It’s one thing to get from Earth to space, but sometimes you want to do the opposite. You want to get into orbit or touch down gently on the surface of a planet and explore it. How do spacecraft stop? And what does that even mean when everything is orbiting?
The microgravity in space causes a number of problems for astronauts, including bone density loss and muscle atrophy. But there’s another problem: weightlessness allows astronauts’ spines to expand, making them taller. The height gain is permanent while they’re in space, and causes back pain.
A new SkinSuit being tested in a study at King’s College in London may bring some relief. The study has not been published yet.
The constant 24 hour microgravity that astronauts live with in space is different from the natural 24 hour cycle that humans go through on Earth. Down here, the spine goes through a natural cycle associated with sleep.
Sleeping in a supine position allows the discs in the spine to expand with fluid. When we wake up in the morning, we’re at our tallest. As we go about our day, gravity compresses the spinal discs and we lose about 1.5 cm (0.6 inches) in height. Then we sleep again, and the spine expands again. But in space, astronauts spines have been known to grow up to 7 cm. (2.75 in.)
Study leader David A. Green explains it: “On Earth your spine is compressed by gravity as you’re on your feet, then you go to bed at night and your spine unloads – it’s a normal cyclic process.”
In microgravity, the spine of an astronaut is never compressed by gravity, and stays unloaded. The resulting expansion causes pain. As Green says, “In space there’s no gravitational loading. Thus the discs in your spine may continue to swell, the natural curves of the spine may be reduced and the supporting ligaments and muscles — no longer required to resist gravity – may become loose and weak.”
The SkinSuit being developed by the Space Medicine Office of ESA’s European Astronaut Centre and the King’s College in London is based on work done by the Massachusetts Institute of Technology (MIT). It’s a spandex-based garment that simulates gravity by squeezing the body from the shoulders to the feet.
The Skinsuits were tested on-board the International Space Station by ESA astronauts Andreas Mogensen and Thomas Pesquet. But they could only be worn for a short period of time. “The first concepts were really uncomfortable, providing some 80% equivalent gravity loading, and so could only be worn for a couple of hours,” said researcher Philip Carvil.
Back on Earth, the researchers worked on the suit to improve it. They used a waterbed half-filled with water rich in magnesium salts. This re-created the microgravity that astronauts face in space. The researchers were inspired by the Dead Sea, where the high salt content allows swimmers to float on the surface.
“During our longer trials we’ve seen similar increases in stature to those experienced in orbit, which suggests it is a valid representation of microgravity in terms of the effects on the spine,” explains researcher Philip Carvil.
Studies using students as test subjects have helped with the development of the SkinSuit. After lying on the microgravity-simulating waterbed both with and without the SkinSuit, subjects were scanned with MRI’s to test the SkinSuit’s effectiveness. The suit has gone through several design revisions to make it more comfortable, wearable, and effective. It’s now up to the Mark VI design.
“The Mark VI Skinsuit is extremely comfortable, to the point where it can be worn unobtrusively for long periods of normal activity or while sleeping,” say Carvil. “The Mk VI provides around 20% loading – slightly more than lunar gravity, which is enough to bring back forces similar to those that the spine is used to having.”
“The results have yet to be published, but it does look like the Mk VI Skinsuit is effective in mitigating spine lengthening,” says Philip. “In addition we’re learning more about the fundamental physiological processes involved, and the importance of reloading the spine for everyone.”
Joe Pappalardo is the author of the new popular science and technology book, Spaceport Earth: The Reinvention of Spaceflight (The Overlook Press; Available Now). In it, Pappalardo “tackles the ever-changing, 21st-century space industry and what privately funded projects like Elon Musk’s SpaceX mean for the future of space travel.” (Foreign Policy)
Spaceport Earth takes readers on a tour of these high-stakes sites as Pappalardo examines how private companies are reshaping the way we use, intend to use, and view space travel, not solely for scientific exploration but for increasingly more general travel. Visiting every working spaceport in the United States and rocket launches around the world, Pappalardo presents a travelogue and modern history of spaceflight — where the industry is now and what’s on the horizon for explorers and consumers alike—in Spaceport Earth.
If you’ve read enough of our articles, you know I’ve got an uneasy alliance with the Sun. Sure, it provides the energy we need for all life on Earth. But, it’s a great big ongoing thermonuclear reaction, and it’s right there! As soon as we get fusion, Sun, in like, 30 years or so, I tell you, we’ll be the ones laughing.
But to be honest, we still have so many questions about the Sun. For starters, we don’t fully understand the solar wind blasting out of the Sun. This constant wind of charged particles is constantly blowing out into space, but sometimes it’s stronger, and sometimes it’s weaker.
What are the factors that contribute to the solar wind? And as you know, these charged particles are not healthy for the human body, or for our precious electronics. In fact, the Sun occasionally releases enormous blasts that can damage our satellites and electrical grids.
How can we predict the intensity so that we can be better prepared for dangerous solar storms? Especially the Carrington-class events that might take down huge portions of our modern society.
Perhaps the biggest mystery with the Sun is the temperature of its corona. The surface of the Sun is hot, like 5,500 degrees Celsius. But if you rise up into the atmosphere of the Sun, into its corona, the temperature jumps beyond a million degrees.
The list of mysteries is long. And to start understanding what’s going on, we’ll need to get much much closer to the Sun.
Good news, NASA has a new mission in the works to do just that.
The mission is called the Parker Solar Probe. Actually, last week, it was called the Solar Probe Plus, but then NASA renamed it, and that reminded me to do a video on it.
It’s pretty normal for NASA to rename their spacecraft, usually after a dead astronomer/space scientist, like Kepler, Chandra, etc. This time, though, they renamed it for a legendary solar astronomer Eugene Parker, who developed much of our modern thinking on the Sun’s solar wind. Parker just turned 90 and this is the first time NASA has named it after someone living.
Anyway, back to the spacecraft.
The mission is due to launch in early August 2018 on a Delta IV Heavy, so we’re still more than a year away at this point. When it does, it’ll carry the spacecraft on a very unusual trajectory through the inner Solar System.
The problem is that the Sun is actually a very difficult place to reach. In fact, it’s the hardest place to get to in the entire Solar System.
Remember that the Earth is traveling around the Sun at a velocity of 30 km/s. That’s almost three times the velocity it takes to get into orbit. That’s a lot of velocity.
In order to be able to get anywhere near the Sun, the probe needs to shed velocity. And in order to do this, it’s going to use gravitational slingshots with Venus. We’ve talked about gravitational slingshots in the past, and how you can use them to speed up a spacecraft, but you can actually do the reverse.
