Precision Astrometry Using Optically Independent Spacecraft for Graviational Wave Detection

Precision Astrometry Using Optically Independent Spacecraft for Graviational Wave Detection

1 min read

Preparations for Next Moonwalk Simulations Underway (and Underwater)

Labeled diagram of Graviational Wave Detection
Graphic depiction of the Graviational Wave Detection concept.
Paul Stankus

Paul Stankus
Brookhaven Science Associates 

The scientific goal is to enable a new method for observing gravitational waves at low frequencies, based on the astrometric GW signature — gravitational waves passing by the Earth will cause a (very small) coordinated apparent motion of all sky objects. Our innovation is to deploy a new approach to precision astrometry using quantum mechanical two-photon interference, which was published quite recently. The approach has the great benefit that two separate interferometric spacecraft stations can operate independently, ie without an optical connection between them, greatly simplifying spacecraft requirements compared to standard space-based interferometric designs. With this capability we propose to be able to detect passing gravitational waves at low frequencies, in the micro-Hz to nano-Hz range, at a sensitivity at an astronomically interesting level (note that there are, currently, essentially no alternative approaches for GW detection in this band). We show how this could be achieved with a straightforward mission using two modest-sized spacecraft in free-fall orbits; and detection of such GW’s would be of great interest for galaxy formation and SM black hole physics, as well as exciting the public imagination.

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Jul 21, 2026

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Loura Hall

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Mapping Alien Continents: Achieving Optical VLBI for Exoplanet Imaging 

Mapping Alien Continents: Achieving Optical VLBI for Exoplanet Imaging 

1 min read

Preparations for Next Moonwalk Simulations Underway (and Underwater)

Labeled diagram of Exoplanet Imaging
Graphic depiction of the Mapping Alien Continents concept.
Paul Stankus

Paul Stankus
Brookhaven Science Associates

The scientific goal of the proposed work will be reconstructing the image, ie resolving surface features, of an Earth-like exoplanet around a nearby star as seen in visible light. The innovation is in two stages. First, the design of a new kind of nulling interferometer — “dynamic hierarchical nulling” — combining inputs from multiple apertures and capable of separating star light from planet light with contrast of 10^10 or better in the visible. Second, combine the output beams from two such nullers on spacecraft stationed ~100km apart to achieve the required angular resolution using Michelson interferometric imaging; note that the hierarchical nuller preserves the star’s light in a separate beam which can then be used as in interference phase reference. The capability to survey the features of Earth-like exoplanets is perfectly aligned with NASA priorities and sure to excite public interest.  

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Loura Hall

Interworld Slingshot Resource Surveys

Interworld Slingshot Resource Surveys

3 min read

Preparations for Next Moonwalk Simulations Underway (and Underwater)

Graphic depiction of the Interworld Slingshot Resource Surveys concept.
Pablo Sobron

Pablo Sobron Sanchez
SETI Institute

This proposal explores a new class of reconnaissance spacecraft that map minerals from orbit using Raman spectroscopy during high-speed flybys–without landing, sample return, or extended dwell. If feasible, this concept would enable NASA to evaluate ice and ilmenite at the Moon, ore content at asteroids, and volatile-bearing minerals at Mars’ moons–all with a single 300-kg spacecraft. The capability addresses NASA’s long-term goals in sustainable lunar presence, asteroid resource evaluation, and Mars logistics by answering a key operational question: what exactly is this material?  

The central objective is to determine whether Raman spectroscopy–a technique that identifies minerals by their molecular fingerprints–can operate from tens of kilometers away during flyby or orbital arcs. To date, planetary Raman has only been used from meters away on rovers. Performing Raman from 30–50 km standoff would open a new regime for planetary science and space resource mapping, delivering the compositional specificity that passive reflectance or neutron methods cannot.  

The reference mission concept uses a single solar electric propulsion spacecraft to conduct three reconnaissance legs: (1) 50 km polar orbit of the Moon to map ice and ilmenite; (2) a 30 km flyby of a near-Earth asteroid to identify silicates, metals, and organics; (3) a 30—50 km orbit of Phobos or Deimos to detect volatile-rich phases that inform Mars mission logistics.  

At each leg, a high-energy pulsed laser, time-gated photon-counting detector, and rad-class beam steering system isolate Raman signals from the planetary surface. No existing sensor or mission class can perform this function.  

To determine feasibility, this NIAC Phase I study answers three core questions: (1) Can key mineral Raman lines be detected with adequate signal-to-noise from 50 km? (2) Can beam pointing and smear be stabilized during fast flybys to allow integration over dwell time? (3) Can a 300-kg spacecraft with realistic propulsion, power, and attitude control systems close the mission architecture across all three destinations?  

Methods include first-principles photon modeling based on known Raman cross-sections, spacecraft jitter analysis, and trajectory design using NASA’s standard mission planning tools. The study is divided into three technical work packages plus synthesis and reporting. Sensitivity analyses and decision gates are built in to determine how changes in photon return or pointing control would affect overall mission viability. Alternative architectures are explored for each leg, including lower flyby altitudes and different propulsion schemes.

