff falls into. Once there's a good space housekeeping system thes could work, but not now plus there's the distance factor.

L1, L2 and L3 are the opposite - each points attraction is relatively weak, and left alone objects in an orbit around them (a halo orbit) will drift away, necessitating station keeping thrusters. A much safer location for a Gateway, and ion or plasma thrusters should do, minimizing the needed fuel mass.