Buoyed by the success of the Hubble Space Telescope, one of the key proposals on NASA’s internal interpretation of the Augustine Commission’s “Flexible Path” option includes a 45 day manned mission to construct a giant telescope in Geostationary orbit (GEO). A huge deep space telescope is also included in the roadmap, which would focus on a major advancement for the search of Earth-like planets.

Flexible Path/Massive Ambition:

The recently produced 64 page presentation – available on L2 – is being classed as heavily over ambitious by NASA sources, though it provides a fascinating insight into what NASA could do with a supporting budget.

Classed as an internal effort to “peel the onion” of the Augustine Commission option of the “flexible path” approach – several NASA centers and associated bodies were involved in providing insights to various options that could be open to the Agency, dependant on decisions that will be made by President Obama early this year.

Those centers, Ames Research Center (ARC), Glenn Space Flight Center (GSFC), Jet Propulsion Laboratory (JPL), Johnson Space Center (JSC) and the Hubble-related Space Telescope Science Institute (STScI) all contributed towards the findings.

“Ultimately the goal of this brief study is to arm NASA leadership with some specific, evocative examples of the type of missions that could be done – and how they might be ‘connected’ into a meaningful, practical program sequence – should NASA choose to pursue the Flexible Path strategy introduced by the Review of U.S. Human Spaceflight Plans Committee (Augustine Committee),” noted the presentation.

“When the inevitable question comes, ‘What exactly does the Flexible Path mean?’ these ideas may be useful.”

Creating an advanced path for huge space telescopes:

The presentation covers several areas, from the need for a heavy lift launcher, to manned missions to Mars and its moons – and also Near Earth Objects (NEOs), as the main elements (more articles will follow). However, a large section is also dedicated to the construction of large telescopes, with examples citing locations in LEO, GEO and in deep space.

Such an effort would involve a roadmap, which begins with large Hubble-type telescope in Low Earth Orbit (LEO).

“Stepwise progression advances both human space flight and telescope science,” opens the section. “Human/robotic assembly and servicing of large telescopes in space leads to breakthrough science and significant preparation for other deep-space human missions in stepwise fashion, beginning at ISS.

“LEO telescope assembly demonstrations would validate approaches for Modular Design, Human/Robotic Interaction, On-board Metrology, Autonomous Alignment/Control, and Contamination Control on a ‘small’ in-space telescope where the development environment timeline is relatively unconstrained, multiple EVAs, and subsystem alternatives can be exchanged. The end product would be an operational LEO telescope with larger aperture than HST.”

The GEO based telescope would become part of an approach that would also serve as a testbed for human space flight outside of LEO, including the first expedition outside of the geomagnetosphere’s radiation shielding.

“Next could be a GEO Earth Looking Observatory for applications such as Greenhouse Gas Monitoring, Attribution and Compliance; Persistent Intelligence, Surveillance and Reconnaissance; and other Earth Science,” the presentation continued.

“Construction and servicing in the GEO environment constitutes a first step for human space flight outside the geomagnetosphere’s radiation shielding.”

The final example involved with the roadmap is based around two Deep Space Telescope options, which would still involve human space flight.

“Deep Space Observatories are the goal for large-telescope science. A very large observatory at the Sun-Earth L2 point could capture breakthrough science in multiple areas: Earthlike Exoplanet Spectra, First Black Holes, VIS/IR Astrophysics, Life in the Galaxy, and Event Horizon Physics,” added the presentation.

“Such deep space observatories might best be assembled in the benign, relatively close region of Earth-Moon L1, and then carried to their operational location at SE L2 by a robotic low-thrust (ion propulsion) stage.

“Two options then open for subsequent human servicing, including system replenishment and instrument upgrades: the ion stage could return the observatory to EM L1, or a human mission could be mounted directly to SE L2. The latter case would demonstrate the expanding deep space capability of humans and their flight systems, and also avoid the long science down-time of relocating the observatory with a low-thrust system.”

