Kendra Pierre-Louis: For Scientific American’s Science Quickly, I’m Kendra Pierre-Louis, in for Rachel Feltman. You’re listening to our weekly science news roundup.
Let’s start off in space.
[CLIP: Sound of a rocket blasting off]
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Last Tuesday NASA announced it will launch a nuclear-powered spacecraft to Mars before the end of 2028. And the agency also said it’s planning to build a base on the moon. SciAm’s senior space and physics editor, Lee Billings, is here to give us the latest updates on space exploration.
Lee Billings: Can I tell you more about NASA’s nuclear-powered Mars mission? Well, as a matter of fact, I can. And it’s really cool—there’s still a lot of stuff that is remaining to be disclosed or to be finalized, but in short it’s something called Space Reactor-1 Freedom, and it’s supposed to launch before the end of 2028.
And what it is, is it’s a nuclear-electric-powered rocket, or spacecraft, that will be transporting something called Skyfall to the Red Planet. And Skyfall is not a James Bond movie; this is three Ingenuity-style Mars copters that are going to be deployed onto Mars, and then they will be carrying cameras and maybe even ground-penetrating radar to scout out signs of—you guessed it—habitability and ancient life, perhaps even, on the Red Planet.
And really, the most exciting thing about this, in my opinion, is this nuclear-electric rocket, which would be the first interplanetary rocket of its kind like this in history, and the transformative capabilities that could bring to space exploration.
And so this was all announced last Tuesday by NASA at this event called “Ignition” in Washington, D.C. And one of the things that also was announced, in addition to this nuclear-electric spacecraft, was more details about NASA’s plans for a permanent moon base. And the reason that these things maybe were both announced at the same time is because they actually are somewhat related. If you want to have a base on the moon, an enduring human presence, and you don’t want all your astronauts to die, then having something like nuclear power on the moon is gonna be pretty significant and pretty essential.
Now, we need to delineate between something like a nuclear reactor that generates electricity on the moon, which is very useful for the very long lunar nights, it gets very cold and very dark, so solar power won’t work then. That’s one thing, but a nuclear rocket is something different. That’s where you use a nuclear reactor to generate electricity that then generates thrust, and you can get much more bang for your buck versus more conventional chemical-based rockets. So it’s different technologies, but they both rely upon nuclear reactions and really highly sensitive fissile material that, you know, can have other nasty uses and applications.
One obvious question here is: What does this really mean for space exploration writ large? Right now we are able to use solar power out to about Jupiter, but past that the sun’s light gets too faint, and it’s really tough to sustain a mission with sufficient power out there.
A lot of people would think the killer app for some kind of nuclear-powered rocket is sending people to Mars. And that’s because if you’re gonna use a chemical rocket for that, you’re talking about launching the equivalent of dozens of International Space stations over time just for fuel. And, you know, if you have a nuclear-powered rocket, on the other hand, it’s a lot easier. You need much less fuel ’cause nuclear power is very energy-dense.
With that said we’ve been here before in prior years, prior decades. There have been multiple pushes by NASA and other parts of the U.S. government to develop these capabilities, and each time they never quite make it to the launchpad. What’s really interesting and I think potentially very important this time is that we’ve never had a NASA administrator and all of NASA kind of united onstage together making the case that this is going to happen so, so clearly. And you really do get the feeling that maybe this time is different because maybe there’s more political support. Now, is there money? Well, presumably if there’s political will, there will be, but that is a big issue. It is a very ambitious target to try to do this before the end of 2028.
So on the heels of all these announcements that happened last week, it’s important to remember that a moon base and nuclear rocketry isn’t all that NASA is doing, and there’s lots of other really cool, exciting stuff in store. And so I could talk your ear off about all that stuff that I’m excited about for hours and hours and hours, but let’s save that for next time.
Pierre-Louis: Thanks, Lee!
Let’s move on from the impacts of nuclear-powered spacecraft and a lunar space base to the impacts of the war in Iran.
The first two weeks of the conflict emitted more than 5.5 million tons of carbon dioxide, according to a late March analysis by the Climate and Community Institute and first reported by the Guardian. That’s slightly more CO2 than was emitted by San Francisco in 2022 and all of Iceland in 2024.
