Posted by on February 13, 2021

President’s Column

Things are heating up in new space activity. A lot has happened in the last month. Here’s hoping that it is an indication of things to come. I will briefly summarize some of these events.


The space launch system static test that was supposed to run for 8 minutes was shut down early because of an equipment failure. After testing, they believe that the problem has been corrected. A second test is scheduled for sometime this month. Eight minutes is critical as that is the amount of time that the SLS needs to fire prior to booster drop off in an actual launch. 

President Biden has yet to address his plans for the future of the Artemis program. One hopeful note: he requested a moon rock for display in the Oval Office.

Symbols are important and what a president chooses for the Oval Office Decor can be significant. Here’s hoping that this is an indication of his full support for the program. A question about Artemis at a White House Press Conference produced the answer that no decision has yet been made on the program.


The last two tests of the SpaceX Starship have been less than a complete success. Both SN8 and SN9 had successful flights but exploded on landing. This is disappointing, but if we look back the Falcon 9 also had problems in the beginning that were later resolved. 

The good thing is that Elon Musk is driven. He will not stop everything for months and his team works fast. I predict that SN10 will fly sometime this month and hopefully land successfully. 

Blue Origin

Jeff Bezos has resigned as CEO of Amazon. That decision is, he said, based on his desire to spend more time and effort on his other projects (among them Blue Origin). Here’s hoping that this is the harbinger of more activity from that company.

Space Force

At a recent press conference, the Biden Administration announced that they will keep the Space Force as a branch of the US Military.

Virgin Orbit

Virgin Orbit launched 10 satellites into orbit on January 17th of this year. Another space-capable company has entered the field. 

Rocket Lab

Rocket Lab launched a communications satellite on January 20th of this year, and on January 26th they launched another rocket to orbit and demonstrated that their Curie engine was able to deliver more than 1700 km (1056 mi) of change in distance from the Earth (perigee).

These are exciting times. It appears that commercial activity in space is finally starting to take off in a big way. Perhaps habitats like The Outpost are slowly becoming closer to reality…

Barry Greene

Educational Space

The Search for Martians?
by Anyi Wen

Illustration of a spacecraft carrying the Perseverance rover to Mars (Credit: NASA/JPL-Caltech)

With its freezing cold (average temperature of negative 80 degrees Fahrenheit!) and dust storms, Mars is very inhospitable ‒ harsh or difficult to live in ‒ for us Earthlings. But who are we to say that there aren’t organisms who enjoy its extreme conditions? Even on Earth, there are tough organisms such as water bears and other extremophiles who have adaptations that help them survive in environments that would be dangerous for us and other living things: think extreme heat, cold, or acidic environments! 

Although many scientists are sure there aren’t any living things currently on Mars, there is hope that we might find evidence of past life on Mars back when it was a nicer place to live. Satellite photos of Mars and evidence of water have people questioning whether the “Red Planet” may have once been green and wet. One of the tasks of the upcoming NASA mission to Mars is to look for information about Mars’ past climate, or patterns of weather.

Perseverance’s History

Perseverance is the fifth and most advanced (so far) rover sent by NASA to explore Mars. Launched last year in 2020, Perseverance looks “similar to Curiosity – the NASA rover that’s been exploring Mars since 2012,” but the computers, cameras, and other technology it’s carrying are newer and more powerful (Segal). Did you know that Perseverance was named by a student, just like the other Mars rovers that came before it?

Perseverance’s Mission

What will Perseverance do when it gets to Mars? One major job for Perseverance will be looking for places that may have been able to support life in the past, starting with the Jezero Crater. NASA chose this crater as the landing site because scientists think that it used to be full of water. With the help of scientific tools, Perseverance will explore the Jezero Crater and look for signs of any life (past or present) and clues about what the environment used to be like long ago. After this, the rover will be investigating other sites on the planet in a similar way. Perseverance will also be collecting samples of rocks and soil for a future mission to bring back to Earth for study. These will help scientists learn more about the history of Mars and any “Martians” that might have existed on the planet once. 