The Parker Solar Probe will fall down into Venus’ gravity well, and give orbital velocity to Venus. This will put it on a new trajectory which takes it closer to the Sun. It’ll do a total of 7 flybys in 7 years, each of which will tweak its trajectory and shed some of that orbital momentum.
You know, trying to explain orbital maneuvering is tough. I highly recommend that you try out Kerbal Space Program. I’ve learned more about orbital mechanics by playing that game for a few months than I have in almost 2 decades of space journalism. Go ahead, try to get to the Sun, I challenge you.
Anyway, with each Venus flyby, the Parker Solar Probe will get closer and closer to the Sun, well within the orbit of Mercury. Far closer than any spacecraft has ever gotten to the Sun. At its closest point, it’ll only be 5.9 million kilometers from the Sun. Just for comparison, the Earth orbits at an average distance of about 150 million kilometers. That’s close.
And over the course of its entire mission, the spacecraft is expected to make a total of 24 complete orbits of the Sun, analyzing that plasma ball from every angle.
The orbit is also highly elliptical, which means that it’s going really really fast at its closest point. Almost 725,000 km/h.
In order to withstand the intense temperatures of being this close to the Sun, NASA has engineered the Parker Solar Probe to shed heat. It’s equipped with an 11.5 cm-thick shield made of carbon-composite. For that short time it spends really close to the Sun, the spacecraft will keep the shield up, blocking that heat from reaching the rest of its instruments.
And it’s going to get hot. We’re talking about more than 1,300 degrees Celsius, which is about 475 times as much energy as a spacecraft receives here on Earth. In the outer Solar System, the problem is that there just isn’t enough energy to power solar panels. But where Parker is going, there’s just too much energy.
Now we’ve talked about the engineering difficulties of getting a spacecraft this close to the Sun, let’s talk about the science.
The biggest question astronomers are looking to solve is, how does the corona get so hot. The surface is 5,500 Celsius. As you get farther away from the Sun, you’d expect the temperature to go down. And it certainly does once you get as far as the orbit of the Earth.
But the Sun’s corona, or its outer atmosphere, extends millions of kilometers into space. You can see it during a solar eclipse as this faint glow around the Sun. Instead of dropping, the temperature rises to more than a million degrees.
What could be causing this? There are a couple of ideas. Plasma waves pushed off the Sun could bunch up and release their heat into the corona. You could also get the crisscrossing of magnetic field lines that create mini-flares within the corona, heating it up.
The second great mystery is the solar wind, the stream of charged protons and electrons coming from the Sun. Instead of a constant blowing wind, it can go faster or slower. And when the speed changes, the contents of the wind change too.
There’s the slow wind, that goes a mere 1.1 million km/h and seems to emanate from the Sun’s equatorial regions. And then the fast wind, which seems to be coming out of coronal holes, cooler parts in the Sun’s corona, and can be going at 2.7 million km/h.
Why does the solar wind speed change? Why does its consistency change?
The Parker Solar Probe is equipped with four major instruments, each of which will gather data from the Sun and its environment.
The FIELDS experiment will measure the electric and magnetic fields and waves around the Sun. We know that much of the Sun’s behavior is driven by the complex interaction between charged plasma in the Sun. In fact, many physicists agree that magnetohydrodynamics is easily one of the most complicated fields you can get into.
Integrated Science Investigation of the Sun, or ISOIS (which I suspect needs a renaming) will measure the charged particles streaming off the Sun, during regular solar activity and during dangerous solar storms. Can we get any warning before these events occur, giving astronauts more time to protect themselves?
Wide-field Imager for Solar PRobe or WISPR is its telescope and camera. It’s going to be taking close up, high resolution images of the Sun and its corona that will blow our collective minds… I hope. I mean, if it’s just a bunch of interesting data and no pretty pictures, it’s going to be hard to make cool videos showcasing the results of the mission. You hear me NASA, we want pictures and videos. And science, sure.
And then the Solar Wind Electrons Alphas and Protons Investigation, or SWEAP, will measure type, velocity, temperature and density of particles around the Sun, to help us understand the environment around it.
One interesting side note, the spacecraft will be carrying a tiny chip on board with photos of Eugene Parker and a copy of his original 1958 paper explaining the Sun’s solar wind.
I know we’re still more than a year away from liftoff, and several years away before the science data starts pouring in. But you’ll be hearing more and more about this mission shortly, and I’m pretty excited about what it’s going to accomplish. So stay tuned, and once the science comes in, I’m sure you’ll hear plenty more about it.
Did you know that it’s been almost 45 years since humans walked on the surface of the Moon? Of course you do. Anyone who loves space exploration obsesses about the last Apollo landings, and counts the passing years of sadness.
Sure, SpaceX, Blue Origins and the new NASA Space Launch Systems rocket offer a tantalizing future in space. But 45 years. Ouch, so much lost time.
What would happen if we could go back in time? What amazing and insane plans did NASA have to continue exploring the Solar System? What alternative future could we have now, 45 years later?
In order to answer this question, I’ve teamed up with my space historian friend, Amy Shira Teitel, who runs the Vintage Space blog and YouTube Channel. We’ve decided to look at two groups of missions that never happened.
In my half of the series, I look at Werner Von Braun’s insanely ambitious plans to send a human mission to Mars. Put it together with Amy’s episode and you can imagine a space exploration future with all the ambition of the Kerbal Space Program.
Keep mind here that we’re not going to constrain ourselves with the pesky laws of physics, and the reality of finances. These ideas were cool, and considered by NASA engineers, but they weren’t necessarily the best ideas, or even feasible.
So, 2 parts, tackle them in any order you like. My part begins right now.
Werner Von Braun, of course, was the architect for NASA’s human spaceflight efforts during the space race. It was under Von Braun’s guidance that NASA developed the various flight hardware for the Mercury, Gemini and Apollo missions including the massive Saturn V rocket, which eventually put a human crew of astronauts on the Moon and safely returned them back to Earth.
Von Braun was originally a German rocket scientist, pivotal to the Nazi “rocket team”, which developed the ballistic V-2 rockets. These unmanned rockets could carry a 1-tonne payload 800 kilometers away. They were developed in 1942, and by 1944 they were being used in war against Allied targets.
By the end of the war, Von Braun coordinated his surrender to the Allies as well as 500 of his engineers, including their equipment and plans for future rockets. In “Operation Paperclip”, the German scientists were captured and transferred to the White Sands Proving Ground in New Mexico, where they would begin working on the US rocket efforts.
