Watching Artemis lofting skyward I relived the Apollo launches, experiencing feelings that no subsequent missions ever engendered. Artemis involves taking humans back into exploration mode with our spacecraft. Getting people out of low-Earth orbit again is a thrill despite the astonishing cost of the SLS launch vehicle. Obviously finding alternatives that would make more frequent flights possible has a major place on the agenda if we are to contemplate a continuous presence on the Moon, not to mention Mars. But for now, what a kick to see that big bird climb.
The distance between actual goals and dreams sometimes shrinks, and we saw recently that Breakthrough Starshot has made serious progress in developing the engineering concepts for an interstellar flyby. Both Artemis and the evolving Starshot design remind me that while most of the population in any era does not venture far from home, there are always a few who do, and those few change the shape of their civilization. Spaceflight obviously demands hardware and missions. Just as obviously, it demands scientists working on ways to push the envelope to attain still more distant goals. And it demands informing the public about where we are.
Be aware that Jim Benford’s recent interview on the matter is now available online. It’s part of a series of presentations offered by Paul Davies, Sara Walker and Maulik Parikh from the Beyond Center for Fundamental Concepts in Science at Arizona State University. This interview powerfully makes the case for funding Phase 2 of the Starshot program and developing early prototypes. The public needs to know about what has been accomplished and what steps lie ahead.
Having seen Jim Benford’s presentation and the questions David Blair had on that presentation, I watched Blari’s presentation on the “impossibility” of starflight.
My sense is that he used rather strawman arguments to support his points, most of which could be addressed or sidestepped with possible engineering. A good example was his claim that the radiation intercepted by the front of a starship (the size of a Breakthrough Starshot?) would destroy the vessel. However, this can be almost entirely circumvented by rotating the craft to cruise edge on, nassively reducing the surface for particles to impinge on teh surface. For larger ships, a shield can be deployed, much as Clarke’s Magellan used a huge seawater shield to be eroded by the particles in The Songs of Distant Earth. I will leave others to watch Blair’s rather lame reply on this.
Blair does use Bracewell’s findings to introduce his case, although I am not clear how relevant this is, and I believe he misrepresented Bracewell’s chart on the numbers and longevity of civilizations and the distance between them. The Kepler data he uses to support Bracewell’s claim has nothing to do with civilization, of course. [Ref The Galactic Club – Intelligent Life in Outer Space (1976), Fig 9, p62 ]
Bracewell has a chapter in his book: “Twelve: Is Interstellar Travel Possible?”
He accepts that a shield may solve the radiation issue Blair raises. His main argument is the famous racket equation, and the needed mass ratios to reach 99% of c. Yet he then finishes the chapter with the Project Orion concept and a slower travel time, which bypasses his main arguments! Methinks Blair might have read to the end of that chapter before being so reliant on the radiation issue. I thought it was a relatively weak talk, so dismissive of what is a very difficult technological and engineering project, even when machines are doing the mission, not humans.
Blair’s talk for the series is “Interstellar Travel is Bunk!”
The intersection of bubbles can form a flat plane…perhaps alternate polarisation can have the beam pass through to clear the path ahead….bubbles forming some protection.
Here is perhaps a way to stop beam firehosing:
https://phys.org/news/2026-04-compact-flat-lens-generate-nondiffracting.html
The usual media articles on “Why are we going back to the Moon – didn’t we already win that race before?” are tedious. We could have made the same argument when Amundsen reached the South Pole before the ill-fated Scott expedition. Yet today there are many national bases in Antarctica, doing research in a myriad of sciences. If we can get past the race meme and understand that there is exploration and science to be done with a lunar base, and possibly commerce too.
As expensive as the SLS is for the first Artemis missions, it is almost a rounding error compared to the costs of our military spending (and the budget increases requested), and a fraction of what has been spent on just a month of war in Iran. There is no social ROI from war; only the arms manufacturers like war to boost their bottom line. Over the longer term, the Artemis missions will generate a better ROI for society than war.