The rover will also be helping scientists back home on Earth figure out how to make it safe for humans to visit Mars in the future. NASA says that Perseverance will collect information about the planet’s weather patterns and “[test] a technology for extracting oxygen from the Martian atmosphere, which is 96% carbon dioxide.” Knowing about what weather to expect and having a way to make oxygen with what can be found on Mars can help pave the way for people to visit there one day. Would you want to visit Mars? What would you like to do there, and why? Let us know at

Get Involved

NASA will be landing Perseverance on Mars on February 18. You’re invited to “design, build, and land [your] own spacecraft – just like NASA scientists and engineers do” (Segal). Get a taste of what it might be like to work for NASA, connect with experts, and get a chance at having your work featured. You can register here, and if you’re under 18 be sure to ask your grown-up for permission. These resources are great for learning about Mars and the mission whether you join the challenge or not. There are activities on that website for scientists of all ages to enjoy! Check out this short article, these activities by NASA, and these activities from Science Buddies for more ways you can have fun exploring Mars from the comfort of your home.

In addition, the Mars landing will be broadcast on NASA Television and streamed on their website. It will start on February 18 at 2:15 pm (EST), and the landing is scheduled to happen around 3:55 pm. You can sign up to have your name sent to Mars here. Join people around the world in watching history being made!

Sign up to have your name flown in with a future Mars mission! (Credit: NASA)


Adaptation: special traits or behaviors living things have that allow them to survive in their home environment.
Climate: patterns of weather
Environment: everything around you, including living and non-living things.
Inhospitable: harsh or difficult to live in.
Organism: a living thing such as an animal, plant, or even a single cell.

For More Information

Cowen, A. (2021, February 3). Mars Rover Landing: Space Science & Mars STEM Lessons and Activities. Science Buddies.

Hautaluoma, G., Johnson, A., & Agle, D. (2020, March 5). Virginia Middle School Student Earns Honor of Naming NASA’s Next Mars Rover. NASA.

Langley, L. (2013, August 2).  5 Extreme Life-Forms That Live on the Edge. National Geographic.

May, S. (2020, August 10). What is Mars? NASA.

NASA. (n.d.). Connect Students to #CountdownToMars.

NASA. (n.d.). Mars 2020 Mission Overview.

NASA. (n.d.) Mars for Kids.

NASA. (n.d.). Perseverance Rover’s Landing Site: Jezero Crater.

NASA. (n.d.). Send Your Name to Mars.

Segal, M. (2021, January 8). Celebrate the Perseverance Rover Landing With NASA’s Student Challenge. NASA.

Tavernier, L. (2020, June 17). Meet NASA’s Next Mars Rover, Perseverance, Launching This Summer. NASA.

Wall, M. Mars Rover Finds Ancient Streambed Where Water Once Flowed.

What is Gravity Assist?
by Roxanne Lee

Artistic rendition of the Mariner-Jupiter-Saturn 1977 spacecraft. The spacecraft uses a gravity assist to reach Saturn (Credit: NASA/JPL)

What’s the quickest way to get from one point to another?

If you’re thinking about two points on, say, a piece of paper, then “a straight line” would be the correct answer. However, if you’re thinking about space travel, then that may not apply. And, even if a straight line is the quickest way somewhere, that doesn’t mean it’s the easiest.

Space travel is a complicated endeavor. Moving from one point, like Earth, to another within the solar system, like the Sun, requires a lot of planning. This is what scientists must consider when launching satellites to monitor or take pictures of other moons or planets.

Space travel is complicated by several factors. Some of the major ones are the movement of planets, money, and gravity itself.

Nothing is ever really still in space – planets rotate on their axes, and the spinning planets rotate around the Sun, which also spins. This can make aiming a satellite at a planet difficult – if you just aim for where the planet is, it’ll be gone by the time the satellite arrives.

Another complicating factor is money. Rocket fuel is expensive, and to keep mission costs down rocket scientists want to use as little of it as possible. But if you have to get a satellite to faraway targets like Jupiter, or the Sun, what can you do?

Finally, maybe the greatest concern of all – gravity. Any rocket will have to have enough force to escape the Earth’s gravity, but the gravity concerns don’t stop there. Despite many thinking of space as a weightless place, gravity plays just as big a role out there as on Earth. Sending a satellite from Earth to Mars is relatively simple, because Mars is relatively close to us. But launching a satellite towards the Sun or Saturn is more difficult. Because all planets, including Earth, are moving and have their own gravity, aiming a satellite straight at a faraway planet may just end with the satellite going off course.