Before the work really took off, though, Von Braun had a couple of years of relative downtime, and in 1947 and 1948, he wrote a science fiction novel about the human exploration of Mars.
The novel itself was never published, because it was terrible, but it also contained a detailed appendix containing all the calculations, mission parameters, hardware designs to carry out this mission to Mars.
In 1952, this appendix was published in Germany as “Das Marsproject”, or “The Mars Project”. And an English version was published a few years later. Collier’s Weekly Magazine did an 8-part special on the Mars Project in 1952, captivating the world’s imagination.
Here’s the plan: In the Mars Project, Von Braun envisioned a vast armada of spaceships that would make the journey from Earth to Mars. They would send a total of 10 giant spaceships, each of which would weigh about 4,000 tonnes.
Just for comparison, a fully loaded Saturn V rocket could carry about 140 tonnes of payload into Low Earth Orbit. In other words, they’d need a LOT of rockets. Von Braun estimated that 950 three-stage rockets should be enough to get everything into orbit.
All the ships would be assembled in orbit, and 70 crewmembers would take to their stations for an epic journey. They’d blast their rockets and carry out a Mars Hohmann transfer, which would take them 8 months to make the journey from Earth to Mars.
The flotilla consisted of 7 orbiters, huge spheres that would travel to Mars, go into orbit and then return back to Earth. It also consisted of 3 glider landers, which would enter the Martian atmosphere and stay on Mars.
Once they reached the Red Planet, they would use powerful telescopes to scan the Martian landscape and search for safe and scientifically interesting landing spots. The first landing would happen at one of the planet’s polar caps, which Von Braun figured was the only guaranteed flat surface for a landing.
At this point, it’s important to note that Von Braun assumed that the Martian atmosphere was about as thick as Earth’s. He figured you could use huge winged gliders to aerobrake into the atmosphere and land safely on the surface.
He was wrong. The atmosphere on Mars is actually only 1% as thick as Earth’s, and these gliders would never work. Newer missions, like SpaceX’s Red Dragon and Interplanetary Transport Ship will use rockets to make a powered landing.
I think if Von Braun knew this, he could have modified his plans to still make the whole thing work.
Once the first expedition landed at one of the polar caps, they’d make a 6,400 kilometer journey across the harsh Martian landscape to the first base camp location, and build a landing strip. Then two more gliders would detach from the flotilla and bring the majority of the explorers to the base camp. A skeleton crew would remain in orbit.
Once again, I think it’s important to note that Von Braun didn’t truly understand how awful the surface of Mars really is. The almost non-existent atmosphere and extreme cold would require much more sophisticated gear than he had planned for. But still, you’ve got to admire his ambition.
With the Mars explorer team on the ground, their first task was to turn their glider-landers into rockets again. They would stand them up and get them prepped to blast off from the surface of Mars when their mission was over.
The Martian explorers would set up an inflatable habitat, and then spend the next 400 days surveying the area. Geologists would investigate the landscape, studying the composition of the rocks. Botanists would study the hardy Martian plant life, and seeing what kinds of Earth plants would grow.
Zoologists would study the local animals, and help figure out what was dangerous and what was safe to eat. Archeologists would search the region for evidence of ancient Martian civilizations, and study the vast canal network seen from Earth by astronomers. Perhaps they’d even meet the hardy Martians that built those canals, struggling to survive to this day.
Once again, in the 1940s, we thought Mars would be like the Earth, just more of a desert. There’d be plants and animals, and maybe even people adapted to the hardy environment. With our modern knowledge, this sounds quaint today. The most brutal desert on Earth is a paradise compared to the nicest place on Mars. Von Braun did the best he could with the best science of the time.
Finally, at the end of their 400 days on Mars, the astronauts would blast off from the surface of Mars, meet up with the orbiting crew, and the entire flotilla would make the return journey to Earth using the minimum-fuel Mars-Earth transfer trajectory.
Although Von Braun got a lot of things wrong about his Martian mission plan, such as the thickness of the atmosphere and habitability of Mars, he got a lot of things right.
He anticipated a mission plan that required the least amount of fuel, by assembling pieces in orbit, using the Hohmann transfer trajectory, exploring Mars for 400 days to match up Earth and Mars orbits. He developed the concept of using orbiters, detachable landing craft and ascent vehicles, used by the Apollo Moon missions.
The missions never happened, obviously, but Von Braun’s ideas served as the backbone for all future human Mars mission plans.
I’d like to give a massive thanks to the space historian David S.F. Portree. He wrote an amazing book called Humans to Mars, which details 50 years of NASA plans to send humans to the Red Planet, including a fantastic synopsis of the Mars Project.
I asked David about how Von Braun’s ideas influenced human spaceflight, he said it was his…
“… reliance on a conjunction-class long-stay mission lasting 400 days. That was gutsy – in the 1960s, NASA and contractor planners generally stuck with opposition-class short-stay missions. In recent years we’ve seen more emphasis on the conjunction-class mission mode, sometimes with a relatively short period on Mars but lots of time in orbit, other times with almost the whole mission spent on the surface.”
You might think you’re reading an educational website, where I explain fascinating concepts in space and astronomy, but that’s not really what’s going on here.
What’s actually happening is that you’re tagging along as I learn more and more about new and cool things happening in the Universe. I dig into them like a badger hiding a cow carcass, and we all get to enjoy the cache of knowledge I uncover.
Okay, that analogy got a little weird. Anyway, my point is. Squirrel!
Fast radio bursts are the new cosmic whatzits confusing and baffling astronomers, and now we get to take a front seat and watch them move through all stages of process of discovery.
Stage 1: A strange new anomaly is discovered that doesn’t fit any current model of the cosmos. For example, strange Boyajian’s Star. You know, that star that probably doesn’t have an alien megastructure orbiting around it, but astronomers can’t rule that out just yet?
Stage 2: Astronomers struggle to find other examples of this thing. They pitch ideas for new missions and scientific instruments. No idea is too crazy, until it’s proven to be too crazy. Examples include dark matter, dark energy, and that idea that we’re living in a
Stage 3: Astronomers develop a model for the thing, find evidence that matches their predictions, and vast majority of the astronomical community comes to a consensus on what this thing is. Like quasars and gamma ray bursts. YouTuber’s make their videos. Textbooks are updated. Balance is restored.
Today we’re going to talk about Fast Radio Bursts. They just moved from Stage 1 to Stage 2. Let’s dig in.
