How can we bring down the costs of large space telescopes?

We’re all basking within the success of the James Webb House Telescope. It is fulfilling its promise as our strongest telescope, making every kind of discoveries that we have been anticipating and hoping for. However the JWST’s story is one in every of damaged budgets, repeated requests for extra money and time, and near-cancellations.

Can we make space telescopes inexpensive?

The JWST is barely a yr into its mission and we’re already anticipating the following space telescopes. NASA is already planning and creating the Nancy Grace Roman House Telescope (previously WFIRST) and the Liveable Worlds Observatory (previously LUVOIR) for launch in 2027 and the late 2030s, respectively.

These space telescopes will doubtless be extraordinarily costly. Nevertheless, a workforce of researchers thinks there are methods to carry the price of space telescopes down. They’ve written a paper presenting their ideas titled “Approaches to decreasing the price of giant space telescopes.” The lead writer is Ewan Douglas, an Assistant Professor of Astronomy on the College of Arizona, Steward Observatory. They introduced their paper on the SPIE Optics + Photonics 2023 convention in August. It’s out there on the arXiv preprint server.

There is not any doubting the scientific rationale for big space telescopes. They ship outcomes unattainable to get in every other approach. There’s additionally no doubting their expense and their drain on NASA’s price range. They will by no means be cheaper than ground-based telescopes, however ground-based telescopes merely cannot carry out the way in which space telescopes can.

No one needs to surrender the scientific progress stemming from highly effective space telescopes. However it’s onerous to counter the criticisms that they are getting too costly. Douglas and his co-authors have some concepts on how we will proceed to generate new discoveries with space telescopes whereas making the fee extra palatable.

Their paper focuses on a hypothetical 6.5 m mirror optical light that operates in space at room temperature. 6.5 meters is similar measurement because the JWST’s mirror. They present how some applied sciences have gotten cheaper, how some know-how that was innovative is now almost off-the-shelf, and the way spacecraft like SpaceX’s Starship means we will launch telescopes with bigger major mirrors with out constructing advanced, costly mirrors just like the James Webb’s.

Floor-based telescopes noticed a pronounced drop in prices after 1980, and the researchers say the identical factor can occur with space telescopes. “Thus, analysis and new economies of scale enabled by prior analysis into optics, industrial electronics, and the SpaceX StarShip might have the same impression on space astronomy and drive the price of a number of giant observatories down into the regime between the NewSpace projections and ground-based observatories,” they write. (See NewSpace at this hyperlink.)

Launching capabilities play a crucial position in prices. Not simply the expense of a rocket launch itself, however by limiting the dimensions of a telescope‘s primary mirror. The JWST’s major mirror was folded to suit into the Ariane 5’s payload fairing. That meant that it wanted a sophisticated, costly, and dangerous mirror that unfolded whereas it traveled to its place. Launch restrictions had been a big monetary burden on the mission.

However SpaceX’s Starship ought to be capable of load a 6.5-meter mirror in a single piece. “The fairing of the SpaceX Starship has the potential for a 6.5 m JWST-class telescope to be instantly launched with a monolithic mirror, eradicating the fee and complexity of segmented mirror designs,” they write. If that may be dependable, then the 6.5 mirror design could possibly be utilized in a number of telescopes. Most of the price of constructing a 6.5-meter mirror is within the major optic materials, and honeycomb borosilicate mirrors are comparatively cheap. So as a substitute of customized designing and constructing every mirror, we might attain a form of financial system of scale.

The authors say there’s a normal 6.5-meter mirror that nearly suits the invoice, the “… field-proven Richard F. Caris Mirror Lab 6.5 m light-weighted borosilicate honeycomb mirror with out modification.” Honeycombs have the identical benefits as different strong counterparts however are lighter and may be considerably bigger. Borosilicate glass is used as a result of it resists thermal enlargement, is moldable at low temperatures, and is comparatively cheap. For comparability, the JWST’s mirror is manufactured from beryllium and coated with a skinny layer of gold.

A borosilicate mirror in a space telescope would require adaptive optics. However that is one other space the place ground-based telescopes have been a proving floor. The know-how of adaptive optics and wavefront management is getting higher and higher and may be tailored to a 6.5-meter space telescope. Newer, quicker CMOS sensors additionally assist get rid of picture distortion as a result of they want much less time to seize pictures, and so they’re additionally getting bigger and cheaper.

In contrast to the floor of the Earth, space is a radiation free-for-all. Electronics want to have the ability to work on this atmosphere, and so does software program. “Traditionally, purpose-built flight computer systems ran meeting language and required expensive and area of interest software program growth abilities,” the authors write. However that is altering. Industrial off-the-shelf (COTS) electronics are actually being carried out in space missions, and so are frequent working techniques. For instance, the Mars Ingenuity Helicopter runs on Linux, and so do some wavefront management techniques on CubeSats.

The JWST sits on the sun-Earth L2 to do its enterprise. It must be in a thermally steady atmosphere for its highly effective IR sensors to be efficient. However it prices extra to get the telescope there, and it requires extra energy to transmit its information. Douglas and his colleagues say there’s another choice, at the very least for optical telescopes, one utilized by TESS.

TESS is in a 13.7-day interval in Excessive Earth Orbit (HEO.) It used lunar gravity help to get there, which helped decrease launch prices. “The TESS HEO orbit offers a big steady sky protection in a thermally steady low radiation atmosphere for comparatively low Delta V, decreasing the propulsion wants for space observatories and growing potential information downlink relative to L2 orbits for a similar transmitter energy.” TESS’s orbit needs to be steady for many years or longer with out the necessity for propulsion.

Some developments in telescope design decrease the prices whereas in a roundabout way involving know-how. Important developments in design processes have streamlined procedures and decreased prices by saving time. “Over the previous a number of many years, advances in growth processes for software program with model management, project management, test-based design, and steady integration and deployment have elevated the event tempo of more and more advanced software program,” the paper states.

Doc administration may not ignite a lot enthusiasm for many of us, but it surely’s an instance of a crucial piece of the telescope design course of that may profit from enchancment and decrease prices. It takes hundreds of individuals with specialised abilities many years to design, construct, and launch a space telescope. Streamlined communication strategies can assist decrease prices. The authors point out examples like machine-readable paperwork, and utilizing the open-source JSON file format and its schemas to cut back errors. Even change monitoring and automatic distribution of paperwork may be improved to assist decrease prices. “These instruments make an iterative, prototype-heavy design course of extra possible since classes realized are captured naturally,” they clarify.

A few of the adjustments they’ve outlined have already been utilized in SmallSats, CubeSats, and in some instances, even bigger initiatives just like the Nancy Grace Roman House Telescope. In reality, SmallSats present an encouraging have a look at how we will decrease prices with out sacrificing science.

The paper dives into extra technical element, though the authors say this can be a preliminary have a look at the problem and that future papers will dig even deeper. However they’ve proven that there is a approach ahead the place we will proceed to advance astronomy and astrophysics with out creating skyrocketing budgets.

“Future work will present particulars of how such an observatory would possibly come about, further danger mitigation methods, detailed instrument designs, and current the environmental necessities essential for a honey-comb borosilicate mirror to outlive launch,” they conclude.