Although such a roadmap is highly ambitious, the combination of advancements in science, and their dual purpose of pushing human space flight out of LEO, is something the participating centers deem to be viable based on the Flexible Path recommendations of the Augustine Commission.

“Having multiple steps on the path provides planning choices including schedule acceleration, combining of steps, or offramps to other types of human missions. For these reasons, and because of the unique benefits to large-aperture observational science attainable only with human space flight, we recognize these mission classes as viable for a Flexible Path strategy.”

While the presentation is deemed to be NASA internal, parts of the proposals are clearly aimed at both the general public and politicians – as the point is driven home about how “breakthrough science is enabled by constructing extremely large telescopes in space,” with the aim of finding the answer to the ultimate question – “are we alone?”

“Astrophysics is a photon-limited science. Many exciting investigations cannot be done with today’s space observatories simply because the targets are extremely faint, fainter by at least an order of magnitude than even the dimmest sources ever detected with HST or Chandra. Two of the most exciting questions that future space-based telescopes will address are “When did the first stars form?” and “Are We Alone?”

“The former question can be answered by searching for the black holes that the first stars leave behind when they die. These black holes would have formed when the universe was a mere 100 to 200 million years old (just about 1 percent of its current age!).

“To detect these black holes would require an x-ray telescope 1000x more sensitive than current facilities. But perhaps the most fundamental question of all is: Are We Alone? Are there planets around other stars where life as we know it has taken root?

“To answer this question requires a large Optical/IR (Infra Red) telescope for several reasons, but the two most significant ones are: (1) Earth-like planets even just 30 light years away will be extremely faint so we need a large telescope to obtain their spectra – which is where the signatures of life will be found; (2) if such planets are not common, we may need to search 100 or more stars before we find even a handful.

“The number of star systems where one can hope to obtain such spectra of Earth-sized planets in their stars’ Habitable Zone increases dramatically with the size of the telescope – as the telescope aperture doubles, the star sample increases by almost 8 times! Space telescopes with this much collecting area can only be assembled in space.”

Finding Black Holes – or the detectable remnants of the first Stars – would be increased from the current ability of finding 17 sources in one area of the sky, to a massive 3,000 sources via a large 50m2 X-Ray telescope in the same area.

Such an increase would be achieved via a 20-30m Vis/IR telescope, which would be capable of searching for the signature of life is encoded in Earth’s spectrum, as the “number of stars searchable for habitable worlds increases as the cube of telescope diameter.”

Constructing telescopes in GEO:

A combined human and robotic mission is outlined in detail, based around the construction of GEO observatory – four times the size of Hubble – with the focus on a 45 day mission for a crew using Orion.

In the scenario outlined, the “highly modular” telescope would be launched in two parts on two Ares V type heavy launchers.

The crew would launch in Orion – with the example shown of an Orion docked to a habitable module that includes an airlock, robotic arm and a payload box, riding on a stretched Centaur Upper Stage – though the graphic is possibly for “illustrative purposes” only.

“Example 1-2 month human mission: constructing Earth-looking GEO observatory. Astronauts assisted by robotic devices could construct a large observatory in geosynchronous orbit to enable persistent Earth Observation with unprecedented resolution,” notes the presentation.

“For example, this might be a 10-m class wide field telescope with scanning visible and IR cameras/spectrometers (for comparison, HST has a 2.4-m primary). The telescope design would be highly modular for ease of EVA (Spacewalk) assembly.

“The construction operations design would incorporate structured robotics to assist astronauts on repetitive and highgeometric-tolerance tasks. Example applications include: full Earth-disk scan imaging; high resolution Earth atmosphere spectroscopy; sourcelocalizing greenhouse gas monitoring, attribution & compliance; in-field agricultural monitoring; and Intelligence, Surveillance and Reconnaissance (ISR).