Fast radio bursts, or FRBs, or “Furbys” were first detected in 2007 by the astronomer Duncan Lorimer from West Virginia University.
He was looking through an archive of pulsar observations. Pulsars, of course, are newly formed neutron stars, the remnants left over from supernova explosions. They spin rapidly, blasting out twin beams of radiation. Some can spin hundreds of times a second, so precisely you could set your watch to them.
In this data, Lorimer made a “that’s funny” observation, when he noticed one blast of radio waves that squealed for 5 milliseconds and then it was gone. It didn’t match any other observation or prediction of what should be out there, so astronomers set out to find more of them.
Over the last 10 years, astronomers have found about 25 more examples of Fast Radio Bursts. Each one only lasts a few milliseconds, and then fades away forever. A one time event that can appear anywhere in the sky and only last for a couple milliseconds and never repeats is not an astronomer’s favorite target of study.
Actually, one FRB has been found to repeat, maybe.
The question, of course, is “what are they?”. And the answer, right now is, “astronomers have no idea.”
In fact, until very recently, astronomers weren’t ever certain they were coming from space at all. We’re surrounded by radio signals all the time, so a terrestrial source of fast radio bursts seems totally logical.
Then they sifted through 1,000 terabytes of data and found just 3 fast radio bursts. Three.
Since MOST is farsighted and can’t perceive any radio signals closer than 10,000 km away, the signals had to be coming outside planet Earth. They were “extraterrestrial” in origin.
Right now, fast radio bursts are infuriating to astronomers. They don’t seem to match up with any other events we can see. They’re not the afterglow of a supernova, or tied in some way to gamma ray bursts.
In order to really figure out what’s going on, astronomers need new tools, and there’s a perfect instrument coming. Astronomers are building a new telescope called the Canadian Hydrogen Intensity Mapping Experiment (or CHIME), which is under construction near the town of Penticton in my own British Columbia.
It looks like a bunch of snowboard halfpipes, and its job will be to search for hydrogen emission from distant galaxies. It’ll help us understand how the Universe was expanding between 7 and 11 billion years ago, and create a 3-dimensional map of the early cosmos.
In addition to this, it’s going to be able to detect hundreds of fast radio bursts, maybe even a dozen a day, finally giving astronomers vast pools of signals to study.
What are they? Astronomers have no idea. Seriously, if you’ve got a good suggestion, they’d be glad to hear it.
In these kinds of situations, astronomers generally assume they’re caused by exploding stars in some way. Young stars or old stars, or maybe stars colliding. But so far, none of the theoretical models match the observations.
Another idea is black holes, of course. Specifically, supermassive black holes at the hearts of distant galaxies. From time to time, a random star, planet, or blob of gas falls into the black hole. This matter piles upon the black hole’s event horizon, heats up, screams for a moment, and disappears without a trace. Not a full on quasar that shines for thousands of years, but a quick snack.
The next idea comes with the only repeating fast radio burst that’s ever been found. Astronomers looked through the data archive of the Arecibo Observatory in Puerto Rico and found a signal that had repeated at least 10 times in a year, sometimes less than a minute apart.
Since the quick blast of radiation is repeating, this rules out a one-time collision between exotic objects like neutron stars. Instead, there could be a new class of magnetars (which are already a new class of neutron stars), that can release these occasional shrieks of radio.
Or maybe this repeating object is totally different from the single events that have been discovered so far.
Here’s my favorite idea. And honestly, the one that’s the least realistic. What I’m about to say is almost certainly not what’s going on. And yet, it can’t be ruled out, and that’s good enough for my fertile imagination.
Avi Loeb and Manasvi Lingam at Harvard University said the following about FRBs:
“Fast radio bursts are exceedingly bright given their short duration and origin at distances, and we haven’t identified a possible natural source with any confidence. An artificial origin is worth contemplating and checking.”
Artificial origin. So. Aliens. Nice.
Loeb and Lingam calculated how difficult it would be to send a signal that strong, that far across the Universe. They found that you’d need to build a solar array with twice the surface area of Earth to power the radio wave transmitter.
And what would you do with a transmission of radio or microwaves that strong? You’d use it to power a spacecraft, of course. What we’re seeing here on Earth is just the momentary flash as a propulsion beam sweeps past the Solar System like a lighthouse.
But in reality, this huge solar array would be firing out a constant beam of radiation that would propel a massive starship to tremendous speeds. Like the Breakthrough Starshot spacecraft, but for million tonne spaceships.
In other words, we could be witnessing alien transportation systems, pushing spacecraft with beams of energy to other worlds.
And I know that’s probably not what’s happening. It’s not aliens. It’s never aliens. But in my mind, that’s what I’m imagining.
So, kick back and enjoy the ride. Join us as we watch astronomers struggle to understand what fast radio bursts are. As they invalidate theories, and slowly unlock one of the most thrilling mysteries in modern astronomy. And as soon as they figure it out, I’ll let you know all about it.
What do you think? Which explanation for fast radio bursts seems the most logical to you? I’d love to hear your thoughts and wild speculation in the comments.
On March 30, 2017, SpaceX performed a pretty routine rocket launch. The payload was a communications satellite called SES-10, owned by a company in Luxembourg. And if all goes well, the satellite will eventually make its way to a high orbit of 35,000 km (22,000 miles) and deliver broadcasting and television services to Latin America.
For all intents and purposes, this is an absolutely normal, routine, and maybe even boring event in the space industry. Another chemical rocket blasted off another communications satellite to join the thousands of satellites that have come before.
Of course, as you probably know, this wasn’t a routine launch. It was the first step in one of the most important achievements in space flight – launch reusability. This was the second time the 14-story Falcon 9 rocket had lifted off and pushed a payload into orbit. Not Falcon 9s in general, but this specific rocket was reused.
In a previous life, this booster blasted off on April 8, 2016 carrying CRS-8, SpaceX’s 8th resupply mission to the International Space Station. The rocket launched from Florida’s Cape Canaveral, released its payload, re-entered the atmosphere and returned to a floating robotic barge in the Atlantic Ocean called Of Course I Still Love You. That’s a reference to an amazing series of books by Iain M. Banks.
Why is this such an amazing accomplishment? What does the future hold for reusability? And who else is working on this?
Developing a rocket that could be reused has been one of the holy grails of the space industry, and yet, many considered it an engineering accomplishment that could never be achieved. Trust me, people have tried in the past.