The study team combines deep expertise in Raman instrumentation, spaceborne lidar, and mission design. PI Sobron led field 120-meter-range Raman systems and contributed to SuperCam and SHERLOC on Mars. Co-I Lee and Collaborator Yu from NASA Goddard bring direct heritage from ICESat-2 and other orbital laser systems. Co-I Casell at NASA Ames leads early mission design and brings prior NIAC experience. The team is supported by SETI and OffWorld, a commercial partner.  

If successful, the work will define the first architecture for orbital Raman mineral detection and demonstrate that high-resolution molecular mapping is possible without landing. Even partial success would establish new boundaries for remote sensing physics, provide validated models, and support future NASA decisions in Artemis siting, asteroid mining, and Mars ISRU planning. The architecture enables a cost-effective Discovery-class template that could eventually scale to a fleet of inner Solar System scouts–bringing Landsat-style mineral intelligence to planetary exploration.

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Psyche Approaches Mars

Psyche Approaches Mars

This composite of images taken by NASA’s Psyche mission shows the crescent of Mars grow as the spacecraft approached the planet for a gravity assist from May 2 to May 15, 2026. Because Psyche approached Mars from a high phase angle, the planet appeared as a thin crescent in the days running up to the close approach, lit by sunlight reflecting off its surface.

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Robotically Assembled Electromagnetic Metamaterials for Long-Range Space Situational Awareness 

Robotically Assembled Electromagnetic Metamaterials for Long-Range Space Situational Awareness 

3 min read

Preparations for Next Moonwalk Simulations Underway (and Underwater)

Graphic depiction of the Robotically Assembled Electromagnetic Metamaterials concept.
David Smith

David Smith
Duke University 

The increasing population of spacefaring vehicles and satellites motivates increasingly powerful technologies for space situational awareness (SSA). While the US space surveillance network (SSN) is able to monitor objects down to about four inches in size using, for example, the latest upgrade to the space fence, the associated requirements limit implementation to ground-based tracking of low earth orbit (LEO) objects using kilometer-scale radar arrays. Beyond LEO, the prospect of cislunar traffic and the extreme distances involved render ground-based arrays impractical. This limitation is fundamental to coherent radar systems: for a given detection performance, the required array size grows in direct proportion to the target distance. As a result, it can in fact become simpler to decrease the sensing distance rather than extend array sizes, and this can only be achieved by shifting to a space-based SSA platform.  

Although space-deployed radar systems offer distinct advantages in terms of sensing capabilities, the large distances associated with cislunar surveillance still require extremely large apertures for adequate performance. This poses significant practical challenges based on limitations to modern deployable structures which, to date, cannot consistently achieve dimensions greater than 100 meters. This limitation arises because state-of-the-art deployable antennas, including membrane, mesh, and inflatable architectures, require the entire structure to be housed inside a single launch fairing. In contrast, the prospect of in-space assembly suggests the potential for scalable structures that are not limited by launch constraints and so can meet the challenging requirements of long-range SSA.  

We propose a spaceborne radar system that pairs the demonstrated performance of robotically assembled mechanically stable structures with reconfigurable, volumetric electromagnetic metamaterials. The former technology enables modular and precise construction of arbitrary volumetric structures, while the latter offers a sophisticated and readily compatible design platform for achieving the challenging requirements of long-range SSA. Both approaches exploit a unit cell-driven, modular design procedure that enables nearly arbitrary scaling for mechanically and electromagnetically robust antenna platforms. The ability to reliably assemble and control volumetric antenna structures in this way provides access to new and powerful capabilities including steering over wide fields of view (FOV) without the need for slow, mechanical slewing of the antenna.  

The proposed work will demonstrate the feasibility and scalability of a reconfigurable, volumetric S-band metamaterial for achieving various beam steering capabilities. This effort will include advancement of metamaterial design strategies for omnidirectional electromagnetic beam forming and initial assessment/design of a reconfigurable unit cell compatible with robotic assembly. The development of the metamaterial design procedure will exploit a numerically efficient dipole model that has been previously validated at smaller scales, while the metamaterial element design will proceed by established full-wave numerical methods. System design concepts will incorporate practical constraints according to successful demonstrations of robot assembly by the Automated Reconfigurable Mission Adaptive Digital Assembly Systems (ARMADAS) project.  

While the project will target SSA applications, the design considerations involved are equally applicable to missions requiring large physical apertures such as low-frequency radiometry for earth observation and deep-space communications. Since the performance (resolution, sensitivity) of all beam steering, radar, and observation missions improves with increased aperture sizes, the realization of alternative electromagnetic strategies that offer reduced CSWaP can provide advantages across a wide range of NASA programs. 

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Jul 21, 2026

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Loura Hall

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