Exploring space — for science!

These days it seems that most of the space news we hear is about commercial or human missions.

Elon Musk’s SpaceX has launched over 2,000 Starlink communications satellites this year alone and recently completed its 14th next-generation Starship launch, the first to achieve Earth orbit. Human missions this year have included two to the International Space Station, one to the Chinese Tiangong Space Station and the Artemis II mission around the Moon. With rockets blasting off every other day and talk of a new NASA Moon base — see my July 2 article in the Gazette — it’s easy to forget that there are many ongoing U.S. and international space science missions that are making important discoveries.

So today, let’s talk about those missions: where they are going, what they have achieved and hope to achieve, and why we should care about them.

Rush hour in the solar system

While Earth-orbiting satellites dominate the hardware in space today — with over 17,000 operational satellites currently whizzing around our planet — there are a surprising number of spacecraft orbiting other worlds, en route to their destinations, exploring planetary surfaces or even leaving our solar system altogether.

There are three spacecraft orbiting the Moon, mapping its surface and sniffing its rarefied atmosphere. Several landers have visited as well in recent years, some successfully and some failing in various ways.

Mars is the busiest location beyond Earth. As of today, there are six spacecraft orbiting the red planet, including two from NASA, two from the European Space Agency (ESA), one from China and two NASA rovers, Curiosity and Perseverance, which are actively exploring and drilling into Mars’ surface to unlock its secrets.

NASA also has a spacecraft orbiting Jupiter — Juno— and there are two more missions, Europa Clipper (NASA) and JUICE (ESA), that are on their way to explore Jupiter’s large moons. ESA has a spacecraft, BepiColombo, on its way to explore Mercury, and there are even six spacecraft currently in orbit around the Sun, five by the United States alone or in collaboration with ESA, and one by India.

In addition, there are six spacecraft — from NASA, ESA, Japan and China — en route to asteroids, and no fewer than eight space telescopes, including the Hubble (HST) and James Webb Space Telescope (JWST), peering into the deepest regions of the cosmos.

And then there are the New Horizons spacecraft, which flew past dwarf planet Pluto in 2015, and the two Voyager spacecraft, launched way back in 1977, all of which are still partly operational and on escape trajectories to eventually leave the solar system. It’s obvious the solar system is a busy place indeed!

So you might ask, what is all of this expensive space hardware doing to expand scientific knowledge and make life better on Earth? There’s no way to cover the accomplishments of all of these missions in this article, but recent findings are addressing some of humanity’s greatest questions: How did our universe and solar system form? How can we protect our fragile planet? And perhaps the most compelling question of all: Are we alone?

By the way, over the past decade, NASA’s entire budget has averaged just about 0.4 percent of total federal spending. Roughly 30 cents of every dollar in that budget has gone toward scientific research, including the exploration of the universe, our solar system and Earth itself. It’s not nothing, but it’s not even close to what is spent on social programs, defense or interest on the national debt.

Hunting our cosmic origins

Science gives us a broad understanding of the universe’s origins. Multiple independent methods put its age at about 13.8 billion years. Recent JWST observations, however, have revealed surprisingly bright and apparently massive galaxies that existed when the universe was only a few percent of its present age.

Some seem to have formed and evolved faster than current models predict. This raises questions about how galaxies formed so early, although it does not necessarily mean the universe is older than 13.8 billion years.

Meanwhile, the “Hubble tension” — a roughly 9 percent disagreement between methods of measuring the universe’s current expansion rate — remains unresolved. Rather than settling the debate, JWST has strengthened some measurements and uncovered new puzzles, suggesting that our understanding of the early universe, galaxy formation or even the physics of dark matter and dark energy may be incomplete.

In the celestial shooting gallery

The solar system is a busy place, and not just because of all the human-made stuff out there. It is also home to more than a million known asteroids and several thousand known comets.

Of particular concern are the more than 2,500 asteroids classified as potentially hazardous: objects roughly 460 feet or larger whose orbits could bring them, over time, dangerously close to Earth. An impact by one of these behemoths could cause many casualties and severe regional damage.

Fortunately, NASA reports no known asteroid poses a significant impact threat over the next century, but the risk is real enough to warrant preparation. NASA has mounted several asteroid missions, including the Double Asteroid Redirection Test (DART) and — winner of the most tortured-acronym contest—OSIRIS-REx (Origins, Spectral Interpretation, Resource Identification, and Security–Regolith Explorer).