Portions of the space shuttle were reused – the orbiter and the solid rocket boosters. And a few decades ago, NASA tried to develop the X-33 as a single stage reusable rocket, but ultimately canceled the program.
To reuse a rocket makes total sense. It’s not like you throw out your car when you return from a road trip. You don’t destroy your transatlantic airliner when you arrive in Europe. You check it out, do a little maintenance, refuel it, fill it with passengers and then fly it again.
According to SpaceX founder Elon Musk, a brand new Falcon 9 first stage costs about $30 million. If you could perform maintenance, and then refill it with fuel, you’d bring down subsequent launches to a few hundred thousand dollars.
SpaceX is still working out what a “flight-tested” launch will cost on a reused Falcon 9 will cost, but it should turn into a significant discount on SpaceX’s already aggressive prices. If other launch providers think they’re getting undercut today, just wait until SpaceX really gets cranking with these reused rockets.
For most kinds of equipment, you want them to have been re-used many times. Cars need to be taken to the test track, airplanes are flown on many flights before passengers ever climb inside. SpaceX will have an opportunity to test out each rocket many times, figuring out where they fail, and then re-engineering those components. This makes for more durable and safer launch hardware, which I suspect is the actual goal here – safety, not cost.
In addition to the first stage, SpaceX also re-used the satellite fairing. This is the covering that makes the payload more aerodynamic while the rocket moves through the lower atmosphere. The fairing is usually ejected and burns up on re-entry, but SpaceX has figured out how to recover that too, saving a few more million.
SpaceX’s goals are even more ambitious. In addition to the first stage booster and launch fairing, SpaceX is looking to reuse the second stage booster. This is a much more complicated challenge, because the second stage is going much faster and needs to lose a lot more velocity. In late 2014, they put their plans on hold for a second stage reuse.
SpaceX’s next big milestone will be to decrease the reuse time. From almost a year to under 24 hours.
Sometime this year, SpaceX is expected to do the first launch of the Falcon Heavy. A launch system that looks like it’s made up of 3 Falcon-9 rockets bolted together. Since that’s basically what it is.
The center booster is a reinforced Falcon-9, with two additional Falcon-9s as strap-on boosters. Once the Falcon Heavy lifts off, the three boosters will detach and will individually land back on Earth, ready for reassembly and reuse. This system will be capable of carrying 54,000 kilograms into low Earth orbit. In addition, SpaceX is hoping to take the technology one more step and have the upper stage return to Earth.
Imagine it. Three boosters and upper stage and payload fairing all returning to Earth and getting reused.
And waiting in the wings, of course, is SpaceX’s huge Interplanetary Transport System, announced by Elon Musk in September of 2016. The super-heavy lift vehicle will be capable of carrying 300,000 kilograms into low Earth orbit.
For comparison, the Apollo era Saturn V could carry 140,000 kg into low Earth orbit, so this thing will be much much bigger. But unlike the Saturn V, it’ll be capable of returning to Earth, and landing on its launch pad, ready for reuse.
SpaceX just crossed a milestone, but they’re not the only player in this field.
Perhaps the biggest competitor to SpaceX comes from another internet entrepreneur: Amazon’s Jeff Bezos, the 2nd richest man in the world after Bill Gates. Bezos founded his own rocket company, Blue Origin in Seattle, which had been working in relative obscurity for the last decade. But in the last few years, they demonstrated their technology for reusable rocket flight, and laid out their plans for competing with SpaceX.
In April 2015, Blue Origin launched their New Shepard rocket on a suborbital trajectory. It went up to an altitude of about 100 km, and then came back down and landed on its launch pad again. It made a second flight in November 2015, a third flight in April 2016, and a fourth flight in June 2016.
That does sound exciting, but keep in mind that reaching 100 km in altitude requires vastly less energy than what the Spacex Falcon 9 requires. Suborbital and orbital are two totally milestones. The New Shepard will be used to carry paying tourists to the edge of space, where they can float around weightlessly in the vomit of the other passengers.
But Blue Origin isn’t done. In September 2016, they announced their plans for the follow-on New Glenn rocket. And this will compete head to head with SpaceX. Scheduled to launch by 2020, like, within 3 years or so, the New Glenn will be an absolute monster, capable of carrying 45,000 kilograms of cargo into low Earth orbit. This will be comparable to SpaceX’s Falcon Heavy or NASA’s Space Launch System.
Like the Falcon 9, the New Glenn will return to its launch pad, ready for a planned reuse of 100 flights.
A decade ago, the established United Launch Alliance – a consortium of Boeing and Lockheed-Martin – was firmly in the camp of disposable launch systems, but even they’re coming around to the competition from SpaceX. In 2014, they began an alliance with Blue Origin to develop the Vulcan rocket.
The Vulcan will be more of a traditional rocket, but some of its engines will detach in mid-flight, re-enter the Earth’s atmosphere, deploy parachutes and be recaptured by helicopters as they’re returning to the Earth. Since the engines are the most expensive part of the rocket, this will provide some cost savings.
There’s another level of reusability that’s still in the realm of science fiction: single stage to orbit. That’s where a rocket blasts off, flies to space, returns to Earth, refuels and does it all over again. There are some companies working on this, but it’ll be the topic for another episode.
Now that SpaceX has successfully launched a first stage booster for the second time, this is going to become the new normal. The rocket companies are going to be fine tuning their designs, focusing on efficiency, reliability, and turnaround time.
These changes will bring down the costs of launching payloads to orbit. That’ll mean it’s possible to launch satellites that were too expensive in the past. New scientific platforms, communications systems, and even human flights become more reasonable and commonplace.
Of course, we still need to take everything with a grain of salt. Most of what I talked about is still under development. That said, SpaceX just reused a rocket. They took a rocket that already launched a satellite, and used it to launch another satellite.
It’s a pretty exciting time, and I can’t wait to see what happens next.
Now you know how I feel about this accomplishment, I’d like to hear your thoughts. Do you think we’re at the edge of a whole new era in space exploration, or is this more of the same? Let me know your thoughts in the comments.
Beginning in the 1950s with the Sputnik, Vostok and Mercury programs, human beings began to “slip the surly bonds of Earth”. And for a time, all of our missions were what is known as Low-Earth Orbit (LEO). Over time, with the Apollo missions and deep space missions involving robotic spacecraft (like the Voyager missions), we began to venture beyond, reaching the Moon and other planets of the Solar System.
