On Jan. 30, 2020, NASA will shut down the Spitzer Space Telescope, ending one of the agency's most scientifically productive space missions before the spacecraft reaches the end of its mechanical life.

Why it matters: Spitzer was designed to make the invisible visible, allowing scientists to investigate galaxies, stars and planet-forming disks. And even today, Spitzer is yielding new insights.

• A study published in April used Spitzer data to reveal that the universe's earliest galaxies were brighter than expected, changing how scientists understand our early universe.
• In 2017, Spitzer confirmed that seven Earth-sized planets orbit the TRAPPIST-1 star located 40 light-years away, marking one of the most important exoplanet discoveries to date.
• When Spitzer's mission ends, scientists will lack similar NASA observational capabilities until NASA's James Webb Space Telescope (JWST) launches in 2021.

The big picture: Spitzer is still functional and could likely continue to operate for another couple of years, but NASA decided its less than $14 million annual operating budget could be better used elsewhere.

"Unfortunately, it's kind of getting to the point where the cost to keep it going is worth more than the science ... that you can get out of it. It's a horrible thing to say about a cost-benefit analysis, but scientifically, it gets that much harder to keep the spacecraft functioning."

Details: Because of the telescope's orbit around the sun, it's actually moving farther and farther from the Earth each year. Eventually, the telescope will be too far away to make meaningful communication possible.

• NASA looked to private companies to take over Spitzer operations, but none could line up funding in time.
• Originally, scientists hoped that JWST and Spitzer would be in space at the same time, gathering data in tandem to calibrate the newer telescope, but lengthy JWST delays made that impossible.

What's next? While Spitzer won't gather new data after the beginning of 2020, scientists will still be able to access the trove of information it did collect to search for new discoveries.

NASA is coming off decades of science beamed back to Earth by big telescopes launched in the 1990s and 2000s.

• As those missions slowly end, the agency and scientists working with them are trying to figure out the future of NASA's astronomy and astrophysics ambitions.

What's next? NASA has a lot riding on the launch of JWST in 2021. The long-delayed infrared-focused telescope is billed as Hubble's successor, and it will mark a turning point for astronomy.

• The telescope promises to explore everything from exoplanet atmospheres to the first light emitted after the dawn of the universe.
• However, the observatory's development has been long mired in delays.
• The telescope is now estimated to cost $9.7 billion after exceeding its $8 billion cap.

On the horizon: The agency's WFIRST mission — which is designed to investigate dark energy and image exoplanets — has been on the budgetary chopping block a number of times, but its funding was reinstated by a House bill reported out of committee on May 22.

• If funding holds, WFIRST will be NASA's next big astrophysics venture in the 2020s.

The bottom line: While NASA focuses its astrophysics resources on large, expensive and highly scrutinized missions like JWST and WFIRST, the agency could be missing out on smaller, less costly telescopes that have huge scientific value.

• NASA's TESS mission, for example, was capped at $200 million, and it is already finding never-before-seen planets around nearby stars.

"I'm worried that we're not diversifying in terms of more medium-sized missions and more small missions and more nanosats. The more and more of that time and energy and budget that gets put into these mega-missions, which just keep getting bigger and bigger, it's a squeeze."

Many skywatchers were delighted to spot a bright line of SpaceX's internet-beaming Starlink satellites pass overhead this weekend, but to astronomers, it was an ominous sign of things to come.

Why it matters: Bright satellites in the night sky can affect astronomy by getting in the way of sensitive, long exposure photos. Usually, researchers can work around these satellites by tracking their orbits and accounting for their predictable movements, but with more satellites come more complications.

• “You take this picture that was meant to be all pretty galaxies and stuff and it ends up being lots of lines across the image where the satellites went by,” astronomer Jonathan McDowell tells Axios.

Driving the news: The 60 Starlink satellites launched by SpaceX on May 23 were unexpectedly bright when they first deployed, McDowell says, rivaling even the brightest stars in the sky and stoking fears about what these satellites might mean for astronomy.

• However, as time passed and the satellites oriented themselves after launch, they stopped looking as bright.
• Still, they will likely shine brightly enough to be visible with the naked eye from dark areas around the world with limited light pollution, McDowell says.

The big picture: While these specific satellites may not be that big of a deal in the long run, the large constellations they portend could be an unexpected contributor to light pollution in the night sky for everyone.