“Feed-forward technology opportunities include: modular observatory instrumentation/bus interfaces; contamination control; large lightweight mirror segments; on-board metrology and autonomous control; image based wavefront sensing; expandable sunshades; extended-use crew habitat, air locks, EVA suits, and robotic toolsets.”

The 45 day mission timeline shows the crew spending several days to travel to the worksite and prepare to complete the tasks in the following order: “Day 6: Unpack modules. Day 13: Assemble primary mirror. Day 17: Attach Secondary Mirror Tower. Day 19: Attach Metrology and Control Module. Day 23: Attach Instrument Module and S/C Bus. Day 25: Attach Sunshade and Baffles. Day 29: Autonomous Alignment. Day 31: Science Instrument Installation. Day 32: First Light. Day 35: Checkout,” before packing up and re-entry on Day 45.

Such a mission would “provide actionable information to support societal and critical national needs,” and would utilize a crew of four to six astronauts, carrying out around 20 EVAs.

“Astronauts assisted by robotic devices could construct a large observatory in geosynchronous orbit to enable persistent Earth Observation with unprecedented resolution. For example, this might be a 10-m class wide field telescope with scanning visible and IR cameras/spectrometers (for comparison, HST has a 2.4-m primary). The telescope design would be highly modular for ease of EVA assembly,” added the presentation.

“Feed-forward technology opportunities include: modular observatory instrumentation/bus interfaces; contamination control; large lightweight mirror segments; on-board metrology and autonomous control; image based wavefront sensing; expandable sunshades; extended-use crew habitat, air locks, EVA suits, and robotic toolsets.”

Also noted is the gain in public interest, who would be “engaged” throughout the 45 day mission.

“A strawman construction flow for the GEO Earth-looking observatory would use 4-6 astronauts, performing ~20 EVAs, over a 45-day period. Crew and cargo would be launched to a location on the geosynchronous arc, where assembly of pre-assembled modules proceeds as indicated in the arrowed flow.

“The mission duration estimate includes ample schedule margin, and recognizes that the particular modularity scheme, tools and human/robotic interfaces would be defined and validated in the ISS environment. Prior analyses leading to this notional mission description are based on HST servicing experience, JWST and AMD development, and conceptual designs of modular observatory systems. Checkout sensors and algorithms are at high TRL.

“Virtually every stage of the mission would yield public engagement milestones, and as HST has proven, the end result would be an unprecedented science system that ‘keeps on giving’ long after the crew has departed.”

Once again, the search for life on other planets is a key selling point of building large telescopes in space is again emphasized in the presentation.

“The path to constructing extremely large telescope in space moves humans progressively farther from the Earth, for longer durations in harsher environments. It involves a spectrum of progressively more complex capabilities from human EVA to locally controlled robotics, remotely controlled robotics, and autonomous robotics.

“Evolving capabilities are utilized to produce outcomes which feed forward to enable larger, more capable space observatories as well as expansion of humans into the solar system for other endeavors. Finally, it produces breakthrough science to answer fundamental questions of where we come from and whether we are alone.”

Interestingly, the telescope section of the presentation ends by claiming the construction of a deep space telescope can also be classed as the first step of a Flexible Path approach to NASA’s future.

“Constructing extremely large telescopes in space can be a first step on a Flexible Path, as it expands human space flight beyond LEO, develops progressive human/robotic capabilities, establishes needed technology and operations legacy, and enables breakthrough science.”

The required elements for the deep space telescope mission include the need for a heavy lift launch vehicle – though it is not stated if the requirement is for the much-touted 200mt launcher mentioned in other parts of the presentation.

Other capabilities listed include the hardware, such as tools and telescope elements, plus the robotic assist requirements and low thrust propulsion vehicles.

The presentation claims such a path would lead to a legacy, which includes deep space human operations, human/robotic interactions, modular assembly (outside of LEO), breakthrough science and national security.

How much each proposed mission would cost is not outlined in any part of the presentation.

L2 members: Documentation – from which the above article has quoted snippets – is available in full in the related L2 sections, now over 4000 gbs in size