But by and large, the vast majority of missions to space over the years – be they crewed or uncrewed – have been to Low-Earth Orbit. It is here that the Earth’s vast array of communications, navigation and military satellites reside. And it is here that the International Space Station (ISS) conducts its operations, which is also where the majority of crewed missions today go. So just what is LEO and why are we so intent on sending things there?
Technically, objects in low-Earth orbit are at an altitude of between 160 to 2,000 km (99 to 1200 mi) above the Earth’s surface. Any object below this altitude will being to suffer from orbital decay and will rapidly descend into the atmosphere, either burning up or crashing on the surface. Objects at this altitude also have an orbital period (i.e. the time it will take them to orbit the Earth once) of between 88 and 127 minutes.
Objects that are in a low-Earth orbit are subject to atmospheric drag since they are still within the upper layers of Earth’s atmosphere – specifically the thermosphere (80 – 500 km; 50 – 310 mi), theremopause (500–1000 km; 310–620 mi), and the exosphere (1000 km; 620 mi, and beyond). The higher the object’s orbit, the lower the 1atmospheric density and drag.
However, beyond 1000 km (620 mi), objects will be subject to Earth’s Van Allen Radiation Belts – a zone of charged particles that extends to a distance of 60,000 km from the Earth’s surface. In these belts, solar wind and cosmic rays have been trapped by Earth’s magnetic field, leading to varying levels of radiation. Hence why missions to LEO aim for attitudes between 160 to 1000 km (99 to 620 mi).
Within the thermosphere, thermopause and exosphere, atmospheric conditions vary. For instance, the lower part of the thermosphere (from 80 to 550 kilometers; 50 to 342 mi) contains the ionosphere, which is so-named because it is here in the atmosphere that particles are ionized by solar radiation. As a result, any spacecraft orbiting within this part of the atmosphere must be able to withstand the levels of UV and hard ion radiation.
Temperatures in this region also increase with height, which is due to the extremely low density of its molecules. So while temperatures in the thermosphere can rise as high as 1500 °C (2700 °F), the spacing of the gas molecules means that it would not feel hot to a human who was in direct contact with the air. It is also at this altitude that the phenomena known as Aurora Borealis and Aurara Australis are known to take place.
The Exosphere, which is outermost layer of the Earth’s atmosphere, extends from the exobase and merges with the emptiness of outer space, where there is no atmosphere. This layer is mainly composed of extremely low densities of hydrogen, helium and several heavier molecules including nitrogen, oxygen and carbon dioxide (which are closer to the exobase).
In order to maintain a Low-Earth Orbit, an object must have a sufficient orbital velocity. For objects at an altitude of 150 km and above, an orbital velocity of 7.8 km (4.84 mi) per second (28,130 km/h; 17,480 mph) must be maintained. This is slightly less than the escape velocity needed to get into orbit, which is 11.3 kilometers (7 miles) per second (40,680 km/h; 25277 mph).
Despite the fact that the pull of gravity in LEO is not significantly less than on the surface of Earth (approximately 90%), people and objects in orbit are in a constant state of freefall, which creates the feeling of weightlessness.
Uses of LEO:
In this history of space exploration, the vast majority of human missions have been to Low Earth Orbit. The International Space Station also orbits in LEO, between an altitude of 320 and 380 km (200 and 240 mi). And LEO is where the majority of artificial satellites are deployed and maintained. The reasons for this are quite simple.
For one, the deployment of rockets and space shuttles to altitudes above 1000 km (610 mi) would require significantly more fuel. And within LEO, communications and navigation satellites, as well as space missions, experience high bandwidth and low communication time lag (aka. latency).
For Earth observation and spy satellites, LEO is still low enough to get a good look at the surface of Earth and resolve large objects and weather patterns on the surface. The altitude also allows for rapid orbital periods (a little over one hour to two hours long), which allows them to be able to view the same region on the surface multiple times in a single day.
And of course, at altitudes between 160 and 1000 km from the Earth’s surface, objects are not subject to the intense radiation of the Van Allen Belts. In short, LEO is the simplest, cheapest and safest location for the deployment of satellites, space stations, and crewed space missions.
Issues with Space Debris:
Because of its popularity as a destinations for satellites and space missions, and with increases in space launches over the past few decades, LEO is also becoming increasingly congested with space debris. This takes the form of discarded rocket stages, non-functioning satellites, and debris created by collisions between large pieces of debris.
The existence of this debris field in LEO has led to growing concern in recent years, since collisions at high-velocities can be catastrophic for space missions. And with every collision, additional debris is created, creating a destructive cycle known as the Kessler Effect – which is named after NASA scientist Donald J. Kessler, who first proposed it in 1978.
In 2013, NASA estimated that there may be as much as 21,000 bits of junk bigger than 10 cm, 500,000 particles between 1 and 10 cm, and more than 100 million smaller than 1 cm. As a result, in recent decades, numerous measures have been taken to monitor, prevent, and mitigate space debris and collisions.
For instance, in 1995, NASA became the first space agency in the world to issue a set of comprehensive guidelines on how to mitigate orbital debris. In 1997, the U.S. Government responded by developing the Orbital Debris Mitigation Standard Practices, based on the NASA guidelines.
NASA has also established the Orbital Debris Program Office, which coordinates with other federal departments to monitor space debris and deal with disruptions caused by collisions. In addition, the US Space Surveillance Network currently monitors some 8,000 orbiting objects that are considered collision hazards, and provides a continuous flow of orbit data to various agencies.
The European Space Agency’s (ESA) Space Debris Office also maintains the Database and Information System Characterizing Objects in Space (DISCOS), which provides information on launch details, orbital histories, physical properties and mission descriptions for all objects currently being tracked by the ESA. This database is internationally recognized and is used by almost 40 agencies, organizations and companies worldwide.
For over 70 years, Low-Earth Orbit has been the playground of human space capability. On occasion, we have ventured beyond the playground and farther out into the Solar System (and even beyond). In the coming decades, a great deal more activity is expected to take place in LEO, which includes the deployment of more satellites, cubesats, continued operations aboard the ISS, and even aerospace tourism.
Needless to say, this increase in activity will require that we do something about all the junk permeating the space lanes. With more space agencies, private aerospace companies, and other participants looking to take advantage of LEO, some serious cleanup will need to take place. And some additional protocols will surely need to be developed to make sure it stays clean.
When it comes to the”Space Race” of the 1960’s, several names come to mind. Names like Chuck Yeager, Yuri Gagarin, Alan Shepard, and Neil Armstrong, but to name a few. These men were all pioneers, braving incredible odds and hazards in order to put a man into orbit, on the Moon, and bring humanity into the Space Age. But about the first women in space?
