What is the NASA Habitable Worlds Observatory? Inside the One-Up Webb plan

A little over a year ago, when NASA’s James Webb Space Telescope went live, dominating the headlines of even the mainstream media, it seemed like the start of a new era. Equipped with infrared sensors and crowned with 18 gold-coated mirrors, JWST reminded the world that even though most of us are stuck on Earth, Home Base isn’t all we have to explore.

After the runaway success of JWST, NASA officials have shocked us with their sci-fi blueprints for a planetary defense system. They also managed to kick off the modern Apollo years with the Artemis I mission to the Moon — no matter the cost — and even began building a warehouse to drop rock samples on Mars reminiscent of scenes from Star Trek. And in early January, during the 241st meeting of the American Astronomical Society, NASA announced its plans to continue fueling a welcome reinvigoration of the US space program.

But of all that has been introduced, what seems to have attracted quite a bit of public interest (including mine) is an update to the so-called Habitable Worlds Observatory.

Simply put, this telescope is expected to stare out into the universe, detect an amazing range of wavelengths of light in deep space and even be serviceable in outer space, where it will, in fact, sit next to its predecessor, the JWST.

The ultimate goal of this machine? Discover a planet with alien life as soon as possible.

jwst-1. jpg

An artist’s impression of the James Webb Space Telescope, a joint project of NASA, the Canadian Space Agency and the European Space Agency.

ESA/ATG medialab

Sound familiar?

Since the 1990s, thanks to amazing innovations like NASA’s Transiting Exoplanet Survey, scientists have discovered a staggering number of exoplanets that range from Earth twins to water worlds, worlds that rain diamonds to oddly shaped rugby balls and even places that literally remind us of hell.

A handful of these are considered “habitable,” which means they likely have evidence of, at the very least, ancient microbial remains. life as we know it. But we have not yet found a world where such life exists, or has ever existed.

NASA’s Habitable Worlds Observatory, which the agency expects to launch in the 2040s, will be built specifically to obtain that certainty of life beyond Earth.

As Mark Clampin, director of the agency’s Astrophysics Division, said during NASA’s recent AAS meeting, the primary science goal for this observatory will be to “scan nearby stars for habitable planets and characterize them as evidence of life.”

NASA's silver TESS spacecraft in illustration with Earth and Moon in the background.

Illustration of NASA’s TESS spacecraft.


The impetus for this project is a report called the Astro2020 Survey of the Decade, published in November 2021 by US advisors with the National Academies of Sciences, Engineering, and Medicine.

In short, this report emphasized three “major scientific challenges” that humanity must grapple with over the next decade. Two of them relate to finding new kinds of physics in the universe (think, particles and exotic objects) and improving our understanding of the origins and evolutions of galaxies.

But a third challenge — and the one the organization is leading — is to identify habitable Earth-like worlds in other planetary systems and determine whether life exists elsewhere in the universe.

In other words, it is the answer to the question: Are we alone?

“In the past decade, uncertainty in the number of potentially habitable Earth-sized planets has been reduced by Kepler and other missions, and such planets are now known to be common. An improved understanding of the complexities of planetary atmospheres allows us to determine the spectroscopy measurements needed to assess the signatures of life.” , mentioned the 2021 report.

So, in response to the contract’s recommendations, NASA created what it called the Great Observatory Technology Maturity Program, or GOMAP.

As reported by SpaceNews’ Jeff Foust, Clampin said the first three phases of GOMAP — which relate to regulation and policy making — are almost complete. He explained that Phase Two will delve deeper into the habitable worlds mission.

“We can develop a wide range of missions to pursue visionary goals, such as searching for life on planets orbiting stars in our galactic neighborhood — while exploiting the richness of 21st century astrophysics through a multicolored fleet,” said Fiona Harrison, Physics Department Chair. and mathematics and astronomy at Caltech, and co-chair of the steering committee on the National Academies Statement on the 2021 Report.

As I mentioned earlier, the Habitable Worlds Observatory is expected to launch sometime in 2040s, Unless the agency is able to bring the deadline closer. Which can happen.

Foust reported that during a Jan. 11 conference session at the AAS, Jason Tomlinson, an astronomer with the Space Telescope Science Institute, suggested ways to shift budgets to bring forward a faster deadline for the observatory. Overall, these modifications could move the first HWO mission until 2035.

Although the possible launch of HWO is so far in the future, we don’t know much about what it will look like.

Here’s what we know so far

At this point, based on what was requested by the 2021 Decadal Survey, HWO is expected to be a roughly 6-meter telescope (or 20 feet, roughly the size of JWST) operating in the ultraviolet, visible, and near-infrared wavelengths of the electromagnetic spectrum.

Visible wavelengths are those we can see with our eyes, ultraviolet is Hubble’s specialty and infrared is the James Webb Space Telescope’s expertise.

The report — which draws notably on ideas from what appears to be an earlier version of the HWO called NASA’s Habitable Exoplanet, or HabEx — also indicated that such an observatory would cost nearly $11 billion. This is about $1 billion more than the cost of JWST.

A diagram of the electromagnetic spectrum, showing the regions that Hubble and Webb can see.

This graph shows the spectrum of electromagnetic energy, specifically highlighting parts detected by the NASA Hubble, Spitzer and Webb space telescopes.

NASA and J. Olmsted [STScI]

And as for where the Habitable Worlds Observatory will be stationed, it might be JWST’s new neighbor — as Clampin said, it will be sent to the second Lagrangian point, precisely where the current glass man sits. The second Lagrangian point, or L2, is a point of gravitational equilibrium between Earth and the sun a million miles away.

L2 is very ideal for spaceborne robots as it can anchor it in orbit around our bright yellow star while at the same time shielding it from the sun’s radiation.

And impressively, the main update that will set HWO apart from JWST is the fact that this future observatory will most likely be “serviceable.” This means NASA will be able to robotically service and improve the telescope even when it’s locked in space at L2 — extending its life and adorning it with power-ups as if it were straight out of a video game.

JWST does not have this option. Theoretically, if something happens to the JWST, scientists won’t be able to completely fix it.

The Hubble Space Telescope, floating close to us since it’s currently in Earth’s orbit, was a symbol of its serviceability—the public was fascinated by watching the fit scientists climb over the ‘scope’ and tweak its components in the air. This is actually part of how it got its beloved name: the People’s Telescope.


Webb orbits the sun 1.5 million kilometers (1 million miles) from Earth at what’s called a second Lagrangian point, or L2. Note: This drawing is not to scale.


So what can we expect HWO to find? As indicated in the Decadal Survey, we hope that this future observatory will be able to detect approximately 25 potentially life-threatening exoplanets, a sample size that the authors say will provide “strength against uncertainties in the rate of occurrence of Earth-size worlds, and against associated fluctuations.” with certain near-Earth systems.

To sum it up, the report basically says that HWO could be a compromise between HabEx and a scaled-down version of NASA’s Luvoir concept, or the Large Optical Ultraviolet Telescope.

The latter has a launch date of mid-2030 and is also expected to be serviceable, but is much larger than the 6m.

Her hypothesis is also more general than HWO appears to be – “Luvoir’s wide range of capabilities, including its wide UV-NIR wavelength range, will allow it to study phenomena that have yet to be discovered and answer yet dreamy questions we don’t yet know how to ask.” says the agency in an overview of Louvoir’s mission.

Again though, HWO isn’t expected to touch the skies for at least another decade or so – more if the mission encounters the same hurdles as Artemis.

This does not mean that NASA’s new era of space exploration will stop, of course. This year alone, we have a lot to look forward to.

Leave a Comment