I’m very pleasantly surprised by the public reception the Artemis mission is getting; it seems a great many people find space exploration inspiring and hopeful in these troubled times. All is not yet lost.
Some of the SLS hate is waning.
Lunar Starship is nowhere in sight, and yet another Raptor has exploded:
https://m.youtube.com/shorts/ILsUTgpsN3A
SLS is the Sport Ute rich uncle Ted bought you, when you wanted a coupe.
It might be so he could show off this or that…but it doesn’t matter.
What you do is say “thank you” instead of kvetching because you might wind up with 100% of nothing instead.
Meanwhile, there is good news on the laser propulsion front:
https://phys.org/news/2026-04-parabolic-flight-lasers-propel-graphene.html
https://advanced.onlinelibrary.wiley.com/doi/10.1002/advs.75050
Trust me, Americans need a positive boost these days. They will take it wherever they can get it.
This also explains to reaction and reception to Project Hail Mary. Even fake aliens that look like rock spiders are welcome.
Gossamer structures can have great strength
https://techxplore.com/news/2026-04-bio-impact-resistance-energy-absorption.html
But I understand some junior Trumps made suspiciously timed investments in arms companies.
Though I love the idea of a laser sail or laser system for that matter a particle beam propulsion is not given as much attention. Surprisingly the divergence of a 100 gigawatt lead ion beam with a frontal surface area of 1sq meter and a time dilation factor of 7500 as in the LHC allows very little beam divergence (magnetic field ignored). This beam can then be concentrated to cause fission or fusion in a much larger craft or just interact with a magnetic field. I put the numbers into the AI mode and it looks sound enough.
@Michael
Over what distance is the particle beam accelerating the craft? Are there any issues with interacting with gravity, making tracking difficult? Is it a neutral beam or a charged beam also subject to magnetic fields?
Do you have a pros and cons list?
Gravity would affect the ion beam just the same way as with light as its going close to it in velocity. Its a positively charged beam and will interact with a magnetic field but it is going so fast the deflection would be small, its time dilation is 7500. The beam can be over very large distances but will interact with gases and electrons in the medium and diverge more.
The discovery of Saturn’s lopsided field an the immense power of Jovian superbolts needs looking at.
Upward superbolts can end as Blue Jets here.
There is a MASSIVE new laser development
https://phys.org/news/2026-04-megawatt-optical-vortices-array.html
Info inputted to AI mode
What is the mass of lead needed to have the kinetic energy of 100 giga joules and a time dilation factor of 7500 (this will give a 100gigawatts if continuous)
Answer 0.148 micrograms
What spacing of lead atoms of 0.148 microgram spread within a cylinder of length 300000 km and a frontal area of 1sq meter
Answer 0.00887m
What is the outer surface ions final velocity of singularly ionised lead of 0.148 microgram spread within a cylinder of length 300000 km and a frontal area of 1sq meter and with an atomic spacing of 0.00887m
Answer~278m/s
If we use the dilation factor of 7500 it hardly deviates over the second it takes to go through 300 000km of space.
I know AI can make mistakes but I cant see it this time, the method it uses looks ok.
@Michael
Can you explain this metric?
The value cannot be the velocity perpendicular to the beam, as it would indicate that the beam disperses far more than the area of the target. What is it exactly?
The particular particle accelerator has to be far out in space, well away from any residual atmosphere that would disrupt the beam. What sort of accelerator would be needed – something the size of the LHC to get to near c velocity? Would it be best placed (and built) on the Moon? Any sense of the cost of such an accelerator?
The particles themselves would have the impact and radiation of the ISM particles that Blair indicated was a showstopper for interstellar travel. Would the craft survive the impact of the particles or vaporize from the impact, especially when the velocity differential is at its highest at the start of the acceleration ramp?