Were the challenges they faced any less real? Or were they even more difficult considering the fact that space travel, like many professions at the time, were still thought to be a “man’s game”? Well, the first woman to break this glass ceiling was Valentina Tereshkova, a Soviet Cosmonaut who has the distinction of being the first woman ever to go into space as part of the Vostok 6 mission.
Tereshkova was born in the village of Maslennikovo in central Russia (about 280 km north-east of Moscow) after her parents migrated from Belarus. Her father was a tractor driver and her mother worked in a textile plant. Her father became a tank officer and died during the Winter War (1939-1940) when the Soviet Union invaded Finland over a territorial dispute.
Between 1945 to 1953, Tereshkova went to school, but dropped out when she was sixteen, and completed her education through correspondence. Following in her mother’s footsteps, she began working at a textile factory, where she remained until becoming part of the Soviet cosmonaut program.
She became interested in parachuting from a young age and trained in skydiving at the local Aeroclub. In 1959, at the age of 22, she made her first jump. It was her expertise in skydiving that led to her being selected as a cosmonaut candidate a few years later. In 1961, she became the secretary of the local Komsomol (Young Communist League) and later joined the Communist Party of the Soviet Union.
Much like Yuri Gagarin, Tereshkova took part in the Vostok program, which was the Soviet Unions’ first attempts at putting crewed missions into space. After the historic flight of Gagarin in 1961, Sergey Korolyov – the chief Soviet rocket engineer – proposed sending a female cosmonaut into space as well.
At the time, the Soviets believed that sending women into space would achieve a propaganda victory against the U.S., which maintained a policy of only using military and test pilots as astronauts. Though this policy did not specifically discriminate on the basis gender, the lack of women combat and test pilots effectively excluded them from participating.
In April 1962, five women were chosen for the program out of hundreds of potential candidates. These included Tatyana Kuznetsova, Irina Solovyova, Zhanna Yorkina, Valentina Ponomaryova, and Valentina Tereshkova. In order to qualify, the women needed to be parachutists under 30 years of age, under 170 cm (5’7″) in height, and under 70 kg (154 lbs.) in weight.
Along with four colleagues, Tereshkova spent several months in training. This included weightless flights, isolation tests, centrifuge tests, rocket theory, spacecraft engineering, parachute jumps and pilot training in jet aircraft. Their examinations concluded in November 1962, after which Tereshkova and Ponomaryova were considered the leading candidates.
A joint mission profile was developed that would see two women launched into space on separate Vostok missions in March or April of 1963. Tereshkova, then 25, was chosen to be the first woman to go into space, for multiple reasons. First, there was the fact that she conformed to the height and weight specifications to fit inside the relatively cramped Vostok module.
Second, she was a qualified parachutist, which given the nature of the Vostok space craft (the re-entry craft was incapable of landing) was absolutely essential. The third, and perhaps most important reason, was her strong “proletariat” and patriotic background, which was evident from her family’s work and the death of her father (Vladimir Tereshkova) during the Second World War.
Originally, the plan was for Tereshkova to launch first in the Vostok 5 ship while Ponomaryova would follow her into orbit in Vostok 6. However, this flight plan was altered in March 1963, with a male cosmonaut flying Vostok 5 while Tershkova would fly aboard Vostok 6 in June 1963. After watching the successful launch of Vostok 5 on 14 June, Tereshkova (now 26) began final preparations for her own flight.
Tereshkova’s Vostok 6 flight took place on the morning of June 16th, 1963. After performing communications and life support checks, she was sealed inside the capsule and the mission’s two-hour countdown began. The launch took place at 09:29:52 UTC with the rocket lifting off faultlessly from the Baikonur launchpad.
During the flight – which lasted for two days and 22 hours – Tereshkova orbited the Earth forty-eight times. Her flight took place only two days after Vostok 5 was launched, piloted by Valery Bykovsky, and orbited the Earth simultaneously with his craft. In the course of her flight, ground crews collected data on her body’s reaction to spaceflight.
Aside from some nausea (which she later claimed was due to poor food!) she maintained herself for the full three days. Like other cosmonauts on Vostok missions, she kept a flight log and took photographs of the horizon – which were later used to identify aerosol layers within the atmosphere – and manually oriented the spacecraft.
On the first day of her mission, she reported an error in the control program, which made the spaceship ascend from orbit instead of descending. The team on Earth provided Tereshkova with new data to enter into the descent program which corrected the problem. After completing 48 orbits, her craft began descending towards Earth.
Once the craft re-entered the atmosphere, Tereshkova ejected from the capsule and parachuted back to earth. She landed hard after a high wind blew her off course, which was fortunate since she was descending towards a lake at the time. However, the landing caused her to seriously bruise her face, and heavy makeup was needed for the public appearances that followed.
Vostok 6 would be the last of the Vostok misions, despite their being plans for further flights involving women cosmonauts. None of the other four in Tereshkova’s early group got a chance to fly, and, in October of 1969, the pioneering female cosmonaut group was dissolved. It would be 19 years before another woman would fly as part of the Soviet space program – Svetlana Savitskaya, who flew as part of the Soyuz T-7 mission.
After Vostok 6:
After returning home, certain elements within the Soviet Air Force attempted to discredit Tereshkova. There were those who said that she was drunk when she reported to the launch pad and was insubordinate while in orbit. These charges appeared to be related to his sickness she experienced while in space, and the fact that she issued corrections to the ground control team – which was apparently seen as a slight.
She was also accused of drunken and disorderly conduct when confronting a militia Captain in Gorkiy. However, General Nikolai Kamanin – the head of cosmonaut training in the Soviet space program at the time – defended Tereshkova’s character and dismissed her detractors instead. Tereshkova’s reputation remained unblemished and she went on to become a cosmonaut engineer and spent the rest of her life in key political positions.
In November of 1963, Tereshkova married Andrian Nikolayev, another Soviet cosmonaut, at a wedding which took place at the Moscow Wedding Palace. Khrushchev himself presided, with top government and space program leaders in attendance. In June of 1964, she gave birth to their daughter Elena Andrianovna Nikolaeva-Tereshkova, who became the first person in history to have both a mother and father who had traveled into space.
She and Nikolayev divorced in 1982, and Nikolayev died in 2004. She went on to remarry a orthapaedist named Yuliy G. Sharposhnikov, who died in 1999. After her historic flight, Tereshkova enrolled at the Zhukovsky Air Force Academy and graduated with distinction as a cosmonaut engineer. In 1977, she earned her doctorate in engineering.