On Sept. 26, 2022, DART deliberately slammed into Dimorphos, a small “moonlet” orbiting the larger asteroid Didymos. The impact shortened Dimorphos’ orbit around its companion by about 33 minutes. Follow-up research also showed a tiny change in the pair’s orbit around the Sun.

This was the first full-scale demonstration that a spacecraft could alter an asteroid’s motion — a promising step toward planetary defense, though the effectiveness of such a strategy would depend on the makeup of the asteroid and how much warning we have.

OSIRIS-REx visited Bennu, another potentially hazardous asteroid, and collected a surface sample that returned to Earth on Sept. 24, 2023. Studying Bennu’s composition will help scientists better understand these objects and plan future planetary defense strategies. The samples also revealed amino acids, all five nucleobases used in DNA and RNA, and sugars including ribose and glucose, all ingredients used by life on Earth. Their presence doesn’t mean that life ever existed on Bennu, but the discoveries do suggest that some of life’s chemical building blocks may be widespread throughout the solar system.

Is there anybody out there?

For at least 2,500 years, people have wondered whether life exists beyond Earth. Finding convincing evidence of extraterrestrial life would rank among the greatest discoveries in human history, and several space missions are investigating whether life could have existed — or might still exist — elsewhere.

Mars is a prime target. Recent analysis of rock samples examined by NASA’s Curiosity rover revealed 21 carbon-containing molecules, seven identified on Mars for the first time. These organic compounds suggest that ancient Mars had chemistry compatible with life, although they could have formed through biological or nonbiological processes.

Meanwhile, the Perseverance rover is exploring Jezero Crater, once home to a lake and river delta. In 2024, it discovered a rock with distinctive “leopard spots” and chemical features that could be associated with ancient microbial activity. This intriguing finding is not proof of life, but the rover has collected samples for return to Earth on a later mission for more detailed study.

Beyond Mars, Jupiter’s moon Europa likely harbors a vast saltwater ocean beneath its icy crust. NASA’s Europa Clipper, en route to Jupiter, is expected to arrive in 2030 and investigate whether Europa has the conditions needed to support life.

NASA’s Dragonfly mission, scheduled to launch no earlier than 2028, will send a nuclear-powered drone the size of a small car to Saturn’s moon Titan to study its rich organic chemistry. It will fly from site to site investigating chemical processes that may shed light on how life’s building blocks form.

Meanwhile, among its other tasks, the James Webb Space Telescope is analyzing the atmospheres of exoplanets — worlds orbiting other stars far beyond our solar system. These observations can help identify potentially habitable environments and search for possible chemical signs of life.

We’ve only begun exploring these possibilities. As current missions continue their work and new ones reach their destinations, we can expect more discoveries — and perhaps one day an answer to one of humanity’s oldest questions.

What’s up in the sky this month?

November is a month for early risers — or insomniacs — with all of the planetary highlights happening either before dawn or after midnight. Mars and Jupiter rise before 1 a.m. on Nov. 1, and two hours earlier by the end of the month. The pair remains about five degrees — about three fingers at arm’s length — apart for the duration of the month.

Venus becomes a morning “star” this month, initially difficult to pick out of the glare of the Sun but rising a little earlier each day. It will be visible near the crescent Moon on Nov. 7 — see the Celestial Highlights sidebar. The planet moves higher and easier to see by the middle of the month.

The exception to the morning planet parade is Saturn. The king of rings rides high all month, visible in the evening as soon as it’s dark and setting well after midnight.

I hope that you take the opportunity to get out and experience the night sky this month. It’s a good time to reconnect with the universe and ponder some of life’s biggest questions.

To get help finding planets, stars and other celestial sights, check out skyandtelescope.org/interactive-sky-chart/ or theskylive.com/.

There are also some great free smartphone apps, including Stellarium, SkySafari and SkyView. As always, if you have questions, comments or suggestions for future articles, you can get in touch with me by email at celestialdeep55@gmail.com. You can find my prior Gazette articles, plus night sky photos and more, on my website at celestialdeep.space/.

Manny Leinz is a longtime amateur astronomer and night-sky photographer. He and his wife live part time in Bootjack, where they have an observatory.