Imagine the rod stream of charged particles expanding outwards due ion repulsion but the time dilation is very high, which reduces the expansion by that amount. It would probably be a mix of LHC and a linac but high time dilation is required to slow the dispersion. By increasing the waist of the accelerator to10sq also reduces the dispersion. The power of the beam say 100gigawatt in 1sq would simplify blow a hole in the ISM and it would need building in space.
Its going to be big and expensive but dispersion is not a limiting factor as much as people think. For 7.5 TeV linac it will be thousands of kilometres long but increasing the waist dramatically lowers the dispersion and therefore the time dilation required (lower length). Catching the particle beam will have to be with superconductors and highly charged plates.
The vomit comet is already hard at work:
Parabolic flight test shows lasers can propel graphene aerogels in microgravity.
https://phys.org/news/2026-04-parabolic-flight-lasers-propel-graphene.html
It’s amusing to read this paper from the UAE where they move a very light sail material under weightless conditions propelled by a very small laser power to move 2 inches!
They don’t know the literature on this subject at all. They seem oblivious to the fact that my team did far more than that under one gravity 26 years ago: On April 5, 2000, we achieved first flight of a beam-driven sail, at JPL. Sails of carbon micro-truss, driven by a microwave beam, were accelerated up to 13 gravities. That same year, on December 8, the Leik Myrabo team, using a carbon-dioxide laser, flew molyebdenum-coated carbon sails at 1 gravity above liftoff, giving velocities up to 3 m/sec.
I had noted the results in the paper, but I hadn’t twigged on the source being predominantly the UAE. The Gulf states are doing a lot to wash their poor reputations, from sports franchises to attracting filming of TV shows and movies. The UAE is especially attractive to the wealthy (although the current Gulf War, with attacks on Dubai, may put a dent in that last).
While it is a Wiley imprint, the predominant submissions and readership are from China, which may be relevant. Journal metrics
About Artemis: I followed part of the launch with emotion, obviously thinking about Apollo 11. However, if the theory of the flight is the same, technology has changed a lot. So it’s an exploit first of all to succeed again this type of mission while integrating new things.
Seen from France, the launch made only one comment in the media, but was quickly forgotten. Only a few specialized magazines mention it (the equivalent of “sky & telescope” mag)
To have a global idea: 90% of the population here never looks up at the sky and is not interested in space; we are 8% passionate about it; 2% remain scientists.
What captivated the world in 1969 – and created a true planetary communion for the first time in human history – is now only “consumable” that we look on social networks to quickly move on. Sensationalism isn’t sensational enough, so we’re not looking any further. People do not realize the incredible difficulties – and risks – that they have to overcome to send these rockets, even with the experience gained.
Worse: I’m sad to have heard again: “What’s the point of sending people ‘to’ the moon; aren’t there more ‘urgent’ things to do?” ; all that is money thrown out the windows, etc. I’m not even talking about the comments saying that Apollo 11 was just a huge studio rigging done with S. Kubrik… I read it here in 2026 ! All this is very sad and socially, it reflects a lot of things…
The launch of a rocket – with human crew – has become completely commonplace among the population in France, perhaps because of the “Arianne-Espace” launchers but also because our astronauts are not raised to the rank of “superheroes”. (unlike the staging of Artemis :) I remember Patrick Baudry who still made us dream in the 80s, but today Thomas Pesquet, even if he has a small reputation, or Sophie Adenot, currently bording on the ISS, are almost unknown. Astronautics has lost some of its magic because the power of the media prefers to look for sensational material elsewhere, which does not develop vocations. The spirit of adventure and what it can bring is no longer with us :(
if I were talking about the solar sails propelled by laser here, I would immediately be taken for a madman :)
I wait for the return of the Artemis crew, passing on the sentence from JFK in his speech by Rice in 1962…
The French don’t look up at the Moon? Well, this has punctured one of those traits that I thought the French had. ;-(