Her fame as a cosmonaut also led to several key political positions. Between 1966 and 1974, she was a member of the Supreme Soviet of the Soviet Union. She was also a member of the Presidium of the Supreme Soviet from 1974 to 1989, and a Central Committee Member from 1969 to 1991. Her accomplishments also led to her becoming a representative of the Soviet Union abroad.
After the collapse of the Soviet Union, Tereshkova lost her political office, but remained an important public figure. To this day, she is revered as a hero and a major contributor to Russian space program. In 2011, she was elected to the State Duma (the lower house of the Russian legislature) where she continues to serve.
In 2008, Tereshkova was invited to Prime Minister Vladimir Putin’s residence in Novo-Ogaryovo for the celebration of her 70th birthday. In that same year, she became a torchbearer of the 2008 Summer Olympics torch relay in Saint Petersburg, Russia. She has also expressed interest in traveling to Mars, even if it were a one-way trip.
Legacy and Honors:
For her accomplishments, Tereshkova has received many honors and awards. She has been decorated with the Hero of the Soviet Union medal (the USSR’s highest award) as well as the Order of Lenin, the Order of the October Revolution, and many other medals.
Foreign governments have also awarded her with the Karl Marx Order, the Hero of Socialist Labor of Czechoslovakia, the Hero of Labor of Vietnam, the Hero of Mongolia, the UN Gold Medal of Peace, and the Simba International Women’s Movement Award. She has honorary citizenship in multiple cities from Bulgaria, Slovakia, Belarus and Mongolia in the east, to Switzerland, France, and the UK in the west.
Due to her pioneering role in space exploration, a number of astronomical objects and features are named in her honor. For example, the Tereshkova crater on the far side of the Moon was named after her. The minor planet 1671 Chaika (which translates to “Seagull” in Russian) is named in honor of her Vostok 6 mission call sign.
Numerous monuments and statues have been erected in her honor and the Monument to the Conquerors of Space in Moscow features her image. Streets all across the former Soviet Union and Eastern Bloc nations were renamed in her honor, as was the school in Yaroslavl where she studied as a child. The Yaroslavl Planetarium, built in 2011, was created in her honor, and the Museum of V.V. Tereshkova – Cosmos exists near her native village of Maslennikovo.
The Space Age was a time of truly amazing accomplishments. Not only did astronauts like Tereshkova break the surly bonds of Earth, they also demonstrated that space exploration knows no gender restrictions. And though it would be decades before people like Svetlana Savitskaya and Sally Ride would into space, Tereshkova will forever be remembered as the woman who blazed the trail for all female astronauts.
In a previous article, I talked about how you can generate artificial gravity by accelerating at 9.8 meters per second squared. Do that and you pretty much hit the speed of light, then you decelerate at 1G and you’ve completed an epic journey while enjoying comfortable gravity on board at the same time. It’s a total win win.
What I didn’t mention how this acceleration messes up time for you and people who aren’t traveling with you. Here’s the good news. If you accelerate at that pace for years, you can travel across billions of light years within a human lifetime.
Here’s the bad news, while you might experience a few decades of travel, the rest of the Universe will experience billions of years. The Sun you left will have died out billions of years ago when you arrive at your destination.
Welcome to the mind bending implications of constantly accelerating relativistic spaceflight.
With many things in physics, we owe our understanding of relativistic travel to Einstein. Say it with me, “thanks Einstein.”
It works like this. The speed of light is always constant, no matter how fast you’re going. If I’m standing still and shine a flashlight, I see light speed away from me at 300,000 km/s. And if you’re traveling at 99% the speed of light and shine a flashlight, you’ll see light moving away at 300,000 km/s.
But from my perspective, standing still, you look as if you’re moving incredibly slowly. And from your nearly light-speed perspective, I also appear to be moving incredibly slowly – it’s all relative. Whatever it takes to make sure that light is always moving at, well, the speed of light.
This is time dilation, and you’re actually experiencing it all the time, when you drive in cars or fly in an airplane. The amount of time that elapses for you is different for other people depending on your velocity. That amount is so minute that you’ll never notice it, but if you’re traveling at close to the speed of light, the differences add up pretty quickly.
But it gets even more interesting than this. If you could somehow build a rocket capable of accelerating at 9.8 meters/second squared, and just went faster and faster, you’d hit the speed of light in about a year or so, but from your perspective, you could just keep on accelerating. And the longer you accelerate, the further you get, and the more time that the rest of the Universe experiences.
The really strange consequence, though, is that from your perspective, thanks to relativity, flight times are compressed.
I’m using the relativistic star ship calculator at convertalot.com. You should give it a try too.
For starters, let’s fly to the nearest star, 4.3 light-years away. I accelerate halfway at a nice comfortable 1G, then turn around and decelerate at 1G. It only felt like 3.5 years for me, but back on Earth, everyone experienced almost 6 years. At the fastest point, I was going about 95% the speed of light.
Let’s scale this up and travel to the center of the Milky Way, located about 28,000 light-years away. From my perspective, only 20 years have passed by. But back on Earth, 28,000 years have gone by. At the fastest point, I was going 99.9999998 the speed of light.
Let’s go further, how about to the Andromeda Galaxy, located 2.5 million light-years away. The trip only takes me 33 years to accelerate and decelerate, while Earth experienced 2.5 million years. See how this works?
I promised I’d blow your mind, and here it is. If you wanted to travel at a constant 1G acceleration and then deceleration to the very edge of the observable Universe. That’s a distance of 13.8 billion light-years away; you would only experience a total of 45 years. Of course, once you got there, you’d have a very different observable Universe, and billions of years of expansion and dark energy would have pushed the galaxies much further away from you.
Some galaxies will have fallen over the cosmic horizon, where no amount of time would ever let you reach them.
If you wanted to travel 100 trillion light years away, you could make the journey in 62 years. By the time you arrived, the Universe would be vastly different. Most of the stars would have died a long time ago, the Universe would be out of usable hydrogen. You would have have left a living thriving Universe trillions of years in the past. And you could never get back.
Our good friends over at Kurzgesagt covered a very similar topic, discussing the limits of humanity’s exploration of the Universe. It’s wonderful and you should watch it right now.
Of course, creating a spacecraft capable of constant 1G acceleration requires energies we can’t even imagine, and will probably never acquire. And even if you did it, the Universe you enjoy would be a distant memory. So don’t get too excited about fast forwarding yourself trillions of years into the future.