About 15 percent of the emissions comes from carrying out the conflict itself, such as the carbon released while making equipment that has now been destroyed like missile launchers and aircraft and the fuel used in combat. Nearly 40 percent comes from destroyed fuel, as military strikes have targeted fossil fuel infrastructure. In the early days of the conflict, for example, U.S.-Israeli air strikes hit oil depots and a refinery near Tehran, with the resulting pollution triggering black rain.
Gabriel da Silva, an associate professor of chemical engineering at the University of Melbourne, wrote in the Conversation he thinks the black rain, quote, “indicates toxic pollutants such as hydrocarbons, ultrafine particles known as PM2.5, and carcinogenic compounds called polycyclic aromatic hydrocarbons (PAHs) have made their way into the rain.”
In Mid-march after those strikes near Tehran, Israel launched an attack on Iran’s South Pars gas field which is part of the world’s largest gas field. In response, Iran attacked energy facilities across the Gulf, including Qatari liquefied natural gas infrastructure, also known as LNG, eliminating 17 percent of the country’s LNG export capacity, a development first reported by Reuters.
Finally, roughly half of the estimated emissions from the Iran conflict come from the destruction of homes and buildings. The Climate and Community Institute researchers caution that clearing the debris and rebuilding may lead to more emissions than the conflict itself—a stark reminder that it is often easier to destroy a thing than to rebuild it. The researchers found that rebuilding Gaza and Lebanon will likely emit at least 24 times as many emissions as the war destroying those lands because many common building materials are extremely carbon intensive. To make a single ton of concrete, for example, releases just under a ton of carbon dioxide. Considering its ubiquity, that makes concrete responsible for about 8 percent of global greenhouse gas emissions.
The impacts from this conflict are coming at a time when the world needs to drastically slash emissions to stave off the worst effects of climate change. According to the Paris Agreement on climate change, global emissions need to decline 43 percent by 2030 compared with 2019 levels for the Earth to maintain its habitability. A 2025 United Nations report found that the world was falling far short of this goal and was only on track to cut emissions by 17 percent by 2035.
In some optimistic news, last week, pharmaceutical companies Pfizer and Valneva have announced positive results for the phase 3 trial of their Lyme disease vaccine. The bacterial infection is caused by Borrelia bacteria, which is transmitted to humans through tick bites. It gets its name from Lyme, Connecticut, where a cluster of cases was first identified in the late 1970s.
In the short term the infection can cause joint stiffness, muscle aches and pains, and extreme fatigue. If left untreated, however, it can lead to immune system issues, and even arthritis. Estimates suggest that just under half a million people in the U.S. are diagnosed with and treated for Lyme disease each year, according to data from the U.S. Centers for Disease Control and Prevention.
In this trial Pfizer and Valneva took 9,400 volunteers aged five and older from Canada, Europe and the U.S. and randomly assigned them to either receive four doses of the vaccine or a placebo. The researchers found that starting 28 days after the last dose, there were about 73 percent fewer Lyme disease cases among vaccinated people than in the placebo group. The companies went on to say the vaccine was, quote, “well tolerated with no safety concerns identified at time of analysis.”
They said they plan to approach regulators to get the vaccine approved despite missing a key statistical target for a measure called a confidence interval, which helps quantify uncertainty. The central issue was that so few people got Lyme disease during the study period that the trial didn’t meet the threshold needed to declare it successful.
If the companies do win approval, this would not be the first Lyme disease vaccine to reach the market. The first was GlaxoSmithKline’s LYMErix, which had a 76 percent efficacy rate. It was available from 1998 until 2002, when the company pulled it from the market, citing poor sales, after it was plagued by negative media coverage and claims about harmful side effects.
That’s it—that’s our show! Tune in on Wednesday, when we ask an important, pressing question: Why do humans have chins?
Science Quickly is produced by me, Kendra Pierre-Louis, along with Fonda Mwangi, Sushmita Pathak and Jeff DelViscio. This episode was edited by Alex Sugiura. Shayna Posses and Aaron Shattuck fact-check our show. Our theme music was composed by Dominic Smith. Subscribe to Scientific American for more up-to-date and in-depth science news.
For Scientific American, this is Kendra Pierre-Louis. See you next time!