A gravity probe orbiting Earth. While getting a satellite to orbit Earth is relatively simple, getting a satellite from Earth to faraway planets is more difficult (Credit: NASA/MSFC)

With gravity, money, and the planets itself working against you – how do you send a satellite far away? To understand, we’re going to have to delve a little bit into gravity itself.

Gravity is one of the four fundamental forces of the universe. It is an invisible attractive force that pulls objects with mass towards each other (Mann 2020). Gravity is what pulls us down to the Earth when we jump. The strength of gravity increases as objects get closer to each other. Gravity is also what keeps the Moon spinning around the Earth – objects with more mass have greater gravity than smaller objects, and pull smaller objects towards them. Because the Earth is bigger than the Moon, it changes the Moon’s direction rather than the other way around (to be fair though, the Moon’s gravity does affect Earth, but because Earth is 81 times larger, not to a degree that we would typically notice). To learn more about gravity and what it’s like in space, check out NASA’s article here.

Hang on – If the Moon is pulled towards the Earth, why doesn’t it crash into the Earth? Well, to be completely accurate, the force of gravity doesn’t necessarily pull objects to it, but instead changes the direction of the object and interferes with its velocity (Allain 2017). Velocity is the rate at which an object changes its position, and is calculated using rate, distance, and time (Zimmerman 2019).

As Allain Rhett describes in his article on, force has different effects on the velocity of an object. When the force of gravity pushes in the same direction as the velocity of an object, the object speeds up. When gravity pushes in the opposite direction of an object’s velocity, the object slows down. Finally, when force pushes perpendicular to the velocity of an object, the object turns without losing or gaining speed. As the article notes, when force acts on an object in both a perpendicular direction and in the same direction as the object’s velocity, the object picks up speed and changes direction.

To bring this full circle, the gravitational force the Earth exerts on the Moon is both perpendicular and in the same direction that the Moon travels. The Moon moves sideways and speeds up as it travels further away from Earth. The farther from Earth it goes, the more it slows down, until gravitational force pulls the Moon back around the Earth, and the Moon orbits Earth once again (Allain, 2017).

A diagram of the Moon orbiting the Earth. It illustrates how the Earth’s gravity acts on the Moon pulling it on its path (Credit: Encyclopedia Brittanica)

Giant hassle, right? Well, we can actually use gravity to our advantage, turning a weakness in space travel into a strength.

One way spacecraft can get where they need to go is by a concept called gravity assist. Gravity assist involves sending a spacecraft close enough to a planet so that the planet’s gravity affects the spacecraft’s velocity (Allain 2017).

The same principle that pulls the Moon around the Earth is what makes gravity assist work. When aimed properly, a satellite can get caught in the gravity of a planet, gain a speed and trajectory change, and speed away to a new destination instead of being caught in the planet’s orbit like a moon (Shortt 2013). This way, a spacecraft like a satellite can change its speed and direction without using too much fuel.

On NASA’s website, they explain the concept with several helpful analogies, which you can check out here. In one scenario, they ask you to imagine a train, representing Jupiter, racing down a track. A child beside the track throws a baseball at the front of the train. The train hits the ball, giving it a huge burst of speed and sends it speeding off in a different direction (Barnett).

Many spacecraft used gravity assist to reach their destinations. One such spacecraft was the Cassini spacecraft. The Cassini-Huygens space missions (called Cassini for short) was a collaboration between NASA, the Italian Space Agency, and the European Space Agency, to send a probe to study Saturn from orbit (Cassini Timeline). Cassini was launched on October 15, 1997 from Cape Canaveral (Cassini Timeline). Cassini was not strong enough to get to Saturn using only its fuel, so the team planned several gravity assists to get Cassini to its destination.

The Cassini-Huygens spacecraft in 1996 (Credit:NASA)

On April 25, 1998, Cassini reached Venus, getting within 176 miles of its surface (NASA). A gravity assist increased Cassini’s velocity to 4 miles per second, sending it on a trajectory similar to the one it had started after leaving Earth. After its second trip around the Sun, Cassini swung by Venus again on June 24, 1999. A few months later, on August 17, it flew by Earth. It was now traveling much faster than it was when it first launched (Cassini Timeline). It passed through the asteroid belt, passed within 6.2 million miles of Jupiter, and finally reached Saturn on July 1, 2004. It was the first probe to orbit a planet beyond the asteroid belt.

