NASA and the Search for Technosignatures: A Report from the NASA Technosignatures Workshop

Brief

Convened September 26–28, 2018 at the Lunar and Planetary Institute in Houston, the workshop drew approximately 60 researchers from academia, government labs (JPL, GSFC, NASA Ames), and the private sector (Breakthrough Listen, SETI Institute, METI International) to address four goals: characterize the current state of technosignature searches, assess near-term assets, identify future opportunities, and scope NASA partnership roles. The report documents upper limits on continuous-wave radio, pulsed radio, optical/NIR laser, waste heat, megastructure transit, and solar-system artifact searches, while flagging that rigorous cross-team comparison is blocked by inconsistent statistical frameworks and the total absence of community data challenges or injection-recovery benchmarks. The field's institutional thinness is quantified directly: no regular federal funding for decades, fewer than 10 PhDs ever awarded in the discipline, and the most recent comprehensive review a 2001 ARAA article by Jill Tarter covering radio SETI only.

Metadata

Category

Hub & Overview

Venue

preprint (arXiv astro-ph)

Type

NASA technical report

Year

2018

Authors

Jason T. Wright, Dawn Gelino

arXiv

1812.08681

Access

Open access

Length

3.8 M

Programs

Breakthrough Listen, Breakthrough Initiatives, SETI Institute, METI International, PLANETS Foundation, Blue Marble Space Institute

Instruments

Big Ear (Ohio State University)

Tags

SETI, technosignature, biosignature, astrobiology, radio-SETI, optical-SETI, waste-heat, megastructures, Dyson-spheres, research-roadmap, upper-limits

Key points

• Workshop convened September 26–28, 2018 at the Lunar and Planetary Institute, Houston, described as the first major US government-convened technosignature assessment in decades, organized around four explicit goals covering state of field, near-term assets, future opportunities, and NASA partnership roles.p.4
• The term 'technosignatures' entered scientific literature only with Jill Tarter's 2007 article; the report defines them as any detectable sign of technology capable of inferring the existence of intelligent life elsewhere in the universe.p.5
• Fewer than 10 PhDs have been awarded for dissertations on searches for technosignatures, and there is virtually no graduate-level curriculum on the subject, a direct consequence of decades without regular federal funding.p.8
• The last comprehensive review of the technosignature field before this report was a 2001 Annual Review of Astronomy and Astrophysics article by Tarter, focused solely on radio SETI.p.8
• Nine 'axes of merit' for evaluating technosignature search strategies, timeliness, cost, ancillary benefit, duty cycle, ambiguity, degree of extrapolation, contrivance, detectability, and detection utility, were consolidated by Sofia Sheikh into a figure presented on the workshop's final day.p.6
• No agreed-upon community standard exists for defining a radio technosignature upper limit; teams have not shared data for algorithm benchmarking, performed Monte Carlo injection-recovery tests, or organized data challenges to compare methodologies across programs.p.13
• Waste heat from technology has a similar observational signature to astrophysical dust, making discrimination difficult; narrow-band radio emissions, by contrast, have no plausible natural coherent source below physical maser limits.p.7
• Because many technosignatures are self-luminous or harness bright natural energy sources, they may be detectable at extragalactic distances, a structural detectability advantage over virtually all biosignature strategies.p.5

Verbatim

• “If we can find technosignatures—evidence of some technology that modifies its environment in ways that are detectable–then we will be permitted to infer the existence, at least at some time, of intelligent technologists.”

  p.5

• “Every search for alien civilizations should be planned to give interesting results even when no aliens are discovered.”

  p.6

• “Compared to biosignatures, technosignatures might therefore be more ubiquitous, more obvious, more unambiguous, and detectable at much greater (even extragalactic) distances.”

  p.5

• “Astro-physicists...spent decades studying and searching for black holes before accumulating today's compelling evidence that they exist.”

  p.12

• “much of the literature on technosignature limits is contained in conference proceedings and unrefereed journals, if it appears anywhere at all, and so upper limits can only be deduced from approximations and guesses about a given survey's properties, algorithms, and the fact that they did not announce a detection.”

  p.13

Most interesting

• The word 'technosignatures' did not appear in scientific literature until Jill Tarter introduced it in 2007, less than two decades before NASA convened its first workshop on the subject.
• Freeman Dyson's 'First Law of SETI Investigations', that every search should yield interesting results even absent a detection, was cited as a formal organizing principle for scoring search strategies on the ancillary-benefit axis.
• The 'Cosmic Haystack' framing, treating signal detection as a multi-dimensional search volume problem, was first quantified by Wolfe et al. (1981) and extended by Tarter (2001) and Wright et al. (2018).
• A 'file-drawer' problem is explicitly named: null-result technosignature searches were historically not accepted to prestigious journals, and for the field's first several decades some journals refused to publish technosignature work at all.
• The Wow! signal, received at Ohio State University's Big Ear radio telescope and discovered by astronomer Jerry R. Ehman, is cited in the report as a canonical example of how one-off detections resist upper-limit formalization.
• Technosignature searches are characterized as 'dual-use' across nearly all of NASA's current, planned, and contemplated planetary science and astrophysics missions, offering a rare chance to integrate a science goal into the portfolio from the outset rather than retrofitting it later.