• SpaceX is planning to launch thousands of these satellites over the coming years.
• Amazon’s Project Kuiper is also expected to launch thousands of their broadband satellites, alongside constellations from OneWeb and others.
• For his part, SpaceX founder Elon Musk is aware of the issue, tweeting that he's sent a note to the Starlink team asking about ways to reduce the brightness of the crafts.

Private companies have been launching constellations of Earth-observing satellites for years, but they've been focused on beaming back images taken using visible light. That's starting to change, however, as new firms enter what's currently a niche market: synthetic aperture radar (SAR), Axios science editor Andrew Freedman reports.

Details: SAR allows for data-gathering regardless of weather conditions, making it especially useful for monitoring the planet's disappearing ice sheets that are cloaked in darkness for half the year.

• SAR technology first transmits microwave signals toward the Earth's surface and then receives the signals that are reflected, or backscattered, into space.
• Such technology can sense ground movement and variables that other satellite sensors cannot.
• Applications include monitoring oil spills, mapping forests and monitoring glaciers flowing into the sea.

The players: Three noteworthy companies in this area are Ursa Space Systems, Capella Space and ICEYE.

• Ursa, which has raised nearly $13 million, analyzes and sells SAR data from existing satellite radar providers.
• In the next 3 years, Capella Space, which has raised more than $50 million, is planning to launch its own constellation of 36 small satellites with SAR sensors to obtain hourly coverage of the entire planet, the company tells Axios.
• It has already launched its first SAR satellite, Denali, with a second slated to go up later this year.
• Their constellation will have sub-millimeter resolution, beating larger platforms like Sentinel, founder and CEO Payam Banazadeh tells Axios.
• ICEYE, a Finnish firm, is also launching its own SAR constellation.

Between the lines: While primary business customers may be financial firms and governments, scientists could benefit immensely from new, highly capable SAR constellations.

• This is particularly the case if the data is made freely available for research purposes.
• “We are starting to have good conversations with the science community,” Banazadeh tells Axios.

Stef Lhermitte, a researcher at Delft University of Technology in the Netherlands, uses SAR imagery from ESA's Sentinel satellites to track Antarctic glaciers. He calls such data a "game changer."

• Instead of one image a year giving indications of ice movement, “we now have one image every six days," Lhermitte tells Axios. "You start to see very short-term scale differences.”

A team of scientists was awarded a cache of previously unopened Apollo-era Moon rock samples this year to turn back the clock and see exactly what kinds of materials were abundant on the Moon in its early history.

Why it matters: Researchers have long been interested in figuring out exactly what’s been going on in the interior of our Moon, and this new experiment — which is happening about 50 years after the lunar rock sample was collected — could help create a more complete picture of the history of our natural satellite.

Details: The team will bombard samples of volcanic lunar glass collected during the Apollo 15 mission with photons using the Argonne National Laboratory’s Advanced Photon Source.

• By working backwards and figuring out what minerals are found within the glass, the research team should be able to get a snapshot of what was happening on the Moon millions of years ago.
• “This is all about how planets evolved really,” Darby Dyer, principal investigator for the experiment, tells Axios.

Background: NASA saved some samples of moon rocks from the Apollo program in the hopes that scientists would be able to gain new insights with technology that was yet to be developed.

• Eight other teams will also use untouched moon rock samples for experiments selected by NASA.
• Dyer expects the first results from the experiments to come in March.

The Pentagon launched another space agency. Do we need it? (Sarah Scoles, Wired)

UFOs exist: Get used to it (Daniel Drezner, The Washington Post)

Particle physicist Murray Gell-Mann dies at 89 (Kaveh Waddell, Axios)

SpaceX raised over $1 billion this year (Michael Sheetz, CNBC)

Sirangelo leaves NASA after exploration reorganization scrapped (Jeff Foust, Space News)

A photo taken by Spitzer and released in March shows two galaxies — one large, spiral galaxy and another smaller one — in the act of colliding 272 million light-years from Earth.

• "Different colors correspond to different wavelengths of infrared light. Blue and green are wavelengths both strongly emitted by stars. Red is a wavelength mostly emitted by dust," NASA says in the photo caption.

Our Milky Way is heading for a collision of its own with the Andromeda Galaxy in about 4 billion years. Right now, Andromeda is still located about 2.5 million light-years from Earth, so don't worry about that cosmic crash quite yet.