Diagram of Cassini’s trajectory towards Saturn. Cassini launched from Earth on Oct 15, 1997, and the map shows its path with the arrow. The arrow is first green, to represent the first leg of the journey, then turns orange, then finally blue. (Credit: NASA)

It took Cassini nearly 7 years to finally reach Saturn. The probe stayed in orbit for 13 years, all the while greatly expanding our knowledge of the planet and its moons. Cassini found potential traces of water on some of Saturn’s moons and evidence of prebiotic chemistry on Titan. It also sent back countless stunning pictures of Saturn and its rings before the probe was destroyed, sent to burn up in Saturn’s orbit so it did not potentially damage any microscopic life on Saturn’s moons.

One of the last photos taken by Cassini before it was destroyed. (Credit: NASA)

Gravity assists are an effective way to navigate the solar system while conserving fuel. Even if rocket fuel significantly improves in the future, gravity assist will still allow us to effectively explore every corner of our solar system.

For More Information

Allain, R. (2017, June 3). Why Doesn’t the Moon Crash Into the Earth? Wired.

Barnett, A. A Gravity Assist Primer. NASA.

Jones, Andrew Zimmerman. (2020, August 26). What Is Velocity in Physics? Thoughtco.

Mann, A. (2020, May 13). What is gravity? NASA.

NASA. (2018, September 25). Cassini Timeline. NASA.

Shortt, D. (2013, September 27). Gravity assist. The Planetary Society.

Closing Words

A Booster Tug for Long-Haul Space Missions
by Barry Greene

Rockets are useful for lifting large weights out of a gravity well. They are not good for long trips. A rocket expends energy in the first few minutes of acceleration. The craft coasts the remainder of the distance. An ion drive can provide continuous, but very low, thrust. This means that it takes a long time to accelerate. If you were to graph delta-v (the change in velocity) and time, it would look like a long, shallow, upward slope. Therefore, an ion engine will take a very long time to reach the velocity that a rocket can achieve in a few minutes. It is only after it reaches that point that the ion engine’s advantage becomes evident.

The ion drive can operate continuously. This slow acceleration adds up. Over time, it can reach speeds far greater than any rocket.

If humans want to travel to other planets, transit times must be reduced dramatically. I believe that the simplest and most economical way to do this is with a booster tug.

The booster tug will be robotically operated. It will consist of a rocket engine, fuel tank, and robot brain that locks onto the craft to provide a powerful initial acceleration. It will then detach and return on a small ion engine to refuel for the next boost. Yes, it will take a while to negate its forward velocity in order to return. However, a robot doesn’t care about time.

In the meanwhile, the craft having eliminated months of tedious acceleration precedes on a much shorter trip.

If the destination has the facilities for producing fuel, another tug could match velocities with the arriving ship and decelerate it. Matching velocity at this stage of the trip is much more difficult and would require a greater expenditure of fuel.

The main difficulty with this procedure is the availability of fuel. If fuel has to come from Earth, it becomes far too expensive to be practical. Fortunately, there is another much cheaper alternative.

It turns out that water is relatively common in space. It has been discovered in lunar craters, asteroids, comets, the Martian moons, and of course Mars itself.

Using solar power, water can be broken down to its component atoms, hydrogen and oxygen. These gases can be burned as fuel.

The robotic technology necessary for the tug’s control is no more complex than what is available today. Advances in propulsion systems will make it possible to achieve ever higher velocities. Using a tug to remove the slow start of the time velocity curve will help to make deep penetration into the solar system ever more practical.

Around the Cosmos

Space Activism

Creative Space

Students participate on the Mission to Mars Student Showcase by JPL. View the rest of the creative work from students all around the world.

Drawing by Manuel from Pasto Nariño, Colombia

Show us your creativity of bringing science and art together! Submit your art to

Space Holidays

  • Space Day – February 3, 1995: NASA launched STS-63 which was historic featuring the first woman shuttle pilot, Eileen M. Collins.

Quote of the Month

“Cultures cannot remain static; they evolve or decline. They explore or expire.”

Buzz Aldrin


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